KR102884218B1 - Sheet-shaped article and method for manufacturing the same - Google Patents

Abstract

The present invention aims to provide a sheet-shaped article having both a flexible texture and excellent light resistance, and a method for producing the same. In order to achieve the above object, the sheet-shaped article of the present invention has the following composition. That is, it is a sheet-shaped article containing a polymer elastomer in a fibrous substrate, wherein the fibrous substrate includes ultrafine fibers having an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastomer has a hydrophilic group, and further includes polyetherdiol as a constituent component, and has an N-acylurea bond and/or an isourea bond inside the polymer elastomer, and the sheet-shaped article satisfies the following conditions 1 and 2. Condition 1: The longitudinal strength specified by a specific standard is 40 mm or more and 140 mm or less. Condition 2: The wear loss in 20,000 cycles of a Martindale abrasion test specified by JIS L 1096:2005 after a light resistance test measured under conditions specified by a specific standard is 25 mg or less.

Description

Sheet-shaped article and method for manufacturing the same

The present invention relates to a sheet-shaped article and a method for producing the same, and more particularly to a sheet-shaped article having excellent flexibility and light resistance and a method for producing the same.

Sheet materials, primarily composed of fibrous substrates such as nonwoven fabrics and polyurethane, possess superior characteristics not found in natural leather and are widely used in various applications, including artificial leather. In particular, sheet materials using polyester-based fibrous substrates exhibit excellent formability, leading to an increasing number of applications each year, including clothing, chair covers, and automotive interior materials.

In manufacturing such sheet-shaped articles, a combination of processes is generally employed: impregnating a fibrous substrate with an organic solvent solution of polyurethane, and then immersing the obtained fibrous substrate in a non-solvent solution of water or an organic solvent for polyurethane to wet-coagulate the polyurethane. In this case, as the organic solvent that is the solvent for polyurethane, a water-miscible organic solvent such as N,N-dimethylformamide is used; however, since organic solvents are generally highly harmful to the environment, there is a strong demand for a method that does not use an organic solvent when manufacturing sheet-shaped articles.

As a specific solution, a method of using water-dispersed polyurethane in which polyurethane resin is dispersed in water instead of conventional organic solvent-based polyurethane is being examined, but there is a problem that sheet-shaped products solidified using water-dispersed polyurethane are prone to having a hard texture.

One of the main reasons for this is the difference in the coagulation methods of the two. Specifically, organic solvent-based polyurethane coagulates by displacing the polyurethane molecules dissolved in the organic solvent with water, a so-called wet coagulation method. This coagulation process results in the formation of a low-density porous polyurethane film. Therefore, even when polyurethane is impregnated into a fibrous substrate and coagulated, the bonding area between the fibers and the polyurethane is reduced, resulting in a flexible sheet-like product.

Meanwhile, water-dispersed polyurethanes are mainly coagulated by the so-called moist heat coagulation method, which involves heating to disrupt the hydration state of the water-dispersed polyurethane dispersion and coagulate the polyurethane emulsions together. The resulting polyurethane membrane structure is a high-density, non-porous membrane. Therefore, the adhesion between the fibrous substrate and the polyurethane is dense, and the intertwined portions of the fibers are strongly gripped, resulting in a hard texture.

Up to now, in order to obtain a sheet-shaped article with a flexible texture using a water-dispersible polyurethane, a method has been proposed in which, for example, a thickener is added to a solution containing a water-dispersible polyurethane, and a fibrous substrate impregnated with the solution is treated with hot water, thereby reducing the polyurethane film covering the fibrous substrate and obtaining a flexible texture (Patent Document 1).

As for the coagulation method using the same hot water treatment, a method is proposed for obtaining a sheet-shaped article having excellent moisture and heat resistance by performing a curing treatment after dyeing to prevent deterioration of physical properties due to polyurethane swelling during dyeing (Patent Document 2), and a method is proposed for obtaining a sheet-shaped article having excellent light resistance such as light yellowing resistance and light dyeing fastness and flexibility by applying a water-dispersible polyurethane containing a hindered amine compound (Patent Document 3).

In addition, a method for obtaining a flexible texture is proposed by dissolving and mixing inorganic salts in a nonionic, water-dispersible polyurethane that has been forcibly emulsified, thereby adjusting the thermal gelation temperature, which is the temperature at which the water-dispersible polyurethane gels, and suppressing the phenomenon in which the particles of the polymer emulsion dispersed in water are concentratedly attached to the surface layer of a sheet-shaped object due to the movement of water, the so-called migration phenomenon (Patent Document 4).

In addition, a method is proposed for impregnating a sheet-shaped material with a water-dispersible polyurethane containing a polysaccharide, heating and drying the sheet at two temperatures to form a porous structure of a polymer elastomer, and making the texture flexible (Patent Document 5). In this method, in the first drying step, the polymer elastomer is completely solidified while the polysaccharide has retained moisture, and in the second drying step, while the polymer elastomer is completely solidified, the moisture retained by the polysaccharide contained in the polymer elastomer is evaporated, so that the portions where the moisture retained by the polysaccharide existed become voids, thereby forming a porous structure.

Alternatively, a method has been proposed in which a cross-linking agent is applied to a sheet-shaped product formed by coagulating a water-dispersed polyurethane, heating the product, and reacting the product to maintain the texture prior to the addition of the cross-linking agent (Patent Document 6). This method allows the water-dispersed polyurethane and the cross-linking agent to react regardless of the polyurethane coagulation method, thereby maintaining a state close to the original polyurethane coagulation structure.

International Publication No. 2015/129602 Japanese Patent Publication No. 2017-172074 Japanese Patent Publication No. 2000-265052 Japanese Patent Publication No. Hei 6-316877 Japanese Patent Publication No. 2019-112742 International Publication No. 2016/052189

However, when using sheet-shaped articles outdoors, such as for automobile interior applications, there is a problem that the polyurethane that binds the fibers in the sheet-shaped article is decomposed by ultraviolet rays contained in sunlight, causing the sheet-shaped article to deteriorate.

Typically, water-dispersible polyurethanes are obtained by reacting a polymer polyol, an organic polyisocyanate, and a chain extender, and exhibit various properties depending on the composition of the polymer polyol. Representative polymer polyols include polyether polyols and polycarbonate polyols. While sheet products using polyether-based polyurethanes offer a more flexible texture than polycarbonate-based polyurethanes, their lightfastness is inferior. To achieve both flexibility and lightfastness, it is necessary to use polyether-based polyurethanes to enhance lightfastness, as this will ensure their durability during actual use.

In the methods disclosed in Patent Documents 1 to 3, although the hardness of the texture can be improved through hydrothermal coagulation, thereby achieving a certain degree of flexibility, the polyurethane cannot fully function as a binder, resulting in insufficient abrasion resistance. In the method disclosed in Patent Document 2, since heating to a high temperature after dyeing causes the dye to sublimate, there is a risk of discoloration in actual use, resulting in insufficient light resistance. Furthermore, in the method disclosed in Patent Document 3, light resistance is improved by including a hindered amine compound, but since the compound is included in a high molecular weight polyol, the film properties are deteriorated, the gripping force for fibers is weak, and the abrasion resistance of the sheet-shaped product is insufficient. Furthermore, flexibility is not sufficient.

In addition, in the method disclosed in Patent Document 4, although a flexible texture can be achieved by suppressing migration, since the polyurethane resin is not crosslinked three-dimensionally, the fibers cannot be sufficiently gripped, resulting in insufficient wear resistance and light resistance.

Meanwhile, the method disclosed in Patent Document 5 achieves a porous structure through a two-stage drying process, but it fails to completely suppress migration, resulting in an inadequate texture. Furthermore, because the polyurethane resin is not cross-linked three-dimensionally, it fails to sufficiently bind fibers, resulting in inadequate abrasion resistance and light resistance.

Alternatively, in the method disclosed in Patent Document 6, the crosslinking agent is impregnated after polyurethane solidification, but since the reaction between the polyurethane and the crosslinking agent does not progress significantly, a three-dimensional structure cannot be sufficiently formed by the polyurethane and the crosslinking agent, resulting in insufficient wear resistance and light resistance.

Therefore, the purpose of the present invention, taking into account the background of the above-mentioned prior art, is to provide a sheet-shaped article having both a flexible texture and excellent light resistance, and a method for manufacturing the same.

In order to achieve the above purpose, the inventors of the present invention have conducted repeated studies and have found that, by controlling the drying temperature in the coagulation of a polymer elastomer containing polyetherdiol as a constituent and using a specific amount of a monovalent cation-containing inorganic salt and a crosslinking agent in combination, not only can a sheet-shaped article be manufactured in a way that is environmentally friendly, but a sheet-shaped article having superior texture and light resistance compared to conventional sheet-shaped articles can be obtained, leading to the present invention.

That is, the present invention is intended to solve the above problem, and the sheet-shaped article of the present invention is a sheet-shaped article containing a polymer elastomer in a fibrous substrate, wherein the fibrous substrate includes ultrafine fibers having an average single fiber diameter of 0.1 µm or more and 10 µm or less, the polymer elastomer has a hydrophilic group, and further includes polyetherdiol as a constituent component, and has an N-acylurea bond and/or an isourea bond inside the polymer elastomer, and is a sheet-shaped article satisfying the following conditions 1 and 2.

Condition 1: The longitudinal strength specified by Method A (45° cantilever method) described in JIS L 1096:2010 “Testing method for raw fabrics of woven and knitted fabrics” is 40 mm or more and 140 mm or less.

