Moisture-permeable waterproof film and laminate article comprising same

Abstract

One embodiment of the present specification provides a moisture-permeable waterproof film formed of a polyolefin-based resin, wherein the moisture-permeable waterproof film has a ratio of transverse-direction (TD) tensile strength to machine-direction (MD) tensile strength of 1.1 to 5.0, and a ratio of transverse-direction (TD) tensile elongation to machine-direction (MD) tensile elongation of 0.01 to 0.7.

Description

Breathable waterproof film and laminate article containing the same

[0001] This specification relates to a breathable waterproof film and a laminate article containing the same.

[0002] Clothing, shoes, gloves, hats, etc., often include a layer possessing both breathability and waterproofness—so-called a breathable waterproof layer. This breathable waterproof layer can keep the wearer dry in humid conditions, thereby providing a comfortable wearing experience. Specifically, the breathable waterproof layer allows water vapor, such as sweat, inside the garment to pass through and be released to the outside, while preventing external moisture from penetrating into the garment. By keeping the garment waterproof from rain or snow and allowing sweat to escape, it helps regulate the wearer's body temperature and maintains comfort. With the recent increase in interest in health and leisure activities, fabrics incorporating breathable waterproof layers are being applied in various fields.

[0003] As a representative breathable waterproof fabric, a breathable waterproof film manufactured using a microporous PTFE membrane and hydrophilic polyurethane is currently used to manufacture GORE-TEX® fabric laminates. Although the pore size of the PTFE membrane is larger than a water molecule, the pores are much smaller than individual water droplets; therefore, water vapor can pass through the membrane, whereas water droplets cannot. However, fluoropolymer resins, which are the main raw material of GORE-TEX® fabric, are expensive and heavy, and regulations are being tightened as they are particularly harmful to the human body and the surrounding environment. In response to this, there have been attempts to replace PTFE membranes with non-fluoropolymer resins such as polyester; however, using non-fluoropolymer resins results in reduced breathability, moisture permeability, softness, and tactile feel compared to PTFE membranes, and causes problems such as noise generation or increase during bending and / or friction.

[0004] Accordingly, there is a need to develop a breathable waterproof film that uses a non-fluorinated resin, has excellent breathability and water permeability, produces less noise upon friction, and has a good tactile feel, thereby providing a comfortable wearing experience when applied to items such as clothing, shoes, gloves, and hats.

[0005] The details of this specification are intended to solve the problems of the aforementioned prior art, and one objective of this specification is to provide a breathable waterproof film that has excellent breathability and water permeability and breathability, while also having low noise and excellent tactile feel when friction is applied, and a laminated article containing the same.

[0006] According to one aspect, a breathable waterproof film formed from a polyolefin resin is provided, wherein the breathable waterproof film has a ratio of transverse (TD) tensile strength to longitudinal (MD) tensile strength of 1.1 to 5.0 and a ratio of transverse (TD) tensile elongation to longitudinal (MD) tensile elongation of 0.01 to 0.7.

[0007] In one embodiment, the polyolefin resin may include one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and combinations of two or more of these.

[0008] In one embodiment, the weight-average molecular weight of the polyolefin resin may be 350,000 to 450,000 g / mol.

[0009] In one embodiment, the thickness of the breathable waterproof film may be 5 to 100 μm.

[0010] In one embodiment, the air permeability (Gurley) of the moisture-permeable waterproof film may be 10 to 40 seconds / 100ml.

[0011] In one embodiment, the porosity of the breathable waterproof film may be 60 to 90 volume%.

[0012] In one embodiment, the average pore size of the breathable waterproof film may be 70 to 150 nm.

[0013] In one embodiment, the longitudinal (MD) tensile strength of the breathable waterproof film may be 100 to 1,500 kgf / cm2.

[0014] In one embodiment, the transverse (TD) tensile strength of the breathable waterproof film may be 300 to 1,700 kgf / cm2.

[0015] In one embodiment, the longitudinal (MD) tensile elongation of the breathable waterproof film may be 150% or less.

[0016] In one embodiment, the transverse (TD) tensile elongation of the breathable waterproof film may be 60% or less.

[0017] According to another aspect, a laminate article is provided comprising: the above-mentioned breathable waterproof film; and at least one layer bonded in contact with the above-mentioned breathable waterproof film.

[0018] In one embodiment, the layer may include one selected from the group consisting of a textile layer, a polymer film layer, a natural leather layer, a synthetic leather layer, a fleece layer, and a combination of two or more of these.

