Method for producing moisture-permeable film, method for producing laminate, and moisture-permeable film

Abstract

Provided are: a method for producing a moisture-permeable film having high moisture permeability, which has a thin thickness and is suppressed in the occurrence of coating film defects, without using a solvent; and the like. In addition, the present invention provides a method for producing a laminate and a moisture-permeable film. A method for producing a moisture-permeable film, said method comprising: a step X1 in which a moisture-curable hot-melt polyurethane resin composition is heated and melted, and a coating film having a thickness of less than 30 [mu] m is formed by continuously coating the surface of a mold-release substrate having an arithmetic average height Sa of 0.90 [mu] m or more and / or a glossiness of 25.0 or less, and a step X2 in which a moisture-curable hot-melt polyurethane resin composition is continuously coated on the surface of a mold-release substrate having an arithmetic average height Sa of 0.90 [mu] m or more and / or a gloss of 25.0 or less; the moisture-curable polyurethane hot-melt resin composition contains a urethane prepolymer obtained by reacting a polyisocyanate (B) and a polyol (A) containing polyethylene glycol and / or polyoxyethylidene polyoxypropylene glycol (a1), and the moisture-curable polyurethane hot-melt resin composition is characterized in that the moisture-curable polyurethane hot-melt resin composition forms a moisture-permeable film having a transmittance of 4000 g / m2 / 24 h or more by curing the coating film at least with moisture.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a breathable membrane that can be used in the manufacture of breathable and waterproof clothing such as sportswear, adhesive bandages, diapers, and moisture-regulating building material membranes for wall or roof applications. Background Technology

[0002] Moisture-permeable membranes, which are both permeable to water vapor (moisture permeability) and impermeable to water (waterproofness), are used to bond to breathable and waterproof fabrics and synthetic leathers (hereinafter sometimes referred to as breathable and waterproof fabrics, etc.).

[0003] Moisture-permeable membranes are typically formed by casting a solvent-based or water-based resin solution onto a release substrate and then evaporating the solvent. However, this manufacturing method requires a large amount of energy to evaporate the solvent, which has been considered a problem in recent years.

[0004] On the other hand, the method of manufacturing a moisture-permeable membrane using a hot-melt resin composition that is substantially solvent-free is effective in eliminating the problems caused by the aforementioned solvents. For example, moisture-curing polyurethane hot-melt compositions are known as such hot-melt resin compositions (see, for example, Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2007-63510 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, if a solvent-free, moisture-curing polyurethane hot-melt composition is used to manufacture a thin, breathable membrane with a thickness of less than 30 μm (especially less than 20 μm), due to the characteristics of hot melting, defects such as streaks, pits, and pinholes (hereinafter, sometimes collectively referred to as "coating defects" or "defects") are easily generated in the coating and / or the cured film of the aforementioned coating, leading to poor appearance and reduced moisture permeability. Furthermore, even if a thin, defect-free breathable membrane can be manufactured, high moisture permeability is sometimes not achieved. It should be noted that in methods for manufacturing breathable membranes using solvent-based or water-based resin solutions, the coating thickness can be relatively large during the resin solution coating stage. As the solvent and water evaporate, the film thickness becomes the desired thinness after drying, thus reducing the aforementioned problems.

[0010] The present invention was made in view of the above-mentioned actual situation, and provides a method for manufacturing a thin, highly permeable membrane that suppresses the generation of defects such as streaks, dents, and pinholes without using solvents such as water or solvents.

[0011] Methods for solving problems

[0012] The present invention includes the following embodiments.

[0013] [1] A method for manufacturing a moisture-permeable membrane includes the following steps X1 and X2, wherein step X1 is: heating and melting a moisture-curing polyurethane hot melt resin composition, and continuously coating the heated and melted moisture-curing polyurethane hot melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least a first main surface of 0.90 μm or more and / or a gloss of 25.0 or less, thereby forming a coating film with a thickness of less than 30 μm; and step X2 is: at least moisture-curing the coating film to form a moisture-permeable membrane as a cured product of the moisture-curing polyurethane hot melt resin composition.

[0014] The above-mentioned moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B).

[0015] The permeability of the above-mentioned moisture-permeable membrane is 4000 (g / m²). 2 / 24h) or more.

[0016] [2] According to the method for manufacturing the moisture-permeable membrane described in [1] above, wherein,

[0017] The aforementioned polyol (A) further comprises crystalline polyester polyol (a3).

[0018] [3] According to the method for manufacturing the moisture-permeable membrane described in [1] or [2] above, wherein,

[0019] The aforementioned polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

[0020] [4] The method for manufacturing the moisture-permeable membrane according to any one of [1] to [3] above, wherein,

[0021] The above-mentioned moisture-curing polyurethane hot melt resin composition has a melt viscosity of 100 to 10000 mPa·s at 120°C.

[0022] [5] The method for manufacturing the moisture-permeable membrane according to any one of [1] to [4] above, wherein,

[0023] The proportion of the aforementioned polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the aforementioned polyol (A) is 50% by mass or more in the total amount (100% by mass) of the aforementioned polyol (A).

[0024] [6] The method for manufacturing the moisture-permeable membrane according to any one of [1] to [5] above, wherein,

[0025] The proportion of oxyethylidene structures in the above polyol (A) is above 10 mol / kg.

[0026] [7] A method for manufacturing a laminate, wherein the laminate has a moisture-permeable membrane and an adhesive body in direct contact with one side of the moisture-permeable membrane.

[0027] The manufacturing method includes the following steps Y1 and Y2. Step Y1 involves heating and melting a moisture-curing polyurethane hot-melt resin composition, and continuously coating the heated and melted moisture-curing polyurethane hot-melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least 0.90 μm or more and / or a gloss level of 25.0 or less, forming a coating film with a thickness of less than 30 μm. Step Y2 involves bringing the surface of the adherend into contact with the surface of the coating film for bonding, and allowing the coating film to at least moisture-cur, forming a permeable film as a cured product of the moisture-curing polyurethane hot-melt resin composition.

[0028] The above-mentioned moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B).

[0029] The permeability of the above-mentioned moisture-permeable membrane is 4000 (g / m²). 2 / 24h) or more.

[0030] [8] According to the manufacturing method of the laminate described in [7] above, wherein,

[0031] The substrate to be bonded is the base fabric.

[0032] [9] According to the manufacturing method of the laminate described in [7] above, wherein,

[0033] The aforementioned bonded material is a release film or release paper.

[0034]

[10] The method for manufacturing the laminate according to any one of [7] to [9] above, wherein,

[0035] The aforementioned polyol (A) further comprises crystalline polyester polyol (a3).

[0036]

[11] The method for manufacturing the laminate according to any one of [7] to

[10] above, wherein,

[0037] The aforementioned polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

[0038]

[12] The method for manufacturing the laminate according to any one of [7] to

[11] above, wherein,

[0039] The above-mentioned moisture-curing polyurethane hot melt resin composition has a melt viscosity of 100 to 10000 mPa·s at 120°C.

[0040]

[13] The method for manufacturing the laminate according to any one of [7] to

[12] above, wherein,

[0041] The proportion of the aforementioned polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the aforementioned polyol (A) is 50% by mass or more in the total amount (100% by mass) of the aforementioned polyol (A).

[0042]

[14] The method for manufacturing the laminate according to any one of [7] to

[13] above, wherein,

[0043] The proportion of oxyethylidene structures in the above polyol (A) is above 10 mol / kg.

[0044]

[15] A moisture-permeable membrane comprising a cured product of a moisture-curing polyurethane hot-melt resin composition, wherein the moisture-curing polyurethane hot-melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B), wherein the thickness of the moisture-permeable membrane is less than 30 μm, and the permeability of the moisture-permeable membrane is 4000 (g / m²). 2 / 24h) or more.

[0045]

[16] According to the moisture-permeable membrane described in

[15] above, wherein,

[0046] The aforementioned polyol (A) further comprises crystalline polyester polyol (a3).

[0047]

[17] According to the moisture-permeable membrane described in

[15] or

[16] above, wherein,

[0048] The aforementioned polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

[0049]

[18] The moisture-permeable membrane according to any one of

[15] to

[17] above, wherein,

[0050] The proportion of the aforementioned polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the aforementioned polyol (A) is 50% by mass or more in the total amount (100% by mass) of the aforementioned polyol (A).

[0051]

[19] The moisture-permeable membrane according to any one of

[15] to

[18] above, wherein,

[0052] The proportion of oxyethylidene structures in the above polyol (A) is above 10 mol / kg.