Condition 2: The wear loss in 20,000 Martindale abrasion tests specified in JIS L 1096:2005 after a light fastness test measured under the condition of 110 MJ/㎡ of xenon arc dose in JIS L 0843:2006 light fastness measurement method is 25 mg or less.

According to a preferred form of the sheet-shaped article of the present invention, in the sheet-shaped article before the light resistance test, the wear loss in 20,000 Martindale abrasion tests specified by JIS L 1096:2010 is 20 mg or less.

According to a preferred form of the sheet-shaped article of the present invention, it contains 10 mass% or more of the polymer elastomer.

According to a preferred form of the sheet-shaped article of the present invention, the sheet-shaped article additionally satisfies the following condition 3.

Condition 3: When the raised surface of the above sheet-shaped material is placed on a hot plate heated to 150°C and pressed with a pressing load of 2.5 kPa for 10 seconds, the retention rate of the L value is 90% or more and 100% or less.

The method for manufacturing a sheet-shaped article of the present invention is a method for manufacturing a sheet-shaped article, which includes the following processes (1) to (4) in this order.

(1) A polymer elastomer impregnation process in which a fibrous substrate including an ultrafine fiber-forming fiber is impregnated with an aqueous dispersion containing a polymer elastomer, a monovalent cation-containing inorganic salt, and a crosslinking agent, and then heat-treated at a temperature of 120°C or more and 180°C or less, wherein the polymer elastomer has a hydrophilic group and further includes polyetherdiol as a constituent component, and the content of the monovalent cation-containing inorganic salt in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer elastomer.

(2) Ultrafine fiber expression process of treating the above ultrafine fiber expression type fiber with alkali and expressing ultrafine fiber.

(3) Drying process that performs heat treatment at a temperature of 120℃ or higher and 180℃ or lower

(4) A raising process in which at least one side of a sheet-shaped object is raised to form hair on the surface.

According to a preferred embodiment of the method for manufacturing a sheet-shaped article of the present invention, a dyeing process for dyeing a non-woven sheet-shaped article or a sheet-shaped article is included after the drying process.

According to a preferred embodiment of the method for producing a sheet-shaped article of the present invention, the monovalent cation-containing inorganic salt is sodium chloride and/or sodium sulfate.

According to a preferred embodiment of the method for producing a sheet-shaped article of the present invention, the cross-linking agent is a carbodiimide-based cross-linking agent.

According to the present invention, a sheet-shaped article having both a flexible texture and excellent light resistance is obtained.

The sheet-shaped article of the present invention is a sheet-shaped article containing a polymer elastomer in a fibrous substrate, wherein the fibrous substrate includes ultrafine fibers having an average single fiber diameter of 0.1 µm or more and 10 µm or less, the polymer elastomer has a hydrophilic group, and further includes polyetherdiol as a constituent component, and has an N-acylurea bond and/or an isourea bond inside the polymer elastomer, and is a sheet-shaped article satisfying the following conditions 1 and 2.

Condition 1: The longitudinal strength specified by Method A (45° cantilever method) described in JIS L 1096:2010 “Testing method for raw fabrics of woven and knitted fabrics” is 40 mm or more and 140 mm or less.

Condition 2: The wear loss in 20,000 Martindale abrasion tests specified in JIS L 1096:2005 after a light fastness test measured under the condition of 110 MJ/㎡ of xenon arc dose in JIS L 0843:2006 light fastness measurement method is 25 mg or less.

Although the components are described in detail below, the present invention is not limited to the scope described below without going beyond the gist thereof.

[Ultrafine fiber]

Examples of resins that can be used in the ultrafine fibers of the present invention include polyester resins and polyamide resins, from the standpoint of excellent durability, particularly mechanical strength, heat resistance, and light resistance. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate. Polyester resins can be obtained, for example, from dicarboxylic acids and/or ester-forming derivatives thereof and diols.

Examples of the dicarboxylic acid and/or its ester-forming derivatives used in the above polyester resin include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and its ester-forming derivatives. In addition, the ester-forming derivatives referred to in the present invention are lower alkyl esters, acid anhydrides, acyl chlorides, and the like of dicarboxylic acids. Specifically, methyl esters, ethyl esters, hydroxyethyl esters, and the like are preferably used. A more preferable embodiment of the dicarboxylic acid and/or its ester-forming derivatives used in the present invention is terephthalic acid and/or its dimethyl ester.

Examples of diols used in the above polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and cyclohexanedimethanol. Among them, ethylene glycol is preferably used.

When using a polyamide resin as a resin for ultra-fine fibers, polyamide 6, polyamide 66, polyamide 56, polyamide 610, polyamide 11, polyamide 12, copolymerized polyamide, etc. can be used.

Resins used in ultrafine fibers may contain, depending on various purposes, inorganic particles such as titanium oxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents.

Additionally, it is desirable that the resin used in the ultrafine fibers contain components derived from biomass resources.

When a polyester resin is used as a resin for ultra-fine fibers, the biomass resource-derived component may be a dicarboxylic acid or an ester-forming derivative thereof, which is a constituent thereof, or a biomass resource-derived component may be used as a diol. However, from the viewpoint of reducing environmental load, it is preferable to use a biomass resource-derived component for both the dicarboxylic acid or an ester-forming derivative thereof and the diol.

When using polyamide resin as a resin for ultrafine fibers, as a component derived from biomass resources, polyamide 56, polyamide 610, and polyamide 11 are preferably used because raw materials derived from biomass resources can be obtained economically and from the viewpoint of fiber properties.

The cross-sectional shape of the ultrafine fiber may be either a circular cross-section or an irregular cross-section. Specific examples of irregular cross-sections include polygons such as ellipses, flat shapes, triangles, fan shapes, and cross shapes.

In the present invention, it is important that the average single fiber diameter of the ultrafine fibers is 0.1 µm or more and 10 µm or less. When the average single fiber diameter of the ultrafine fibers is 10 µm or less, preferably 7 µm or less, and more preferably 5 µm or less, the sheet-like product can be made more flexible. In addition, the quality of the hair growth can be improved. On the other hand, when the average single fiber diameter of the ultrafine fibers is 0.1 µm or more, preferably 0.3 µm or more, and more preferably 0.7 µm or more, the sheet-like product can have excellent color development after dyeing when dyeing. In addition, when performing a raising treatment by buffing, the ease of dispersing and handling of the ultrafine fibers present in a bundle shape can be improved.

The average single fiber diameter referred to in the present invention is measured by the following method. That is,

(1) A cross-section of the sheet-shaped object cut in the thickness direction is observed using a scanning electron microscope (SEM).

(2) The fiber diameters of 50 random ultra-fine fibers within the observation surface are measured in three directions for each ultra-fine fiber cross-section. However, when ultra-fine fibers with an irregular cross-section are employed, the cross-sectional area of a single fiber is first measured, and the diameter of the circle corresponding to the cross-sectional area is calculated using the following formula. The diameter thus obtained is used as the single fiber diameter of the single fiber.

ㆍSingle fiber diameter (㎛) = (4 × (cross-sectional area of single fiber (㎛ ² )) / π) ^1/2

(3) Calculate the arithmetic mean (㎛) of the total 150 points obtained and round it to the second decimal place.

[Fiber base]

The fibrous substrate used in the present invention comprises the above-described ultrafine fibers. Furthermore, the fibrous substrate may be mixed with ultrafine fibers of other raw materials.

As a specific form of the above-mentioned fibrous substrate, a nonwoven fabric formed by interlacing the individual ultrafine fibers or a nonwoven fabric formed by interlacing bundles of ultrafine fibers can be used. Among these, a nonwoven fabric formed by interlacing bundles of ultrafine fibers is preferably used from the viewpoint of the strength and texture of the sheet-like product. From the viewpoint of flexibility and texture, a nonwoven fabric in which the ultrafine fibers constituting the fiber bundles of ultrafine fibers are appropriately spaced apart from each other and have voids is particularly preferably used. A nonwoven fabric formed by interlacing bundles of ultrafine fibers can be obtained, for example, by interlacing ultrafine fiber-expressing fibers in advance and then expressing the ultrafine fibers. Furthermore, a nonwoven fabric in which the ultrafine fibers constituting the fiber bundles of ultrafine fibers are appropriately spaced apart from each other and have voids can be obtained, for example, by using a sea-island composite fiber that can create voids between island components by removing the sea component.

As the above nonwoven fabric, either a short-fiber nonwoven fabric or a long-fiber nonwoven fabric may be used, but from the viewpoint of the texture and quality of the sheet-shaped product, a short-fiber nonwoven fabric is more preferably used.

When using a short-fiber nonwoven fabric, the fiber length of the short fibers is preferably in the range of 25 mm to 90 mm. By setting the fiber length to 25 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more, it becomes easy to obtain a sheet-like product with excellent wear resistance through interlacing. Furthermore, by setting the fiber length to 90 mm or less, more preferably 80 mm or less, and even more preferably 70 mm or less, it becomes possible to obtain a sheet-like product with even better texture and quality.

In the present invention, when using a nonwoven fabric as the fibrous substrate, a woven or knitted fabric may be inserted, laminated, or lined within the nonwoven fabric for purposes such as improving strength. The average single fiber diameter of the fibers constituting such a woven or knitted fabric is more preferably 0.3 µm or more and 10 µm or less, to prevent damage during needle punching and maintain strength.

As fibers constituting the above fabric or knitted fabric, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polylactic acid, synthetic fibers such as polyamides such as 6-nylon or 66-nylon, regenerated fibers such as cellulose polymers, and natural fibers such as cotton or hemp can be used.

[Polymer elastomer]

In the sheet-shaped article of the present invention, examples of the polymer elastomer include water-dispersible silicone resin, water-dispersible acrylic resin, water-dispersible urethane resin, and copolymers thereof. Among these, water-dispersible polyurethane resin is preferably used in terms of texture.