[0019] A breathable waterproof film according to one aspect of the present specification and a laminated article containing the same have excellent breathability, waterproofness, and breathability, while also having low noise and excellent tactile feel when applied to articles such as clothing, shoes, gloves, and hats, so they can provide a comfortable wearing experience.

[0020] The effects of one aspect of this specification are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configurations described in the detailed description or claims of this specification.

[0021] Figure 1 is an SEM image of a porous film according to an example and a comparative example of the present specification.

[0022] Figure 2 is the result of evaluating the noise characteristics of a porous film upon friction according to the examples and comparative examples of the present specification.

[0023] Hereinafter, one aspect of the present specification will be described with reference to the attached drawings. However, the details described in the present specification may be implemented in various different forms and are therefore not limited to the embodiments described herein.

[0024] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0025] Terms including ordinal numbers, such as ‘first’ or ‘second’ as used in this specification, may be used to describe various components or steps, but such components or steps should not be limited by ordinal numbers. Terms including ordinal numbers should be interpreted solely for the purpose of distinguishing one component or step from other components or steps.

[0026] When a range of numerical values ​​is described in this specification, unless a specific range is otherwise described, the value has the precision of significant figures provided according to the standard rules in chemistry for significant figures. For example, 10 includes a range of 5.0 to 14.9, and the number 10.0 includes a range of 9.50 to 10.49.

[0027] Hereinafter, an embodiment of the present specification will be described in detail with reference to the attached drawings.

[0028] breathable waterproof film

[0029] A breathable waterproof film according to one aspect of the present specification is formed of a polyolefin resin, and the ratio of transverse direction (TD) tensile strength to longitudinal direction (MD) tensile strength is 1.1 to 5.0, and the ratio of transverse direction (TD) tensile elongation to longitudinal direction (MD) tensile elongation is 0.01 to 0.7.

[0030] While conducting research to maximize the performance of a breathable waterproof film manufactured using a non-fluorinated polyolefin resin, the inventors recognized that when the ratio of the longitudinal (MD) tensile properties and transverse (TD) tensile properties of the film is appropriately controlled, the film exhibits excellent breathability, waterproofness, and breathability, while also having significantly less noise upon friction and excellent tactile properties, and thus completed the present invention.

[0031] The above breathable waterproof film has excellent breathability and water resistance, and at the same time produces little noise upon friction and has an excellent tactile feel, so it can provide a comfortable wearing experience when applied to items such as clothing, shoes, gloves, and hats.

[0032] The above polyolefin resin may include one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and combinations of two or more of these, but is not limited thereto.

[0033] The weight-average molecular weight of the above polyolefin resin may be 350,000 to 450,000 g / mol. For example, it may be 350,000 g / mol, 360,000 g / mol, 370,000 g / mol, 380,000 g / mol, 390,000 g / mol, 400,000 g / mol, 410,000 g / mol, 420,000 g / mol, 430,000 g / mol, 440,000 g / mol, 450,000 g / mol, or a range between two of these values. If the weight-average molecular weight of the polyolefin resin is below the above range, extrusion for sheet manufacturing may become difficult, and if it exceeds the above range, the tactile and noise characteristics of the film may deteriorate.

[0034] The term "weight-average molecular weight" as used in this specification refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample according to the method described in the literature (Macromolecules, Vol. 34, No. 19, pp. 6812-6820 (2001) et al.).

[0035] The above breathable waterproof film may have a ratio of transverse (TD) tensile strength to longitudinal (MD) tensile strength (TD tensile strength / MD tensile strength) of 1.1 to 5.0. For example, it may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, or a range between two of these values. If the ratio of transverse (TD) tensile strength to longitudinal (MD) tensile strength is below the above range, the breathability, tactile feel, and noise characteristics of the film upon friction may be reduced, which may result in reduced comfort when applied to items such as clothing, and if it exceeds the above range, the mechanical properties of the film may be excessively degraded, making it unsuitable for manufacturing items such as clothing.

[0036] The term "longitudinal (MD) tensile strength" as used in this specification refers to the value of stress measured by applying stress to a porous film specimen of size 20 mm x 200 mm using a tensile strength testing machine until fracture occurs in the longitudinal direction (MD).

[0037] The term “transverse (TD) tensile strength” as used in this specification refers to the value of stress measured by applying stress to a porous film specimen of size 20 mm x 200 mm using a tensile strength testing machine until fracture occurs in the transverse (TD) direction.

