Nanomembrane, waterproof ventilation sheet comprising same, and method for manufacturing nanomembrane

Abstract

The present invention relates to a waterproof sheet having improved waterproofness and air permeability by adjusting the electrical conductivity of an electrospinning solution to adjust the size of micropores of a nanomembrane. The present invention relates to a nanomembrane formed of synthetic fibers including polyvinylidene fluoride and a metal complex dye, and having a water pressure resistance of 5,000-15,000 mmH2O.

Description

Nano membrane, waterproof breathable sheet including the same, and method for manufacturing the nano membrane

[0001] The present invention relates to a nano membrane, a waterproof breathable sheet including the same, and a method for manufacturing the nano membrane.

[0002] Various electronic devices, such as mobile devices, hearing aids, communication equipment such as walkie-talkies, and automobile headlamps, require waterproof performance to prevent water / liquid from penetrating the electronic device and dustproof performance to prevent contamination / dust from penetrating the electronic device, while maintaining pressure equilibrium inside / outside the electronic device by providing breathability to the electronic device. Accordingly, the electronic devices include waterproof breathable sheets that have both waterproof / dustproof and breathable properties.

[0003] In particular, electronic devices such as the above mobile devices are being used more frequently as they have various performances and functions added, and so they are required to have not only waterproof / dustproof functions in various environments but also acoustic performance that transmits sound in a form close to the original sound without distortion.

[0004] Recently, as the demand for mobile devices in underwater environments in both winter and summer increases, there is a growing demand for high-spec waterproof performance in various environments.

[0005] Accordingly, there is still a need for a waterproof, breathable sheet that maintains excellent waterproof properties even when exposed to various environmental conditions.

[0006] The problem to be solved by the present invention is to provide a nano membrane with improved waterproofness and breathability under room temperature, low temperature, thermal shock, and high temperature and high humidity conditions, a waterproof breathable sheet including the same, and a method for manufacturing the same.

[0007] In addition, another problem to be solved by the present invention is to improve the waterproofness and breathability of the breathable sheet by controlling the electrical conductivity of the electrospinning solution and thereby controlling the micropore size of the nano membrane.

[0008] One embodiment of the present invention is a nano membrane formed of synthetic fibers including polyvinylidene fluoride and a metal complex dye, and having a water pressure resistance of 5,000 to 15,000 mmH2O.

[0009] In the present invention, the metal complex dye may be solvent black.

[0010] In the present invention, the solvent black may be at least one selected from the group consisting of solvent black 3, solvent black 5, solvent black 7, solvent black 22, solvent black 27, solvent black 28, solvent black 34, solvent black 45, and solvent black 46.

[0011] In the present invention, the synthetic fiber may contain 0.2 to 5 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride.

[0012] In the present invention, the diameter of the synthetic fiber may be 0.1 to 1 μm.

[0013] In the present invention, the nano membrane may have a pore size of 1.5 μm or less.

[0014] Another embodiment of the present invention is a waterproof breathable sheet comprising the nano membrane, having a water resistance that does not leak for more than 30 minutes at a water pressure of 5 m or more at room temperature (20°C±5°C), and having an acoustic transmission loss of less than 5 dB at 1000 Hz.

[0015] In the present invention, the waterproof breathable sheet may not leak for more than 30 minutes at a water pressure of 5 m or more under the following low temperature conditions, may not leak for more than 30 minutes at a water pressure of 5 m or more under the following high temperature conditions, and may not leak for more than 30 minutes at a water pressure of 5 m or more under the following thermal shock conditions.

[0016] [Low temperature conditions]

[0017] Before measuring the water leakage, expose the waterproof breathable sheet to a temperature of -20℃ for 72 hours.

[0018] [High temperature conditions]

[0019] Before measuring the water leakage, expose the above waterproof breathable sheet to a temperature of 50℃ and 95% humidity for 72 hours.

[0020] [Thermal shock conditions]

[0021] The cycle of exposure to temperatures of -40℃ and 85℃ for 1 hour each was repeated 30 times before measuring the leak.

[0022] Another embodiment of the present invention is a method for manufacturing a nano membrane, comprising the steps of: preparing a spinning solution obtained by mixing polyvinylidene fluoride and a metal complex dye; and electrospinning the spinning solution to obtain a nano membrane in which synthetic fibers are integrated in the form of a nonwoven fabric including a plurality of pores; and having a water pressure resistance of 5,000 to 15,000 mmH2O.

[0023] In the present invention, the metal complex dye is solvent black.

[0024] In the present invention, the radiation solution may contain 0.2 to 5 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride.