As the water-dispersible polyurethane resin, a resin obtained by the reaction of a polymer polyol having a number average molecular weight of preferably 500 or more and 5,000 or less, an organic polyisocyanate, and a chain extender is preferably used. Furthermore, in order to enhance the stability of the water-dispersible polyurethane dispersion, it is preferable to use a hydrophilic group-containing active hydrogen component in combination. By setting the number average molecular weight of the polymer polyol to 500 or more, more preferably 1,500 or more, it is easy to prevent the texture from becoming hard. Furthermore, by setting the number average molecular weight to 5,000 or less, more preferably 4,000 or less, it is easy to maintain the strength of the polyurethane as a binder. Hereinafter, a case where a water-dispersible polyurethane resin is used as the polymer elastomer will be described.

(1) Each reactive component of water-dispersed polyurethane resin

First, each reactive component of the water-dispersed polyurethane resin is explained.

(1-1) High molecular weight polyol

In the sheet-shaped article of the present invention, the polymer elastomer contains polyetherdiol as a constituent component. The content of polyetherdiol in the polymer polyol is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more, of the entire polymer polyol. Specific examples of the polyetherdiol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, and copolymerized polyetherdiols obtained by combining them. In addition, in the present specification, "containing as a constituent component" means containing as a monomer component or oligomer component constituting the polymer elastomer. Polyetherdiol has a high degree of freedom of its ether bonds, so that it has a low glass transition temperature and weak cohesion, making it easy to obtain a polyurethane with excellent flexibility.

(1-2) Organic diisocyanate

The organic diisocyanate used in the present invention includes an aromatic diisocyanate having a carbon number of 6 to 20 (excluding carbons in the NCO group, the same applies hereinafter), an aliphatic diisocyanate having a carbon number of 2 to 18, an alicyclic diisocyanate having a carbon number of 4 to 15, an aromatic aliphatic diisocyanate having a carbon number of 8 to 15, modified forms of these diisocyanates (carbodiimide modified forms, urethane modified forms, uretdione modified forms, etc.), and mixtures of two or more thereof.

Specific examples of the aromatic diisocyanate having 6 to 20 carbon atoms include 1,3- and/or 1,4-phenylenediisocyanate, 2,4- and/or 2,6-tolylenediisocyanate, 2,4'- and/or 4,4'-diphenylmethanediisocyanate (hereinafter abbreviated as MDI), 4,4'-diisocyanatebiphenyl, 3,3'-dimethyl-4,4'-diisocyanatebiphenyl, 3,3'-dimethyl-4,4'-diisocyanatediphenylmethane, and 1,5-naphthylenediisocyanate.

Specific examples of the aliphatic diisocyanate having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanateethyl)carbonate, and 2-isocyanateethyl-2,6-diisocyanatohexaate.

Specific examples of the alicyclic diisocyanate having 4 to 15 carbon atoms include isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanateethyl)-4-cyclohexylene-1,2-dicarboxylate, and 2,5- and/or 2,6-norbornane diisocyanate.

Specific examples of the aromatic aliphatic diisocyanate having 8 to 15 carbon atoms include m- and/or p-xylylene diisocyanate, α,α,α',α'-tetramethylxylylene diisocyanate, and the like.

Among these, the preferred organic diisocyanate is an alicyclic diisocyanate. In addition, a particularly preferred organic diisocyanate is dicyclohexylmethane-4,4'-diisocyanate.

(1-3) Renewal system

Examples of the chain extender used in the present invention include water, low molecular weight diols such as “ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol,” alicyclic diols such as “1,4-bis(hydroxymethyl)cyclohexane,” aromatic diols such as “1,4-bis(hydroxyethyl)benzene,” aliphatic diamines such as “ethylenediamine,” alicyclic diamines such as “isophoronediamine,” aromatic diamines such as “4,4-diaminodiphenylmethane,” aromatic aliphatic diamines such as “xylenediamine,” alkanolamines such as “ethanolamine,” hydrazine, dihydrazides such as “adipic acid dihydrazide,” and mixtures of two or more thereof.

Among these, preferred extenders are water, low molecular weight diols, and aromatic diamines, and more preferred extenders include water, ethylene glycol, 1,4-butanediol, 4,4'-diaminodiphenylmethane, and mixtures of two or more thereof.

(2) Additives for water-dispersible polyurethane resin

In the present invention, for the reasons described below, it is important to add a monovalent cation-containing inorganic salt to a solution containing a water-dispersible polyurethane. In addition, various stabilizers such as a colorant such as titanium oxide, an ultraviolet absorber (benzophenone-based, benzotriazole-based, etc.), an antioxidant (hindered phenol such as 4,4-butylidenebis(3-methyl-6-1-butylphenol); an organic phosphite such as triphenylphosphite or trichloroethylphosphite), and an inorganic filler (calcium carbonate, etc.) can be contained as needed.

(3) Composition of water-dispersible polyurethane resin

In the water-dispersible polyurethane used in the present invention, as a component that makes the polyurethane contain a hydrophilic group, for example, a hydrophilic group-containing active hydrogen component can be mentioned. As the hydrophilic group-containing active hydrogen component, a compound containing a nonionic group, an anionic group, and/or a cationic group and an active hydrogen can be mentioned.

Examples of compounds having a nonionic group and active hydrogen include compounds containing two or more active hydrogen components or two or more isocyanate groups and having a polyoxyethylene glycol group having a molecular weight of 250 to 9,000 in the side chain, and triols such as trimethylolpropane or trimethylolbutane.

Examples of compounds having an anionic group and active hydrogen include carboxyl group-containing compounds such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid, and their derivatives; compounds containing sulfonic acid groups such as 1,3-phenylenediamine-4,6-disulfonic acid, and 3-(2,3-dihydroxypropoxy)-1-propanesulfonic acid, and their derivatives; and salts of these compounds neutralized with a neutralizing agent.

Examples of compounds containing cationic groups and active hydrogen include tertiary amino group-containing compounds such as 3-dimethylaminopropanol, N-methyldiethanolamine, N-propyldiethanolamine, and their derivatives.

The above hydrophilic group-containing active hydrogen component can also be used in the form of a salt neutralized with a neutralizing agent.

As for the active hydrogen component containing a hydrophilic group used in the polyurethane molecule, from the viewpoint of the mechanical strength and dispersion stability of the water-dispersible polyurethane resin, it is preferable to use 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and their neutralized salts.

In the present invention, a hydrophilic group in a polymer elastomer is a group having an active hydrogen. Specific examples of the hydrophilic group include a hydroxyl group, a carboxyl group, a sulfonic acid group, an amino group, and the like.

In the present invention, the polymer elastomer has an N-acylurea bond and/or an isourea bond within the polymer elastomer. Here, having an N-acylurea bond and/or an isourea bond within the polymer elastomer means that the polymer elastomer has an N-acylurea bond and/or an isourea bond. When a water-dispersible polyurethane resin is used as the polymer elastomer, the N-acylurea bond and/or the isourea bond can be formed, for example, by reacting a hydroxyl group and/or a carboxyl group present as the hydrophilic group-containing active hydrogen component described above with a carbodiimide-based crosslinking agent. As a result, a three-dimensional crosslinked structure by an N-acylurea bond and/or an isourea bond, which has excellent physical properties such as light resistance, heat resistance, and abrasion resistance, and flexibility, is imparted to the molecules of the polymer elastomer, thereby dramatically improving physical properties such as abrasion resistance while maintaining the flexibility of a sheet-shaped article.

In addition, the presence of the N-acylurea group or isourea group in the polymer elastomer can be analyzed by performing mapping processing (analyzing equipment, such as "TOF.SIMS 5" manufactured by ION-TOF Co., Ltd.) or infrared spectroscopy analysis (analyzing equipment, such as "FT/IR 4000 series" manufactured by Nippon Bunko Co., Ltd.) on the cross-section of the sheet-shaped material, for example.

The number average molecular weight of the polymer elastomer used in the present invention is preferably 20,000 or more from the viewpoint of resin strength, and further preferably 500,000 or less from the viewpoints of viscosity stability and workability. The number average molecular weight is more preferably 30,000 or more and 150,000 or less.

The number average molecular weight of the above polymer elastomer can be obtained by gel permeation chromatography and is measured, for example, under the following conditions.

Device: HLC-8220 manufactured by Tosoh Corporation

ㆍColumn: Dosoh TSKgel α-M

ㆍSolvent: N,N-dimethylformamide (DMF)

Temperature: 40℃

ㆍCorrection: Polystyrene

The polymer elastomer used in the present invention is preferably present inside the fibrous substrate from the viewpoint of appropriately holding fibers together in the sheet-shaped body and preferably having hairs on at least one side of the sheet-shaped body.

[Sheet shape]

It is important that the sheet-shaped article of the present invention has a longitudinal stiffness of 40 mm or more and 140 mm or less, as defined by Method A (45° cantilever method) described in JIS L 1096:2010 "Testing Methods for Raw Fabrics of Woven and Knitted Fabrics." By setting the stiffness within the above range, it is possible to have appropriate flexibility and resilience. Regarding the stiffness, it is preferably 50 mm or more, more preferably 55 mm or more, from the viewpoint of obtaining a sheet-shaped article with resilience, and it is preferably 120 mm or less, more preferably 110 mm or less, from the viewpoint of obtaining a flexible sheet-shaped article.