[0053] Invention Effects

[0054] According to the present invention, a thin, highly permeable membrane with suppressed defects such as streaks, dents, and pinholes can be manufactured without the use of solvents such as water or solvents. Detailed Implementation

[0055] I. Manufacturing method of moisture-permeable membrane

[0056] The method for manufacturing the moisture-permeable membrane of the present invention includes the following steps X1 and X2. Step X1 involves heating and melting a moisture-curing polyurethane hot-melt resin composition, and continuously coating the heated and melted moisture-curing polyurethane hot-melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least a first main surface of 0.90 μm or more and / or a gloss level of 25.0 or less, thereby forming a coating film with a thickness of less than 30 μm. Step X2 involves at least moisture-curing the coating film to form a moisture-permeable membrane as a cured product of the moisture-curing polyurethane hot-melt resin composition. The moisture-curing polyurethane hot-melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The permeability of the moisture-permeable membrane is 4000 (g / m²). 2 / 24h) or above. It should be noted that sometimes the above polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) are referred to as component (a1) and described.

[0057] According to the method for manufacturing a moisture-permeable membrane of the present invention, by continuously coating a moisture-curing polyurethane hot melt resin composition without solvent, a moisture-permeable membrane that is not prone to coating defects and has high moisture permeability can be manufactured even with a thin coating film of less than 30 μm (preferably less than 20 μm) in thickness.

[0058] Furthermore, according to the method for manufacturing the breathable membrane of the present invention, by using a moisture-curing polyurethane hot melt resin composition that must contain component (a1), the coating of the moisture-curing polyurethane hot melt resin composition is made to have both moisture permeability and adhesiveness. Therefore, by curing the coating, a breathable membrane that also functions as an adhesive layer can be manufactured. Moreover, when a laminate is manufactured by bonding a substrate such as a breathable waterproof fabric to the breathable membrane, since the breathable membrane also functions as an adhesive layer, a thin laminate can be manufactured, and the interlayer adhesion between the breathable membrane and the substrate can be improved.

[0059] The following describes each step of the method for manufacturing the moisture-permeable membrane of the present invention.

[0060] 1. Process X1

[0061] In step X1, a moisture-curing polyurethane hot melt resin composition is heated and melted, and the heated and melted moisture-curing polyurethane hot melt resin composition is continuously coated on the first main surface of a release substrate having an arithmetic mean height Sa of at least the first main surface of 0.90 μm or more and / or a gloss of 25.0 or less, forming a coating film with a thickness of less than 30 μm. The moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) containing polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B).

[0062] (1) Demolding substrate

[0063] Regarding the aforementioned release substrate, at least the arithmetic mean height Sa of the first main surface is 0.90 μm or more, and / or the gloss is 25.0 or less. The first main surface of the aforementioned release substrate refers to the surface coated with the moisture-curing polyurethane hot-melt resin composition (the surface in contact with the moisture-curing polyurethane hot-melt resin composition). The first main surface of the aforementioned release substrate only needs to satisfy at least one of the arithmetic mean height Sa and gloss within a specified range; preferably, both the arithmetic mean height Sa and gloss must satisfy a specified range.

[0064] The arithmetic mean height (Sa) of the first main surface of the aforementioned release substrate is preferably 0.90 μm or more, more preferably 0.92 μm or more, even more preferably 0.95 μm or more, even more preferably 0.98 μm or more, and particularly preferably 1.0 μm or more. Furthermore, the upper limit of the arithmetic mean height (Sa) of the first main surface of the aforementioned release substrate is not particularly limited as long as a coating of a moisture-curing polyurethane hot melt resin composition can be formed and the cured coating can be peeled off; preferably 25 μm or less, more preferably 22 μm or less, and even more preferably 19 μm or less. The arithmetic mean height (Sa) is a parameter obtained by extending the arithmetic mean height Ra of a line to a surface, and is a value measured on the surface of the release substrate using a laser microscope according to ISO 25178.

[0065] Furthermore, regarding the aforementioned release substrate, the gloss of the first main surface is preferably 25.0 or less, preferably in the range of 0.1 to 25.0, more preferably in the range of 1.0 to 20.0, and even more preferably in the range of 2.0 to 17.5.

[0066] When at least one of the arithmetic mean height (Sa) and gloss of the first main surface of the aforementioned release substrate falls within the aforementioned range, the generation of coating defects can be suppressed when a thin coating film with a thickness of less than 30 μm (more preferably 20 μm or less) is formed by continuously coating a solvent-free, moisture-curing polyurethane hot melt resin composition that has been molten and heated to form a coating. Furthermore, when the moisture-permeable film, which is the cured product of the aforementioned coating film, is peeled off from the aforementioned release substrate, the moisture-permeable film becomes less prone to breakage. A moisture-permeable film with high moisture permeability and excellent mechanical strength can be manufactured.

[0067] The gloss of the aforementioned release substrate was measured using a BYK micro-gross 45XX as the measuring device, and in accordance with JIS Z 8741:1997 at a light incident angle of 60°.

[0068] Regarding the release substrate, from the viewpoint of maintaining the coating of the moisture-curing polyurethane hot melt resin composition on the first main surface, the peel force of the first main surface is greater than 0 N / inch. From the viewpoint of easily peeling the moisture-permeable film, which is the cured product of the coating, from the release substrate, the peel force of the first main surface is preferably 10 N / inch or less. Preferably, it is in the range of 0.04 N / inch to 10 N / inch, more preferably in the range of 0.2 N / inch to 8 N / inch, and even more preferably in the range of 0.45 N / inch to 6 N / inch. When the peel force of the first main surface of the release substrate is within the above range, the generation of coating defects can be suppressed when the moisture-curing polyurethane hot melt resin composition is continuously coated to form a thin coating, resulting in a good film.

[0069] Regarding the peel force of the aforementioned release substrate, a 15cm section of polyester adhesive tape (manufactured by Nitto Denko Corporation, NITTOTAPE No. 31, width 2.5cm) was cut and pre-laminated onto the release substrate using a hand roller. The following material was prepared by laminating the aforementioned polyester adhesive tape onto the aforementioned release substrate using a laminator equipped with a metal roller and a rubber roller adjusted to 40°C at a linear pressure of 0.2 MPa. The laminated polyester adhesive tape was stretched using a tensile testing machine at an environment of 23°C±2°C, RH50±5%, a peel angle of 180°, and a speed of 200 mm / min. The value at this time (N / inch) was measured and used as the peel force of the release substrate.

[0070] The structure of the aforementioned release substrate is not particularly limited. For example, it can be a single-layer release film with resin as the main component (described later), or a laminate obtained by providing a release layer with resin as the main component (described later) on at least one side of the substrate. Specifically, examples of the aforementioned laminate include release paper (paper with a release layer), release treatment cloth, water-repellent treatment cloth, resin film with release paper, and resin film with a release layer.

[0071] The resin that forms the main component of the aforementioned release film or release layer is not particularly limited, and resins commonly used in release films and release agents can be used. Examples of such resins include olefin resins such as polyethylene resin and polypropylene resin, polyester resins, fluoropolymers, and silicone resins. Among these, resins selected from olefin resins and silicone resins are preferred from the perspective of providing good release properties for polyurethane. That is, the layer constituting the first main surface (the surface in contact with the moisture-curing polyurethane hot melt resin composition) of the aforementioned release substrate preferably has olefin resin and / or silicone resin as its main components. It should be noted that the main component refers to the component with the highest content among the constituent components, and the layer constituting the first main surface (the surface in contact with the moisture-curing polyurethane hot melt resin composition) of the aforementioned release substrate is substantially composed of olefin resin and / or silicone resin.

[0072] When the aforementioned release substrate is a laminate with a release layer on one or both sides of the substrate, the substrate is not particularly limited, and examples include paper, cloth, film, or sheet. Regarding the release layer in the laminate, it can be formed by coating the substrate with resin, or it can be bonded directly to the surface of the substrate or in between other layers.

[0073] (2) Moisture-curing polyurethane hot melt resin composition

[0074] The above-mentioned moisture-curing polyurethane hot melt resin composition contains at least a urethane prepolymer as a reaction product of polyol (A) and polyisocyanate (B). The above-mentioned moisture-curing polyurethane hot melt resin composition can function as an adhesive.

[0075] The aforementioned urethane prepolymers possess "thermal fusibility." "Thermal fusibility" refers to a property arising from the molecular structure of the selected prepolymer, and is characterized by a viscous state at room temperature that makes it difficult to coat onto a solid or substrate (e.g., a release substrate), but melts upon heating, thereby enabling coating onto the substrate (e.g., a release substrate), and transforms into a solid upon cooling, exhibiting adhesive properties. In this invention, the term "thermal fusibility" is used as a general term for properties like those described above and substances possessing such properties.

[0076] -Polyol (A)-

[0077] The aforementioned polyol (A) comprises at least the aforementioned polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1). The aforementioned component (a1) possesses the excellent hydrophilicity of the oxyethylene group, thus enabling the manufacture of a breathable membrane with excellent moisture permeability.

[0078] Regarding the number average molecular weight of the above-mentioned component (a1), from the viewpoint of being able to manufacture a breathable membrane that has high moisture permeability, practical mechanical strength, and a soft feel even as a thin film, it is preferably in the range of 900 to 25,000, more preferably in the range of 1,000 to 20,000, and even more preferably in the range of 2,000 to 15,000.