[0025] In the present invention, the electrical conductivity of the above-mentioned radiation solution may be 30 to 200 μS / cm.

[0026] The present invention can improve waterproofness by controlling the pore size of the nano membrane by adding solvent black.

[0027] In addition, the present invention can improve waterproofness under low temperature, high temperature, thermal shock, and high temperature and high humidity conditions without reducing acoustic loss and air permeability by electrospinning a spinning solution having controlled electrical conductivity including solvent black.

[0028] FIG. 1 is a drawing schematically showing the structure of a waterproof breathable sheet according to an embodiment of the present invention.

[0029] FIG. 2 is a drawing schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0030] FIG. 3 is a drawing schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0031] FIG. 4 is a drawing schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0032] Hereinafter, the terms "upper" or "upper" may include not only things directly above in contact but also things above in a non-contact manner. Singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather includes other components, unless otherwise specifically stated.

[0033] The use of the term "above" and similar referential terms may refer to both the singular and the plural. Unless the steps of a method are explicitly stated or contradicted, the steps may be performed in any order, and the order stated is not necessarily limited to that order.

[0034] As used herein, the terms "comprise," "comprising," "formed," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus comprising a list of elements is not necessarily limited to only those elements, but may also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, unless expressly stated to the contrary, "or" is an inclusive or and not an exclusive or.

[0035] Additionally, when the terms “about,” “approximately,” or similar expressions such as “at least” are used in connection with a numerical value herein, it is intended that the numerical value be allowed a theoretical, experimental, statistical, or empirical error of ±10%, ±7%, ±5%, ±3%, ±2%, or ±1% based on that numerical value.

[0036] Any use of examples or exemplary terms is merely intended to elaborate technical ideas and is not intended to limit the scope of the invention unless otherwise defined by the claims.

[0037]

[0038] Figure 1 shows a schematic diagram of a waterproof breathable sheet according to one embodiment of the present invention.

[0039] Referring to Fig. 1, the waterproof breathable sheet (10) includes a nano membrane (100) and a first adhesive portion (110). At this time, the first adhesive portion (110) is provided on one surface of the nano membrane (100).

[0040] The above adhesive portion (110) may be provided along a portion of one side of the nano membrane (100), for example, along the edge of the nano membrane (100), and an area of ​​one side of the nano membrane (100) on which the first adhesive portion (110) is provided, where the first adhesive portion (110) is not provided, forms a ventilation area (B1) through which air can pass.

[0041] The above first adhesive portion (110) may be composed of a single layer or a multilayer of three or more layers in which adhesive is laminated on both sides of the substrate.

[0042] In the present invention, the first adhesive portion (110) may include a substrate (111) and a first adhesive layer (112) and a second adhesive layer (113) provided on both sides of the substrate.

[0043] The first adhesive layer (112) is interposed between the substrate (111) and the nano membrane (100), thereby ensuring a firm bond between the substrate (111) and the nano membrane (100).

[0044] The first adhesive layer (112) may be any known adhesive that can ensure a strong bond between the nano membrane (100) and the substrate (111), without limitation. For example, an epoxy adhesive, a urethane adhesive, an acrylic adhesive, a thermosetting adhesive, or a petroleum resin adhesive may be used.

[0045] The above second adhesive layer (113) can ensure a firm bond between the substrate (111) and the components of the electronic device to which the waterproof breathable sheet (10) is applied.

[0046] The second adhesive layer (113) may be any known adhesive that can ensure a firm bond between the substrate (111) and components of an electronic device, and for example, an epoxy adhesive, a urethane adhesive, an acrylic adhesive, a thermosetting adhesive, or a petroleum resin adhesive may be used.

[0047] In the present invention, the first adhesive layer (112) and the second adhesive layer (113) may include the same or different adhesives. For example, the first adhesive layer (112) and the second adhesive layer (113) may use the same adhesive, for example, an acrylic adhesive.

[0048] The above substrate (111) may be used without limitation as long as it can function as a carrier for the adhesive layer (112, 113) in the form of a film, sheet, or foam. For example, the substrate (111) may include a polyester-based substrate, a polyurethane-based substrate, a polyethylene-based substrate, a polyolefin-based substrate, or a combination thereof. For example, the substrate may be a polyurethane foam or a polyolefin foam.

[0049] The above-mentioned substrate (111) may be a single-layer film or a single-layer sheet, but is not limited thereto, and may be a multi-layer laminate in which multiple films or sheets are laminated.

