Breathable waterproof membrane

Abstract

A breathable waterproof membrane is made by electrospinning a liquid and processing, and the liquid includes a first additive and a second additive. The first additive includes a nylon copolymer and a first alcohol solvent. The second additive is made by reacting a composition in a second alcohol solvent, wherein the composition includes a polysiloxane diol, a dihydric alcohol, and an isocyanate, and the dihydric alcohol includes an alkyl diol, a polyester diol, or a combination thereof. The breathable waterproof membrane of the present disclosure has high breathability, high waterproofness, and high softness.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a functional film, and particularly relates to a breathable waterproof film. BACKGROUND

[0002] In recent years, in addition to the design requirements in appearance, the textile technology is also developed to incorporate technology to enhance the functionality of clothing. Breathable waterproof fabric, as a functional fabric, can release the moisture on the surface of the human body when worn, and block the moisture from the external environment from entering the fabric, thereby being widely used in outdoor leisure clothing. The common method for making breathable waterproof fabric is to add water repellent agent to the breathable film, and then attach the film to the surface of the breathable fabric. However, the conventional water repellent agent often contains fluorine which is harmful to the environment, and if the water repellent agent does not contain fluorine, it is difficult to achieve good water repellency. Therefore, how to provide a breathable waterproof fabric with high breathability and high waterproofness is an active research topic in the field. SUMMARY

[0003] The present disclosure provides a breathable waterproof film with high breathability, high waterproofness, and high softness.

[0004] According to some embodiments of the present disclosure, a breathable waterproof film is made by electrospinning a spinning solution and processing, and the spinning solution includes a first additive and a second additive. The first additive includes a nylon copolymer and a first alcohol solvent. The second additive is made by reacting a composition in a second alcohol solvent, wherein the composition includes a polysiloxane diol, a dihydric alcohol, and an isocyanate, and the dihydric alcohol includes an alkyl diol, a polyester diol, or a combination thereof.

[0005] In some embodiments of the present disclosure, the alkyl diol is a C4-C18 alkyl diol.

[0006] In some embodiments of the present disclosure, the isocyanate includes isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, or a combination thereof.

[0007] In some embodiments of the present disclosure, the polyester diol has a weight average molecular weight of 1000 to 3000 daltons.

[0008] In some embodiments of the present disclosure, the composition can further include a chain extender, and the chain extender includes hydrazine, a diamino sulfonate, a hydroxyl-containing amine, or a combination thereof.

[0009] In some embodiments of the present disclosure, the diamino sulfonate is 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt.

[0010] In some embodiments of the present disclosure, the first alcohol solvent and the second alcohol solvent each comprises a lower aliphatic alcohol.

[0011] In some embodiments of the present disclosure, the average pore size of the breathable waterproof membrane is 0.5 to 1.5 microns, and the average fiber diameter of the breathable waterproof membrane is not greater than 800 nanometers.

[0012] In some embodiments of the present disclosure, the water contact angle of the breathable waterproof membrane is 100 to 140 degrees.

[0013] In some embodiments of the present disclosure, the water pressure resistance value of the breathable waterproof membrane is not less than 4000 mmH2O, and the air permeability of the breathable waterproof membrane is not less than 0.5 cubic feet / minute.

[0014] According to the above embodiments of the present disclosure, the breathable waterproof membrane of the present disclosure is prepared by electrospinning and processing of an electrospinning solution. By formulating the first additive in the electrospinning solution, the electrospinning solution can form nanofibers with suitable fiber fineness, so that the breathable waterproof membrane has a suitable pore size; by formulating the second additive in the electrospinning solution, the electrospinning solution can form nanofibers with high water repellency and high softness. In this way, it helps to improve the air permeability, waterproofness and softness of the breathable waterproof membrane as a whole. In addition, since the electrospinning solution does not contain fluorine and toxic solvents harmful to the environment, the breathable waterproof membrane prepared from the electrospinning solution also has environmental friendliness. DETAILED DESCRIPTION

[0015] In this document, sometimes the structure of a polymer or a group is represented in a skeleton formula. This representation can omit carbon atoms, hydrogen atoms, and carbon-hydrogen bonds. Of course, if the structure formula explicitly depicts an atom or group of atoms, the depiction is controlling.

