Antistatic agent, polyurethane nanofiber membrane and preparation method of polyurethane nanofiber membrane

Abstract

The invention relates to an antistatic agent, a polyurethane nanofiber membrane and a preparation method of the polyurethane nanofiber membrane, and the antistatic agent comprises the following components in parts by weight: 60-90 parts of acetate ionic liquid, 5-20 parts of mesylate ionic liquid and 5-20 parts of dicyandiamide salt ionic liquid. When the antistatic agent composed of the three ionic liquids is added into an electrostatic spinning solution, the conductivity of the electrostatic spinning solution can be remarkably improved, the problem of insufficient stability in the electrostatic spinning process is effectively solved, meanwhile, bead formation in the spinning process is inhibited, and finally the polyurethane nanofiber membrane with regular morphology and uniform fiber diameter is prepared. The polyurethane nanofiber membrane has no pinhole defect and is uniform in pore size and distribution, so that the polyurethane nanofiber membrane can be endowed with excellent waterproof performance and air permeability, and the core use requirements of functional textiles on the waterproof and air-permeable membrane are met.

Description

Technical Field

[0001] This invention relates to the field of thin film materials technology, and in particular to antistatic agents, polyurethane nanofiber membranes, and their preparation methods. Background Technology

[0002] The preparation of traditional high-performance waterproof and breathable membranes generally relies on complex processes such as phase separation and biaxial stretching. The membrane materials prepared by such processes often have inherent defects such as uneven pore size distribution, low porosity, and non-penetrating membrane pore structure, which directly limit the further improvement of the overall performance of the membrane materials. At the same time, it increases the difficulty of production cost control and cannot meet the application requirements of industrial scale and high performance.

[0003] In contrast, electrospinning, as a direct, efficient, and precisely controllable nanofiber preparation technology, provides a new technical path for the preparation of high-performance waterproof and breathable membranes. This technology can directly prepare three-dimensional network structure membranes with fiber diameters ranging from tens to hundreds of nanometers, interconnected pores, and extremely high porosity. Theoretically, this three-dimensional network structure can simultaneously achieve efficient water vapor permeation and effective blocking of liquid water, solving the technical challenge of traditional membrane materials that struggle to balance breathability and waterproof performance.

[0004] Therefore, electrospinning is a preferred method for preparing polyurethane (PU) nanofiber membranes, bypassing the technological barriers of traditional preparation processes and achieving precise membrane structure design and comprehensive performance optimization. To ensure the durable waterproof performance of polyurethane nanofiber membranes, traditional electrospinning methods typically require the addition of hydrophobic agents and LiF as modifiers. LiF, as an antistatic agent, is mainly used to increase the conductivity of the electrospinning solution, ensuring a continuous, stable, and reliable spinning process. However, LiF, as a fluoride, is chemically stable, difficult to degrade in the natural environment, and easily accumulates in organisms, posing potential hazards to ecosystems and human health with long-term use. Therefore, finding novel materials to replace the traditional antistatic agent LiF in electrospinning has become a critical technical problem urgently needing to be solved in the current electrospinning preparation of polyurethane nanofiber membranes. Summary of the Invention

[0005] Therefore, it is necessary to provide an antistatic agent, a polyurethane nanofiber membrane, and a method for preparing the above-mentioned problems. The antistatic agent can significantly improve the conductivity of the electrospinning solution, solve the instability problem in the electrospinning process, inhibit bead formation, and finally obtain a polyurethane nanofiber membrane with regular morphology and uniform diameter.

[0006] An antistatic agent, by mass parts, comprises 60 to 90 parts of acetate ionic liquid, 5 to 20 parts of methanesulfonate ionic liquid, and 5 to 20 parts of dicyandiamide ionic liquid.

[0007] In one embodiment, the organic cation of the acetate ionic liquid is selected from imidazole cations;

[0008] And / or, the organic cation of the methanesulfonate ionic liquid is selected from imidazole cations;

[0009] And / or, the organic cation of the dicyandiamide salt ionic liquid is selected from imidazole cations.

[0010] In one embodiment, the acetate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-hexyl-3-methylimidazolium acetate, 1-octyl-3-methylimidazolium acetate, and 1-allyl-3-methylimidazolium acetate.

[0011] In one embodiment, the methanesulfonate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methanesulfonate, 1-hexyl-3-methylimidazolium methanesulfonate, 1-butyl-2,3-dimethylimidazolium methanesulfonate, and 1-octyl-3-methylimidazolium methanesulfonate.

