WO2024142553A1 - Polyurethane resin, moisture permeable film, and moisture permeable waterproof fabric - Google Patents

Abstract

Provided is a polyurethane resin capable of producing a moisture permeable film which is excellent in moisture permeability and is also excellent in washing resistance, alcohol resistance, recoating suitability, heat resistance, light resistance, and flexibility. This polyurethane resin is a reaction product of (i) a polyol component, (ii) a chain extender, and (iii) a polyisocyanate component. The polyol component (i) includes (i-1) polyethylene glycol and (i-2) polyether polyol. The chain extender (ii) includes (ii-1) two or more linear alkanediols having 2-4 carbon atoms. The polyisocyanate component (iii) includes (iii-1) an aromatic diisocyanate and (iii-2) an aliphatic diisocyanate. Requirement (1) is satisfied.　Requirement (1): the chain extender (ii) further includes (ii-3) a triol.

Description

Polyurethane resin, moisture-permeable film, and moisture-permeable waterproof fabric

The present invention relates to polyurethane resins, moisture-permeable films, and moisture-permeable, waterproof fabrics.

　Traditionally, microporous films made of fluororesin or polyurethane resin, nonporous films made of hydrophilic resin, etc. have been used as moisture-permeable materials for constructing fabrics that exhibit moisture permeability and waterproofness (hereinafter also referred to as "moisture-permeable waterproof fabrics"). In the case of microporous films, moisture permeability can easily decrease due to clogging with sweat or dirt. On the other hand, in the case of nonporous films made of hydrophilic resins, moisture permeability does not decrease due to clogging. For example, polyurethane resins containing hydrophilic segments are used as hydrophilic resins that constitute nonporous films.

The moisture-permeable waterproof fabric has a three-layer structure in which, for example, a moisture-permeable surface layer, an adhesive layer, and a base fabric (fabric) are laminated. A nonporous moisture-permeable film made of a hydrophilic polyurethane resin is used as the material that constitutes the surface layer. As a related prior art, for example, a hydrophilic polyurethane resin for moisture-permeable waterproof fabric obtained by reacting a hydrophilic polyol such as polyethylene glycol, a chain extender such as ethylene glycol, and an organic isocyanate has been proposed (Patent Documents 1 and 2).

The moisture-permeable film that constitutes the moisture-permeable waterproof fabric is required to have not only moisture permeability, but also washability, alcohol resistance, light resistance, and flexibility. When manufacturing a moisture-permeable waterproof fabric with a three-layer structure as described above, the adhesive layer is usually formed using a solvent-based or moisture-curing adhesive. For this reason, the moisture-permeable film is also required to have the property of being resistant to shrinkage, etc. when adhesive is applied (so-called suitability for overcoating), and to have appropriate heat resistance so that it is not easily softened by heating during adhesion.

JP 2003-201675 A Japanese Patent Application Laid-Open No. 10-17764

However, while the moisture-permeable films formed using conventional hydrophilic polyurethane resins proposed in Patent Documents 1 and 2 and the like exhibit a certain degree of moisture permeability, they are not necessarily sufficient in terms of washability, alcohol resistance, suitability for recoating, heat resistance, light resistance, and flexibility, and there is room for further improvement.

The present invention was made in consideration of the problems associated with the conventional technology, and its objective is to provide a polyurethane resin that can be used to produce a moisture-permeable film that has excellent moisture permeability, as well as excellent washability, alcohol resistance, recoatability, heat resistance, light resistance, and flexibility.

The object of the present invention is to provide a moisture-permeable film obtained using this polyurethane resin, which has excellent moisture permeability, as well as excellent washability, alcohol resistance, suitability for overcoating, heat resistance, light resistance, and flexibility, and to provide a moisture-permeable, waterproof fabric equipped with this moisture-permeable film.

