A method for preparing superhydrophobic electrospun membrane

Abstract

This application discloses a method for preparing a superhydrophobic electrospun film, relating to the field of textile and apparel technology. The method includes a raw material composition and an electrospinning component. The raw material composition involves selecting a formulation and preparing a polymer resin, then pulverizing the polymer resin to obtain a modified resin powder. The electrospinning component involves heating and melting the modified resin powder to obtain molten resin, then electrospinning the molten resin under a high-voltage electric field to form a superhydrophobic film layer on the mold surface. Finally, after cooling with cooling water, the film is unmolded and packaged to obtain the finished superhydrophobic electrospun film. The formulation composition includes 10-30 parts by weight of polyurethane (PU), 5-10 parts of polyamide 6, 3-6 parts of modified nano-silica, and 1-2 parts of polyetherimide. This application yields an electrospun film with superhydrophobic properties and good breathability, effectively improving the durability and protective properties of clothing fabrics.

Description

Technical Field

[0001] This application relates to the field of textile and apparel technology, and in particular to a method for preparing a superhydrophobic electrospun film. Background Technology

[0002] Hydrophobicity is defined as the phenomenon that a liquid does not wet a solid surface when the contact angle θ is greater than 90°. Materials with a stable contact angle θ greater than 150° and a rolling contact angle α less than 10° are classified as superhydrophobic materials.

[0003] The two factors that determine the superhydrophobic properties of a material are the surface roughness of the solid material and the chemical composition of the material. Therefore, there are two ways to prepare superhydrophobic materials: (1) modifying the surface of a rough structure with low surface energy materials. (2) constructing an appropriate rough structure on the surface of a material with low surface energy.

[0004] Electrospinning is a method in which a polymer solution or melt is sprayed and solidified into fibers under an applied electric field. Fibers prepared by electrospinning have both a large specific surface area and a unique microporous structure, characterized by high porosity.

[0005] However, the waterproof performance of clothing fabrics based on existing waterproof and breathable technologies gradually declines with the number of washes, which affects the garment's usability. Furthermore, clothing fabrics designed to achieve waterproof and breathable effects are typically made into rain jackets or ski suits, which is costly. Once the effectiveness declines, it affects the consumer's wearing experience, and in extremely cold environments, it can even lead to the loss of the garment's original protective properties, posing a life-threatening risk to consumers. Therefore, improvements are needed. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a method for preparing a superhydrophobic electrospun membrane to achieve the goal of maintaining long-lasting and effective waterproof and breathable properties. The specific solution is as follows:

[0007] A method for preparing a superhydrophobic electrospun film includes a raw material component and an electrospinning component;

[0008] The raw material consists of a selected formulation and a polymer resin prepared by further processing the polymer resin into powder to obtain modified resin powder.

[0009] The electrospinning process involves heating and melting modified resin powder to obtain molten resin, then electrospinning the molten resin through a high-voltage electric field to form a superhydrophobic film layer on the mold surface. Finally, the film is cooled with cooling water, removed from the mold, and packaged to obtain the finished superhydrophobic electrospinned film.

[0010] in:

[0011] The formulation comprises 10-30 parts by weight of PU polyurethane, 5-10 parts of polyamide 6, 3-6 parts of modified nano-silica, and 1-2 parts of polyetherimide; and the modification preparation method of the modified nano-silica includes step ① dispersing nano-silica in a 1-3% hydrochloric acid solution, controlling the temperature of the hydrochloric acid solution at 20-80℃, shaking and washing with water to obtain hydroxylated silica; step ② dispersing hydroxylated silica in isopropanol and / or diethyl ether, then adding dimethylaminoethyl acetate to the isopropanol and / or diethyl ether, and reacting with a catalyst to obtain dimethylaminoethyl silica; step ③ adding caprolactam to dimethylaminoethyl silica to react and obtain caprolactam polymerized silica; step ④ mixing and polymerizing caprolactam polymerized silica with caprolactam to obtain polyamide 6 grafted modified nano-silica.