The longitudinal direction in the sheet-shaped article of the present invention refers to the direction in which the sheet-shaped article has been napped. The method for determining the direction in which the napping has been performed can be appropriately employed depending on the components of the sheet-shaped article, such as visual confirmation when tracing with a finger or SEM photography. That is, when tracing with a finger, the direction in which napped fibers can lie down or stand up is the longitudinal direction. In addition, when the surface of the sheet-shaped article traced with a finger is photographed with an SEM, the direction in which the napped fibers lie down the most is the longitudinal direction. On the other hand, the transverse direction in the sheet-shaped article of the present invention refers to the direction perpendicular to the longitudinal direction as the transverse direction.

In addition, it is important that the sheet-shaped article of the present invention has a wear loss of 25 mg or less in a Martindale abrasion test 20,000 times specified by JIS L 1096:2005 after a light fastness test measured under the conditions of a xenon arc amount of 110 MJ/㎡ of the JIS L 0843:2006 light fastness measurement method. By setting the wear loss after the light fastness test within the above range, it is possible to suppress deterioration of the polymer elastomer even when used for a long period of time in a harsh environment such as exposure to sunlight, thereby maintaining the appearance of the sheet-shaped article. From the viewpoint of suppressing deterioration of the appearance of the sheet-shaped article, the wear loss is preferably 23 mg or less, and more preferably 20 mg or less.

The sheet-shaped article of the present invention preferably has a wear loss of 20 mg or less in a Martindale abrasion test of 20,000 cycles as defined by JIS L 1096:2010 before a light fastness test. By setting the wear loss before the light fastness test within the above range, it becomes easier to suppress fluffing and deterioration of appearance during actual use. The wear loss is preferably 18 mg or less, and more preferably 15 mg or less, from the viewpoint of further suppressing fluffing during actual use.

The sheet-shaped article of the present invention preferably contains a polymer elastomer at 10% by mass or more. From the viewpoint of suppressing breakage due to tension in the manufacturing process or fluffing during actual use, it is more preferably contained at 12% by mass or more, and even more preferably contained at 15% by mass or more. The upper limit of the content is not particularly limited, but is usually 50% by mass or less, preferably 40% by mass or less, and more preferably 35% by mass or less.

It is further preferable that the sheet-shaped article of the present invention satisfies the following condition 3.

Condition 3: When the raised surface of the sheet-shaped material is loaded on a hot plate heated to 150°C and pressed with a pressing load of 2.5 kPa for 10 seconds, the L value retention rate (hereinafter, sometimes simply referred to as the L value retention rate) is 90% or more and 100% or less.

Among these, the L value retention rate is 90% or more, more preferably 92% or more, and even more preferably 95% or more, so that the sheet-shaped product has high heat resistance.

In addition, in the present invention, the "napped surface of the sheet-shaped object" refers to a surface of the sheet-shaped object that has undergone a napped treatment. In addition, the L value is the L value defined by the Commission International on Illumination (CIE), and the L value retention rate in the present invention is an index indicating the extent to which a sheet-shaped object with a small rate of change in brightness under heating and pressing conditions, that is, a dark color before heating and pressing, does not become brighter after heating and pressing.

In addition, in the present invention, the L value retention rate refers to a value calculated by measuring in the following order.

(1) Cut the sheet shape and measure the L value of the cut test piece using a colorimeter (e.g., “CR-410” manufactured by Konica Minolta Co., Ltd.).

(2) Place the test piece with the raised side facing down on a hot plate (e.g., “CHP-250DN” manufactured by Azwon Co., Ltd.) heated to 150°C.

(3) Load the indenter adjusted to a pressure load of 2.5 kPa on the test piece and maintain it for 10 seconds.

(4) Remove the indenter on the test piece, and measure the L value of the raised surface of the test piece using the colorimeter described above.

(5) The L value retention rate is calculated from the following equation.

L value retention rate (%) = (L value measured in (1)) / (L value measured in (4)) × 100

In order to make the wear reduction and L value retention rate before and after the light resistance test and the light resistance test within the above ranges, for example, a sheet-shaped article can be manufactured through a polymer elastomer impregnation process, an ultrafine fiber expression process, and a drying process, which will be described later. By performing the ultrafine fiber expression process after impregnating the polymer elastomer, a gap can be created between the ultrafine fibers and the polymer elastomer, making it easier to obtain a flexible texture. In addition, for example, by performing a heat treatment (curing treatment) at a temperature of 120°C or more and 180°C or less in the drying process, the particles of the polymer elastomer can be aggregated, making it easier to improve the light resistance, abrasion resistance, and heat resistance. In addition, by setting the thermal solidification temperature of the aqueous dispersion to the range described later, the uneven distribution (migration) of polyurethane to the surface of the sheet-shaped article due to moisture evaporation can be suppressed, thereby making it possible to increase the L value retention rate.

[Method for manufacturing sheet-shaped articles]

Next, a method for manufacturing a sheet-shaped article of the present invention will be described.

The method for manufacturing a sheet-shaped article of the present invention includes the following processes (1) to (4) in this order.

(1) A polymer elastomer impregnation process in which a fibrous substrate including an ultrafine fiber-forming fiber is impregnated with an aqueous dispersion containing a polymer elastomer, a monovalent cation-containing inorganic salt, and a crosslinking agent, and then heat-treated at a temperature of 120°C or more and 180°C or less, wherein the polymer elastomer has a hydrophilic group and further includes polyetherdiol as a constituent component, and the content of the monovalent cation-containing inorganic salt in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer elastomer.

(2) Ultrafine fiber expression process of treating the above ultrafine fiber expression type fiber with alkali and expressing ultrafine fiber.

(3) Drying process that performs heat treatment at a temperature of 120℃ or higher and 180℃ or lower

(4) A raising process in which at least one side of a sheet-shaped object is raised to form hair on the surface.

In the present invention, the term “unstitched sheet-shaped article” refers to a sheet-shaped article before being treated with a stinger obtained by a method including at least the steps (1) to (3) in this order.

In the present invention, it is preferable to use ultrafine fiber-expressing fibers as a means of obtaining ultrafine fibers. By interlacing ultrafine fiber-expressing fibers in advance to form a nonwoven fabric, and then performing ultrafine fiber refinement, a nonwoven fabric comprising bundles of ultrafine fibers interlaced can be obtained.

As an ultrafine fiber-forming fiber, a sea-island type composite fiber is used in which a thermoplastic resin of two components (two or three components in the case of core-sheath composite fibers with island fibers) having different solvent solubilities is used as a sea component and an island component, and the sea component is dissolved and removed using a solvent or the like to make the island component into ultrafine fibers. This is preferable from the viewpoint of the texture and surface quality of a sheet-shaped product because when the sea component is removed, an appropriate gap can be provided between the island components, i.e., between the ultrafine fibers within the fiber bundle.

As for the island-type composite fiber, a method using a island-type composite spinneret and a polymer mutual array that mutually aligns and spins two components of a sea component and an island component (three components when the island fiber is a core-sheath composite fiber) is preferable from the viewpoint that ultra-fine fibers with a uniform single fiber diameter can be obtained.

As the marine component of the sea-type composite fiber, polyethylene, polypropylene, polystyrene, copolymerized polyester copolymerized with sodium sulfoisophthalic acid or polyethylene glycol, and polylactic acid, etc. can be used, but from the viewpoints of thread manufacturability and ease of dissolution, polystyrene or copolymerized polyester are preferably used.

It is preferable to perform the dissolution removal of the marine component after the application of the polymer elastomer, as described below.

The mass ratio of the sea component and the island component in the sea-island composite fiber used in the present invention is preferably in the range of sea component:island component = 10:90 to 80:20. When the mass ratio of the sea component is 10 mass% or more, the sea component can be easily sufficiently fined. Furthermore, when the mass ratio of the sea component is 80 mass% or less, the ratio of the dissolved component is low, thereby improving productivity. The mass ratio of the sea component and the island component is more preferably in the range of sea component:island component = 20:80 to 70:30.

In addition, it is preferable that the fiber interlace body take the form of a nonwoven fabric, and as described above, it can be used as a short-fiber nonwoven fabric or a long-fiber nonwoven fabric. However, a short-fiber nonwoven fabric is preferable because the fibers that are oriented in the thickness direction of the fibrous substrate are greater than those of a long-fiber nonwoven fabric, and a high density can be obtained on the surface of the fibrous substrate when raised.

When using a single-fiber nonwoven fabric as a fiber interlacing body, the resulting ultra-fine fiber-like fiber is preferably crimped and cut to a predetermined length to obtain raw cotton. The crimping or cutting process can be performed using known methods.

Next, the obtained raw material is made into a fiber web using a cross lapper or the like and interlaced to obtain a short-fiber nonwoven fabric. Methods for obtaining a short-fiber nonwoven fabric by interlacing a fiber web include needle punching or water jet punching.

In addition, the obtained short-fiber nonwoven fabric and fabric are laminated and interlaced. The interlaced integration of the short-fiber nonwoven fabric and fabric can be achieved by laminating the fabric on one or both sides of the short-fiber nonwoven fabric, or by sandwiching the fabric between multiple short-fiber nonwoven webs, and then interlacing the fibers of the short-fiber nonwoven fabric and the fabric by needle punching or water jet punching.

The apparent density of the staple fiber nonwoven fabric comprising composite fibers (ultra-fine fiber-forming fibers) after needle punching or water jet punching is preferably 0.15 g/cm3 or more and 0.45 g/cm3 or less. By setting the apparent density to preferably 0.15 g/cm3 or more, the fibrous substrate can obtain sufficient dimensional stability and shape stability. On the other hand, by setting the apparent density to preferably 0.45 g/cm3 or less, sufficient space for imparting a polymeric elastic body can be maintained.