That is, according to the present invention, there is provided the following polyurethane resin.
[1] A polyurethane resin which is a reaction product of (i) a polyol component, (ii) a chain extender, and (iii) a polyisocyanate component, wherein the (i) polyol component includes (i-1) polyethylene glycol and (i-2) a polyether polyol other than the (i-1) polyethylene glycol, and the (ii) chain extender includes (ii-1) two or more linear alkanediols having 2 to 4 carbon atoms, or A polyurethane resin comprising: (ii-1) a linear alkanediol having 2 to 4 carbon atoms; and (ii-2) a linear, branched, or cyclic alkanediol other than the (ii-1) linear alkanediol having 2 to 4 carbon atoms; wherein the (iii) polyisocyanate component comprises (iii-1) an aromatic diisocyanate; and (iii-2) an aliphatic diisocyanate; and wherein the polyurethane resin satisfies at least one of the following requirements (1) and (2):
Requirement (1): The (ii) chain extender further contains (ii-3) a triol.
Requirement (2): The (iii) polyisocyanate component further contains (iii-3) a trifunctional or higher polyfunctional isocyanate.
[2] The polyurethane resin according to [1], wherein the amount of the (i-2) polyether polyol in the (i) polyol component is 30 to 70 mass%.
[3] The polyurethane resin according to [1] or [2], wherein the (ii-3) triol is trimethylolpropane.
[4] The polyurethane resin according to any one of [1] to [3], wherein the amount of the triol (ii-3) is 0.06 to 0.5 parts by mass relative to 100 parts by mass of the polyol component (i).
[5] The polyurethane resin according to any one of [1] to [4], wherein the amount of the polyfunctional isocyanate (iii-3) relative to the aromatic diisocyanate (iii-1) is 0.1 to 0.65 mol%.
[6] The polyurethane resin according to any one of [1] to [5], wherein at least one of the (i) polyol component, the (ii) chain extender, and the (iii) polyisocyanate component is a plant-derived compound.
[7] The polyurethane resin according to any one of [1] to [6] above, which is used as a constituent material of a moisture-permeable film.

Furthermore, according to the present invention, there is provided the following moisture-permeable film.
[8] A moisture-permeable film formed from the polyurethane resin described in [7] above.

Furthermore, according to the present invention, there is provided a moisture-permeable, waterproof fabric as shown below.
[9] A moisture-permeable waterproof fabric comprising a base fabric and a surface layer provided on the surface of the base fabric, the surface layer being the moisture-permeable film described in [8].
[10] The moisture-permeable waterproof fabric described in [9], further comprising an adhesive layer provided between the base fabric and the surface layer.
[11] The moisture-permeable waterproof fabric according to [9] or [10], further comprising a porous layer provided between the base fabric and the surface layer.

The present invention provides a polyurethane resin that can be used to produce a moisture-permeable film that has excellent moisture permeability, washability, alcohol resistance, recoatability, heat resistance, light resistance, and flexibility.

The present invention also provides a moisture-permeable film obtained using this polyurethane resin that has excellent moisture permeability, as well as excellent washability, alcohol resistance, suitability for overcoating, heat resistance, light resistance, and flexibility, and a moisture-permeable, waterproof fabric that includes this moisture-permeable film.

1 is a cross-sectional view showing a schematic diagram of one embodiment of a moisture-permeable waterproof fabric of the present invention. FIG. 2 is a cross-sectional view showing a schematic diagram of another embodiment of the moisture-permeable waterproof fabric of the present invention. FIG. 2 is a schematic diagram illustrating the shape of a sample used in the evaluation of the examples. FIG. 2 is a schematic diagram illustrating the configuration of a gear oven used in the evaluation of the examples.

<Polyurethane resin>
Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. One embodiment of the polyurethane resin of the present invention is a polyurethane resin which is a reaction product of (i) a polyol component, (ii) a chain extender, and (iii) a polyisocyanate component, and is suitable as a material for producing a moisture-permeable film. Hereinafter, the polyurethane resin of the present invention will be described in detail.

(i) Polyol Component
The (i) polyol component includes (i-1) polyethylene glycol and (i-2) a polyether polyol other than the (i-1) polyethylene glycol. It is preferable that the (i) polyol component is substantially composed of only the (i-1) polyethylene glycol and the (i-2) polyether polyol.

[(i-1) Polyethylene glycol]
(i-1) Polyethylene glycol is a hydrophilic polyol that can contribute to the moisture permeability of the film to be formed. (i-1) Polyethylene glycol has a number average molecular weight (Mn) of preferably 600 to 10,000, and more preferably 1,000 to 7,000.

[(i-2) Polyether polyol]
The polyether polyol (i-2) is a component that improves the mechanical properties of the film formed. The number average molecular weight (Mn) of the polyether polyol (i-2) is preferably 650 to 3,000, and more preferably 1,000 to 2,500.

(i-2) Examples of polyether polyols include polypropylene glycol, polyethylene glycol-polytetramethylene glycol (block or random), polytrimethylene ether glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol. Among these, polytrimethylene ether glycol and polytetramethylene ether glycol are preferred from the standpoint of flexibility, etc.

(i-2) Polyether polyol can be obtained, for example, by polymerizing or copolymerizing either an alkylene oxide (propylene oxide, butylene oxide, etc.) or a heterocyclic ether (tetrahydrofuran, 2-methyltetrahydrofuran, etc.). (i-2) Polyether polyol can also be obtained by a dehydration condensation reaction of a diol such as 1,3-propanediol.