[0016] The present disclosure provides a breathable waterproof membrane which can be applied in the field of textiles and is prepared by electrospinning and processing of an electrospinning solution. By adjusting the formulation in the electrospinning solution, the breathable waterproof membrane can have high air permeability, high waterproofness and high softness. In addition, since the electrospinning solution does not contain fluorine and toxic solvents harmful to the environment, the breathable waterproof membrane prepared from the electrospinning solution also has environmental friendliness.

[0017] In particular, the breathable waterproof membrane of the present disclosure is made by electrospinning an electrospinning solution and processing. For example, the electrospinning solution can be electrospun by an electrospinning process to form a plurality of nanofibers arranged in a staggered manner, and the plurality of nanofibers can be pressed by a hot pressing process to form the breathable waterproof membrane of the present disclosure. In the present disclosure, the electrospinning solution for forming the breathable waterproof membrane includes a first additive and a second additive. By the formulation of the first additive and the second additive, the breathable waterproof membrane can have high breathability, high waterproofness, high softness, and environmental friendliness. In detail, the first additive includes a nylon copolymer and a first alcohol solvent, and the second additive is prepared by reacting a composition in a second alcohol solvent, wherein the composition includes a polysiloxane diol, a dihydric alcohol, and an isocyanate, and the dihydric alcohol includes an alkyl diol, a polyester diol, or a combination thereof. The first additive and the second additive will be described in detail below.

[0018] For the first additive, the nylon copolymer in the first additive can be used to form a matrix material in the breathable waterproof membrane. In some embodiments, when a nylon copolymer with high wear resistance is used as a matrix material in the breathable waterproof membrane, the breathable waterproof membrane can have good wear resistance, thereby being suitable for use in outdoor functional clothing (e.g., mountaineering clothing). In some embodiments, the nylon copolymer may, for example, be a copolymer of a copolyamide and an alkoxyl-modified nylon 46 / 66 copolymer, so as to be soluble in the first alcohol solvent, thereby improving the spinnability of the electrospinning solution.

[0019] The first alcohol solvent in the first additive can make the electrospinning solution suitable for an electrospinning process, for example, a needleless electrospinning process, thereby quickly spinning to form a plurality of nanofibers arranged in a staggered manner. In some embodiments, the first alcohol solvent can include a lower aliphatic alcohol (i.e., an aliphatic alcohol with a carbon number of 1 to 5), for example, methanol, ethanol, propanol, or a combination thereof, thereby having easy volatility, and the above-mentioned lower aliphatic alcohol can make other formulations in the electrospinning solution well dissolved, so that the electrospinning solution can be in a uniform and non-precipitated state, thereby having good spinnability, and being conducive to forming nanofibers with suitable fiber fineness. For example, the solubility of the nylon copolymer in the first alcohol solvent can be 5 wt% to 15 wt%. In a preferred embodiment, the first alcohol solvent may, for example, be ethanol, thereby having easy volatility, low toxicity, and low corrosivity, so that the electrospinning solution has environmental friendliness. In some embodiments, in the first additive, the content of the nylon copolymer can be 5 parts by weight to 15 parts by weight, and the content of the first alcohol solvent can be 85 parts by weight to 95 parts by weight. The above-mentioned ratio is conducive to making the electrospinning solution form nanofibers with suitable fiber fineness, thereby further improving the breathability and waterproofness of the breathable waterproof membrane.

