Non-fluorine-based membrane and waterproof air-permeable sheet including same

Abstract

The present invention relates to a non-fluorine-based membrane and a waterproof air-permeable sheet including same, in which the non-fluorine-based membrane does not contain fluorine and has improved waterproofness and air permeability under room temperature, low temperature, thermal shock, and high-temperature and high-humidity conditions. One aspect of the present invention is a non-fluorine-based membrane that is formed of synthetic fibers having a diameter of 1 um or less, and has a water pressure resistance of 5,000-18,000 mmH2O and an air permeability of 1 ccs or less.

Description

Non-fluorinated membrane and waterproof breathable sheet containing the same

[0001] Cross-reference regarding related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 2024-0193918 filed on December 23, 2024, the full text of which is incorporated by reference into this specification.

[0003] The present invention relates to a non-fluorine membrane, a waterproof breathable sheet including the same, and a method for manufacturing the non-fluorine membrane.

[0004] Various electronic devices, such as mobile devices, hearing aids, communication equipment like walkie-talkies, and automotive headlamps, require breathability to maintain internal and external pressure equilibrium, while simultaneously possessing waterproof performance to prevent the penetration of water / liquids and dustproof performance to prevent the penetration of contaminants / dust. Accordingly, these electronic devices include a waterproof breathable sheet that possesses both waterproof / dustproof and breathability properties.

[0005] In particular, as electronic devices such as the aforementioned mobile devices have various added performance and functions and are used more frequently, there is a demand for not only waterproof and dustproof functions in various environments but also acoustic performance that transmits sound in a form close to the original sound without distortion.

[0006] Recently, as the demand for mobile devices in underwater environments during winter and summer increases, there is a growing need for high-specification waterproof performance in various environments.

[0007] Accordingly, there is still a demand for waterproof breathable sheets that maintain excellent waterproofness even when exposed to various environments.

[0008] The problem that the present invention aims to solve is to provide a non-fluorine membrane that does not contain fluorine and has improved waterproofness and breathability under room temperature, low temperature, thermal shock, and high temperature and high humidity conditions, and a waterproof breathable sheet containing the same.

[0009] One embodiment of the present invention is a non-fluorinated membrane formed of synthetic fibers with a diameter of 1 μm or less, having a water pressure resistance of 5,000 to 18,000 mmH2O and an air permeability of 1 ccs or less.

[0010] In the present invention, the synthetic fiber may include thermoplastic polyurethane and an inorganic salt.

[0011] In the present invention, the weight-average molecular weight of the thermoplastic polyurethane may be 100,000 to 400,000 g / mol.

[0012] In the present invention, the thermoplastic polyurethane may be formed by polymerizing p-MDI (Polymeric Methylene Diphenyl Diisocyanate), TDI (Toluene Diisocyanate), 1,4-butanediol, PEG (Polyethylene Glycol), and Polyetherdiol.

[0013] In the present invention, the polyetherdiol may be one or more selected from the group consisting of PTMEG (Polytetramethylene Ether Glycol), PPG (Polypropylene Glycol), and PTMG (Polytetramethylene Glycol), and preferably may be PTMG (Polytetramethylene Glycol).

[0014] In the present invention, the inorganic salt may include one or more selected from the group consisting of Li, Ca, Fe, K, P, Mg, Na, Rb, Cs, Sr, and Ba.

[0015] In the present invention, the content of inorganic salt in the synthetic fiber may be 200 ppm or less, and the content of halogen in the synthetic fiber may be 500 ppm or less.

[0016] In the present invention, the non-fluorinated membrane may be one in which the synthetic fibers are integrated into a nonwoven fabric form by electrospinning.

[0017] In the present invention, the electrospinning can be performed with a spinning solution having an electrical conductivity value of 10 to 50 μS / cm.

[0018] In the present invention, the non-fluorinated membrane may have an average pore size of 1 μm or less.

[0019] Another aspect of the present invention is a waterproof breathable sheet comprising the above-mentioned non-fluorine membrane and having water pressure waterproofness that does not leak for more than 30 minutes at a water pressure of 5 m or more at room temperature (20℃±5℃).

