Highly crimped ultrafine fiber based on solution blowing technology and method for preparing the same

Abstract

The application relates to the technical field of spinning, and provides high-curling superfine fibers based on a solution blowing technology and a preparation method thereof. The high-curling superfine fiber aggregate prepared by the solution blowing technology comprises curling superfine fibers with a diameter less than 1 mu m, and the average bending angle of the curling superfine fibers is greater than or equal to 100 degrees. The solution blowing technology comprises the following steps: after a spinning solution is sprayed out from a spinning hole under the action of an airflow jet, the spinning solution is subjected to drafting and up-and-down whipping forming under the action of a turbulent flow field; the airflow field comprises a laminar flow section and a turbulent flow section; and the straight-line section length of a spinning jet formed by the spinning solution is greater than the length of the laminar flow section. According to the application, the airflow field in the initial stage of fiber forming in the solution blowing technology is designed, the fiber is formed under the action of a turbulent flow field in the initial stage of forming, the average bending angle of the superfine fiber can be obviously increased to more than 100 degrees, the porosity of the obtained superfine fiber aggregate is increased, and the application range of the superfine fiber and the aggregate is widened.

Description

Technical Field

[0001] This invention relates to the field of spinning technology, and in particular to a highly crimped ultrafine fiber based on solution blow spinning technology and its preparation method. Background Technology

[0002] Common methods for preparing fibers include wet spinning, melt-blown spinning, centrifugal spinning, electrospinning, and solution blowing. Different spinning methods produce fibers with varying structures. Wet spinning is difficult to produce fibers with an average diameter below 500 nm; melt-blown spinning produces relatively coarse fibers and has a limited range of applicable fiber types; centrifugal spinning yields fibers with uneven distribution and unstable structures; electrospinning is currently the simplest method for preparing ultrafine fibers, however, its production efficiency is low. Solution blowing can achieve high-throughput preparation of ultrafine fibers, but the resulting ultrafine fibers have a relatively simple structure.

[0003] To improve the application performance of microfibers, structural design is crucial. Cranulated structures can reduce the average pore size of microfiber aggregates, increase their porosity, and enhance their overall performance, offering potential applications in multiple fields. However, even when crimped fibers are obtained using the methods described above, issues such as insufficient crimping or low production efficiency remain. Summary of the Invention

[0004] This invention provides a highly crimped microfiber based on solution blown spinning technology and its preparation method, in order to solve the defect of high-efficiency preparation of microfiber with a highly crimped structure in the prior art.

[0005] In a first aspect, the present invention provides an ultrafine fiber aggregate prepared by solution blown spinning technology, comprising: crimped ultrafine fibers with a diameter of less than 1 μm and wherein the average bending angle of the crimped ultrafine fibers is greater than or equal to 100°.

[0006] Traditional solution blown spinning technology rarely mentions its potential in preparing crimped microfibers. This invention, during the research on mass production of microfibers using solution blown spinning technology, discovered that by changing the state of the spinning jet, a crimped microfiber with significantly superior overall performance compared to existing microfibers can be obtained. This fiber not only possesses a crimped structure, but more importantly, its average bending angle can reach over 100°. This allows for more complex connections between microfibers in the microfiber aggregates obtained by solution blown spinning, enriching the structure of the microfiber aggregates and significantly increasing their application advantages. This provides a novel technical approach for optimizing the porosity, density, thermal conductivity, air permeability, moisture permeability, and hydrophobicity of microfiber aggregates prepared using solution blown spinning technology.

[0007] For microfiber aggregates, the higher the proportion of crimped microfibers with a bending angle of 100° or greater, the higher the structural porosity, the better the material's resilience and stability, and the more prominent its advantages in application. According to the microfiber aggregates provided by the present invention, the crimped microfibers with a bending angle of 90° or greater account for more than 50% of the total number of fibers, preferably more than 60%.

[0008] According to the fiber aggregate provided by the present invention, the porosity of the ultrafine fiber aggregate is greater than or equal to 90%, preferably 90% to 99.999%.

[0009] The crimped microfibers of this invention have a larger bending angle, resulting in higher average porosity and smaller average pore size. Furthermore, the crimped microfibers have a larger specific surface area. Therefore, in the field of adsorption, the crimped microfibers prepared by this invention with a bending angle greater than or equal to 90° have a greater advantage. Simultaneously, the crimped microfibers trap a large amount of still air, effectively reducing various conduction rates, such as heat conduction, sound wave conduction, and electromagnetic conduction. They can also effectively store air and liquids. In addition, a large number of second-phase particles can be doped into the crimped microfibers for the preparation of functional fibers, such as infrared absorbing fibers. In summary, the fiber materials of the above-mentioned dimensions of this invention have application advantages and prospects in the fields of adsorption, conduction, and barrier, such as heat preservation, oil absorption, filtration, hemostasis, anti-inflammation, radiation resistance, sound absorption, and noise reduction.

[0010] According to the fiber aggregate provided by the present invention, the components of the crimped microfiber include one or more of organic polymers, inorganic non-metals, and metals.

[0011] In a second aspect, the present invention also provides a method for preparing the ultrafine fiber aggregates as described above, comprising: using a spinning solution as raw material and obtaining it by solution blowing technology;

[0012] The solution blown spinning technology includes: the spinning solution is ejected from the spinning hole by the action of air jet, and then stretched and whipped up and down by the action of airflow field;

[0013] The airflow field includes a laminar flow section and a turbulent flow section, and the length of the straight section of the spinning jet formed by the spinning solution is greater than the length of the laminar flow section.

[0014] In this invention, the starting position of the airflow field is defined at the outlet of the spinning hole, that is, the starting end of the laminar flow section is at the outlet of the spinning hole.

[0015] In this invention, the starting position of the spinning jet is defined at the outlet of the spinning hole, that is, the starting end of the straight segment of the spinning jet is at the outlet of the spinning hole.

[0016] Experiments have shown that solution blown spinning technology has potential in preparing crimped fibers. This invention fully utilizes the effect of the turbulent section and finds that the location of the turbulent section and the length of the straight section of the spinning jet formed from the spinning orifice outlet are crucial for forming crimped microfibers with an average bending angle of ≥100°. If the laminar flow section is too long, it will result in an excessively long straight section of the spinning jet, leading to problems such as poor microfiber forming effect, poor refining effect, low spinning yield, dripping, low crimping degree of microfibers, and non-fluffy material.

[0017] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2; preferably, the length of the laminar flow section is less than 5 mm.

[0018] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2.5.

[0019] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the length of the spinning hole along the central axis is 0.5 mm to 3 mm; the equivalent diameter of the cross-section of the spinning hole ranges from 0.2 mm to 2.0 mm.

[0020] According to the preparation method of the ultrafine fiber aggregate provided by the present invention, the supply rate of the spinning solution is 0.5 to 10 mL / min, the velocity of the air jet is 2 to 30 m / s, and the receiving distance is 40 cm or more.

[0021] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the airflow pressure is 0.08 MPa or higher.

[0022] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the plurality of spinning holes are located on a needleless spinning mechanism;

[0023] The spinning mechanism includes a hollow cylindrical roller with multiple through-holes formed on the side wall of the roller, which are the spinning holes.

[0024] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, the channels are arranged in multiple rows along the circumference of the roller; the included angle between two adjacent rows of channels ranges from 0.5° to 2°; and the distance between two adjacent channels is less than 1.2 mm. The included angle mentioned above in the present invention refers to the included angle formed along the central axis of the channel.

[0025] According to the preparation method of the ultrafine fiber aggregate provided by the present invention, the porosity of the roller wall is in the range of 40% to 99.9%.

[0026] According to the preparation method of the ultrafine fiber aggregate provided by the present invention, the linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

[0027] According to the method for preparing the ultrafine fiber aggregate provided by the present invention, at least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

[0028] This invention provides a high-crimp ultrafine fiber based on solution blown spinning technology and its preparation method. By designing the airflow field in the initial stage of fiber formation in solution blown spinning technology, the fiber is stretched and whipped up and down in the initial stage of formation by the action of turbulent section, which can significantly increase the average bending angle of ultrafine fiber to more than 100°, thereby increasing the porosity of the obtained ultrafine fiber aggregate and broadening the application range of ultrafine fiber and its aggregate. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a three-dimensional structural schematic diagram of the needleless solution spinning device provided by the present invention;

[0031] Figure 2 This is a front view of the needleless solution spinning apparatus provided by the present invention;

[0032] Figure 3 This is a side view of the needleless solution spinning apparatus provided by the present invention;

[0033] Figure 4 This is a top view of the needleless solution spinning apparatus provided by the present invention;

[0034] Figure 5 This is a schematic diagram of the gas supply mechanism provided by the present invention;

[0035] Figure 6 This is a schematic diagram of the liquid supply mechanism provided by the present invention;

[0036] Figure 7 This is a three-dimensional structural diagram of a roller unit with only one row of holes provided by the present invention;

[0037] Figure 8 This is a front view of the roller unit with multiple rows of channels provided by the present invention;

[0038] Figure 9 This is a schematic diagram of the internal structure of the roller unit with protrusions inside the channel provided by the present invention.