[0020] The second additive is prepared by reacting the composition in the second alcoholic solvent, and the composition includes a polysiloxane diol, a dihydric alcohol, and an isocyanate. In detail, the second additive having high water repellency is formed by the chemical reaction between the hydroxyl groups in the polysiloxane diol and the dihydric alcohol and the isocyanate groups in the isocyanate. The second additive can further react with the nylon copolymer in the first additive to graft onto the surface of the nylon copolymer (i.e., the matrix material in the breathable waterproof membrane), thereby forming a three-dimensional dendritic molecular structure, which can improve the water contact angle of the breathable waterproof membrane and provide the breathable waterproof membrane with high waterproofness. Specifically, in some embodiments, the water contact angle of the breathable waterproof membrane can be 100 to 140 degrees, thereby achieving good waterproofness. In some embodiments, the content of the polysiloxane diol is 30 to 70 parts by weight, the content of the dihydric alcohol is 10 to 30 parts by weight, and the content of the isocyanate is 100 to 150 parts by weight. The above-mentioned proportions help to form the second additive having a long straight chain molecular pattern and improve the yield.

[0021] In some embodiments, the second alcoholic solvent can include a lower aliphatic alcohol such as methanol, ethanol, propanol, or a combination thereof, thereby having easy volatility, and the lower aliphatic alcohol can well dissolve other formulations in the electrospinning solution, so that the electrospinning solution can exhibit a uniform and non-precipitated state and have good spinnability, which is conducive to forming nanofibers with suitable fiber fineness. In a preferred embodiment, the second alcoholic solvent can be the same as the first alcoholic solvent, thereby reducing the complexity of the reaction and improving the operation convenience of subsequent other processes (e.g., hot pressing process). In a more preferred embodiment, the second alcoholic solvent and the first alcoholic solvent are both ethanol, thereby providing excellent solubility and reactivity of the formulations in the first additive and the second additive.

[0022] For the polysiloxane diol in the composition, the siloxane segment in the polysiloxane diol can provide high hydrophobicity, high oleophobicity, and high temperature resistance. In some embodiments, the polysiloxane diol can have a structure as shown in formula (1):

[0023] wherein n can be an integer of 16 to 24. Based on the long chain structure of formula (1), the second additive formed from the composition can have high hydrophobicity, which is conducive to improving the waterproofness of the breathable waterproof membrane. On the other hand, since there are only two hydroxyl groups in the polysiloxane diol that can react with the isocyanate, it is helpful to make the subsequently formed second additive have a long straight chain molecular pattern, so that the second additive forms a three-dimensional dendritic molecular structure after grafting onto the surface of the nylon copolymer to provide high water repellency.

[0024] The diol of the present disclosure includes an alkyl diol, a polyester diol, or a combination thereof for the diol in the composition, thereby improving the reactivity of the overall composition and helping to extend the chain length of the second additive to form a three-dimensional dendritic molecular structure after grafting on the surface of the nylon copolymer to provide high water repellency. In some embodiments, the alkyl diol can be a C4-C18 alkyl diol, thereby helping to extend the chain length of the second additive. In detail, if the carbon number of the alkyl diol is less than 4, the effect of extending the chain length of the second additive by adding the alkyl diol is limited; if the carbon number of the alkyl diol is greater than 18, it is easy to cause the chain of the second additive to be excessively bent or intertwined, and it is not easy to form a three-dimensional dendritic molecular structure after grafting on the surface of the nylon copolymer. In some embodiments, the alkyl diol can be a linear alkyl diol, such as 1,4-butanediol. In addition, when the carbon number of the alkyl diol is high (for example, when the carbon number is greater than 12), the alkyl diol can preferably be a branched alkyl diol, thereby reducing the possibility of the chain of the second additive being excessively bent or intertwined, and facilitating the second additive to form a three-dimensional dendritic molecular structure after grafting on the surface of the nylon copolymer. In some embodiments, the weight average molecular weight of the polyester diol can be 1000-3000 Dalton, thereby having better reactivity and helping to extend the chain length of the second additive. In detail, if the weight average molecular weight of the polyester diol is less than 1000 Dalton, the effect of extending the chain length of the second additive by adding the alkyl diol is limited; if the weight average molecular weight of the polyester diol is greater than 3000 Dalton, it is easy to cause insufficient reactivity. Similarly, since there are only two hydroxyl groups in the diol that can react with isocyanate, it is helpful to make the second additive subsequently formed have a long straight chain molecular pattern, thereby forming a three-dimensional dendritic molecular structure after grafting on the surface of the nylon copolymer to provide high water repellency.