[0012] Preferably, in step ②, the dimethylaminoethyl acetate is added dropwise, and the molar ratio of the dimethylaminoethyl acetate to the hydroxylated silica is 2-5:1.

[0013] Preferably, in step ②, the catalyst is an organic bismuth catalyst, and the organic bismuth catalyst is preferably one or a mixture of bismuth neodecanoate, bismuth stearate, bismuth tetradecanoate, and bismuth eicosate.

[0014] Preferably, in step ③, the caprolactam is added dropwise, and the mass ratio of caprolactam to the hydroxylated silica is 100:4-25.

[0015] Preferably, in step ③, the reaction temperature is 50-80℃ and the reaction time is 1-5h.

[0016] Preferably, in step ④, the polymerization reaction temperature is 150-220℃ and the reaction time is 2-3h.

[0017] Preferably, a metal oxide catalyst is added to the polymerization reaction, and the reaction temperature is 150-160℃.

[0018] Preferably, the powdering process includes grinding using a planetary ball mill, controlling the diameter of the grinding agate balls to be 4-12 mm, and the grinding time to be 0.5-1 h.

[0019] Preferably, the planetary ball mill is filled with an additive accounting for 0.1-1 wt% of the polymer resin, and the additive is at least one of TiO2, ZnO, Al2O3, and Fe2O3.

[0020] Preferably, the voltage of the high-voltage electric field is 3-100kV; the receiving distance is 5-40cm; and the feed flow rate of the molten resin is 0.2-4mL / h.

[0021] As can be seen from the above scheme, this application provides a method for preparing a superhydrophobic electrospun membrane. The superhydrophobic electrospun membrane prepared by this method using electrospinning and corresponding components exhibits an initial water pressure (ISO811, 60 cm / min) ≥ 10000 mm / H2O, a hydrophobic pressure retention of ≥ 5000 mm / H2O after 10 washes at 40°C (washing method ISO6330-4N), and a moisture permeability ≥ 8000 g / m³ (ASTME96BW-1995). 2 • After 24 hours and 10 washes, the moisture permeability is ≥8000g / m². 2 • It has durable and effective waterproof and breathable properties with a breathability of ≥1.0 mm / s (ISO9237) for 24 hours and ≥1.0 mm / s after 10 washes. This effectively avoids the impact on the consumer's wearing experience due to the decline in performance. As a result, the superhydrophobic electrospun film prepared by this method can maintain its original protective properties when applied to clothing fabrics, providing effective protection for the safety of consumers. Detailed Implementation

[0022] The technical solutions described below in conjunction with the embodiments of this application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] The following will describe in detail a method for preparing a superhydrophobic electrospun film according to this application.

[0024] A method for preparing a superhydrophobic electrospun film includes a raw material component and an electrospinning component. The raw material component involves selecting a formulation and preparing a polymer resin, then pulverizing the polymer resin to obtain a modified resin powder. The electrospinning component involves heating and melting the modified resin powder to obtain molten resin, then electrospinning the molten resin under a high-voltage electric field to form a superhydrophobic film layer on the surface of a mold. Finally, the film is cooled with cooling water, unmolded, and packaged to obtain the finished superhydrophobic electrospun film.

[0025] In this embodiment, the electrospinning process employs conventional existing technology, which will not be elaborated upon here. To effectively control and achieve superhydrophobic and breathable properties, the high-voltage electric field in the electrospinning process is set at 1-20kV, the receiving distance is 5-25cm, and the feed rate of the molten resin is controlled at 0.5-3mL / h to effectively form a superhydrophobic film layer with the corresponding functional effects. The fiber diameter obtained by electrospinning is 360-5200nm, and room-temperature circulating water is sufficient for cooling, thus effectively controlling production costs.

[0026] It should be mentioned that the formulation consists of 10-30 parts by weight of PU polyurethane, 5-10 parts of polyamide 6, 3-6 parts of modified nano silica, and 1-2 parts of polyetherimide.