[0050] By providing the aforementioned adhesive portion (110) on one side of the nano membrane (100), the waterproof breathable sheet (10) and the electronic device are firmly bonded, so that the waterproofness can be improved without reducing the sound permeability of the electronic device.

[0051] The above nano membrane (100) will be described later.

[0052] Figure 2 is a schematic diagram of a waterproof ventilation sheet (20) according to another embodiment.

[0053] The above waterproof ventilation sheet (20) may have a structure in which two waterproof ventilation sheets are laminated.

[0054] Fig. 2 illustrates a structure in which two waterproof, breathable sheets are laminated, but two or more waterproof, breathable sheets may be laminated as needed.

[0055] It includes the above nano membrane (200) and a first adhesive portion (210) provided on one surface of the nano membrane.

[0056] In FIG. 2, the nano membrane (100) and the first adhesive portion (110) refer to the description in FIG. 1, and the contents regarding the nano membrane (200) and the first adhesive portion (210) also refer to the contents of the corresponding nano membrane (100) and the first adhesive portion (110) in the description in FIG. 1, respectively.

[0057] Figure 3 is a schematic diagram of a waterproof ventilation sheet (30) according to another embodiment.

[0058] The above waterproof breathable sheet (30) includes a nano membrane (300), a first adhesive portion (310) and a second adhesive portion (320) provided on both sides of the nano membrane (300), and a shock absorbing layer provided on the second adhesive portion.

[0059] Here, the content regarding the first adhesive portion (310) refers to the content of the corresponding first adhesive portion (110) in the description of FIG. 1.

[0060] The second adhesive portion (320) may be provided on a portion of the surface of the nano membrane (300) where the first adhesive portion (310) is not provided, for example, along the edge of the nano membrane (300), and the area of ​​the surface of the nano membrane (300) where the second adhesive portion (320) is not provided forms a ventilation area (B2) through which air can pass.

[0061] The above second adhesive portion (320) may be composed of a single layer or a multilayer of three or more layers in which adhesive is laminated on both sides of the substrate.

[0062] In the present invention, the second adhesive portion (320) may include a substrate (321) and a third adhesive layer (322) and a fourth adhesive layer (323) provided on both sides of the substrate.

[0063] The third adhesive layer (322) is interposed between the substrate (321) and the nano membrane (300), thereby ensuring a firm bond between the substrate (321) and the nano membrane (300).

[0064] The third adhesive layer (322) may be any known adhesive that can ensure a strong bond between the nano membrane (300) and the substrate (321), without limitation. For example, an epoxy adhesive, a urethane adhesive, an acrylic adhesive, a thermosetting adhesive, or a petroleum resin adhesive may be used.

[0065] The above fourth adhesive layer (323) can ensure a strong bond between the substrate (321) and the shock absorbing layer (330).

[0066] The fourth adhesive layer (323) may be used without limitation as long as it is a known adhesive that can ensure a strong bonding of the shock-absorbing layer (330). For example, an epoxy adhesive, a urethane adhesive, an acrylic adhesive, a thermosetting adhesive, or a petroleum resin adhesive may be used.

[0067] In the present invention, the third adhesive layer (322) and the fourth adhesive layer (323) may include the same or different adhesives. For example, the third adhesive layer (322) and the fourth adhesive layer (323) may use the same adhesive, for example, an acrylic adhesive.

[0068] The substrate (321) may be used without limitation as long as it can function as a carrier for the adhesive layer (322, 323) in the form of a film, sheet, or foam. For example, the substrate (321) may include a polyester-based substrate, a polyurethane-based substrate, a polyethylene-based substrate, a polyolefin-based substrate, or a combination thereof. For example, the substrate (321) may be a polyester film.

[0069] The above-mentioned substrate (321) may be a single-layer film or a single-layer sheet, but is not limited thereto, and may be a multi-layer laminate in which multiple films or sheets are laminated.

[0070] The above shock absorbing layer (330) is a functional layer that absorbs external shock and blocks energy transfer to the lower layer, and for example, an air-filled foam material, elastic rubber, and synthetic petroleum resin material can be used.

[0071] Examples of foam materials include polyurethane foam, polyolefin foam, and phenolic foam; synthetic petroleum resin materials include polypropylene and polyvinyl chloride; and rubber materials include natural rubber, latex, and nitrile butadiene rubber.

[0072] In the present invention, the shock absorbing layer (330) may include polyurethane foam.

[0073] The above shock-absorbing layer (330) may be composed of a single layer or multiple layers. When the above shock-absorbing layer (330) is composed of multiple layers, each layer may include at least one of the aforementioned foam materials, rubber, and synthetic petroleum resin materials.