[0079] In this specification, unless otherwise stated, number-average molecular weight is expressed as a value determined by gel permeation chromatography (GPC) under the conditions described below.

[0080] Measurement apparatus: High-speed GPC device (Tosoh Corporation "HLC-8220GPC")

[0081] Column: Used to connect the following columns manufactured by Tosoh Corporation in series.

[0082] “TSKgel G5000” (7.8mm I.D. × 30cm) × 1 piece

[0083] “TSKgel G4000” (7.8mm I.D. × 30cm) × 1 piece

[0084] “TSKgel G3000” (7.8mm I.D. × 30cm) × 1 piece

[0085] “TSKgel G2000” (7.8mm I.D. × 30cm) × 1 piece

[0086] Detector: RI (Differential Refractometer)

[0087] Column temperature: 40℃

[0088] Eluent: Tetrahydrofuran (THF)

[0089] Flow rate: 1.0 mL / min

[0090] Injection volume: 100 μL (0.4% by mass tetrahydrofuran solution containing the sample)

[0091] Standard sample: A calibration curve was prepared using the standard polystyrene described below.

[0092] (Standard polystyrene)

[0093] TSKgel Standard Polystyrene A-500 manufactured by Tosoh Corporation

[0094] TSKgel Standard Polystyrene A-1000 manufactured by Tosoh Corporation

[0095] TSKgel Standard Polystyrene A-2500 manufactured by Tosoh Corporation

[0096] TSKgel Standard Polystyrene A-5000 manufactured by Tosoh Corporation

[0097] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0098] TSKgel Standard Polystyrene F-2 manufactured by Tosoh Corporation

[0099] TSKgel Standard Polystyrene F-4 manufactured by Tosoh Corporation

[0100] TSKgel Standard Polystyrene F-10 manufactured by Tosoh Corporation

[0101] TSKgel Standard Polystyrene F-20 manufactured by Tosoh Corporation

[0102] TSKgel Standard Polystyrene F-40 manufactured by Tosoh Corporation

[0103] TSKgel Standard Polystyrene F-80 manufactured by Tosoh Corporation

[0104] TSKgel Standard Polystyrene F-128 manufactured by Tosoh Corporation

[0105] TSKgel Standard Polystyrene F-288 manufactured by Tosoh Corporation

[0106] TSKgel Standard Polystyrene F-550 manufactured by Tosoh Corporation

[0107] Regarding the proportion (a1) component in the polyol (A) mentioned above, from the viewpoint that the resulting moisture-permeable membrane is thin and exhibits high moisture permeability, the total amount (100% by mass) of the polyol (A) is preferably in the range of 20% to 99% by mass, more preferably in the range of 30% to 95% by mass, even more preferably in the range of 40% to 90% by mass, and particularly preferably in the range of 50% to 85% by mass. By having the proportion (a1) component in the polyol (A) mentioned above be 50% by mass or more, high moisture permeability can be exhibited even when the coating thickness is 15 μm or less, which is particularly preferable in terms of being able to manufacture moisture-permeable membranes with thinner thickness and higher moisture permeability.

[0108] In addition to component (a1) mentioned above, the aforementioned polyol (A) may also contain one or more aromatic polyester polyols (a2) as optional components. It should be noted that aromatic polyester polyol (a2) is sometimes referred to as component (a2). Furthermore, component (a2) does not include the polyester polyol (a4) described later, which is a reaction product (condensation reaction product) of a polyol obtained by adding an epoxide to bisphenol A and a polycarboxylic acid.

[0109] The aromatic polyester polyol (a2) mentioned above is not particularly limited, but from the viewpoint of improving the mechanical strength of the obtained moisture-permeable membrane, an aromatic polyester polyol having a phthalic acid backbone is preferred. Examples of aromatic polyester polyols having a phthalic acid backbone include reaction products of polyacids containing phthalic acid and compounds having two or more hydroxyl groups.

[0110] Phthalic acid, isophthalic acid, terephthalic acid, and phthalic anhydride can be used as the aforementioned phthalic acid. These can be used alone or in combination of two or more. Among these, phthalic acid and / or phthalic anhydride are preferred from the perspective of producing a breathable membrane with excellent mechanical strength and a superior hand feel.

[0111] The aforementioned phthalic acid can be used in combination with other polybasic acids as needed. Examples of these other polybasic acids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and 1,12-dodecanedicarboxylic acid. These can be used alone or in combination of two or more.

[0112] Regarding the phthalic acid content in the polyacids used as raw materials for aromatic polyester polyols (a2), from the viewpoint of easily obtaining the aforementioned effects based on the phthalic acid skeleton, the total amount (100% by mass) of the aforementioned polyacids is preferably 60% by mass or more, more preferably 80% by mass or more. It can also be 100% by mass.

[0113] Regarding compounds with two or more hydroxyl groups that serve as raw materials for aromatic polyester polyols (a2), examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptahydrate, octanediol, nonanediol, decanediol, dodecanediol, trimethylolpropane, trimethylolethane, glycerol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol, and 2-ethyl-2-butyl-1,3-propanediol. These compounds can be used alone or in combination of two or more. Among these, neopentyl glycol and diethylene glycol are preferred for further improving amorphous properties.

[0114] Regarding the number-average molecular weight of the aromatic polyester polyol (a2), from the viewpoint of manufacturing a breathable film with excellent mechanical strength and feel, a range of 900 to 5000 is preferred, and a range of 1000 to 3000 is more preferred. The number-average molecular weight of the aromatic polyester polyol (a2) was determined using the same method as that used for the number-average molecular weight of component (a1).

[0115] The proportion (amount) of aromatic polyester polyol (a2) in the above-mentioned polyol (A) can be set to a range of 0% to 60% of the total amount of the above-mentioned polyol (A) (100% by mass). From the viewpoint of obtaining a moisture-proof film with high moisture permeability and excellent mechanical strength, it is preferably a range of 5% to 55% of the above-mentioned polyol (A) in 100% by mass, more preferably a range of 8% to 50% by mass, and even more preferably a range of 10% to 40% by mass.

[0116] In addition to component (a1) mentioned above, the polyol (A) may also contain one or more crystalline polyester polyols (a3) ​​as optional components. It should be noted that the crystalline polyester polyol (a3) ​​is sometimes referred to as component (a3).

[0117] By further containing crystalline polyester polyol (a3) ​​in the moisture-curing polyurethane hot melt resin composition, the normal and water-resistant adhesive strength, mechanical strength, and moisture permeability of the resulting breathable membrane can be further improved. It should be noted that in this specification, "crystalline" refers to a property in which a peak of heat of crystallization or heat of fusion can be confirmed in DSC (differential scanning calorimetry) measurements according to JIS K7121-1987.

[0118] The above-mentioned crystalline polyester polyol (a3) ​​is obtained by the condensation reaction of low molecular weight polyol and polycarboxylic acid.

[0119] For the low molecular weight polyols used as raw materials for crystalline polyester polyols (a3), for example, ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 10-decanediol, etc. can be used. Among these, the use of neopentyl glycol is preferred in terms of imparting a soft hand feel to the moisture-permeable membrane of the present invention.

[0120] For example, succinic acid, adipic acid, octanoic acid, azelaic acid, sebacic acid, dodecyl dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydroisophthalic acid, and phthalic anhydride can be used as the raw materials for crystalline polyester polyol (a3).

[0121] The aforementioned crystalline polyester polyol (a3) ​​can be any one or more of aliphatic, alicyclic, and aromatic compounds, with crystalline aliphatic polyester polyol (a3-1) being preferred. The aforementioned crystalline aliphatic polyester polyol (a3-1) can be the reaction product of a polybasic acid and a compound having two or more hydroxyl groups. Examples of such polybasic acids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and 1,12-dodecanedicarboxylic acid. Furthermore, examples of compounds having two or more hydroxyl groups, exemplified as raw materials for the aforementioned "aromatic polyester polyol (a2)", include compounds having two or more hydroxyl groups.

[0122] From the viewpoint of improving crystallinity and being able to manufacture a breathable membrane with further superior mechanical strength, the crystalline polyester polyol (a3) ​​is preferably a crystalline aliphatic polyester polyol, which is a reaction product of one or more polyacids selected from bisaccharide, sebacic acid and 1,12-dodecanedicarboxylic acid and one or more compounds selected from ethylene glycol, butanediol, hexanediol and dodecanediol having two or more hydroxyl groups.

[0123] Regarding the number-average molecular weight of the crystalline polyester polyol (a3), from the viewpoint of manufacturing a breathable membrane with even better mechanical strength and moisture permeability, a range of 900 to 10,000 is preferred, and a range of 1,000 to 9,000 is more preferred. The number-average molecular weight of the crystalline polyester polyol (a3) ​​described above was obtained by measuring the value using the same method as that used for the number-average molecular weight of component (a1) described above.

