A transparent waterproof and moisture-permeable film and its preparation method and application

Abstract

The present invention discloses a transparent waterproof and breathable membrane, a preparation method, and an application thereof. The method comprises the following steps: S1, spinning a polyamide spinning solution using an electrospinning method to obtain an intermediate; S2, mixing the intermediate with a fluorine-free hydrophobic agent solution, impregnating the mixture, and drying the mixture; wherein the polyamide spinning solution includes a crosslinking agent. The present invention selects polyamide as the spinning polymer, uses a crosslinking agent in combination with an electrospinning technique to obtain an intermediate, and then mixes the intermediate with a fluorine-free hydrophobic agent solution, impregnating the mixture, and drying the resulting waterproof and breathable membrane. By adjusting the drying temperature, the membrane not only has waterproof and breathable properties but also has high transparency and low haze.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer films, in particular to a transparent waterproof and moisture-permeable film and a preparation method and application thereof. Background Art

[0002] With the improvement of living standards and economic conditions, people are increasingly demanding more comfortable and functional clothing. However, traditional textiles cannot effectively protect against rain and provide a comfortable environment for the wearer. Waterproof and breathable membranes, which effectively prevent liquid water penetration while allowing water vapor transmission, are attracting attention for their ability to provide an ideal microclimate and comfort due to their strong waterproofness and high breathability.

[0003] In recent years, due to the convenience of electrospinning technology, the wide source of raw materials, and the advantages of electrospun nanofibers such as small diameter, high porosity, and large specific surface area, the conventional methods for preparing waterproof and breathable membranes often have the following defects: it is difficult to balance the waterproof and breathable properties, and it is impossible to have the characteristics of high transparency and low haze at the same time.

[0004] Therefore, it is necessary to provide a new method for preparing a waterproof and breathable membrane. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, in a first aspect, the present invention provides a method for preparing a transparent waterproof and breathable film. The transparent waterproof and breathable film prepared by the method is not only waterproof and breathable, but also has high transparency and low haze.

[0006] The second aspect of the present invention further provides a transparent waterproof and moisture-permeable film.

[0007] The third aspect of the present invention further provides an application of a transparent waterproof and moisture-permeable film.

[0008] According to a first aspect of the present invention, a method for preparing a transparent waterproof and moisture-permeable film is provided, comprising the following steps:

[0009] S1, spinning the electrospinning solution by an electrospinning method to obtain an intermediate;

[0010] S2, mixing the intermediate and the fluorine-free hydrophobic agent solution, impregnating the mixture, and drying the mixture;

[0011] The electrospinning solution comprises a polyamide solution and a crosslinker solution; the polyamide in the polyamide solution is selected from alcohol-soluble PA6;

[0012] The crosslinking agent in the crosslinking agent solution is selected from a polyol crosslinking agent, an epoxy crosslinking agent, a polyacrylamide crosslinking agent or an organosilicon crosslinking agent.

[0013] The method for preparing a transparent waterproof and breathable film according to an embodiment of the present invention has at least the following beneficial effects:

[0014] The present invention selects alcohol-soluble PA6 polyamide as the spinning polymer, and uses electrostatic spinning technology to obtain an intermediate in combination with a cross-linking agent. The intermediate and a fluorine-free hydrophobic agent solution are mixed, impregnated, and dried to obtain a waterproof and breathable membrane, which not only has waterproof and breathable effects, but also has high transparency and low haze.

[0015] Furthermore, the introduction of a crosslinking agent into the polyamide fiber improves the hydrophobic durability of the fiber membrane.

[0016] It can be understood that the alcohol-soluble PA6 of the present invention refers to PA6 using ethanol as a solvent.

[0017] According to some embodiments of the present invention, the concentration of the polyamide solution is 12 wt % to 16 wt %.

[0018] According to some embodiments of the present invention, the concentration of the fluorine-free hydrophobic agent solution is 1 wt % to 5 wt %.

[0019] According to some embodiments of the present invention, the drying temperature is 120-240° C. Thus, when the temperature is set within the above range, the crystallinity can be increased, the haze can be gradually reduced, and the transparency can be improved.

[0020] According to some embodiments of the present invention, the hydrophobic agent of the fluorine-free hydrophobic agent solution is selected from at least one of silicone hydrophobic agents, paraffin hydrophobic agents, methyl acrylate, polyester hydrophobic agents and polymethyl methacrylate.

[0021] According to some embodiments of the present invention, in step S1, the electrospinning parameters include:

[0022] Voltage 25kV~30kV, receiving distance 15cm~20cm, perfusion speed 2~5mL / h, temperature 25℃~27℃, relative humidity 40%~45%.