[0074] Figure 4 is a schematic diagram of a waterproof ventilation sheet (40) according to another embodiment.

[0075] The above waterproof ventilation sheet (40) may have a structure in which two waterproof ventilation sheets are laminated.

[0076] The waterproof ventilation sheet (40) illustrated in FIG. 4 illustrates a structure in which two waterproof ventilation sheets described in FIG. 3 are laminated, but two or more waterproof ventilation sheets may be laminated as needed.

[0077] It includes the above nano membrane (400) and a first adhesive portion (410) and a second adhesive portion (420) provided on both sides of the nano membrane, and further includes a shock-absorbing layer (430) on the second adhesive portion (420).

[0078] In FIG. 4, the nano membrane (300), the first adhesive portion (310), the second adhesive portion (320), and the shock absorbing layer (330) refer to the description in FIG. 3, and the contents regarding the nano membrane (400), the first adhesive portion (410), the second adhesive portion (420), and the shock absorbing layer (430) also refer to the contents of the corresponding nano membrane (300), the first adhesive portion (310), the second adhesive portion (320), and the shock absorbing layer (330) in the description in FIG. 3.

[0079] In addition, the structure of a modified waterproof ventilation sheet, such as a waterproof ventilation sheet having a structure in which a waterproof ventilation sheet (30) described in FIG. 3 is laminated on a waterproof ventilation sheet (10) described in FIG. 1, is not specifically described, but is included in the present invention as an equivalent of the present invention.

[0080] Below, the nano membranes (100, 200, 300, 400) exemplified in FIGS. 1 to 4 are described in detail.

[0081]

[0082] In the present invention, the nano membrane can be manufactured by electrospinning a spinning solution obtained by mixing polyvinylidene fluoride and a metal complex dye.

[0083] In the present invention, the spinning solution may be a solution in which the main material constituting the synthetic fiber is dissolved in a solvent.

[0084] In the present invention, the solvent for dissolving the synthetic fiber raw material may include dimethylacetamide, dimethylacetone, dimethylsulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, trimethylphosphate, tetramethylurea, dimethylformamide, methyl ethyl ketone, tetrahydrofuran, or a combination thereof.

[0085] The synthetic fiber spinning solution may contain the synthetic fiber raw material in an amount of more than 5 wt% and less than 25 wt% based on solids, and preferably, the synthetic fiber raw material may contain 10 to 20 wt% based on solids. If the amount is less than 5 wt% based on solids, spinning may be difficult, and if it is more than 25 wt%, the desired electrical conductivity value may not be exhibited, water pressure resistance may decrease, and waterproofness may deteriorate.

[0086] In the present invention, the metal complex dye may be solvent black.

[0087] The above solvent black may be a powder made of powder.

[0088] In addition, the solvent black may be at least one selected from the group consisting of solvent black 3, solvent black 5, solvent black 7, solvent black 22, solvent black 27, solvent black 28, solvent black 34, solvent black 45, and solvent black 46, preferably at least one selected from the group consisting of solvent black 3, solvent black 27, and solvent black 28, and most preferably solvent black 28.

[0089] The above solvent black exhibits a black color in powder form and can be well dissolved in ethanol solvent.

[0090] In the present invention, the spinning solution may contain 0.2 to 5 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride, and preferably 0.5 to 3 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride. If the content of the metal complex dye is less than 0.2 parts by weight, the water resistance of the nano membrane may be reduced, and if it exceeds 5 parts by weight, the breathability may be reduced, the electrical conductivity may increase, and a film phase may be formed, so the above range is preferred.

[0091] In the present invention, when the metal complex dye is solvent black 28, the content of solvent black 28 may be 0.5 to 3 parts by weight relative to 100 parts by weight of polyvinylidene fluoride.

[0092] In addition, when the metal complex dye is solvent black 3, the content of solvent black 3 may be 1 to 5 parts by weight relative to 100 parts by weight of polyvinylidene fluoride. The spinning solution may have a viscosity of 100 to 3,000 cp, preferably 150 to 2,500 cp, 170 to 2,000 cp, or 190 to 1,800 cp, but is not necessarily limited thereto.

[0093] When the viscosity of the above spinning solution satisfies the above range, it is easy to manufacture synthetic fibers by electrospinning. When the viscosity is excessively high, it is difficult to control the discharge speed of the spinning solution, and a decrease in processability due to nozzle clogging is expected. When the viscosity is excessively low, it may be difficult to form fibers.

