Preparation method of windproof, waterproof and moisture-permeable film

Abstract

The present application relates to the technical field of windproof, waterproof and moisture-permeable film, and particularly relates to a preparation method of windproof, waterproof and moisture-permeable film, which comprises the following steps: dissolving polyether block polyamide in hexafluoroisopropanol to obtain a spinning solution, and obtaining the windproof, waterproof and moisture-permeable film through electrospinning and drying, wherein the polyether block polyamide is a block copolymer composed of nylon 12 and polytetrahydrofuran ether diol, and the mass percentage of nylon 12 is 50%; the polyether block polyamide is dissolved in hexafluoroisopropanol, and a nanometer microporous fiber film is prepared by using an electrospinning method. The windproof, waterproof and moisture-permeable effect is achieved by relying on the three-dimensional stacking of the micro-nano pore structure and the hydrophilicity of the material itself. Although the material has a large number of pore structures, there is no obvious vertical hole after 3D staggered stacking, and the material has good windproof effect. The good hydrophilicity and pore structure of the material itself make the water vapor quickly transfer between the material and the pores to achieve the moisture-permeable function, and the micro-nano level holes on the surface are much smaller than the diameter of the water droplets, so that the waterproof effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of windproof, waterproof, and breathable membrane technology, and in particular to a method for preparing a windproof, waterproof, and breathable membrane. Background Technology

[0002] Windproof, waterproof, and breathable membranes are increasingly used in outdoor clothing, medical protective equipment, and industrial production. Currently, there are two main technical solutions on the market. One involves using traditional waterproof materials such as polytetrafluoroethylene (PTFE) to prepare nanoporous membranes, relying on the microporous structure to regulate breathability and moisture permeability. This method is complex and poses safety risks to human health due to fluorine. The second method uses hydrophilic materials such as polyurethane to create nanoporous membranes, relying on modification or post-treatment to achieve waterproofing. This method is complex to operate and has poor durability. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of the present invention provide a method for preparing a windproof, waterproof, and breathable membrane.

[0004] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: On one hand, the present invention provides a method for preparing a windproof, waterproof, and breathable membrane, comprising the following steps: Polyether block polyamide is dissolved in hexafluoroisopropanol to obtain a spinning solution. A windproof, waterproof and breathable membrane is obtained by electrospinning and drying. The polyether block polyamide is a block copolymer composed of hard segment nylon 12 and soft segment polytetrahydrofuran ether diol. The mass percentage of nylon 12 is 50%.

[0005] In some embodiments, the concentration of the spinning solution is 3 to 3.5 wt%.

[0006] In some embodiments, the melting temperature is controlled at 15~40°C.

[0007] In some embodiments, the electrospinning flow rate is 0.01~3mL / h, the voltage is 10~30kV, and the receiving distance is 10~25cm.

[0008] In some embodiments, the temperature of the electrospinning is controlled at 23~27°C and the humidity is controlled at 40~60%.

[0009] In some embodiments, the drying temperature is 60~80°C and the time is 1 hour.

[0010] In some embodiments, the number-average molecular weight of the polytetramethylene ether glycol is 400 to 3000.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: Nanoporous fiber membranes were prepared by electrospinning polyether block polyamide (PEBA) dissolved in hexafluoroisopropanol. The membranes achieve windproof, waterproof, and breathable properties through the three-dimensional stacking of the micro- and nano-porous structures and the material's inherent hydrophilicity. Despite possessing numerous pores, the 3D staggered stacking results in the absence of obvious vertical pores, providing excellent windproof performance. The material's good hydrophilicity and pore structure allow for rapid water vapor transfer between the material and the pores, achieving breathability. The micro- and nano-sized pores on the surface are much smaller than the diameter of water droplets, achieving a waterproof effect.

[0012] In summary, the single-solute electrospinning technology ensures excellent spinning solution uniformity, avoiding the inhomogeneities that often occur when spinning multiple materials in combination. The solvent has a boiling point of only 59℃, leaves no residue after drying, and the PEBA material itself is fluorine-free, posing no harm to the human body. The hydrophilicity and micro / nano structure of PEBA achieve windproof, waterproof, and breathable functionality with excellent durability. The operation is simple, requiring only electrospinning followed by drying to obtain the finished product, making it suitable for large-scale mass production. Attached Figure Description

[0013] Figure 1 Here is a scanning electron microscope image of Example 1; Figure 2 Here is a scanning electron microscope image of Example 2; Figure 3 This is a scanning electron microscope image of Comparative Example 1; Figure 4 This is a scanning electron microscope image of Comparative Example 3; Figure 5 This is a scanning electron microscope image of Comparative Example 4; Figure 6 For contact angle photographs, (1) Example 1; (2) Example 2; (3) Comparative Example 1; (4) Comparative Example 2. Detailed Implementation

[0014] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0015] Currently, the market offers solutions for preparing nanoporous membranes using traditional waterproofing materials such as polytetrafluoroethylene (PTFE), relying on the microporous structure to regulate breathability and moisture permeability. However, this method is complex and poses safety risks to human health due to the presence of fluorine. Furthermore, using hydrophilic materials like polyurethane to create nanoporous membranes, relying on modification or post-treatment to achieve waterproofing, is also complex and has poor durability.