[0012] In one embodiment, the dicyandiamide salt ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium dicyandiamide, 1-butyl-3-methylimidazolium dicyandiamide, 1-hexyl-3-methylimidazolium dicyandiamide, 1-octyl-3-methylimidazolium dicyandiamide, and 1-butyl-2,3-dimethylimidazolium dicyandiamide.

[0013] A method for preparing a polyurethane nanofiber membrane includes the following steps:

[0014] An electrospinning solution was prepared by adding polyurethane, a hydrophobic modifier, and the aforementioned antistatic agent to an organic solvent.

[0015] Polyurethane nanofiber membranes were prepared by electrospinning using the electrospinning solution as raw material.

[0016] In one embodiment, the mass ratio of the polyurethane to the hydrophobic modifier is 1:0.625~1.5;

[0017] And / or, the mass ratio of the polyurethane to the antistatic agent is 1:0.0125~0.0625;

[0018] And / or, the mass ratio of the polyurethane to the organic solvent is 1:10~10.875.

[0019] In one embodiment, the hydrophobic modifier is selected from one or more of paraffins, organosilicones, and isocyanates;

[0020] And / or, the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, and dichloromethane.

[0021] In one embodiment, during the electrospinning step, the voltage parameters are 10kV~85kV, the liquid pushing speed is 0.5mL / h~10mL / h, the receiving distance is 15cm~30cm, the winding speed is 50rpm~100rpm, the temperature is 15℃~30℃, and the humidity is 40%~60%.

[0022] A polyurethane nanofiber membrane obtained by the preparation method described above.

[0023] The antistatic agent composed of three ionic liquids in this invention, when added to the electrospinning solution, can significantly improve the conductivity of the electrospinning solution, thereby effectively improving the problem of insufficient stability during electrospinning. Simultaneously, it inhibits the formation of beads during spinning, ultimately producing a polyurethane nanofiber membrane with regular morphology and uniform fiber diameter. This polyurethane nanofiber membrane is free of pinhole defects and has a uniform pore size and distribution, thus endowing it with excellent waterproof and breathable properties, meeting the core requirements of functional textiles for waterproof and breathable membranes. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a visual representation of the polyurethane nanofiber membrane obtained in Example 1 of the present invention.

[0026] Figure 2 This is a microscopic scanning image of the polyurethane nanofiber membrane obtained in Example 1 of the present invention;

[0027] Figure 3 This is a visual representation of the polyurethane nanofiber membrane obtained in Example 2 of the present invention.

[0028] Figure 4 This is a visual representation of the polyurethane nanofiber membrane obtained in Comparative Example 1 of the present invention.

[0029] Figure 5 This is a microscopic scanning image of the polyurethane nanofiber membrane obtained in Comparative Example 1 of the present invention.

[0030] Figure 6 This is a visual representation of the polyurethane nanofiber membrane obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0031] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0033] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0034] The antistatic agent provided by the present invention comprises 60 to 90 parts by weight of acetate ionic liquid, 5 to 20 parts by weight of methanesulfonate ionic liquid and 5 to 20 parts by weight of dicyandiamide ionic liquid.

[0035] The antistatic agent of this invention can be applied in the fields of functional material modification, polymer material processing, and textile fiber preparation, and is preferably applied in the field of electrospinning, and more preferably in the preparation of polyurethane nanofiber membranes by electrospinning. Specifically, it can be used to modify the spinning solution for preparing polyurethane nanofiber membranes by electrospinning, adapt to the electrospinning process of various polyurethane substrates, provide antistatic support for the preparation of high-performance and environmentally friendly polyurethane nanofiber membranes, and thus expand the application of polyurethane nanofiber membranes in end fields such as functional textiles, protective equipment, and medical materials.

[0036] Specifically, since ionic liquids contain both cations and anions, different types of anions have different effects on improving conductivity. The three ionic liquids of this invention contain acetate, methanesulfonate, and dicyandiamide ions, respectively. When added to the electrospinning solution of polyurethane, the ions undergo directional migration under the action of an external electric field, forming a current, which can significantly improve the conductivity of the electrospinning solution. This effectively improves the problem of insufficient electric field stability during electrospinning and inhibits the formation of beads during spinning, ultimately preparing a polyurethane nanofiber membrane with regular morphology and uniform fiber diameter.

