TWI864197B - Sheet and method for manufacturing the same - Google Patents

Abstract

The purpose of the present invention is to provide a sheet-like article and a manufacturing method thereof that has both soft hand feel and excellent light resistance. In order to achieve the above-mentioned purpose, the sheet-like article of the present invention has the following structure. That is: A sheet-like article, which is a sheet-like article containing a polymer elastic body in a fiber substrate, wherein the fiber substrate contains ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastic body has a hydrophilic group and contains polyether diol as a constituent component, and has N-acyl urea bonds and/or isourea bonds inside the aforementioned polymer elastic body, and the sheet-like article meets the following conditions 1 and 2; Condition 1: The stiffness in the longitudinal direction specified by a specific specification is 40 mm or more and 140 mm or less, Condition 2: After the light resistance test measured under the conditions specified by the specific specification, the stiffness is measured by JIS L The wear loss after 20,000 Martindale abrasion tests specified in 1096:2005 is less than 25 mg.

Description

Sheet and method for manufacturing the same

The present invention relates to a sheet-like article and a manufacturing method thereof, and more particularly to a sheet-like article having excellent softness and light resistance and a manufacturing method thereof.

Sheets made of fiber substrates such as non-woven fabrics and polyurethane have excellent characteristics that natural leather does not have, and are widely used in various applications such as artificial leather. In particular, sheets made of polyester fiber substrates are increasingly used in clothing, chair veneers, and automotive interior materials due to their excellent light resistance.

When manufacturing such a sheet, a combination of steps is generally adopted, in which a fiber substrate is impregnated with an organic solvent solution of polyurethane, the obtained fiber substrate is immersed in water or an organic solvent aqueous solution which is a non-solvent of polyurethane, and the polyurethane is wet-coagulated. At this time, a water-miscible organic solvent such as N,N-dimethylformamide is used as an organic solvent as a solvent of polyurethane, but generally speaking, since organic solvents are highly harmful to the environment, a method that does not use organic solvents is strongly required when manufacturing sheet.

As a specific solution, a method of using a water-dispersible polyurethane in which a polyurethane resin is dispersed in water is being examined instead of the conventional organic solvent-based polyurethane. However, generally speaking, a sheet-like product solidified using the water-dispersible polyurethane tends to be hard to the touch.

One of the main reasons is that the coagulation methods of the two are different. That is, the coagulation method of polyurethane using organic solvent is a so-called wet coagulation method in which the polyurethane molecules dissolved in the organic solvent are replaced with the solvent by water to coagulate. If the polyurethane film is viewed, a porous film with low density is formed. Therefore, it is believed that when polyurethane is impregnated into a fiber substrate and coagulated, the contact area between the fiber and the polyurethane is reduced, and a soft sheet is formed.

On the other hand, water-dispersible polyurethane is mainly coagulated by the so-called wet heat coagulation method, which is mainly by heating to disintegrate the hydration state of the water-dispersible polyurethane dispersion and make the polyurethane emulsion coagulate and coagulate. The obtained polyurethane film structure is a high-density non-porous film. Therefore, it is believed that the connection between the fiber substrate and the polyurethane becomes denser, and the intertwined part of the fiber is strongly grasped, so the feel becomes harder.

To date, in order to obtain a sheet-like product with a soft feel using water-dispersible polyurethane, there has been a proposal to add a thickener to a solution containing water-dispersible polyurethane, treat a fiber substrate impregnated with the solution with hot water, and reduce the polyurethane film covering the fiber substrate to obtain a soft feel (Patent Document 1).

As a coagulation method that also utilizes hot water treatment, there are proposals for a method of obtaining a sheet-like product having excellent moisture and heat resistance by applying a curing treatment after dyeing to prevent the deterioration of physical properties due to the swelling of polyurethane during dyeing (Patent Document 2), or a method of obtaining a sheet-like product having excellent light resistance and softness such as light yellowing resistance and light dyeing fastness by using a water-dispersible polyurethane containing a hindered amine compound (Patent Document 3).

In addition, there is a proposal for obtaining a soft feel by dissolving and mixing an inorganic salt in a forcedly emulsified non-ionic water-dispersible polyurethane to adjust the thermosensitive gelation temperature of the water-dispersible polyurethane gelation temperature, thereby suppressing the phenomenon in which particles of a polymer emulsion dispersed in water are concentratedly attached to the surface layer of a sheet as the water moves, i.e., the so-called migration phenomenon (Patent Document 4).

Furthermore, there is a proposal for a method of making a sheet-like object impregnated with a water-dispersible polyurethane to which polysaccharides are added, and then heating and drying the sheet-like object at two stages to make the polymer elastic body porous and soften the hand feel (Patent Document 5). In this method, in the first stage of drying, the polymer elastic body is completely solidified in a state where the polysaccharides hold water, and in the second stage of drying, the water held by the polysaccharides contained in the polymer elastic body is evaporated in a state where the polymer elastic body is completely solidified, and the portion where the water held by the polysaccharides exists becomes a void, thereby forming a porous structure.

Alternatively, there is a proposal to add a crosslinking agent to a sheet of water-dispersible polyurethane after solidification, heat it and react it, so as to maintain the texture before the addition of the crosslinking agent (Patent Document 6). In this method, regardless of the solidification method of the polyurethane, the water-dispersible polyurethane and the crosslinking agent can be reacted to maintain a state close to the original coagulation structure of the polyurethane. [Prior Art Document] [Patent Document]

Patent document 1: International Publication No. 2015/129602 Patent document 2: Japanese Patent Publication No. 2017-172074 Patent document 3: Japanese Patent Publication No. 2000-265052 Patent document 4: Japanese Patent Publication No. 6-316877 Patent document 5: Japanese Patent Publication No. 2019-112742 Patent document 6: International Publication No. 2016/052189

[Problems to be solved by the invention]

However, when the sheet is used outdoors, such as for automobile interior materials, there is a problem that the ultraviolet rays contained in the sunlight decompose the polyurethane that holds the fibers in the sheet, causing the sheet to deteriorate.

Generally, water-dispersible polyurethane is obtained by reacting a polymer polyol with an organic polyisocyanate and a chain extender, and exhibits various properties depending on the components of the polymer polyol. As representative polymer polyols, there are two types: polyether polyols and polycarbonate polyols. However, although the sheet of polyether polyurethane can be softer than that of polycarbonate polyurethane, it has poor light resistance. In order to take into account both soft feel and light resistance, polyether polyurethane must be used to improve light resistance so that it can withstand actual use.

In the methods disclosed in Patent Documents 1 to 3, although the hardness of the hand feel can be improved by hot water coagulation and a certain degree of soft hand feel can be obtained, the polyurethane does not fully achieve the function as a binder, and the wear resistance becomes insufficient. In the method disclosed in Patent Document 2, since the dye is heated at a high temperature after dyeing, the dye sublimates, so there is a risk of fading in actual use, and the light resistance becomes insufficient. In addition, in the method disclosed in Patent Document 3, although the light resistance is improved by including a hindered amine compound, the film properties are reduced because the compound is contained in the high molecular weight polyol, the gripping force on the fiber is weak, and the wear resistance of the sheet is insufficient. In addition, it cannot be said that the softness is sufficient.

Furthermore, in the method disclosed in Patent Document 4, although a soft touch can be achieved by suppressing migration, since the polyurethane resin is not three-dimensionally cross-linked, the fibers cannot be fully grasped, and the abrasion resistance and light resistance become insufficient.

On the other hand, in the method disclosed in Patent Document 5, a porous structure can be obtained through two-stage drying, but the migration phenomenon cannot be completely suppressed, and the hand feel is insufficient. In addition, since the polyurethane resin is not three-dimensionally cross-linked, it cannot fully grasp the fibers, and the abrasion resistance and light resistance become insufficient.

Alternatively, in the method disclosed in Patent Document 6, although the crosslinking agent is impregnated after the polyurethane solidifies, the reaction between the polyurethane and the crosslinking agent does not proceed much, so the three-dimensional structure caused by the polyurethane and the crosslinking agent cannot be fully formed, and the wear resistance and light resistance become insufficient.

Therefore, the purpose of the present invention is to provide a sheet material and a manufacturing method thereof that has both soft hand feel and excellent light resistance in view of the background of the above-mentioned known technology. [Means for solving the problem]

In order to achieve the above-mentioned purpose, the inventors of the present invention have repeatedly examined and found that by adjusting the drying temperature during the solidification of a polymer elastomer containing polyether diol as a component and using a specific amount of an inorganic salt containing monovalent cations and a crosslinking agent, not only can a sheet be manufactured with consideration for the environment, but also a sheet with better feel and light resistance than conventional sheets can be obtained, thereby achieving the present invention.

That is, the present invention is intended to solve the aforementioned problem. The sheet-like article of the present invention is a sheet-like article containing a polymer elastic body in a fiber substrate, wherein the fiber substrate comprises ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastic body has a hydrophilic group and contains polyether diol as a constituent component, and has N-acyl urea bonds and/or isourea bonds inside the aforementioned polymer elastic body, and the sheet-like article satisfies the following conditions 1 and 2; Condition 1: The stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L 1096:2010 "Test methods for grey fabrics of woven and knitted fabrics" is 40 mm or more and 140 mm or less, Condition 2: The stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L 0843:2006 Light Fastness Test Method, xenon arc dose of 110MJ/ ^m2, after light fastness test, the abrasion loss after 20,000 times of Martindale abrasion test specified in JIS L 1096:2005 is less than 25mg. According to the preferred embodiment of the sheet of the present invention, the abrasion loss after 20,000 times of Martindale abrasion test specified in JIS L 1096:2010 is less than 20mg before the light fastness test.