From the viewpoint of producing an environmentally friendly resin or film, it is preferable that the polyether polyol (i-2) is a plant-derived compound. Examples of the polyether polyol (i-2) that is a plant-derived compound include polyether polyols made from plant-derived diols and tetrahydrofuran, etc.

In the (i) polyol component (the sum of (i-1) polyethylene glycol and (i-2) polyether polyol), the amount of (i-2) polyether polyol (hydrophobic polyol) is preferably 30 to 70% by mass, and more preferably 35 to 60% by mass. By setting the amount of (i-2) polyether polyol in the (i) polyol component within the above range, a polyurethane resin can be obtained that can produce a moisture-permeable film with an excellent balance between moisture permeability and flexibility.

(ii) Chain Extenders
(ii) The chain extender includes (ii-1) two or more linear alkanediols having 2 to 4 carbon atoms, or (ii-1) a linear alkanediol having 2 to 4 carbon atoms and (ii-2) a linear, branched, or cyclic alkanediol other than the linear alkanediol having 2 to 4 carbon atoms (ii-1). That is, by combining two or more alkanediols having different alkylene carbon numbers, etc., and using them as the chain extender (ii), it is possible to obtain a polyurethane resin capable of producing a moisture-permeable film having improved recoating suitability, which is less likely to shrink even when a solvent-based adhesive is applied, compared to the case where only one type of alkanediol is used as a chain extender. The reason why such an effect is obtained is not necessarily clear, but it is presumed that the combination of two or more alkanediols having different alkylene carbon numbers, etc., creates a moderate amount of "play" in the molecular chain of the polyurethane resin, resulting in a slight decrease in crystallinity.

The amount of (ii) chain extender is preferably 0.2 to 40 mass%, more preferably 0.5 to 20 mass%, and particularly preferably 12 to 16 mass%, based on the total amount of (i) polyol component and (ii) chain extender. It is preferable that (ii) chain extender is substantially free of an amine compound. When an amine compound is used as a chain extender, the heat resistance of the resulting moisture-permeable film tends to decrease.

[(ii-1) Linear alkanediol having 2 to 4 carbon atoms]
Examples of the (ii-1) linear alkanediol having 2 to 4 carbon atoms include ethylene glycol, 1,3-propanediol, and 1,4-butanediol. From the viewpoint of producing an environmentally friendly resin or film, the (ii-1) linear alkanediol having 2 to 4 carbon atoms may be a plant-derived compound. Examples of the (ii-1) linear alkanediol having 2 to 4 carbon atoms that is a plant-derived compound include, for example, plant-derived ethylene glycol, 1,3-propanediol, and 1,4-butanediol. In addition, a plant-derived linear alkanediol can be combined with a petroleum-derived linear alkanediol.

[(ii-2) Linear, branched, or cyclic alkanediol]
As the linear alkanediol, a linear alkanediol having 5 or more carbon atoms can be used. Examples of the linear alkanediol having 5 or more carbon atoms include 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol.

As the branched alkanediol, a branched alkanediol having 3 or more carbon atoms can be used. Examples of branched alkanediols having 3 or more carbon atoms include 1,3-butanediol, 3-methyl-1,5-pentanediol (MPD), neopentyl glycol (NPD), 2-methylpropanediol, 2,2-dimethylpropanediol, 2-propyl-1,4-butanediol, 2-isopropyl-1,4-butanediol, 2-cyclopropyl-1,4-butanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 2-butyl-1,4-butanediol, 2-isobutyl-1,4-butanediol, 2-methyl-1,3-pentanediol, 2,2 ,4-trimethyl-1,3-pentanediol, 2-propyl-1,5-pentanediol, 2-isopropyl-1,5-pentanediol, 2-cyclopropyl-1,5-pentanediol, 2-butyl-1,5-pentanediol, 2-propyl-1,6-hexanediol, 2-isopropyl-1,6-hexanediol, 2-cyclopropyl-1,6-hexanediol, 2-butyl-1,6-hexanediol, 2-propyl-1,7-heptanediol, 2-isopropyl-1,7-heptanediol, 2-cyclopropyl-1,7-heptanediol, 2-butyl ethyl-1,7-heptanediol, 2-methyl-1,8-octanediol, 2-propyl-1,8-octanediol, 2-isopropyl-1,8-octanediol, 2-cyclopropyl-1,8-octanediol, 2-butyl-1,8-octanediol, 2-propyl-1,9-nonanediol, 2-isopropyl-1,9-nonanediol, 2-cyclopropyl-1,9-nonanediol, 2-butyl-1,9-nonanediol, 2-cyclobutyl-1,9-nonanediol, 2-propyl-1,10-decanediol, 2-isopropyl-1,10-decanediol Examples of the cyclopropyl-1,10-decanediol include 2-cyclopropyl-1,10-decanediol, 2-butyl-1,10-decanediol, 2-propyl-1,11-undecanediol, 2-isopropyl-1,11-undecanediol, 2-cyclopropyl-1,11-undecanediol, 2-butyl-1,11-undecanediol, 2-dodecyl-1,11-undecanediol, 2-propyl-1,12-dodecanediol, 2-isopropyl-1,12-dodecanediol, 2-cyclopropyl-1,12-dodecanediol, and 2-butyl-1,12-dodecanediol.