[0037] It should be noted that the mass ratio of the three ionic liquids in this invention needs to be controlled within a certain range. Exceeding this range will result in crystal precipitation of the prepared antistatic agent, leading to a short effective time for the electrospinning solution, poor coagulation and spinnability, and more seriously, large-area unevenness in the thickness of the electrospun film. In contrast, the polyurethane nanofiber membrane prepared by this invention in the appropriate ratio is free of pinhole defects, has a uniform pore size and distribution, and thus endows the polyurethane nanofiber membrane with excellent waterproof and breathable properties, meeting the core requirements of functional textiles for waterproof and breathable membranes.

[0038] The selection range of organic cations for acetate ionic liquids, methanesulfonate ionic liquids, and dicyandiamide ionic liquids is relatively wide. For example, imidazole, pyridine, pyrrolidine, and piperidine organic cations can be used. Considering the conductivity of organic cations, their compatibility with polyurethane spinning solutions, and their suitability for electrospinning processes and the final fiber membrane properties, imidazole organic cations are preferred. These organic cations have good conductivity and structural tunability, better balancing antistatic properties with spinning process compatibility, ensuring stable spinning processes and excellent overall performance of the polyurethane nanofiber membrane. Therefore, the organic cations of the acetate ionic liquids, methanesulfonate ionic liquids, and dicyandiamide ionic liquids are selected from imidazole cations.

[0039] In some embodiments, the acetate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-hexyl-3-methylimidazolium acetate, 1-octyl-3-methylimidazolium acetate, and 1-allyl-3-methylimidazolium acetate.

[0040] In some embodiments, the methanesulfonate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methanesulfonate, 1-hexyl-3-methylimidazolium methanesulfonate, 1-butyl-2,3-dimethylimidazolium methanesulfonate, and 1-octyl-3-methylimidazolium methanesulfonate.

[0041] In some embodiments, the dicyandiamide salt ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium dicyandiamide, 1-butyl-3-methylimidazolium dicyandiamide, 1-hexyl-3-methylimidazolium dicyandiamide, 1-octyl-3-methylimidazolium dicyandiamide, and 1-butyl-2,3-dimethylimidazolium dicyandiamide.

[0042] The antistatic agent of the present invention can be obtained by physically mixing according to the above proportions. In order to better improve the effect of the antistatic agent, the acetate ionic liquid, methanesulfonate ionic liquid and dicyandiamide ionic liquid are preferably purified to further remove impurities such as salts.

[0043] This invention also provides a method for preparing a polyurethane nanofiber membrane, comprising the following steps:

[0044] S1, an electrospinning solution is prepared by adding polyurethane, a hydrophobic modifier, and the antistatic agent into an organic solvent;

[0045] S2, using the electrospinning solution as raw material, a polyurethane nanofiber membrane is prepared by electrospinning.

[0046] The mass ratio of the polyurethane to the antistatic agent is 1:0.0125~0.0625. Therefore, by using the antistatic agent and controlling its proportion, the problem of insufficient stability during electrospinning can be effectively improved, while the formation of beads during spinning is suppressed, ultimately resulting in a polyurethane nanofiber membrane with regular morphology and uniform fiber diameter.

[0047] To ensure good compatibility between the hydrophobic modifier and polyurethane, achieve excellent hydrophobic modification effects, and simultaneously adapt to the electrospinning process while guaranteeing the overall performance of the final polyurethane nanofiber membrane, the hydrophobic modifier is selected from one or more of paraffin waxes, organosilicon compounds, and isocyanates. Isocyanates, in particular, can form stable covalent bonds with the polyurethane molecular chains and offer a combination of hydrophobicity, water resistance, mechanical strength, antistatic properties, and breathability. Therefore, isocyanates, such as hexamethylene diisocyanate, are further preferred as the hydrophobic modifier. Furthermore, the mass ratio of the polyurethane to the hydrophobic modifier is preferably controlled at 1:0.625~1.5.

[0048] In some embodiments, the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, and dichloromethane, more preferably N,N-dimethylformamide and / or N,N-dimethylacetamide, and even more preferably N,N-dimethylacetamide. Meanwhile, the mass ratio of the polyurethane to the organic solvent is controlled to be 1:10 to 10.875.