[0039] Figure 10 This is a structural schematic diagram showing the relative positions of the scraping unit and the roller unit provided by the present invention;

[0040] Figure 11 This is a high-speed photographic image of ultrafine fiber forming under an airflow field provided by the present invention;

[0041] Figure 12 This is a wind tunnel experimental diagram of the airflow field provided by the present invention;

[0042] Figure 13 This is a simulation diagram of the airflow field provided by the present invention;

[0043] Figure 14 This is a SEM image of the PVB crimped microfiber in Example 1 provided by the present invention;

[0044] Figure 15 This is a photograph of the PVB crimped ultrafine fiber aggregate in Embodiment 1 provided by the present invention;

[0045] Figure 16 This is a diagram illustrating the room-temperature compressibility of the PVB crimped microfiber aggregate in Embodiment 1 provided by the present invention;

[0046] Figure 17 This is a diagram illustrating the low-temperature compressibility of the PVB crimped ultrafine fiber aggregate in Embodiment 1 provided by the present invention;

[0047] Figure 18 This is a diagram illustrating the thermal insulation effect of the PVB crimped microfiber aggregate in Embodiment 1 of the present invention.

[0048] Figure 19This is a SEM image of the PAN crimped microfiber in Example 2 provided by the present invention;

[0049] Figure 20 This is a photograph of the PAN crimped microfiber aggregate in Embodiment 2 provided by the present invention;

[0050] Figure 21 This is a SEM image of the PVDF-HFP crimped ultrafine fiber in Example 3 of the present invention;

[0051] Figure 22 This is a SEM image of the PMMA crimped ultrafine fibers in Example 4 of the present invention;

[0052] Figure 23 This is a photograph of the PMMA crimped ultrafine fiber aggregate in Embodiment 4 provided by the present invention;

[0053] Figure 24 This is a SEM image of the PCL crimped microfiber in Example 5 of the present invention;

[0054] Figure 25 This is a SEM image of the PLA crimped microfiber in Example 6 of the present invention;

[0055] Figure 26 This is a SEM image of the PU crimped microfiber in Example 7 of the present invention;

[0056] Figure 27 This is a SEM image of the PVP crimped ultrafine fiber in Example 8 of the present invention;

[0057] Figure 28 This is a SEM image of the PAA crimped microfiber in Example 9 of the present invention;

[0058] Figure 29 This is a SEM image of the crimped microfiber of material C in Example 10 of the present invention;

[0059] Figure 30 This is a SEM image of the crimped microfiber of material C in Example 10 of the present invention;

[0060] Figure 31 This is a SEM image of the crimped ultrafine fibers of the Al2O3 precursor in Example 11 of the present invention;

[0061] Figure 32 This is a SEM image of the Al2O3 crimped ultrafine fibers in Example 11 of the present invention;

[0062] Figure 33 These are SEM and EDS images of the SiO2 crimped ultrafine fibers carrying SiO2 aerosol powder in Example 12 of this invention.

[0063] Figure 34 This is a SEM image of the crimped ultrafine fibers of the ZrO2 precursor in Example 16 of the present invention;

[0064] Figure 35 This is a SEM image of the ZrO2 crimped ultrafine fibers in Example 16 of the present invention;

[0065] Figure 36 This is a SEM image of the PI crimped microfiber in Example 17 of the present invention;

[0066] Figure 37 This is a comparison of the crimp of PVB ultrafine fibers prepared by different spinning methods in Comparative Example 2 provided by the present invention; wherein, (a) corresponds to electrospinning, (b) corresponds to air electrospinning, (c) corresponds to air spinning, and (d) corresponds to the embodiment of the present invention.

[0067] Figure 38 This is a schematic diagram of the measurement of bending angle provided by the present invention.

[0068] Figure label:

[0069] 1: Gas supply mechanism; 11: Gas pipeline; 12: Airflow ejection unit; 13: Gas compression unit; 14: Pressure valve; 2: Liquid supply mechanism; 21: Liquid pipeline; 22: Liquid guiding unit; 23: Liquid propulsion unit; 24: Needle; 31: Roller unit; 311: Channel; 312: Protrusion; 32: Scraping unit; 4: Motor; 5: Support structure. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0071] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0072] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0073] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0075] The following is combined with Figures 1 to 38 This invention describes the highly crimped microfiber based on solution blown spinning technology and its preparation method.

[0076] Specifically, in the embodiments of the present invention, an ultrafine fiber aggregate is first provided, which is prepared by solution blowing technology, comprising: crimped ultrafine fibers with a diameter of less than 1 μm and wherein the average bending angle of the crimped ultrafine fibers is greater than or equal to 100°.

[0077] Preferably, the average bending angle of the crimped microfibers in the microfiber aggregate of the present invention can reach 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, or 360°.

[0078] In some embodiments of the present invention, the curled microfibers with a bending angle of 90° or greater account for more than 50% of the total number of fibers in the microfiber aggregate, preferably more than 60%.

[0079] In some embodiments of the present invention, the porosity of the ultrafine fiber aggregate is greater than or equal to 90%, preferably 90% to 99.999%.

[0080] In some embodiments of the present invention, the components of the crimped microfiber include one or more of the following: organic polymers, inorganic non-metals, and metals.

[0081] When the crimped microfiber comprises multiple components, the crimped microfiber is a composite material.

[0082] The organic polymers in this invention include, but are not limited to, one or more combinations of polyvinyl alcohol, polyethylene oxide, polyvinylidene fluoride, polystyrene, polyurethane, polymethyl methacrylate, polylactic acid, polycaprolactone, polyethersulfone, polyvinylpyrrolidone, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polyacrylamide, polyacrylonitrile, polyimide, polyamide, cellulose acetate, methylcellulose, carboxymethyl cellulose, polyaniline, polycarbonate, sodium alginate, chitosan, lignin, and cellulose.

[0083] The inorganic non-metals in this invention include, but are not limited to, one or more combinations of silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, cerium oxide, vanadium oxide, chromium trioxide, manganese dioxide, iron tetroxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, and yttrium oxide.

[0084] The metals used in this invention include, but are not limited to, one or more combinations of silver, aluminum, gold, titanium, zinc, magnesium, and copper.

[0085] In an embodiment of the present invention, a method for preparing the ultrafine fiber aggregates as described above is also provided, comprising: using a spinning solution as raw material and obtaining it by solution blowing technology;

[0086] The solution blown spinning technology includes: the spinning solution is ejected from the spinning hole by the action of air jet, and then stretched and whipped up and down by the action of airflow field;

[0087] The airflow field includes a laminar flow section and a turbulent flow section, and the length of the straight section of the spinning jet formed by the spinning solution is greater than the length of the laminar flow section.

[0088] Taking PVB spinning solution as an example, when PVB ultrafine fibers are prepared using the above method, the high-speed camera image of its formation under the action of an airflow field is shown below. Figure 11 As shown, and also Figures 12-13 As shown, this invention characterizes and simulates the airflow field, and finds that by utilizing the interaction of airflows, the airflow can be transformed from advection to turbulence (non-uniform straight laminar flow develops into homogeneous small vortices), which can form an airflow field containing laminar and turbulent sections. When the length of the straight section of the spinning jet formed by the spinning solution is greater than the length of the laminar section, the spinning jet is solidified into crimped ultrafine fibers by the influence of small vortices in the turbulent section.

[0089] Preferably, the air jet is either advection or turbulence, or a mixture of both.

[0090] In some embodiments of the present invention, the ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2; preferably, the length of the laminar flow section is less than 5 mm.

[0091] In some embodiments of the present invention, the ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2.5.

[0092] In some embodiments of the present invention, the length of the spinning hole along the central axis is 0.5 mm or more; the equivalent diameter of the cross-section of the spinning hole ranges from 0.2 mm to 2.0 mm.

[0093] With the above-mentioned channel length and channel diameter, the "narrow tube effect" of the air jet in the spinning hole can be made more significant while meeting a certain liquid storage capacity, thereby facilitating the formation of turbulence and improving spinning efficiency.

[0094] In some embodiments of the present invention, the supply rate of the spinning solution is 0.5 to 10 mL / min, the velocity of the air jet is 2 to 30 m / s, and the receiving distance is 40 cm or more.

[0095] In some embodiments of the present invention, the airflow pressure is 0.08 MPa or higher, preferably 0.8 to 0.2 MPa. The higher the airflow pressure, the finer the diameter of the microfiber. However, if the pressure is too high, it will easily drip and the fiber-forming property will be poor. If the pressure is too low, the jet cannot be effectively drawn out, and thus microfiber cannot be manufactured.