[0020] In the present invention, the waterproof breathable sheet may not leak for more than 30 minutes under a water pressure of 5 m or more under the following low temperature conditions, not leak for more than 30 minutes under a water pressure of 5 m or more under the following high temperature conditions, and not leak for more than 30 minutes under a water pressure of 5 m or more under the following thermal shock conditions.

[0021] [Low temperature conditions]

[0022] The above waterproof breathable sheet was exposed to a temperature of -20℃ for 72 hours prior to leakage measurement.

[0023] [High temperature conditions]

[0024] Prior to leakage measurement, the above waterproof breathable sheet was exposed to a temperature of 50°C and 95% humidity for 72 hours.

[0025] [Thermal Shock Conditions]

[0026] Before measuring the leak, the cycle of exposing to temperatures of -40℃ and 85℃ for 1 hour each was repeated 30 times.

[0027] In the present invention, the waterproof breathable sheet may further include an adhesive layer on one or both sides of the non-fluorinated membrane.

[0028] The non-fluorine membrane according to the present invention is manufactured by electrospinning a thermoplastic polyurethane and an inorganic salt together with a synthetic fiber spinning solution, thereby not containing fluorine and simultaneously improving water resistance under low temperature, high temperature, thermal shock, and high temperature and high humidity conditions.

[0029] FIG. 1 is a diagram schematically showing the structure of a waterproof breathable sheet according to one embodiment of the present invention.

[0030] FIG. 2 is a diagram schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0031] FIG. 3 is a diagram schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0032] FIG. 4 is a diagram schematically showing the structure of a waterproof breathable sheet according to another embodiment of the present invention.

[0033] Figure 5 is an SEM image of the non-fluorinated membranes prepared in Example 1 and Comparative Example 7.

[0034] In the following, terms designated as "upper" or "upper" may include not only those directly above in contact but also those above non-contact. Singular expressions include multiple expressions unless the context clearly indicates otherwise. Furthermore, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0035] The use of the term "for example" and similar descriptive terms may apply to both the singular and the plural. Unless there is an explicit description of the order of the steps constituting the method, these steps may be performed in a suitable order and are not necessarily limited to the described order.

[0036] As used herein, the terms “comprise,” “comprising,” “formed,” “has,” “having,” or any other variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, article, or apparatus comprising a list of elements is not necessarily limited to such elements alone and may include other elements not explicitly listed or inherent to such process, method, article, or apparatus. Furthermore, unless explicitly stated otherwise, “or” means an inclusive “or” and not an exclusive “or.”

[0037] All examples or the use of exemplary terms are merely for the purpose of describing technical ideas in detail, and unless limited by the claims, the scope is not limited by such examples or exemplary terms.

[0038] FIG. 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 non-fluorinated membrane (100) and an adhesive portion (110). At this time, the adhesive portion (110) is provided on one side of the non-fluorinated membrane (100).

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

[0041] The 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] The 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 non-fluorinated membrane (100) to ensure a strong bond between the substrate (111) and the non-fluorinated membrane (100).

[0044] The first adhesive layer (112) can be any known adhesive capable of ensuring a strong bond between the non-fluorinated membrane (100) and the substrate (111), and for example, epoxy adhesive, urethane adhesive, acrylic adhesive, thermosetting adhesive, and petroleum resin adhesive may be used.

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

[0046] The second adhesive layer (113) can be used without limitation as long as it is a known adhesive capable of ensuring a strong bond between the substrate (111) and the electronic device component, for example, epoxy adhesive, urethane adhesive, acrylic adhesive, thermosetting adhesive, or petroleum resin adhesive may be used.

[0047] The first adhesive layer (112) and the second adhesive layer (113) may contain the same or different adhesives. For example, the first adhesive layer (112) and the second adhesive layer (113) may use the same adhesive, such as an acrylic adhesive.

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

[0049] The above-mentioned material (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 a plurality of films or sheets are laminated.

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

[0051] The above-mentioned non-fluorinated membrane (100) will be described later.

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

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

[0054] Figure 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-mentioned non-fluorinated membrane (200) and a first adhesive portion (210) provided on one surface of the above-mentioned non-fluorinated membrane.

[0056] In FIG. 2, the non-fluorinated membrane (100) and the first adhesive part (110) refer to the description in FIG. 1, and the details regarding the non-fluorinated membrane (200) and the first adhesive part (210) also refer to the details of the non-fluorinated membrane (100) and the first adhesive part (110) corresponding to the description in FIG. 1.