[0023] According to some embodiments of the present invention, the immersion time is 15 min to 30 min.

[0024] According to an embodiment of the second aspect of the present invention, a transparent waterproof and moisture-permeable membrane is provided, which is prepared by the preparation method described in the first aspect of the present invention.

[0025] Therefore, the transparent waterproof and moisture-permeable film provided by the present invention not only has the effect of being waterproof and moisture-permeable, but also has high transparency and low haze.

[0026] According to some embodiments of the present invention, the waterproof and moisture permeable membrane has a thickness of 60 μm to 100 μm.

[0027] According to some embodiments of the present invention, the average pore size of the waterproof and moisture permeable membrane is 0.3 μm to 1.0 μm.

[0028] A third aspect of the present invention provides an application of the waterproof and moisture-permeable membrane in optical display devices, decorations, medical devices, electronic screens or smart wearable devices.

[0029] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0030] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0031] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0032] Some of the raw materials of the present invention are as follows:

[0033] Alcohol-soluble polyamide: alcohol-soluble PA6; purchased from Shanghai Zhenwei Composite Co., Ltd. ES-42;

[0034] Solvent-based polyamide: polyamide 6; Jiangmen Tongfeng Chemical Glass Equipment Co., Ltd.;

[0035] Polyol crosslinker: Bayhydur 3100; Beijing Kemite Technology Development Co., Ltd.;

[0036] Epoxy crosslinking agent: XR-500; purchased from Shanghai Xirun Chemical Technology Co., Ltd.;

[0037] Polyacrylamide crosslinker: SAC-100; Shanghai Youen Chemical Co., Ltd.

[0038] Silicone crosslinking agent: XR-100; purchased from Shanghai Xirun Chemical Technology Co., Ltd.

[0039] Fluorine-free hydrophobic agent: paraffin-based fluorine-free hydrophobic agent; purchased from Shanghai Zuohang New Material Technology Co., Ltd.; silicone-based fluorine-free hydrophobic agent; purchased from Beijing Qifei Technology Development Co., Ltd.

[0040] Example 1

[0041] This example provides a transparent waterproof and breathable membrane with a thickness of 60 μm and a pore size of 0.8 μm. The preparation method thereof comprises the following steps:

[0042] Polyamide spinning solution: 14 wt% alcohol-soluble PA6 and 2 wt% epoxy crosslinking agent were dissolved in anhydrous ethanol to prepare an electrospinning solution.

[0043] Fluorine-free hydrophobic agent solution: dissolve the paraffin-based fluorine-free hydrophobic agent in deionized water and dilute it to a paraffin-based fluorine-free hydrophobic agent solution with a mass fraction of 1%.

[0044] S1. Using glossy paper as a receiving substrate, place the prepared electrospinning solution on an electrospinning pump; set the electrospinning parameters as follows: voltage 25 kV, receiving distance 15 cm, perfusion rate 3 mL / h, temperature 25°C, relative humidity 40%, and then perform spinning to obtain an intermediate;

[0045] S2. The prepared intermediate was removed and placed in a 1 wt% paraffin-based fluorine-free hydrophobic agent for immersion for 20 minutes, and then taken out and dried in a drying oven at a temperature of 120° C. for 10 minutes to obtain a transparent waterproof and moisture-permeable film.

[0046] Example 2

[0047] This example provides a transparent waterproof and breathable membrane with a thickness of 70 μm and a pore size of 1 μm. The preparation method is as follows:

[0048] Spinning solution: 14 wt% alcohol-soluble PA6 and 2 wt% organosilicon cross-linking agent were dissolved in anhydrous ethanol to prepare an electrospinning solution.

[0049] Fluorine-free hydrophobic agent: dissolve the organosilicon-based fluorine-free hydrophobic agent in deionized water to dilute it into an organosilicon-based fluorine-free hydrophobic agent solution with a mass fraction of 3 wt%.

[0050] S1. Using glossy paper as a receiving substrate, place the prepared electrospinning solution on an electrospinning pump; set the electrospinning parameters as follows: voltage 28 kV, receiving distance 18 cm, perfusion rate 3 mL / h, temperature 27°C, relative humidity 45%, and then perform spinning to obtain an intermediate;

[0051] S2. The prepared intermediate was removed and placed in a 3 wt % organosilicon-based fluorine-free hydrophobic agent for immersion for 20 minutes, and then taken out and dried in a drying oven at a temperature of 120° C. for 10 minutes to obtain a transparent waterproof and moisture-permeable film.