[0124] The proportion (amount) of crystalline polyester polyol (a3) ​​in the above-mentioned polyol (A) can be set to a range of 0% to 60% of the total amount of polyol (A) (100% by mass). From the viewpoint of obtaining a moisture-proof film with a more superior feel, it is preferably a range of 1% to 55% of the polyol (A) in 100% by mass, and more preferably a range of 2% to 50% by mass.

[0125] In addition to component (a1) mentioned above, the polyol (A) may also contain one or more polyester polyols (a4) (hereinafter sometimes referred to as component (a4)) as optional components. This polyester polyol (a4) is a reaction product (condensation reaction product) of a polyol obtained by adding an epoxide to bisphenol A and a polycarboxylic acid. Component (a4) is not included in components (a1) to (a3) ​​mentioned above.

[0126] The number-average molecular weight of component (a4) is preferably in the range of 500 to 10,000, more preferably in the range of 1,000 to 4,000. By ensuring that the number-average molecular weight of component (a4) is within this range, the viscosity of the moisture-curing polyurethane hot-melt resin composition in the molten state can be reduced, thus improving continuous coatability. The number-average molecular weight of component (a4) is a value obtained by measuring it using the same method as that used for component (a1).

[0127] The glass transition temperature of component (a4) is preferably in the range of -50°C to 40°C. The glass transition temperature of component (a4) can be adjusted, for example, by adjusting the amount of epoxide addition to the bisphenol A. The glass transition temperature is the endothermic peak temperature measured using DSC (differential scanning calorimetry) under a nitrogen atmosphere from -80°C at a heating rate of 5°C / min.

[0128] The polyol obtained by adding an epoxide to bisphenol A can be manufactured, for example, by using bisphenol A as an initiator and employing a known and conventional method to add the epoxide. Among these, a polyether polyol obtained by adding an epoxide to bisphenol A is preferred.

[0129] Regarding the alkyl oxides used as raw materials for the above-mentioned component (a4), for example, ethylene oxide, propylene oxide, etc. can be used, with propylene oxide being preferred.

[0130] The epoxide used as a raw material for component (a4) is preferably added to bisphenol A in the range of 1 to 10 moles, more preferably in the range of 2 to 8 moles, and even more preferably in the range of 4 to 8 moles. Component (a4) is well compatible with other polyols, exhibits superior normal and water-resistant adhesive strength, and can be used to manufacture a breathable membrane with moisture permeability and flexibility.

[0131] The polycarboxylic acid used as the raw material for the above-mentioned component (a4) is preferably one or more compounds selected from aliphatic polycarboxylic acids, alicyclic dicarboxylic acids and aromatic polycarboxylic acids.

[0132] Regarding the aliphatic polycarboxylic acids used as raw materials for the aforementioned component (a4), examples include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These can be used individually or in combination of two or more. From the viewpoint of producing a breathable membrane with excellent initial cohesion and durability, aliphatic polycarboxylic acids with 6 to 10 carbon atoms are preferred; more specifically, compounds selected from sebacic acid, adipic acid, and dodecanedicarboxylic acid are more preferred.

[0133] Regarding the aromatic polycarboxylic acid used as the raw material for the above-mentioned component (a4), for example, phthalic acid, isophthalic acid, terephthalic acid, etc. can be used, with isophthalic acid being preferred.

[0134] Among them, the polycarboxylic acid used as the material of component (a4) above is preferably composed of one or more aliphatic polycarboxylic acids and one or more aromatic polycarboxylic acids, and preferably composed of sebacic acid and isophthalic acid.

[0135] When the polycarboxylic acid used as the material in component (a4) above is a mixture of aliphatic polycarboxylic acid and aromatic polycarboxylic acid, the ratio of aliphatic polycarboxylic acid to aromatic polycarboxylic acid ([aliphatic polycarboxylic acid / aromatic polycarboxylic acid]) is preferably 10 / 90 to 50 / 50 (equivalent ratio).

[0136] The proportion (a4) of the above-mentioned polyol (A) in the above-mentioned polyol (A) can be set to a range of 0% to 30% of the total amount of polyol (A) (100% by mass). From the viewpoint of improving compatibility with other polyols and obtaining a breathable membrane with excellent adhesive strength, moisture permeability and flexibility, it is preferably a range of 5% to 30% of the total amount of polyol (A) (100% by mass), and more preferably a range of 5% to 20% by mass.

[0137] In addition to component (a1) mentioned above, the polyol (A) may also contain one or more polyols (a5) having three hydroxyl groups (hereinafter sometimes referred to as component (a5)) as optional components. The polyol (a5) having three hydroxyl groups is a component other than components (a1) to (a4) mentioned above. By further including polyol (a5) having three hydroxyl groups in the polyol (A), the urethane prepolymer forms a cross-linked structure, which can further improve the balance between the mechanical strength and moisture permeability of the obtained moisture-permeable membrane. Component (a5) is not included in components (a1) to (a4) mentioned above.

[0138] Examples of components (a5) include glycerol, trimethylolpropane, polyoxypropylene triol, polymers of glycerol and propylene oxide, and polymers of polyoxypropylene triol and ethylene oxide, which are compounds containing oxyalkylene groups. These can be used alone or in combination of two or more. Among these, from the perspective of good compatibility with other polyol components such as component (a1) and the improvement of the moisture permeability and mechanical strength of the obtained moisture-permeable membrane, the aforementioned component (a5) is preferably a polyol containing the aforementioned oxyalkylene groups, and more preferably polyoxypropylene triol.

[0139] Regarding the number-average molecular weight of the aforementioned component (a5) (a polyol having an alkylene group and three hydroxyl groups), a range of 300 to 800 is preferred, considering its good compatibility with other polyol components such as component (a1) and the ability to manufacture a breathable membrane with further superior moisture permeability and mechanical strength. It should be noted that the number-average molecular weight of component (a5) is a value determined using the same method as that used for component (a1).

[0140] The proportion (a5) of the above-mentioned polyol (A) in the above-mentioned polyol (A) can be set to a range of 0 parts by mass to 10 parts by mass in the total amount (100% by mass) of polyol (A). From the perspective of good compatibility with the above-mentioned polyol (A) and improving the moisture permeability and mechanical strength of the obtained moisture-permeable membrane, the proportion of the above-mentioned polyol (A) in the total amount (100% by mass) is preferably in the range of 0.01% by mass to 10% by mass, more preferably in the range of 0.1% by mass to 7% by mass, and even more preferably in the range of 0.3% by mass to 5% by mass.

[0141] In addition to the component (a1) mentioned above, the aforementioned polyol (A) may also contain one or more other polyols (a6) other than those mentioned in (a1) to (a5) as optional components. Examples of the other polyols (a6) include polyester polyols, polyoxypropylene glycol, polyoxytetramethylene glycol, polyacrylic acid polyols, polycarbonate polyols, and polybutadiene polyols. These polyols may be used alone or in combination of two or more.

[0142] The proportion (content) of the oxyethylidene structure (EO backbone: -OCCO-) in the polyol (A) is preferably in the range of 5 mol / kg to 40 mol / kg, more preferably in the range of 8 mol / kg to 30 mol / kg, and even more preferably in the range of 10 mol / kg to 25 mol / kg. By ensuring the proportion of the oxyethylidene structure in the polyol (A) is within the above range, a breathable membrane can be manufactured that exhibits high moisture permeability, excellent mechanical strength, and superior hand feel even for films smaller than 30 μm. When the proportion (content) of the oxyethylidene structure (EO backbone: -OCCO-) in the polyol (A) is 10 mol / kg or more, even a breathable membrane with a thickness of 20 μm or less (including 15 μm or less) can exhibit high moisture permeability and mechanical strength, and is therefore preferred. Since the oxyethylidene structure is supplied by the above-mentioned component (a1), the content of the oxyethylidene structure can be appropriately determined by adjusting the above-mentioned component (a1).

[0143] The polyol (A) contains at least the (a1) component. Preferably, it contains the (a1) component and at least one component selected from the (a2), (a3) ​​and (a5) components. It is preferred to contain at least the (a1) and (a3) ​​components. In particular, from the perspective of being able to manufacture a moisture-permeable membrane that can exhibit good moisture permeability even for films with a thickness of 20 μm or less, it is more preferable to contain the four components (a1, (a2), (a3) ​​and (a5) components.

[0144] -Polyisocyanate (B)-

[0145] As the polyisocyanate (B), examples include aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate (e.g., 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, etc.), carbodiimide-modified diphenylmethane diisocyanate, phenylene diisocyanate, toluene diisocyanate, and naphthalene diisocyanate; and aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylphenylmethylene diisocyanate. These polyisocyanates can be used alone or in combination of two or more. Among these, aromatic polyisocyanates are preferred from the perspective of obtaining good reactivity and mechanical strength, and diphenylmethane diisocyanate is more preferred from the perspective of low vapor pressure during heating and melting.