[0096] Generally, there are no particular limitations on the mass concentration of the spinning solution or the solvent selected in this invention. Since the spinning method of this invention does not rely on devices such as needles, problems such as clogging can be greatly avoided. Therefore, the range of suitable spinning solutions for this invention is greatly broadened, and the solvent and mass concentration of the selected spinning solution can be adjusted according to specific spinning conditions. Generally, a high solution concentration results in more solution residue, which reduces spinning efficiency; a low solution concentration results in poor fiber formation and makes it easier to form droplets.

[0097] In this invention, when preparing crimped microfibers with organic polymer materials as the main component, the solvent used in the spinning solution includes, but is not limited to, one or a combination of two or more of the following: water, methanol, ethanol, n-butanol, n-propanol, isopropanol, hexafluoroisopropanol, tert-butanol, N-methylpyrrolidone, N,N-dimethylformamide, n-heptane, acetonitrile, dichloromethane, chloroform, carbon tetrachloride, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, acetylacetone, butanone, n-hexane, cyclohexane, toluene, xylene, formic acid, and tetrahydrofuran.

[0098] In this invention, the spinning solution used in preparing crimped ultrafine fibers containing inorganic materials includes, but is not limited to, tetraethyl orthosilicate, methyl orthosilicate, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum acetate, zirconium acetate, zirconium propoxide, zirconium butoxide, zirconium hydroxide, cerium nitrate, magnesium acetate, zinc nitrate, silver nitrate, tantalum isopropoxide, niobium acetate, ferric chloride, ferric citrate, germanium isopropoxide, manganese acetate, indium nitrate, zirconium acetylacetonate, yttrium nitrate, yttrium acetate, and copper chloride. One or more of the following: copper acetate, hafnium tetrachloride, hafnium sulfate, hafnium n-butanol, hafnium ethanol, hafnium hydroxide, hafnium oxychloride, hafnium oxynitrate, barium acetate, tin chloride, tantalum pentachloride, cobalt acetate, zinc acetate, nickel acetate, titanium isopropoxide, aluminum isopropoxide, aluminum acetylacetone, tetrabutyl titanate, isobutyl titanate, titanium isopropoxide, zirconium oxychloride, polycarbosilane, chromium nitrate, chromium chloride, tungsten isopropoxide, magnesium nitrate, ferric nitrate, manganese chloride, and cobalt nitrate.

[0099] The feeding rate of the spinning solution can be 0.5 mL / min, 1.5 mL / min, 2.5 mL / min, 3.5 mL / min, 4.5 mL / min, 5.5 mL / min, 6.5 mL / min, 7.5 mL / min, 8.5 mL / min, 9.5 mL / min, or 10 mL / min, etc. This invention has found that if the feeding rate is too slow, the spinning solution remaining in the spinning holes is prone to drying out, making it difficult to form ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality. Conversely, if the feeding rate is too fast, too much spinning solution remains in the spinning holes, easily forming larger droplets during the spinning process, increasing the difficulty of obtaining ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality.

[0100] In some embodiments of the present invention, the plurality of said spinning holes are located on a needleless spinning mechanism.

[0101] The following is combined Figures 1-10 The present invention describes a spinning apparatus comprising the aforementioned needleless spinning mechanism. The spinning apparatus includes: an air supply mechanism 1, a liquid supply mechanism 2, the aforementioned spinning mechanism, a collection mechanism, and a controller, etc.

[0102] The gas supply mechanism 1 is used to eject the gas flow; the liquid supply mechanism 2 is used to supply the spinning solution. Specifically, the gas supply mechanism 1 ejects a high-speed gas flow; the spinning solution ejected by the liquid supply mechanism 2 includes an organic polymer solution or a mixed solution containing organic polymers and inorganic precursors.

[0103] The spinning mechanism includes a roller unit 31, which is a hollow roller rotatably mounted along its axial direction. Multiple radially penetrating channels 311 (i.e., spinning holes) are formed on the side wall of the roller. An air supply mechanism 1 is located inside the roller, and a liquid supply mechanism 2 is located outside the roller. The liquid supply mechanism 2 provides the spinning solution from the outside of the roller. Optionally, the output end of the liquid supply mechanism 2 is positioned above the roller, allowing the spinning solution to flow onto the roller wall under its own gravity. Optionally, the roller wall thickness is 0.5 mm or more. The cross-sectional shape of the channels 311 is one or more combinations of circular, square, star-shaped, slit, and other closed shapes.

[0104] The collection mechanism is located downstream of the air supply mechanism 1 along the air jet direction, that is, on the outside of the drum, and is used to collect the microfiber material.

[0105] The roller unit 31 is equipped with a motor 4 and a controller. The motor 4 is connected to the roller drive and provides the driving force for the roller rotation. The rotational speed of the roller can be adjusted by regulating the power of the motor 4 through the controller, so that its linear speed is maintained between 0.1m / s and 10m / s. The air supply mechanism 1, the liquid supply mechanism 2, and the spinning mechanism are installed as a whole by a support structure 5.

[0106] The working process of the needleless solution spinning device in this embodiment includes:

[0107] The roller unit 31 is activated to keep the roller rotating. The air supply mechanism 1 is activated to continuously spray air from the inside of the roller to the outside, and the liquid supply mechanism 2 is activated to continuously supply spinning solution from the outside of the roller. The spinning solution supplied by the liquid supply mechanism 2 flows from the outer wall of the roller into the channel 311 and remains in the channel 311. When the channel 311 containing the spinning solution rotates to the position of the air supply mechanism 1, the airflow ejected by the air supply mechanism 1 is broken through the channel 311 and blows away the spinning solution remaining in the channel 311, stretching the spinning solution into a spinning jet. The multiple air jets ejected from the multiple channels 311 interact to form turbulence, and the ultrafine fiber material is collected by the collection mechanism.

[0108] The needleless solution spinning apparatus described in the above embodiments of the present invention is particularly suitable for preparing ultrafine fibers, and the apparatus has the following beneficial effects:

[0109] 1. Utilizing the liquid storage advantages of porous channels 311: The three-dimensional structure of channels 311 can uniformly store spinning solution. Porous channels 311 can form a channel array through specific arrangement. The array of channels 311 can uniformly store spinning solution and increase solution storage density.

[0110] 2. Advantages of using the multi-pore channel 311 to form an airflow channel to improve airflow velocity: After the high-speed airflow provided by the air supply mechanism 1 enters the spinning hole from the open area, for incompressible flow, due to the conservation of mass, a "narrowing effect" occurs, and the air mass cannot accumulate in large quantities in the channel 311, which greatly accelerates the airflow velocity in the channel 311. This will help improve the preparation efficiency of ultrafine fibers. Moreover, the turbulent section formed after the airflow exits the spinning hole has a spinning efficiency that is 3 to 20 times higher than that of traditional air spinning and electrostatic spinning.

[0111] 3. Advantages of using the porous channel 311 to disturb the high-speed airflow and accelerate the turbulence transition: The high-speed airflow provided by the air supply mechanism 1 disturbs the high-speed airflow through the porous channel 311, accelerating the transition of the jet after each porous channel 311. The airflow becomes turbulent after passing through the porous channel 311. The interaction between multiple turbulent streams further enhances the average turbulent kinetic energy. The strong turbulence accelerates the curling degree of the ultrafine fiber during the preparation process through vortices with high momentum transfer efficiency. The average bending angle at both ends of the ultrafine fiber per unit length (i.e., 20μm) is greater than or equal to 100°, and even as high as 120° to 360°, which is far higher than that of ultrafine fibers prepared by electrospinning (whose average bending angle is only 10° to 30°).

[0112] 4. Utilizing the advantage of easy cleaning of the multi-channel 311: The spinning solution forms independent units through the channels 311, and the roller can circulate and rotate, which is beneficial for subsequent circulation, cleaning, and spin drying. The spinning time of each channel 311 is much shorter than the cleaning time. The cleaning time can be 20 to 1000 times the spinning time. In other words, the spinning time of each channel is very short, but there is a lot of time for cleaning. The solution that has not been blown out can be thoroughly cleaned. This is an advantage that traditional spinning does not have at all.

[0113] 5. Adjustable rotation speed of roller unit 31: Since the roller can rotate, the range of gas passage and the amount of liquid supply per unit time can be determined by controlling its rotation speed. The linear speed of the roller is 0.1m / s to 10m / s. The higher the rotation speed, the more curled the prepared ultrafine fibers are and the finer the fiber diameter. It can be used to prepare ultrafine fibers of corresponding specifications.

[0114] 6. Circumferential closed structure of roller unit 31: Since the roller is a circumferential closed structure, the channels 311 are arrayed along the closed path (circumferential direction). During the spinning process, the roller rotates continuously, which can realize recycling and ensure the continuity of spinning. The diameter of the roller can be adjusted according to the actual situation.

[0115] The present invention provides a needleless solution spinning device, wherein the porous channel 311 structure arranged on the roller unit 31 can uniformly store the spinning solution and increase the solution storage density; the porous channel 311 forms turbulence, and through turbulent spinning technology, the preparation efficiency of ultrafine fibers can be significantly improved; the porous channel 311 structure is easy to clean; the rotation speed of the roller is adjustable, and ultrafine fibers of corresponding specifications can be prepared; the closed structure and continuous rotation of the roller ensure the continuity of spinning.