According to a preferred embodiment of the sheet of the present invention, the sheet contains 10% by mass or more of the aforementioned high molecular weight elastic body.

According to a preferred embodiment of the sheet of the present invention, the sheet further satisfies the following condition 3; Condition 3: When the napped surface of the sheet is placed on a hot plate heated to 150°C and pressed for 10 seconds at a pressure load of 2.5 kPa, the retention rate of the L value is 90% or more and 100% or less. The manufacturing method of the sheet of the present invention is a manufacturing method of the sheet comprising the following steps (1) to (4) in sequence. (1) A polymer elastomer impregnation step, which comprises impregnating a fibrous substrate including ultrafine fiber-developing fibers with an aqueous dispersion containing a polymer elastomer, an inorganic salt containing monovalent cations, and a crosslinking agent, and then performing a heat treatment at a temperature of 120° C. to 180° C., wherein the polymer elastomer has a hydrophilic group and contains polyether glycol as a constituent component, and the inorganic salt containing monovalent cations in the aqueous dispersion is The content of salt is 10 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the aforementioned high molecular weight elastic body; (2) an ultrafine fiber development step, which is to treat the aforementioned ultrafine fiber development type fiber with alkali to develop the ultrafine fibers; (3) a drying step, which is to apply heat treatment at a temperature of 120°C to 180°C; (4) a raising step, which is to raise at least one side of the unraised sheet to form fluff on the surface. According to a preferred embodiment of the method for manufacturing a sheet of the present invention, after the aforementioned drying step, it includes a step of dyeing the unraised sheet or the sheet.

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

According to a preferred embodiment of the method for producing a sheet-like article of the present invention, the crosslinking agent is a carbodiimide crosslinking agent. [Effect of the invention]

According to the present invention, a sheet having both soft feel and excellent light resistance can be obtained.

[Form used to implement the invention]

The sheet-like article of the present invention is a sheet-like article containing a polymer elastic body in a fiber substrate, wherein the fiber substrate comprises ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastic body has a hydrophilic group and contains polyether diol as a constituent component, and has N-acyl urea bonds and/or isourea bonds inside the polymer elastic body, and the sheet-like article satisfies the following conditions 1 and 2; Condition 1: The stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L 1096:2010 "Test methods for grey fabrics of woven and knitted fabrics" is 40 mm or more and 140 mm or less, Condition 2: The stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L After the light fastness test measured under the conditions of 110MJ/ ^m2 of xenon arc in 0843:2006, the abrasion loss after 20,000 times of Martindale abrasion test specified in JIS L 1096:2005 is less than 25mg.

The constituent elements are described in detail below, but the present invention is not limited to the scope of the following description as long as it does not exceed the scope of the present invention.

[Ultrafine fibers] As resins that can be used for ultrafine fibers used in the present invention, polyester resins or polyamide resins can be cited from the viewpoint of excellent durability, especially mechanical strength, heat resistance and light resistance. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, etc. Polyester resins can be obtained, for example, from dicarboxylic acids and/or their ester-forming derivatives and diols.

As the dicarboxylic acid and/or its ester-forming derivatives used in the aforementioned polyester resin, there can be cited terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and its ester-forming derivatives. Moreover, the ester-forming derivatives mentioned in the present invention are lower alkyl esters, anhydrides, acyl chlorides, etc. of dicarboxylic acids. Specifically, methyl esters, ethyl esters, and hydroxyethyl esters are preferably used. As the dicarboxylic acid and/or its ester-forming derivatives used in the present invention, a more preferred embodiment is terephthalic acid and/or its dimethyl ester.

Examples of the diol used for the polyester resin include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, cyclohexanedimethanol, and the like, among which ethylene glycol is preferably used.

When a polyamide resin is used as the resin for ultrafine fibers, polyamide 6, polyamide 66, polyamide 56, polyamide 610, polyamide 11, polyamide 12, copolymerized polyamide, and the like can be used.

The resin used for ultrafine fibers may contain inorganic particles such as titanium oxide particles, lubricants, pigments, thermal stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents, etc., depending on the purpose.

Furthermore, the resin used in the ultrafine fibers preferably contains ingredients derived from biomass resources.

When using polyester resin as a resin for ultrafine fibers, the bioresource-derived component may be a dicarboxylic acid or an ester-forming derivative thereof as a constituent component, or a bioresource-derived component may be used as a diol. However, from the viewpoint of reducing environmental load, it is preferred to use a bioresource-derived component for both the dicarboxylic acid or an ester-forming derivative thereof and the diol.

When using polyamide resin as a component derived from biomass resources as a resin for ultrafine fibers, polyamide 56, polyamide 610, and polyamide 11 are preferably used from the viewpoint of economically obtaining a raw material derived from biomass resources or physical properties of the fiber.

As the cross-sectional shape of the ultrafine fiber, either a circular cross-sectional shape or an irregular cross-sectional shape may be adopted. Specific examples of the irregular cross-sectional shape include an ellipse, a flat shape, a polygon such as a triangle, a fan shape, a cross shape, and the like.

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. Since 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 can be made softer. In addition, the quality of the fluff can be improved. On the other hand, since 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 can have excellent color rendering properties after dyeing. In addition, when the fluff is treated by polishing, the ease of dispersion and separation of the extremely fine fibers in bundles can be improved.

The average single fiber diameter mentioned in the present invention is measured by the following method. That is: (1) The cross section of a sheet-like object cut in the thickness direction is observed by scanning electron microscope (SEM). (2) The fiber diameters of 50 arbitrary ultra-fine fibers within the observation surface are measured in three directions in each ultra-fine fiber cross section. However, when ultra-fine fibers with irregular cross sections are used, the cross-sectional area of the single fiber is first measured, and the diameter of the circle forming the cross-sectional area is calculated using the following formula. The diameter thus obtained is regarded as the single fiber diameter of the single fiber.・Single fiber diameter (μm) = (4 × (single fiber cross-sectional area (μm ² )) / π) ^1/2 (3) Calculate the arithmetic mean (μm) of the total 150 points obtained and round off to the second decimal place.

[Fiber substrate] The fiber substrate used in the present invention includes the aforementioned ultra-fine fibers. In addition, ultra-fine fibers of different raw materials may be mixed in the fiber substrate.

As a specific form of the aforementioned fibrous substrate, a nonwoven fabric formed by entanglement of the aforementioned ultrafine fibers or a nonwoven fabric formed by entanglement of fiber bundles of ultrafine fibers can be used. Among them, from the viewpoint of the strength and hand feel of the sheet, it is more preferable to use a nonwoven fabric formed by entanglement of fiber bundles of ultrafine fibers. From the viewpoint of softness and hand feel, it is particularly preferable to use a nonwoven fabric in which the ultrafine fibers constituting the fiber bundles of ultrafine fibers are appropriately spaced from each other and have gaps. Thus, a nonwoven fabric formed by entanglement of ultrafine fiber bundles can be obtained, for example, by entanglement of ultrafine fiber development type fibers in advance and then developing the ultrafine fibers. Also, a nonwoven fabric in which the ultrafine fibers constituting the fiber bundles of ultrafine fibers are appropriately spaced from each other and have gaps can be obtained, for example, by using sea-island type composite fibers, which can be obtained by removing the sea component to form gaps between the island components.

The nonwoven fabric may be either a short-fiber nonwoven fabric or a long-fiber nonwoven fabric, but from the viewpoint of the feel and quality of the sheet, short-fiber nonwoven fabric is more preferably used.

When using a staple nonwoven fabric, the staple fiber length is preferably in the range of 25 mm to 90 mm. Since the fiber length is set to 25 mm or more, more preferably 35 mm or more, and particularly preferably 40 mm or more, it is easy to obtain a sheet-like product with excellent wear resistance by entanglement. In addition, since the fiber length is set to 90 mm or less, more preferably 80 mm or less, and particularly preferably 70 mm or less, a sheet-like product with better feel and quality can be obtained.

In the present invention, when a nonwoven fabric is used as a fiber substrate, a woven fabric or a knitted fabric may be inserted into the nonwoven fabric, or may be laminated or attached to the back for the purpose of improving strength. The average single fiber diameter of the fibers constituting the woven fabric or the knitted fabric is preferably 0.3 μm or more and 10 μm or less, because it can suppress damage during needle piercing and maintain strength.

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

[Polymer elastic body] In the sheet-like material of the present invention, examples of the polymer elastic body include water-dispersible silicone resin, water-dispersible acrylic resin, water-dispersible urethane resin, or copolymers thereof. Among them, water-dispersible polyurethane resin is preferably used in terms of hand feel.

As a water-dispersible polyurethane resin, it is preferable to use a resin obtained by reacting a high molecular weight polyol having a number average molecular weight of preferably 500 to 5,000, an organic polyisocyanate and a chain extender. In addition, in order to improve the stability of the water-dispersible polyurethane dispersion, it is preferable to use an active hydrogen component containing a hydrophilic group. By setting the number average molecular weight of the high molecular weight polyol to 500 or more, preferably to 1,500 or more, it is easy to prevent the hand feel from becoming hard. In addition, by setting the number average molecular weight to 5,000 or less, preferably to 4,000 or less, it is easy to maintain the strength of the polyurethane as a binder. The following describes the use of a water-dispersible polyurethane resin as a high molecular weight elastomer.

