JP7322573B2 - Sheet-shaped article and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sheet-like article and its manufacturing method, and particularly preferably to a sheet-like article having a napped layer and its manufacturing method.

A sheet-like material mainly composed of a fibrous base material such as a non-woven fabric and polyurethane has excellent characteristics not found in natural leather, and is widely used for various purposes such as artificial leather. In particular, sheet-like materials using polyester-based fibrous base materials are excellent in light resistance, and their use has been expanding year by year for clothing, chair upholstery, automobile interior materials, and the like.

In producing such a sheet material, the fibrous base material is impregnated with an organic solvent solution of polyurethane, and then the obtained fibrous base material is immersed in water or an aqueous solution of an organic solvent, which is a non-solvent for polyurethane. A combination of steps to wet coagulate the polyurethane is commonly employed. In this case, a water-miscible organic solvent such as N,N-dimethylformamide (hereinafter also referred to as "DMF") is used as the organic solvent for the polyurethane. However, since organic solvents are generally highly harmful to the human body and the environment, there is a strong demand for methods that do not use organic solvents in the production of sheet materials.

As a specific solution, a method of using water-dispersed polyurethane, in which polyurethane resin is dispersed in water, instead of conventional organic solvent-based polyurethane, has been investigated. Until now, in order to obtain a sheet-like material with a soft texture using a water-dispersed polyurethane, for example, a water-dispersed polyurethane liquid containing a foaming agent was applied to a fibrous base material such as a sheet made of a fabric such as a nonwoven fabric. A method has been proposed in which a gas is generated in the polyurethane by applying it and heating to make the structure of the polyurethane in the fibrous base material a porous structure (see Patent Document 1).

In addition, a fibrous base material is impregnated in a solution containing a water-dispersed polyurethane and a thickener, and then immersed in hot water to reduce the size of the polyurethane resin and increase the gripping force of the entangled portions of the fibers by the water-dispersed polyurethane. A method for lowering it has been proposed (see Patent Document 2).

Japanese Unexamined Patent Application Publication No. 2011-214210 WO2015/129602

However, there is a problem that a sheet-like material obtained by impregnating a fibrous base material with a water-dispersed polyurethane dispersion in which a water-dispersed polyurethane is dispersed and solidifying the polyurethane tends to have a hard texture.

One of the main reasons for this is the difference in coagulation methods between the two. That is, the coagulation method of the organic solvent-based polyurethane liquid is the so-called wet coagulation method, in which the polyurethane molecules dissolved in the organic solvent are solidified by replacing the solvent with water. is formed. Therefore, even when the polyurethane is impregnated into the fibrous base material and solidified, the adhesive area between the fiber and the polyurethane is reduced, resulting in a soft sheet-like material.

On the other hand, water-dispersed polyurethane is mainly coagulated by a so-called wet heat coagulation method, in which the water-dispersed polyurethane dispersion is coagulated by heating to collapse the hydration state of the water-dispersed polyurethane dispersion, and the polyurethane emulsion is aggregated. The resulting polyurethane membrane structure results in a dense, non-porous membrane. As a result, the fibrous base material and the polyurethane are tightly adhered to each other, and the entangled portions of the fibers are strongly held, resulting in a hard texture.

In the method disclosed in Patent Document 1, by making the water-dispersed polyurethane porous, the adhesive area between the fibers and the polyurethane is reduced, the gripping force at the intertwined points of the fibers is weakened, and the texture is soft and favorable. Although it is possible to obtain a sheet-like material having a texture, it still tends to be less flexible than when an organic solvent-based polyurethane is applied.

On the other hand, in the method disclosed in Patent Document 2, by making the water-dispersed polyurethane porous, the adhesion area between the fiber and the polyurethane is reduced, the gripping force at the entangled points of the fiber is weakened, and the touch is soft. However, since the divalent cation-containing inorganic salt is used as the heat-sensitive coagulation modifier, there is a problem of uneven impregnation due to gelation of the impregnating liquid.

Accordingly, in view of the background of the prior art described above, an object of the present invention is to provide a sheet-like material having good surface quality, glossiness and texture, and a method for producing the same.

In order to solve the above problems, the present invention has the following configurations. That is, the sheet-like material of the present invention is a sheet-like material containing a fibrous base material and an elastic polymer, and the fibrous base material is ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less. The elastic polymer has a hydrophilic group and an N-acylurea bond and/or an isourea bond, and has a thickness of 500 μm including 500 or more microfiber cross-sections in a cross-section obtained by cutting the sheet-like material in the thickness direction. A macromolecular elastic body having a length of 10 μm or more from the bonding portion with the ultrafine fiber in four directions, and a maximum width of 0 μm or less and 5 μm or less at the portion within 10 μm from the bonding portion with the ultrafine fiber. The number is 20 or more.

Further, the method for producing the sheet-shaped material of the present invention is a method for producing the sheet-shaped material of the present invention, comprising the step of impregnating a fibrous base material with an aqueous dispersion, a step of performing coagulation treatment by an acid coagulation method in which coagulation treatment is performed with water or a hot water coagulation method in which coagulation treatment is performed in hot water of 80 to 100 ° C., and a step of drying at 100 to 180 ° C., The fibrous base material is made of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion comprises an elastic polymer having a hydrophilic group, a cross-linking agent, and an elastic polymer having a hydrophilic group. Contains 10 parts by mass or more and 50 parts by mass or less of monovalent cation-containing inorganic salt and a thickener per 100 parts by mass of body solids.

According to a preferred aspect of the sheet-shaped article of the present invention, the number of the polymeric elastic bodies is 30 or more.

According to a preferred embodiment of the sheet-like article of the present invention, it has a napped layer, and the surface coverage of the ultrafine fibers in the napped layer is 60% or more and 90% or less.

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

According to a preferred aspect of the method for producing a sheet-like material of the present invention, the thickener is a nonionic thickener.

According to the present invention, it is possible to obtain a sheet-like material having an elegant surface quality, glossiness and good texture.

1 is an example of a cross-sectional microscopic photograph of a bonding portion between an elastic polymer and a fiber in the sheet-like material of the present invention. FIG. 3 is a conceptual diagram showing an example of a method for defining a thread-like elastic polymer in the sheet-like material of the present invention. FIG. 4 is a conceptual diagram showing another example of a method for defining a thread-like elastic polymer in the sheet-like article of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual perspective view which illustrates the evaluation method of the surface quality of the sheet-like article which concerns on this invention.

The sheet-like material of the present invention is a sheet-like material containing a fibrous base material and an elastic polymer, wherein the fibrous base material is made of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less. , The polymeric elastic body has a hydrophilic group and an N-acylurea bond and/or an isourea bond, and has a 500 μm square area containing 500 or more ultrafine fiber cross-sections in a cross section obtained by cutting the sheet in the thickness direction. In the range, the length from the bonding portion with the ultrafine fiber is 10 μm or more, and the maximum width of the portion within 10 μm from the bonding portion with the ultrafine fiber exceeds 0 μm and the maximum width is 5 μm or less. 20 or more. Although these constituent elements will be described in detail below, the present invention is not limited to the scope described below as long as it does not exceed the gist of the present invention.

[Ultrafine fiber]
Polyester-based resins obtained from dicarboxylic acids and/or ester-forming derivatives thereof and diols, that is, resins such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate can be used for the ultrafine fibers used in the present invention. can.

Dicarboxylic acids and/or ester-forming derivatives thereof used in the polyester resin include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and ester-forming derivatives thereof. is mentioned. The term "ester-forming derivatives" as used in the present invention includes lower alkyl esters of dicarboxylic acids, acid anhydrides and acyl chlorides. Specifically, methyl ester, ethyl ester, hydroxyethyl ester and the like are preferably used. A more preferred embodiment of the dicarboxylic acid and/or its ester-forming derivative used in the present invention is terephthalic acid and/or its dimethyl ester.

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

In addition, the polyester-based resin can contain additives such as particles such as metal oxides and pigments, flame retardants, and antistatic agents, which are commonly used, as long as the effects of the present invention are not impaired.

The cross-sectional shape of the ultrafine fibers may be a circular cross-section, but may also be elliptical, flat, polygonal such as triangular, or irregular cross-sections such as fan-shaped or cross-shaped.

In the present invention, it is important that the average single fiber fineness of the ultrafine fibers is 0.1 μm or more and 10 μm or less. When the average single fiber fineness of the ultrafine fibers is 10 µm or less, preferably 7 µm or less, and more preferably 5 µm or less, the sheet-like material can be made more flexible. Moreover, when the sheet-like material has naps, the surface quality of the naps can be improved. On the other hand, when the average single fiber fineness of the ultrafine fibers is 0.1 μm or more, preferably 0.3 μm or more, and more preferably 0.7 μm or more, a sheet-like article having excellent color developability after dyeing can be obtained. . In addition, when the sheet-like material has naps, it is possible to improve the easiness of dispersing and separating the ultrafine fibers present in bundles when performing the nap treatment by buffing.