[0116] In one embodiment of the present invention, the spinning mechanism further includes a scraping unit 32, which is attached to the outer wall surface of the drum. During the rotation of the drum, the scraping unit 32 scrapes the spinning solution on the outer wall surface of the drum through the relative movement between the scraping unit 32 and the drum, so that the spinning solution is evenly coated on the outer wall surface of the drum, and so that the spinning solution is evenly entered into each channel 311 for continued storage, thereby improving the spinning efficiency. Preferably, the scraping unit 32 is arranged above the drum and close to the liquid supply mechanism 2 (the scraping unit 32 can be arranged behind the liquid supply mechanism 2 along the rotation direction of the drum), so that while the liquid supply mechanism 2 supplies the spinning solution to the outer wall surface of the drum, it scrapes the spinning solution on its outer wall surface evenly. Specifically, the scraping unit 32 can adopt a structure such as a scraper, scraper blade, or scraper plate, preferably made of metal, ceramic, or plastic material, which can not be corroded by the spinning solution. Preferably, multiple scraping units 32 can be arranged and located on the same side or both sides of the liquid supply mechanism 2; for example Figure 10As shown, two scraping units 32 are provided, located on both sides of the liquid supply mechanism 2, to scrape the spinning solution on the outer wall surface of the roller unit 31.

[0117] In one embodiment of the present invention, the gas supply mechanism 1 includes a gas pipeline 11 and an airflow ejection unit 12. The airflow ejection unit 12 is connected to the outlet of the gas pipeline 11, and its ejection direction is along the radial direction of the roller and faces outwards. Specifically, the gas pipeline 11 is used to transport airflow, and a high-speed airflow is ejected through the airflow ejection unit 12 at the outlet of the gas pipeline 11 to break up and blow away the spinning solution remaining in the channel 311. A collection mechanism is provided on the outside of the roller unit 31 to collect the ultrafine fiber material. Preferably, the gas pipeline 11 can be a plastic tube, a metal tube, or a rubber tube; the airflow ejection unit 12 can be a small-diameter hollow tube, a nozzle, an air knife, or a combination thereof.

[0118] In one embodiment of the present invention, the distance between the outlet end of the airflow ejection unit 12 and the inner wall surface of the drum ranges from 0.1 mm to 5 mm. In this embodiment, there is a gap between the outlet end of the airflow ejection unit 12 and the inner wall surface of the drum, allowing the airflow to enter the channel 311 from an open area, which can better form a "narrow tube effect" and is more conducive to the generation of turbulence.

[0119] In one embodiment of the present invention, the gas supply mechanism 1 further includes a gas compression unit 13 and a pressure valve 14. The gas compression unit 13 is connected to the inlet of the gas pipeline 11; the pressure valve 14 is disposed on the gas pipeline 11. In this embodiment, the gas compression unit 13 is utilized. Preferably, the gas is processed by the gas compression unit 13 to form compressed gas, which is then transported through the gas pipeline 11. After the pressure and flow rate of the compressed gas are adjusted by the pressure valve 14, it reaches the airflow ejection unit 12 through the gas pipeline 11 and is ejected from the airflow ejection unit 12 in the form of a high-speed airflow. Preferably, by adjusting the pressure valve 14, the average airflow velocity of the high-speed airflow ejected from the airflow ejection unit 12 is ensured to be in the range of 5 m / s to 100 m / s, and the pressure of the ejected airflow is in the range of 0.05 MPa to 1.0 MPa. Preferably, the gas compression unit 13 can be a high-pressure gas cylinder or an air compressor, etc.

[0120] In one embodiment of the present invention, the liquid supply mechanism 2 includes a liquid pipeline 21 and a liquid guiding unit 22. The liquid guiding unit 22 is connected to the outlet of the liquid pipeline 21 and is located above the roller, serving to guide the spinning solution vertically to the outer wall surface of the roller unit 31. In this embodiment, the liquid pipeline 21 is used to transport the spinning solution, and the liquid guiding unit 22 is used to guide the spinning solution in the liquid pipeline 21 so that the flow direction is perpendicular to the outer wall surface of the roller, thereby allowing the solution to enter the channels 311. Preferably, the liquid pipeline 21 can be a plastic tube, metal tube, or rubber tube, etc.; the liquid guiding unit 22 can be a liquid guiding groove, needle tube, or conduit tube, etc. If a liquid guiding groove is used, its outlet width is preferably the width of one row of channels 311 on the roller; if a needle tube or conduit tube is used, the inner diameter of the needle tube or conduit tube is preferably the width of one row of channels 311 on the roller. Preferably, the distance between the liquid guiding unit 22 and the roller is less than 2 mm, which can stably and uniformly deliver the spinning solution to the outer surface of the roller to the greatest extent.

[0121] In one embodiment of the present invention, the liquid supply mechanism 2 further includes a liquid pusher unit 23, which is connected to the inlet of the liquid pipeline 21 and is used to control the liquid supply rate of the spinning solution. Preferably, the liquid pusher unit 23 is a CNC liquid pusher unit 23, which can be a liquid pump, and the injection rate can be set to ensure that the liquid supply rate is 0.5 mL / min to 10 mL / min. Preferably, a needle tube 24 can be provided at the outlet end of the liquid pusher unit 23, and the port of the needle tube 24 is connected to the liquid pipeline 21.

[0122] In one embodiment of the present invention, the needleless solution spinning apparatus further includes a collecting mechanism disposed on the outside of the roller, for collecting the spinning solution carried away by the air supply mechanism 1 through the channel 311. Specifically, the collecting mechanism can be a box structure or a cylindrical structure. Preferably, the collecting mechanism can be a mesh, a hollow cage, or a roller, and is suitable for obtaining cotton-like or film-like crimped ultrafine fiber aggregates.

[0123] In one embodiment of the present invention, the distance between the collecting mechanism and the center of the roller is 5–100 cm, specifically, it can be 5 cm, 10 cm, 20 cm, 40 cm, 70 cm, or 100 cm. If the distance between the collecting mechanism and the center of the roller is too small, on the one hand, the solvent may not evaporate completely, resulting in a decrease in yield and contamination of the device; on the other hand, because the airflow is ejected and encounters the collecting mechanism, the formed fibers are also ejected due to the backflow of the airflow, affecting the material quality. If the distance between the collecting mechanism and the center of the roller is too large, the dispersion range of the spinning solution jet is too large, making it difficult to collect completely, which also reduces the yield. Therefore, the distance between the collecting mechanism and the center of the roller adopted in this application is beneficial to the formation and collection of crimped ultrafine fibers, while avoiding contamination of the device by the spinning solution.

[0124] In one embodiment of the present invention, at least one protrusion 312 is provided on the inner wall surface of the channel 311, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

[0125] If multiple protrusions are provided, an airflow channel is formed between the protrusions 312, and / or, if one or more protrusions are provided, an airflow channel is formed between the outer surface of the protrusion 312 and the inner wall of the channel 311, to guide the airflow to transition into turbulence. Figure 9 As shown, in this embodiment, protrusions 312 are arranged on the inner wall of the channel 311 to guide the high-speed airflow. These protrusions 312 can be of any shape. On the one hand, the airflow is disturbed after passing through the protrusions 312, facilitating the induction of laminar flow transition to turbulent flow; on the other hand, the spinning solution easily adheres to the protrusions 312 when passing through the channel 311, which is beneficial for solution adhesion. Specifically, the height of the protrusions 312 is smaller than the inner diameter of the channel to form an airflow channel for the airflow to pass through. Furthermore, multiple protrusions 312 can be provided within the channel 311, with multiple protrusions 312 arranged sequentially along the length direction of the channel 311 and / or sequentially arranged along the circumferential direction of the channel 311.

[0126] Considering that a protruding structure can be provided in the channel of the present invention, the channel length can be appropriately increased accordingly, so that the end of the channel still retains a space of more than 0.5 mm along the length direction for liquid storage. Generally, the channel length can be extended to 20 mm.

[0127] In one embodiment of the present invention, the roller is a closed structure in the circumferential direction, and multiple rows (such as two or more) of channels 311 are arranged along the circumference of the roller, with one or more channels 311 arranged in each row along the width direction of the roller. The included angle between two adjacent rows of channels 311 ranges from 0.5° to 2°, the diameter of each channel 311 ranges from 0.2 mm to 2.0 mm, and the distance between two adjacent channels 311 is less than 1.2 mm (measured on one side of the outer wall of the roller). The multiple air jets ejected from the multiple channels interact to form an airflow field including laminar and turbulent sections. When the spinning jet formed by the spinning solution enters the turbulent section, the spinning jet is stretched and whipped by the turbulent section, forming a crimped structure to obtain crimped ultrafine fibers.