(1) Reaction components of water-dispersible polyurethane resin First, the reaction components of water-dispersible polyurethane resin are explained.

(1-1) Polymer polyols In the sheet-like material of the present invention, the aforementioned polymer elastomer contains polyether diol as a constituent component. The content of polyether diol in the polymer polyol is preferably 50% by mass or more of the total polymer polyol, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Specific examples of polyether diols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymerized polyether diols of these. Moreover, in this specification, the so-called "containing as a constituent component" means containing as a monomer component or oligomer component constituting the polymer elastomer. Polyether diols have a high degree of freedom of ether bonds, a low glass transition temperature, and weak cohesion, so it is easy to obtain polyurethane with excellent softness.

(1-2) Organic diisocyanates The organic diisocyanates used in the present invention include aromatic diisocyanates having a carbon number of 6 to 20 (excluding carbon in the NCO group, the same below), aliphatic diisocyanates having a carbon number of 2 to 18, alicyclic diisocyanates having a carbon number of 4 to 15, aromatic aliphatic diisocyanates 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 of these.

Specific examples of the aromatic diisocyanate having a carbon number of 6 to 20 include 1,3- and/or 1,4-phenylene diisocyanate, 2,4- and/or 2,6-methylphenylene diisocyanate, 2,4'- and/or 4,4'-diphenylmethane diisocyanate (hereinafter referred to as MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, and 1,5-naphthylene diisocyanate.

Specific examples of the aliphatic diisocyanate having a carbon number of 2 or more and 18 or less include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylhexanoate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

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

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

Among these, the preferred organic diisocyanate is alicyclic diisocyanate. Moreover, the particularly preferred diisocyanate is dicyclohexylmethane-4,4'-diisocyanate.

(1-3) Chain extenders As the chain extenders used in the present invention, water, low molecular weight diols such as "ethylene glycol, propylene glycol, 1,3-butanediol, 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 "xylene diamine", alkanolamines such as "ethanolamine", hydrazine, dihydrazide such as "adipic acid dihydrazide", and mixtures of two or more thereof can be cited.

Among these, preferred chain extenders are water, low molecular weight diols, and aromatic diamines, and particularly preferred are 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 an inorganic salt containing a monovalent cation to the solution containing the water-dispersible polyurethane. In addition, as necessary, it may also contain a coloring agent such as titanium oxide, an ultraviolet absorber (diphenyl ketone series, benzotriazole series, etc.) or an antioxidant [hindered phenols such as 4,4-butylene-bis(3-methyl-6-1-butylphenol); organic phosphites such as triphenyl phosphite and trichloroethyl phosphite], various stabilizers, inorganic fillers (calcium carbonate, etc.), etc.

(3) Composition of water-dispersible polyurethane resin In the water-dispersible polyurethane used in the present invention, as a component for making the polyurethane contain a hydrophilic group, for example, an active hydrogen component containing a hydrophilic group can be cited. As the active hydrogen component containing a hydrophilic group, a compound containing a non-ionic group and/or an anionic group and/or a cationic group and active hydrogen can be cited.

Examples of the compound having a non-ionic group and an active hydrogen group include a compound 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 a triol such as trihydroxymethylpropane or trihydroxymethylbutane.

Examples of the compound having an anionic group and an active hydrogen include carboxyl-containing compounds such as 2,2-dihydroxymethylpropionic acid, 2,2-dihydroxymethylbutyric acid, and 2,2-dihydroxymethylpentanoic acid, and their derivatives, or sulfonic acid-containing compounds 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 the compound containing a cationic group and an active hydrogen include compounds containing a tertiary amine group such as 3-dimethylaminopropanol, N-methyldiethanolamine, and N-propyldiethanolamine, and their derivatives.

The aforementioned active hydrogen component containing a hydrophilic group may also be used in the form of a salt neutralized by a neutralizer.

The active hydrogen component containing a hydrophilic group used in the polyurethane molecule is preferably 2,2-dihydroxymethylpropionic acid, 2,2-dihydroxymethylbutyric acid and their neutralized salts from the viewpoint of the mechanical strength and dispersion stability of the water-dispersible polyurethane resin.

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

In the present invention, the polymer elastomer has N-acylurea bonds and/or isourea bonds inside. Here, the polymer elastomer has N-acylurea bonds and/or isourea bonds inside, which means that the polymer elastomer has N-acylurea bonds and/or isourea bonds. When a water-dispersible polyurethane resin is used as the polymer elastomer, the N-acylurea bonds and/or isourea bonds can be formed by reacting the hydroxyl group and/or carboxyl group present as the active hydrogen component containing a hydrophilic group with a carbodiimide-based crosslinking agent. In this way, a three-dimensional cross-linked structure formed by N-acylurea bonds and/or isourea bonds with excellent properties such as light resistance, heat resistance, and wear resistance and flexibility is imparted to the molecules of the polymer elastomer, which can maintain the flexibility of the sheet while significantly improving the physical properties such as wear resistance.

Furthermore, the presence of the above-mentioned N-acylurea group or isourea group in the polymer elastomer can be analyzed by, for example, time-of-flight secondary ion mass spectrometry (TOF-SIMS analysis) or other mapping processing (analyzer, for example, "TOF. SIMS 5" manufactured by ION-TOF Corporation) or infrared spectroscopic analysis (analyzer, for example, "FT/IR 4000 Series" manufactured by JASCO Corporation) on the cross section of the sheet.

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

The number average molecular weight of the aforementioned high molecular weight elastic body can be determined by gel permeation chromatography, for example, under the following conditions. ・Apparatus: HLC-8220 manufactured by Tosoh Corporation ・Column: Tosoh TSKgel α-M ・Solvent: N,N-dimethylformamide (DMF) ・Temperature: 40°C ・Calibration: Polystyrene The high molecular weight elastic body used in the present invention is preferably present inside the fiber substrate from the viewpoint of appropriately grasping the fibers in the sheet and preferably having fluff on at least one side of the sheet.

[Sheet] The sheet of the present invention is important in that the stiffness in the longitudinal direction as specified in the A method (45° cantilever method) in JIS L 1096:2010 "Test methods for grey fabrics of woven and knitted fabrics" is 40 mm or more and 140 mm or less. By setting the stiffness within the above range, it can have appropriate softness and resilience. Regarding the stiffness, from the point of view of obtaining a sheet with resilience, it is preferably 50 mm or more, and more preferably 55 mm or more. From the point of view of obtaining a sheet with flexibility, it is preferably 120 mm or less, and more preferably 110 mm or less.

The so-called longitudinal direction in the sheet-like object of the present invention refers to the direction in which the sheet-like object is subjected to a raising treatment. As a method for exploring the direction in which the raising treatment is performed, it can be appropriately adopted according to the composition of the sheet-like object such as visual confirmation when scratched with a finger or SEM photography. That is, the direction in which the fluff fibers can lie down or stand up when scratched with a finger becomes the longitudinal direction. Moreover, by SEM photography, on the surface of the sheet-like object scratched with a finger, the direction in which the most fluff fibers lie down becomes the longitudinal direction. On the other hand, the so-called transverse direction in the sheet-like object of the present invention is the direction perpendicular to the longitudinal direction.

Furthermore, the sheet of the present invention is important in that the abrasion loss after the light fastness test measured under the conditions of 110 MJ/ ^m2 of the xenon arc dose in JIS L 0843:2006 light fastness test method and the Martindale abrasion test specified in JIS L 1096:2005 after 20,000 times is 25 mg or less. Since the abrasion loss after the light fastness test is set to the above range, even if the sheet is used for a long time in a harsh environment such as exposure to sunlight, the degradation of the polymer elastomer can be suppressed, and the appearance of the sheet can be maintained. From the viewpoint of suppressing the degradation of the appearance of the sheet, the abrasion loss is preferably 23 mg or less, and more preferably 20 mg or less.

The sheet of the present invention preferably has a wear loss of 20 mg or less in the Martindale abrasion test 20,000 times specified in JIS L 1096:2010 before the light resistance test. Since the wear loss before the light resistance test is set to the above range, it is easy to suppress hair loss or appearance degradation during actual use. From the perspective of being able to further suppress hair loss during actual use, the wear loss is preferably 18 mg or less, and more preferably 15 mg or less.

The sheet of the present invention preferably contains 10% by mass or more of a high molecular weight elastomer. From the perspective of suppressing breakage caused by tension in the process or hair loss during actual use, it is more preferably 12% by mass or more, and particularly preferably 15% by mass or more. There is no particular upper limit to the content, but it is usually 50% by mass or less, preferably 40% by mass or less, and more preferably 35% by mass or less.

The sheet of the present invention preferably further satisfies the following condition 3. Condition 3: When the napped surface of the sheet is placed on a hot plate heated to 150°C and pressed for 10 seconds with a pressing load of 2.5 kPa, the retention rate of the L value (hereinafter sometimes simply referred to as the L value retention rate) is 90% or more and 100% or less.

Among them, since the L value retention rate is 90% or more, more preferably 92% or more, and even more preferably 95% or more, the sheet has high heat resistance.

Furthermore, the "raised surface of the sheet" in the present invention refers to the surface of the sheet after the raising treatment. In addition, the so-called L value is the L value defined by the Commission International on Illumination (CIE), but the so-called L value retention rate in the present invention refers to the ratio of brightness change under heating and pressing conditions, that is, it refers to the degree to which a sheet with a dark color before heating and pressing does not become brighter after heating and pressing.