[0027] The modified nano-silica preparation method includes step ① dispersing nano-silica in a 1% hydrochloric acid solution, controlling the temperature of the hydrochloric acid solution at 220-260℃, shaking, and then washing with water to obtain hydroxylated silica; step ② dispersing the hydroxylated silica in isopropanol and / or diethyl ether, then adding dimethylaminoethyl acetate dropwise to the isopropanol and / or diethyl ether, with a molar ratio of dimethylaminoethyl acetate to hydroxylated silica of 2-5:1, and obtaining dimethylaminoethyl ether by stirring with an organic bismuth catalyst. Step 3: Caprolactam is added dropwise to dimethylaminoethyl silica to react and obtain caprolactam polymerized silica. The mass ratio of caprolactam to hydroxylated silica is controlled at 100:4-25, the reaction temperature is 60℃, and the reaction time is 1-2h. Step 4: Caprolactam polymerized silica is mixed with caprolactam for polymerization reaction. The polymerization reaction temperature is controlled at 150-220℃, and the reaction time is 2-3h to obtain polyamide 6 grafted modified nano silica.

[0028] Meanwhile, the powdering process includes grinding using a planetary ball mill, controlling the diameter of the grinding agate balls to be 4-12 mm, and the grinding time to be 0.5-1 h.

[0029] To further improve the stable contact angle of the prepared superhydrophobic electrospun film, an additive of 0.1-1 wt% of the polymer resin can be filled into the planetary ball mill, and the additive is at least one of TiO2, ZnO, Al2O3, and Fe2O3.

[0030] Example 1

[0031] A method for preparing a superhydrophobic electrospun film includes a raw material component and an electrospinning component. The raw material component involves selecting a formulation and preparing a polymer resin, then pulverizing the polymer resin to obtain a modified resin powder. The electrospinning component involves heating and melting the modified resin powder to obtain molten resin, then electrospinning the molten resin under a high-voltage electric field to form a superhydrophobic film layer on the mold surface. Finally, the film is cooled with cooling water, unmolded, and packaged to obtain the finished superhydrophobic electrospun film.

[0032] In this embodiment, the electrospinning process employs conventional existing technology, which will not be elaborated upon here. To effectively control and achieve superhydrophobic and breathable properties, the high-voltage electric field in the electrospinning process is set to 10kV, the receiving distance to 12cm, and the feed rate of the molten resin is controlled at 0.5mL / h to effectively form the superhydrophobic film layer with the corresponding functional effects. The fiber diameter obtained by electrospinning is 450nm, and room-temperature circulating water is sufficient for cooling, thus effectively controlling production costs.

[0033] It should be mentioned that the formulation consists of 10 parts by weight of PU polyurethane, 5 parts of polyamide 6, 3 parts of modified nano silica, and 1 part of polyetherimide.

[0034] The modified nano-silica preparation method includes the following steps: Step ① Dispersing nano-silica in a 1% hydrochloric acid solution, controlling the temperature of the hydrochloric acid solution at 220℃, shaking and washing with water to obtain hydroxylated silica; Step ② Dispersing hydroxylated silica in isopropanol, then adding dimethylaminoethyl acetate dropwise to the isopropanol, with a molar ratio of dimethylaminoethyl acetate to hydroxylated silica of 2:1, and stirring under catalysis of an organic bismuth catalyst to obtain dimethylaminoethyl silica; Step ③ Adding caprolactam dropwise to dimethylaminoethyl silica to react and obtain caprolactam polymerized silica, controlling the mass ratio of added caprolactam to hydroxylated silica at 25:1, the reaction temperature at 60℃, and the reaction time at 2h; Step ④ Mixing caprolactam polymerized silica with caprolactam for polymerization reaction, controlling the polymerization reaction temperature at 220℃, and the reaction time at 2h to obtain polyamide 6 grafted modified nano-silica.