[0146] The proportion (amount) of the above-mentioned polyisocyanate (B) in the total mass of the raw materials (solid components) constituting the urethane prepolymer is preferably in the range of 5% to 40% by mass, more preferably in the range of 10% to 30% by mass.

[0147] -Carbamate prepolymer-

[0148] The above-mentioned urethane prepolymer is obtained by reacting at least the above-mentioned polyol (A) and the above-mentioned polyisocyanate (B) as necessary raw materials.

[0149] The urethane prepolymer is a reaction product of a polyol (A) containing the above-mentioned components (a1), (a2), (a3), and (a5) and a polyisocyanate (B). When the proportion of the above-mentioned component (a1) in the polyol (A) is 50% by mass or more, it can be coated on a release substrate in a solvent-free manner with low melt viscosity, and can form a high moisture permeability coating without coating defects even when the film thickness is less than 30 μm (preferably less than 20 μm).

[0150] In addition to isocyanate groups, the aforementioned urethane prepolymers may also have olefinic unsaturated double bonds as terminal functional groups at both ends or one end. Examples of olefinic unsaturated double bonds include vinyl, allyl, and (meth)acryloyl groups. Uramate prepolymers with olefinic unsaturated double bonds at the terminal functional groups can be prepared, for example, by reacting an acrylate compound (e.g., a hydroxyl-containing (meth)acrylate) with a urethane prepolymer having two or more isocyanate groups at the terminal end of each molecule.

[0151] The softening point of the aforementioned urethane prepolymer is preferably in the range of 40 to 120°C. If the softening point of the urethane prepolymer is within this range, the continuous coatability of the moisture-curing polyurethane hot melt resin composition becomes good, and the adhesive strength is excellent. Therefore, a film-like coating can be easily formed on a release substrate, and the substrate such as a base fabric can be firmly bonded to the film. In this specification, the softening point refers to the temperature at which the urethane prepolymer begins to flow thermally and loses its cohesiveness when the temperature is gradually increased; specifically, it is the value determined by the ring and ball method (JIS K-6301).

[0152] Regarding the manufacturing method of the above-mentioned urethane prepolymer, it can be manufactured, for example, by adding each component of the above-mentioned polyol (A) to a reaction vessel containing the above-mentioned polyisocyanate (B), mixing them, and heating them, and reacting under the condition that the isocyanate groups of the above-mentioned polyisocyanate (B) are in excess relative to the hydroxyl groups of the above-mentioned polyol (A).

[0153] Regarding the equivalent ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate (B) and the hydroxyl group (OH) of the polyol (A) in the manufacture of the above-mentioned urethane prepolymer, from the viewpoint of reducing the melt viscosity of the moisture-curing hot melt resin composition after heating and melting, and of being able to manufacture a breathable membrane with excellent mechanical strength, it is preferably in the range of 1.1 to 5.0, more preferably in the range of 1.5 to 3.0.

[0154] The isocyanate group content (hereinafter referred to as "NCO%)" of the above-mentioned urethane prepolymer is preferably in the range of 1.7 to 5, more preferably in the range of 2.0 to 4.5. By having the NCO% of the urethane prepolymer within the above range, the melt viscosity of the moisture-curing hot melt resin composition can be reduced, allowing for good continuous coating and easy formation of a thin coating film free from defects such as streaks, depressions, and pinholes. Furthermore, the mechanical strength of the permeable membrane of the cured moisture-curing hot melt resin composition can be improved. The NCO% of the above-mentioned urethane prepolymer represents a value determined by potentiometric titration according to JIS K 1603-1:2007.

[0155] The NCO equivalent of the aforementioned urethane prepolymer is preferably in the range of 700 to 3000, and more preferably in the range of 800 to 2500, and even more preferably in the range of 900 to 2200, from the viewpoint that coating defects can be prevented even when forming a coating film of a moisture-curing polyurethane hot melt resin composition with a thickness of 20 μm or less. By having the NCO equivalent of the urethane prepolymer within the above range, the number-average molecular weight of the urethane prepolymer can be reduced, and the melt viscosity of the moisture-curing polyurethane hot melt resin composition after heating and melting can be decreased. Therefore, the formation of a film without coating defects becomes easier. The NCO equivalent of the aforementioned urethane prepolymer is obtained by dividing the total value of all polyol and isocyanate components of the material used as the urethane prepolymer by subtracting the polyol equivalent from the isocyanate equivalent.

[0156] Regarding the number-average molecular weight of the above-mentioned urethane prepolymer, from the viewpoint of the flowability of the moisture-curing hot melt resin composition after heating and melting, it is preferably in the range of 500 to 30,000. From the viewpoint that when the moisture-curing hot melt resin composition is coated to form a coating film with a thickness of less than 30 μm, more preferably 20 μm or less, the melt viscosity of the moisture-curing hot melt resin composition can be reduced and the generation of coating defects can be suppressed, it is more preferably in the range of 700 to 20,000, and even more preferably in the range of 1,000 to 15,000. The number-average molecular weight of the above-mentioned urethane prepolymer is a value measured using the same method as the number-average molecular weight of the component (a1) above.

[0157] The aforementioned moisture-curing polyurethane hot melt resin composition contains the aforementioned urethane prepolymer as an essential component, but may also contain other additives as needed. Examples of such other additives include, for instance, tackifiers, curing catalysts, antioxidants, tackifiers, plasticizers, stabilizers, fillers, dyes, pigments, optical brighteners, silane coupling agents, thixotropic agents, waxes, optical brighteners, thermoplastic resins, thermosetting resins, dyes, conductivity enhancers, antistatic agents, moisture permeability improvers, water repellents, oil repellents, hollow foams, compounds containing water of crystallization, flame retardants, water absorbents, hygroscopic agents, deodorizers, foam stabilizers, defoamers, mildew inhibitors, preservatives, algaecides, pigment dispersants, inactive gases, anti-blocking agents, and hydrolytic agents. These can be used alone or in combination of two or more.

[0158] Regarding the aforementioned moisture-curing polyurethane hot melt resin composition, from the viewpoint that it can be continuously coated well in a molten state and form a film-like coating, the melt viscosity at 120°C is preferably in the range of 100 to 10000 mPa·s. From the viewpoint that when the moisture-curing polyurethane hot melt resin composition is coated to form a thin coating with a thickness of less than 30 μm (more preferably 20 μm or less), the generation of coating defects can be suppressed, the melt viscosity at 120°C is more preferably in the range of 200 to 5000 mPa·s, further preferably in the range of 300 to 4000 mPa·s, and particularly preferably in the range of 400 to 3000 mPa·s. The melt viscosity of the moisture-curing polyurethane hot melt resin composition can be adjusted by the average molecular weight of the urethane prepolymer, the isocyanate group content of the urethane prepolymer, etc.

[0159] -Process X1-

[0160] In step 1 above, the moisture-curing polyurethane hot melt resin composition is applied to a release substrate without the use of a solvent. In step X1, the heating and melting temperature of the moisture-curing polyurethane hot melt resin composition is preferably in the range of 50°C to 130°C, and more preferably in the range of 80°C to 120°C.

[0161] Regarding the method of applying the above-mentioned moisture-curing polyurethane hot melt resin composition to a release substrate, there is no particular limitation as long as a film-like coating can be formed on the release substrate by continuous coating. Examples include roller coating, extrusion, gravure coating, die coating, bar coating, and doctor blade coating.

[0162] The thickness of the above-mentioned moisture-curing polyurethane hot melt resin composition coating film is less than 30 μm, and there is no particular limitation as long as it is thin and can achieve high moisture permeability. However, from the viewpoint of thinner thickness and suppressing the reduction of moisture permeability, it is more preferable to be 20 μm or less. More specifically, the coating film thickness is preferably 3 μm or more and 29 μm or less, more preferably 5 μm or more and 27 μm or less, further preferably 7 μm or more and 25 μm or less, and particularly preferably 9 μm or more and 23 μm or less.

[0163] 2. Process X2

[0164] In step X2, the coating film is at least moisture-cured to form a moisture-permeable film, which is a cured product of the moisture-curing polyurethane hot melt resin composition. In the method for manufacturing the moisture-permeable film of the present invention, the moisture-curing polyurethane hot melt resin composition coated on the release substrate is solvent-free, so the thickness of the cured coating film is the same as the thickness of the coating film in step X1.

[0165] The coating of the aforementioned moisture-curing polyurethane hot melt resin composition reacts with moisture contained in the air or moisture contained in the object in contact with the coating (e.g., a release substrate, the bonded body described in "II. Laminate" later) to form a film-like cured product, which becomes a moisture-permeable film. It is preferable that the curing reaction of the coating is fully carried out during the curing process in step X2. The curing conditions for the coating can be, for example, an ambient temperature of 20°C to 40°C, a relative humidity of 50% to 80%, and a curing time of 1 to 5 days (more typically 3 days). The curing of the coating is performed on a release substrate. The curing of the coating is generally performed while the release substrate to which the coating is formed is wound with rollers or the like, but it can also be performed without winding. In addition, the curing reaction of the coating can begin from the point in step X1 above when the moisture-curing polyurethane hot melt resin composition is applied to the release substrate.