[0094] The electrical conductivity of the above-mentioned spinning solution may be 30 to 200 μS / cm, preferably 50 to 100 μS / cm. The electrical conductivity of the spinning solution can be adjusted within the above range by including the above-mentioned metal complex dye in a predetermined amount.

[0095] The nanomembrane according to the present invention is manufactured by electrospinning, and the electrical conductivity of the spinning solution is controlled by the voltage applied during the electrospinning process, thereby affecting the diameter of the final fibers and the pore distribution and shape of the membrane obtained from the fibers. By controlling the microstructure of the nanomembrane through such electrospinning conditions, a breathable sheet with excellent waterproofing and breathability can be manufactured.

[0096] In the present invention, the diameter of the synthetic fiber obtained by electrospinning the spinning solution may have a diameter of 0.1 to 1 μm. Preferably, the diameter of the synthetic fiber may be 0.3 to 0.9 μm.

[0097] By electrospinning the above-mentioned spinning solution, synthetic fibers containing a metal complex dye can be integrated into a nonwoven fabric form containing a large number of pores to form a nano membrane.

[0098] The above non-woven nano membrane contains a large number of pores, and the nano membrane has a porosity of 50 to 90% and a basis weight of 0.5 to 15 g / m. 2 It could be.

[0099] In addition, the nano membrane may have a pore size of 1.5 μm or less, preferably 1.2 μm or less, and more preferably 0.3 to 1.0 μm.

[0100] In the present invention, the synthetic fibers obtained through the electrospinning may contain 0.2 to 5 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride, and preferably 0.5 to 3 parts by weight of a metal complex dye relative to 100 parts by weight of polyvinylidene fluoride.

[0101] At least some of the above synthetic fibers may include a metal complex dye on their surface or within the fiber.

[0102] The nano membrane obtained by the above-described method contains a specific amount of solvent black, which is a metal complex dye having a specific metal content, and is manufactured by electrospinning it and integrating it into a non-woven fabric form, so that it can have the following physical properties.

[0103] In the present invention, the nano membrane has an air permeability of 1 to 10 cm as measured according to the ASTM D 737 measurement method. 3 / cm 2 / sec(ccs) and preferably 1 to 4 cm 3 / cm 2 It could be / sec(ccs).

[0104] In addition, in the present invention, the nano membrane may have a water pressure of 5,000 to 15,000 mmH2O, preferably 8,000 to 14,000 mmH2O, as measured according to the KS K ISO 811 measurement method.

[0105] In the present invention, the waterproof breathable sheet may further include a step of providing an adhesive portion on one or both sides of the nano membrane after manufacturing the nano membrane as described above.

[0106] The above adhesive portion may be provided by directly applying it onto the nano membrane, or by separately manufacturing the adhesive portion and then adhering it onto the nano membrane.

[0107] For the materials and specific configuration of the above adhesive portion, refer to the contents of the adhesive portion described in FIGS. 1 to 4.

[0108] In the present invention, the waterproof breathable sheet may further include a step of providing a shock-absorbing layer on at least one side of the adhesive portions after providing adhesive portions on one or both sides of the nano membrane as described above.

[0109] For the materials and specific configuration of the above shock absorbing layer, refer to the contents of the shock absorbing layer described in FIGS. 1 to 4.

[0110] In the present invention, the waterproof breathable sheet may have the following properties.

[0111] The above waterproof breathable sheet may have a breathability of at least 30 cc / min at 1 PSI pressure, preferably 30 to 80 cc / min or 40 to 75 cc / min.

[0112] The above waterproof breathable sheet has a water pressure waterproof property that does not leak for more than 30 minutes under a water pressure of 5 m or more at room temperature (20°C±5°C), and may have an acoustic transmission loss of less than 5 dB at 1,000 Hz, and preferably has a water pressure waterproof property that does not leak for more than 70 minutes under a water pressure of 5 m or more at room temperature (20°C±5°C), and may have an acoustic transmission loss of less than 1.5 dB at 1,000 Hz.

[0113] In addition, in the present invention, the waterproof breathable sheet may not leak for more than 30 minutes at a water pressure of 5 m or more under the following low temperature conditions, may not leak for more than 30 minutes at a water pressure of 5 m or more under the following high temperature conditions, and may not leak for more than 30 minutes at a water pressure of 5 m or more under the following thermal shock conditions. Preferably, the waterproof breathable sheet may not leak for more than 70 minutes at a water pressure of 5 m or more under the above low temperature conditions, may not leak for more than 50 minutes at a water pressure of 5 m or more under the above high temperature conditions, and may not leak for more than 60 minutes at a water pressure of 5 m or more under the above thermal shock conditions.