[0049] To ensure the stable operation of the electrospinning process, suppress bead formation, and ensure that the spinning solution can be successfully formed into fibers with regular morphology and uniform pore size, while adapting to the polyurethane spinning system and hydrophobic modification requirements, and ensuring the excellent comprehensive performance of the final polyurethane nanofiber membrane, the electrospinning steps include the following parameters: voltage parameters of 10kV~85kV, liquid pushing speed of 0.5mL / h~10mL / h, receiving distance of 15cm~30cm, winding speed of 50rpm~100rpm, temperature of 15℃~30℃, and humidity of 40%~60%.

[0050] The present invention also provides a polyurethane nanofiber membrane obtained by the preparation method described above, wherein the thickness of the polyurethane nanofiber membrane is preferably 25μm~40μm, and it has both excellent waterproof and breathable properties.

[0051] The technical solution of the present invention will be further described below through specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products.

[0052] Example 1

[0053] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate and 10 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0054] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain an electrospinning solution.

[0055] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0056] Figure 1 This is a visual representation of the polyurethane nanofiber membrane in this embodiment. Figure 1 It can be seen that the obtained fiber membrane has a smooth surface and no pinhole defects. Figure 2 This is a microscopic scanning image of the polyurethane nanofiber membrane in this embodiment. Figure 2 It can be seen that the fiber diameter is uniform, the pores are interconnected and the pore size distribution is uniform.

[0057] Example 2

[0058] By weight, 70 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of purified 1-butyl-3-methylimidazolium methanesulfonate, and 20 parts of purified 1-butyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0059] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain an electrospinning solution.

[0060] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 6 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0061] Figure 3 This is a diagram of the polyurethane nanofiber membrane in this embodiment. Figure 3 It can be seen that the surface of the obtained fiber membrane is smooth and free of pinhole defects.

[0062] Example 3

[0063] By weight, 60 parts of purified 1-hexyl-3-methylimidazolium acetate, 20 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate, and 20 parts of purified 1-butyl-3-methylimidazolium dicyanamide were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0064] A solution was prepared by mixing polyurethane, polydimethylsiloxane and N,N-dimethylformamide in a mass ratio of 8:5:87. Then, the above-mentioned antistatic agent, accounting for 5‰ of the total mass of the spinning solution, was added and stirred evenly to obtain an electrospinning solution.

[0065] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 40 kV, the liquid pushing speed at 4 mL / h, the receiving distance at 25 cm, the winding speed at 80 rpm, the temperature maintained at 28 °C, and the humidity at 45%, resulting in a polyurethane nanofiber membrane with a thickness of 30 μm.

[0066] Example 4

[0067] By weight, 75 parts of purified 1-butyl-3-methylimidazolium acetate, 15 parts of purified 1-octyl-3-methylimidazolium methanesulfonate, and 10 parts of purified 1-ethyl-3-methylimidazolium dicyanamide were stirred and mixed at 25°C for 1.5 h to obtain an antistatic agent.

[0068] A solution was prepared by mixing polyurethane, microcrystalline wax, and dichloromethane / N,N-dimethylformamide (mass ratio 1:1) in a mass ratio of 8:9:83. Then, the above-mentioned antistatic agent, accounting for 3‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0069] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 30 kV, the liquid pushing speed at 5 mL / h, the receiving distance at 22 cm, the winding speed at 70 rpm, the temperature maintained at 30 °C, and the humidity at 40%, resulting in a polyurethane nanofiber membrane with a thickness of 35 μm.

[0070] Example 5

[0071] By weight, 90 parts of purified 1-octyl-3-methylimidazolium acetate, 5 parts of purified 1-octyl-3-methylimidazolium methanesulfonate, and 5 parts of purified 1-octyl-3-methylimidazolium dicyanamide were stirred and mixed at 25°C for 1.5 h to obtain an antistatic agent.

[0072] A solution was prepared by mixing polyurethane, isocyanate-based hydrophobic modifier (isophorone diisocyanate), and N,N-dimethylacetamide / acetone (mass ratio 1:1) at a mass ratio of 8:12:80. Then, the above-mentioned antistatic agent, accounting for 5‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0073] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 50 kV, the liquid pushing speed at 2 mL / h, the receiving distance at 18 cm, the winding speed at 85 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 35 μm.

[0074] Comparative Example 1

[0075] By weight, 40 parts of purified 1-butyl-3-methylimidazolium acetate, 30 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate and 30 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0076] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0077] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0078] Figure 4 This is a visual representation of the polyurethane nanofiber membrane used in this comparative example. Figure 4 It can be seen that the surface of the obtained fiber membrane has a large number of pinhole defects. Figure 5 This is a microscopic scanning image of the polyurethane nanofiber membrane in this comparative example, from... Figure 5 It can be seen that the obtained fibers have uneven diameters, disordered pore size distribution, and poor pore connectivity.