Cyclic alkanediols include 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 2,2'-bis(4-hydroxycyclohexyl)propane.

(iii) Polyisocyanate Component
(iii) The polyisocyanate component is a compound having two or more isocyanate groups (NCO groups) in one molecule, and includes (iii-1) an aromatic diisocyanate and (iii-2) an aliphatic diisocyanate.

[(iii-1) Aromatic diisocyanate]
(iii-1) Examples of aromatic diisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), 2,2'-MDI, 2,4'-MDI, 2,4-tolylene diisocyanate (TDI), 2,6-TDI, m-xylylene diisocyanate (XDI), 1,4-phenylene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, and benzidine diisocyanate. Among these, MDI is preferred.

[(iii-2) Aliphatic diisocyanate]
(iii-2) Examples of the aliphatic diisocyanate include aliphatic diisocyanates such as 1,4-tetramethylene diisocyanate, 1,5-pentane diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), and 1,10-decamethylene diisocyanate; and alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated XDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), and 1-methylcyclohexane-2,4-diisocyanate (hydrogenated TDI). Among these, HDI and plant-derived PDI are preferred.

The mass ratio of the aromatic diisocyanate (iii-1) to the aliphatic diisocyanate (iii-2) is preferably (iii-1):(iii-2) = 30:70 to 85:15, and more preferably 60:40 to 80:20. If the amount of the aromatic diisocyanate (iii-1) is too large, the moisture-permeable film formed tends to be hard. On the other hand, if the amount of the aliphatic diisocyanate (iii-2) is too large, the moisture-permeable film formed tends to be soft. In addition, the amount of the aliphatic diisocyanate (iii-2) is preferably 10 to 85 mol%, more preferably 20 to 60 mol%, and particularly preferably 30 to 40 mol%, based on the total amount of the polyisocyanate component (iii).

From the viewpoint of producing an environmentally friendly resin or film, it is preferable that at least one of (i) the polyol component, (ii) the chain extender, and (iii) the polyisocyanate component is a plant-derived compound.

(Requirements (1) and (2))
The polyurethane resin of the present embodiment satisfies at least one of the following requirements (1) and (2).
Requirement (1): (ii) The chain extender further contains (ii-3) a triol.
Requirement (2): (iii) the polyisocyanate component further contains (iii-3) a trifunctional or higher polyfunctional isocyanate.

If the amount of hard segments in the polyurethane resin, which is the raw material, is simply increased in order to improve the properties of the moisture-permeable film, such as alcohol resistance and heat resistance, the flexibility (texture, etc.) of the moisture-permeable film is likely to be impaired. In contrast, the polyurethane resin of this embodiment, which satisfies at least one of the above requirements (1) and (2), that is, which is reacted with a compound having three or more functional groups, such as (ii-3) triol or (iii-3) polyfunctional isocyanate, is a branched polymer (thermoplastic resin) having an internal crosslinked structure. By making such an internal crosslinked structure, the polyurethane resin of this embodiment can produce a moisture-permeable film with improved properties, such as washing resistance, alcohol resistance, and heat resistance, while maintaining flexibility. In contrast, if a compound having three or more functional groups, such as (ii-3) triol or (iii-3) polyfunctional isocyanate, is reacted after the synthesis of the polyurethane resin, it is likely to become a thermosetting resin having a so-called network structure, and the flexibility (texture) may be poor.

[(ii-3) Triol]
The (ii-3) triol is a trifunctional polyol having three hydroxyl groups (OH groups) in one molecule. The molecular weight (chemical formula weight) of the (ii-3) triol is preferably 500 or less, more preferably 300 or less. Examples of the (ii-3) triol include glycerin, trimethylolethane, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, heptanetriol, and octanetriol. Among these, glycerin and trimethylolpropane are preferred, and trimethylolpropane is more preferred.