[0025] For the isocyanate in the composition, the isocyanate can be connected to the polysiloxane diol and the dihydric alcohol to form the second additive having a long straight chain molecular pattern. In some embodiments, the isocyanate can be an aromatic isocyanate, such as diphenyl methane diisocyanate (MDI). In other embodiments, the isocyanate can be an aliphatic isocyanate, such as isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), or a combination thereof. In yet other embodiments, the isocyanate can be a combination of an aliphatic isocyanate and an aromatic isocyanate. As such, since only two isocyanate groups in the isocyanate described above can react with the hydroxyl groups in the polysiloxane diol and the dihydric alcohol, it is helpful to form the second additive having a long straight chain molecular pattern, thereby forming a three-dimensional dendritic molecular structure after being grafted to the surface of the nylon copolymer to provide high water repellency.

[0026] In some embodiments, the composition can further include a chain extender. The chain extender can form a branch on the main chain structure of the second additive, thereby forming a three-dimensional dendritic molecular structure after being grafted to the surface of the nylon copolymer to provide high water repellency. In some embodiments, the chain extender can include hydrazine, a diamino sulfonate salt, a hydroxyl-containing amine, or a combination thereof. In some embodiments, the diamino sulfonate salt can be, for example, 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt (EES-200L, trade name, available from Polyone International Co., Ltd.) for better results.

[0027] Further, regarding the method of preparing the second additive, in some embodiments, the polysiloxane diol, the dihydric alcohol, and the isocyanate can be dissolved in ethanol, and the temperature can be increased to perform a prepolymerization reaction under the catalysis of a catalyst. Subsequently, the temperature can be decreased, and an appropriate amount of acetone can be added for dispersion, and a chain extender can be added for chain extension. Then, ethanol (e.g., ethanol having a volume percentage concentration of greater than 95%) can be added for dispersion, and the acetone can be removed by fractional distillation to obtain the second additive dissolved in ethanol. Subsequently, the first additive and the second additive can be mixed to form an electrospinning solution, and the electrospinning solution can be used for spinning processing to obtain the breathable waterproof membrane of the present disclosure.

[0028] In general, by the formulation of the first additive in the electrospinning solution, the electrospinning solution can form nanofibers with suitable fiber fineness, so that the breathable waterproof membrane has suitable pore size, thereby helping to improve the breathability, waterproofness and softness of the breathable waterproof membrane; and by the formulation of the second additive in the electrospinning solution, the electrospinning solution can form nanofibers with high water repellency and high softness, thereby helping to improve the breathability, waterproofness and softness of the breathable waterproof membrane. In other words, by the design on the physical (fiber fineness, pore size) and chemical (water repellency of the material) levels, the breathable waterproof membrane of the present disclosure can have breathability, waterproofness and softness. In some embodiments, the average pore size of the breathable waterproof membrane can be 0.5 to 1.5 microns, and the average fiber diameter of the breathable waterproof membrane can be no more than 800 nanometers. In some embodiments, the water pressure resistance value of the breathable waterproof membrane can be no less than 4000 mmH2O, and the air permeability of the breathable waterproof membrane can be no less than 0.5 cubic feet / minute. In addition, the second additive of the present disclosure does not contain fluorine, and can be considered as a fluorine-free water repellent. Unlike conventional fluorine-free water repellents, the fluorine-free water repellent of the present disclosure is alcohol-soluble, so the subsequent heat treatment time can be greatly shortened, and environmental friendliness can also be considered.

[0029] In the following description, various evaluations will be made on the breathable waterproof membrane of the present disclosure to specifically describe the efficacy of the present disclosure. It should be understood that the materials used, their contents and proportions, processing details and processing procedures, etc. can be appropriately changed without exceeding the scope of the present disclosure. Therefore, the present disclosure should not be limitedly interpreted by the examples described below.