[0166] In step X2 described above, the operation of peeling off the release substrate from the moisture-permeable membrane may be included. After the moisture-curing polyurethane hot melt resin composition is cured to form a moisture-permeable membrane, the release substrate is peeled off from the moisture-permeable membrane, thereby obtaining a single layer of the moisture-permeable membrane.

[0167] In the case where the urethane prepolymer contained in the above-mentioned moisture-curing polyurethane hot melt resin composition has olefinic unsaturated double bond groups at both ends or one end, the coating film can be further irradiated with active energy rays in step X2. This is because, in addition to curing the coating film of the moisture-curing polyurethane hot melt resin composition by moisture, the curing reaction can be further carried out by irradiation with active energy rays.

[0168] Examples of active energy rays include ultraviolet light. The amount of active energy irradiation is not particularly limited as long as it sufficiently promotes the curing reaction of the moisture-curing polyurethane hot melt resin composition coating; for example, 50 mJ / cm² is preferred. 2 ~5000mJ / cm 2 More preferably 100 mJ / cm 2 ~3000mJ / cm 2 The above-mentioned irradiation dose is based on values ​​measured using a UV detector UVR-N1 (manufactured by Nippon Battery Co., Ltd.) in the wavelength range of 300-390 nm. Examples of known lamps that irradiate active energy rays include xenon lamps, xenon-mercury lamps, metal halide lamps, high-pressure mercury lamps, and low-pressure mercury lamps.

[0169] There is no particular limitation on the timing of irradiating the coating of the above-mentioned moisture-curing polyurethane hot melt resin composition with active energy rays, but from the viewpoint of preventing a decrease in surface quality, it is preferable to irradiate it just before the release substrate with the above-mentioned coating formed is wound onto a roller or the like. In addition, the moisture curing reaction and the photocuring reaction based on the irradiation of active energy rays can be carried out simultaneously, or either one of the curing reactions can be carried out first, followed by the other curing reaction.

[0170] 3. Moisture permeable membrane

[0171] The moisture-permeable membrane obtained by the manufacturing method of the present invention has a thickness of less than 30 μm, and from the viewpoint of thinness and high moisture permeability, it is preferably 20 μm or less. More specifically, the thickness of the above-mentioned moisture-permeable membrane is preferably 3 μm or more and 29 μm or less, more preferably 5 μm or more and 27 μm or less, even more preferably 7 μm or more and 25 μm, and particularly preferably 9 μm or more and 23 μm or less.

[0172] Furthermore, the moisture-permeable membrane obtained by the manufacturing method of the present invention has a moisture permeability of 4000 g / m³ to achieve practical-level moisture permeability. 2 / 24h) or more. The moisture permeability of the membrane is determined according to the B-1 method (potassium acetate method) of JIS L1099:2012.

[0173] The moisture-permeable membrane obtained by the manufacturing method of the present invention can be in a state where it has been peeled off from the release substrate, or it can be in a state where the release substrate is attached to one side of the moisture-permeable membrane and the release substrate is peeled off during use.

[0174] Furthermore, the moisture-permeable membrane obtained by the manufacturing method of the present invention may also have a release film or release paper on the side of the main surface of the moisture-permeable membrane opposite to the bonding surface of the release substrate. The release film or release paper can be peeled off when using the moisture-permeable membrane. Regarding the manufacturing method of the moisture-permeable membrane having a release film or release paper, and the release film or release paper, since they are the same as the manufacturing method of the laminate when the bonded body is set as the release film in the description of "II. Manufacturing Method of Laminate" described later, and the release film or release paper exemplified as the bonded body, description is omitted here.

[0175] II. Method for Manufacturing Laminated Materials

[0176] The manufacturing method of the laminate of the present invention is a method for manufacturing a laminate having a moisture-permeable membrane and an adhesive body directly in contact with one side of the moisture-permeable membrane. This manufacturing method includes the following steps Y1 and Y2. Step Y1 involves: heating and melting a moisture-curing polyurethane hot-melt resin composition; continuously coating the heated and melted moisture-curing polyurethane hot-melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least the first main surface of 0.90 μm or more and / or a gloss level of 25.0 or less, thereby forming... For a coating film with a thickness of less than 30 μm, step Y2 involves: bringing the surface of the adherend into contact with the surface of the coating film for bonding; allowing the coating film to undergo at least moisture curing to form a permeable membrane, which is a cured product of the moisture-curing polyurethane hot melt resin composition. The moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The permeability of the permeable membrane is 4000 g / m². 2 / 24h) or more.

[0177] Conventional methods for manufacturing laminates with a moisture-permeable membrane involve intermittently applying an adhesive to at least one surface of the moisture-permeable membrane and then bonding a substrate, such as a moisture-permeable material, to the coated surface of the adhesive. However, this method involves forming at least three layers: the moisture-permeable membrane, the intermittent adhesive, and the substrate. This results in complex processes and difficulties in manufacturing thin laminates. Furthermore, when components other than a release film and release paper are used as the substrate to bond with the moisture-permeable membrane, the intermittent bonding of the membrane and substrate with the adhesive leads to insufficient interlayer adhesion between the membrane and the substrate, and a decrease in the overall moisture permeability of the laminate.

[0178] In contrast, according to the method for manufacturing the laminate of the present invention, a coating film is formed by continuously coating a moisture-curing polyurethane hot melt resin composition onto a specified release substrate. The cured product of the coating film serves as an adhesive layer, and the moisture-permeable membrane functions as well. Therefore, it is unnecessary to use an adhesive separately in the bonding process with the adherends, thus reducing the number of layers in the laminate. Furthermore, according to the method for manufacturing the laminate of the present invention, even without the use of solvents, the moisture-curing polyurethane hot melt resin composition can be coated with a thin layer of less than 30 μm (more preferably 20 μm or less), and defects such as depressions and pinholes can be prevented from forming on the coating film or the moisture-permeable membrane that is the cured product of the coating film. Thus, a highly moisture-permeable membrane is formed on the adherends in the form of a thin film, thereby enabling the laminate to be made thinner. Furthermore, when a component other than a release film or release paper is used as the bonded body to bond with the moisture-permeable membrane, the moisture-permeable membrane can be directly and fully bonded to the bonded body without the use of other adhesives, thereby improving the interlayer adhesion of the laminate.

[0179] 1. Process Y1

[0180] The above-mentioned process Y1 is the following process: heating and melting a moisture-curing polyurethane hot melt resin composition containing a specified urethane prepolymer, and continuously coating the heated and melted moisture-curing polyurethane hot melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least the first main surface of 0.90 μm or more and / or a gloss of 25.0 or less, to form a coating film with a thickness of less than 30 μm.

[0181] The above-described step Y1 is the same as the step X1 converted into step Y1 described in "I. Method for Manufacturing a Moisture-Permeable Membrane 1. Step X1" above, so it is omitted here. In addition, the moisture-curing polyurethane hot melt resin composition used in the above-described step Y1 is also the same as the moisture-curing polyurethane hot melt resin composition described in "I. Method for Manufacturing a Moisture-Permeable Membrane 1. Step X1" above.

[0182] 2. Process Y2

[0183] The above-mentioned step Y2 is the following step: the surface of the substrate is brought into contact with the surface of the coating film and bonded together, and the coating film is cured at least by moisture to form a moisture-permeable film, which is a cured product of the moisture-curing polyurethane hot melt resin composition. In step Y2, with the substrate bonded to the coating film of the moisture-curing polyurethane hot melt resin composition, the coating film is cured to become a moisture-permeable film, thereby enabling the manufacture of a laminate formed by directly bonding the substrate and the moisture-permeable film.

[0184] In step Y2 described above, the substrate is typically bonded to a film of a moisture-curing polyurethane hot-melt resin composition on a release substrate. In step Y2, the substrate bonded to the film of the moisture-curing polyurethane hot-melt resin composition is not particularly limited; examples include a base fabric, a resin film, and release paper. The substrate is typically bonded before the coating is fully cured.

[0185] The base fabric can be made of materials such as polyester fiber, nylon fiber, acrylonitrile fiber, polyurethane fiber, acetate fiber, rayon fiber, polylactic acid fiber, and other chemical fibers; cotton, linen, silk, wool, and their blended fibers. Alternatively, the base fabric can be nonwoven fabric, woven fabric, or braided fabric.

[0186] As for the aforementioned resin film, appropriate selection can be made according to the desired function; for example, moisture-permeable films and release films can be cited. As a moisture-permeable film, examples include resin films obtained using solvent-based and water-based polyurethane resins, thermoplastic polyurethane resins (TPU), thermoplastic polyester resins (TPE), porous polytetrafluoroethylene (PTFE), polyethylene, polypropylene, and other polyolefin resins. Furthermore, as a release film, resin films commonly used as release films, such as polyethylene films and PET films, can be cited. As a release paper, examples include release papers with a release agent coated on the surface of a paper substrate; commercially available and general-purpose products can be used.