From the perspective of densification, the nonwoven fabric thus obtained is preferably contracted and densified by dry heat, wet heat, or both. Furthermore, the nonwoven fabric can be compressed in the thickness direction by calendering or the like.

The method for manufacturing a sheet-shaped article of the present invention comprises (1) a polymer elastomer impregnation step of impregnating a fibrous substrate including an ultrafine fiber-forming fiber with an aqueous dispersion containing a polymer elastomer, a monovalent cation-containing inorganic salt, and a crosslinking agent, and then performing a heat treatment at a temperature of 120°C or more and 180°C or less, wherein the polymer elastomer has a hydrophilic group and further includes polyetherdiol as a constituent component, and the content of the monovalent cation-containing inorganic salt in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer elastomer.

In the method for manufacturing a sheet-shaped article of the present invention, a polymer elastomer having a hydrophilic group and including polyetherdiol as a constituent is applied to a fibrous substrate. When a nonwoven fabric is used as the fibrous substrate, the application of the polymer elastomer can be performed to either a nonwoven fabric including composite fibers or a nonwoven fabric made into ultrafine fibers.

In the method for manufacturing a sheet-shaped article of the present invention, the polymer elastomer contains polyetherdiol as a constituent component. The reason is as described in the above-mentioned (1-1) section on polymer polyol.

In the method for manufacturing a sheet-shaped article of the present invention, the solidification after application of the polymer elastomer uses a dry heat solidification method in which heat treatment is performed at a temperature of 120°C or higher and 180°C or lower. In other solidification methods, for example, a hydrothermal solidification method in which the polymer elastomer is solidified in hot water, the polymer elastomer diffuses in the hot water and some of it falls off, which raises concerns about processability. Furthermore, in an acid solidification method in which the polymer elastomer is solidified with acid, it is necessary to neutralize the acid solution remaining in the sheet, which is not preferable in terms of processability. On the other hand, the dry heat solidification method applied in the present invention is a very simple method in which a sheet impregnated with the polymer elastomer is heat-treated in a hot air dryer or the like, and there is no concern about the polymer elastomer falling off, so it is a method with excellent processability.

In the method for producing a sheet-shaped article of the present invention, the heating temperature for dry heat solidification is 120°C or higher and 180°C or lower. A heating temperature of 140°C or higher is more preferable. This is because the polymer elastomer can be rapidly solidified and the uneven distribution of the polymer elastomer toward the lower surface of the sheet due to its own weight can be suppressed. Furthermore, although the present invention requires combined use with a crosslinking agent, setting the temperature to the above allows the crosslinking reaction to be sufficiently promoted, forming a three-dimensional meshwork structure and improving physical properties, light resistance, and heat resistance. A heating temperature of 175°C or lower is more preferable. This is because the thermal degradation of the polymer elastomer can be suppressed.

The concentration of the polymer elastomer in the aqueous dispersion (content of the polymer elastomer in 100 mass% of the aqueous dispersion) is preferably 10 mass% or more and 50 mass% or less, and more preferably 15 mass% or more and 40 mass% or less, from the viewpoint of storage stability of the aqueous dispersion.

The aqueous dispersion used in the present invention may contain 40 mass% or less of a water-soluble organic solvent per 100 mass% of the aqueous dispersion in order to improve storage stability or film-forming properties, but from the viewpoint of preserving the film-forming environment, etc., it is preferable that the content of the organic solvent be 1 mass% or less.

In the method for producing a sheet-shaped article of the present invention, a monovalent cation-containing inorganic salt is contained in the aqueous dispersion. By containing the monovalent cation-containing inorganic salt, heat-sensitive coagulability can be imparted to the aqueous dispersion. In the present invention, heat-sensitive coagulability refers to a property in which, when the aqueous dispersion is heated and reaches a certain temperature (thermal coagulation temperature), the fluidity of the aqueous dispersion decreases and coagulation occurs.

In the method for manufacturing a sheet-shaped article of the present invention, after applying an aqueous dispersion to a fibrous substrate, heat treatment is performed at a temperature of 120°C or higher and 180°C or lower, and dry heat coagulation is performed to apply a polymer elastic body to the fibrous substrate.

If the polymer elastomer does not possess thermosetting properties, migration occurs, in which the polymer elastomer migrates to the sheet surface as moisture evaporates. Furthermore, as the polymer elastomer solidifies, it becomes unevenly distributed around the fibers, forming a structure in which the polymer elastomer covers the fibers and strongly restricts their movement. This significantly hardens the texture of the sheet.

The thermal coagulation temperature of the aqueous dispersion is preferably 55°C or higher and 80°C or lower. The thermal coagulation temperature is more preferably 60°C or higher because the stability of the aqueous dispersion during storage is improved and adhesion of the polymer elastomer to the machine during operation can be suppressed. The migration phenomenon of the polymer elastomer to the surface layer of the fibrous substrate can be suppressed, and further, since the coagulation of the polymer elastomer progresses before moisture evaporates from the fibrous substrate, a structure similar to that obtained by wet coagulation of a solvent-based polymer elastomer, that is, a structure in which the polymer elastomer does not strongly bind the fibers, can be formed, and good flexibility and resilience can be achieved. Therefore, the thermal coagulation temperature is more preferably 70°C or lower.

In the present invention, it is important to use a monovalent cation-containing inorganic salt as the thermal coagulant. The monovalent cation-containing inorganic salt is preferably sodium chloride and/or sodium sulfate. In conventional methods, inorganic salts having divalent cations, such as magnesium sulfate or calcium chloride, have been suitably used as thermal coagulants. However, these inorganic salts significantly affect the stability of the aqueous dispersion even when added in small amounts. Therefore, depending on the polymer elastomer type, it is difficult to strictly control the thermal gelation temperature by adjusting the amount added. In addition, there have been problems such as concerns about gelation during the preparation or storage of the aqueous dispersion. On the other hand, monovalent cation-containing inorganic salts with small ionic valences have a small effect on the stability of the aqueous dispersion. Therefore, by adjusting the amount added, the thermal coagulation temperature can be strictly controlled while ensuring the stability of the aqueous dispersion.

Furthermore, in the present invention, it is important that the content of the monovalent cation-containing inorganic salt in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the polymer elastomer. By setting the content to 10 parts by mass or more, the ions present in large quantities in the aqueous dispersion uniformly act on the polymer elastomer particles, thereby rapidly completing coagulation at a specific thermal coagulation temperature. As a result, a more remarkable effect can be obtained when coagulating the polymer elastomer in a state where a large amount of moisture is contained in the fibrous substrate as described above. As a result, it is possible to form a structure very similar to that obtained by wet coagulation of a solvent-based polymer elastomer, and to achieve good flexibility and resilience. Furthermore, by setting the addition amount as described above, the inorganic salt acts as an inhibitor in the fusion of the polymer elastomer particles, and can also suppress hardening of the polymer elastomer by forming a continuous film. Meanwhile, by limiting the content to 50 parts by mass or less, a continuous film structure of an appropriate polymer elastomer can be preserved, thereby suppressing deterioration of physical properties. Furthermore, the stability of the aqueous dispersion can be maintained.

In the method for manufacturing a sheet-shaped article of the present invention, it is important to include a cross-linking agent in the aqueous dispersion. By introducing a three-dimensional network structure into the polymer elastomer by the cross-linking agent, physical properties such as wear resistance can be improved. Furthermore, by using the aforementioned monovalent cation-containing inorganic salt in combination, the coagulation of the polymer elastomer and the reaction between the polymer elastomer and the cross-linking agent can proceed simultaneously, thereby forming a dense three-dimensional network structure and controlling the adhesive structure of the fibers, thereby making the sheet-shaped article flexible, and at the same time, achieving high physical properties, high light resistance, and high heat resistance of the sheet-shaped article. In other words, in order to improve the physical properties, light resistance, and heat resistance of the sheet-shaped article, the combined use of the monovalent cation-containing inorganic salt, the cross-linking agent, and control of the heating temperature during dry heat coagulation is essential.

Since the polymer elastomer obtained after the reaction has excellent light resistance, heat resistance, and wear resistance, and also has good flexibility, it is preferable that the crosslinking agent is a carbodiimide-based crosslinking agent.

The method for manufacturing a sheet-shaped article of the present invention includes (2) an ultrafine fiber expression step of alkali-treating ultrafine fiber-expressing fibers and expressing ultrafine fibers. By performing the alkali treatment after applying the polymer elastomer, voids are created between the polymer elastomer and the ultrafine fibers due to components dissolved by the alkali treatment, so that the ultrafine fibers are not directly gripped by the polymer elastomer, and the texture of the sheet-shaped article becomes more flexible.

When using a sea-island composite fiber as an ultrafine fiber-forming fiber, the fiber ultrafine treatment (seaweed removal treatment) can be performed, for example, by immersing the sea-island composite fiber in a solvent and then extracting the solution. Examples of solvents that dissolve seaweed components include an alkaline solution such as sodium hydroxide or hot water.

In the ultrafine fiber expression process, devices such as a continuous dyeing machine, a vibro-washer type de-staining machine, a liquid dyeing machine, a winch dyeing machine, and a jigger dyeing machine can be used.

After the ultrafine fiber expression process, it is desirable to perform a thorough cleaning process after alkaline treatment. This cleaning process allows processing without leaving residual alkali or monovalent cation-containing inorganic salts attached to the sheet-shaped material, and without affecting production equipment. For environmental and safety reasons, water is preferred as the cleaning solution.