The average single fiber fineness referred to in the present invention is measured by the following method. i.e.
(1) Observe a cross section of the sheet material cut in the thickness direction with a scanning electron microscope (SEM).
(2) Measure the fiber diameter of any 50 microfibers in the observation plane in three directions on each microfiber cross section. However, when ultrafine fibers with irregular cross-sections are used, the cross-sectional area of the single fiber is first measured, and the diameter of the circle corresponding to the cross-sectional area is calculated by the following formula. The diameter thus obtained is taken as the single fiber diameter of the single fiber.
・Single fiber diameter (μm)=(4×(cross-sectional area of single fiber (μm ² ))/π) ^1/2
(3) Calculate the arithmetic mean value (μm) of the obtained total of 150 points and round off to the second decimal place.

As means for obtaining the ultrafine fibers used in the present invention, direct spinning and ultrafine fiber development type fibers can be used. Among them, it is a preferred embodiment to use ultrafine fibers. The ultrafine fiber-developing type fiber is a sea-island type, in which two thermoplastic resins with different solubilities in solvents are used as a sea component and an island component, and only the sea component is dissolved and removed using a solvent or the like to make the island component into an ultrafine fiber. Composite fibers, exfoliation-type conjugate fibers or multi-layer conjugate fibers, etc., in which two-component thermoplastic resins are arranged alternately in a radial or layered fiber cross-section and split into ultrafine fibers by peeling and splitting each component. However, islands-in-the-sea type conjugate fibers are preferably used because the surface quality of the sheet can be easily made uniform.

Examples of the sea component of the sea-island composite fiber include polyolefins such as polyethylene and polypropylene, polystyrene, copolymer polyester obtained by copolymerizing sodium sulfoisophthalate and polyethylene glycol, polylactic acid, polyvinyl alcohol, and copolymers thereof. be done.

The ultra-fine fiber treatment (sea removal treatment) of the islands-in-the-sea composite fiber can be performed by immersing the islands-in-the-sea composite fiber in a solvent and squeezing the solvent. As the solvent for dissolving the sea component, organic solvents such as toluene and trichlorethylene, alkaline aqueous solutions such as sodium hydroxide, and hot water can be used.

Apparatuses such as a continuous dyeing machine, a vibrowasher type deseaming machine, a jet dyeing machine, a wince dyeing machine and a jigger dyeing machine can be used for the ultrafine fiber treatment.

The dissolution and removal of the sea component can be performed at any timing before or after application of the elastic polymer. If the sea-removing treatment is performed before imparting the elastic polymer, a structure in which the elastic polymer directly adheres to the ultrafine fibers is formed, and the ultrafine fibers can be strongly gripped, so that the abrasion resistance of the sheet-like article is improved. On the other hand, if the sea component is removed after imparting the elastic polymer, voids are formed between the elastic polymer and the ultrafine fibers due to the sea components that have been removed. The texture of the sheet material becomes softer without being gripped.

The mass ratio of the sea component and the island component in the sea-island composite fiber used in the present invention is preferably in the range of sea component:island component=10:90 to 80:20. When the mass ratio of the sea component is 10% by mass or more, the island component tends to be sufficiently ultrafine. Moreover, when the mass ratio of the sea component is 80 mass or less, the productivity is improved because the ratio of the eluted component is small. The mass ratio of the sea component and the island component is more preferably in the range of sea component:island component=20:80 to 70:30.

In the present invention, when drawing ultrafine fibers represented by sea-island composite fibers, the undrawn yarn is once wound and then drawn separately, or the undrawn yarn is taken off and continuously drawn. Any method can be adopted, such as performing The stretching can be appropriately carried out by a method of one to three stages of stretching with wet heat, dry heat, or both. Next, the stretched islands-in-the-sea composite fiber is preferably crimped and cut into a predetermined length to obtain raw cotton for a nonwoven fabric. A normal method can be used for crimping and cutting.

The conjugate fibers such as the islands-in-the-sea type conjugate fibers used in the present invention are preferably provided with buckling crimps. This is because the buckling crimp improves the entangling property between fibers in the case of forming a short fiber nonwoven fabric, and enables high density and high entangling. A normal stuffing box type crimper is preferably used to impart buckling crimps to the conjugate fiber. It is a preferred embodiment to appropriately adjust the pressing pressure and the like.

The crimp retention factor of the buckling-crimped ultrafine fibers is preferably in the range of 3.5 to 15, more preferably in the range of 4 to 10. When the crimp retention factor is 3.5 or more, the rigidity in the thickness direction of the nonwoven fabric is improved when the nonwoven fabric is formed, and the entangling property in the entangling process such as needle punching can be maintained. Further, by setting the crimp retention factor to 15 or less, the fiber web is excellent in openability in carding without being excessively crimped.

The crimp retention factor referred to here is represented by the following formula.
・Crimp retention factor = (W/L-L ₀ ) ^1/2
・W: crimp disappearance load (load when crimp is completely stretched: mg/dtex)
・L: Fiber length (cm) under crimp disappearance load
・L0: Fiber length (cm) under 6 mg/dtex. Mark 30.0 cm.

As a measuring method, first, a load of 100 mg/dtex is applied to the sample, and then the load is increased in 10 mg/dtex increments to confirm the crimp state. A load is applied until the crimp is completely stretched, and the length of the marking (elongation from 30.0 cm) is measured when the crimp is completely stretched.

The single fiber fineness of the conjugate fiber used in the present invention is preferably in the range of 2 dtex or more and 10 dtex or less, more preferably 3 dtex or more and 9 dtex or less, from the viewpoint of entanglement in a needle punching process or the like.

The conjugate fiber that can be used in the method for producing a sheet-like article of the present invention preferably has a shrinkage rate of 5% to 40% at a temperature of 98° C., more preferably 10% to 35%. By setting the shrinkage ratio within this range, the fiber density can be improved by the hot water treatment, and a feeling of fullness similar to that of genuine leather can be obtained.

Specifically, the contraction rate is measured by first applying a load of 50 mg/dtex to the composite fiber bundle and marking 30.0 cm (L ₀ ). Then, it is treated in hot water at a temperature of 98° C. for 10 minutes, the length (L ₁ ) before and after treatment is measured, and (L ₀ −L ₁ )/L ₀ ×100 is calculated. The measurement is performed three times, and the average value is taken as the shrinkage rate.

In the present invention, the number of fibers in the ultrafine fiber bundle is preferably 8 to 1000/bundle, more preferably 10 to 800/bundle. When the number of fibers is 8 or more per bundle, the ultrafine fibers tend to have sufficient density, and mechanical properties such as wear tend to be improved. Further, when the number of fibers is 1000/bundle or less, the opening property at the time of nap improves, and the fiber distribution on the nap surface becomes uniform, making it easier to obtain a better surface quality of the sheet.

[Fibrous base material]
The fibrous base material used in the present invention comprises the ultrafine fibers. It should be noted that the fibrous base material may be mixed with ultrafine fibers of different raw materials.

As a specific form of the fibrous base material, a nonwoven fabric formed by entangling each of the ultrafine fibers or a nonwoven fabric formed by entangling fiber bundles of ultrafine fibers can be used. Among them, a nonwoven fabric in which fiber bundles of ultrafine fibers are entangled is preferably used from the viewpoint of the strength and texture of the sheet-like article. From the viewpoint of softness and texture, it is particularly preferable to use a nonwoven fabric in which the ultrafine fibers constituting the fiber bundle of the ultrafine fibers are appropriately separated from each other to form voids. Thus, a nonwoven fabric in which fiber bundles of ultrafine fibers are entangled can be obtained, for example, by previously entangling ultrafine fiber developing type fibers and then developing ultrafine fibers. In addition, nonwoven fabrics in which microfibers constituting a fiber bundle of ultrafine fibers are spaced apart appropriately to form voids are, for example, sea-island composite fibers in which voids can be formed between island components by removing the sea component. can be obtained by using

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

In a preferred embodiment, the fiber length of the short fibers in the case of using the short fiber nonwoven fabric is in the range of 25 mm or more and 90 mm or less. When the fiber length is 25 mm or more, preferably 35 mm or more, and even more preferably 40 mm or more, a sheet-like material having excellent abrasion resistance can be obtained by entanglement. Further, when the fiber length is 90 mm or less, more preferably 80 mm or less, and even more preferably 70 mm or less, a sheet-like material having excellent texture and surface quality can be obtained.

In the present invention, when a nonwoven fabric is used as the fibrous base material, a woven fabric or a knitted fabric may be inserted, laminated, or lined inside the nonwoven fabric for the purpose of improving strength. The average single fiber fineness of the fibers constituting such a woven fabric or knitted fabric is more preferably 0.3 μm or more and 10 μm or less because damage during needle punching can be suppressed and strength can be maintained.