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

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

[0059] Here, regarding the first adhesive part (310), refer to the description of the first adhesive part (110) corresponding to the description of FIG. 1.

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

[0061] The 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] 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 non-fluorinated membrane (300) to ensure a strong bond between the substrate (321) and the non-fluorinated membrane (300).

[0064] The third adhesive layer (322) can be any known adhesive capable of ensuring a strong bond between the non-fluorinated membrane (300) and the substrate (321), and for example, epoxy adhesive, urethane adhesive, acrylic adhesive, thermosetting adhesive, and 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 above-mentioned fourth adhesive layer (323) can be used without limitation as long as it is a known adhesive capable of ensuring a strong bond with the shock-absorbing layer (330), for example, epoxy adhesive, urethane adhesive, acrylic adhesive, thermosetting adhesive, or petroleum resin adhesive may be used.

[0067] The third adhesive layer (322) and the fourth adhesive layer (323) may contain 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, acrylic adhesive.

[0068] The above-mentioned substrate (321) may be used in the form of a film, a sheet, or a foam, and may be used without limitation as long as it can function as a carrier for the adhesive layer (322, 323). For example, the above-mentioned 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 above-mentioned substrate (321) may be a polyester film.

[0069] The above-mentioned material (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 a plurality of films or sheets are laminated.

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

[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] The shock-absorbing layer (330) may include polyurethane foam.

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

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

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

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

[0077] The above-mentioned non-fluorinated membrane (400) and a first adhesive portion (410) and a second adhesive portion (420) provided on both sides of the above-mentioned non-fluorinated membrane are further included, and a shock-absorbing layer (430) is further included on the second adhesive portion (420).

[0078] In FIG. 4, the non-fluorinated membrane (300), the first adhesive part (310), the second adhesive part (320), and the shock-absorbing layer (330) are described with reference to FIG. 3, and the details regarding the non-fluorinated membrane (400), the first adhesive part (410), the second adhesive part (420), and the shock-absorbing layer (430) are also described with reference to the details of the non-fluorinated membrane (300), the first adhesive part (310), the second adhesive part (320), and the shock-absorbing layer (330) corresponding to the description in FIG. 3.

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

[0080] In the following, the non-fluorinated membranes (100, 200, 300, 400) exemplified in FIGS. 1 to 4 will be described in detail.

[0081] The non-fluorinated membrane according to the present invention can be manufactured by electrospinning a spinning solution containing thermoplastic polyurethane and an inorganic salt.

[0082] The weight-average molecular weight of the thermoplastic polyurethane may be 100,000 to 400,000 g / mol, and preferably 200,000 to 300,000 g / mol. If the weight-average molecular weight of the thermoplastic polyurethane is less than 100,000 g / mol, the viscosity of the spinning solution decreases and beads may be formed, and if it exceeds 400,000 g / mol, the solubility of the polymer decreases and the viscosity of the spinning solution increases, which may significantly increase the fiber diameter.

[0083] The above thermoplastic polyurethane may be formed by polymerizing p-MDI (Polymeric Methylene Diphenyl Diisocyanate), TDI (Toluene Diisocyanate), 1,4-butanediol, PEG (Polyethylene Glycol), and Polyetherdiol, and the Polyetherdiol may be one or more selected from the group consisting of PTMEG (Polytetramethylene Ether Glycol), PPG (Polypropylene Glycol), and PTMG (Polytetramethylene Glycol), and preferably PTMG (Polytetramethylene Glycol).

[0084] Since the above thermoplastic polyurethane is formed by polymerizing 4,4'-Methylenediphenyl Diisocyanate, 1,4-butanediol, and Polyetherdiol, the diameter of the non-fluorinated membrane may be 1 μm or less, and the waterproofing performance may be improved.

[0085] In the present invention, the inorganic salt may include one or more selected from the group consisting of Li, Ca, Fe, K, P, Mg, Na, Rb, Cs, Sr, and Ba, and preferably may be LiCl or CaCl2. The content of the inorganic salt in the synthetic fiber may be 200 ppm or less, and the content of the halogen in the synthetic fiber may be 500 ppm or less.

[0086] Preferably, the content of inorganic salt in the synthetic fiber is 150 ppm or less, and the content of halogen in the synthetic fiber may be 500 ppm or less.