[0038] The above breathable waterproof film may have a ratio of transverse (TD) tensile elongation to longitudinal (MD) tensile elongation (TD tensile elongation / MD tensile elongation) of 0.01 to 0.7. For example, it may be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, or a range between two of these values. If the ratio of transverse (TD) tensile elongation to longitudinal (MD) tensile elongation exceeds the above range, the breathability, tactile feel, and noise characteristics of the film upon friction are reduced, which may result in reduced comfort when applied to items such as clothing.

[0039] The term "longitudinal (MD) tensile elongation" as used in this specification refers to the value measured by applying stress to a porous film specimen of size 20 mm x 200 mm using a tensile strength testing machine until fracture occurs in the longitudinal (MD) direction.

[0040] The term “transverse (TD) tensile elongation” as used in this specification refers to the value obtained by applying stress to a porous film specimen of size 20 mm x 200 mm using a tensile strength testing machine and measuring the ratio of the elongation of the specimen until fracture occurs in the transverse (TD) direction.

[0041] The thickness of the above breathable waterproof film may be 5 to 100 μm. For example, it may be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, or a range between two of these values. If the thickness is less than the above range, the mechanical properties of the film may be excessively degraded or the waterproofness may be reduced, and if it exceeds the above range, the softness of the film may be reduced or the noise characteristics during bending and / or friction may be reduced.

[0042] The air permeability (Gurley) of the above-mentioned breathable waterproof film may be 10 to 40 seconds / 100ml. For example, it may be 10 seconds / 100ml, 15 seconds / 100ml, 20 seconds / 100ml, 25 seconds / 100ml, 30 seconds / 100ml, 35 seconds / 100ml, 40 seconds / 100ml, or a range between two of these values. If the air permeability value exceeds the above range, the breathability of the film is reduced, and the wearing comfort may be reduced when applied to items such as clothing.

[0043] The water pressure resistance of the above breathable waterproof film, measured according to ATCC127, may be 9,000 to 20,000 mmH2O. For example, it may be 9,000 mmH2O, 10,000 mmH2O, 11,000 mmH2O, 12,000 mmH2O, 13,000 mmH2O, 14,000 mmH2O, 15,000 mmH2O, 16,000 mmH2O, 17,000 mmH2O, 18,000 mmH2O, 19,000 mmH2O, 20,000 mmH2O, or a range between two of these values. If the water pressure resistance is below the above range, the waterproofness of the film is insufficient and it may be unsuitable as a breathable waterproof film.

[0044] The moisture vapor transmission rate (MVTR) of the above moisture-permeable waterproof film, measured according to DIN EN ISO 15496, may be 5,000 to 20,000 g / m2 / 24hr. For example, 5,000 g / m2 / 24hr, 6,000 g / m2 / 24hr, 7,000 g / m2 / 24hr, 8,000 g / m2 / 24hr, 9,000 g / m2 / 24hr, 10,000 g / m2 / 24hr, 11,000 g / m2 / 24hr, 2000 g / m2 / 24hr, 13,000 g / m2 / 24hr, 14,000 g / m2 / 24hr, 15,000 g / m2 / 24hr, 16,000 g / m2 / 24hr, 17,000 g / m2 / 24hr, 18,000 g / m2 / 24hr, 19,000 g / m2 / 24hr, 20,000 It may be g / m2 / 24hr or a range between two of these values. If the moisture permeability is below the above range, the film may be unsuitable as a moisture-permeable waterproof film due to insufficient moisture permeability.

[0045] The porosity of the above-mentioned breathable waterproof film may be 60 to 90 volume%. For example, it may be 60 volume%, 65 volume%, 70 volume%, 75 volume%, 80 volume%, 85 volume%, 90 volume%, or a range between two of these values. If the porosity is below the above range, the breathability and air permeability of the film may be reduced, and if it exceeds the above range, the mechanical properties of the film, including tensile strength, may be excessively reduced.

[0046] The average pore size of the above breathable waterproof film may be 70 to 150 nm. For example, it may be 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, or a range between two of these values. If the average pore size of the breathable waterproof film is less than the above range, it may be impossible to measure the average pore size, and the breathability and air permeability may be reduced; if it exceeds the above range, the mechanical properties of the film may be excessively reduced or the waterproofness may be reduced.

[0047] As used herein, the term "average pore size" refers to a value measured under pressure conditions of 20 to 100 psi using a PMI Capillary Porometer (CFP-1500AEL) in accordance with ASTM F316-03. When measuring the average pore size, a wetting solution having a surface tension of 15 to 16 dyne / cm may be used as the wetting solution. For example, Galwick (trade name) may be used as the wetting solution, but is not limited thereto.