[0030] <Experimental Example 1: Average fiber diameter of nanofibers in breathable waterproof membrane>

[0031] In this experimental example, a scanning electron microscope (SEM) was used to observe the breathable waterproof membrane of Example 1 at a magnification sufficient for measurement (e.g., 3000x or less, 4000x to 6000x, 10000x to 20000x), and the fiber diameters of a plurality of nanofibers therein were measured and averaged to obtain the average fiber diameter of the nanofibers in the breathable waterproof membrane. The first additive in the electrospinning solution used to prepare the breathable waterproof membrane of Example 1 included a copolymer of co-polyamide and alkoxyl-modified nylon 46 / 66 copolymer and ethanol, and the composition used to form the second additive was reacted in ethanol, wherein the composition included a polysiloxane diol as shown in formula (1), 1,4-butanediol and isophorone diisocyanate. The measurement results are shown in Table 1.

[0032] Table 1

[0033]

[0034] From the results of Table 1, it can be seen that the average fiber diameter of the nanofibers in the breathable waterproof membrane of Example 1 is about 283 nm, and the proportion of nanofibers with a fiber diameter of 250 nm to 349 nm is as high as 90%. It can be seen that the nanofibers in the breathable waterproof membrane of the present disclosure have a suitable average fiber diameter and a concentrated fiber diameter, thereby balancing the air permeability and waterproofness of the breathable waterproof membrane.

[0035] <Experimental Example 2: Water contact angle test of breathable waterproof membrane>

[0036] In this experimental example, 0.006 mL of water was dropped on the surface of the breathable waterproof membrane of Example 1 using a dropper, then the image was captured and the water contact angle of the breathable waterproof membrane was measured. The results show that the water contact angle of the breathable waterproof membrane is 131 degrees. It can be seen that the breathable waterproof membrane of the present disclosure has a certain waterproofness.

[0037] <Experimental Example 3: Air permeability test of breathable waterproof membrane>

[0038] In this experimental example, the air permeability test of the breathable waterproof membrane of Example 1 was performed using the standard method ASTM D737. The test results show that the breathable waterproof membrane of Example 1 has an air permeability of 1.8 cubic feet per minute (CFM), which is much better than the air permeability of many breathable waterproof membranes on the market (0.5 CFM).

[0039] <Experimental Example 4: Waterproofness test of breathable waterproof membrane>

[0040] In this experimental example, the breathable waterproof membrane of Example 1 was arranged on the surface of a nylon base cloth with a basis weight of 15 gsm, and the breathable waterproof membrane arranged on the nylon base cloth was subjected to five water pressure resistance tests using the standard method JIS L1092; in addition, the water vapor resistance test of the breathable waterproof membrane arranged on the nylon base cloth was performed using the standard method CNS 15102L3256. The results show that the water pressure resistance value of the breathable waterproof membrane is greater than 4000 mm of water column, and the water vapor resistance value of the breathable waterproof membrane is 2. It can be seen that the breathable waterproof membrane of the present disclosure has high waterproofness.

[0041] <Experimental Example 5: Rainwater penetration measurement test of breathable waterproof membrane>

[0042] In this experimental example, the breathable waterproof membrane of Example 1 was arranged on the surface of a nylon base cloth with a basis weight of 10 gsm, and the rainwater penetration measurement test of the breathable waterproof membrane arranged on the nylon base cloth was performed using the standard method AATCC35. The results show that the rainwater penetration amount is 0.2 grams, which is much better than the standard index (1 gram). It can be seen that the breathable waterproof membrane of the present disclosure can effectively achieve the effect of preventing rainwater penetration.

[0043] <Experimental Example 6: Softness test of the breathable waterproof membrane>

[0044] In this experimental example, the softness test of the breathable waterproof membrane of Example 1 was performed using the standard method CNS5610, and the result showed that the softness of the breathable waterproof membrane was 1 Newton / cm; in addition, the breathable waterproof membrane of Example 1 was arranged on the surface of a nylon base cloth with a basis weight of 10 gsm, and the softness test of the breathable waterproof membrane arranged on the nylon base cloth was also performed using the standard method CNS12915, and the result showed that the softness of the breathable waterproof membrane arranged on the nylon base cloth was 2 Newton / cm. It can be seen that the breathable waterproof membrane of the present disclosure has good softness.