The method for manufacturing a sheet-shaped article of the present invention includes (3) a drying step of performing a heat treatment at a temperature of 120°C or more and 180°C or less. In the ultra-fine fiber expression step, the bonds of the polymer elastomer are partially decomposed by a solvent that dissolves components other than the ultra-fine fibers in the ultra-fine fiber expression type fiber. Therefore, by performing a curing treatment by drying, the particles of the polymer elastomer are coagulated, thereby further improving physical properties such as light resistance, wear resistance, and heat resistance.

In the method for manufacturing a sheet-shaped article of the present invention, the heating temperature in the curing treatment by drying is 120°C or higher and 180°C or lower. In order to enhance the effect of the curing treatment and to improve properties such as light resistance, wear resistance, and heat resistance, the heating temperature is preferably 140°C or higher, more preferably 150°C or higher. In order to suppress thermal deterioration of the polymer elastomer, the heating temperature is preferably 175°C or lower, more preferably 170°C or lower.

The method for manufacturing a sheet-shaped article of the present invention preferably includes a dyeing step for dyeing the unbrushed sheet-shaped article or sheet-shaped article after the drying step. Various methods commonly used in the art can be employed for this dyeing treatment, and examples thereof include a liquid dyeing treatment using a jigger dyeing machine or a liquid dyeing machine, an immersion dyeing treatment such as a thermosol dyeing treatment using a continuous dyeing machine, or a dyeing treatment on a raised surface using roller dyeing, screen dyeing, inkjet dyeing, sublimation dyeing, and vacuum sublimation dyeing. Among these, a liquid dyeing machine is preferably used because a softening effect can be imparted to the unbrushed sheet-shaped article or sheet-shaped article simultaneously with dyeing, thereby making the unbrushed sheet-shaped article or sheet-shaped article flexible. In addition, various resin finishing processes can be performed after dyeing, if necessary.

The dyeing temperature varies depending on the type of fiber, but is preferably between 80°C and 150°C. Setting the dyeing temperature to 80°C or higher, or more preferably 110°C or higher, facilitates efficient dyeing of the fiber. Meanwhile, setting the dyeing temperature to 150°C or lower, or more preferably 130°C or lower, prevents deterioration of the polymer elastomer.

The dye used in the present invention may be selected in accordance with the type of fiber constituting the fibrous substrate, and is not particularly limited. For example, disperse dyes may be used for polyester fibers, and acid dyes or gold-containing dyes may be used for polyamide fibers, or combinations thereof. In the case of dyeing with disperse dyes, reduction washing may be performed after dyeing.

The use of dyeing agents during dyeing is also desirable. Using dyeing agents can improve the uniformity and reproducibility of the dyeing process. Furthermore, after dyeing, or during the same bath or after dyeing, finishing treatments using, for example, silicone softeners, antistatic agents, water repellents, flame retardants, light-resistant agents, and antibacterial agents can be applied.

In the present invention, regardless of before or after the dyeing process, it is also preferable to cut in half in the thickness direction from the viewpoint of manufacturing efficiency.

The method for manufacturing a sheet-shaped article of the present invention includes (4) a napping process in which at least one surface of a non-napped sheet-shaped article is napped to form naps on the surface, regardless of whether the napping process is performed before or after the dyeing process. The method for forming naps is not particularly limited, and various methods commonly used in the art, such as buffing with sandpaper or the like, can be used. If the nap length is too short, it is difficult to obtain an elegant appearance, and if it is too long, pilling tends to occur easily. Therefore, the nap length is preferably 0.2 mm or more and 1.0 mm or less.

In addition, in one embodiment of the present invention, a lubricant such as silicone may be applied to the non-brushed sheet-shaped object prior to the brushing treatment. Applying the lubricant facilitates brushing by surface grinding, resulting in a very good surface finish, which is preferable. Furthermore, an antistatic agent may be applied prior to the brushing treatment. Applying the antistatic agent is preferable because it makes it difficult for grinding dust generated from the sheet-shaped object during grinding to be deposited on the sandpaper.

Additionally, in one aspect of the present invention, the surface may be subjected to a design treatment as needed. For example, subsequent processing such as perforation, embossing, laser processing, pin sonic processing, and printing processing may be performed.

Example

Next, the sheet-shaped article of the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[Evaluation Method]

(1) Average single fiber diameter of sheet-shaped material:

A cross-section perpendicular to the thickness direction including the fibers of the sheet-shaped material was observed at 3000 times using a scanning electron microscope (SEM, Keyence Co., Ltd., VE-7800 type), and the diameters of 50 single fibers randomly selected within a field of view of 30 μm × 30 μm were measured in μm units to the first decimal place.

This was performed in three locations, and the diameters of a total of 150 single fibers were measured, and the average value was calculated to one decimal place. If fibers with a diameter exceeding 50㎛ were mixed, the fibers were excluded from the measurement of the average fiber diameter as they were not considered ultra-fine fibers. In addition, if the ultra-fine fibers had an irregular cross-section, as described above, the cross-sectional area of the single fibers was first measured, and the diameter was calculated assuming that the cross-section was circular, thereby obtaining the diameter of the single fibers. The average value using this as the population was calculated, and this was used as the average single fiber diameter.

(2) Coagulation temperature of aqueous dispersion

In each example and comparative example, 20 g of an aqueous dispersion containing a polymer elastomer was prepared, placed in a test tube having an inner diameter of 12 mm, a thermometer was inserted so that its tip was below the liquid surface, the test tube was sealed, and the test tube was immersed in a warm water bath at a temperature of 95°C so that the liquid surface of the aqueous dispersion was below the liquid surface of the warm water bath. While checking the temperature rise inside the test tube with the thermometer, the test tube was appropriately raised for a time of no more than 5 seconds at a time and shaken to a degree that allowed checking the presence or absence of liquid surface fluidity of the aqueous dispersion, and the temperature at which the liquid surface of the aqueous dispersion lost fluidity was defined as the solidification temperature. This measurement was performed three times for each type of aqueous dispersion, and the average value was calculated.

(3) Flexibility evaluation of sheet shapes:

Based on the A method (45° cantilever method) described in 8.21.1 of 8.21 “Strength” of JIS L 1096:2010 “Test method for raw fabric of woven and knitted fabrics”, five 2×15 cm test pieces were made in the longitudinal direction, placed on a horizontal stand having an inclined plane at an angle of 45°, and the test pieces were slid to read the scale when the center point of one end of the test piece came into contact with the inclined plane, and the average value of the five pieces was obtained.

(4) Wear evaluation of sheet-shaped objects

Abrasion evaluation was conducted based on JIS L 1096:2010. A Martindale abrasion tester, Model 406 manufactured by James H. Heal & Co., was used, and ABRASTIVE CLOTH SM25 from the same company was used as a standard friction cloth. A load of 12 kPa was applied to the sheet-shaped specimen before and after the light resistance test described below, and the number of abrasions was 20,000. The mass of the sheet-shaped specimen before and after abrasion was used to calculate the wear loss using the following formula.

Wear loss (mg) = Mass before wear (mg) - Mass after wear (mg)

Additionally, the wear reduction was calculated by rounding the value to the first decimal place.

(5) Light resistance test of sheet-shaped objects

The irradiation was conducted under conditions in which the measurement time was adjusted so that the xenon arc irradiation dose was 110 MJ/㎡ in accordance with the JIS L 0843:2006 light fastness measurement method (Method B, Exposure Method 5).

(6) Identification of bound species in polymer elastomers

For the polymer elastomer separated from the above sheet-shaped material, the bound species were identified by infrared spectroscopy analysis using the FT/IR 4000 series manufactured by Nippon Bunko Co., Ltd.

(7) L value retention rate

As a hot plate, "CHP-250DN" manufactured by Azwon Co., Ltd. was used, and as a colorimeter, "CR-410" manufactured by Konica Minolta Co., Ltd. was used, and measurement and calculation were performed by the above-described method.

(8) Measurement of inorganic salts and their contents included in sheet-shaped materials:

The sheet-shaped article was immersed in N,N-dimethylformamide overnight, and the solution from which the polymer elastomer and inorganic salt were eluted was concentrated by heat drying at 140°C and solidified. Distilled water was added to the obtained solid, and only the inorganic salt was eluted. After the aqueous solution containing the inorganic salt was heat-dried, the amount of the inorganic salt contained in the sheet-shaped article was measured. In addition, the mass of the solidified polymer elastomer was also measured after heat drying, and the mass of the inorganic salt was calculated relative to the mass of the polymer elastomer. However, from the viewpoint of numerical validity, less than 0.1 mass% relative to the polymer elastomer is considered to be below the lower detection limit.

As for the type of inorganic salt, the aqueous solution containing the above inorganic salt was identified using an ion chromatograph device of the “ICS-3000 type” manufactured by Dionex.

[Method for manufacturing nonwoven fabric A for fibrous substrate]

A sea-island composite fiber was obtained using SSIA (sodium 5-sulfoisophthalate) 8 mol% copolymerized polyester as the sea component and polyethylene terephthalate as the island component, with a composite ratio of 20 mass% of the sea component and 80 mass% of the island component, with the number of islands being 16 islands/1 filament and the average single fiber diameter being 20 μm. The obtained sea-island composite fiber was cut to a fiber length of 51 mm, stapled, and formed into a fiber web through a card and a cross lapper, and a nonwoven fabric having a weight per unit area of 700 g/m2 and a thickness of 3.0 mm was manufactured by needle punching. The nonwoven fabric thus obtained was shrunk by immersing it in water at a temperature of 98°C for 2 minutes, and dried at a temperature of 100°C for 5 minutes, thereby obtaining nonwoven fabric A for a fibrous substrate.