[0187] In step Y2 above, the substrate is placed and / or pressed onto a coating of a moisture-curing polyurethane hot melt resin composition. Pressing and curing are performed using conventionally known methods, thereby allowing the coating to cure in direct contact with the substrate, forming a moisture-permeable membrane. This results in a laminate with the moisture-permeable membrane directly bonded to one side of the substrate. The curing conditions for the coating in step Y2 are the same as those described in "I. Method for Manufacturing a Moisture-Permeable Membrane 2. Step X2" above, and therefore are omitted here.

[0188] In addition, if the urethane prepolymer contained in the moisture-curing polyurethane hot melt resin composition has olefinic unsaturated double bond groups at both ends or one end, the coating film can be further irradiated with active energy rays in step Y2.

[0189] It should be noted that, in step Y2 above, except for the bonding of the coating film to the substrate, the process is the same as that described in "I. Method for Manufacturing a Moisture-Permeable Membrane 2. Step X2" above, except that step X2 is converted to step Y2. Therefore, the description is omitted here. Furthermore, the moisture-permeable membrane formed in step Y2 above has a moisture permeability of 4000 g / m³ to achieve practical-level high moisture permeability. 2 (24 hours or more) is sufficient.

[0190] In the above process Y2, the operation of peeling off the above release substrate from the above moisture-permeable membrane may also be included.

[0191] In the manufacturing method of the laminate of the present invention, when the substrate bonded to the coating film in the above-described step Y2 is a release film or release paper, the following step Y3 may also be included: after the above-described step Y2, the substrate is peeled off, an adhesive is applied to a moisture-permeable film (designated as the first moisture-permeable film), and another moisture-permeable film (designated as the second moisture-permeable film) is bonded. In the above-described step Y3, the adhesive is preferably applied intermittently.

[0192] The second permeable membrane bonded by the adhesive in the above-mentioned step Y3 can be a permeable membrane manufactured by the manufacturing method including the above-mentioned steps Y1 and Y2 (denoted as permeable membrane A), or it can be a permeable membrane manufactured by a method other than the manufacturing method including the above-mentioned steps Y1 and Y2 (denoted as permeable membrane B).

[0193] As an example of a laminate obtained by the manufacturing method of the laminate of the present invention, a laminate with the following configuration can be illustrated. It should be noted that permeable membrane A represents a permeable membrane manufactured by the manufacturing method including the above-described steps Y1 and Y2, and permeable membrane B represents a permeable membrane manufactured by a method other than the manufacturing method including the above-described steps Y1 and Y2. It should be noted that parentheses “()” indicate that the membrane may or may not be included in the configuration of the laminate.

[0194] (Mold-release substrate) / Moisture-permeable membrane A / Base fabric

[0195] (Mold-release substrate) / Moisture-permeable membrane A / Resin membrane

[0196] (Mold release substrate) / Moisture-permeable membrane A / Release film

[0197] (Mold release substrate) / Moisture-permeable membrane A / Adhesive layer / Moisture-permeable membrane A / (Mold release substrate)

[0198] (Mold release substrate) / Moisture-permeable membrane A / Adhesive layer / Moisture-permeable membrane B

[0199] The uses of the laminate obtained by the manufacturing method of the present invention are not particularly limited, for example, it can be used in sportswear, raincoats, gloves, shoes, fire suits, military uniforms, adhesive bandages, diaper films, wall materials, roofing materials, etc.

[0200] III. Moisture permeable membrane

[0201] The moisture-permeable membrane of the present invention comprises a cured product of a moisture-curing polyurethane hot-melt resin composition, wherein the moisture-curing polyurethane hot-melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The thickness of the moisture-permeable membrane is less than 30 μm, and the permeability of the moisture-permeable membrane is 4000 g / m³. 2 / 24h) or more.

[0202] The moisture-curing polyurethane hot melt resin composition constituting the moisture-permeable membrane of the present invention is the same as the moisture-curing polyurethane hot melt resin composition described in the above-mentioned "I. Method for manufacturing moisture-permeable membrane".

[0203] The thickness of the moisture-permeable membrane of the present invention is less than 30 μm, and preferably 20 μm or less from the viewpoint of achieving both thinness and high moisture permeability. More specifically, the thickness of the moisture-permeable membrane is preferably 3 μm or more and 29 μm or less, more preferably 5 μm or more and 27 μm or less, even more preferably 7 μm or more and 25 μm or less, and particularly preferably 9 μm or more and 23 μm or less. With the thickness within the above range, the moisture-permeable membrane of the present invention is a thin film, free from defects, exhibits excellent surface quality, and achieves high moisture permeability.

[0204] The moisture permeability of the moisture-permeable membrane of the present invention can be set to the same range as the preferred range of moisture permeability of the moisture-permeable membrane described in the above-mentioned "I. Method for manufacturing moisture-permeable membrane".

[0205] This invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any structure having substantially the same technical concept as described in the scope of protection of this invention, or any manner of achieving the same effect, is included within the technical scope of this invention.

[0206] [Example 1]

[0207] The abbreviations for the materials used in the preparation of urethane prepolymers are shown below.

[0208] <Polyol (A)>

[0209] <<Polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) composition>>

[0210] PEt-1: Polyoxyethylene glycol (number average molecular weight Mn: 1540, hydroxyl equivalent (gram equivalent eq.wt): 770)

[0211] PEt-2: Polyoxyethylene glycol (number average molecular weight Mn: 2000, hydroxyl equivalent (gram equivalent eq.wt): 1000)

[0212] PEt-3: Polyoxyethylene glycol (number average molecular weight Mn: 4000, hydroxyl equivalent (gram equivalent eq.wt): 1550)

[0213] PEt-4: Polyoxyethylene glycol (number average molecular weight Mn: 6000, hydroxyl equivalent (gram equivalent eq.wt): 4400)

[0214] PEt-5: Polyoxyethylene glycol (number average molecular weight Mn: 11000, hydroxyl equivalent (gram equivalent eq.wt): 5500)

[0215] <<Aromatic Polyester Polyol (a2) Ingredients>>

[0216] PEs-1: Polyester polyol (the reaction product of phthalic acid and 1,6-hexanediol, number average molecular weight Mn: 2900, hydroxyl equivalent (gram equivalent eq.wt): 1000)

[0217] ·PEs-2: Polyester polyol (reaction product of neopentyl glycol, diethylene glycol and phthalic acid, number average molecular weight: 2913, hydroxyl equivalent (gram equivalent eq.wt): 500)

[0218] <<Crystall Polyester Polyol (a3) ​​Components>>

[0219] ·PEs-3: Polyester polyol (reaction product of ethylene glycol, neopentyl glycol, 1,6-hexanediol and adipic acid, number average molecular weight Mn: 2570, hydroxyl equivalent (gram equivalent eq.wt): 2750)

[0220] ·PEs-4; Polyester polyol (reaction product of 1,6-hexanediol and sebacic acid, number average molecular weight Mn: 2523, hydroxyl equivalent (gram equivalent eq.wt): 1750)

[0221] <Polyol (a5) component with 3 hydroxyl groups>

[0222] ·PO-1: Polyoxypropylene triol (Mitsui Chemicals Co., Ltd. "T-700", number average molecular weight Mn: 700, hydroxyl equivalent (gram equivalent eq.wt): 233)

[0223] <Polyisocyanate (B)>

[0224] MDI: 4,4'-Diphenylmethane diisocyanate

[0225] [Preparation of moisture-curing polyurethane hot melt resin composition]

[0226] (Moisture-curing polyurethane hot melt resin composition (1))

[0227] In a four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser, 173.4 parts by weight of "PEt-1", 20.4 parts by weight of "PEs-2", 7.1 parts by weight of "PEs-4", and 3.1 parts by weight of "PO-1" were added and mixed. The mixture was then heated under reduced pressure at 100°C to dehydrate until the water content in the flask was below 0.05% by weight. Next, the flask was cooled to 90°C, and 61.4 parts by weight of "MDI" molten at 70°C was added. The mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content reached a constant, thus preparing a hot-melt urethane prepolymer (i) and a solvent-free moisture-curing polyurethane hot-melt resin composition (1).

[0228] (Moisture-curing polyurethane hot melt resin compositions (2)~(8))

[0229] As shown in Table 1 below, the type and amount of polyol (A), the amount of polyisocyanate (B) and compound (C) were changed, and the same procedure as in Example 1 was followed to prepare hot melt urethane prepolymers (ii) to (viii) and solvent-free moisture-curing polyurethane hot melt resin compositions (2) to (8).