[0048] The longitudinal (MD) tensile strength of the above breathable waterproof film may be 100 to 1,500 kgf / cm2. For example, the longitudinal (MD) tensile strength of the above breathable waterproof film may be 100 kgf / cm2, 200 kgf / cm2, 300 kgf / cm2, 400 kgf / cm2, 500 kgf / cm2, 600 kgf / cm2, 700 kgf / cm2, 800 kgf / cm2, 900 kgf / cm2, 1,000 kgf / cm2, 1,100 kgf / cm2, 1,200 kgf / cm2, 1,300 kgf / cm2, 1,400 kgf / cm2, 1,500 kgf / cm2, or a range between two of these values. If the longitudinal (MD) tensile strength of the breathable waterproof film is below the above range, the durability of the film is insufficient and it may not be suitable for manufacturing items such as clothing, and if it exceeds the above range, the breathability, breathability, tactile properties, and noise characteristics upon friction of the film are reduced, which may result in reduced comfort when applied to items such as clothing.

[0049] The transverse direction (TD) tensile strength of the above breathable waterproof film may be 300 to 1,700 kgf / cm2. For example, the transverse direction (TD) tensile strength of the above breathable waterproof film may be 300 kgf / cm2, 400 kgf / cm2, 500 kgf / cm2, 600 kgf / cm2, 700 kgf / cm2, 800 kgf / cm2, 900 kgf / cm2, 1,000 kgf / cm2, 1,100 kgf / cm2, 1,200 kgf / cm2, 1,300 kgf / cm2, 1,400 kgf / cm2, 1,500 kgf / cm2, 1,600 kgf / cm2, 1,700 kgf / cm2, or a range between two of these values. If the transverse (TD) tensile strength of the breathable waterproof film is below the above range, the durability of the film is insufficient and it may not be suitable for manufacturing items such as clothing, and if it exceeds the above range, the breathability, breathability, tactile properties, and noise characteristics upon friction of the film are reduced, which may result in reduced comfort when applied to items such as clothing.

[0050] The longitudinal (MD) tensile elongation of the above breathable waterproof film may be 150% or less. For example, the longitudinal (MD) tensile elongation of the above breathable waterproof film may be 150% or less, 140% or less, 130% or less, 120% or less, 110% or less, 100% or less, 90% or less, 80% or less, 70% or less, or 60% or less. If the longitudinal (MD) tensile elongation of the breathable waterproof film exceeds the above range, the breathability, moisture permeability, tactile sensation, and noise characteristics upon friction of the film may be degraded, and the wearing comfort may be reduced when applied to items such as clothing.

[0051] The longitudinal (MD) tensile elongation of the above breathable waterproof film may be 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more. If the longitudinal (MD) tensile elongation of the breathable waterproof film is less than the above range, the durability of the film is insufficient and may not be suitable for manufacturing articles such as clothing.

[0052] The transverse (TD) tensile elongation of the above breathable waterproof film may be 60% or less. For example, the transverse (TD) tensile elongation of the above breathable waterproof film may be 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. If the transverse (TD) tensile elongation of the above breathable waterproof film exceeds the above range, the breathability, moisture permeability, tactile properties, and noise characteristics upon friction of the film may be degraded, and the wearing comfort may be reduced when applied to items such as clothing.

[0053] The transverse (TD) tensile elongation of the above breathable waterproof film may be 5% or more. If the transverse (TD) tensile elongation of the above breathable waterproof film is less than the above range, the durability of the film is insufficient and may not be suitable for manufacturing articles such as clothing.

[0054] The above-mentioned breathable waterproof film may be manufactured by a method comprising: (a) a step of manufacturing a sheet by extruding a composition comprising the above-mentioned polyolefin resin and a pore-forming agent; (b) a step of manufacturing a precursor film by stretching the above-mentioned sheet in the longitudinal direction (MD) and the transverse direction (TD); (c) a step of extracting the pore-forming agent from the precursor film; and (d) a step of stretching in the transverse direction (TD); but is not limited thereto.

[0055] The above-mentioned breathable waterproof film is manufactured by a method of stretching a sheet in the longitudinal direction (MD) and transverse direction (TD), extracting a pore-forming agent, and then additionally performing transverse direction (TD) stretching after extraction, thereby exhibiting excellent breathability, waterproofness, and breathability, while also having low noise and excellent tactile properties when friction occurs.