[0087] Specifically, when the inorganic salt contained in the synthetic fiber is LiCl, the content may be 50 ppm or less and the halogen content may be 100 ppm or less, and preferably when the inorganic salt contained in the synthetic fiber is LiCl, the content may be 20 ppm or less and the halogen content may be 80 ppm or less.

[0088] In addition, when the inorganic salt contained in the synthetic fiber is CaCl2, the content may be 150 ppm or less and the halogen content may be 500 ppm or less; preferably, when the inorganic salt contained in the synthetic fiber is CaCl2, the content may be 100 ppm or less and the halogen content may be 450 ppm or less; and more preferably, when the inorganic salt contained in the synthetic fiber is CaCl2, the content may be 30 ppm or less and the halogen content may be 150 ppm or less.

[0089] A solvent for dissolving the above thermoplastic polyurethane and inorganic salt may include dimethylacetamide, dimethylacetone, dimethyl sulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphamide, trimethylphosphate, tetramethylurea, dimethylformamide, methyl ethyl ketone, tetrahydrofuran, or a combination thereof.

[0090] The above spinning solution may contain the synthetic fiber raw material in an amount of less than 25% by weight based on solid content, preferably 5% or more and less than 25% by weight, and more preferably 10% to 20% by weight. If the amount is less than 5% by weight based on solid content, spinning is difficult, and if the amount is 25% or more, water pressure resistance, etc., may decrease and water resistance may be reduced.

[0091] The above spinning solution may have a viscosity of 400 to 2500 cP, and spinning is easy within this range.

[0092] When the viscosity of the spinning solution satisfies the above range, the manufacture of synthetic fibers by electrospinning is easy; however, if the viscosity is excessively high, not only is it difficult to control the discharge speed of the spinning solution, but a decrease in processability due to nozzle clogging is also expected, and if the viscosity is excessively low, it may be difficult to form fibers.

[0093] The electrical conductivity of the above-mentioned spinning solution may be 10 to 50 μS / cm, and preferably 10 to 40 μS / cm. By including the aforementioned inorganic salt, the electrical conductivity of the spinning solution can be controlled to the above range.

[0094] The above-mentioned non-fluorinated membrane is manufactured by electrospinning, and the control of the electrical conductivity of the spinning solution is influenced by the voltage applied during the electrospinning process, thereby affecting the diameter of the final fiber and the pore distribution and shape of the non-fluorinated membrane obtained from the fiber. By controlling the microstructure of the non-fluorinated membrane through the control of these electrospinning conditions, a breathable sheet with excellent water pressure resistance can be manufactured.

[0095] The diameter of the synthetic fiber obtained by electrospinning the above spinning solution may have a diameter of 1 μm or less, and preferably may have a diameter of 0.1 to 0.5 μm.

[0096] Synthetic fibers containing inorganic salts can be electrospun from the above spinning solution to form a nonwoven fabric containing a number of pores, thereby forming a non-fluorine membrane.

[0097] The above-mentioned non-fluorinated membrane in the form of a nonwoven fabric contains a plurality of pores, and the average pore size may be 1 μm or less, and preferably the average pore size may be 0.4 to 0.8 μm.

[0098] The synthetic fibers obtained through the above electrospinning may contain inorganic salts.

[0099] At least some of the above synthetic fibers may contain inorganic salts on their surface or within the fibers.

[0100] The non-fluorinated membrane obtained by the above-described method contains a specific amount of inorganic salt and is manufactured by electrospinning it into a nonwoven fabric form, thereby having the following physical properties.

[0101] The non-fluorinated membrane of the present invention may have a water pressure resistance of 5,000 to 18,000 mmH2O as measured according to the KS K ISO 811 measurement method, and preferably 6,000 mmH2O to 15,000 mmH2O.

[0102] In addition, the non-fluorinated membrane may have an air permeability of 1 cc or less as measured according to the ASTM D 737 measurement method, and preferably 0.1 to 0.9 cc.

[0103] The above ccs is a unit of air permeability measurement, meaning "ccs = cubic centimeters per square centimeter per second," and cm 3 / cm 2 It can be expressed as / sec.