[0016] This invention provides a method for preparing a windproof, waterproof, and breathable membrane, comprising the following steps: Polyether block polyamide was dissolved in hexafluoroisopropanol to obtain a spinning solution. A windproof, waterproof, and breathable membrane was obtained through electrospinning and drying. The polyether block polyamide is a block copolymer composed of nylon 12 and polytetrahydrofuran ether diol, with nylon 12 comprising 50% by mass. It should be noted that the soft segment of the polyether block polyamide is PTMG (Mn=2000), and the hard segment is PA12, with a content of 50%. It is an industrial grade product from Wanhua Chemical Group Co., Ltd., model: WHE-4011. Therefore, polyether block polyamide with a content of 50% will be referred to as PEBA-50, and polyether block polyamide with a content of 20% will be referred to as PEBA-20. Hexafluoroisopropanol: Shanghai Haohong Biomedical Technology Co., Ltd., CSA: 920-66-1.

[0017] In some embodiments, the concentration of the spinning solution is 3 to 3.5 wt%. For example, it can be 3 wt%, 3.1 wt%, 3.2 wt%, 3.4 wt%, or 3.5 wt%. This embodiment of the application does not specifically limit the concentration of the spinning solution.

[0018] In some embodiments, the melting temperature is controlled at 15~40°C. Exemplarily, it can be 15°C, 20°C, 25°C, 30°C, 35°C, or 40°C. This application embodiment does not specifically limit this.

[0019] In some embodiments, the electrospinning flow rate is 0.01~3 mL / h. Exemplarily, it can be 0.01 mL / h, 0.1 mL / h, 0.5 mL / h, 1 mL / h, 1.2 mL / h, 1.5 mL / h, 1.8 mL / h, 2 mL / h, 2.1 mL / h, 2.3 mL / h, 2.5 mL / h, 2.6 mL / h, 2.8 mL / h, 2.9 mL / h, or 3 mL / h. This embodiment does not specifically limit the flow rate. The voltage is 10~30 kV. Exemplarily, it can be... The voltage ratings are 10kV, 12kV, 13kV, 15kV, 16kV, 18kV, 20kV, 21kV, 23kV, 25kV, 26kV, 28kV, and 30kV. This application does not specifically limit the voltage ratings in the embodiments. The receiving distance is 10~25cm, and for example, it can be 10cm, 12cm, 13cm, 15cm, 16cm, 17cm, 18cm, 20cm, 21cm, 22cm, 23cm, and 25cm. The receiving substrate is one of release paper, tin foil, or glossy paper.

[0020] In some embodiments, the temperature of electrospinning is controlled at 23~27°C. For example, it can be 23°C, 24°C, 25°C, 26°C, or 27°C. This embodiment of the application does not specifically limit the temperature. The humidity is controlled at 40~60%. For example, it can be 40%, 41%, 42%, 43%, 45%, 46%, 48%, 50%, 51%, 52%, 53%, 54%, 56%, 58%, or 60%. This embodiment of the application does not specifically limit the humidity.

[0021] In some embodiments, the drying temperature is 60~80℃, and exemplaryly, it can be 60℃, 62℃, 63℃, 64℃, 65℃, 68℃, 70℃, 72℃, 74℃, 75℃, 76℃, 78℃, or 80℃. This embodiment of the application does not specifically limit this temperature; the drying time is 1 hour.

[0022] In some embodiments, the number-average molecular weight of the polytetramethylene ether glycol is 400 to 3000.

[0023] Example 1

[0024] A mixture of PEBA-50 (0.6 g) and hexafluoroisopropanol (19.4 g, purity 97%) was weighed and stirred at 40 °C for 2.0 h to obtain a spinning solution. The obtained spinning solution was electrospun at 25 °C and 50% humidity for 2 h (flow rate 0.8 mL / h, receiving distance 18 cm, voltage 17 kV), and dried at 80 °C for 1 h to obtain a nanofiber membrane.

[0025] Example 2

[0026] A mixture of PEBA-50 (0.7 g) and hexafluoroisopropanol (19.3 g, 97% purity) was weighed and stirred at 40 °C for 2.0 h to obtain a spinning solution. The obtained spinning solution was electrospun at 25 °C and 50% humidity for 2 h (flow rate 0.8 mL / h, receiving distance 18 cm, voltage 17 kV), and dried at 80 °C for 1 h to obtain a nanofiber membrane.

[0027] Comparative Example 1 A mixture of PEBA-50 (0.5 g) and hexafluoroisopropanol (19.5 g, 97% purity) was weighed and stirred at 40 °C for 2.0 h to obtain a spinning solution. The obtained spinning solution was electrospun at 25 °C and 50% humidity for 2 h (flow rate 0.8 mL / h, receiving distance 18 cm, voltage 17 kV), and dried at 80 °C for 1 h to obtain a nanofiber membrane.