When the polyurethane resin of this embodiment satisfies requirement (1), the amount of (ii-3) triol per 100 parts by mass of (i) polyol component is preferably 0.06 to 0.5 parts by mass, and more preferably 0.1 to 0.45 parts by mass. By setting the amount of (ii-3) triol per 100 parts by mass of (i) polyol component within the above range, a polyurethane resin can be obtained that can produce a moisture-permeable film with further improved washing resistance, alcohol resistance, and heat resistance.

[(iii-3) Polyfunctional isocyanate]
(iii-3) Polyfunctional isocyanate is a trifunctional or higher polyfunctional isocyanate having three or more isocyanate groups (NCO groups) in one molecule. (iii-3) Polyfunctional isocyanate includes diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate and isophorone diisocyanate; trimethylolpropane adducts, biuret and nurate forms thereof; polymeric MDI; terminal isocyanate prepolymer; and the like. Also, polyisocyanates of these block forms can be used. Among these, adducts, biuret and nurate forms of aliphatic diisocyanates such as hexamethylene diisocyanate and pentamethylene diisocyanate are preferred.

When the polyurethane resin of this embodiment satisfies requirement (2), the amount of (iii-3) polyfunctional isocyanate relative to (iii-1) aromatic diisocyanate is preferably 0.1 to 0.65 mol%, and more preferably 0.2 to 0.5 mol%. By setting the amount of (iii-3) polyfunctional isocyanate relative to (iii-1) aromatic diisocyanate within the above range, a polyurethane resin can be obtained that can produce a moisture-permeable film with further improved washing resistance, alcohol resistance, and heat resistance.

(Method of producing polyurethane resin)
The polyurethane resin can be produced, for example, by reacting (i) a polyol component, (ii) a chain extender, and (iii) a polyisocyanate component by a one-shot method or a multi-stage method, preferably at 60 to 150°C, more preferably at 60 to 110°C. A catalyst may be used in combination during the reaction, if necessary. Examples of the catalyst include metal salts and organometallic derivatives such as dibutyltin laurate, dioctyltin laurate, stannous octoate, lead octoate, and tetra-n-butyl titanate; organic amines such as triethylamine; and diazabicycloundecene catalysts.

(i) The polyol component, (ii) the chain extender, and (iii) the polyisocyanate component can be reacted in the presence of a solvent such as an organic solvent. By reacting in the presence of a solvent, the polyurethane resin can be obtained in the form of a solution in which it is dissolved in the solvent, or in the form of a dispersion in which it is dispersed. Examples of the solvent include organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, N-ethylpyrrolidone, β-alkoxypropionamide, dipropylene glycol dimethyl ether, and ethyl acetate.

The polyurethane resin solution or dispersion may contain appropriate amounts of various additives, such as thermoplastic resins, tackifying resins, catalysts, pigments, antioxidants, UV absorbers, surfactants, flame retardants, fillers, and foaming agents, as necessary.

<Moisture permeable film>
One embodiment of the moisture-permeable film of the present invention is a moisture-permeable and waterproof film formed from the polyurethane resin described above. That is, since the moisture-permeable film of this embodiment is a film formed from the polyurethane resin described above, it has excellent moisture permeability, and is also excellent in washing resistance, alcohol resistance, recoating suitability, heat resistance, light resistance, and flexibility. Therefore, the moisture-permeable film of this embodiment is suitable as a material for constituting a moisture-permeable waterproof fabric.

A moisture-permeable film can be produced, for example, by applying a solution or dispersion of polyurethane resin to a substrate such as release paper, and then drying to remove the solvent. Methods for applying a solution of polyurethane resin to a substrate (coating method) include conventionally known coating methods such as the comma coating method, knife coating method, roll coating method, gravure coating method, and spray coating method.

The thickness of the moisture-permeable film may be set appropriately within a range that exhibits moisture permeability and waterproofing, for example, within the range of 10 to 15 μm. The thickness of the moisture-permeable film may be set appropriately by changing the thickness of the coating film formed by applying a polyurethane resin solution or the like to the substrate.

The 100% modulus of the moisture-permeable film at 25°C is usually 3.0 to 5.0 MPa, preferably 3.5 to 4.5 MPa. The 20% modulus of the moisture-permeable film at 25°C is usually 1.5 to 4.0 MPa, preferably 1.8 to 3.7 MPa. The moisture-permeable film of this embodiment, whose 100% modulus and 20% modulus values are both within the above ranges, maintains a better balance between properties such as washability and flexibility (feel).