[0104] In the present invention, the waterproof breathable sheet may further include the step of providing an adhesive portion on one or both sides of the non-fluorine membrane after manufacturing the non-fluorine membrane as described above.

[0105] The adhesive portion may be provided by applying it directly onto the non-fluorinated membrane, or by manufacturing the adhesive portion separately and then bonding it onto the non-fluorinated membrane.

[0106] For the materials and specific composition regarding the above adhesive part, refer to the contents regarding the adhesive part described in FIGS. 1 to 4.

[0107] The above waterproof breathable sheet may further include the step of providing an adhesive portion on one or both sides of a non-fluorine membrane as described above, and then providing a shock-absorbing layer on at least one of the adhesive portions.

[0108] For the materials and specific composition of the shock-absorbing layer described above, refer to the contents regarding the shock-absorbing layer described in FIGS. 1 to 4.

[0109] The above waterproof breathable sheet may have the following physical properties.

[0110] The above waterproof breathable sheet may not leak for more than 30 minutes under a water pressure of 5 m or more under the following low temperature conditions, may not leak for more than 30 minutes under a water pressure of 5 m or more under the following high temperature conditions, and may not leak for more than 30 minutes under a water pressure of 5 m or more under the following thermal shock conditions.

[0111] [Low temperature conditions]

[0112] The above waterproof breathable sheet was exposed to a temperature of -20℃ for 72 hours prior to leakage measurement.

[0113] [High temperature conditions]

[0114] Prior to leakage measurement, the above waterproof breathable sheet was exposed to a temperature of 50°C and 95% humidity for 72 hours.

[0115] [Thermal Shock Conditions]

[0116] Before measuring the leak, the cycle of exposing to temperatures of -40℃ and 85℃ for 1 hour each was repeated 30 times.

[0117] The above waterproof breathable sheet may not leak for more than 30 minutes under a water pressure of 5 m or more under low temperature conditions, not leak for more than 30 minutes under a water pressure of 5 m or more under high temperature conditions, and not leak for more than 30 minutes under a water pressure of 5 m or more under thermal shock conditions.

[0118] The above waterproof breathable sheet may not leak for more than 70 minutes under a water pressure of 5 m or more under low temperature conditions, not leak for more than 50 minutes under a water pressure of 5 m or more under high temperature conditions, and not leak for more than 60 minutes under a water pressure of 5 m or more under thermal shock conditions.

[0119] The waterproof breathable sheet according to 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 acoustic devices.

[0120] The present invention will be explained in more detail below through specific embodiments, but the present invention is not limited by the following embodiments.

[0121] The evaluation methods used in the following examples and comparative examples are as follows.

[0122]

[0123] Evaluation method

[0124] (1) Unit weight: ASTM D 3776

[0125] (2) Electrical conductivity: KS C IEC 60746-3

[0126] (3) Air permeability: Area of ​​38 cm² using the ASTM D 737 method 2 , measured under the condition of a static pressure of 125 Pa

[0127] (4) Water pressure resistance: Applying the KS K ISO 811 low-pressure method to an area of ​​100 cm² 2 Measure the pressure at the point where the first droplet forms by pressurizing to 2,000 mmH2O / min.

[0128] (5) Thickness: Thickness measured according to KS K 0506 or ISO 4593 and ISO 9073-2

[0129] (6) Acoustic transmission loss: Evaluated by acoustic transmission loss test, ASTM E-2611-09

[0130] (7) Water Pressure Resistance: Use a water pressure tester capable of applying a constant water pressure for a certain period at a depth of 0 m to 20 m as specified in KS K ISO 811. For low-temperature evaluation, evaluate after pretreatment at -20 ℃ for 72 hours; for high temperature / high humidity conditions, evaluate after pretreatment at 50 ℃ and 95% humidity for 72 hours; and for thermal shock conditions, evaluate under ambient temperature (20 ℃ ± 5 ℃) after repeating one cycle of maintaining -40 ℃ and 85 ℃ for 1 hour each for 30 cycles.

[0131] (8) Air permeability: Measures the flow rate of air passing through a circular area with a diameter of 1 mm in 1 minute under a pressure of 1 PSI using the gas permeability method of a capillary flow porosity meter.