[0128] Turbulence is formed through the interaction between multiple air jets. Specifically, in this embodiment, there is a certain angle between the front and rear rows of channels 311 (referring to the angle between the central axes of the front and rear rows of channels 311), which ensures that the spinning solution ejected from each channel 311 does not interfere with each other significantly; using channels 311 with a diameter of 0.2mm to 2.0mm, each channel 311 can be drawn out by at least one spinning jet under the action of airflow. For example, the gap between channels 311 with a diameter of 1 mm is 1.2 mm, and the gap between channels 311 with a diameter of 0.5 mm is 0.6 mm. Therefore, 694,166 channels 311 with a diameter of 1 mm and 2,776,666 channels 311 with a diameter of 0.5 mm can be densely packed in 1 square meter. Taking the channel 311 with a diameter of 1 mm as an example, each spinning hole can be drawn out by airflow, which will make the spinning jet density in 1 square meter reach up to 6,941,660 spinning jets, which is far higher than conventional spinning technology.

[0129] In one embodiment of the present invention, the porosity of the roller unit 31 ranges from 40% to 99.9%. In this embodiment, multiple channels 311 are provided, and multiple rows of channels 311 can be provided, with each row of channels 311 having multiple independent channels 311, thereby forming an array of channels 311, so that the porosity of the roller unit 31 is between 40% and 99.9%. Through the array of channels 311 provided on the roller unit 31, they can be arranged along the circumferential closed structure of the roller unit 31, thereby ensuring the continuity of spinning.

[0130] Furthermore, the volumetric velocity of the air jet near the air jet ejection unit 12 can be 2–30 m / s. Taking an air jet volumetric velocity of approximately 20 m / s near the air jet ejection unit 12 as an example, in terms of turbulence, when there is only a single (one row, one column, 1*1) channel 311, the radial turbulent kinetic energy is only 0.39 m³ / s according to fluid dynamics (CFD) simulation. 2 s -2 When the number of channels 311 increases from one to four (1*4), the radial turbulent kinetic energy increases to 0.91m. 2 s -2 The arrangement was increased to two rows and four columns (2*4), and the radial turbulent kinetic energy was increased to 1.76m. 2 s -2 The radial turbulent kinetic energy was increased to 3.23m when the array was expanded to four rows and four columns (4*4). 2 s -2 It is evident that setting multiple rows and columns of channels 311 is beneficial for increasing radial turbulent kinetic energy. When the radial turbulent kinetic energy is increased to 0.39m... 2 s -2At the above levels, turbulence can be rapidly induced. CFD simulations show that the length of the laminar flow section decreases with increasing number of spinning holes, decreasing sequentially from 4.14 mm to 3.02 mm, 2.27 mm, and 1.71 mm. Experimental tests show that as the laminar flow section decreases, the straight-line length of the spinning jet decreases sequentially from 8.15 mm to 6.92 mm, 5.42 mm, and 5.02 mm. Because the straight-line length of the spinning jet is always greater than the laminar flow section length, it ensures that the spinning jet receives the stretching and whipping action of the turbulent section in the airflow field, thus causing coiling.

[0131] To better utilize the effects of stable and high-intensity turbulence to achieve the preparation of crimped ultrafine fibers, the following relationship is preferred between the airflow field and the spinning jet:

[0132] 1. The ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2, more preferably greater than or equal to 2.5;

[0133] 2. The CFD simulation results show that the length of the laminar flow section of the gas is less than 5 mm;

[0134] 3. The length of the straight section of the spinning jet is less than 9 mm.

[0135] Preferably, the radial turbulent kinetic energy obtained from the CFD simulation is greater than 1.76 m. 2 s -2 ;

[0136] The above relationships can be optimized by adjusting parameters such as the volumetric velocity of the air jet near the airflow ejection unit 12 when the diameter of the channel 311 is 1 mm. Therefore, taking a channel 311 with a diameter of 1 mm as an example, considering processing accuracy, the spacing between channels 311 should be as low as possible (less than 1.2 mm), the number of closely packed channels 311 per square meter should be as high as possible (more than 690,000), and the included angle between each row of channels 311 should be as close to 1.37° as possible. The aperture size should not be too large or too small. Too large an aperture will reduce the spinning hole density and increase the diameter of the microfiber, while too small an aperture will increase airflow resistance. An aperture size of 0.5–1 mm is preferred. The cross-sectional shape of the channel 311 has little impact on the airflow state; considering ease of processing, a round hole is preferred.

[0137] It should be understood that all of the above equipment is made of materials that will not be corroded by the spinning solution.

[0138] The following describes the operation method of the needleless solution spinning apparatus of the present invention. The operation method of the needleless solution spinning apparatus includes the following steps:

[0139] S1. Control the rotation of the drum unit 31, and sequentially start the air supply mechanism 1 and the liquid supply mechanism 2;

[0140] S2. The spinning solution supplied by the liquid supply mechanism 2 flows to the outer wall surface of the roller unit 31 and then continues to exist in the channel 311 on the roller unit 31.

[0141] S3. When the channel 311 containing the spinning solution rotates to the position of the air supply mechanism 1, the airflow ejected by the air supply mechanism 1 breaks through the channel 311 and blows away the spinning solution remaining on the channel 311, stretching the spinning solution into a jet. The multiple airflow jets ejected from the multiple channels 311 interact with each other to form turbulence.

[0142] Specifically, the steps are as follows:

[0143] S100: Turn on the gas compression unit 13 and adjust the gas pressure valve 14 so that the airflow ejection unit 12 ejects high-speed airflow;

[0144] S200, Turn on motor 4 of roller unit 31 so that the roller keeps rotating;

[0145] S300, turn on the CNC liquid push unit 23 so that the spinning solution flows out of the liquid guide tank to the outer wall of the drum and enters the corresponding channel 311;

[0146] S400, under the push of the CNC hydraulic push unit 23, the liquid guide tank transports the spinning solution to the outer wall of the drum and enters the corresponding channel 311. The drum unit 31 keeps rotating. The high-speed airflow ejected by the airflow ejection unit 12 breaks up and blows the spinning solution stored in the channel 311 through the channel 311 on the drum. Finally, the spinning solution is drawn into a jet. The ultrafine fiber material is collected by the collection mechanism. The scraping unit 32 scrapes the outer wall of the drum to make the spinning solution evenly coated on the drum surface.

[0147] The present invention provides a working method for a needleless solution spinning device, which supplies a solution to a supply mechanism 2 and continues to exist in the channels 311 on the roller. The solution is broken and blown away by an air supply mechanism 1, and the spinning solution is drawn into a jet. The multiple jets ejected from multiple channels 311 interact with each other to form turbulence, which significantly improves the preparation efficiency of ultrafine fibers.

[0148] In one embodiment of the present invention, controlling the rotation of the roller unit 31 specifically includes: the roller unit 31 is equipped with a controller, which can control the rotational speed of the roller, and control the linear velocity of the roller to be 0.1 m / s to 10 m / s. The higher the rotational speed of the roller, the more curled the prepared ultrafine fibers are, and the finer the fiber diameter is. Taking the diameter of the roller as 100 mm, its angular velocity is 50 rad / min to 1000 rad / min, specifically, it can be 50 rad / min, 100 rad / min, 200 rad / min, 350 rad / min, 500 rad / min, 750 rad / min, or 1000 rad / min, etc. If the drum rotation speed is too slow, the number of holes through which the high-speed airflow passes per unit time is limited, resulting in limited turbulence intensity and affecting the diameter and average bending angle of the prepared fibers. If the drum unit 31 rotates too fast, the spinning solution is difficult to maintain in the channels 311 on the drum, and less spinning solution is blown and drawn when the high-speed airflow passes through the channels 311. The spinning solution is easily broken by the high-speed airflow, making it difficult to obtain ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality. Therefore, the drum rotation speed of this application is beneficial for obtaining ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality.

[0149] In one embodiment of the present invention, activating the air supply mechanism 1 specifically includes: controlling the average airflow velocity of the airflow ejected by the air supply mechanism 1 to be 5 m / s to 100 m / s, and controlling the pressure of the airflow ejected by the air supply mechanism 1 to be 0.05 MPa to 1.0 MPa. The average airflow velocity of the high-speed airflow ejected by the air supply mechanism 1 is preferably 6 m / s to 30 m / s, which facilitates the formation of turbulence; the gauge pressure of the high-speed airflow ejected by the air supply mechanism 1 is preferably 0.05 to 0.6 MPa, specifically, it can be 0.05 MPa, 0.10 MPa, 0.15 MPa, 0.20 MPa, 0.35 MPa, 0.40 MPa, 0.45 MPa, 0.50 MPa, 0.55 MPa, or 0.6 MPa, etc. If the gauge pressure of the high-speed airflow is too low, the spinning solution cannot be fully sprayed and stretched by the high-speed airflow, making it difficult to form ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality. If the gauge pressure of the high-speed airflow is too high, the spinning solution jet is easily broken by the high-speed airflow, making it difficult to obtain ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality. Therefore, using the airflow gauge pressure of this application is beneficial for obtaining ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality.