<Breathable waterproof fabric>
FIG. 1 is a cross-sectional view showing an embodiment of the moisture-permeable waterproof fabric of the present invention. As shown in FIG. 1, the moisture-permeable waterproof fabric 100 of this embodiment includes a base fabric 2 and a surface layer 4 provided on the surface of the base fabric 2. The surface layer 4 is the moisture-permeable film formed of a specific polyurethane resin. The moisture-permeable waterproof fabric 100 of this embodiment has a moisture-permeable and waterproof film as the surface layer 4, which is also excellent in wash resistance, alcohol resistance, recoating suitability, heat resistance, light resistance, and flexibility. Therefore, the moisture-permeable waterproof fabric 100 of this embodiment is excellent in moisture permeability and waterproofness, and is also excellent in wash resistance, alcohol resistance, heat resistance, light resistance, and flexibility.

FIG. 2 is a cross-sectional view showing a schematic diagram of another embodiment of the moisture-permeable waterproof fabric of the present invention. The moisture-permeable waterproof fabric 200 of the embodiment shown in FIG. 2 further includes a porous layer 6 and an adhesive layer 8 provided between the base fabric 2 and the surface layer 4. That is, the surface layer 4 may be fixed onto the base fabric 2 via the adhesive layer 8, or may be fixed onto the base fabric 2 via the porous layer 6 and the adhesive layer 8.

The adhesive layer 8 can be formed, for example, from a two-component curing urethane adhesive that is used in the manufacture of conventional fabrics, including moisture-permeable waterproof fabrics. The porous layer 6 is a layer similar to the porous layers that make up conventional moisture-permeable waterproof fabrics, and can be formed, for example, from urethane resin, acetyl cellulose, epoxy resin, etc.

Examples of the base fabric 2 include woven fabrics such as twill weave and plain weave, brushed fabrics obtained by mechanically brushing the cotton fabric of the woven fabric, rayon fabric, nylon fabric, polyester fabric, Kevlar fabric, nonwoven fabrics (polyester, nylon, various latex), various films, sheets, etc.

The moisture-permeable waterproof fabric can be manufactured, for example, by adhering the moisture-permeable film manufactured by the above-mentioned method to a base fabric using an adhesive. In addition, to manufacture a moisture-permeable waterproof fabric 100 in which a moisture-permeable film, which is a skin layer 4, is provided directly on a base fabric 2 as shown in FIG. 1, a solution or dispersion of polyurethane resin can be applied to the base fabric 2 to the desired thickness and then dried.

The present invention will be specifically explained below based on examples, but the present invention is not limited to these examples. Note that "parts" and "%" in the examples and comparative examples are based on mass unless otherwise specified.

<Production of Polyurethane Resin>
Example 1
In a glass reaction vessel equipped with a stirrer and a thermometer, (i) 17.9 parts of polyethylene glycol 2000 (number average molecular weight: 2,000), 41.7 parts of polytetramethylene glycol 2000 (number average molecular weight: 2,000), 3.6 parts of ethylene glycol, 5.2 parts of 1,4-butanediol, and 0.2 parts of trimethylolpropane were placed as the polyol component and (ii) chain extender. Then, 163.9 parts of dimethylformamide (DMF) and 70.2 parts of methyl ethyl ketone (MEK) were added, and the mixture was stirred at 50°C for 30 minutes. Next, (iii) 10.0 parts of hexamethylene diisocyanate and 21.9 parts of diphenylmethane diisocyanate were added as the polyisocyanate component, and the mixture was reacted at 80°C for 3 hours to obtain a solution containing a polyurethane resin. The resulting solution had a solids content of 30.0% and a viscosity at 25° C. of 1,000 dPa·s.

(Examples 2 to 30, Comparative Examples 1 to 9)
Solutions containing polyurethane resins were obtained in the same manner as in Example 1, except that the compositions (unit: parts) shown in the upper rows of Tables 1-1 to 1-4 were used. The solid content of each of the obtained solutions was 30.0%. Details of the materials used are shown in Tables 2 to 4.

<Production of breathable waterproof fabric>
(Standard fabric)
(1) Production of moisture-permeable film 100 parts of a solvent-based urethane resin (trade name "Heimullen Y-286FM", manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), 10 parts of DMF, and 5 parts of MEK were mixed to obtain a mixture liquid for a surface layer. Using a clearance coater, the mixture liquid for a surface layer obtained was uniformly coated on a release paper in a coating amount of 50 μm wet. After drying at 80° C. for 2 minutes, it was further dried at 120° C. for 3 minutes to obtain a moisture-permeable film (surface layer) having a film thickness of 10 to 15 μm.