[0132] (9) Porosity : Porosity(%) = [1 - (A / B)] x 100 = {1 - [(C / D) / B]} x 100,

[0133] (A = Density of non-fluorinated membrane, B = Density of non-fluorinated membrane polymer, C = Weight of non-fluorinated membrane, D = Volume of non-fluorinated membrane)

[0134] (10) Fiber diameter: Calculate the average value after measuring at SEM x 25,000x, including 5 random measurements such as maximum and minimum diameters.

[0135] (11) Inorganic salt content: The amount added to the spinning solution is measured (weight%)

[0136] (12) Halogen content: Measured by combustion and absorption methods using ion chromatography in accordance with BS EN 14582:2016

[0137] (13) Weight-average molecular weight (g / mol): Measured using GPC (gel permeation chromatography)

[0138] Equipment Used: Agilent 1260 Infinity

[0139] Column: μ-Styragel 10³ + 10⁴ + 10 5 Å

[0140] Mobile phase: 0.05% LiCl / DMF

[0141] Flow rate: 1.0 ml / min

[0142] Temperature: 40℃

[0143] Concentration: Standard 0.25%, Sample 0.1%

[0144] Standard Substance (Calibration): PS (Polystyrene) Molecular Weight 842,000, 193,000, 65,000, 16,200, 4,000

[0145] Injection Size: Inject 100 µl of both the standard substance and the sample solution.

[0146] (14) Viscosity: After transferring the solution to a 100 ml vial, measure using a Brookfield DV2T-LV with spindle No. 62 at 23°C.

[0147]

[0148] Examples and Comparative Examples

[0149] A spinning solution was prepared by dissolving a thermoplastic polyurethane (weight-average molecular weight of about 220,000 g / mol) formed by polymerizing p-MDI (Polymeric Methylene Diphenyl Diisocyanate), TDI (Toluene Diisocyanate), 1,4-butanediol, PEG (Polyethylene Glycol), and PTMG (Polytetramethylene Glycol) as synthetic fiber raw materials, and an inorganic salt in a dimethylacetamide / acetone mixed solvent at the concentrations shown in Table 1 below.

[0150] A non-fluorinated membrane was manufactured by electrospinning the above spinning solution using an electrospinning device under conditions of a voltage of 55 kV and a discharge rate of 1 cc / min.

[0151] The above-mentioned non-fluorine membrane, double-sided tape, and shock-protecting material were fed continuously so that the lower surface of the double-sided tape was adhered to the upper surface of the above-mentioned non-fluorine membrane, and the shock-protecting material was laminated thereon. Then, a waterproof breathable sheet was manufactured by passing it through a mold moving at a constant pressure and speed and cutting it to a certain size.

[0152]

[0153] Classification Spinning Solution Inorganic Salt Raw Material Mw (g / mol) Solid Content (%) Viscosity (cP) Electrical Conductivity (μS / cm) Type Content (ppm) Halogen Content (ppm) Example 1 TPU 20,000 151 463 12.6 Li 9 N / D Example 2 TPU 220,000 151 523 21.2 Li 155 6 Example 3 TPU 220,000 151 493 28.6 Li 207 7 Example 4 TPU 220,000 151 475 13.2 Ca 209 8 Example 5 TPU 220,000 151 482 18.7 Ca 301 41 Example 6 TPU 220,000 151 513 31.9 Ca 100 44 2 Comparative Example 1TPU50,0001523122.8Li1547Comparative Example 2TPU450,00015428323.2Li1557Comparative Example 3TPU220,00015216.6Li15-Comparative Example 4TPU220,000251524324.3Li15-Comparative Example 5TPU220,000151525363.3Li250-Comparative Example 6TPU220,00015148380.2Ca2501226Comparative Example 7TPU220,0001514481.6--N / D

[0154] N / D: 30ppm or less

[0155]

[0156] Referring to Table 1 above, Comparative Example 1 had a weight-average molecular weight of TPU that was too low, so after spinning, the membrane did not detach from the substrate (paper).

[0157] In addition, Comparative Example 3 had a solid content of 1%, so no fibrous structure was formed during spinning, and Comparative Example 4 had a solid content of 25%, which was too high, so spinning did not proceed.

[0158] In addition, Comparative Example 5 had an electrical conductivity that was too high due to the high lithium content, making it impossible to form fibers during spinning.