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

Methods for obtaining a nonwoven fabric that can be used as the fibrous base material constituting the sheet-shaped article of the present invention include a method of entangling a composite fiber web by needle punching or water jet punching, a spunbonding method, a meltblowing method, and a papermaking method. Laws, etc. can be adopted. Among them, a method of undergoing processing such as needle punching or water jet punching is preferably used in order to form the ultrafine fiber bundle as described above.

As described above, the nonwoven fabric may be formed by laminating and integrating a nonwoven fabric and a woven or knitted fabric, and a method of integrating these by needle punching, water jet punching, or the like is preferably used.

In the needle used for needle punching, the number of needle barbs (notches) is preferably 1 or more and 9 or less. Efficient entanglement of fibers becomes possible by preferably using one or more needle barbs. On the other hand, fiber damage can be suppressed by preferably setting the number of needle barbs to 9 or less.

The number of conjugate fibers caught on a barb is determined by the shape of the barb and the diameter of the conjugate fiber. Therefore, the barb shape of the needle used in the needle punching process has a kick-up of 0 μm or more and 50 μm or less, an undercut angle of 0° or more and 40° or less, a throat depth of 40 μm or more and 80 μm or less, and a throat length of 0° or more and 40° or less. is preferably 0.5 mm or more and 1.0 mm or less.

Moreover, the punching number is preferably 1000/cm ² or more and 8000/cm ² or less. By setting the punching number to preferably 1000/cm ² or more, denseness can be obtained and highly accurate finishing can be obtained. On the other hand, by setting the punching number to preferably 8000/cm ² or less, it is possible to prevent deterioration of workability, fiber damage, and reduction in strength.

Further, when water jet punching is performed, it is preferable to use water in the form of a columnar flow. Specifically, in a preferred embodiment, water is ejected from a nozzle having a diameter of 0.05 mm or more and 1.0 mm or less at a pressure of 1 MPa or more and 60 MPa or less.

The apparent density of the nonwoven fabric after needle punching or water jet punching is preferably 0.15 g/cm ³ or more and 0.45 g/cm ^{3 or} less. By setting the apparent density to preferably 0.15 g/cm ³ or more, the sheet-like material can easily obtain sufficient shape stability and dimensional stability. On the other hand, when the apparent density is preferably 0.45 g/cm ³ or less, a sufficient space for applying polyurethane can be easily maintained.

From the viewpoint of densification, the nonwoven fabric thus obtained is preferably shrunk by dry heat, wet heat, or both, and further densified. The nonwoven fabric can also be compressed in the thickness direction by calendering or the like.

When sea-island composite fibers are used, the sea removal treatment for removing the sea component of the fibers is performed before applying an aqueous dispersion containing an elastic polymer having a hydrophilic group to the fibrous base material and/or Can be done after giving. If the sea removal treatment is performed before applying the aqueous dispersion, the structure in which the polymer elastic body is likely to adhere directly to the ultrafine fibers is likely to be formed, and the ultrafine fibers can be strongly gripped, thereby improving the abrasion resistance of the sheet-like material.

On the other hand, by applying an inhibitor such as a cellulose derivative or polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) to the ultrafine fibers before applying the aqueous dispersion, and then applying the aqueous dispersion, the ultrafine fibers and the high The adhesiveness of the molecular elastic resin can be lowered, and a softer touch can be achieved.

The inhibitor may be applied either before or after the sea-island structure fiber is treated to remove the sea. By adding the inhibitor before the sea removal treatment, the shape retention force of the fibrous base material can be increased even when the basis weight of the fibers is lowered and the tensile strength of the sheet is lowered. Therefore, thin sheets can be stably processed, and the thickness retention rate of the fibrous base material in the sea removal process can be increased, thereby suppressing an increase in the density of the fibrous base material. On the other hand, by applying the inhibitor after the sea removal treatment, it is possible to increase the density of the fibrous base material.

As the inhibitor, since the reinforcing effect of the fibrous base material is high and it is difficult to dissolve in water,
PVA is preferably used. Among PVA, PVA is more resistant to water from the viewpoint that inhibitors are less likely to be eluted when an aqueous dispersion containing an elastic polymer having a hydrophilic group is applied, and adhesion between ultrafine fibers and the elastic polymer can be further inhibited. Applying a certain high degree of saponification PVA is a more preferred embodiment.

The high saponification degree PVA preferably has a saponification degree of 95% or more and 100% or less, more preferably 98% or more and 100% or less. By adjusting the degree of saponification to 95% or more, it is possible to suppress elution at the time of application of the elastic polymer dispersion having a hydrophilic group.

The degree of polymerization of PVA is preferably 500 or more and 3500 or less, more preferably 500 or more and 2000 or less. By setting the degree of polymerization of PVA to 500 or more, it is possible to suppress the elution of PVA with a high degree of saponification when the elastic polymer dispersion is applied. Further, by setting the degree of polymerization of PVA to 3500 or less, the viscosity of the high saponification degree PVA liquid does not become too high, and the high saponification degree PVA can be stably applied to the fibrous base material.

The amount of PVA applied to the fibrous base material is 0.1% by mass or more and 50% by mass or less, preferably 1% by mass or more and 45% by mass or less based on the fiber mass of the fibrous base material. When the amount of PVA added is 0.1% by mass or more, a sheet-like material with good flexibility and texture can be obtained. A sheet having good physical properties such as abrasion resistance can be obtained.

[Polymer elastic body]
In the sheet material of the present invention, the hydrophilic group-containing polymeric elastomer includes water-dispersible silicone resins, water-dispersible acrylic resins, water-dispersible urethane resins, and copolymers thereof. Among them, a water-dispersed polyurethane resin is preferably used in terms of texture.

As the water-dispersible polyurethane resin, a resin obtained by reacting a polymer polyol, an organic diisocyanate, and a chain extender is preferably used. In order to increase the stability of the aqueous dispersion of the water-dispersed polyurethane resin (hereinafter referred to as the water-dispersed polyurethane dispersion), it is preferable to use an active hydrogen component-containing compound having a hydrophilic group. A case of using a water-dispersed polyurethane resin as the elastic polymer will be described below.

(1) Reactive components of water-dispersed polyurethane resin First, each reactive component of the water-dispersed polyurethane resin will be described.

(1-1) Polymeric Polyol Examples of polymeric polyols that can be used in the sheet material of the present invention include polyether-based polyols, polyester-based polyols, and polycarbonate-based polyols.

Polyether-based polyols include polyols obtained by adding and polymerizing monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and cyclohexylene using a polyhydric alcohol or polyamine as an initiator, and Examples thereof include polyols obtained by ring-opening polymerization of the above monomers using a protonic acid, a Lewis acid, a cationic catalyst, or the like as a catalyst. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., and copolymer polyols combining them.

Polyester-based polyols include polyester polyols obtained by condensing various low-molecular-weight polyols with polybasic acids, polyols obtained by opening polymerization of lactones, and the like.

Examples of low molecular weight polyols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1.8- Linear alkylene glycols such as octanediol, 1,9-nonanediol and 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol and 2,4-diethyl-1,5-pentane Diols, branched alkylene glycols such as 2-methyl-1,8-octanediol, alicyclic diols such as 1,4-cyclohexanediol, and divalent aromatics such as 1,4-bis(β-hydroxyethoxy)benzene One or two or more selected from alcohols and the like can be mentioned. Adducts obtained by adding various alkylene oxides to bisphenol A can also be used as low-molecular-weight polyols.

Examples of polybasic acids include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro One or two or more selected from the group consisting of isophthalic acid and the like can be mentioned.

Examples of polycarbonate-based polyols include compounds obtained by reacting polyols with carbonate compounds such as dialkyl carbonates and diaryl carbonates.

As the polyol used as the raw material for producing the polycarbonate polyol, the polyol mentioned in the raw material for producing the polyester polyol can be used. Examples of dialkyl carbonate include dimethyl carbonate and diethyl carbonate, and examples of diaryl carbonate include diphenyl carbonate.

In the sheet material of the present invention, it is preferable that the elastic polymer contains polyetherdiol as a constituent component. In the present specification, "contained as a constituent" means contained as a monomer component or an oligomer component that constitutes the elastic polymer. Polyether diol has a low glass transition temperature due to the high degree of freedom of the ether bond, and also has a weak cohesive force, so that a polyurethane having excellent flexibility can be easily obtained.

In the sheet-like article of the present invention, the polymeric elastic body comprises a hydrophilic group-containing polymeric elastic body A containing polyether diol as a constituent component, and a hydrophilic group-containing hydrophilic group containing polycarbonate diol as a constituent component. It is preferably composed of a molecular elastic body B. A polymer elastomer A having hydrophilic groups, which contains polyether diol as a component with excellent flexibility, and a hydrophilic group, which contains polycarbonate diol, as a component with excellent durability against external stimuli such as light and heat. By including both of the polymeric elastic bodies B in the inside of the sheet-like material, it becomes easy to obtain a flexible and durable sheet-like material.