[0035] Meanwhile, the powdering process includes grinding using a planetary ball mill, with the diameter of the grinding agate balls controlled at 4 mm and the grinding time at 1 hour.

[0036] Example 2

[0037] A method for preparing a superhydrophobic electrospun film includes a raw material component and an electrospinning component. The raw material component involves selecting a formulation and preparing a polymer resin, then pulverizing the polymer resin to obtain a modified resin powder. The electrospinning component involves heating and melting the modified resin powder to obtain molten resin, then electrospinning the molten resin under a high-voltage electric field to form a superhydrophobic film layer on the mold surface. Finally, the film is cooled with cooling water, unmolded, and packaged to obtain the finished superhydrophobic electrospun film.

[0038] In this embodiment, the electrospinning process employs conventional existing technology, which will not be elaborated upon here. To effectively control and achieve superhydrophobic and breathable properties, the high-voltage electric field in the electrospinning process is set to 18kV, the receiving distance to 20cm, and the feed rate of the molten resin is controlled at 2mL / h to effectively form the superhydrophobic film layer with the corresponding functional effects. The fiber diameter obtained by electrospinning is 420nm, and room-temperature circulating water is sufficient for cooling, thus effectively controlling production costs.

[0039] It should be mentioned that the formulation consists of 20 parts by weight of PU polyurethane, 7 parts of polyamide 6, 4 parts of modified nano silica, and 1.5 parts of polyetherimide.

[0040] The modified nano-silica preparation method includes the following steps: Step ① Dispersing nano-silica in a 1% hydrochloric acid solution, controlling the temperature of the hydrochloric acid solution at 240℃, and washing with water after shaking to obtain hydroxylated silica; Step ② Dispersing hydroxylated silica in diethyl ether, and then adding dimethylaminoethyl acetate dropwise to the diethyl ether, with a molar ratio of dimethylaminoethyl acetate to hydroxylated silica of 3:1, and obtaining dimethylaminoethyl silica by stirring with an organic bismuth catalyst; Step ③ Adding caprolactam dropwise to dimethylaminoethyl silica to react and obtain caprolactam polymerized silica, controlling the mass ratio of added caprolactam to hydroxylated silica at 10:1, the reaction temperature at 60℃, and the reaction time at 1.5h; Step ④ Mixing caprolactam polymerized silica with caprolactam for polymerization reaction, controlling the polymerization reaction temperature at 200℃, and the reaction time at 2.5h to obtain polyamide 6 grafted modified nano-silica.

[0041] Meanwhile, the powdering process includes grinding using a planetary ball mill, with the diameter of the grinding agate balls controlled at 12 mm and the grinding time at 0.5 h.

[0042] Example 3

[0043] A method for preparing a superhydrophobic electrospun film includes a raw material component and an electrospinning component. The raw material component involves selecting a formulation and preparing a polymer resin, then pulverizing the polymer resin to obtain a modified resin powder. The electrospinning component involves heating and melting the modified resin powder to obtain molten resin, then electrospinning the molten resin under a high-voltage electric field to form a superhydrophobic film layer on the mold surface. Finally, the film is cooled with cooling water, unmolded, and packaged to obtain the finished superhydrophobic electrospun film.

[0044] In this embodiment, the electrospinning process employs conventional existing technology, which will not be elaborated upon here. To effectively control and achieve superhydrophobic and breathable properties, the high-voltage electric field in the electrospinning process is set to 8kV, the receiving distance to 17cm, and the feed rate of the molten resin is controlled at 3mL / h to effectively form the superhydrophobic film layer with the corresponding functional effects. The fiber diameter obtained by electrospinning is 480nm, and room-temperature circulating water is sufficient for cooling, thus effectively controlling production costs.

[0045] It should be mentioned that the formulation consists of 30 parts by weight of PU polyurethane, 10 parts of polyamide 6, 6 parts of modified nano silica, and 2 parts of polyetherimide.