[0159] Meanwhile, in Examples 1 to 6, the halogen was detected at 500 ppm or less, whereas in Comparative Example 6, the halogen was 1,226 ppm, which is more than twice as high as 500 ppm.

[0160]

[0161] Evaluation Example 1: Evaluation of a non-fluorine membrane and a waterproof breathable sheet containing the same

[0162] The unit weight, fiber diameter, thickness, porosity, air permeability, pore size, and water pressure resistance of the non-fluorinated membranes used in Examples 1 to 6 and Comparative Examples 1 to 7 were measured, and the water pressure waterproofing performance, air permeability, and sound transmission loss of the waterproof breathable sheets produced therefrom were measured at room temperature, low temperature, thermal shock, and high temperature and high humidity, respectively, and summarized in Tables 2 and 3 below.

[0163]

[0164] Classification Specification (Non-fluorinated Membrane) Unit Weight (g / m²) Fiber Diameter (nm) Thickness (㎛) Porosity (%) Air Permeability (ccs) Average Pore Size (㎛) Water Pressure Resistance (mmH₂O) Example 1 10.20.33 27 72.50.80.69 9,600 Example 2 10.40.21 28 71.60.50.55 11,400 Example 3 10.10.16 27 72.80.40.51 13,800 Example 49.80.28 29 72.60.70.58 10,800 Example 59.90.31 28 73.20.60.61 10,100 Example 610.10.132871.60.30.4814,300Comparative Example 1-------Comparative Example 210.31.823581.23.42.33,200Comparative Example 3-------Comparative Example 4-------Comparative Example 5-------Comparative Example 610.20.151550.30.020.331,700Comparative Example 710.31.122861.52.71.862,100

[0165] Classification Specification (Waterproof Breathable Sheet) Water Pressure Waterproof (Ambient Temperature) Water Pressure Waterproof (Low Temperature) Water Pressure Waterproof (Thermal Shock) Water Pressure Waterproof (High Temperature High Humidity) Breathability (cc / min @ 1PSI) Sound Transmission Loss (dB) Example 15m, 90 min 5m, 90 min 5m, 90 min 5m, 80 min 512.0 Example 25m, 110 min 5m, 110 min 5m, 110 min 5m, 100 min 431.8 Example 35m, 130 min 5m, 130 min 5m, 130 min 5m, 120 min 351.9 Example 45m, 100 min 5m, 100 min 5m, 100 min 5m, 90 min 471.7 Example 55m, 100 min 5m, 100 min 5m, 100 min 5m, 80 min 491.7 Example 65m, 140 min 5m, 140 min 5m, 140 min 5m, 120 min 281.6 Comparative Example 1------Comparative Example 25m, 0 min 5m, 0 min 5m, 0 min 5m, 0 min 834.3 Comparative Example 3------Comparative Example 4------Comparative Example 5------Comparative Example 65m, 0 min 5m, 0 min 5m, 0 min 5m, 0 min 101.3 Comparative Example 75m, 0 min 5m, 0 min 5m, 0 min 5m, 0 min 811.7

[0166]

[0167] Referring to Table 3 above, it can be seen that Examples 1 to 6 have a fiber diameter of less than 0.5 mm and a water pressure resistance of 9,600 to 14,300 mmH2O, whereas Comparative Example 2, which has a weight-average molecular weight of 450,000 g / mol, has a fiber diameter of 1.8 mm or more and a very low water pressure resistance of 3,200 mmH2O.

[0168] In addition, Comparative Example 6, which has an inorganic salt content of 250 ppm, has a fiber diameter of 0.15 mm, but it can be confirmed that the water pressure resistance is very low at 1,700 mmH2O.

[0169] In addition, Comparative Example 7, which does not contain inorganic salts, can be seen to have a thick fiber diameter of 1.12 mm and a very low water pressure resistance of 2,100 mmH2O.

[0170] Referring to Table 4 above, it can be seen that Examples 1 to 6 have a water resistance of at least 90 minutes at room temperature, low temperature, thermal shock, and high temperature and high humidity. On the other hand, Comparative Example 2, with a weight-average molecular weight of 450,000 g / mol, has a very low water resistance of 0 minutes at room temperature, low temperature, thermal shock, and high temperature and high humidity, and Comparative Example 6, with an inorganic salt content of 250 ppm, also has a very low water resistance of 0 minutes at room temperature, low temperature, thermal shock, and high temperature and high humidity.