The number average molecular weight of the polymer polyol is preferably 500 or more and 5000 or less. By setting the number average molecular weight of the polymer polyol to 500 or more, more preferably 1500 or more, it is possible to easily prevent the texture from becoming hard. Further, by setting the number average molecular weight to 5,000 or less, more preferably 4,000 or less, the strength of the polyurethane as a binder can be easily maintained.

(1-2) Organic Diisocyanate The organic diisocyanate used in the present invention includes an aromatic diisocyanate having 6 to 20 carbon atoms (excluding carbon in the NCO group, hereinafter the same), and an aromatic diisocyanate having 2 to 18 carbon atoms. Aliphatic diisocyanates, alicyclic diisocyanates having 4 to 15 carbon atoms, araliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates (carbodiimide modified products, urethane modified products, uretdione modified products, etc.). ) and mixtures of two or more thereof.

Specific examples of the aromatic diisocyanate having 6 to 20 carbon atoms include 1,3- and/or 1,4-phenylene diisocyanate, 2,4- and/or 2,6-tolylene diisocyanate, 2,4 '- and/or 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated 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 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6 -diisocyanatomethylcaproate, bis(2-isocyanatoethyl)carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexaate.

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

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

Among these, preferred organic diisocyanates are alicyclic diisocyanates. A particularly preferred organic diisocyanate is dicyclohexylmethane-4,4'-diisocyanate.

(1-3) Chain Extender The chain extender used in the present invention includes water, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, and diethylene glycol. and neopentyl glycol”, alicyclic diols such as “1,4-bis(hydroxymethyl)cyclohexane”, aromatic diols such as “1,4-bis(hydroxyethyl)benzene”, “ethylenediamine Aliphatic diamines such as "isophoronediamine", alicyclic diamines such as "isophoronediamine", aromatic diamines such as "4,4-diaminodiphenylmethane", araliphatic diamines such as "xylenediamine", alkanols such as "ethanolamine" Amines, hydrazines, dihydrazides such as "adipic acid dihydrazide", and mixtures of two or more thereof.

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

(2) Additives for water-dispersed polyurethane resin In the present invention, it is important for the reason described later that an inorganic salt containing a monovalent cation and a thickener are contained in the aqueous dispersion containing the water-dispersed polyurethane. .

In addition, if necessary, colorants such as titanium oxide, ultraviolet absorbers (benzophenone, benzotriazole, etc.) and antioxidants [4,4-butylidene-bis(3-methyl-6-1-butylphenol) and other hinder organic phosphites such as triphenyl phosphite and trichloroethyl phosphite], inorganic fillers (such as calcium carbonate), and the like.

(3) Structure of water-dispersible polyurethane resin In the water-dispersible polyurethane used in the present invention, examples of the component that makes the polyurethane contain a hydrophilic group include a hydrophilic group-containing active hydrogen component. Examples of hydrophilic group-containing active hydrogen components include compounds containing nonionic groups and/or anionic groups and/or cationic groups and active hydrogen.

Compounds having a nonionic group and active hydrogen include compounds containing two or more active hydrogen components or two or more isocyanate groups and having a polyoxyethylene glycol group having a molecular weight of 250 to 9000 in the side chain, and triols such as trimethylolpropane and trimethylolbutane.

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

Compounds containing a cationic group and active hydrogen include tertiary amino group-containing compounds such as 3-dimethylaminopropanol, N-methyldiethanolamine, N-propyldiethanolamine, and derivatives thereof.

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

Hydrophilic group-containing active hydrogen components used in polyurethane molecules are 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and It is preferred to use these neutralized salts.

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

In the sheet material of the present invention, the hydrophilic group-containing polymeric elastomer has an N-acylurea bond and/or an isourea bond. That is, in the sheet material of the present invention, the elastic polymer has hydrophilic groups and N-acylurea bonds and/or isourea bonds.

When a water-dispersible polyurethane resin is used as the polymeric elastomer having a hydrophilic group, the N-acylurea bond and/or isourea bond are, for example, hydroxyl groups and/or carboxyl groups present as the hydrophilic group-containing active hydrogen component. It can be formed by reacting a group with a carbodiimide-based cross-linking agent. As a result, a three-dimensional crosslinked structure with N-acyl urea bonds and/or isourea bonds, which has excellent physical properties such as light resistance, heat resistance, and abrasion resistance, and flexibility, is imparted to the molecules of the elastic polymer having hydrophilic groups. In addition, physical properties such as abrasion resistance can be dramatically improved while maintaining the flexibility of the sheet material. The presence of the N-acylurea group or the isourea group in the elastic polymer is determined by mapping the cross section of the sheet-like material, for example, by time-of-flight secondary ion mass spectrometry (TOF-SIMS analysis). can be analyzed by

The number average molecular weight of the elastic polymer having a hydrophilic group used in the present invention is preferably 20,000 or more from the viewpoint of resin strength, and is preferably 500,000 or less from the viewpoint of viscosity stability and workability. preferable. The number average molecular weight is more preferably 30,000 or more and 150,000 or less.

The number average molecular weight of the elastic polymer having hydrophilic groups can be determined by gel permeation chromatography, and is measured under the following conditions, for example.
・Equipment: HLC-8220 manufactured by Tosoh Corporation
・Column: Tosoh TSKgel α-M
・Solvent: N,N-dimethylformamide (DMF)
・Temperature: 40℃
Proofreading: Polystyrene The elastic polymer having a hydrophilic group used in the present invention moderately holds the fibers in the sheet, and preferably has naps on at least one side of the sheet. It is a preferred embodiment that it exists inside the fibrous base material.

[Sheet]
The sheet material of the present invention has a length of 10 μm or more from the bonding portion with the ultrafine fibers in a 500 μm square range including 500 or more ultrafine fiber cross-sections in the cross section of the sheet material cut in the thickness direction. and the maximum width of the portion within 10 μm from the bonding portion with the ultrafine fiber is more than 0 μm and 5 μm or less, and the number of the elastic macromolecules is 20 or more. In the present specification, "polymer elasticity having a length of 10 μm or more from the bonding portion with the ultrafine fiber and a maximum width of 0 μm or less and 5 μm or less at the portion within 10 μm from the bonding portion with the ultrafine fiber "Body" is sometimes referred to as "thread-like polymeric elastic body".

The filamentous polymeric elastic material has a weak force to bind the ultrafine fibers, and thus contributes to the softening of the sheet-like material, that is, to the improvement of the texture. In addition, when the sheet-like material has a napped layer, the filamentous elastic polymer has a small domain size, so that the filamentous elastic polymer is excellent in raising the nap, thereby giving a glossy feeling.

The number of the thread-like polymeric elastic bodies is preferably 30 or more.

The filamentous elastic polymer is the cross section of the ultrafine fibers in five sheets obtained by observing the cross section cut in the thickness direction of the sheet material at a magnification of 500 using a scanning electron microscope (SEM VE-7800 manufactured by Keyence Corporation). The average number of filamentous polymeric elastomers existing in a 500 μm square area including 500 or more per sheet is calculated. Here, 500 or more ultrafine fibers in a cross section means that the number of ultrafine fibers whose cut cross section can be observed is 500 or more in the cross section of the sheet material.

When the elastic polymer is bonded to three or more ultrafine fibers at the same time, the length from the bonding portion of the elastic polymer to the ultrafine fibers to the branched portion is 10 μm or more, and When the maximum width of the portion within 10 μm exceeds 0 μm and is 5 μm or less, it is defined as a thread-like elastic polymer. Also, the maximum width here refers to the maximum width in the observed cross section ignoring the depth.

FIG. 2 shows an example of a method for defining the thread-like elastic polymer in the sheet-like material of the present invention. In FIG. 2, the elastic polymer 1 bonded to the ultrafine fibers 3 and 4 has a maximum width of 0.6 μm, and the length a, that is, from the bonding portion A with the ultrafine fibers to the bonding portion B with the ultrafine fibers is 14 μm. . Therefore, the elastic polymer 1 can be regarded as a thread-like elastic polymer. The length b of the elastic polymer 2 bonded to the microfibers 3, 4, and 5 has a maximum width of 0.6 μm, and the length b from the microfiber bonding portion to the branched portion is 14 μm, and the filamentous shape is formed. It can be regarded as an elastic polymer. Similarly, the portion of length c also has a maximum width of 0.6 μm and length c of 16 μm, and can be regarded as a thread-like polymeric elastic body. On the other hand, the portion of length d has a maximum width of 2 μm, and the length d from the ultrafine fiber bonded portion to the branched portion is 8 μm, which is less than 10 μm. Therefore, the elastic polymer at the portion of length d cannot be regarded as a thread-like elastic polymer. Two thread-like elastic polymer bodies are present from the elastic polymer body 2 .