[0079] Comparative Example 2

[0080] By weight, 80 parts of purified 1-butyl-3-methylimidazolium hydrogen sulfate, 10 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate, and 10 parts of purified 1-ethyl-3-methylimidazolium dicyanamide were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0081] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0082] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0083] Figure 6 This is a visual representation of the polyurethane nanofiber membrane used in this comparative example. Figure 6 It can be seen that there are a large number of pinhole defects on the surface of the obtained fiber membrane.

[0084] Comparative Example 3

[0085] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of sodium methanesulfonate, and 10 parts of purified 1-ethyl-3-methylimidazolium dicyandiamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0086] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0087] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0088] Comparative Example 4

[0089] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate, and 10 parts of purified sodium dicyandiamide were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0090] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0091] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0092] Comparative Example 5

[0093] By weight, 80 parts of purified 1-ethyl-3-methylimidazolium sulfate diethyl ester salt, 10 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate salt and 10 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0094] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0095] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0096] Comparative Example 6

[0097] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of purified 1-butyl-3-methylimidazolium thiocyanate and 10 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0098] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0099] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0100] Comparative Example 7

[0101] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate, 10 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate and 10 parts of purified 1-decyl-3-methylimidazolium bromide were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0102] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0103] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0104] Comparative Example 8

[0105] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate and 20 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0106] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0107] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0108] Comparative Example 9

[0109] By weight, 80 parts of purified 1-butyl-3-methylimidazolium acetate and 20 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0110] A solution was prepared by mixing polyurethane, isocyanate-based hydrophobic modifier, and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain an electrospinning solution.

[0111] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0112] Comparative Example 10

[0113] By weight, 50 parts of purified 1-ethyl-3-methylimidazolium methanesulfonate and 50 parts of purified 1-ethyl-3-methylimidazolium dicyanamide salt were stirred and mixed at 30°C for 1 hour to obtain an antistatic agent.

[0114] A solution was prepared by mixing polyurethane, hexamethylene diisocyanate and N,N-dimethylacetamide in a mass ratio of 8:10:82. Then, the above-mentioned antistatic agent, accounting for 1‰ of the total mass of the spinning solution, was added and stirred evenly to obtain the electrospinning solution.

[0115] Polyurethane nanofiber membranes were prepared by electrospinning, with the voltage controlled at 35 kV, the liquid pushing speed at 3 mL / h, the receiving distance at 20 cm, the winding speed at 90 rpm, the temperature maintained at 25 °C, and the humidity at 50%, resulting in a polyurethane nanofiber membrane with a thickness of 25 μm.

[0116] The polyurethane nanofiber membranes prepared in Examples 1 to 5 and Comparative Examples 1 to 10 were subjected to performance tests, and the results are shown in Table 1.

[0117] Table 1

[0118]

[0119] Compared to Example 1, Comparative Example 1 had an unbalanced ratio, with too low a proportion of acetate ionic liquid and too high proportions of methanesulfonate and dicyandiamide ionic liquids. This resulted in a 12% decrease in the conductivity of the spinning solution, an increase in the number of fiber membrane beads, a drop in the waterproof rating from level 5 to level 4, a 6.4% decrease in hydrostatic pressure, a 9.9% decrease in tensile strain, and a 25% decrease in moisture permeability. This was mainly because the antistatic agent, exceeding the specified ratio, would precipitate as a solid after a period of time, leading to a short effective period for the electrospinning solution, resulting in poor agglomeration and spinnability. Furthermore, electrostatic shielding would cause uneven electric field, leading to large-area unevenness in the thickness of the electrospun film, thus degrading the various properties of the prepared polyurethane film. This demonstrates that the antistatic agent composition must be within the ratio range of this invention to synergistically exert its optimal conductivity, fiber-forming, and reinforcing effects.

[0120] Compared with Example 1, Comparative Example 2 showed a 13% increase in conductivity, but the acetate ionic liquid was replaced with 1-butyl-3-methylimidazolium hydrogen sulfate ionic liquid. The anion had poor compatibility with PU, resulting in embrittlement of the fiber membrane, a 21% decrease in tensile strain, and severe wrinkling of the membrane surface.