[0171] In addition, Comparative Example 7, which does not contain inorganic salts, can be seen to have very low water resistance of 0 minutes at room temperature, low temperature, thermal shock, and high temperature and high humidity.

[0172]

[0173] Evaluation Example 2: SEM analysis of non-fluorinated membranes

[0174] The surface of the non-fluorinated membrane used in Example 1 and Comparative Example 7 was photographed using a scanning electron microscope (SEM), and the results are shown in Figure 5.

[0175]

[0176] Referring to FIG. 5, it can be seen that the diameter in the case including inorganic salts according to the present invention (Example 1) is smaller than in the case not including inorganic salts (Comparative Example 7).

[0177]

[0178] Although the above description has been made with reference to examples, it is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

[0179]

[0180] The non-fluorine membrane according to the present invention is manufactured by electrospinning a thermoplastic polyurethane and an inorganic salt together with a synthetic fiber spinning solution, thereby not containing fluorine and simultaneously improving water resistance under low temperature, high temperature, thermal shock, and high temperature and high humidity conditions.

Claims

1. Formed of synthetic fibers with a diameter of 1㎛ or less, and With a water pressure resistance of 5,000~18,000 mmH2O, A non-fluorinated membrane with an air permeability of 1 ccs or less.

2. In Paragraph 1, The above synthetic fiber is a non-fluorinated membrane comprising thermoplastic polyurethane and an inorganic salt.

3. In Paragraph 2, A membrane having a weight-average molecular weight of 100,000 to 400,000 g / mol of the thermoplastic polyurethane.

4. In Paragraph 2, The above thermoplastic polyurethane is a non-fluorinated membrane formed by polymerizing p-MDI (Polymeric Methylene Diphenyl Diisocyanate), TDI (Toluene Diisocyanate), 1,4-butanediol, PEG (Polyethylene Glycol), and Polyetherdiol.

5. In Paragraph 4, A non-fluorinated membrane in which the above polyetherdiol is one or more selected from the group consisting of PTMEG (Polytetramethylene Ether Glycol), PPG (Polypropylene Glycol), and PTMG (Polytetramethylene Glycol).

6. In Paragraph 2, A non-fluorinated membrane comprising one or more inorganic salts selected from the group consisting of Li, Ca, Fe, K, P, Mg, Na, Rb, Cs, Sr, and Ba.

7. In Paragraph 2, A non-fluorinated membrane having an inorganic salt content of 200 ppm or less in the synthetic fiber and a halogen content of 500 ppm or less in the synthetic fiber.

8. In Paragraph 1, The above-mentioned non-fluorinated membrane is a non-fluorinated membrane in which the above-mentioned synthetic fibers are integrated into a non-woven fabric form by electrospinning.

9. In Paragraph 8, A non-fluorinated membrane, wherein the above electrospinning is performed with a spinning solution having an electrical conductivity value of 10 to 50 μS / cm.

10. In Paragraph 1, The above-mentioned non-fluorinated membrane is a non-fluorinated membrane having an average pore size of 1 μm or less.

11. A non-fluorinated membrane according to any one of claims 1 to 10, comprising A waterproof breathable sheet having water pressure resistance that does not leak for 30 minutes or more at a water pressure of 5 m or more at room temperature (20℃±5℃).

12. In Paragraph 11, The above waterproof breathable sheet is a waterproof breathable sheet that does not leak for more than 30 minutes under a water pressure of 5 m or more under the following low temperature conditions, does not leak for more than 30 minutes under a water pressure of 5 m or more under the following high temperature conditions, and does not leak for more than 30 minutes under a water pressure of 5 m or more under the following thermal shock conditions: [Low temperature conditions] The above waterproof breathable sheet was exposed to a temperature of -20℃ for 72 hours prior to leakage measurement. [High temperature conditions] Prior to leakage measurement, the above waterproof breathable sheet was exposed to a temperature of 50°C and 95% humidity for 72 hours. [Thermal Shock Conditions] Before measuring the leak, the cycle of exposing to temperatures of -40℃ and 85℃ for 1 hour each was repeated 30 times.

13. In Paragraph 11, The above waterproof breathable sheet further comprises an adhesive layer on one or both sides of the above non-fluorinated membrane.

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