[0056] Step (a) above is a step of preparing a composition comprising a polyolefin resin and a pore-forming agent, and then extruding the composition to produce a sheet. The sheet may be produced by extruding the composition through a T-die using an extruder and passing it through a casting roll, but is not limited thereto.

[0057] The thickness of the sheet may be 500 to 1,500 μm, but is not limited thereto. For example, it may be 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1,000 μm, 1,100 μm, 1,200 μm, 1,300 μm, 1,400 μm, 1,500 μm, or a range between two of these values. If the thickness of the sheet is less than the above range, the thickness of the film may become excessively thin or breakage may occur during the stretching process, and if it exceeds the above range, the thickness of the film may become excessively thick, resulting in reduced softness or reduced noise characteristics during bending and / or friction.

[0058] The above pore-forming agent may include, but is not limited to, one selected from the group consisting of paraffin oil, paraffin wax, mineral oil, solid paraffin, soybean oil, rapeseed oil, palm oil, coconut oil, di-2-ethylhexyl phthalate, dibutyl phthalate, diisononyl phthalate, diisodecyl phthalate, bis(2-propylheptyl)phthalate, naphthene oil, and combinations of two or more of these. For example, the above pore-forming agent may be paraffin oil having a kinematic viscosity of 50 to 100 cSt at 40°C.

[0059] The weight ratio of the polyolefin resin and the pore-forming agent included in the above composition may be 20:80 to 60:40. For example, it may be 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, or a range between two of these weight ratios. If the content of the polyolefin resin included in the above composition is less than the above range, the mechanical properties of the film may be reduced, and if it exceeds the above range, the porosity of the film may be reduced.

[0060] Step (b) above is a step of manufacturing a light bulb film by first stretching the sheet manufactured in Step (a) in the longitudinal direction (MD) and the transverse direction (TD). The stretching in the longitudinal direction (MD) and the transverse direction (TD) in Step (b) above may be performed simultaneously or sequentially.

[0061] Step (b) above can be performed in a stretching machine at 100 to 150 ℃.

[0062] In step (b) above, the longitudinal (MD) stretching ratio of the sheet may be 6 to 10 times. For example, it may be 6 times, 7 times, 8 times, 9 times, 10 times, or a range between these. If the longitudinal (MD) stretching ratio is below the above range, the porosity of the film may be reduced, which may lower the breathability and moisture permeability, and if it exceeds the above range, the mechanical properties of the film may be excessively degraded.

[0063] In step (b) above, the transverse direction (TD) stretching ratio of the sheet may be 2 to 10 times. For example, it may be 2 times, 3 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, or a range between these. If the transverse direction (TD) stretching ratio is less than the above range, the porosity of the film may be reduced, and the air permeability and moisture permeability may be reduced, and if it exceeds the above range, the mechanical properties of the film may be excessively reduced.

[0064] Step (c) above is a step of extracting a pore-forming agent from the precursor film prepared in Step (b) above.

[0065] In step (c) above, the extraction of the pore-forming agent may be performed by impregnating the precursor film with a solvent selected from the group consisting of pentane, hexane, benzene, dichloromethane, carbon tetrachloride, methyl ethyl ketone, acetone, and combinations of two or more of these, but is not limited thereto.

[0066] The above step (c) may further include a step of drying after extracting the pore-forming agent from the precursor film.

[0067] Step (d) above is a step of manufacturing a porous film, which is a breathable waterproof film, by secondarily stretching the precursor film from which the pore-forming agent has been extracted and removed through Step (c) above in the transverse direction (TD).

[0068] The transverse (TD) stretching ratio of step (d) above may be 3 to 8 times. For example, it may be 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, or a range between two of these values. If the transverse (TD) stretching ratio of step (d), which is performed after the extraction of the pore-forming agent, is less than the above range, the breathability, tactile feel, and noise characteristics upon friction of the film may be degraded, and the wearing comfort may be reduced when applied to items such as clothing. If it exceeds the above range, a part of the film may tear or break during the stretching process, making manufacturing impossible, or the mechanical properties of the film may be excessively degraded, making it unsuitable for manufacturing items such as clothing.

[0069] The ratio of the transverse direction (TD) stretching ratio of step (d) to the transverse direction (TD) stretching ratio of step (b) ([transverse direction (TD) stretching ratio of step (d)] / [transverse direction (TD) stretching ratio of step (b)]) may be 1.5 to 4 times. For example, it may be 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, or a range between two of these values. If the ratio is less than the above range, the breathability, tactile properties, and noise characteristics upon friction of the film may be degraded, which may result in reduced comfort when applied to items such as clothing; if the ratio exceeds the above range, the mechanical properties of the film may be excessively degraded, making it unsuitable for manufacturing items such as clothing.