In the present invention, the L value retention rate refers to a value measured and calculated by the following procedure. (1) Cut a piece of material 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 on a hot plate heated to 150°C (e.g., "CHP-250DN" manufactured by AS ONE Co., Ltd.) with the napped surface facing downward. (3) Place a pressure head adjusted to a pressure load of 2.5 kPa on the test piece and hold for 10 seconds. (4) Remove the pressure head from the test piece and measure the L value of the napped surface of the test piece using the aforementioned colorimeter. (5) Calculate the L value retention rate by the following formula.

L value retention rate (%) = (L value measured by (1)) / (L value measured by (4)) × 100 In order to make the stiffness or the wear loss before and after the light resistance test, and the L value retention rate within the above range, for example, a sheet can be produced through the polymer elastomer impregnation step, ultrafine fiber development step, and drying step described later. After the polymer elastomer is impregnated, the ultrafine fiber development step can be performed to create a gap between the ultrafine fiber and the polymer elastomer, and a soft feel can be easily obtained. In addition, for example, by heat treatment (aging treatment) at a temperature of 120°C to 180°C in the drying step, the particles of the polymer elastomer can be aggregated, and the light resistance, abrasion resistance, and heat resistance can be easily improved. Furthermore, since the thermosensitive coagulation temperature of the aqueous dispersion is set to the range described below, the polyurethane accompanying the evaporation of water can be suppressed from being preferentially present (migrated) on the surface of the sheet, and the L value retention rate can be improved.

[Method for manufacturing sheet-like article] Next, the method for manufacturing the sheet-like article of the present invention is described.

The method for producing a sheet-like article of the present invention comprises the following steps (1) to (4) in sequence. (1) A polymer elastic body impregnation step, which is to impregnate a fibrous substrate comprising ultrafine fiber-developing fibers with a water dispersion containing a polymer elastic body, an inorganic salt containing monovalent cations, and a crosslinking agent, and then heat-treat the polymer elastic body at a temperature of 120°C to 180°C. The polymer elastic body has a hydrophilic group and contains polyether glycol as a constituent component. The inorganic salt containing monovalent cations in the water dispersion is The content of the salt is 10 parts by mass to 50 parts by mass relative to 100 parts by mass of the aforementioned high molecular weight elastic body; (2) an ultrafine fiber development step, which is to treat the aforementioned ultrafine fiber development type fiber with alkali to develop the ultrafine fibers; (3) a drying step, which is to apply heat treatment at a temperature of 120°C to 180°C; (4) a raising step, which is to raise at least one side of the unraised sheet to form fluff on the surface.

In the present invention, the so-called "unraised sheet" refers to a sheet before raising treatment obtained by a method comprising at least the above steps (1) to (3) in sequence.

In the present invention, as a means of obtaining ultra-fine fibers, it is preferable to use ultra-fine fiber-developed type fibers. After the ultra-fine fiber-developed type fibers are entangled in advance to form a non-woven fabric, the fibers are ultra-finely refined to obtain a non-woven fabric in which the ultra-fine fiber bundles are entangled.

As ultra-fine fiber-developing fibers, thermoplastic resins of two components (two or three components when island fibers are core-sheath composite fibers) having different solvent solubility are used as sea components and island components, and the aforementioned sea component is dissolved and removed by using a solvent or the like, and sea-island type composite fibers in which the island components are ultra-fine fibers are used. Since appropriate spaces can be provided between the island components, that is, between the ultra-fine fibers inside the fiber bundle, when the sea component is removed, this is better from the viewpoint of the feel and surface quality of the sheet.

As sea-island type composite fibers, it is preferable to use a sea-island type composite nozzle to alternately arrange two components of sea component and island component (three components when the island fiber is a core-sheath composite fiber) and use a polymer alternate arrangement body to spin it. This is from the perspective of obtaining ultra-fine fibers with uniform single fiber diameter.

As the sea component of the island-type composite fiber, polyethylene, polypropylene, polystyrene, copolymerized polyesters copolymerized with sodium sulfoisophthalic acid or polyethylene glycol, and polylactic acid can be used. However, from the viewpoint of yarn-making properties and easy dissolution, polystyrene and copolymerized polyesters are preferably used.

It is better to dissolve and remove the sea component after the high molecular weight elastic body is applied, as described below.

The mass ratio of the sea component to the island component in the sea-island type composite fiber used in the present invention is preferably in the range of sea component: island component = 10:90 to 80:20. If the mass ratio of the sea component is 10% by mass or more, the island component is easily and sufficiently refined. In addition, if the mass ratio of the sea component is 80% by mass or less, the productivity is improved due to the small proportion of the eluted component. The mass ratio of the sea component to the island component is more preferably in the range of sea component: island component = 20:80 to 70:30.

Furthermore, the fiber knot is preferably in the form of a nonwoven fabric, and either a short fiber nonwoven fabric or a long fiber nonwoven fabric as described above can be used. However, if it is a short fiber nonwoven fabric, the fibers in the thickness direction of the fiber substrate are more than those in a long fiber nonwoven fabric, and the surface of the fiber substrate can be obtained with a high density when raised, which is preferred.

When using short-staple nonwoven fabric as the fiber entanglement body, it is preferred to perform a rolling process on the obtained ultrafine fiber-developed fiber and cut it into a specified length to obtain raw cotton. The rolling process and the cutting process can be performed by well-known methods.

Next, the obtained raw cotton is made into a fiber web by a cross-lapping machine, etc., and a short-fiber nonwoven fabric is obtained by entanglement of the fiber web. Needle piercing treatment, water jet puncture treatment, etc. can be used as a method for entanglement of the fiber web to obtain a short-fiber nonwoven fabric.

Furthermore, the short-fiber nonwoven fabric and the woven fabric obtained by lamination can be intertwined and integrated. In the intertwining and integration of the short-fiber nonwoven fabric and the woven fabric, the woven fabric can be laminated on one side or both sides of the short-fiber nonwoven fabric, or the woven fabric can be sandwiched between a plurality of short-fiber nonwoven fabric nets, and then the fibers of the short-fiber nonwoven fabric and the woven fabric can be intertwined with each other by needle piercing treatment, water jet puncture treatment, etc.

The apparent density of the short-fiber nonwoven fabric containing the composite fiber (ultrafine fiber-developed fiber) after needle punching or water jet puncture treatment is preferably 0.15 g/cm ³ or more and 0.45 g/cm ³ or less. By setting the apparent density preferably to 0.15 g/cm ³ or more, the fiber substrate can obtain sufficient morphological stability and dimensional stability. On the other hand, by setting the apparent density preferably to 0.45 g/cm ³ or less, sufficient space for providing the polymer elastomer can be maintained.

From the viewpoint of densification, the nonwoven fabric thus obtained is preferably shrunk by dry heat or wet heat or both to further increase the density. In addition, the nonwoven fabric can also be compressed in the thickness direction by calendering treatment or the like.

The method for producing a sheet-like article of the present invention comprises (1) a polymer elastic body impregnation step, which comprises impregnating a fibrous substrate comprising ultrafine fiber-developing type fibers with an aqueous dispersion containing a polymer elastic body, an inorganic salt containing monovalent cations, and a crosslinking agent, and then performing a heat treatment at a temperature of 120° C. to 180° C. The polymer elastic body has a hydrophilic group and contains polyether diol as a constituent component, and the content of the inorganic salt containing monovalent cations in the aqueous dispersion is 10 parts by mass to 50 parts by mass relative to 100 parts by mass of the polymer elastic body.

In the method for producing a sheet-like article of the present invention, a polymer elastic body having a hydrophilic group and containing polyether diol as a constituent is imparted to a fibrous substrate. When a nonwoven fabric is used as the fibrous substrate, the impartation of the polymer elastic body can be performed on either a nonwoven fabric containing composite fibers or a nonwoven fabric that has been extremely finely fiberized.

In the method for producing a sheet-like article of the present invention, the aforementioned polymer elastic body contains polyether diol as a constituent component. The reason is as described in the above item (1-1) polymer polyol.

In the manufacturing method of the sheet of the present invention, the solidification after the high molecular weight elastic body is applied is a dry heat solidification method using a heating treatment at a temperature of 120°C to 180°C. In other solidification methods, such as the hot water solidification method in which the high molecular weight elastic body is solidified in hot water, the high molecular weight elastic body diffuses into the hot water and a part of it falls off, so there is a concern about the processability. In addition, in the acid solidification method in which the high molecular weight elastic body is solidified by acid, the acid solution remaining in the sheet must be neutralized, which is not good in terms of processability. On the other hand, the dry heat coagulation method used in the present invention is a very simple method of heat-treating a sheet impregnated with a polymer elastomer using a hot air dryer or the like, and is a method with excellent processability without the worry of the polymer elastomer falling off.

In the manufacturing method of the sheet-like article of the present invention, the heating temperature in the dry heat coagulation is 120°C to 180°C. The heating temperature is preferably 140°C or higher. This is because the polymer elastomer can be quickly coagulated, and the polymer elastomer is prevented from being biased to the bottom of the sheet due to its own weight. Furthermore, the present invention must be used in conjunction with a crosslinking agent, but by setting the temperature to the above, the crosslinking reaction can be fully promoted to form a three-dimensional mesh structure, improve physical properties or light resistance and heat resistance. The heating temperature is preferably 175°C or lower. This is because the thermal degradation of the polymer elastomer can be suppressed.