[0230]

[0231] [Example 1-1]

[0232] On the surface of a release substrate A (polyolefin release paper, arithmetic mean height Sa: 1.024 μm, gloss (60° gloss value): 4.7), a solvent-free moisture-curing polyurethane hot melt resin composition (1) that has been melted at 100°C is continuously coated using a roller coater to form a coating film with a thickness of 15 μm. Next, the coating film is cured at a temperature of 23°C and a humidity of 50±5% for at least 24 hours to obtain a permeable film (1-1) as the cured product of the coating film.

[0233] [Examples 1-2~1-7]

[0234] Except for using moisture-curing polyurethane hot melt resin compositions (2) to (7) instead of moisture-curing polyurethane hot melt resin composition (1), the same procedure as in Examples 1-1 was followed to obtain a moisture-permeable membrane.

[0235] [Comparative Example 1-1]

[0236] Except that a moisture-curing polyurethane hot melt resin composition (8) was used instead of a moisture-curing polyurethane hot melt resin composition (1), the same procedure as in Examples 1-1 was followed to obtain a moisture-permeable membrane.

[0237] [Example 2-1]

[0238] On the surface of a release substrate B (polyolefin release paper, arithmetic mean height Sa: 1.103 μm, gloss (60° gloss value): 14.5), a solvent-free moisture-curing polyurethane hot melt resin composition (1) that has been melted at 100°C is continuously coated using a roller coater to form a coating film with a thickness of 15 μm. Next, the coating film is cured at a temperature of 23°C and a humidity of 50±5% for at least 24 hours to obtain a permeable film (2-1) as the cured product of the coating film.

[0239] [Examples 2-2~2-7]

[0240] Except for using moisture-curing polyurethane hot melt resin compositions (2) to (7) instead of moisture-curing polyurethane hot melt resin composition (1), the same procedure as in Example 2-1 was followed to obtain a moisture-permeable membrane.

[0241] [Comparative Example 2-1]

[0242] Except that a moisture-curing polyurethane hot melt resin composition (8) was used instead of a moisture-curing polyurethane hot melt resin composition (1), the same procedure as in Example 2-1 was followed to obtain a moisture-permeable membrane.

[0243] [Comparative Example 3-1]

[0244] On the surface of a release substrate C (silicone release paper, arithmetic mean height Sa: 0.898 μm, gloss (60° gloss value): 26.3), a solvent-free moisture-curing polyurethane hot melt resin composition (1) that has been melted at 100°C is continuously coated using a roller coater to form a coating film with a thickness of 15 μm. Next, the coating film is cured at a temperature of 23°C and a humidity of 50±5% for at least 24 hours to obtain a permeable film (3-1) as the cured product of the coating film.

[0245] [Comparative Examples 3-2 to 3-8]

[0246] Except for using moisture-curing polyurethane hot melt resin compositions (2) to (8) instead of moisture-curing polyurethane hot melt resin composition (1), the same procedure as in Comparative Example 3-1 was followed to obtain a moisture-permeable membrane.

[0247] 〔evaluate〕

[0248] <Are there any coating defects?>

[0249] In the examples and comparative examples, the appearance of the hot-melted moisture-curing polyurethane hot melt resin composition applied to the entire surface of the release substrate was visually evaluated and determined based on the following criteria.

[0250] 〇: No defects such as stripes, dents, or pinholes.

[0251] ×: Defects such as stripes, dents, and pinholes are present.

[0252] <Intensity>

[0253] The breathable membranes manufactured in the examples and comparative examples were cut into strips with a width of 5 mm and a length of 50 mm. Tensile tests were performed using a precision universal testing machine (AUTOGRAPH "AG-NX" manufactured by Shimadzu Corporation) at an environment of 40 mm chuck spacing, 10 mm / s tensile speed, 23°C temperature, and 50 ± 5% humidity. The stress at 100% tension was measured, and the mechanical strength of the breathable membrane was determined based on the following criteria.

[0254] 〇:8MPa or less

[0255] ×: Exceeding 8MPa

[0256] <Feel (Softness)>

[0257] The breathable membranes manufactured in the examples and comparative examples were bent by hand and evaluated on a scale of 5. In practical application, a scale of 3 or lower is preferred.

[0258] 1: Very soft

[0259] 2: Soft

[0260] 3: Slightly soft

[0261] 4: Slightly hard

[0262] 5: Hard

[0263] <Moisture permeability>

[0264] The moisture permeability of the permeable membranes manufactured in the examples and comparative examples was determined according to JIS L1099 (A-1: calcium chloride method). It should be noted that the moisture permeability of the permeable membranes obtained in Comparative Examples 3-1 to 3-8 was abnormally high (exceeding 10000 g / m³) due to coating defects. 2 ( / 24h), judged as "unable to be measured".

[0265] The evaluation results are shown in the table below.

[0266]

[0267]

[0268]

Claims

1. A method for manufacturing a moisture-permeable membrane, comprising the following steps X1 and X2, Step X1 involves heating and melting a moisture-curing polyurethane hot-melt resin composition, and continuously coating the molten moisture-curing polyurethane hot-melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least the first main surface of 0.90 μm or more and / or a gloss level of 25.0 or less, to form a coating film with a thickness of less than 30 μm. Step X2 involves: subjecting the coating film to at least moisture curing to form a permeable film, which is a cured product of the moisture-curing polyurethane hot melt resin composition. The moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The permeability of the moisture-permeable membrane is 4000 g / m. 2 / More than 24h.

2. The method for manufacturing the moisture-permeable membrane according to claim 1, wherein, The polyol (A) further comprises a crystalline polyester polyol (a3).

3. The method for manufacturing the moisture-permeable membrane according to claim 1, wherein, The polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

4. The method for manufacturing the moisture-permeable membrane according to claim 1, wherein, The moisture-curing polyurethane hot melt resin composition has a melt viscosity in the range of 100 mPa·s to 10000 mPa·s at 120°C.

5. The method for manufacturing a moisture-permeable membrane according to claim 1, wherein, The proportion of the polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the polyol (A) is more than 50% by mass in the total amount of the polyol (A), i.e., 100% by mass.

6. The method for manufacturing the moisture-permeable membrane according to claim 1, wherein, The proportion of oxyethylidene structures in the polyol (A) is 10 mol / kg or more.

7. A method for manufacturing a laminate, the laminate having a moisture-permeable membrane and an adhesive body directly in contact with one side of the moisture-permeable membrane. The manufacturing method comprises the following steps Y1 and Y2. The process Y1 involves heating and melting a moisture-curing polyurethane hot-melt resin composition, and continuously coating the heated and melted moisture-curing polyurethane hot-melt resin composition onto the first main surface of a release substrate having an arithmetic mean height Sa of at least the first main surface of 0.90 μm or more and / or a gloss level of 25.0 or less, to form a coating film with a thickness of less than 30 μm. Step Y2 involves: bringing the surface of the substrate into contact with the surface of the coating to adhere them, and allowing the coating to cure at least with moisture to form a permeable film, which is the cured product of the moisture-curing polyurethane hot melt resin composition. The moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The permeability of the moisture-permeable membrane is 4000 g / m. 2 / More than 24h.

8. The method for manufacturing a laminate according to claim 7, wherein, The substrate to be bonded is a base fabric.

9. The method for manufacturing a laminate according to claim 7, wherein, The bonded material is a release film or release paper.

10. The method for manufacturing a laminate according to claim 7, wherein, The polyol (A) further comprises a crystalline polyester polyol (a3).

11. The method for manufacturing a laminate according to claim 7, wherein, The polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

12. The method for manufacturing a laminate according to claim 7, wherein, The moisture-curing polyurethane hot melt resin composition has a melt viscosity in the range of 100 mPa·s to 10000 mPa·s at 120°C.

13. The method for manufacturing a laminate according to claim 7, wherein, The proportion of the polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the polyol (A) is more than 50% by mass in the total amount of the polyol (A), i.e., 100% by mass.

14. The method for manufacturing a laminate according to claim 7, wherein, The proportion of oxyethylidene structures in the polyol (A) is 10 mol / kg or more.

15. A moisture-permeable membrane comprising a cured product of a moisture-curing polyurethane hot-melt resin composition, said moisture-curing polyurethane hot-melt resin composition containing a urethane prepolymer obtained by reacting a polyol (A) comprising polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) with a polyisocyanate (B). The thickness of the moisture-permeable membrane is less than 30 μm, and the permeability of the moisture-permeable membrane is 4000 g / m. 2 / More than 24h.

16. The moisture-permeable membrane according to claim 15, wherein, The polyol (A) further comprises a crystalline polyester polyol (a3).

17. The moisture-permeable membrane according to claim 15, wherein, The polyol (A) further comprises a polyol (a5) having three hydroxyl groups.

18. The moisture-permeable membrane according to claim 15, wherein, The proportion of the polyethylene glycol and / or polyoxyethylene polyoxypropylene glycol (a1) in the polyol (A) is more than 50% by mass in the total amount of the polyol (A), i.e., 100% by mass.

19. The moisture-permeable membrane according to claim 15, wherein, The proportion of oxyethylidene structures in the polyol (A) is 10 mol / kg or more.

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