[0114] [Low temperature conditions]

[0115] Before measuring the water leakage, expose the waterproof breathable sheet to a temperature of -20℃ for 72 hours.

[0116] [High temperature conditions]

[0117] Before measuring the water leakage, expose the above waterproof breathable sheet to a temperature of 50℃ and 95% humidity for 72 hours.

[0118] [Thermal shock conditions]

[0119] The cycle of exposure to temperatures of -40℃ and 85℃ for 1 hour each was repeated 30 times before measuring the leak.

[0120] The waterproof breathable sheet of the present invention can be used in electronic devices that require both waterproofing and breathability, such as mobile phones, portable pads, speakers, microphones, and other audio devices.

[0121] Hereinafter, the present invention will be described in more detail through specific examples, and the present invention is not limited to the following examples.

[0122] The evaluation methods used in the following examples and comparative examples are as follows.

[0123]

[0124] Evaluation method

[0125] (1) Unit weight: ASTM D 3776

[0126] (2) Electrical conductivity: KS C IEC 60746-3

[0127] (3) Air permeability: Measured under the conditions of an area of ​​38㎠ and a static pressure of 125Pa using the ASTM D 737 method.

[0128] (4) Water pressure: Apply KS K ISO 811 low-pressure method to apply pressure at 2,000 mmH2O / min over an area of ​​100 ㎠ and measure the pressure at the point where the first water droplet appears.

[0129] (5) Thickness: Thickness measurement according to KS K 0506 or ISO 4593 and ISO 9073-2

[0130] (6) Acoustic transmission loss: Evaluated by acoustic transmission loss test at 1,000 Hz according to ASTM E-2611-09.

[0131] (7) Water pressure resistance: Use a water pressure measuring device that can apply a constant water pressure of 0 to 20 m depth for a certain period of time as used in KS K ISO 811. For low temperature evaluation, evaluation is performed after pretreatment at -20 ℃ for 72 hours, for high temperature / high humidity conditions, evaluation is performed after pretreatment at 50 ℃ and 95% humidity for 72 hours, and for thermal shock conditions, evaluation is performed after repeating 30 cycles of maintaining -40 ℃ and 85 ℃ for 1 hour each, and then evaluation is performed under room temperature (20 ℃ ± 5 ℃) conditions.

[0132] (8) Air permeability: Measure the flow rate of air passing through a circular area of ​​1 mm in diameter for 1 minute under 1 PSI pressure using the gas permeability method of a capillary flow porosimeter.

[0133] (9) Porosity: Porosity (%) = [1 - (A / B)] x 100 = {1 - [(C / D) / B]} x 100,

[0134] (A = density of nanomembrane, B = density of nanomembrane polymer, C = weight of nanomembrane, D = volume of nanomembrane)

[0135] (10) Pore size: ASTM F316 applied, using the average pore size value measured using a CFP (Capilary flow porometer)

[0136] (11) Electrical conductivity: KCl_0_01M Standard type applied, 0.01M KCl, 1413μS / cm - 25 °C analysis, average of 2 measurements

[0137]

[0138] Solvent black

[0139] Solvent Black 3, Solvent Black 27 and Solvent Black 28 in powder form were prepared.

[0140]

[0141] Examples 1 to 6

[0142] Polyvinylidene fluoride (PVdf), a synthetic fiber raw material, was dissolved in dimethylacetamide solvent, and then solvent black was added to prepare a spinning solution.

[0143] The above-mentioned spinning solution was electrospun using an electrospinning device at a voltage of 55 kV and a discharge rate of 1 cc / min to produce a nano membrane.

[0144] The nano membrane, double-sided tape, and impact protection substrate (foam tape) were sequentially injected so that the lower surface of the double-sided tape was adhered to the upper surface of the nano membrane, and the impact protection substrate was laminated thereon. Then, the sheet was passed through a mold moving at a certain pressure and speed and cut to a certain size to produce a waterproof, breathable sheet. The temperature, viscosity, electrical conductivity, and content of solvent black (content relative to 100 parts by weight of PVDF) of the added solids are as shown in Table 1 below.

[0145]

[0146] Comparative Examples 1 to 5

[0147] Polyvinylidene fluoride (PVdf), a synthetic fiber raw material, was dissolved in dimethylacetamide solvent, and then solvent black was added to prepare a spinning solution.

[0148] The above-mentioned spinning solution was electrospun using an electrospinning device at a voltage of 55 kV and a discharge rate of 1 cc / min to produce a nano membrane.