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

The aqueous dispersion used in the present invention may contain 40% by mass or less of a water-soluble organic solvent in 100% by mass of the aqueous dispersion in order to improve storage stability or film-forming properties. However, from the perspective of preserving the film-forming environment, the content of the organic solvent is preferably 1% by mass or less.

In the method for producing a sheet of the present invention, an inorganic salt containing monovalent cations is contained in the aqueous dispersion. By containing the inorganic salt containing monovalent cations, thermosensitive coagulation property can be imparted to the aqueous dispersion. The so-called thermosensitive coagulation property in the present invention refers to the property that when the aqueous dispersion is heated, if a certain temperature (thermosensitive coagulation temperature) is reached, the fluidity of the aqueous dispersion decreases and coagulation proceeds.

In the method for producing the sheet of the present invention, after the aqueous dispersion is applied to the fiber substrate, it is heated at a temperature of 120°C to 180°C to dry-heat solidify the fiber substrate, thereby applying the polymer elastomer to the fiber substrate.

When the polymer elastic body does not have heat-sensitive coagulation, the polymer elastic body migrates to the sheet surface as the water evaporates. Furthermore, as the water evaporates, the polymer elastic body solidifies in a state where it is biased around the fibers, so the polymer elastic body covers the fibers and forms a structure that strongly restricts their movement. As a result, the feel of the sheet is significantly hardened.

The heat-sensitive coagulation temperature of the aqueous dispersion is preferably 55°C to 80°C. In order to improve the stability of the aqueous dispersion during storage and to suppress the adhesion of the polymer elastomer to the machine during operation, it is more preferable to set the heat-sensitive coagulation temperature to 60°C or above. The migration of the polymer elastomer to the surface of the fiber substrate can be suppressed. Furthermore, by coagulating the polymer elastomer before the water evaporates from the fiber substrate, a structure similar to that obtained by wet coagulation of a solvent-based polymer elastomer can be formed, that is, a structure in which the polymer elastomer does not strongly restrain the fiber can be formed. Since good softness and resilience can be achieved, it is more preferable to set the heat-sensitive coagulation temperature to 70°C or below.

In the present invention, it is important to use an inorganic salt containing monovalent cations among the inorganic salts used as the thermosensitive coagulant. The aforementioned inorganic salt containing monovalent cations is preferably sodium chloride and/or sodium sulfate. In the known method, an inorganic salt having divalent cations such as magnesium sulfate or calcium chloride can be appropriately used as a thermosensitive coagulant, but these inorganic salts greatly affect the stability of the aqueous dispersion even when added in small amounts, so it is difficult to strictly control the thermosensitive gelation temperature according to the type of polymer elastomer, and there are also issues such as concerns about gelation during the adjustment or storage of the aqueous dispersion. On the other hand, inorganic salts containing monovalent cations with small ionic valence have little effect on the stability of the aqueous dispersion. The stability of the aqueous dispersion can be ensured by adjusting the addition amount, and the thermal coagulation temperature can be strictly controlled.

Furthermore, in the present invention, the content of the inorganic salt containing monovalent cations in the aqueous dispersion is, importantly, 10 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the polymer elastomer. Since the content is set to 10 parts by mass or more, the ions present in large quantities in the aqueous dispersion act uniformly on the polymer elastomer particles, and the solidification can be completed quickly at a specific heat-sensitive solidification temperature. Thereby, in the state in which a large amount of water is contained in the fiber substrate as described above, a more significant effect can be obtained in the solidification of the polymer elastomer. As a result, a structure very similar to that obtained by wet solidification of a solvent-based polymer elastomer can be formed, achieving good softness and resilience. Furthermore, since the addition amount is set to the above, the inorganic salt becomes an inhibitor of the fusion of the polymer elastomer particles, and the hardening of the polymer elastomer due to the continuous film formation can be suppressed. On the other hand, since the content is set to 50 parts by mass or less, the continuous film structure of the polymer elastomer can be left appropriately, and the reduction of physical properties can be suppressed. In addition, the stability of the aqueous dispersion can be maintained.

In the method for producing the sheet of the present invention, it is important to contain a crosslinking agent in the aqueous dispersion. By using the crosslinking agent to introduce a three-dimensional mesh structure into the polymer elastic body, physical properties such as wear resistance can be improved. Furthermore, by using it in combination with the aforementioned inorganic salt containing monovalent cations, the solidification of the polymer elastic body and the reaction of the polymer elastic body with the crosslinking agent can be carried out simultaneously, and the sheet can be softened by forming a dense three-dimensional mesh structure and controlling the fiber bonding structure, and at the same time, the sheet can also achieve high physical properties or high light resistance and high heat resistance. That is, in order to improve the physical properties, light resistance, and heat resistance of the sheet, it is necessary and indispensable to use an inorganic salt containing monovalent cations and a crosslinking agent and to control the heating temperature of dry heat coagulation.

Since the polymer elastic body obtained after the reaction has excellent light resistance, heat resistance, and abrasion resistance, and also good softness, the crosslinking agent is preferably a carbodiimide crosslinking agent.

The manufacturing method of the sheet of the present invention includes (2) an ultrafine fiber development step, which is to alkali-treat the ultrafine fiber development type fiber to develop the ultrafine fibers. By performing the alkali treatment after the polymer elastic body is applied, gaps are generated between the polymer elastic body and the ultrafine fibers due to the components dissolved by the alkali treatment, so that the polymer elastic body does not directly grasp the ultrafine fibers, and the feel of the sheet becomes softer.

When using the sea-island type composite fiber as the ultrafine fiber-developing fiber, the fiber ultra-fine processing (sea removal processing) can be performed, for example, by immersing the sea-island type composite fiber in a solvent and squeezing out the liquid. As the solvent for dissolving the sea component, an alkaline aqueous solution such as sodium hydroxide or hot water can be used.

In the ultra-fine fiber development step, continuous dyeing machines, vibration-cleaning deseasing machines, liquid jet dyeing machines, rope dyeing machines, and interlaced dyeing machines can be used.

After the ultra-fine fiber development step, it is preferred to perform a sufficient cleaning step after the alkali treatment. By performing the cleaning step, the alkali or inorganic salt containing monovalent cations attached to the sheet material will not remain in the sheet, and the sheet material can be processed without affecting the production equipment. If the environment or safety is considered, water is preferably used as the cleaning liquid.

The method for producing a sheet of the present invention includes (3) a drying step of applying heat treatment at a temperature of 120° C. to 180° C. In the ultrafine fiber development step, since the bonds of the polymer elastomer are partially decomposed by the solvent that dissolves the components other than the ultrafine fibers in the ultrafine fiber development type fiber, the particles of the polymer elastomer can be aggregated by aging treatment caused by drying, thereby further improving the physical properties such as light resistance, abrasion resistance, and heat resistance.

In the manufacturing method of the sheet of the present invention, the heating temperature of the aging treatment by drying is 120°C or higher and 180°C or lower. In order to improve the effect of the aging treatment and improve the physical properties such as light resistance, abrasion resistance, and heat resistance, it is preferably 140°C or higher, and more preferably 150°C or higher. In order to inhibit the thermal degradation of the polymer elastomer, it is preferably 175°C or lower, and more preferably 170°C or lower.

The manufacturing method of the sheet of the present invention preferably includes a dyeing step of dyeing the un-fluffed sheet or sheet after the aforementioned drying step. As this dyeing treatment, various methods commonly used in the field can be adopted, for example: liquid flow dyeing treatment using a reel dyeing machine or a liquid flow dyeing machine, hot melt dyeing treatment using a continuous dyeing machine, or dyeing treatment on the fleece surface by roller printing, screen printing, inkjet printing, sublimation printing, vacuum sublimation printing, etc. Among them, it is preferred to use a liquid flow dyeing machine from the viewpoint that the un-fluffed sheet or sheet can be softened by giving a rubbing effect while dyeing the un-fluffed sheet or sheet. In addition, various resin finishing processes can be applied after dyeing as needed.

The dyeing temperature also depends on the type of fiber, but is preferably set to 80°C or higher and 150°C or lower. By setting the dyeing temperature to 80°C or higher, more preferably 110°C or higher, the fiber can be efficiently dyed. On the other hand, by setting the dyeing temperature to 150°C or lower, more preferably 130°C or lower, the degradation of the polymer elastomer can be prevented.

The dye used in the present invention can be selected according to the type of fiber constituting the fiber substrate, and there is no particular limitation. For example, if it is a polyester fiber, a disperse dye can be used, and if it is a polyamide fiber, an acid dye or a gold-containing dye can be used. Furthermore, a combination of these can be used. When dyeing with a disperse dye, reduction washing can be performed after dyeing.

It is also preferable to use a dyeing auxiliary during dyeing. By using a dyeing auxiliary, the uniformity and reproducibility of dyeing can be improved. In addition, a finishing agent such as a softener such as polysilicone, an antistatic agent, a water repellent, a flame retardant, a light fastness agent, and an antibacterial agent can be applied in the same bath as dyeing or after dyeing.

In the present invention, regardless of the order of the dyeing step, from the perspective of manufacturing efficiency, cutting the film in half in the thickness direction is also a preferred aspect.