[0150] In one embodiment of the present invention, activating the liquid supply mechanism 2 specifically includes controlling the speed at which the liquid supply mechanism 2 supplies the spinning solution to a value ranging from 0.5 mL / min to 10 mL / min. Specifically, the liquid supply speed of the liquid supply mechanism 2, ranging from 0.5 mL / min to 10 mL / min, can be 0.5 mL / min, 1.5 mL / min, 2.5 mL / min, 3.5 mL / min, 4.5 mL / min, 5.5 mL / min, 6.5 mL / min, 7.5 mL / min, 8.5 mL / min, 9.5 mL / min, or 10 mL / min, etc. If the liquid supply speed of the liquid supply mechanism 2 is too slow, the spinning solution remaining in the channel 311 on the roller unit 31 will easily dry up, reducing the preparation efficiency. Therefore, it is difficult to form ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality. If the liquid supply speed of the liquid supply mechanism 2 is too fast, too much spinning solution will remain in the channel 311 on the roller unit 31. Larger droplets will easily form during the spinning process, making it difficult to obtain ultrafine fibers with a large aspect ratio, uniform structure, and excellent quality.

[0151] The testing method of this invention includes:

[0152] Field emission scanning electron microscope (FE-SEM): LEO-1530, Zeiss, Germany.

[0153] Average Diameter and Average Bending Angle: The diameter and bending angle of 200 coiled microfibers were measured from at least 10 SEM images using Image Pro plus software (Media Cybernetics, USA), and the average value was calculated to obtain the average diameter and average bending angle of the coiled microfibers. The bending angle was measured as follows: Microfibers with a length greater than or equal to 20 μm were selected, and the tangent direction 'a' (vector) at the starting point and the tangent direction 'b' (vector) at the ending point of that length were measured. The deflection angle of tangent direction 'a' and tangent direction 'b' was recorded as the bending angle. Figure 38 As shown.

[0154] Breathability: ASTM D737, tested using a MOCON 3 / 33MA breathability tester from MOCON, Inc.

[0155] Water vapor transmission rate: GB / T 12704.2, using the YG(B)216T moisture permeability measuring instrument from Wuhan Bangning Intelligent Technology Co., Ltd.

[0156] Thermal conductivity: For the hot wire method in GB / T 10297, the TC3000E of Xi'an Xiaxi Technology Co., Ltd. shall be used; or for the flat plate method in GB / T 10294, the TC1100E of Xi'an Xiaxi Technology Co., Ltd. shall be used.

[0157] Static contact angle: No water droplet method, using Dataphysics OCA20 contact angle / surface tension measuring instrument from Germany.

[0158] Clo value: GB / T 18398 warm body dummy method, using Newton SN251 of Measurement Technology Northwest.

[0159] Porosity: X-ray ultrafine computed tomography scan using RX Solutions' EasyTom XL.

[0160] High-speed camera observation: The spinning process was directly observed using a high-speed camera (Os7, IDT Vision, USA) equipped with an F-mount lens (atx-i 100mm F2.8 FF MACRO, Tokina, Japan). A 100W LED light (LED-100-T, Visico, China) continuously illuminated the spinning area, enabling the high-speed camera to obtain clear images with short exposure times. All high-speed images were captured at 8000fps with a resolution of 1920×416px and an exposure time of 60μs. Analysis of the acquired videos was performed using Motion Studio software. All high-speed videos were played back at 24 frames per second, and images acquired at 8000fps were used.

[0161] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0162] The following will provide a detailed description of the high-crimp ultrafine fiber based on solution blown spinning technology and its preparation method, using specific implementation examples.

[0163] Examples 1-9 Polymer Crimped Microfibers

[0164] A method for preparing crimped ultrafine fibers, comprising spinning using the aforementioned spinning apparatus; specifically:

[0165] The structural parameters of the spinning device are as follows:

[0166] The inner diameter of the roller is 100mm and the wall thickness is 5mm. There are four circular spinning holes with a diameter of 1mm on the wall of the roller (the inside is a smooth wall surface). The four holes are arranged in a row (i.e., one row and four columns (1*4)) with a spacing of 1.2mm. The included angle between the central axes of adjacent holes is 1.37° when measured along the central axis of the holes.

[0167] The distance between the wall of the roller and the collecting net is 80cm.

[0168] The spinning process is as follows:

[0169] (1) Prepare the spinning solution: Dissolve the solute with mass m1 in the solvent with mass m2, stir at temperature t and stirring speed r until dissolved.

[0170] solute solvent m1(g) m2(g) t(℃) r(RPM) Example 1 PVB Anhydrous ethanol 5 95 room temperature 1000 Example 2 PAN DMF 12.5 87.5 60 1000 Example 3 PVDF-HFP DMC 7 93 room temperature 800 Example 4 PMMA DMF 22 78 60 1200 Example 5 PCL DCM 6 94 room temperature 600 Example 6 PLA DCM 4 96 room temperature 600 Example 7 PU Anhydrous ethanol 40 60 room temperature 1000 Example 8 PVP Anhydrous ethanol 9 91 room temperature 1000 Example 9 PAA DMF 9 91 40 1000

[0171] Taking Example 1 as an example, the process of preparing the spinning solution is as follows: 5g of PVB solid (CAS No.: 68648-78-2, molecular weight: 234) is dissolved in 95g of anhydrous ethanol, and the PVB spinning solution is prepared by rotating and stirring at 1000rpm for 5h at room temperature.

[0172] (2) Place the spinning solution prepared in step (1) into the liquid supply mechanism and start spinning; the spinning parameters of each embodiment are shown in the table below:

[0173]

[0174]

[0175] Taking Example 1 as an example, the spinning process is as follows:

[0176] The spinning solution prepared in step (1) is placed in the liquid supply mechanism, and the spinning solution is supplied at a rate of 3000 μL·min. -1 The spinning solution is forced into a rotating drum at a speed of 600 rad / min. At this time, the distance between the liquid guiding unit (conduit) and the drum is 1 mm, the distance between the outlet end of the air jet unit (nozzle) and the inner wall of the drum is 3 mm, the volume velocity of the air jet near the air jet unit (nozzle) is about 15 m / s, and the temperature is room temperature. This causes the spinning solution on the spinning drum to form fibers under the action of the airflow field and deposit them in a collection net 80 cm away from the spinning hole, thus obtaining crimped ultrafine fibers. Under the airflow jet state in Example 1, based on CFD simulation, the laminar flow section length of the airflow field is 1.71 mm.

[0177] The production process described above was monitored, and the parameters of the crimped microfibers prepared in each embodiment and the production efficiency of the corresponding embodiment are shown in the table below:

[0178]

[0179]

[0180] Under the above spinning process, the high-speed camera test results show that the straight section length of the spinning jet in Example 1 is 5.02 mm, that is, the ratio of the straight section length to the laminar flow section length falls within the range of 1.5 to 3.0, and the number of jets extending out from a single spinning hole is 3 to 6.

[0181] The coiled ultrafine fiber aggregates deposited in each embodiment have a porous structure.

[0182] Among them, such as Figures 15-18 As shown, the porosity of the PVB crimped ultrafine fiber aggregates obtained in Example 1 is as high as 99% or more, and the bulk density in the stable state after compression and rebound is 6.86 ± 0.12 mg / cm³. -3 Thermal conductivity is 27.60 mW - 1 m -1 K -1 It can withstand temperatures as low as -196℃. Its air permeability is as high as 54.82±18.15 mm² / s. -1 The moisture permeability is as high as 5625.43±68.51gm. -2 d -1 The clo value per unit thickness reaches 0.318 clo mm. -1 It is hydrophobic, with a contact angle with water reaching 136°.

[0183] A photograph of the PAN crimped ultrafine fiber aggregates obtained in Example 2 is shown below. Figure 20 As shown;

[0184] A photograph of the PMMA crimped ultrafine fiber aggregates obtained in Example 4 is shown below. Figure 23 As shown, its porosity is as high as 99.24%, and the material density is 8.71 ± 0.21 mg / cm³. -3 .

[0185] Example 10: Curled microfiber of material C

[0186] The PAN crimped microfibers obtained in Example 2 were placed in a muffle furnace and heated to 230°C at a rate of 5°C / min, then to 290°C at a rate of 1°C / min, and then carbonized at 1200°C for 1 hour at a rate of 5°C / min under a nitrogen atmosphere to obtain C-material crimped microfibers with a production efficiency of 0.78gh. -1 per1mm-hole.

[0187] The obtained C-material crimped microfibers were characterized, such as... Figures 29-30As shown, it was found that the average diameter of the C-material crimped microfiber is 256±73nm, the average bending angle is 218.18°, and the proportion of crimped microfiber with a bending angle greater than 90° reaches 85.2% of the total fiber volume. It can withstand high temperatures up to 2000℃.