[0070] Laminated items

[0071] A laminate article according to another aspect of the present specification may comprise the above-described breathable waterproof film; and at least one layer bonded in contact with the breathable waterproof film.

[0072] The above laminated article includes a breathable waterproof film that has excellent breathability and water resistance, as well as low noise and excellent tactile feel when rubbed, and can provide a comfortable wearing experience when applied to items such as clothing, shoes, gloves, and hats.

[0073] The above layer may include one selected from the group consisting of a textile layer, a polymer film layer, a natural leather layer, a synthetic leather layer, a fleece layer, and a combination of two or more of these, but is not limited thereto.

[0074] The above laminate article may be a two-layer laminate comprising a textile layer adhered to at least one surface of the porous film. Additionally, the above laminate article may be a three-layer laminate comprising a first textile layer adhered to one surface of the porous film and a second textile layer adhered to the other surface. Furthermore, by laminating additional layers, a multilayer laminate having four, five, six, or more layers may be produced.

[0075] The textile layer may be formed from woven fabric, nonwoven fabric, knit, etc. The textile layer may be formed from natural and / or synthetic textiles, for example, cotton, wool, silk, jute, polyamide, polyester, acrylic, aramid, viscose, rayon, carbon fiber, or a combination thereof, but is not limited thereto.

[0076] The polymer film layer may be formed from, for example, polyolefin, polyester, polyamide, polyurethane, polyvinyl alcohol, polyvinyl acetate, fluoropolymer, polyvinyl halide, polyvinyl chloride, epoxy resin, silicone polymer, or a combination thereof, but is not limited thereto.

[0077] The embodiments of this specification will be described in more detail below. However, the following experimental results represent only representative results among the above embodiments, and the scope and content of this specification should not be interpreted as being narrowed or limited by the embodiments. The respective effects of various embodiments of this specification not explicitly presented below will be described in detail in the relevant sections.

[0078] Examples 1–6 and Comparative Examples 1–3

[0079] 28 parts by weight of polyethylene (PE) with a weight-average molecular weight (Mw) of 400,000 or polyethylene with a weight-average molecular weight of 440,000 (a mixture of 20% by weight of polyethylene with a weight-average molecular weight of 1,000,000 and 80% by weight of polyethylene with a weight-average molecular weight of 300,000) and 72 parts by weight of paraffin oil with a kinematic viscosity of 70 cSt at 40°C were mixed and fed into a twin-screw extruder (inner diameter 58 mm, L / D=56). Under conditions of a screw rotation speed of 40 rpm and 200°C, the mixture was extruded from the twin-screw extruder into a T-die with a width of 400 mm, and then passed through a casting roll at a temperature of 40°C to produce a base sheet with a thickness of 800 μm.

[0080] The above base sheet was stretched 6 to 10 times in the longitudinal direction (MD) in a roll stretcher at 110 ℃ and stretched 2 to 10 times in the transverse direction (TD) in a tenter stretcher at 125 ℃ to produce a precursor film. The produced precursor film was immersed in a dichloromethane leaching tank at 25 ℃ for 1 minute to extract and remove paraffin oil. After drying at 50 ℃ for 5 minutes, a porous film was produced by stretching 1 to 8 times in the transverse direction (TD) in a tenter stretcher at 134 ℃.

[0081] Experimental Example 1

[0082] The thickness, air permeability, tensile strength, and tensile elongation of the porous films prepared in the above examples and comparative examples were measured in the following manner, and the tensile strength ratio and tensile elongation ratio were calculated therefrom. Unless otherwise noted regarding temperature, measurements were taken at room temperature (25 ℃), and the results are shown in Table 1 below.

[0083] -Thickness (μm): The thickness of the porous film specimen was measured using a micro-thickness gauge.

[0084] - Air permeability (Gurley, seconds / 100ml): Using the Asahi Seiko Densometer EGO2-5 model, the time it takes for 100 ml of air to pass through a porous film specimen at a measurement pressure of 0.025 MPa was measured.

[0085] - Tensile strength (kgf / cm²) 2 Using a tensile strength tester, stress was applied to a porous film specimen with dimensions of 20 mm x 200 mm, and the applied stress was measured in the longitudinal (MD) and transverse (TD) directions until fracture occurred.