(2) Adhesion of the Surface Layer and the Base Fabric 100 parts of a solvent-based urethane resin (trade name "Y-173", Dainichiseika Color & Chemicals Mfg. Co., Ltd.), 10 parts of a solvent-based polyisocyanate crosslinking agent A (trade name "Rezamin NE-crosslinking agent", Dainichiseika Color & Chemicals Mfg. Co., Ltd.), 1 part of a solvent-based polyisocyanate crosslinking agent B (trade name "Rezamin UD-crosslinking agent", Dainichiseika Color & Chemicals Mfg. Co., Ltd.), 20 parts of DMF, and 40 parts of MEK were mixed to obtain a mixture liquid for the adhesive layer. The mixture liquid for the adhesive layer obtained was applied onto the surface layer (moisture-permeable film) and dried to form an adhesive layer. A base fabric (nylon taffeta) was laminated onto the formed adhesive layer and heated and pressed at a lamination temperature of 40°C. Thereafter, the mixture was aged at 50°C for 48 hours to obtain a standard moisture-permeable and waterproof fabric.

(Fabric for evaluation)
Fabrics for evaluation were obtained in the same manner as in the case of the above-mentioned standard fabric, except that the solutions containing the produced polyurethane resins were used instead of the blended liquid for the surface layer.

<Evaluation>
Among the evaluation criteria shown below, "◎", "◯", and "△" were evaluated as pass, and "×" was evaluated as fail. The evaluation results are shown in Table 5.

(Texture)
The produced standard fabric and the evaluation fabric were compared in terms of feel when touched with the hand, and the feel (softness) was evaluated according to the following evaluation criteria.
⊚: The evaluation fabric was softer than the standard fabric.
◯: The evaluation fabric was as soft as the standard fabric.
×: The evaluation fabric was harder than the standard fabric.

(Suitability for recoating)
When bonding the surface layer and the base fabric, the state of the surface layer was visually confirmed immediately after application of the adhesive layer compound liquid and after drying, and the recoatability was evaluated according to the following evaluation criteria. Note that for Comparative Example 4, the surface layer (film) dissolved immediately after application of the adhesive layer compound liquid, so the recoatability could not be evaluated.
○: No swelling was observed.
△: Slight swelling was observed.
×: Swelling was observed over the entire surface, or the epidermis was dissolved.

(Film properties)
The polyurethane resin solutions thus produced were each applied to release paper, and then dried at 80°C for 2 minutes and at 120°C for 3 minutes. After drying, the film was peeled off from the release paper to obtain a semi-transparent film having a thickness of 50 μm, a width of 1.5 cm, and a length of 6 cm. Using an autograph (product name "AGS-J", manufactured by Shimadzu Corporation), the obtained semi-transparent film was pulled at a speed of 200 mm/min under conditions of a temperature of 25°C and a humidity of 30% RH or less, and the 20% modulus (MPa) and 100% modulus (MPa) were measured.

(Thermal softening point)
The semi-transparent film (thickness 50 μm, width 1.5 cm, length 6 cm) prepared in the above-mentioned "Film Properties" was used as a test piece. As shown in FIG. 3, clips 12 were attached to the top and bottom of the film 10, and the clips 12 were further fixed with cellophane tape. A weight 14 was attached to one of the clips 12 so that a load of 450 g/cm ² was applied when the film 10 was hung, to prepare a sample 16. The center (2 cm) of the film 10 was not covered with cellophane tape. Next, as shown in FIG. 4, the clip 12 of the sample 16 to which the weight 14 was not attached was attached to the rotating disk 22 of the gear oven 20. Thereafter, the temperature inside the gear oven 20 was raised from room temperature at a rate of 3° C./min while rotating the rotating disk 22 at 5 rpm, and the temperature (thermal softening point (° C.)) when the film 10 was broken was measured.

(Alcohol resistance)
The prepared polyurethane resin solutions were applied to release paper and then dried at 80°C for 2 minutes and 120°C for 3 minutes. After drying, the films were peeled off from the release paper to obtain films with a thickness of 50 μm, a width of 5 cm, and a length of 5 cm. The obtained films were immersed in ethanol for 10 minutes and then removed. The linear swelling ratio (= {(width of film after immersion)/(width of film before immersion)}×100(%)) of the removed films was calculated, and the solvent resistance was evaluated according to the following evaluation criteria.
A: The linear swelling rate of one side of the film was less than 200%.
Δ: The linear swelling rate of one side of the film was 200% or more.
×: The film was dissolved.