[0045] <Experimental Example 7: Water washing resistance test of the breathable waterproof membrane>

[0046] In this experimental example, the breathable waterproof membrane of Example 1 was arranged on the surface of a nylon base cloth with a basis weight of 20 gsm, and the water washing resistance test of the breathable waterproof membrane arranged on the nylon base cloth was performed using the standard method AATCC135 to obtain the water pressure value and the air permeability of the breathable waterproof membrane after washing, and the test results are shown in Table 2.

[0047] Table 2

[0048]

[0049]

[0050] Table 2 shows that the breathable waterproof membrane arranged on the nylon base cloth can still maintain good waterproofness and air permeability after 50 times of washing, and it can be seen that the breathable waterproof membrane of the present disclosure has good water washing resistance, thereby having wide application.

[0051] According to the above embodiments of the present disclosure, the breathable waterproof membrane of the present disclosure is prepared by electrospinning liquid spinning and processing. Through the preparation of the first additive in the electrospinning liquid, the electrospinning liquid can form nanofibers with suitable fiber fineness, so that the breathable waterproof membrane has a suitable pore size; through the preparation of the second additive in the electrospinning liquid, the electrospinning liquid can form nanofibers with high water repellency and high softness. In this way, it is helpful to improve the air permeability, waterproofness and softness of the breathable waterproof membrane as a whole. In addition, since the electrospinning liquid does not contain fluorine and toxic solvents which are harmful to the environment, the breathable waterproof membrane prepared from the electrospinning liquid also has environmental friendliness.

[0052] Although the present disclosure has been disclosed in the above embodiments, it is not intended to limit the present disclosure, and any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present disclosure, and therefore the protection scope of the present disclosure shall be subject to the appended claims.

Claims

1. A breathable and waterproof membrane, characterized in that, It is prepared by spinning and processing with an electrospinning solution, wherein the electrospinning solution comprises: The first additive comprises a nylon copolymer and a first alcohol solvent; and The second additive is prepared by reacting a composition in a second alcohol solvent, wherein the composition comprises: Polysiloxane diol; Diols, including alkyl glycols, polyester glycols, or combinations thereof; and Isocyanates.

2. The breathable and waterproof membrane as described in claim 1, characterized in that, The alkyl diol is a C4 to C18 alkyl diol.

3. The breathable and waterproof membrane as described in claim 1, characterized in that, The isocyanate includes isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, or combinations thereof.

4. The breathable and waterproof membrane as described in claim 1, characterized in that, The polyester diol has a weight average molecular weight of 1,000 to 3,000 Daltons.

5. The breathable and waterproof membrane as described in claim 1, characterized in that, The composition further includes a chain extender, and the chain extender includes hydrazine, diaminosulfonates, hydroxylamines, or combinations thereof.

6. The breathable and waterproof membrane as described in claim 5, characterized in that, The diaminosulfonates are sodium 2-[(2-aminoethyl)amino]ethanesulfonate.

7. The breathable and waterproof membrane as described in claim 1, characterized in that, The first alcohol solvent and the second alcohol solvent each comprise lower fatty alcohols.

8. The breathable and waterproof membrane as described in claim 1, characterized in that, The average pore size of the breathable and waterproof membrane is 0.5 micrometers to 1.5 micrometers, and the average fiber diameter of the breathable and waterproof membrane is no greater than 800 nanometers.

9. The breathable and waterproof membrane as described in claim 1, characterized in that, The water contact angle of the breathable and waterproof membrane is 100 to 140 degrees.

10. The breathable and waterproof membrane as described in claim 1, characterized in that, The breathable and waterproof membrane has a water pressure resistance of not less than 4000 mm water column and an air permeability of not less than 0.5 cubic feet per minute.

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