[0046] The modified nano-silica preparation method includes the following steps: Step ① Dispersing nano-silica in a 1% hydrochloric acid solution, controlling the temperature of the hydrochloric acid solution at 260℃, and washing with water after shaking to obtain hydroxylated silica; Step ② Dispersing hydroxylated silica in isopropanol, and then adding dimethylaminoethyl acetate dropwise to the isopropanol, with a molar ratio of dimethylaminoethyl acetate to hydroxylated silica of 5:1, and obtaining dimethylaminoethyl silica by stirring with an organic bismuth catalyst; Step ③ Adding caprolactam dropwise to dimethylaminoethyl silica to react and obtain caprolactam polymerized silica, controlling the mass ratio of added caprolactam to hydroxylated silica to be 4:1, the reaction temperature to be 60℃, and the reaction time to be 1h; Step ④ Mixing caprolactam polymerized silica with caprolactam for polymerization reaction, controlling the polymerization reaction temperature to be 190℃, and the reaction time to be 3h to obtain polyamide 6 grafted modified nano-silica.

[0047] Meanwhile, the powdering process includes grinding using a planetary ball mill, with the diameter of the grinding agate balls controlled at 7 mm and the grinding time at 0.8 h.

[0048] Example 4

[0049] The difference between Example 4 and Example 1 is that a metal oxide catalyst was added to the polymerization reaction in Example 4, and the reaction temperature was 150°C. Furthermore, the metal oxide catalyst used in Example 4 of this application is alumina.

[0050] Example 5

[0051] The difference between Example 5 and Example 1 is that a metal oxide catalyst was added to the polymerization reaction in Example 5, and the reaction temperature was 160°C. Furthermore, the metal oxide catalyst used in Example 4 of this application is alumina.

[0052] Example 6

[0053] The difference between Example 6 and Example 2 is that the planetary ball mill in Example 6 is filled with an additive of 0.1 wt% of the polymer resin, and the additive is ZnO.

[0054] Example 7

[0055] The difference between Example 7 and Example 2 is that the planetary ball mill in Example 7 is filled with an additive accounting for 1 wt% of the polymer resin mass, and the additive is TiO2 and Fe2O3 with a molar ratio of 1.

[0056] Comparative Example 1

[0057] The difference between Comparative Example 1 and Example 2 is that in Comparative Example 1, silica was added instead of modified nano-silica.

[0058] Comparative Example 2

[0059] The difference between Comparative Example 2 and Example 2 is that step ① was not performed in the modified nano-silica in Comparative Example 2.

[0060] Comparative Example 3

[0061] The difference between Comparative Example 3 and Example 2 is that step ④ was not performed in the modified nano-silica in Comparative Example 3.

[0062] Performance tests were performed on Examples 1 to 4, Example 6, and Comparative Examples 1 to 3.

[0063] 1. Initial water pressure was tested using ISO 811;

[0064] 2. The material to be tested was washed at room temperature (40℃) using ISO6330-4N, and the hydrostatic pressure was maintained at ≥5000 mm / H2O after 10 washes.

[0065] 3. The moisture permeability was tested using ASTM E96BW-1995;

[0066] 4. Air permeability is tested using ISO9237.

[0067] The test results are shown in Table 1 below:

[0068] Table 1. Test Results of Hydrophobic and Air-Permeability Properties

[0069]

[0070]

[0071] As shown in Table 1 above, in this embodiment, the addition of modified nano-silica avoids affecting the moisture permeability and air permeability of the superhydrophobic electrospun membrane while achieving the purpose of binding with polyamide 6 to achieve superhydrophobicity. Comparing Example 2 and Example 6, it can be seen that filling the planetary ball mill with a metal oxide such as zinc oxide at a mass ratio of 0.1 wt% of the polymer resin as an additive enhances the formation of the polymer's contact angle structure, thereby forming a textured surface on the polymer to further improve superhydrophobic performance. Meanwhile, based on Example 2 and Comparative Examples 1 to 3 of this application, it can be seen that the preparation of modified nano-silica in this embodiment achieves the conversion of silica from hydrophilic to hydrophobic, and synergistically achieves strength, pressure resistance, and effective moisture and air permeability when mixed with PU polyurethane and polyamide 6, while maintaining a durable and effective high contact angle. Even after multiple washes, a large contact angle is retained, improving user comfort while ensuring its hydrophobic ability.