[0121] Comparative Examples 3 and 4 replaced the methanesulfonate-based ionic liquid and the dicyandiamide-based ionic liquid with sodium methanesulfonate and sodium dicyandiamide, respectively, resulting in a decrease in conductivity, hydrostatic pressure, and tensile strength. This is because replacing them with solid salts reduces the number of conductive ions, leading to a decrease in conductivity. Furthermore, the presence of solid salts causes pinhole defects in the film. This demonstrates that ionic liquids are irreplaceable in improving conductivity and the density of fiber membranes.

[0122] Compared to Example 1, Comparative Example 5 showed similar conductivity, but its fiber membrane exhibited insufficient hydrophobicity, with a 21.8% decrease in hydrostatic pressure, demonstrating the crucial role of acetate ionic liquids in enhancing the hydrophobicity of the fiber surface. Comparative Examples 6 and 7, compared to Example 1, showed decreased conductivity, waterproof rating, and moisture permeability, proving the unique contribution of methanesulfonate and dicyandiamide ionic liquids to the membrane's waterproof and breathable properties. Comparative Examples 8-10 demonstrated that regardless of the missing component, the fiber membrane exhibited at least two key performance degradations (conductivity <65 μs / cm, waterproof rating ≤3, tensile strength <17 MPa, and moisture permeability <2.5 × 10⁻⁶). 4 Therefore, the ternary complex system of acetate ionic liquids, methanesulfonate ionic liquids, and dicyandiamide ionic liquids has a superior synergistic effect, and none of them can be omitted.

[0123] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An antistatic agent, characterized in that, The antistatic agent comprises, by weight, 60 to 90 parts of acetate ionic liquid, 5 to 20 parts of methanesulfonate ionic liquid, and 5 to 20 parts of dicyandiamide ionic liquid.

2. The antistatic agent according to claim 1, characterized in that, The organic cations of the acetate ionic liquid are selected from imidazole cations; And / or, the organic cation of the methanesulfonate ionic liquid is selected from imidazole cations; And / or, the organic cation of the dicyandiamide salt ionic liquid is selected from imidazole cations.

3. The antistatic agent according to claim 1 or 2, characterized in that, The acetate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-hexyl-3-methylimidazolium acetate, 1-octyl-3-methylimidazolium acetate, and 1-allyl-3-methylimidazolium acetate.

4. The antistatic agent according to claim 1 or claim 2, characterized in that, The methanesulfonate ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methanesulfonate, 1-hexyl-3-methylimidazolium methanesulfonate, 1-butyl-2,3-dimethylimidazolium methanesulfonate, and 1-octyl-3-methylimidazolium methanesulfonate.

5. The antistatic agent according to claim 1 or claim 2, characterized in that, The dicyandiamide salt ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium dicyandiamide, 1-butyl-3-methylimidazolium dicyandiamide, 1-hexyl-3-methylimidazolium dicyandiamide, 1-octyl-3-methylimidazolium dicyandiamide, and 1-butyl-2,3-dimethylimidazolium dicyandiamide.

6. A method for preparing a polyurethane nanofiber membrane, characterized in that, Includes the following steps: An electrospinning solution is prepared by adding polyurethane, a hydrophobic modifier, and an antistatic agent as described in any one of claims 1 to 5 into an organic solvent. Polyurethane nanofiber membranes were prepared by electrospinning using the electrospinning solution as raw material.

7. The method for preparing the polyurethane nanofiber membrane according to claim 6, characterized in that, The mass ratio of the polyurethane to the hydrophobic modifier is 1:0.625~1.5; And / or, the mass ratio of the polyurethane to the antistatic agent is 1:0.0125~0.0625; And / or, the mass ratio of the polyurethane to the organic solvent is 1:10~10.

875.

8. The method for preparing the polyurethane nanofiber membrane according to claim 6, characterized in that, The hydrophobic modifier is selected from one or more of paraffins, organosilicones, and isocyanates; And / or, the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, and dichloromethane.

9. The method for preparing a polyurethane nanofiber membrane according to claim 6, characterized in that, In the electrospinning step, the voltage parameters are 10kV~85kV, the liquid pushing speed is 0.5mL / h~10mL / h, the receiving distance is 15cm~30cm, the winding speed is 50rpm~100rpm, the temperature is 15℃~30℃, and the humidity is 40%~60%.

10. A polyurethane nanofiber membrane obtained by the preparation method according to any one of claims 6 to 9.

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