The method for producing a sheet-like article of the present invention includes (4) a raising step, which is to raise at least one side of an unraised sheet-like article to form fluff on the surface, regardless of whether the dyeing step is performed before or after the dyeing step. The method for forming the fluff is not particularly limited, and various methods commonly used in the field such as polishing with sandpaper etc. can be used. If the length of the fluff is too short, it is difficult to obtain a beautiful appearance, and if it is too long, pilling tends to occur easily, so the length of the fluff is preferably set to be not less than 0.2 mm and not more than 1.0 mm.

In one aspect of the present invention, silicone or the like may be applied as a lubricant to the un-raised sheet before the raising treatment. By applying the lubricant, the raising of the surface during grinding is facilitated, and the surface quality becomes very good, which is preferred. In addition, an antistatic agent may be applied before the raising treatment. By applying the antistatic agent, the grinding powder generated from the sheet during grinding is not easily accumulated on the sandpaper, which is preferred.

Furthermore, in one aspect of the present invention, the surface can be given a design feature as needed. For example, post-processing such as perforation, embossing, laser processing, ultrasonic welding (pinsonic) processing, and printing processing can be applied. [Example]

Next, the sheet-like object of the present invention is 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-like objects: Using a scanning electron microscope (SEM, VE-7800 manufactured by KEYENCE Co., Ltd.), the cross-section of the sheet-like object perpendicular to the thickness direction containing the fibers was observed at 3000 times. The diameters of 50 single fibers randomly selected within a field of view of 30μm×30μm were measured in μm units to the first decimal place.

This is done at three locations, and the diameters of a total of 150 single fibers are measured, and the average value is calculated to the first decimal place. When fibers with a fiber diameter exceeding 50 μm are mixed, the fibers are considered to be non-ultrafine fibers and are excluded from the measurement of the average fiber diameter. Furthermore, when the ultrafine fibers have an irregular cross section, as described above, the cross-sectional area of the single fiber is first measured, and the diameter is calculated when the cross section is regarded as a circle, and the diameter of the single fiber is obtained. The average value of the matrix is calculated and regarded as the average single fiber diameter.

(2) Solidification temperature of aqueous dispersion 20 g of aqueous dispersion containing a polymer elastomer prepared in each example and comparative example was placed in a test tube with an inner diameter of 12 mm. After inserting a thermometer so that the tip was below the liquid surface, the test tube was sealed and 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 confirming the temperature rise in the test tube with the thermometer, the test tube was appropriately lifted up every 5 seconds to shake the liquid surface of the aqueous dispersion to the extent that the fluidity of the liquid surface of the aqueous dispersion could be confirmed. The temperature at which the liquid surface of the aqueous dispersion lost its fluidity was regarded as the solidification temperature. This measurement was performed 3 times for each type of aqueous dispersion, and the average value was calculated.

(3) Evaluation of the softness of sheet materials: According to the A method (45° cantilever method) described in 8.21.1 of 8.21 "Stiffness" of JIS L 1096:2010 "Test methods for grey fabrics of woven and knitted fabrics", 5 test pieces of 2×15 cm were made in the longitudinal direction and placed on a horizontal platform with a 45° inclined surface. The test pieces were slid and the scale was read when the center point of one end of the test piece touched the inclined surface. The average value of the 5 pieces was calculated.

(4) Evaluation of abrasion of sheet materials Abrasion evaluation was performed in accordance with JIS L 1096:2010. Model 406 manufactured by James H. Heal & Co. was used as the Martindale abrasion tester, and ABRASTIVE CLOTH SM25 manufactured by the same company was used as the standard abrasion cloth. A load of 12 kPa was applied to the sheet materials before and after the lightfastness test described below, and the number of abrasions was 20,000 times. The mass of the sheet materials before and after abrasion was used to calculate the abrasion loss using the following formula.

Wear loss (mg) = mass before wear (mg) - mass after wear (mg) In addition, the wear loss is the value rounded to the first decimal point.

(5) Light fastness test of sheet material: The light fastness test was carried out in accordance with JIS L 0843:2006 (method B, exposure method 5), and the exposure time was adjusted so that the xenon arc exposure amount became 110 MJ/ ^m2 .

(6) Identification of bonding types in polymer elastomers The polymer elastomer separated from the above-mentioned flakes was analyzed by infrared spectroscopy using FT/IR 4000 series manufactured by JASCO Corporation to identify the bonding types.

(7) L value retention rate The L value retention rate was measured and calculated by the above method using "CHP-250DN" manufactured by AS ONE Co., Ltd. as a hot plate and "CR-410" manufactured by Konica Minolta Co., Ltd. as a colorimeter.

(8) Determination of the type and content of inorganic salts contained in the sheet: The sheet was immersed in N,N-dimethylformamide overnight, and the solution containing the polymer elastomer and the inorganic salt was concentrated and solidified by heating and drying at 140°C. Distilled water was added to the obtained solid to dissolve only the inorganic salt. After the aqueous solution containing the inorganic salt was heated and dried, the amount of inorganic salt contained in the sheet was measured. In addition, the mass of the solidified polymer elastomer was measured after heating and drying, and the mass of the inorganic salt compared with the mass of the polymer elastomer was calculated. However, from the perspective of the validity of the value, less than 0.1 mass% compared with the polymer elastomer is regarded as less than the detection limit.

Regarding the type of the inorganic salt, the aqueous solution containing the inorganic salt was identified using an ion chromatograph "ICS-3000" manufactured by DIONEX.

[Manufacturing method of nonwoven fabric A for fiber substrate] SSIA (5-sodium sulfoisophthalate) 8 mol% copolymerized polyester is used as the sea component, polyethylene terephthalate is used as the island component, and the composite ratio of the sea component is 20% by mass and the island component is 80% by mass, so that the island-type composite fiber with an island number of 16 islands/1 filament and an average single fiber diameter of 20μm is obtained. The obtained island-type composite fiber is cut into short fibers with a fiber length of 51mm, and a fiber web is formed by a carding machine and a cross-stacking machine. By needle punching, a nonwoven fabric with a unit area weight of 700g/ ^m2 and a thickness of 3.0mm is manufactured. The nonwoven fabric thus obtained was immersed in hot water at a temperature of 98° C. for 2 minutes to shrink it, and then dried at a temperature of 100° C. for 5 minutes to prepare a nonwoven fabric A for a fiber substrate.

[Manufacturing method of nonwoven fabric B for fiber substrate] SSIA (5-sodium sulfoisophthalate) 8 mol% copolymerized polyester is used as the sea component, polyethylene terephthalate is used as the island component, and the composite ratio of the sea component is 43% by mass and the island component is 57% by mass, so that the island-type composite fiber with an island number of 16 islands/1 filament and an average single fiber diameter of 20μm is obtained. The obtained island-type composite fiber is cut into short fibers with a fiber length of 51mm, and a fiber web is formed by a carding machine and a cross-stacking machine. By needle punching, a nonwoven fabric with a unit area weight of 550g/ ^m2 and a thickness of 2.9mm is manufactured. The nonwoven fabric thus obtained was immersed in hot water at a temperature of 98° C. for 2 minutes to shrink it, and then dried at a temperature of 100° C. for 5 minutes to prepare a nonwoven fabric B for a fiber substrate.

[Production method of polymer elastomer] Polytetramethylene ether glycol (PTMG in the table) with a number average molecular weight (Mn) of 2,000 is used as the polyol, MDI is used as the isocyanate, and 2,2-dihydroxymethylpropionic acid is used as the component containing a hydrophilic group, and a prepolymer is prepared in a toluene solvent. Ethylene glycol and ethylenediamine as chain extenders, polyoxyethylene nonylphenyl ether as an external emulsifier, and water are added and stirred. The toluene is removed by decompression to obtain an aqueous dispersion of a polymer elastomer.

[Example 1] (Non-woven fabric) A non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Addition of polymer elastomer) 20 parts by mass of sodium sulfate (indicated as "Na ₂ SO ₄ " in Table 1) was added as a thermosensitive coagulant to 100 parts by mass of the polymer elastomer, and 3 parts by mass of a carbodiimide crosslinking agent was added, and the whole was adjusted to 12% by mass of solid content with water to obtain an aqueous dispersion containing a polymer elastomer. The thermosensitive coagulation temperature was 70°C. The obtained fiber base nonwoven fabric A was impregnated with the aforementioned aqueous dispersion, and then dried by hot air at a temperature of 160° C. for 20 minutes. When a sheet was prepared, the polymer elastic body was imparted in such a manner that the polymer elastic body accounted for 20% by mass in the 100% by mass sheet, thereby obtaining a nonwoven fabric imparted with a polymer elastic body having a thickness of 2.10 mm.

(Ultra-fine fiber development treatment) The obtained non-woven fabric endowed with a high molecular weight elastic body was immersed in a sodium hydroxide aqueous solution heated to 95°C and a concentration of 8g/L, and treated for 5 minutes to remove the sea component of the island-type composite fiber. Then, the sodium hydroxide aqueous solution attached to the non-woven fabric was immersed in water for 30 minutes and washed, and dried in a dryer at 160°C for 30 minutes to obtain a sheet containing ultra-fine fibers (sheet endowed with a high molecular weight elastic body).

(Dyeing and finishing) The obtained de-sealed sheet with the polymer elastomer was cut in half vertically in the thickness direction, and the opposite side of the cut side was polished with a 180-grit circular sandpaper to obtain a 0.75 mm thick sheet with fleece.