[0072] In summary, this application provides a method for preparing a superhydrophobic electrospun membrane. The superhydrophobic electrospun membrane prepared by this method using electrospinning and corresponding components exhibits an initial water pressure (ISO811, 60 cm / min) ≥ 10000 mm / H2O, a hydrophobic pressure retention of ≥ 5000 mm / H2O after 10 washes at 40°C (washing method ISO6330-4N), and a moisture permeability ≥ 8000 g / m³ (ASTME96BW-1995). 2 • After 24 hours and 10 washes, the moisture permeability is ≥8000g / m². 2 • It has durable and effective waterproof and breathable properties with a breathability of ≥1.0 mm / s (ISO9237) for 24 hours and ≥1.0 mm / s after 10 washes. This effectively avoids the impact on the consumer's wearing experience due to the decline in performance. As a result, the superhydrophobic electrospun film prepared by this method can maintain its original protective properties when applied to clothing fabrics, providing effective protection for the safety of consumers.

[0073] The terms “first,” “second,” “third,” “fourth,” etc., used in this application (if applicable) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, or apparatus.

[0074] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0075] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method of preparing a superhydrophobic electrospun membrane, the method comprising: The raw material component part and the electrostatic spinning part are included. ​ The raw material component part is obtained by selecting a formula composition and preparing a polymer resin, powderizing the polymer resin to obtain a modified resin powder, grinding the modified resin powder by using a planetary ball mill, and controlling the diameter of the grinding agate ball to be 4-12 mm and the grinding time to be 0.5-1 h; the planetary ball mill is filled with an additive in a mass ratio of 0.1-1 wt% of the polymer resin, and the additive is at least one of TiO2, ZnO, Al2O3, and Fe2O3. The electrostatic spinning part is obtained by heating and melting the modified resin powder to obtain a molten resin, electrospinning the molten resin by a high-voltage electric field to form a super-hydrophobic film layer on the surface of a mold, and cooling the film layer by using cooling water to obtain a finished product of the super-hydrophobic electrostatic spinning film. The formula composition includes 10-30 parts of PU polyurethane, 5-10 parts of polyamide 6, 3-6 parts of modified nano-silicon dioxide, and 1-2 parts of polyetherimide by weight. In step ②, the dimethylaminoethyl acetate is added dropwise, and the molar ratio of the dimethylaminoethyl acetate to the hydroxylated silicon dioxide is 2-5:

1.

2. The method of claim 1, wherein: In step ②, the catalyst is an organic bismuth catalyst, and the organic bismuth catalyst is preferably one or a mixture of more than one of bismuth neodecanoate, bismuth stearate, bismuth myristate, and bismuth eicosanoate.

3. The method of claim 1, wherein: In step ③, the caprolactam is added dropwise, and the mass ratio of the caprolactam to the hydroxylated silicon dioxide is 100:4-25.

4. The method of claim 1, wherein: In step ③, the reaction temperature is 50-80℃, and the reaction time is 1-5 h.

5. The method of claim 1, wherein: In step ④, the polymerization reaction temperature is 150-220℃, and the reaction time is 2-3 h.

6. The method of claim 1, wherein: A metal oxide catalyst is added in the polymerization reaction, and the reaction temperature is 150-160℃.

7. The method of claim 6, wherein the method further comprises: The voltage of the high-voltage electric field is 3-100 kV, the receiving distance is 5-40 cm, and the feeding flow rate of the molten resin is 0.2-4 mL / h.

8. The method of claim 1, wherein: ​

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