(Light resistance)
The prepared polyurethane resin solutions were each applied onto a release paper, and then dried at 80°C for 2 minutes and 120°C for 3 minutes. After drying, the film was peeled off from the release paper to obtain a film having a thickness of 50 μm, a width of 8 cm, and a length of 15 cm. A xenon weatherometer was used to carry out an accelerated light resistance test on the obtained film at 70±3°C and irradiation energy of 20 MJ. Using a tensile tester, the breaking strength of the film was measured before and after the accelerated light resistance test at 25°C and a tensile speed of 200 mm/min, and the light resistance was evaluated according to the following evaluation criteria.
A: The retention of breaking strength was 50% or more.
Δ: The retention rate of breaking strength was 25% or more and less than 50%.
x: The retention of breaking strength was less than 25%, or the film was dissolved.

(Moisture permeability)
The moisture permeability (g/m ² ·24h) of the evaluation fabric was measured by a method conforming to the "calcium acetate method (B-1 method)" of JIS L 1099:2012. In addition, when the moisture permeability was 40,000 g/m ² ·24h or more, it was evaluated as "○", when it was 20,000 g/m ² ·24h or more and less than 40,000 g/m ² ·24h, it was evaluated as "△", and when it was less than 20,000 g/m ² ·24h, it was evaluated as "×". In addition, (ii) the film formed from the solution containing the polyurethane resin of Comparative Example 5 produced without using a chain extender was extremely soft and broke during the measurement, so the moisture permeability could not be measured.

(Washing resistance)
The fabric for evaluation was alternately washed 20 times in total according to the "C-type standard washing machine (palasator type)" of JIS L 1930:2014 and dried according to the "Drying C method (flat drying)". The water pressure resistance of the fabric for evaluation before and after washing and drying was measured according to the "B method (high water pressure method)" of JIS L 1092:2009, and the wash resistance was evaluated according to the following evaluation criteria.
⊚: Water pressure resistance retention was 80% or more.
◯: Water pressure resistance retention was 70% or more and less than 80%.
×: Water pressure resistance retention was less than 70%.

The polyurethane resin of the present invention is useful as a material for forming a moisture-permeable film that constitutes a moisture-permeable, waterproof fabric, etc.

2: Base fabric 4: Surface layer 6: Porous layer 8: Adhesive layer 10: Film 12: Clip 14: Weight 16: Sample 20: Gear oven 22: Rotating disk 100, 200: Moisture-permeable waterproof fabric

Claims (11)

A polyurethane resin that is a reaction product of (i) a polyol component, (ii) a chain extender, and (iii) a polyisocyanate component,
The (i) polyol component contains (i-1) polyethylene glycol and (i-2) a polyether polyol other than the (i-1) polyethylene glycol,
The (ii) chain extender contains (ii-1) two or more linear alkanediols having 2 to 4 carbon atoms, or
(ii-1) a linear alkanediol having 2 to 4 carbon atoms; and (ii-2) a linear, branched, or cyclic alkanediol other than the (ii-1) linear alkanediol having 2 to 4 carbon atoms,
The (iii) polyisocyanate component includes (iii-1) an aromatic diisocyanate and (iii-2) an aliphatic diisocyanate;
A polyurethane resin that satisfies at least one of the following requirements (1) and (2):
Requirement (1): The (ii) chain extender further contains (ii-3) a triol.
Requirement (2): The (iii) polyisocyanate component further contains (iii-3) a trifunctional or higher polyfunctional isocyanate. The polyurethane resin according to claim 1, wherein the amount of the polyether polyol (i-2) in the polyol component (i) is 30 to 70 mass %. The polyurethane resin according to claim 1 or 2, wherein the (ii-3) triol is trimethylolpropane. The polyurethane resin according to any one of claims 1 to 3, wherein the amount of the triol (ii-3) is 0.06 to 0.5 parts by mass per 100 parts by mass of the polyol component (i). The polyurethane resin according to any one of claims 1 to 4, wherein the amount of the polyfunctional isocyanate (iii-3) relative to the aromatic diisocyanate (iii-1) is 0.1 to 0.65 mol%. The polyurethane resin according to any one of claims 1 to 5, wherein at least one of the (i) polyol component, the (ii) chain extender, and the (iii) polyisocyanate component is a plant-derived compound. The polyurethane resin according to any one of claims 1 to 6, which is used as a constituent material for a moisture permeable film. A moisture-permeable film formed from the polyurethane resin described in claim 7. The present invention comprises a base fabric and a surface layer provided on a surface of the base fabric,
A moisture-permeable waterproof fabric, wherein the surface layer is the moisture-permeable film according to claim 8. The moisture-permeable waterproof fabric according to claim 9, further comprising an adhesive layer provided between the base fabric and the surface layer. The moisture-permeable waterproof fabric according to claim 9 or 10, further comprising a porous layer provided between the base fabric and the surface layer.

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