Further, FIG. 3 shows another example of a method for defining the thread-like elastic polymer in the sheet-like material of the present invention. The elastic polymer in FIG. 3 shows another example of a branched elastic polymer. In the polymer elastic body 6 bonded to the ultrafine fibers 7, 8, and 9, the length e portion has a maximum width of 0.6 μm, and the length e from the ultrafine fiber bonding portion to the branched portion is 15 μm. It can be regarded as an elastic polymer. The portion of length f is 25 μm and can be regarded as a thread-like polymeric elastic body. On the other hand, the portion of length g has a maximum width of 0.6 μm, and the length g from the ultrafine fiber bonded portion to the branched portion is 6 μm, which is less than 10 μm. Therefore, it cannot be regarded as a thread-like polymeric elastic body. Moreover, the maximum width of the portion having the maximum width h is 10 μm or more, and cannot be regarded as a thread-like polymeric elastic body. Although the maximum widths i and j are 4 μm, the length k to the branched portion is 1 μm and less than 10 μm, so neither can be regarded as a thread-like elastic polymer. That is, the polymeric elastic body 6 includes two thread-like polymeric elastic bodies.

As a method for increasing the number of filamentous polymeric elastic bodies to 20 or more, for example, the fibrous base material is impregnated with an aqueous dispersion containing a monovalent cation-containing inorganic salt or the like, which will be described later, and then coagulation treatment and drying are performed. and a method of obtaining a sheet-like material.

In the present invention, it is preferable that the sheet has a napped layer, and the surface coverage of the ultrafine fibers in the napped layer is 60% or more and 100% or less. By setting the surface coverage to 60% or more, preferably 65% or more, it is possible to obtain a sheet-like material with a more elegant surface appearance and a glossy feel. As a principle for improving glossiness, it is presumed that by setting the surface coverage within the above range, the surface of the napped layer is easily smoothed, and a surface with high specular reflectance of light is easily obtained. In other words, if the fiber portion on the surface is dense, the reflectance of light increases and glossiness is produced.

The surface coverage rate is measured by SEM at an observation magnification of 30 to 70 times so that the presence of napped fibers can be seen on the napped surface, and using image analysis software, the ratio of the total area of the napped portion ^per total area of 4 mm The average value of the numerical values for the five SEM images was taken as the nap coverage. The ratio of the total area can be calculated by binarizing the photographed SEM image using the image analysis software "ImageJ" and setting the threshold value of 100 for the napped portion and the non-piped portion. In addition, in the calculation of the napped hair coverage, if a substance other than the napped hair is calculated as the napped hair and greatly affects the napped hair coverage ratio, the image is edited manually and the portion is calculated as the non-piped portion.

As an image analysis system, the image analysis software "ImageJ" is exemplified. It is not limited to "ImageJ". The image processing software “ImageJ ver. 1.8.0 — 112” is commonly used software developed by the National Institutes of Health. The image processing software "ImageJ" has a function of specifying a necessary area in the captured image and performing pixel analysis.

[Manufacturing method of sheet]
Next, the method for manufacturing the sheet-like material of the present invention will be described.

The method for producing the sheet-shaped material of the present invention is a method for producing the sheet-shaped material of the present invention, comprising a step of impregnating a fibrous base material with an aqueous dispersion, and coagulating with a coagulating solvent having a pH of 1 or more and 3 or less. A step of coagulating by an acid coagulation method in which the treatment is performed or a hot water coagulation method in which coagulation is performed in hot water at 80 ° C or higher and 100 ° C or lower, and a step of drying at 100 ° C or higher and 180 ° C or lower. The base material is made of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion comprises an elastic polymer having a hydrophilic group, a cross-linking agent, and a solid polymer elastic material having a hydrophilic group. It contains 10 parts by mass or more and 50 parts by mass or less of a monovalent cation-containing inorganic salt and a thickener per 100 parts by mass.

The method for producing a sheet of the present invention includes a step of impregnating a fibrous base material with an aqueous dispersion in order to impart an elastomeric polymer resin having a hydrophilic group to the fibrous base material. When a nonwoven fabric is used as the fibrous base material, either a nonwoven fabric made of composite fibers or a nonwoven fabric made into ultrafine fibers can be used.

From the viewpoint of the storage stability of the aqueous dispersion, the concentration of the elastomer having a hydrophilic group in the aqueous dispersion (the content of the elastomer having a hydrophilic group relative to the aqueous dispersion) Taking the mass of the entire liquid as 100% by mass, the content is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less.

In addition, the aqueous dispersion may contain a water-soluble organic solvent in an amount of 40% by mass or less in order to improve storage stability and film-forming properties. From this point of view, the content of the water-soluble organic solvent is preferably 1% by mass or less.

In the method for producing a sheet-like material of the present invention, 10 parts by mass or more and 50 parts by mass or less of a monovalent cation-containing inorganic material is added to the aqueous dispersion with respect to 100 parts by mass of the solid content of the elastic polymer having a hydrophilic group. Contains salt. By including the monovalent cation-containing inorganic salt, the aqueous dispersion can be imparted with heat-sensitive coagulability. In the present invention, the heat-sensitive coagulability refers to the property that when the water dispersion is heated and reaches a certain temperature (heat-sensitive coagulation temperature), the fluidity of the water dispersion is reduced and it solidifies.

In the method for producing a sheet-like material of the present invention, after the fibrous base material is impregnated with the aqueous dispersion, coagulation treatment and drying are performed. Since a polymer elastomer having hydrophilic groups tends to swell in an aqueous solution, coagulation is not completely completed after the coagulation treatment. Therefore, when the elastic polymer having a hydrophilic group does not have heat-sensitive coagulability, the elastic polymer, which has not completely coagulated into ultrafine fibers when the sheet is dried, covers the periphery of the fibers. The structure strongly constrains movement. This is because coagulation progresses in a state in which the elastic polymer is unevenly distributed around the fibers due to the occurrence of migration, which migrates to the sheet surface as the water evaporates, and as the water evaporates. These harden the texture of the sheet material.

The thermal solidification temperature of the aqueous dispersion is preferably 55° C. or higher and 80° C. or lower, more preferably 60° C. or higher and 70° C. or lower. By setting the heat-sensitive coagulation temperature to 55° C. or higher, the stability of the aqueous dispersion during storage is improved, and adhesion of the elastic polymer to the machine during operation can be easily suppressed. In addition, by setting the heat-sensitive coagulation temperature to 80° C. or lower, it is possible to suppress the phenomenon of migration of the elastic polymer to the surface layer of the fibrous base material. As the coagulation of the body progresses, a structure similar to that obtained by wet-coagulating a solvent-based elastic polymer, that is, a structure in which the elastic polymer does not strongly constrain the fibers, can be formed. It is possible to achieve a feeling of resilience, resilience.

The monovalent cation-containing inorganic salt is preferably sodium chloride and/or sodium sulfate. In conventional methods, inorganic salts having divalent cations such as magnesium sulfate and calcium chloride have been suitably used as heat-sensitive coagulants. Therefore, it is difficult to strictly control the heat-sensitive gelation temperature by adjusting the amount of the elastic polymer added. There were problems such as concerns about gelation during storage. On the other hand, the monovalent cation-containing inorganic salt with a small ionic valence has little effect on the stability of the aqueous dispersion, and by adjusting the amount added, the stability of the aqueous dispersion can be ensured. Solidification temperature can be strictly controlled.

In the method for producing a sheet of the present invention, the monovalent cation-containing inorganic salt is contained in an amount of 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the solid content of the elastic polymer having a hydrophilic group. By setting the content to 10 parts by mass or more, a large amount of ions present in the aqueous dispersion of the elastic polymer having a hydrophilic group uniformly act on the particles of the elastic polymer, resulting in a specific heat sensitivity. Solidification can be quickly completed at the solidification temperature. As a result, a more remarkable effect can be obtained in promoting coagulation of the elastic polymer while the fibrous base material contains a large amount of water, as described above. As a result, it is possible to form a structure very similar to that obtained by wet-coagulating a solvent-based elastic polymer, and to achieve good flexibility and resilience. On the other hand, by setting the content to 50 parts by mass or less, it is possible to leave an appropriate continuous film structure of the elastic polymer and suppress deterioration of physical properties. Also, the stability of the aqueous dispersion can be maintained.

In the method for producing a sheet-shaped article of the present invention, the aqueous dispersion contains a cross-linking agent. Physical properties such as abrasion resistance can be improved by introducing a three-dimensional network structure into the polymeric elastomer using a cross-linking agent. Furthermore, by using the monovalent cation-containing inorganic salt together, it becomes possible to soften the sheet-like material by controlling the bonding structure between the elastic polymer and the fiber, and at the same time achieve high physical properties of the sheet-like material.

The cross-linking agent is preferably a carbodiimide-based cross-linking agent because the elastic polymer obtained after the reaction has excellent light resistance, heat resistance and abrasion resistance, and also has good flexibility.