[0086] - Tensile strength ratio = TD tensile strength / MD tensile strength

[0087] - Tensile elongation (%): Stress was applied to a porous film specimen with dimensions of 20 mm x 200 mm using a tensile strength tester, and the ratio of the elongation of the specimen until fracture occurred in the longitudinal direction (MD) and transverse direction (TD) was measured.

[0088] - Tensile Elongation Ratio = TD Tensile Elongation / MD Tensile Elongation

[0089] Classification Thickness Air Permeability MD Tensile Strength TD Tensile Strength Tensile Strength Ratio MD Tensile Elongation TD Tensile Elongation Tensile Elongation Ratio Example 1 2 2 40 6 40.09 2 8.01.45 6 0.6 11.8 0.19 Example 2 3 4 32 5 5 9.01,67 8.03.00 6 4.08.8 0.14 Example 3 2 0 3 6 1,270.01,405.01.11 79.028.00.35 Example 4 2 8 19 5 42.01,388.02.5 6 75.46.9 0.09 Example 5 1 5 13 4 6 8.09 3 1.01.99 5 4.25.4 0.10 Example 62010237.01,168.04.93123.76.00.05 Comparative Example 15853,434.03,582.01.0482.969.30.84 Comparative Example 2111503,083.02,928.00.9577.597.51.26 Comparative Example 3201801,983.01,992.01.00201.5146.50.73

[0090] Referring to Table 1 above, the porous films of Examples 1 to 6, which have a high tensile strength ratio of 1.11 to 4.93 and a low tensile elongation ratio of 0.05 to 0.35, were evaluated as having excellent air permeability, exhibiting low air permeability values ​​regardless of thickness. On the other hand, the porous films of Comparative Examples 1 to 3, which have a low tensile strength ratio of less than 1.1 and a high tensile elongation ratio of greater than 0.7, were evaluated as having poor air permeability due to high air permeability values. Furthermore, the porous films of Examples 1 to 6 showed lower MD tensile strength and TD tensile strength values ​​compared to the porous films of Comparative Examples 1 to 3, and it was confirmed that the TD tensile elongation was low.

[0091] Experimental Example 2

[0092] To evaluate the water permeability and water resistance of the porous films prepared in the above examples and comparative examples, their water pressure resistance and water permeability were measured.

[0093] The water pressure resistance and water vapor permeability of the porous film were each measured at least four times using the following method, and the average of the measurements was calculated. The results are shown in Table 2 below.

[0094] - Water pressure resistance (mmH2O): The water pressure resistance of the porous film specimen was measured according to ATCC127.

[0095] - Water vapor permeability (g / m²) 2 / 24hr): The moisture vapor transmission rate (MVTR) of the porous film specimen was measured according to DIN EN ISO 15496.

[0096] Classification Water Pressure Permeability Example 1 18,167,944,8.01 Example 3 19,817,932,0.59 Example 4 10,651,859,8.73 Example 5 9,370,949,0.45 Comparative Example 1 18,581,934,1.84 Comparative Example 2 20,000,891,7.20

[0097] Referring to Table 2 above, it was confirmed that the porous film manufactured in the example exhibits a level of moisture permeability and water resistance equivalent to or slightly improved compared to the porous film of the comparative example.

[0098] Experimental Example 3

[0099] The porosity and average pore size of the porous films prepared in Example 1 and Comparative Example 2 above were measured by the following method, and the results are shown in Table 3 below.

[0100] - Porosity (volume%): According to ASTM F316-03, the porosity of the porous film specimen was measured using a PMI Capillary Porometer (CFP-1500AEL, wetting solution: Galwick).

[0101] - Average pore size (nm): According to ASTM F316-03, the average pore size of porous film specimens was measured under pressure conditions of 20 to 100 psi using a PMI Capillary Porometer (CFP-1500AEL, wetting solution: Galwick).

[0102] In addition, SEM images (10K) of the porous films prepared in Example 1 and Comparative Example 2 were taken and are shown in FIG. 1.

[0103] Classification Porosity Average Pores Size Example 179.2100~110 Comparative Example 243.4 Unmeasurable

[0104] Referring to Table 3 above, it was confirmed that the porous film prepared in Example 1 had a higher porosity than the porous film prepared in Comparative Example 2. The average pore size of the porous film prepared in Example 1 was measured to be 100–110 nm, whereas the average pore size of the porous film prepared in Comparative Example 2 could not be measured under pressure conditions of 20–100 psi. Accordingly, the pressure conditions were changed to 80–320 psi, and the pore size of the porous film prepared in Comparative Example 2 was re-measured. As a result, it was confirmed that the average pore size was 40–50 nm, which is smaller than that of the porous film prepared in Example 1.