The obtained fluffy sheet is dyed with black dye at 120°C using a liquid jet dyeing machine. It is then dried in a dryer to obtain a sheet with an average single fiber diameter of 4.4μm of ultrafine fibers. The obtained sheet has a stiffness of 80mm, a wear loss of 7mg before the light resistance test, and a wear loss of 9mg after the light resistance test. It has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 93%, which has excellent heat resistance, and the amount of inorganic salts containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Example 2] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate is used as the non-woven fabric.

(Polymer elastic body addition) The thermosensitive coagulant was changed to sodium chloride (recorded as "NaCl" in Table 1). In addition, except for changing the amount of thermosensitive coagulant added, the heating temperature of the hot air, and the amount of polymer elastic body added, the same procedure as in Example 1 was performed to obtain a nonwoven fabric to which a polymer elastic body was added.

(Ultra-fine fiber revealing treatment) The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 90 mm, the abrasion loss before the light resistance test was 6 mg, and the abrasion loss after the light resistance test was 8 mg. It has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 91%, which has excellent heat resistance, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Example 3] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate is used as the non-woven fabric.

(Addition of polymer elastic body) Except for changing the addition amount of thermosensitive coagulant, the heating temperature of hot air, and the addition amount of polymer elastic body, the same procedure as in Example 1 was carried out to obtain a nonwoven fabric to which polymer elastic body was added.

(Ultra-fine fiber revealing treatment) The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 55 mm, the abrasion loss before the light resistance test was 12 mg, and the abrasion loss after the light resistance test was 18 mg. It has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 97%, which has excellent heat resistance, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Example 4] (Non-woven fabric) A non-woven fabric B for a fibrous substrate is used as the non-woven fabric.

(Polymer elastic body application) Except for changing the heating temperature of the hot air and the amount of polymer elastic body applied, the same procedure as in Example 2 was followed to obtain a nonwoven fabric with a thickness of 2.05 mm and with polymer elastic body applied.

(Ultra-fine fiber development treatment) The obtained non-woven fabric endowed with a high molecular weight elastic body was immersed in a sodium hydroxide aqueous solution heated to 95°C and a concentration of 8g/L for 10 minutes to remove the sea component of the island-type composite fiber. Then, the sodium hydroxide aqueous solution attached to the non-woven fabric was immersed in water for 30 minutes and washed, and dried in a dryer at 170°C for 30 minutes to obtain a sheet containing ultra-fine fibers (sheet endowed with a high molecular weight elastic body).

(Dyeing and finishing) The obtained de-sealed sheet with the polymer elastomer was cut in half vertically in the thickness direction, and the opposite side of the cut side was polished with a 120-grit circular sandpaper to obtain a 0.75 mm thick sheet with fluff.

The obtained fluffy sheet is dyed with black dye at 120°C using a liquid jet dyeing machine. It is then dried in a dryer to obtain a sheet with an average single fiber diameter of 3.0μm of ultrafine fibers. The obtained sheet has a stiffness of 75mm, a wear loss before the light resistance test of 7mg, and a wear loss after the light resistance test of 10mg. It has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 96%, which has excellent heat resistance, and the amount of inorganic salts containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Example 5] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate is used as the non-woven fabric.

(Addition of polymer elastic body) Except for changing the thermosensitive coagulant, the amount of the thermosensitive coagulant added, and the amount of the polymer elastic body added, the same procedure as in Example 1 was followed to obtain a nonwoven fabric to which the polymer elastic body was added.

(Ultra-fine fiber revealing treatment) The same process as in Example 1 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 100 mm, the abrasion loss before the light resistance test was 6 mg, and the abrasion loss after the light resistance test was 8 mg. It has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 94%, which has excellent heat resistance, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Example 6] (Non-woven fabric) Similar to Example 4, a non-woven fabric B for a fibrous substrate is used as the non-woven fabric.

(Provision of high molecular weight elastic body) The same procedure as in Example 4 was carried out to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber revealing treatment) The same process as in Example 4 is performed.

(Dyeing and finishing) The two sides of the de-sealed polymer elastomer sheet were polished with 180-grit circular sandpaper to obtain a 1.50 mm thick fleece-like sheet.

The obtained fleece-like sheet was dyed with black dye at 120°C using a jet dyeing machine. After drying in a dryer, it was cut in half vertically in the thickness direction to obtain a sheet of ultrafine fibers with an average single fiber diameter of 3.0 μm.

The stiffness of the obtained sheet is 80mm, the abrasion loss before the light resistance test is 6mg, and the abrasion loss after the light resistance test is 9mg, which has a soft feel and excellent light resistance and abrasion resistance. In addition, N-acyl urea bonds and isourea bonds exist inside the polymer elastomer. Furthermore, the L value retention rate is 96%, which has excellent heat resistance, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer is less than the detection limit.

[Comparative Example 1] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

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

[Comparative Example 2] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Addition of high molecular weight elastic body) Except for changing the amount of the thermosensitive coagulant added, the same procedure as in Example 1 was carried out to obtain a nonwoven fabric to which a high molecular weight elastic body was added.

(Ultra-fine fiber revealing treatment) The same process as in Example 1 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. Since the stiffness of the obtained sheet was greater than 150 mm, it could not be measured and had a hard feel. The abrasion loss before the light resistance test was 15 mg, and the abrasion loss after the light resistance test was 25 mg. In addition, N-acyl urea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 87%, and the heat resistance was insufficient. The amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 3] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Addition of high molecular weight elastic body) Except for changing the amount of the thermosensitive coagulant added, the same procedure as in Example 1 was carried out to obtain a nonwoven fabric to which a high molecular weight elastic body was added.

(Ultra-fine fiber revealing treatment) The same process as in Example 1 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. Since the stiffness of the obtained sheet was greater than 150 mm, it could not be measured and had a hard feel. The abrasion loss before the light resistance test was 16 mg, and the abrasion loss after the light resistance test was 28 mg, indicating poor light resistance. In addition, N-acyl urea bonds and isourea bonds were present inside the polymer elastomer. Furthermore, the L value retention rate was 89%, indicating insufficient heat resistance, and the amount of inorganic salts containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 4] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Provision of a high molecular weight elastic body) The same procedure as in Example 2 was followed except that no crosslinking agent was provided to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber revealing treatment) The same process as in Example 2 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. Since the stiffness of the obtained sheet was greater than 150 mm, it could not be measured and had a hard feel. The abrasion loss before the light resistance test was 21 mg, and the abrasion loss after the light resistance test was 32 mg, indicating that the light resistance and abrasion resistance were inferior. In addition, there were no N-acylurea bonds and isourea bonds inside the polymer elastomer. Furthermore, the L value retention rate was 88%, indicating that the heat resistance was insufficient, and the amount of inorganic salts containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 5] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Provision of high molecular weight elastic body) Except for changing the heating temperature, the same procedure as in Example 1 was carried out to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber revealing treatment) The same process as in Example 1 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 120 mm, the abrasion loss before the light resistance test was 13 mg, and the abrasion loss after the light resistance test was 29 mg, indicating that the light resistance was inferior. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 88%, indicating that the heat resistance was insufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 6] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Provision of high molecular weight elastic body) The same procedure as in Example 1 was carried out to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber revealing treatment) The same procedure as Example 1 was followed except that the drying temperature was changed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 130 mm, the abrasion loss before the light resistance test was 16 mg, and the abrasion loss after the light resistance test was 30 mg, indicating that the light resistance was inferior. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 88%, indicating that the heat resistance was insufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 7] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Addition of polymer elastomer) 3 parts by mass of carbodiimide crosslinking agent was added to 100 parts by mass of polymer elastomer, and nonionic thickener (guar gum) ["Neosoft G" manufactured by Sun Chemical Co., Ltd.] was added in such a manner that the effective ingredient was 1 part by mass to 100 parts by mass of polymer elastomer, and the whole was adjusted to 13% by mass of solid content with water to obtain an aqueous dispersion containing polymer elastomer. The obtained nonwoven fabric was immersed in the aforementioned 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. When a sheet was made, a polymer elastic body was imparted in such a manner that the polymer elastic body accounted for 20% by mass in 100% by mass of the sheet, thereby obtaining a nonwoven fabric imparted with a polymer elastic body having a thickness of 2.10 mm.

(Ultra-fine fiber revealing treatment) The same process as in Example 1 is performed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 90 mm, the abrasion loss before the light resistance test was 20 mg, and the abrasion loss after the light resistance test was 33 mg, indicating that the light resistance and abrasion resistance were inferior. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 87%, indicating that the heat resistance was insufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 8] (Non-woven fabric) Similar to Example 1, a non-woven fabric A for a fibrous substrate was used as the non-woven fabric.

(Provision of a high molecular weight elastic body) The same procedure as in Example 2 was followed except that no crosslinking agent was provided to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber development treatment) The obtained nonwoven fabric endowed with polymer elastomer was immersed in a sodium hydroxide aqueous solution heated to 95°C and at a concentration of 8g/L, and treated for 5 minutes to remove the sea component of the island-type composite fiber. Then, the sodium hydroxide aqueous solution attached to the nonwoven fabric was immersed in water and washed for 30 minutes, and dried in a 120°C dryer for 30 minutes. Then, water was added to the carbodiimide crosslinking agent, and the whole was adjusted to a solid content of 2% by mass. The crosslinking agent was impregnated and imparted to the sheet, and dried in a 160°C dryer for 30 minutes to obtain a sheet containing ultra-fine fibers (sheet endowed with polymer elastomer).