Furthermore, by using a thickener together with the water-dispersed polyurethane dispersion, the water-dispersed polyurethane dispersion impregnated into the fibrous base material does not diffuse in the liquid bath due to the viscosity of the liquid, and the polyurethane drop-off during the solidification process can be suppressed, and a solidification process with excellent productivity can be achieved.

Nonionic, anionic, cationic and amphoteric thickeners can be applied as the thickener contained in the aqueous dispersion. Among them, it is preferable that the thickener is a nonionic thickener because it hardly affects the stability of the aqueous dispersion.

The type of thickener can be selected from associative thickeners and water-soluble polymer thickeners.

A urethane-modified compound, an acrylic-modified compound, a copolymer compound thereof, or the like can be used as the associative thickener.

Examples of water-soluble polymeric thickeners include natural polymeric compounds, semi-synthetic polymeric compounds and synthetic polymeric compounds.

Natural polymer compounds include nonionic compounds such as tamarind gum, guar gum, roasted bean gum, tragacanth gum, starch, dextrin, gelatin, agarose, casein, and curdlan, as well as xanthan gum, carrageenan, gum arabic, pectin, collagen, and chondroitin. Anionic agents such as sodium sulfate, sodium hyaluronate, carboxymethyl starch and starch phosphate, and cationic agents such as cationic starch and chitosan can be used.

Semi-synthetic polymers include nonionic ones such as methylcellulose, ethylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, methylhydroxypropylcellulose, soluble starch and methylstarch, and anionic ones such as carboxymethylcellulose, carboxymethylstarch and alginate. and the compound of

Synthetic polymer compounds include nonionic compounds such as polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polymethylvinyl ether, polyethylene glycol, and polyisopropylacrylamide, and anions such as carboxyvinyl polymer, sodium polyacrylate, and sodium polystyrene sulfonate. and cationic compounds such as dimethylaminoethyl (meth)acrylate quaternary salt, dimethyldiallylammonium chloride, polyamidine, polyvinylimidazoline, and polyethyleneimine.

The viscosity of the aqueous dispersion containing the thickener is preferably 200 mPa·s to 100000 mPa·s. By setting the viscosity of the aqueous dispersion to 200 mPa s or more, it becomes easy to suppress the polyurethane from falling off in the hot water coagulation step, and by setting the viscosity to 100,000 mPa s or less, the aqueous dispersion becomes fibrous. It becomes easier to uniformly impregnate the base material.

In the method for producing a sheet-like material of the present invention, the coagulation after imparting the elastic polymer having a hydrophilic group is performed by an acid coagulation method in which a coagulation treatment is performed with a coagulation solvent having a pH of 1 or more and 3 or less, or a temperature of 80° C. or more and 100° C. or less. A hot water coagulation method is used in which coagulation is performed with hot water. Another coagulation method, for example, a dry heat coagulation method, is a technique in which a sheet impregnated with an elastic polymer having a hydrophilic group is heat-treated using a hot air dryer or the like. Solidification of the elastic polymer progresses. As a result, the elastic macromolecules tend to agglomerate with each other, increasing the domain size. On the other hand, in the present invention, since the coagulation treatment is performed in a liquid bath, the coagulation progresses while the polymeric elastomer diffuses inside the sheet. Therefore, the domain size of the elastic polymer becomes smaller, and the sheet tends to have a glossy feeling.

In the method for producing a sheet material of the present invention, the coagulation solvent used in the acid coagulation method has a pH of 1 or more and 3 or less. The pH is preferably pH 1.5 or more and 2.5 or less. By setting the pH to 3 or less, the coagulation of the elastic polymer is facilitated. Further, by setting the pH to 1 or higher, deterioration of the elastic polymer can be easily prevented.

The liquid temperature of the coagulating solvent in the acid coagulation method is preferably 20° C. or higher and 95° C. or lower.

In addition, the temperature of the solidifying solvent in the hydrothermal coagulation method is preferably 80° C. or higher and 100° C. or lower, more preferably 85° C. or higher and 95° C. or lower, thereby achieving a porous structure.

Furthermore, in the method for producing a sheet-like material of the present invention, the aqueous dispersion contains a cross-linking agent, and after the coagulation treatment, it is preferably dried at a temperature of 100° C. or higher and 180° C. or lower, more preferably 120° C. or higher and 160° C. or lower. The treatment can sufficiently promote the cross-linking reaction and improve the physical properties. Further, by setting the heating temperature to 180° C. or less, thermal deterioration of the elastic polymer can be suppressed.

In addition, the method for producing a sheet-like material of the present invention may optionally further include a step of removing PVA from the fibrous base material to which the elastic polymer having hydrophilic groups has been applied. By removing the PVA from the fibrous base material to which the elastic polymer having hydrophilic groups has been imparted, it becomes easier to obtain a flexible sheet-like material. Although the method for removing PVA is not particularly limited, for example, the sheet is immersed in hot water of 60° C. or higher and 100° C. or lower, and if necessary, it is dissolved and removed by squeezing with a mangle or the like. be.

In the present invention, at least one surface of the sheet-like material may be raised to form naps on the surface. The method for forming naps is not particularly limited, and various methods commonly used in the art, such as buffing with sandpaper or the like, can be used. If the nap length is too short, it is difficult to obtain an elegant appearance, and if it is too long, pilling tends to occur easily.

In one aspect of the present invention, the sheet can be dyed. As the dyeing method, various methods commonly used in the art can be adopted. A method using a jet dyeing machine is preferable because the sheet-like material can be softened by applying a kneading effect at the same time as the sheet-like material is dyed.

The dyeing temperature is preferably 80° C. or higher and 150° C. or lower, although it depends on the type of fiber. By setting the dyeing temperature to 80° C. or higher, more preferably 110° C. or higher, the fibers can be efficiently dyed. On the other hand, by setting the dyeing temperature to 150° C. or lower, more preferably 130° C. or lower, deterioration of the elastic polymer can be prevented.

The dye used in the present invention may be selected according to the type of fiber constituting the fibrous base material, and is not particularly limited. For example, disperse dyes can be used for polyester fibers, and polyamide fibers Acid dyes and metallized dyes can be used, and combinations thereof can be used. In the case of dyeing with a disperse dye, reduction cleaning may be performed after dyeing.

It is also a preferred embodiment to use a dyeing assistant during dyeing. By using a dyeing aid, the uniformity and reproducibility of dyeing can be improved. In addition, in the same bath as dyeing or after dyeing, for example, a finishing treatment using a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, a light fastness agent, an antibacterial agent, or the like can be applied.

The sheet-like material of the present invention can be used as interior materials, shirts, jackets, etc., having a very elegant appearance as furniture, chairs and wall materials, and covering materials such as seats, ceilings and interiors in vehicle interiors such as automobiles, trains and aircraft. Casual shoes, sports shoes, men's and women's shoe uppers, trims, etc., bags, belts, wallets, etc., and clothing materials used for some of them, wiping cloths, polishing cloths, CD curtains, etc. It can be suitably used as a material.

EXAMPLES Next, the sheet-like article and the method for producing the same of the present invention will be described in more detail with reference to examples, but the present invention is not limited only to these examples.

[Evaluation method]
(1) Average single fiber fineness of sheet:
A cross-section perpendicular to the thickness direction of the sheet containing fibers is observed at a magnification of 3000 using a scanning electron microscope (SEM VE-7800 manufactured by Keyence Corporation), and randomly extracted within a field of view of 30 μm × 30 μm. The 50 single fiber diameters were measured in μm to one decimal place. However, this was done at three locations, the diameters of a total of 150 single fibers were measured, and the average value was calculated to one decimal place. If fibers with a fiber diameter of more than 50 μm are mixed, the fibers are considered not to be ultrafine fibers and are excluded from measurement of the average fiber diameter. When the ultrafine fibers had an irregular cross section, the cross-sectional area of the single fiber was first measured as described above, and the diameter of the single fiber was obtained by calculating the diameter when the cross section was assumed to be circular. An average value was calculated using this population as the average single fiber fineness.

(2) Flexibility of sheet material:
JIS L 1096: Based on 8.21 "Bending resistance" of JIS L 1096: 2010 "Fabric test method for woven and knitted fabrics", A method (45 ° cantilever method) described in 8.21.1 In the vertical and horizontal directions Five test pieces of 2 × 35 cm each are prepared, placed on a horizontal table having a slope at an angle of 45 °, the test piece is slid, and the scale is read when the center point of one end of the test piece contacts the slope, An average value of 5 sheets was obtained.