[0149] The nano membrane, double-sided tape, and impact protection material (foam tape) were sequentially injected so that the lower surface of the double-sided tape was adhered to the upper surface of the nano membrane, and the impact protection material was laminated thereon. Then, the sheet was passed through a mold moving at a certain pressure and speed and cut to a certain size to produce a waterproof, breathable sheet. The temperature, viscosity, and electrical conductivity of the added solids are as shown in Table 1 below.

[0150]

[0151] Solvent Black Raw Material Solid Content (%) Viscosity (cP) Electrical Conductivity (μS / cm) Addition Amount (parts by weight) Solvent Black Example 1 PVDF 1564 36 1.41 28 Example 2 PVDF 1564 5 3.6 0.5 28 Example 3 PVDF 1565 6 15 2.33 28 Example 4 PVDF 1566 8 42.65 3 Example 5 PVDF 1563 6 14.5 13 Example 6 PVDF 1563 5 49.5 127 Comparative Example 1 PVDF 1563 3 5.8--Comparative Example 2PVDF15675273.2528Comparative Example 3PVDF156356.70.13Comparative Example 4PVDF25215358.3128Comparative Example 5PVDF525756.9128

[0152] Experimental example: Evaluation of a nanomembrane and a waterproof, breathable sheet containing the same

[0153] The unit weight, fiber diameter, thickness, porosity, air permeability, pore size, and water pressure resistance of the nano membranes used in Examples 1 to 6 and Comparative Examples 1 to 5 were measured, and the water pressure waterproofing performance, air permeability, and sound transmission loss at room temperature, low temperature, thermal shock, high temperature, and high humidity of the waterproof and breathable sheet manufactured therefrom were measured, respectively, and are summarized and shown in Tables 2 and 3 below.

[0154]

[0155] Classification Specification (Nanomembrane) Unit weight (g / ㎡) Fiber diameter (㎛) Thickness (㎛) Porosity (%) Air permeability (㎤ / ㎠ / sec) Pore size (㎛) Water pressure (mmH₂O) Example 15.40.341577.51.70.5413,900 Example 25.50.491674.72.10.7410,700 Example 35.60.391675.71.80.6012,800 Example 45.40.431572.71.90.6811,400 Example 55.50.881575.62.30.898,600 Example 65.50.411574.61.80.6512,100Comparative example 15.51.121675.62.71.173,700Comparative example 2Film type (membrane type X)Comparative example 35.31.231574.53.11.124,300Comparative example 4Film type (membrane type X)Comparative example 5Fiber formation impossible (membrane type X)

[0156] Classification specifications (waterproof breathable sheet) Water pressure waterproofing (room temperature) Water pressure waterproofing (low temperature) Water pressure waterproofing (thermal shock) Water pressure waterproofing (high temperature and high humidity) Breathability (cc / min@1PSI) Sound transmission loss (dB) Example 15m, 130min5m, 110min5m, 110min5m, 90min561.0 Example 25m, 100min5m, 80min5m, 80min5m, 70min681.1 Example 35m, 120min5m, 100min5m, 100min5m, 90min611.3 Example 45m, 110min5m, 90min5m, 90min5m, 80min650.9 Example 55m, 80min5m, 70 min 5 m, 70 min 5 m, 60 min 721.1 Exemplary example 65 m, 120 min 5 m, 100 min 5 m, 100 min 5 m, 80 min 621.2 Comparative example 15 m, 1 min 5 m, 0 min 5 m, 0 min 5 m, 0 min 821.4 Comparative example 2 Film type (membrane type X) Comparative example 35 m, 3 min 5 m, 0 min 5 m, 0 min 5 m, 0 min 801.3 Comparative example 4 Film type (membrane type X) Comparative example 5 Fiber formation impossible (membrane type X)

[0157] Referring to Table 2 above, it can be confirmed that when 0.5 to 3 parts by weight of solvent black 28 is added according to the present invention (Examples 1 to 3), the water pressure resistance is much better than when solvent black is not added (Comparative Example 1).

[0158] In addition, it can be confirmed that the water pressure resistance is much better in the case where 1 to 5 parts by weight of solvent black 3 is added according to the present invention (Examples 4 and 5) and in the case where 1 part by weight of solvent black 27 is added than in the case where solvent black is not added (Comparative Example 1).

[0159] In addition, when 5 parts by weight of solvent black was added (Comparative Example 2), it was confirmed that it was in the form of a film rather than a membrane, and when the solid content was 25% by weight (Comparative Example 4), it was also confirmed that it was in the form of a film rather than a membrane.