(Dyeing and finishing) The same procedure as in Example 1 was performed. Since the stiffness of the obtained sheet was greater than 150 mm, it could not be measured and had a hard feel. The abrasion loss before the light resistance test was 20 mg, and the abrasion loss after the light resistance test was 30 mg, indicating that the light resistance and abrasion resistance were inferior. In addition, N-acylurea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 86%, indicating that the heat resistance was insufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Comparative Example 9] (Non-woven fabric) Similar to Example 4, a non-woven fabric B for a fiber substrate was used as the non-woven fabric.

(Provision of high molecular weight elastic body) The above nonwoven fabric was impregnated with a 10 mass % aqueous solution of PVA (NM-14 manufactured by Nippon Gosei Kagaku Co., Ltd.) having a saponification degree of 99% and a polymerization degree of 1400, and heat-dried at 140°C for 10 minutes to obtain a sheet provided with PVA having an attachment amount of 30 mass parts of PVA relative to 100 mass parts of the fiber mass of the nonwoven fabric for the fiber substrate.

The obtained PVA-imparted sheet was immersed in an aqueous sodium hydroxide solution having a concentration of 8 g/L heated to 95°C for 30 minutes to obtain a sheet containing ultrafine fibers (UV-imparted ultrafine fiber nonwoven fabric) after removing the sea component of the sea-island type composite fibers.

15 parts by mass of sodium chloride (indicated as "NaCl" in Table 1) was added as a thermosensitive coagulant to 100 parts by mass of the polymer elastomer, and 3 parts by mass of a carbodiimide crosslinking agent was added, and the whole was adjusted to 12% by mass of solid content by water to obtain an aqueous dispersion containing a polymer elastomer. The thermosensitive coagulation temperature was 68°C. The obtained fibrous substrate nonwoven fabric A was impregnated in the aforementioned aqueous dispersion, and then dried by hot air at a temperature of 160°C for 20 minutes. When a sheet was made, the polymer elastomer was imparted in such a manner that the polymer elastomer was 38% by mass in 100% by mass of the sheet, and a sheet imparted with a polymer elastomer having a thickness of 2.05 mm was obtained.

The obtained sheet endowed with the polymer elastomer was immersed in water heated to 95°C for 10 minutes, and dried in a dryer at 120°C for 30 minutes to obtain a sheet from which the endowed PVA was removed.

(Dyeing and finishing) The same procedure as in Example 1 was performed. The stiffness of the obtained sheet was 90 mm, the abrasion loss before the light resistance test was 11 mg, and the abrasion loss after the light resistance test was 26 mg, indicating that the light resistance was inferior. In addition, N-acyl urea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 91%, indicating excellent heat resistance, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was 1.2 mass %.

[Comparative Example 10] (Non-woven fabric) Similar to Example 6, a non-woven fabric B for a fiber substrate was used as the non-woven fabric.

(Provision of high molecular weight elastic body) Except for changing the heating temperature, the same procedure as in Example 6 was carried out to obtain a nonwoven fabric provided with a high molecular weight elastic body.

(Ultra-fine fiber revealing treatment) The same procedure as Example 6 was followed except that the drying temperature was changed.

(Dyeing and finishing) The same procedure as in Example 6 was performed. The stiffness of the obtained sheet was 85 mm, the abrasion loss before the light resistance test was 21 mg, and the abrasion loss after the light resistance test was 31 mg, and the light resistance and abrasion resistance were inferior. In addition, N-acyl urea bonds and isourea bonds existed inside the polymer elastomer. Furthermore, the L value retention rate was 85%, the heat resistance was insufficient, and the amount of inorganic salt containing monovalent cations inside the polymer elastomer was less than the detection limit.

[Table 1] Aqueous dispersion containing a high molecular weight elastic body having a hydrophilic group Processing conditions Thermal Coagulant Crosslinking agent Polymer elastomer imparting step Drying step Type Added amount (weight) Heating temperature(℃) Drying temperature(℃) Embodiment 1 _{Na2SO4 ​} 20 Carbodiimide series 160 160 Embodiment 2 NaCl 15 Carbodiimide series 150 155 Embodiment 3 _{Na2SO4 ​} 15 Carbodiimide series 170 170 Embodiment 4 NaCl 15 Carbodiimide series 160 170 Embodiment 5 NaCl 40 Carbodiimide series 160 160 Embodiment 6 NaCl 15 Carbodiimide series 160 170 Comparison Example 1 MgSO ₄ 10 Carbodiimide series - - Comparison Example 2 _{Na2SO4 ​} 1 Carbodiimide series 160 160 Comparison Example 3 _{Na2SO4 ​} 55 Carbodiimide series 160 160 Comparison Example 4 NaCl 15 - 150 155 Comparison Example 5 _{Na2SO4 ​} 20 Carbodiimide series 110 160 Comparison Example 6 _{Na2SO4 ​} 20 Carbodiimide series 160 110 Comparative Example 7 - - Carbodiimide series 160 160 Comparative Example 8 NaCl 15 - 150 160 Comparative Example 9 NaCl 15 Carbodiimide series 160 - Comparative Example 10 NaCl 15 Carbodiimide series 110 110

[Table 2] Average single fiber diameter (μm) PU content (mass%) Presence of N-acylurea bond/isourea bond Stiffness(mm) Wear loss (mg) L value retention rate (%) Before light fastness test After light fastness test Embodiment 1 4.4 20 have 80 7 9 93 Embodiment 2 4.4 30 have 90 6 8 91 Embodiment 3 4.4 16 have 55 12 18 97 Embodiment 4 3.0 38 have 75 7 10 96 Embodiment 5 4.4 32 have 100 6 8 94 Embodiment 6 3.0 38 have 80 6 9 96 Comparison Example 1 - - - - - - - Comparison Example 2 4.4 20 have > 150 15 25 87 Comparison Example 3 4.4 20 have > 150 16 28 89 Comparison Example 4 4.4 30 without > 150 twenty one 32 88 Comparison Example 5 4.4 20 have 120 13 29 88 Comparison Example 6 4.4 20 have 130 16 30 88 Comparative Example 7 4.4 20 have 90 20 33 87 Comparative Example 8 4.4 20 without > 150 20 30 86 Comparative Example 9 3.0 38 have 90 11 26 91 Comparative Example 10 3.0 38 have 85 twenty one 31 85

Furthermore, "PU" in Table 2 stands for polyurethane. [Possibility of industrial application]

The sheet material obtained by the present invention can be used as a surface material for furniture, chairs and wall materials, or seats, ceilings and interiors of vehicles such as cars, trains and aircraft, interior materials with very beautiful appearance, uppers and decorations of shirts, jackets, casual shoes, sports shoes, gentlemen's shoes and women's shoes, bags, belts, wallets, etc., and industrial materials such as clothing materials for a part of them, wiping cloths, polishing cloths and CD covers.

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Claims (8)

A sheet-like article, which is a sheet-like article containing a polymer elastic body in a fiber base material, wherein the fiber base material comprises ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastic body has a hydrophilic group and contains polyether glycol as a constituent component, and has N-acyl urea bonds and/or isourea bonds inside the polymer elastic body, and the sheet-like article satisfies the following conditions 1 and 2: Condition 1: the stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L 1096:2010 "Test methods for grey fabrics of woven and knitted fabrics" is 40 mm or more and 140 mm or less, and Condition 2: the stiffness in the longitudinal direction specified by the A method (45° cantilever method) described in JIS L 0843:2006 Light fastness test method: after the light fastness test is carried out at a xenon arc dose of 110MJ/ ^m2 , the abrasion loss after 20,000 times of the Martindale abrasion test specified in JIS L 1096:2005 is less than 25mg. For the sheet material in claim 1, the wear loss after 20,000 Martindale abrasion tests specified in JIS L 1096:2010 is less than 20 mg before the light resistance test. The sheet material of claim 1 or 2 contains more than 10% by mass of the polymer elastic body. The sheet of claim 1 or 2, wherein the sheet further satisfies the following condition 3; Condition 3: When the napped surface of the sheet is placed on a hot plate heated to 150°C and pressed for 10 seconds at a pressure load of 2.5 kPa, the retention rate of the L value is 90% or more and 100% or less. A method for manufacturing a sheet-like article, which comprises the following steps (1) to (4) in sequence: (1) a polymer elastic body impregnation step, which is to impregnate a fibrous substrate containing ultrafine fiber-developing fibers with a water dispersion containing a polymer elastic body, an inorganic salt containing monovalent cations, and a crosslinking agent, and then heat-treat the polymer elastic body at a temperature of 120°C to 180°C, wherein the polymer elastic body has a hydrophilic group and contains polyether glycol as a constituent component, The content of the inorganic salt containing monovalent cations in the aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the high molecular weight elastic body; (2) an ultrafine fiber development step, which is to treat the ultrafine fiber development type fiber with alkali to develop the ultrafine fibers; (3) a drying step, which is to apply heat treatment at a temperature of 120°C to 180°C; (4) a raising step, which is to raise at least one side of the unraised sheet to form fluff on the surface. The method for manufacturing a sheet material as claimed in claim 5, wherein after the drying step, a dyeing step of a non-fluffed sheet material or a fluffed sheet material is included. The method for manufacturing a sheet as claimed in claim 5 or 6, wherein the inorganic salt containing monovalent cations is sodium chloride and/or sodium sulfate. A method for manufacturing a sheet as claimed in claim 5 or 6, wherein the crosslinking agent is a carbodiimide crosslinking agent.