[0028] Comparative Example 2 PEBA-50 was hot-pressed into a non-porous membrane using a flat vulcanizing machine, and its hydrophilicity was measured as a control.

[0029] Comparative Example 3 A mixture of PEBA-20 (0.6 g) and hexafluoroisopropanol (19.4 g, 97% purity) was weighed and stirred at 40 °C for 2.0 h to obtain a spinning solution. The resulting spinning solution was electrospun at 25 °C and 50% humidity for 2 h (flow rate 0.8 mL / h, receiving distance 18 cm, voltage 17 kV), and dried at 80 °C for 1 h to obtain a nanofiber membrane.

[0030] Comparative Example 4 A mixture of PEBA-50 (0.6 g) and n-butanol (19.4 g, analytical grade) was weighed and stirred at 40 °C for 2.0 h to obtain a spinning solution. The obtained spinning solution was electrospun at 25 °C and 50% humidity for 2 h (flow rate 0.8 mL / h, receiving distance 18 cm, voltage 17 kV), and dried at 80 °C for 1 h to obtain a nanofiber membrane.

[0031] Performance testing: Air permeability: Tested according to GB / T 5453-1997 "Textiles - Determination of Air Permeability of Fabrics", area 50cm² 2 Pressure drop of 100 Pa.

[0032] Moisture permeability: determined according to GB / T 12704.1-2009 "Textiles - Test methods for moisture permeability of fabrics - Part 1: Moisture absorption method".

[0033] Contact angle: sitting drop method.

[0034] It can be seen that the nanofiber membranes prepared in Examples 1 and 2 both possess well-formed cylindrical nanofibers with uniform micro- and nano-pores between the fibers. These micro- and nano-pores can prevent larger water droplets (>20 μm) from passing through, achieving a waterproof effect. The contact angles are 113° and 108°, respectively, and their water repellency is significantly better than that of the non-porous membrane in Comparative Example 2. Water vapor diameter is often <0.1 nm, and it can be conducted through these pores, thus exhibiting good moisture permeability. As shown in Table 1 below, the moisture permeability is 7952 g / m³. 2 ·24h and 8400 g / m 2 • 24h. By controlling the thickness of fiber stacking, the pathways of the gaps can be adjusted. When there are enough fiber layers, these gaps are no longer vertical pathways, which can achieve the function of windproofing. The air permeability is 3.84 mm / s and 3.78 mm / s, respectively.

[0035] Figure 3The image shown is a scanning electron microscope image of Comparative Example 1. It reveals not only nanofibers but also beaded and fiber-interconnected structures. These adhesions and beading reduce membrane porosity and increase inter-fiber connectivity, resulting in a larger contact area for water droplets. Due to the inherent hydrophilic properties of polyethers and polyamides, this structure actually enhances hydrophilicity, with a contact angle of only 62°, lower than the 72° of the non-porous membrane in Comparative Example 2. Simultaneously, the inter-fiber adhesion effectively facilitates water molecule transmission. Although porosity is reduced, the combined effect of pore size and inter-fiber conduction significantly improves permeability, achieving a permeability of 10458 g / m³. 2 ·24h.

[0036] Figure 4 , Figure 5 These are scanning electron microscope images of Comparative Examples 3-4. Compared to Example 1, Comparative Example 3 shows that the only difference is the hard segment content of the PEBA raw material, which is 20%. When the hard segment content is low, the fiber morphology is irregular, with a large number of beads present. Comparative Example 4 uses n-butanol as a solvent. Compared to Example 1, it did not form a normal fiber structure, indicating that hexafluoroisopropanol is more suitable as a solvent for PEBA materials.

[0037] Table 1 Sample Performance

[0038] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a windproof, waterproof, and breathable membrane, characterized in that, Includes the following steps: A polyether block polyamide is dissolved in hexafluoroisopropanol to obtain a spinning solution. A windproof, waterproof and breathable membrane is obtained by electrospinning and drying. The polyether block polyamide is a block copolymer composed of nylon 12 and polytetrahydrofuran ether diol, wherein the mass percentage of nylon 12 is 50%.

2. The preparation method according to claim 1, characterized in that, The concentration of the spinning solution is 3~3.5wt%.

3. The preparation method according to claim 1, characterized in that, The melting temperature is controlled between 15 and 40°C.

4. The preparation method according to claim 1, characterized in that, The electrospinning flow rate is 0.01~3mL / h, the voltage is 10~30kV, and the receiving distance is 10~25cm.

5. The preparation method according to claim 1, characterized in that, The temperature of the electrospinning is controlled at 23~27℃ and the humidity is controlled at 40~60%.

6. The preparation method according to claim 1, characterized in that, The drying temperature is 60~80℃, and the time is 1 hour.

7. The preparation method according to claim 1, characterized in that, The number-average molecular weight of the polytetramethylene ether diol is 400-3000.

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