(3) Solidification temperature of aqueous dispersion of elastic polymer having hydrophilic group Test 20 g of the aqueous dispersion containing the elastic polymer having hydrophilic group prepared in each example and comparative example with an inner diameter of 12 mm After inserting the thermometer so that the tip is below the liquid surface, the test tube is sealed and placed in a hot water bath at a temperature of 95°C. It was immersed so that the liquid level of the hot water bath was lower than the liquid level of the hot water bath. While confirming the temperature rise in the test tube with a thermometer, the test tube is pulled up for a period of 5 seconds or less each time, and the presence or absence of fluidity of the liquid surface of the aqueous dispersion of the polymeric elastomer having a hydrophilic group. The solidification temperature was defined as the temperature at which the liquid surface of the aqueous dispersion of the elastic polymer having a hydrophilic group lost its fluidity. This measurement was performed three times for each type of aqueous dispersion of the elastic polymer having a hydrophilic group, and the average value was calculated.

(4) Identification of binding species in the elastic polymer The binding species of the elastic polymer separated from the sheet material was identified by infrared spectroscopic analysis using FT/IR 4000 series manufactured by JASCO Corporation. identified.

(5) Appearance quality of sheet:
The surface quality of the obtained sheet-like material was evaluated by a panel of 10 people and evaluated according to the following criteria. The surface quality is evaluated by placing a sheet 12 on an inspection table 11 parallel to the floor surface 10 as shown in FIG. Judgment was made by visually confirming the sheet-like material 14 at an angle of 45° from the plane of the inspection table so that the distance was 50 cm. In addition, a fluorescent lamp 15 of 32 W was installed on the examination table 150 cm above the upper surface of the examination table in the vertical direction. The surface quality evaluation was performed by placing the sheet 12 directly below the fluorescent lamp 15, that is, at a position where a perpendicular line 16 can be drawn from the sheet to the fluorescent lamp. Appearance grades 4 to 5 were judged to be good.
Grade 5: The fibers are well dispersed and the appearance with glossiness is good. When the sheet has a napped layer, there is a uniform nap of fibers.
Grade 4: A rating between grades 5 and 3.
Grade 3: Although the fiber dispersion state is somewhat poor in some areas, the appearance is reasonably good, but there is no glossiness. When the sheet-like material has a napped layer, there is napped fibers, though not uniformly.
Grade 2: An evaluation between Grade 3 and Grade 1.
Grade 1: Overall, the state of dispersion of fibers is very poor, and the appearance is poor. When the sheet-like material has a napped layer, there are many portions where there is a lot of unevenness and where naps do not appear.

[Reference Example 1: Preparation of aqueous dispersion Wa of elastic polymer a having hydrophilic groups]
Polytetramethylene ether glycol having a number average molecular weight (Mn) of 2,000 as a polyol (described as PTMG in the table), MDI as an isocyanate, and 2,2-dimethylolpropionic acid as a component containing a hydrophilic group, A prepolymer was made in toluene solvent. Ethylene glycol and ethylenediamine as chain extenders, and polyoxyethylene nonylphenyl ether and water as external emulsifiers were added and stirred. Toluene was removed under reduced pressure to obtain an aqueous dispersion Wa of an elastic polymer a having a hydrophilic group. In addition, the polymeric elastic body a is a polymeric elastic body corresponding to the polymeric elastic body A.

[Reference Example 2: Preparation of aqueous dispersion Wb of elastic polymer b having hydrophilic group]
Polyhexamethylene carbonate with an Mn of 2,000 (described as PHC in the table) as a polyol, hydrogenated MDI as an isocyanate, and a diol compound having polyethylene glycol in its side chain and a 2,2-diol compound as a component containing a hydrophilic group. A prepolymer was made in acetone solvent using methylolpropionic acid. Ethylene glycol, ethylenediamine and water were added as chain extenders and stirred. Acetone was removed under reduced pressure to obtain an aqueous dispersion Wb of an elastic polymer b having a hydrophilic group. Note that the elastic polymer b is a polymer elastic body corresponding to the elastic polymer B. FIG.

[Example 1]
(non-woven fabric)
Polyethylene terephthalate obtained by copolymerizing 8 mol% sodium 5-sulfoisophthalate was used as the sea component, and polyethylene terephthalate was used as the island component. A sea-island composite fiber having 16 islands/1 filament and an average fiber diameter of 20 μm was obtained. The islands-in-the-sea composite fiber thus obtained was cut into a fiber length of 51 mm, stapled, passed through a card and a cross wrapper to form a fiber web, and needle-punched to form a non-woven fabric. The nonwoven fabric thus obtained was immersed in hot water at a temperature of 97° C. for 2 minutes to shrink, and dried at a temperature of 100° C. for 5 minutes.

(fiber reinforcement)
The above nonwoven fabric for fibrous base materials is impregnated with a 10% by mass aqueous solution of PVA (NM-14 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a degree of saponification of 99% and a degree of polymerization of 1400, and dried by heating at a temperature of 140 ° C. for 10 minutes. As a result, a PVA-imparted sheet having a PVA adhesion amount of 30% by mass relative to the fiber mass of the nonwoven fabric for fibrous base material was obtained.

(ultrafine fibers)
The resulting PVA-imparted sheet was immersed in an aqueous sodium hydroxide solution having a concentration of 8 g/L heated to a temperature of 95° C. for 30 minutes to obtain a sheet made of ultrafine fibers from which the sea component of the sea-island composite fiber was removed ( A PVA-imparted ultrafine fiber nonwoven fabric) was obtained.

(Applying elastic polymer resin)
A nonionic thickener (guar gum) [Taiyo Kagaku Co., Ltd. "Neosoft G"] 1% by mass of the active ingredient of the polyurethane solid content, 30% by mass of sodium sulfate (described as "Na ₂ SO ₄ " in Table 1) as a heat-sensitive coagulant, and a carbodiimide-based 3% by mass of a cross-linking agent was added and water was added to adjust the solid content to 17% by mass, thereby obtaining an aqueous dispersion containing the elastic polymer a having a hydrophilic group. The thermal solidification temperature was 65°C. The resulting PVA-imparted ultrafine fiber nonwoven fabric is immersed in the aqueous dispersion, followed by an acid coagulation treatment, i.e., treatment in a pH 2 solution for 10 minutes, followed by hot air drying at a drying temperature of 120°C for 30 minutes. A 2.0 mm thick elastic polymer resin-imparted sheet to which 45% by mass of polyurethane was imparted was obtained.

(Removal of reinforcing resin)
The resulting elastic polymer resin-applied sheet was immersed in water heated to 95° C. for 10 minutes to remove the applied PVA to obtain a sheet-like product.

(Half-cut and brushed)
The obtained elastic polymer resin-imparted sheet after removal of PVA was cut in half perpendicularly to the thickness direction, and the opposite side of the cut surface was ground with endless sandpaper of No. 240 sandpaper count to a thickness of 0.7 mm. to obtain a sheet-like material having a nap of .

(dyeing and finishing)
The obtained sheet-like material having nap was dyed with a black dye at a temperature of 120° C. using a jet dyeing machine. Then, it was dried in a drier to obtain a sheet-like material having ultrafine fibers with an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of thread-like elastic polymer was 49, and the surface coverage was 72%.

[Example 2]
(non-woven fabric)
It was carried out in the same manner as in Example 1.

(ultrafine fibers)
It was carried out in the same manner as in Example 1.

(Applying elastic polymer resin)
An active ingredient of a nonionic thickener (guar gum) was added to a water-dispersible polyurethane dispersion Wa prepared to have a polyurethane solid content concentration of 20% with respect to a solid content of 100% by mass of the elastic polymer a having hydrophilic groups. is added to 1% by mass of the polyurethane solid content, 30% by mass of sodium sulfate is added as a heat-sensitive coagulant, 3% by mass of a carbodiimide-based cross-linking agent is added, and the whole is adjusted to a solid content of 17% by mass with water. An aqueous dispersion containing the molecular elastic body a was obtained. The thermal solidification temperature was 65°C. The resulting PVA-imparted ultrafine fiber nonwoven fabric was immersed in the aqueous dispersion, 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 120°C for 30 minutes. A 2.0 mm-thick elastic polymer resin-imparted sheet to which 45% by mass was imparted was obtained.

The process from cutting in half to finishing was carried out in the same manner as in Example 1 to obtain a sheet-like material having ultrafine fibers with an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of thread-like elastic polymer was 38, and the surface coverage was 69%.

[Example 3]
In Example 1 (application of elastic polymer resin), the aqueous dispersion containing the elastic polymer having a hydrophilic group was changed (specifically, the aqueous dispersion of the elastic polymer b having a hydrophilic group A sheet-like product having an average single fiber fineness of 4.4 μm was obtained in the same manner as in Example 1, except that the dispersion liquid Wb was changed. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of thread-like elastic polymer was 44, and the surface coverage was 66%.

[Example 4]
In Example 2 (application of elastic polymer resin), the aqueous dispersion containing the elastic polymer having a hydrophilic group was changed (specifically, the aqueous dispersion of the elastic polymer b having a hydrophilic group In the same manner as in Example 2 except that the dispersion was changed to the dispersion Wb), a sheet-like material having an average single fiber fineness of ultrafine fibers of 4.4 μm was obtained. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of thread-like elastic polymer was 40, and the surface coverage was 67%.