[0188] Example 11: Curled microfibers made of Al2O3

[0189] A method for preparing crimped microfibers, using the same spinning apparatus as in Example 1, except that the distance between the wall of the roller and the collecting net is 90 cm.

[0190] The spinning process is as follows:

[0191] (1) Preparation of spinning solution: Mix 4g PVP, 12g aluminum chloride hexahydrate, 30g deionized water and 10g anhydrous ethanol, and stir at 800rpm at room temperature until clear to obtain spinning solution.

[0192] (2) Place the spinning solution prepared in step (1) into the liquid supply mechanism and start spinning; the spinning parameters are as follows: liquid supply rate 1000 μL·min -1 The rotational speed of the drum is 800 rad / min; the airflow pressure is 0.18 MPa; and the velocity of the airflow jet is 23 m / s.

[0193] Under the above spinning process, high-speed camera experiments showed that the straight-line jet length of each spinning solution was 6.06 mm, and the ratio of the straight-line length to the laminar flow length of the spinning jet formed by the spinning solution was greater than or equal to 2.5. The number of jets extending from a single spinning orifice was between 1 and 4. Monitoring the above production process, the production efficiency of the crimped ultrafine fibers obtained from the Al2O3 precursor was 11.39 gh. -1 / pore. A test image of the crimped ultrafine fibers of the Al2O3 precursor is shown below. Figure 31 As shown.

[0194] (3) Heat treatment: The crimped ultrafine fibers obtained in step (2) were placed in a muffle furnace and heated to 1100°C at a rate of 5°C / min, and held for 2 hours. Subsequently, Al2O3 crimped ultrafine fibers were obtained by natural cooling (based on the fiber mass at this time, the preparation efficiency was approximately 2.31gh). -1 / hole).

[0195] The obtained Al2O3 crimped ultrafine fibers were characterized, such as... Figure 32 As shown, the average diameter of the Al2O3 coiled microfiber is 256±73nm, the average bending angle is 146.21°, and the proportion of microfibers with a bending angle of more than 90° reaches 61.03%, which can withstand high temperatures of up to 1500℃.

[0196] Example 12: SiO2-coated ultrafine fibers carrying SiO2 aerosol powder

[0197] A method for preparing crimped microfibers, using the same spinning apparatus as in Example 1.

[0198] The spinning process is as follows:

[0199] (1) Preparation of spinning solution: Dissolve 4g PEO in 40g deionized water, add a magnetic stir bar, heat and magnetically stir at 60℃ for 1 hour to obtain polyethylene oxide (PEO) solution; then add 15.6g tetraethyl orthosilicate (TEOS, 99%) and 0.08g H3PO4 and 5g SiO2 aerogel powder as dispersed phase to the obtained polyethylene oxide (PEO) solution, and magnetically stir the solution at room temperature for 6h to obtain spinning solution.

[0200] (2) Place the spinning solution prepared in step (1) into the liquid supply mechanism and start spinning; the spinning parameters are as follows: liquid supply rate 1300 μL·min -1 The drum rotation speed is 250 rad / min; the airflow pressure is 0.15 MPa; and the airflow jet velocity is 20 m / s.

[0201] Under the above spinning process, the high-speed camera test results show that the ratio of the length of the straight section of the spinning jet formed by the spinning solution to the length of the laminar flow section is greater than or equal to 2.5, and the average diameter of the prepared crimped ultrafine fiber is mainly distributed in the range of 0.5 to 1.5 μm.

[0202] (3) Heat treatment: The crimped ultrafine fibers obtained in step (2) are placed in a muffle furnace and heated to 800°C at a rate of 5°C / min in an air atmosphere and held for 2 hours. Subsequently, the crimped ultrafine fibers carrying SiO2 aerosol powder are obtained by natural cooling.

[0203] The obtained crimped microfibers were characterized, such as... Figure 33 As shown, the diameter of the crimped microfibers is mainly distributed in the range of 200-800 nm, with an average bending angle of 101.21°. Microfibers with a bending angle of more than 90° account for 51.2%.

[0204] Example 13

[0205] A method for preparing crimped microfiber is basically the same as that in Example 1, except that the number of rows of spinning holes on the roller is 3.

[0206] Example 14

[0207] A method for preparing crimped microfiber is basically the same as that in Example 1, except that the number of rows of spinning holes on the roller is 2.

[0208] Example 15

[0209] A method for preparing crimped microfiber is basically the same as that in Example 1, except that the number of spinning holes on the roller is 1.

[0210] Based on CFD simulations, the lengths of the laminar flow sections formed by the spinning hole arrays in Examples 13, 14, and 15 are shown in the table below. High-speed camera experimental results show the ratio of the straight section length to the laminar flow section length of each spinning jet, as shown in the table below.

[0211] The parameters of the prepared crimped microfibers are shown in the table below:

[0212]

[0213]

[0214] As can be seen from the variation trends of the laminar flow section length and straight section length in Examples 1 and 13-15 above, for high-speed airflow, even a small disturbance can cause it to transform into turbulence. However, the development of high-speed airflow from a single spinning hole into turbulence requires a relatively long transition time. In contrast, when high-speed airflow interacts with the porous array of obstacles, multi-jet airflow is formed. The complex interactions within the multi-jet airflow usually accelerate the emergence of uniform turbulence, characterized by a significantly enhanced turbulence intensity and a gradually increasing ratio of straight section length to laminar flow section length. This invention utilizes a specifically arranged array of small holes, which not only reduces the long transition time required for airflow to develop into turbulence, but also forms multi-jet turbulence through turbulent mixing, strengthening the stretching and whipping of the spinning solution, and further promoting the formation of crimped ultrafine fibers. Furthermore, the preparation of crimped ultrafine fibers using the multi-jet turbulent section in this invention has universality and solves the problem of large-scale preparation of various crimped ultrafine fibers.

[0215] Example 16

[0216] A method for preparing crimped microfiber is basically the same as that in Example 1, except that the spinning steps are as follows:

[0217] (1) Preparation of spinning solution: Mix 4g PVP, 1.4g zirconium oxychloride octahydrate, 30g deionized water and 10g anhydrous ethanol, and stir at 1000rpm at room temperature until clear to obtain spinning solution.

[0218] (2) Place the spinning solution prepared in step (1) into the liquid supply mechanism and start spinning; the spinning parameters are as follows: liquid supply rate 1500 μL·min -1The drum rotation speed is 800 rad / min; the airflow pressure is 0.15 MPa; and the airflow jet velocity is 20 m / s.

[0219] Under the above spinning process, high-speed camera experiments showed that the straight-line jet length of each spinning solution was 5.76 mm, and the ratio of the straight-line length to the laminar flow length of the spinning jet formed by the spinning solution was greater than or equal to 2.5. The number of jets extending from a single spinning orifice was between 1 and 3. Monitoring the above production process, the production efficiency of the crimped ultrafine fibers obtained from the ZrO2 precursor was 2.08 gh. -1 / hole, its SEM image is as follows Figure 34 As shown.

[0220] (3) Heat treatment: The crimped ultrafine fibers obtained in step (2) were placed in a muffle furnace and heated to 800°C at a rate of 5°C / min, and held for 2 hours. Subsequently, ZrO2 crimped ultrafine fiber aggregates were obtained by natural cooling (based on the fiber mass at this time, the preparation efficiency was approximately 0.28gh). -1 / hole).

[0221] The obtained ZrO2 crimped ultrafine fiber aggregates were characterized, such as... Figure 35 As shown, the ZrO2 coiled microfiber has an average diameter of 101±55nm and an average bending angle of 116.67°. The proportion of microfibers with a bending angle of more than 90° reaches 58.8%, and it can withstand high temperatures of up to 1300℃.

[0222] Example 17

[0223] A method for preparing crimped microfiber is basically the same as in Example 1, except that the spinning steps are as follows:

[0224] (1) Preparation of spinning solution: Mix 4g PVP, 1.4g zirconium oxychloride octahydrate, 30g deionized water and 10g anhydrous ethanol, and stir at 1000rpm at room temperature until clear to obtain spinning solution.

[0225] (2) Place the spinning solution prepared in step (1) into the liquid supply mechanism and start spinning; the spinning parameters are as follows: liquid supply rate 1500 μL·min -1 The drum rotation speed is 800 rad / min; the airflow pressure is 0.10 MPa; and the airflow jet velocity is 14 m / s.

[0226] Under the above spinning process, high-speed camera experiments showed that the straight-line jet length of each spinning solution was 4.71 mm, and the ratio of the straight-line length to the laminar flow length of the spinning jet formed by the spinning solution was greater than or equal to 2.5. The number of jets extending from a single spinning orifice was 4 to 6. Monitoring the above production process, the production efficiency of the crimped ultrafine fibers obtained from the PI precursor was 1.45gh. -1 / hole.