[Method for manufacturing nonwoven fabric B for fibrous substrate]

An island-in-the-sea composite fiber was obtained using SSIA (sodium 5-sulfoisophthalate) 8 mol% copolymerized polyester as the sea component and polyethylene terephthalate as the island component, with a composite ratio of 43 mass% of the sea component and 57 mass% of the island component, with the number of islands being 16 islands/1 filament and the average single fiber diameter being 20 ㎛. The obtained island-in-the-sea composite fiber was cut to a fiber length of 51 mm, stapled, and formed into a fiber web through a card and a cross lapper, and a nonwoven fabric having a weight per unit area of 550 g/㎡ and a thickness of 2.9 mm was manufactured by needle punching. The nonwoven fabric thus obtained was shrunk by immersing it in water at a temperature of 98°C for 2 minutes, and dried at a temperature of 100°C for 5 minutes, thereby obtaining nonwoven fabric B for a fibrous substrate.

[Method for producing polymer elastomers]

A prepolymer was prepared in toluene solvent using polytetramethylene ether glycol (PTMG in the table) with a number average molecular weight (Mn) of 2,000 as the polyol, MDI as the isocyanate, and 2,2-dimethylolpropionic acid as the hydrophilic group-containing component. Ethylene glycol and ethylenediamine as chain extenders, polyoxyethylene nonylphenyl ether and water as external emulsifiers were added, and stirred. Toluene was removed by depressurization to obtain an aqueous dispersion of a polymer elastomer.

[Example 1]

(Non-woven fabric)

Nonwoven fabric A was used as a fibrous substrate as a nonwoven fabric.

(Granting of polymer elastomers)

For 100 parts by mass of a polymer elastomer, 20 parts by mass of sodium sulfate (indicated as “Na ₂ SO ₄ ” in Table 1) as a thermal coagulant was added, 3 parts by mass of a carbodiimide-based crosslinking agent was added, and the total solid content was adjusted to 12% by mass with water to obtain an aqueous dispersion containing a polymer elastomer. The thermal coagulation temperature was 70°C. The obtained nonwoven fabric A for fibrous substrate was immersed in the aqueous dispersion, and then dried for 20 minutes with hot air at a temperature of 160°C, thereby obtaining a polymer elastomer-impregnated nonwoven fabric having a thickness of 2.10 mm, to which a polymer elastomer was impregnated so that the polymer elastomer was impregnated to 20% by mass of 100% by mass of the sheet-shaped product when formed into a sheet-shaped product.

(ultra-fine fiber expression treatment)

The obtained polymer elasticity-imparted nonwoven fabric was immersed in an 8 g/L sodium hydroxide aqueous solution heated to 95°C and treated for 5 minutes to remove the marine component of the island-type composite fiber. Thereafter, the sodium hydroxide aqueous solution attached to the nonwoven fabric was immersed in water to wash for 30 minutes, and dried in a dryer at 160°C for 30 minutes to obtain a sheet (polymer elasticity-imparted sheet) containing ultrafine fibers.

(Dyeing/Finishing)

The obtained polymer elastic sheet after debonding was vertically cut in half in the thickness direction, and the opposite side of the half-cut surface was ground with endless sandpaper of sandpaper number 180, thereby obtaining a sheet-shaped article having a grain size of 0.75 mm.

The obtained sheet-shaped article having the obtained nap was dyed with a black dye using a liquid dyeing machine under temperature conditions of 120℃. Subsequently, drying was performed with a dryer, and a sheet-shaped article having an average single fiber diameter of 4.4㎛ of ultrafine fibers was obtained. The obtained sheet-shaped article had a strength of 80㎜, a wear loss before a light fastness test of 7㎎, and a wear loss after a light fastness test of 9㎎, and had a flexible texture and excellent light fastness and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 93%, and it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower limit of detection.

[Example 2]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

The heat-sensitive coagulant was changed to sodium chloride (indicated as "NaCl" in Table 1). In addition, the amount of heat-sensitive coagulant added, the heating temperature by hot air, and the amount of polymer elastic body provided were changed, and the same procedure as Example 1 was followed to obtain a polymer elastic body-provided nonwoven fabric.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 90 mm, the wear loss before the light resistance test was 6 mg, and the wear loss after the light resistance test was 8 mg. It had a flexible texture and excellent light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 91%, it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Example 3]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A nonwoven fabric imparted with polymer elasticity was obtained by performing the same procedure as in Example 1, except that the amount of added heat-sensitive coagulant, the heating temperature by hot air, and the amount of polymer elasticity were changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 55 mm, the wear loss before the light resistance test was 12 mg, and the wear loss after the light resistance test was 18 mg. It had a flexible texture and excellent light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 97%, it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower detection limit.

[Example 4]

(Non-woven fabric)

Nonwoven fabric B was used as a fibrous substrate as a nonwoven fabric.

(Granting of polymer elastomers)

Except for changing the heating temperature by hot air and the amount of polymer elastomer applied, the same procedure as in Example 2 was performed, and a polymer elastomer-applied nonwoven fabric having a thickness of 2.05 mm was obtained.

(ultra-fine fiber expression treatment)

The obtained polymer elastic body-imparted nonwoven fabric was immersed in an 8 g/L sodium hydroxide aqueous solution heated to 95°C and treated for 10 minutes to remove the marine component of the island-type composite fiber. Thereafter, the sodium hydroxide aqueous solution attached to the nonwoven fabric was immersed in water to wash for 30 minutes, and dried in a dryer at 170°C for 30 minutes to obtain a sheet (polymer elastic body-imparted sheet) containing ultrafine fibers.

(Dyeing/Finishing)

The obtained polymer elastic sheet after debonding was cut in half perpendicular to the thickness direction, and the opposite side of the half-cut surface was ground with endless sandpaper of sandpaper number 120, thereby obtaining a sheet-shaped article having a grain size of 0.75 mm.

The obtained sheet-shaped article having the obtained nap was dyed with a black dye using a liquid dyeing machine under temperature conditions of 120℃. Subsequently, drying was performed with a dryer, and a sheet-shaped article having an average single fiber diameter of 3.0㎛ of ultrafine fibers was obtained. The obtained sheet-shaped article had a stiffness of 75㎜, a wear loss before a light fastness test of 7㎎, and a wear loss after a light fastness test of 10㎎, and had a flexible texture and excellent light fastness and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 96%, and it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower limit of detection.

[Example 5]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A nonwoven fabric imparted with polymer elastomer was obtained in the same manner as in Example 1, except that the amount of the thermal coagulant and the amount of the thermal coagulant added were changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The obtained sheet-shaped body had a tensile strength of 100 mm, a wear loss of 6 mg before the light resistance test, and a wear loss of 8 mg after the light resistance test, and had a flexible texture and excellent light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 94%, and it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Example 6]

(Non-woven fabric)

As in Example 4, nonwoven fabric B for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

The same procedure as in Example 4 was followed to obtain a polymer elastic nonwoven fabric.

(ultra-fine fiber expression treatment)

The same procedure as in Example 4 was followed.

(Dyeing/Finishing)

By grinding the obtained polymer elastic sheet after debonding with endless sandpaper of sandpaper number 180 on both sides, a sheet-shaped article having a grain thickness of 1.50 mm was obtained.

The sheet-shaped article having the obtained hair was dyed using a black dye at a temperature of 120°C using a liquid dyeing machine. Subsequently, after drying using a dryer, the article was cut in half perpendicular to the thickness direction, thereby obtaining a sheet-shaped article having an average single fiber diameter of ultrafine fibers of 3.0 μm.

The obtained sheet-shaped body had a tensile strength of 80 mm, a wear loss of 6 mg before the light resistance test, and a wear loss of 9 mg after the light resistance test, and had a flexible texture and excellent light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. In addition, the L value retention rate was 96%, and it had excellent heat resistance, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Comparative Example 1]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

To 100 parts by mass of a polymer elastomer, 10 parts by mass of magnesium sulfate (indicated as "MgSO ₄ " in Table 1) as a heat-sensitive coagulant was added, 3 parts by mass of a carbodiimide-based cross-linking agent was added, and the total solid content was adjusted to 12% by mass with water to obtain an aqueous dispersion containing the polymer elastomer. However, gelation occurred on the surface of the nonwoven fabric during processing, and the polymer elastomer could not be applied to the nonwoven fabric.

[Comparative Example 2]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A polymer elastic nonwoven fabric was obtained by performing the same procedure as in Example 1 except that the amount of added thermal coagulant was changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was not measurable because it exceeded 150 mm, and it had a hard texture. The wear loss before the light resistance test was 15 mg, and the wear loss after the light resistance test was 25 mg. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 87%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower detection limit.

[Comparative Example 3]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A polymer elastic nonwoven fabric was obtained by performing the same procedure as in Example 1 except that the amount of added thermal coagulant was changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was not measurable because it exceeded 150 mm, and it had a hard texture. The wear loss before the light resistance test was 16 mg, and the wear loss after the light resistance test was 28 mg, indicating poor light resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 89%, the heat resistance was not sufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was below the lower detection limit.

[Comparative Example 4]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A nonwoven fabric imparted with polymer elasticity was obtained by performing the same procedure as in Example 2 except that no cross-linking agent was added.

(ultra-fine fiber expression treatment)

The same procedure as in Example 2 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was not measurable because it exceeded 150 mm, and it had a hard texture. The wear loss before the light resistance test was 21 mg, and the wear loss after the light resistance test was 32 mg, indicating poor light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds did not exist inside the polymer elastomer. In addition, the L value retention rate was 88%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower detection limit.