[0105] Experimental Example 4

[0106] The noise characteristics upon friction of the porous films prepared in the above examples and comparative examples were evaluated in the following manner. The results are shown in Table 4 and Figure 2 below.

[0107] - Noise Characteristics (dB): In a space equipped with a sound barrier, porous film specimens measuring 20 cm x 30 cm were folded in half and overlapped (10 cm x 30 cm). The noise levels were measured using the TES-1350A noise measuring device while holding the specimens at 10 cm intervals and moving them up and down. The distance between the specimen and the noise measuring device was set to 10 cm, and measurements were recorded at 5-second intervals for 30 seconds. The noise level was measured five times for each specimen, and the minimum (Min), maximum (Max), and average (Ave) values ​​of each measurement were evaluated. For comparison, the baseline noise of the space where the noise measurements were performed was additionally measured.

[0108] Classification Minimum Value (Min) Maximum Value (Max) Average Value (Ave) Example 1 49.8 59.9 53.8 Example 2 44.2 56.7 51.9 Example 3 53.1 58.9 55.7 Example 4 48.8 54.9 51.5 Example 5 45.9 59.4 50.1 Comparative Example 2 61.5 66.5 63.9 Comparative Example 3 65.5 70.1 67.8 Basic Noise 37.0 39.1 38.0

[0109] Referring to Table 4 and Figure 2 above, it was confirmed that the porous film specimens prepared in Examples 1 to 5 generated less noise upon friction compared to the porous film specimens prepared in the Comparative Example. This difference in noise magnitude was perceptible even to the human ear. In addition, the noise upon friction tended to increase as the thickness of the porous film increased.

[0110] When comparing the porous film specimens of Example 3 and Comparative Example 3, which have the same thickness, it was confirmed that the porous film sample of Example 3, which has a high tensile strength ratio and a low tensile elongation ratio, showed improved noise characteristics during friction compared to the specimen of Comparative Example 3.

[0111] In addition, the porous film specimen prepared in the example was evaluated to have a superior tactile feel compared to the porous film specimen prepared in the comparative example.

[0112] The foregoing description of this specification is for illustrative purposes only, and those skilled in the art to which one aspect of this specification pertains will understand that other specific forms can be easily modified without altering the technical concept or essential features described in this specification. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0113] The scope of this specification is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of this specification.

Claims

1. A breathable waterproof film formed of a polyolefin resin, The above breathable waterproof film is, The ratio of transverse (TD) tensile strength to longitudinal (MD) tensile strength is 1.1 to 5.0, and A breathable waterproof film having a ratio of transverse (TD) tensile elongation to longitudinal (MD) tensile elongation of 0.01 to 0.

7.

2. In Paragraph 1, A breathable waterproof film comprising one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and combinations of two or more of these polyolefin resins.

3. In Paragraph 1, A breathable waterproof film having a weight-average molecular weight of 350,000 to 450,000 g / mol of the above polyolefin resin.

4. In Paragraph 1, A breathable waterproof film having a thickness of 5 to 100 μm.

5. In Paragraph 1, A breathable waterproof film having a Gurley air permeability of 10 to 40 seconds / 100ml.

6. In Paragraph 1, A breathable waterproof film having a porosity of 60 to 90 volume%.

7. In Paragraph 1, A breathable waterproof film having an average pore size of 70 to 150 nm.

8. In Paragraph 1, The longitudinal (MD) tensile strength of the above breathable waterproof film is 100–1,500 kgf / cm² 2 Phosphorus, breathable waterproof film.

9. In Paragraph 1, The transverse (TD) tensile strength of the above breathable waterproof film is 300–1,700 kgf / cm² 2 Phosphorus, breathable waterproof film.

10. In Paragraph 1, A breathable waterproof film having a longitudinal (MD) tensile elongation of 150% or less.

11. In Paragraph 1, A breathable waterproof film having a transverse (TD) tensile elongation of 60% or less.

12. The breathable waterproof film of paragraph 1; and A laminated article comprising at least one layer bonded in contact with the above-mentioned breathable waterproof film.

13. In Paragraph 12, The above layer comprises one selected from the group consisting of a textile layer, a polymer film layer, a natural leather layer, a synthetic leather layer, a fleece layer, and a combination of two or more of these, a laminated article.

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