[0227] (3) Heat treatment: The crimped microfibers obtained in step (2) were placed in a muffle furnace and heated to 300°C at a rate of 5°C / min, and held for 1 hour. Subsequently, PI crimped microfiber aggregates were obtained by natural cooling (based on the fiber mass at this time, the preparation efficiency was approximately 1.09gh). -1 / hole).

[0228] The obtained PI crimped microfibers were characterized, such as... Figure 36 As shown, the average diameter of the PI crimped microfiber is 150±65nm, the average bending angle is 147.17°, and the proportion of microfibers with a bending angle of more than 90° reaches 67.7%, which can withstand high temperatures of up to 400℃.

[0229] Comparative examples of PVB microfiber preparation using different spinning methods

[0230] The spinning solution from Example 1 was spun using electrospinning, pneumatic electrospinning, and pneumatic spinning, respectively.

[0231] The main parameters for electrospinning include: voltage 20kV, liquid supply rate 20μL·min. -1 The receiving distance is 80cm.

[0232] The main parameters for electrospinning include: voltage 10kV, airflow velocity 15m / s, and liquid supply rate 35μL·min. -1 The receiving distance is 80cm.

[0233] The main parameters for air spinning include: airflow velocity of 15 m / s and liquid supply rate of 50 μL·min. -1 The receiving distance is 80cm.

[0234] The ultrafine fibers prepared by the above spinning process were characterized respectively, such as Figure 37 As shown, the ultrafine fibers obtained in Example 1 of this invention are the most curled.

[0235] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultrafine fiber aggregate, prepared by solution blown spinning technology, characterized in that, include: Curled microfibers with a diameter of less than 1 μm and wherein the average bending angle of the curled microfibers is greater than or equal to 100°; The average bending angle is obtained by measuring the bending angle of 200 curled microfibers from no less than 10 SEM photos using Image Pro plus software and calculating the average value. The method for measuring the bending angle of a single crimped microfiber is as follows: Select a crimped microfiber with a length greater than or equal to 20 μm, and select a 20 μm length as the measurement segment; determine the first tangent direction at the starting point of the measurement segment; determine the second tangent direction at the ending point of the measurement segment; calculate the angle between the first tangent direction and the second tangent direction, and the angle is the bending angle of the microfiber.

2. The ultrafine fiber aggregate according to claim 1, characterized in that, In the microfiber aggregate, crimped microfibers with a bending angle of 90° or greater account for more than 50% of the total number of fibers.

3. The ultrafine fiber aggregate according to claim 2, characterized in that, In the microfiber aggregate, crimped microfibers with a bending angle of 90° or greater account for more than 60% of the total number of fibers.

4. The ultrafine fiber aggregate according to claim 1, characterized in that, The porosity of the ultrafine fiber aggregate is 90%~99.999%.

5. The ultrafine fiber aggregate according to any one of claims 1 to 4, characterized in that, The composition of the crimped microfiber includes one or more of the following: organic polymers, inorganic non-metals, and metals.

6. A method for preparing the ultrafine fiber aggregate according to any one of claims 1 to 5, characterized in that, include: It is prepared by solution blowing technology using spinning solution as raw material; The solution blown spinning technology includes: the spinning solution is ejected from the spinning hole by the action of air jet, and then stretched and whipped up and down by the action of airflow field; The airflow field includes a laminar flow section and a turbulent flow section, and the length of the straight section of the spinning jet formed by the spinning solution is greater than the length of the laminar flow section.

7. The method for preparing the ultrafine fiber aggregate according to claim 6, characterized in that, The ratio of the length of the straight section to the length of the laminar flow section of the spinning jet formed by the spinning solution is greater than or equal to 2.

8. The method for preparing the ultrafine fiber aggregate according to claim 7, characterized in that, The length of the laminar flow section is less than 5 mm.

9. The method for preparing the ultrafine fiber aggregate according to claim 7, characterized in that, The ratio of the length of the straight section to the length of the laminar flow section of the spinning jet formed by the spinning solution is greater than or equal to 2.

5.

10. The method for preparing the ultrafine fiber aggregate according to any one of claims 6 to 9, characterized in that, The length of the spinning hole along the central axis is 0.5 mm or more; the equivalent diameter of the cross-section of the spinning hole ranges from 0.2 mm to 2.0 mm.

11. The method for preparing the ultrafine fiber aggregate according to any one of claims 6 to 9, characterized in that, The feeding rate of the spinning solution is 0.5~10mL / min, the velocity of the air jet is 2~30m / s, and the receiving distance is 40cm or more.

12. The method for preparing the ultrafine fiber aggregate according to claim 10, characterized in that, The feeding rate of the spinning solution is 0.5~10mL / min, the velocity of the air jet is 2~30m / s, and the receiving distance is 40cm or more.

13. The method for preparing the ultrafine fiber aggregate according to claim 11, characterized in that, The airflow pressure is above 0.08 MPa.

14. The method for preparing the ultrafine fiber aggregate according to claim 12, characterized in that, The airflow pressure is above 0.08 MPa.

15. The method for preparing the ultrafine fiber aggregate according to any one of claims 6 to 9, characterized in that, The plurality of the aforementioned spinning holes are located on a needleless spinning mechanism; The spinning mechanism includes a hollow cylindrical roller with multiple through-holes formed on the side wall of the roller, which are the spinning holes.

16. The method for preparing the ultrafine fiber aggregate according to claim 10, characterized in that, The plurality of the aforementioned spinning holes are located on a needleless spinning mechanism; The spinning mechanism includes a hollow cylindrical roller with multiple through-holes formed on the side wall of the roller, which are the spinning holes.

17. The method for preparing the ultrafine fiber aggregate according to claim 11, characterized in that, The plurality of the aforementioned spinning holes are located on a needleless spinning mechanism; The spinning mechanism includes a hollow cylindrical roller with multiple through-holes formed on the side wall of the roller, which are the spinning holes.

18. The method for preparing the ultrafine fiber aggregate according to any one of claims 12 to 14, characterized in that, The plurality of the aforementioned spinning holes are located on a needleless spinning mechanism; The spinning mechanism includes a hollow cylindrical roller with multiple through-holes formed on the side wall of the roller, which are the spinning holes.

19. The method for preparing the ultrafine fiber aggregate according to claim 15, characterized in that, The channels are arranged in multiple rows along the circumference of the roller; the included angle between two adjacent rows of channels ranges from 0.5° to 2°; the distance between two adjacent channels is less than 1.2 mm.

20. The method for preparing the ultrafine fiber aggregate according to claim 16 or 17, characterized in that, The channels are arranged in multiple rows along the circumference of the roller; the included angle between two adjacent rows of channels ranges from 0.5° to 2°; the distance between two adjacent channels is less than 1.2 mm.

21. The method for preparing the ultrafine fiber aggregate according to claim 18, characterized in that, The channels are arranged in multiple rows along the circumference of the roller; the included angle between two adjacent rows of channels ranges from 0.5° to 2°; the distance between two adjacent channels is less than 1.2 mm.

22. The method for preparing the ultrafine fiber aggregate according to claim 15, characterized in that, The porosity of the roller wall ranges from 40% to 99.9%.

23. The method for preparing the ultrafine fiber aggregate according to any one of claims 16, 17, 19, and 21, characterized in that, The porosity of the roller wall ranges from 40% to 99.9%.

24. The method for preparing the ultrafine fiber aggregate according to claim 18, characterized in that, The porosity of the roller wall ranges from 40% to 99.9%.

25. The method for preparing the ultrafine fiber aggregate according to claim 20, characterized in that, The porosity of the roller wall ranges from 40% to 99.9%.

26. The method for preparing the ultrafine fiber aggregate according to claim 15, characterized in that, The linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

27. The method for preparing the ultrafine fiber aggregate according to any one of claims 16, 17, 19, 21, 24-25, characterized in that, The linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

28. The method for preparing the ultrafine fiber aggregate according to claim 18, characterized in that, The linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

29. The method for preparing the ultrafine fiber aggregate according to claim 20, characterized in that, The linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

30. The method for preparing the ultrafine fiber aggregate according to claim 23, characterized in that, The linear velocity of the roller ranges from 0.1 m / s to 10 m / s.

31. The method for preparing the ultrafine fiber aggregate according to claim 15, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

32. The method for preparing the ultrafine fiber aggregate according to claim 18, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

33. The method for preparing the ultrafine fiber aggregate according to claim 20, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

34. The method for preparing the ultrafine fiber aggregate according to claim 23, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

35. The method for preparing the ultrafine fiber aggregate according to claim 27, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

36. The method for preparing the ultrafine fiber aggregate according to any one of claims 16, 17, 19, 21, 24-26, 28-30, characterized in that, At least one protrusion is provided on the inner wall surface of the channel, and the height of the protrusion is less than the equivalent radius of the channel cross-section when measured along the cross-sectional direction of the channel.

37. The use of the ultrafine fiber aggregate prepared by any one of claims 1 to 5 or any one of claims 6 to 36 in adsorption, conduction and barrier applications.

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