[Example 5]
In Example 1 (application of elastic polymer resin), sodium chloride (Table 1 25% by mass of NaCl) was added and the heat-sensitive coagulation temperature was adjusted to 60° C., in the same manner as in Example 1 to prepare a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers. Obtained. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of filamentous elastic polymers was 46, and the surface coverage was 70. [Example 6]
In Example 1 (application of elastic polymer resin), 45 mass of sodium sulfate as a heat-sensitive gelling agent was added to 100 mass% of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. %, and the heat-sensitive coagulation temperature was adjusted to 60° C., in the same manner as in Example 1 to obtain a sheet material having an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of filamentous elastic polymers was 51, and the surface coverage was 68%.

[Example 7]
In Example 1 (application of elastic polymer resin), 18 mass of sodium sulfate as a heat-sensitive gelling agent was added to 100 mass% of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. %, and the heat-sensitive coagulation temperature was adjusted to 70° C., in the same manner as in Example 1 to obtain a sheet-like material having an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a structure in which the fibers and the elastic polymer were partially adhered to each other, and the length of the fibers in the surface layer was uniform, and it had a glossy feel, as in FIG. 1 . In addition, N-acyl urea bonds and isourea bonds were present in the elastic polymer, the number of thread-like elastic polymer was 33, and the surface coverage was 66%.

[Comparative Example 1]
30% by mass of sodium sulfate as a heat-sensitive coagulant and 3% by mass of a carbodiimide-based cross-linking agent are added to 100% by mass of the solid content of the elastic polymer a having hydrophilic groups, and the solid content is reduced to 17% by mass with water. % to obtain an aqueous dispersion containing the elastic polymer a having a hydrophilic group. The thermal solidification temperature was 65°C. The resulting PVA-added ultrafine fiber nonwoven fabric was immersed in the aqueous dispersion and then dried with hot air at 120°C for 30 minutes to impart 45% by mass of elastic polymer A to the weight of the fibers. , to obtain a polymer elastic resin-imparted sheet having a thickness of 1.9 mm. The obtained sheet-like material had a soft texture, but the appearance quality was grade 3. The elastic polymer had N-acyl urea bonds and isourea bonds, and the surface coverage was 67%.

[Comparative Example 2]
In Example 1 (application of elastic polymer resin), the procedure of Example 1 was repeated except that magnesium sulfate was used as the heat-sensitive coagulant. The dispersion liquid gelled during processing, and it was not possible to obtain a polymer elastic resin-applied sheet.

[Comparative Example 3]
In Example 1 (application of elastic polymer resin), 1.0% of magnesium sulfate as a heat-sensitive gelling agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. A sheet having an average single fiber fineness of 4.4 μm was obtained in the same manner as in Example 1, except that 2% by mass was added and the heat-sensitive coagulation temperature was adjusted to 60°C. The obtained sheet-like material had a soft texture, but uneven impregnation occurred, and the appearance quality was grade 3. Further, it was confirmed that the elastic polymer had N-acylurea bonds and isourea bonds, and the surface coverage was 63%, but the number of filamentous elastic polymers was 17.

[Comparative Example 4]
In Example 1 (application of elastic polymer resin), 1.0% of sodium sulfate as a heat-sensitive gelling agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. A sheet-like material having an average single fiber fineness of 4.4 μm was obtained in the same manner as in Example 1, except that 2% by mass was added and the heat-sensitive coagulation temperature was adjusted to 95°C. The obtained sheet material had a hard texture and an appearance quality of grade 2. Further, it was confirmed that the elastic polymer had N-acyl urea bonds and isourea bonds, the number of thread-like elastic polymers was 11, and the surface coverage was 55%.

[Comparative Example 5]
In Example 1 (application of elastic polymer resin), 60 mass of sodium sulfate as a heat-sensitive gelling agent was added to 100 mass% of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. %, and the heat-sensitive coagulation temperature was adjusted to 60° C., in the same manner as in Example 1 to obtain a sheet material having an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a soft texture, but the appearance quality was grade 3. Further, it was confirmed that the elastic polymer had N-acyl urea bonds and isourea bonds, and the surface coverage was 69%, but the number of filamentous elastic polymers was 14.

[Comparative Example 6]
Except that in Example 1 (application of elastic polymer resin), no cross-linking agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. A sheet material having an average single fiber fineness of 4.4 μm was obtained in the same manner as in Example 1. The obtained sheet-like material had a soft texture, but the appearance quality was second grade. It was also confirmed that the elastic polymer had N-acyl urea bonds and isourea bonds, the number of thread-like elastic polymers was 26, and the surface coverage was 58%.

[Comparative Example 7]
Except that in Example 1 (application of elastic polymer resin), no thickening agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. was carried out in the same manner as in Example 1 to obtain a sheet-like material having ultrafine fibers with an average single fiber fineness of 4.4 μm. The obtained sheet-like material had a soft texture, but the appearance quality was grade 3. Further, it was confirmed that the elastic polymer had N-acyl urea bonds and isourea bonds, the number of thread-like elastic polymers was 8, and the surface coverage was 58%.

[Comparative Example 8]
In Example 1 (application of elastic polymer resin), 3% by mass of an oxazoline cross-linking agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. Except for this, in the same manner as in Example 1, a sheet-like material having an average single fiber fineness of ultrafine fibers of 4.4 μm was obtained. The obtained sheet-like material had a soft texture, but the appearance quality was grade 3. In addition, the number of thread-like elastic polymer bodies was 39, and the surface coverage was 63%.

[Comparative Example 9]
Except that in Example 1 (application of elastic polymer resin), no heat-sensitive coagulant was added to 100% by mass of the solid content of the aqueous dispersion Wa of the elastic polymer a having a hydrophilic group. was carried out in the same manner as in Example 1 to obtain a sheet-like material having ultrafine fibers with an average single fiber fineness of 4.4 μm. The obtained sheet material had a hard texture and an appearance quality of grade 2. It was also confirmed that the elastic polymer had N-acyl urea bonds and isourea bonds, the number of thread-like elastic polymers was 10, and the surface coverage was 54%.

The results of Examples 1 to 7 and Comparative Examples 1 to 9 are summarized in Tables 1 and 2.

The sheet-like material of the present invention can be used for furniture, chairs and wall coverings, seats in vehicle interiors such as automobiles, trains and aircraft, surface materials for ceilings and interiors, interior materials having a very elegant appearance, and clothing and industrial materials. It can be suitably used as a material or the like.

1: elastic polymer 2: elastic polymer 3: ultrafine fiber 4: ultrafine fiber 5: ultrafine fiber 6: polymer elastic body 7: ultrafine fiber 8: ultrafine fiber 9: ultrafine fiber 10: floor surface 11: examination table 12: Sheet 13: Line connecting the position to be visually confirmed and the sheet 14: Position to be visually confirmed 15: Fluorescent lamp 16: Vertical line from the sheet to the fluorescent lamp

Claims (6)

A sheet-like material containing a fibrous base material and a polymeric elastic body, wherein the fibrous base material is made of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the polymeric elastic body comprises: Adhesion to ultrafine fibers in a 500 μm square range containing 500 or more ultrafine fiber cross-sections in a cross section obtained by cutting the sheet material in the thickness direction, and having a hydrophilic group and an N-acylurea bond and/or an isourea bond. A sheet-like material having a length of 10 μm or more from the portion and a maximum width of 20 or more elastic macromolecules having a maximum width of more than 0 μm and 5 μm or less at a portion within 10 μm from the portion bonded to the ultrafine fiber. . 2. The sheet-like material according to claim 1, wherein the number of said polymeric elastic bodies is 30 or more. 3. The sheet material according to claim 1, which has a napped layer, and the surface coverage of the ultrafine fibers in said napped layer is 60% or more and 90% or less. A method for producing a sheet-like material according to any one of claims 1 to 3, wherein the step of impregnating the fibrous base material with the aqueous dispersion, and performing a coagulation treatment with a coagulation solvent having a pH of 1 or more and 3 or less. A step of performing coagulation treatment by an acid coagulation method or a hot water coagulation method in which coagulation treatment is performed in hot water at 80 ° C. or higher and 100 ° C. or lower, and a step of drying at 100 ° C. or higher and 180 ° C. or lower. It consists of ultrafine fibers with an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion comprises an elastic polymer having a hydrophilic group, a cross-linking agent, and a solid content of the elastic polymer having a hydrophilic group. A method for producing a sheet material, comprising 10 parts by mass or more and 50 parts by mass or less of a monovalent cation-containing inorganic salt and a thickening agent. 5. The method for producing a sheet material according to claim 4, wherein the cross-linking agent is a carbodiimide-based cross-linking agent. 6. The method for producing a sheet material according to claim 4, wherein said thickener is a nonionic thickener.

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