[Comparative Example 5]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A polymer elastic nonwoven fabric was obtained by performing the same procedure as in Example 1 except that the heating temperature was changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 120 mm, the wear loss before the light resistance test was 13 mg, and the wear loss after the light resistance test was 29 mg, indicating poor light resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 88%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Comparative Example 6]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

The same procedure as in Example 1 was followed to obtain a polymer elastic nonwoven fabric.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 130 mm, the wear loss before the light resistance test was 16 mg, and the wear loss after the light resistance test was 30 mg, indicating poor light resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 88%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Comparative Example 7]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

To 100 parts by mass of a polymer elastomer, 3 parts by mass of a carbodiimide-based crosslinking agent was added, and a nonionic thickener (guar gum) ["Neo Soft G" manufactured by Taiyo Chemical Co., Ltd.] was added so that the active ingredient amount was 1 part by mass per 100 parts by mass of the polymer elastomer, and the total solid content was adjusted to 13% by mass with water to obtain an aqueous dispersion containing the polymer elastomer. The obtained nonwoven fabric was immersed in the aqueous dispersion, and then treated in hot water at a temperature of 90°C for 3 minutes, and then dried with hot air at a drying temperature of 160°C for 30 minutes, so that when formed into a sheet, the polymer elastomer was imparted to 20% by mass of the polymer elastomer in 100% by mass of the sheet, and a polymer elastomer-imparted nonwoven fabric having a thickness of 2.10 mm was obtained.

(ultra-fine fiber expression treatment)

The same procedure as Example 1 was followed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 90 mm, the wear loss before the light resistance test was 20 mg, and the wear loss after the light resistance test was 33 mg, indicating poor light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 87%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

[Comparative Example 8]

(Non-woven fabric)

As in Example 1, nonwoven fabric A for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A nonwoven fabric imparted with polymer elasticity was obtained by performing the same procedure as in Example 2 except that no cross-linking agent was added.

(ultra-fine fiber expression treatment)

The obtained polymer elastic body-imparting nonwoven fabric was immersed in an 8 g/L sodium hydroxide aqueous solution heated to 95°C and treated for 5 minutes to remove the marine component of the island-type composite fibers. Next, the sodium hydroxide aqueous solution attached to the nonwoven fabric was immersed in water to wash for 30 minutes and dried in a dryer at 120°C for 30 minutes. Thereafter, water was added to the carbodiimide-based cross-linking agent, and the cross-linking agent prepared at a total solid content of 2 mass% was impregnated and applied to the sheet, and dried in a dryer at 160°C for 30 minutes to obtain a sheet containing ultrafine fibers (polymer elastic body-imparting sheet).

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was not measurable because it exceeded 150 mm, and it had a hard texture. The wear loss before the light resistance test was 20 mg, and the wear loss after the light resistance test was 30 mg, indicating poor light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 86%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was below the lower detection limit.

[Comparative Example 9]

(Non-woven fabric)

As in Example 4, nonwoven fabric B for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

The above nonwoven fabric was impregnated with a 10% by mass aqueous solution of PVA (NM-14 manufactured by Nippon Gosei Chemical Co., Ltd.) having a saponification degree of 99% and a polymerization degree of 1400, and dried by heating at a temperature of 140°C for 10 minutes to obtain a PVA-coated sheet having an adhesion amount of 30 parts by mass of PVA per 100 parts by mass of fibers of the nonwoven fabric for a fibrous substrate.

The obtained PVA-coated sheet was immersed in an 8 g/L sodium hydroxide aqueous solution heated to 95°C and treated for 30 minutes, thereby obtaining a sheet (PVA-coated ultrafine fiber nonwoven fabric) containing ultrafine fibers from which the sea component of the sea-type composite fibers was removed.

For 100 parts by mass of a polymer elastomer, 15 parts by mass of sodium chloride (indicated as “NaCl” in Table 1) as a heat-sensitive coagulant was added, 3 parts by mass of a carbodiimide-based crosslinking agent was added, and the total solid content was adjusted to 12% by mass with water to obtain an aqueous dispersion containing the polymer elastomer. The heat-sensitive coagulation temperature was 68°C. The obtained nonwoven fabric A for fibrous substrate was immersed in the aqueous dispersion, and then dried for 20 minutes with hot air at a temperature of 160°C, thereby obtaining a polymer elastomer-imparted sheet having a thickness of 2.05 mm, to which the polymer elastomer was imparted so that the polymer elastomer was 38% by mass among 100% by mass of the sheet when formed into a sheet.

The obtained polymer elastic body-imparting sheet was immersed in water heated to 95°C, treated for 10 minutes, and dried in a dryer at 120°C for 30 minutes, thereby obtaining a sheet from which the imparted PVA was removed.

(Dyeing/Finishing)

The same procedure as in Example 1 was followed. The strength of the obtained sheet-shaped body was 90 mm, the wear loss before the light resistance test was 11 mg, and the wear loss after the light resistance test was 26 mg, indicating poor light resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 91%, indicating excellent heat resistance, and the amount of monovalent cation-containing inorganic salt inside the polymer elastomer was 1.2 mass%.

[Comparative Example 10]

(Non-woven fabric)

As in Example 6, nonwoven fabric B for the fibrous substrate was used as a nonwoven fabric.

(Granting of polymer elastomers)

A polymer elastic nonwoven fabric was obtained by performing the same procedure as in Example 6 except that the heating temperature was changed.

(ultra-fine fiber expression treatment)

The same procedure as Example 6 was followed except that the drying temperature was changed.

(Dyeing/Finishing)

The same procedure as in Example 6 was followed. The strength of the obtained sheet-shaped body was 85 mm, the wear loss before the light resistance test was 21 mg, and the wear loss after the light resistance test was 31 mg, indicating poor light resistance and wear resistance. In addition, N-acylurea bonds and isourea bonds were present inside the polymer elastomer. In addition, the L value retention rate was 85%, the heat resistance was not sufficient, and the amount of monovalent cation-containing inorganic salts inside the polymer elastomer was below the lower detection limit.

Additionally, “PU” in Table 2 represents polyurethane.

The sheet-shaped article obtained by the present invention can be suitably used as an interior material having a very elegant appearance as a surface material for seats, ceilings and interiors of vehicles such as furniture, chairs and wall materials, automobiles, trains and aircrafts, uppers and trims of shoes such as shirts, jackets, casual shoes, sports shoes, men's shoes and women's shoes, bags, belts, wallets and parts thereof, and industrial materials such as wiping cloths, polishing cloths and CD curtains.

Claims (8)

A sheet-shaped article containing a polymer elastomer in a fibrous substrate, wherein the fibrous substrate includes ultrafine fibers having an average single fiber diameter of 0.1 µm or more and 10 µm or less, the polymer elastomer has a hydrophilic group, and further includes polyetherdiol as a constituent component, and has an N-acylurea bond and/or an isourea bond inside the polymer elastomer, and satisfies the following conditions 1 and 2.
Condition 1: The longitudinal strength specified by Method A (45° cantilever method) described in JIS L 1096:2010 “Testing method for raw fabrics of woven and knitted fabrics” is 50 mm or more and 140 mm or less.
Condition 2: The wear loss in 20,000 Martindale abrasion tests specified in JIS L 1096:2005 after a light fastness test measured under the condition of 110 MJ/㎡ of xenon arc dose in JIS L 0843:2006 light fastness measurement method is 25 mg or less. In the first paragraph,
A sheet-shaped article having a wear loss of 20 mg or less in 20,000 Martindale abrasion tests as specified in JIS L 1096:2010 before a light resistance test. In claim 1 or 2,
A sheet-shaped material containing 10 mass% or more of the above polymer elastomer. In claim 1 or 2,
In the above sheet-shaped article, a sheet-shaped article that additionally satisfies the following condition 3.
Condition 3: When the raised surface of the above sheet-shaped material is placed on a hot plate heated to 150°C and pressed with a pressing load of 2.5 kPa for 10 seconds, the retention rate of the L value is 90% or more and 100% or less. A method for manufacturing a sheet-shaped article comprising the steps of (1) to (4) in this order, wherein the sheet-shaped article satisfies the following conditions 1 and 2.
(1) A polymer elastomer impregnation process in which a fibrous substrate including an ultrafine fiber-forming fiber is impregnated with an aqueous dispersion containing a polymer elastomer, a monovalent cation-containing inorganic salt, and a crosslinking agent, and then heat-treated at a temperature of 140°C or more and 180°C or less, wherein the polymer elastomer has a hydrophilic group and further includes polyetherdiol as a constituent component, and the content of the monovalent cation-containing inorganic salt in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer elastomer.
(2) Ultrafine fiber expression process in which the above ultrafine fiber expression type fiber is treated with alkali and ultrafine fibers are expressed.
(3) Drying process that performs heat treatment at a temperature of 120℃ or higher and 180℃ or lower
(4) A raising process in which at least one side of a sheet-shaped object is raised to form hair on the surface.
Condition 1: The longitudinal strength specified by Method A (45° cantilever method) described in JIS L 1096:2010 “Testing method for raw fabrics of woven and knitted fabrics” is 50 mm or more and 140 mm or less.
Condition 2: The wear loss in 20,000 Martindale abrasion tests specified in JIS L 1096:2005 after a light fastness test measured under the condition of 110 MJ/㎡ of xenon arc dose in JIS L 0843:2006 light fastness measurement method is 25 mg or less. In paragraph 5,
A method for manufacturing a sheet-shaped article, comprising a dyeing process for dyeing a sheet-shaped article or a sheet-shaped article after the above drying process. In paragraph 5 or 6,
A method for producing a sheet-shaped article in which the above monovalent cation-containing inorganic salt is sodium chloride and/or sodium sulfate. In paragraph 5 or 6,
A method for producing a sheet-shaped article in which the cross-linking agent is a carbodiimide-based cross-linking agent.