[0052] Example 3

[0053] This example provides a transparent waterproof and breathable membrane with a thickness of 92 μm and a pore size of 1 μm. The preparation method is as follows:

[0054] Spinning solution: 14 wt% alcohol-soluble PA6 and 2 wt% polyol cross-linking agent were dissolved in anhydrous ethanol to prepare an electrospinning solution.

[0055] Fluorine-free hydrophobic agent: dissolve the paraffin-based fluorine-free hydrophobic agent in deionized water to dilute it into a paraffin-based fluorine-free hydrophobic agent solution with a mass fraction of 5 wt%.

[0056] S1. Using glossy paper as a receiving substrate, place the prepared electrospinning solution on an electrospinning pump; set the electrospinning parameters as follows: voltage 25 kV, receiving distance 19 cm, perfusion rate 3 mL / h, temperature 26°C, relative humidity 43%, and then perform spinning to obtain an intermediate;

[0057] S2. The prepared intermediate was removed and placed in a 5 wt % paraffin-based fluorine-free hydrophobic agent for immersion for 20 minutes, and then taken out and dried in a drying oven at a temperature of 150° C. for 10 minutes to obtain a transparent waterproof and moisture-permeable film.

[0058] Example 4

[0059] This example provides a waterproof and breathable membrane, the preparation method and dosage of which are basically the same as those in Example 1, except that the drying temperature is 100°C.

[0060] Comparative Example 1

[0061] Comparative Example 1 provides a waterproof and breathable membrane, and its preparation method is as follows:

[0062] Spinning solution: 14 wt% alcohol-soluble PA6, 2 wt% organosilicon cross-linking agent and 5 wt% polyester-type fluorine-free hydrophobic agent were dissolved in anhydrous ethanol to prepare an electrospinning solution.

[0063] S1. Using glossy paper as the receiving substrate, place the prepared electrospinning solution on an electrospinning pump; set the electrospinning parameters as follows: voltage 27 kV, receiving distance 20 cm, perfusion rate 3 mL / h, temperature 26°C, relative humidity 43%, and then perform spinning;

[0064] S2: The prepared nanofiber membrane was removed and dried in a drying oven at 150° C. for 10 minutes to obtain a waterproof and moisture-permeable membrane.

[0065] Comparative Example 2

[0066] Comparative Example 2: A waterproof and breathable membrane was prepared, and the preparation method thereof was as follows:

[0067] Spinning solution: 14 wt% alcohol-soluble PA6 was dissolved in anhydrous ethanol to prepare an electrospinning solution.

[0068] Fluorine-free hydrophobic agent: dissolve the paraffin-based fluorine-free hydrophobic agent in deionized water to dilute it into a paraffin-based fluorine-free hydrophobic agent solution with a mass fraction of 5 wt%.

[0069] S1: Using glossy paper as the receiving substrate, place the prepared electrospinning solution on the electrospinning pump; set the electrospinning parameters as follows: voltage 25kV, receiving distance 19cm, perfusion rate 3mL / h, temperature 26°C, relative humidity 43%, and then start spinning;

[0070] S2. The prepared nanofiber membrane was removed and placed in a 5 wt% paraffin-based fluorine-free hydrophobic agent for immersion for 20 minutes, and then taken out and dried in a drying oven at a temperature of 150° C. for 10 minutes to obtain a waterproof and moisture-permeable membrane.

[0071] Comparative Example 3

[0072] Comparative Example 3 prepared a waterproof and breathable membrane. Its preparation method and dosage were basically the same as those in Example 1, except that solvent-based PA6 was used instead of alcohol-soluble PA6.

[0073] Performance Testing

[0074] The waterproof and moisture-permeable membranes prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to the following tests, and the data are shown in Table 1.

[0075] Water resistance: Hydrostatic pressure, the primary indicator of waterproof performance, measures the resistance water encounters through a fabric using the hydrostatic pressure it withstands. This test follows the national standard GB / T4744-1997. The specific steps are as follows: Cut three 18×18 cm squares of fiber membrane from the sample, place them on the disc of the hydrostatic pressure tester, cover them with a black fabric, and tighten the ring to compress the membrane. Set the test parameters to 6000 Pa / min and start the test. Stop the test when the third drop of water appears on the black fabric. Record the value, then replace the fiber membrane and retest. After the test is complete, take the average of the three test results to determine the hydrostatic pressure resistance of the fiber membrane.