[0160] In addition, when the content of solvent black 3 is 0.1 part by weight, it can be confirmed that the water pressure is significantly lower than when 1 to 5 parts by weight of solvent black 3 is added according to the present invention (Examples 4 and 5).

[0161] Additionally, when the solid content is 5 wt% (Comparative Example 5), it can be confirmed that the fiber itself is not formed.

[0162]

[0163] Meanwhile, referring to Table 3, it can be confirmed that when 0.5 to 3 parts by weight of solvent black 28 is added according to the present invention (Examples 1 to 3), the waterproofing property is significantly superior to when solvent black is not added (Comparative Example 1).

[0164] In addition, it can be confirmed that the waterproofing property is significantly superior when 1 to 5 parts by weight of solvent black 3 is added according to the present invention (Examples 4 and 5) and when 1 part by weight of solvent black 27 is added, compared to the case where solvent black is not added (Comparative Example 1).

[0165] In addition, when the content of solvent black 3 is 0.1 part by weight, it can be confirmed that the waterproofness is significantly lower than when 1 to 5 parts by weight of solvent black 3 is added according to the present invention (Examples 4 and 5).

[0166]

[0167] While the above description has been made with reference to specific examples, these are merely illustrative. Those skilled in the art will appreciate that various modifications and equivalent alternative embodiments are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

[0168] The nano membrane according to the present invention can improve waterproofness by controlling the pore size of the nano membrane by adding solvent black, and the waterproof breathable sheet of the present invention can be used in electronic devices that require both waterproofness and breathability, such as audio devices such as mobile phones, portable pads, speakers, and microphones.

Claims

1. Formed from synthetic fibers containing polyvinylidene fluoride and metal complex dyes, Nano membrane with a water pressure resistance of 5,000 to 15,000 mmH2O.

2. In paragraph 1, The above metal complex dye is a nano membrane, solvent black.

3. In paragraph 2, A nano membrane, wherein the solvent black is at least one selected from the group consisting of solvent black 3, solvent black 5, solvent black 7, solvent black 22, solvent black 27, solvent black 28, solvent black 34, solvent black 45, and solvent black 46.

4. In paragraph 1, The above synthetic fiber is a nano membrane containing 0.2 to 5 parts by weight of a metal complex dye per 100 parts by weight of polyvinylidene fluoride.

5. In paragraph 1, A nano membrane having a diameter of the above synthetic fibers of 0.1 to 1 μm.

6. In paragraph 1, The above nano membrane is a nano membrane having a pore size of 1.5㎛ or less.

7. Containing a nano membrane according to any one of claims 1 to 6, A waterproof breathable sheet having water resistance that does not leak for more than 30 minutes under a water pressure of 5 m or more at room temperature (20℃±5℃) and having an acoustic transmission loss of less than 5 dB at 1000 Hz.

8. In paragraph 7, The above waterproof breathable sheet does not leak for more than 30 minutes at a water pressure of 5 m or more under the following low temperature conditions, does not leak for more than 30 minutes at a water pressure of 5 m or more under the following high temperature conditions, and does not leak for more than 30 minutes at a water pressure of 5 m or more under the following thermal shock conditions: [Low temperature conditions] Before measuring the water leakage, expose the above waterproof breathable sheet to a temperature of -20℃ for 72 hours. [High temperature conditions] Before measuring the water leakage, the above waterproof and breathable sheet is exposed to a temperature of 50℃ and a humidity of 95% for 72 hours. [Thermal shock conditions] The cycle of exposure to -40℃ and 85℃ for 1 hour each was repeated 30 times before leakage measurement.

9. A step of preparing a spinning solution obtained by mixing polyvinylidene fluoride and a metal complex dye; and A step of obtaining a nano membrane in which synthetic fibers are integrated in the form of a nonwoven fabric including a large number of pores by electrospinning the above-mentioned spinning solution; A method for manufacturing a nano membrane having a water pressure of 5,000 to 15,000 mmH2O.

10. In paragraph 9, A method for manufacturing a nano membrane, wherein the above metal complex dye is solvent black.

11. In paragraph 9, A method for manufacturing a nano membrane, wherein the above-mentioned radiation solution contains 0.2 to 5 parts by weight of a metal complex dye per 100 parts by weight of polyvinylidene fluoride.

12. In paragraph 9, A method for manufacturing a nano membrane, wherein the electrical conductivity of the above-mentioned radiation solution is 30 to 200 μS / cm.

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