[0076] Moisture permeability flux: First, pour about 30mL of deionized water into the moisture permeability cup, cut the sample fiber membrane into a fiber membrane of the same size as the moisture permeability cup, place the fiber membrane on the moisture permeability cup (hydrophobic layer facing down), put on the rubber ring and gasket and fix it with a nut. After fixing, set the instrument parameters: humidity is 50%, constant temperature is 38℃, and air flow speed is 0.44m / s. When the humidity and temperature in the constant temperature box meet the requirements, put in the moisture permeability cup, balance in the constant temperature box for 1 hour, quickly weigh the weight of the moisture permeability cup, record it as m1, then immediately put it into the test instrument for 1 hour, weigh the weight of the moisture permeability cup again, record it as m2. Finally, according to the moisture permeability flux formula Calculate the moisture permeability of each fiber membrane. (WVT in the formula represents the moisture permeability per square meter per day, kg / m 2 ·d;S(m 2) represents the area of ​​the fiber membrane during the test (0.00283m 2 ), Δm(g) represents the mass difference of the same fiber membrane, and t(h) represents the testing time of the fiber membrane.

[0077] Contact angle: The contact angle is the angle between a liquid and a solid surface at first contact. The size of the contact angle reflects the hydrophilicity and hydrophobicity of the fiber membrane. The basic steps for contact angle testing are as follows: Cut the prepared sample into five pieces of fiber membrane slightly smaller than the coverslip and test them five times. Set the contact angle tester to use the sessile drop method and select the Young-Laplace equation for testing. Measure the data from the five times and calculate the average value, which will be used as the contact angle data for the fiber membrane sample.

[0078] Elongation: This test is carried out using the reference standard ISO 2062.

[0079] Transmittance: Use UV-3600Plus to test the transmittance of the fiber membrane. After connecting the machine, set the transmittance test method, adjust the zero and set the baseline, and set the wavelength to 800nm~400nm. When testing the full transmittance, place the sample directly opposite the whiteboard. When testing the diffuse transmittance, remove the whiteboard and place the sample in it for testing.

[0080] Haze: The test method is the ratio of diffuse transmittance to total transmittance.

[0081] Table 1 Examples 1 to 4 and Comparative Examples 1 to 3

[0082]

[0083] As shown in Table 1, the waterproof and breathable fiber membranes provided in Examples 1-3 of the present invention exhibit high water resistance, high moisture permeability, high elongation, and good elasticity. Furthermore, the waterproof and breathable membranes of the present invention exhibit strong bonding and durability. After 30 washes, the water resistance, moisture permeability, contact angle, and elongation of the membranes decreased only slightly compared to the initial wash. Furthermore, the membranes exhibited high transparency and low haze.

[0084] From Comparative Examples 1 to 3, the prepared waterproof and breathable fiber membranes have poor water permeability and elongation, especially Comparative Examples 1 and 3, which have low transparency and high haze and are unqualified.

[0085] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A method for preparing a transparent waterproof and breathable film, characterized in that: The steps include: S1, spinning the electrospinning solution by an electrospinning method to obtain an intermediate; S2, mixing the intermediate and the fluorine-free hydrophobic agent solution, impregnating the mixture, and drying the mixture; The electrospinning solution comprises a polyamide solution and a crosslinking agent solution; the polyamide in the polyamide solution is selected from alcohol-soluble PA6; the drying temperature is 120-240°C; The concentration of the polyamide solution is 12wt% to 16wt%; Wherein, the crosslinking agent in the crosslinking agent solution is selected from one of a polyol crosslinking agent, an epoxy crosslinking agent or an organosilicon crosslinking agent; In step S1, the electrospinning parameters include: Voltage 25kV~30kV, receiving distance 15cm~20cm, perfusion speed 2~5mL / h, temperature 25℃~27℃, relative humidity 40%~45%.

2. The method for preparing a transparent waterproof and breathable membrane according to claim 1, wherein: The concentration of the fluorine-free hydrophobic agent solution is 1 wt% to 5 wt%.

3. The method for preparing a transparent waterproof and breathable membrane according to claim 1, wherein: The hydrophobic agent of the fluorine-free hydrophobic agent solution is selected from at least one of silicone hydrophobic agents, paraffin hydrophobic agents, methyl acrylate, polyester hydrophobic agents and polymethyl methacrylate.

4. The method for preparing a transparent waterproof and breathable membrane according to claim 1, wherein: The immersion time is 15 minutes to 30 minutes.

5. A transparent waterproof and breathable film, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 4.

6. The transparent waterproof and breathable membrane according to claim 5, characterized in that The transparent waterproof and moisture-permeable film has a thickness of 60 μm to 100 μm.

7. Use of the transparent waterproof and breathable film according to claim 5 or 6 in optical display devices, decorations, medical devices, electronic screens or smart wearable devices.

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