JP2021021172A - Sheet-like material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like material having good surface quality, glossiness and texture, and a method for producing the same. A sheet-like material containing a fibrous base material and a polymer 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 polymer. The elastic body has a hydrophilic group and an N-acylurea bond and / or an isourea bond, and is ultrafine in a range of 500 μm square including 500 or more cross-sectional portions of ultrafine fibers in a cross section obtained by cutting a sheet-like material in the thickness direction. The number of polymer elastic bodies having a length of 10 μm or more from the bonded portion with fibers and a maximum width of 10 μm or less from the bonded portion with ultrafine fibers exceeding 0 μm and 5 μm or less is 20 or more. A sheet-like object. [Selection diagram] None

Description

The present invention relates to a sheet-like material and a method for producing the same, and more preferably, a sheet-like material having a napped layer and a method for producing the same.

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

In producing such a sheet, 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 of polyurethane. A combination of steps of wet coagulation of polyurethane is generally adopted. In this case, as the organic solvent which is the solvent of polyurethane, a water-miscible organic solvent such as N, N-dimethylformamide (hereinafter, also referred to as “DMF”) is used. However, since organic solvents are generally highly harmful to the human body and the environment, there is a strong demand for a method that does not use organic solvents in the production of sheet-like products.

As a specific solution, a method of using a water-dispersed polyurethane in which a polyurethane resin is dispersed in water is being studied instead of the conventional organic solvent-based polyurethane. So far, in order to obtain a sheet-like material having a soft texture by using water-dispersible polyurethane, for example, a water-dispersible polyurethane liquid containing a foaming agent has been applied to a fibrous base material such as a sheet made of a cloth such as a non-woven fabric. A method has been proposed in which a gas is generated in the polyurethane by applying and heating to make the structure of the polyurethane in the fibrous substrate a porous structure (see Patent Document 1).

In addition, the size of the polyurethane resin is reduced by impregnating the fibrous base material in a solution containing water-dispersible polyurethane and a thickener and immersing it in hot water, and the gripping force of the confounded portion of the fibers by the water-dispersible polyurethane is increased. A method for reducing the amount has been proposed (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2011-214210 International Publication No. 2015/129602

However, a sheet-like material obtained by impregnating a fibrous base material with an aqueous dispersion type polyurethane dispersion liquid in which water-dispersible polyurethane is dispersed in a liquid and solidifying the polyurethane has a problem that the texture tends to be hard.

One of the main reasons is the difference between the two coagulation methods. That is, the coagulation method of the organic solvent-based polyurethane liquid is a so-called wet coagulation method in which polyurethane molecules dissolved in an organic solvent are solvent-substituted with water to coagulate, and a porous film having a low density when viewed as a polyurethane film. Is formed. Therefore, even when polyurethane is impregnated in the fibrous base material and solidified, the adhesive area between the fiber and polyurethane is reduced, resulting in a soft sheet-like material.

On the other hand, the mainstream of water-dispersed polyurethane is a so-called moist heat coagulation method in which the hydrated state of the water-dispersed polyurethane dispersion is disrupted by heating and the polyurethane emulsions are coagulated to coagulate. The polyurethane film structure to be obtained is a dense non-porous film. Therefore, the fibrous base material and the polyurethane are closely adhered to each other, and the entangled portion of the fibers is strongly gripped, so that the texture becomes hard.

In the method disclosed in Patent Document 1, by making the water-dispersible polyurethane porous, the adhesive area between the fiber and the polyurethane is reduced, the gripping force at the entanglement point of the fiber is weakened, and the tactile sensation is flexible. It is possible to obtain a sheet-like material having a texture, but it tends to be less flexible as compared with the case where an organic solvent-based polyurethane is added.

On the other hand, in the method disclosed in Patent Document 2, the adhesive area between the fiber and the polyurethane is reduced by making the water-dispersible polyurethane porous, the gripping force at the entangled point of the fiber is weakened, and the tactile sensation is flexible. It is possible to obtain a sheet-like material having a good texture, but since a divalent cation-containing inorganic salt is used as a heat-sensitive coagulation adjuster, the occurrence of impregnation unevenness due to gelation of the impregnating solution is a problem.

Therefore, 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 view of the background of the above-mentioned prior art.

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

Further, the method for producing a sheet-like substance of the present invention is a method for producing a sheet-like substance of the present invention, in which a fibrous substrate is impregnated with an aqueous dispersion, and a coagulation solvent having a pH of 1 or more and 3 or less is used. A step of coagulating by an acid coagulation method or a hot water coagulation method of coagulating in hot water of 80 ° C. or higher and 100 ° C. or lower, and a step of drying at 100 ° C. or higher and 180 ° C. or lower are included. The fibrous base material is composed of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion is a polymer elastic body having a hydrophilic group, a cross-linking agent, and a polymer elastic having the hydrophilic group. It contains a monovalent cation-containing inorganic salt of 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of body solid content, and a thickener.

According to a preferred embodiment of the sheet-like material of the present invention, the number of the polymer elastic bodies is 30 or more.

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

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

According to the present invention, a sheet-like material having an elegant surface quality, a glossy feeling and a good texture can be obtained.

This is an example of a cross-sectional micrograph of the bonded portion between the polymer elastic body and the fiber in the sheet-like material of the present invention. It is a conceptual diagram which shows an example of the definition method of the thread-like polymer elastic body in the sheet-like material of this invention. It is a conceptual diagram which shows another example of the method of defining a thread-like polymer elastic body in the sheet-like material of this invention. It is a conceptual perspective view which illustrates the evaluation method of the surface quality of the sheet-like material which concerns on this invention.

The sheet-like material of the present invention is a sheet-like material containing a fibrous base material and a polymer elastic body, and the fibrous base material is composed of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less. The polymer elastic body has a hydrophilic group and an N-acylurea bond and / or an isourea bond, and is 500 μm square including 500 or more cross-sectional portions of ultrafine fibers in a cross section obtained by cutting a sheet-like material in the thickness direction. In the range, the number of polymer elastic bodies whose length from the portion bonded to the ultrafine fibers is 10 μm or more and the maximum width of the portion within 10 μm from the portion bonded to the ultrafine fibers exceeds 0 μm and is 5 μm or less. There are 20 or more. This component will be described in detail below, but the present invention is not limited to the scope described below as long as the gist thereof is not exceeded.

[Ultrafine fiber]
As the ultrafine fibers used in the present invention, polyester resins obtained from dicarboxylic acid and / or an ester-forming derivative thereof and a diol, that is, resins such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate can be used. it can.

Examples of the dicarboxylic acid and / or its ester-forming derivative used in the polyester resin include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and its ester-forming derivative. Can be mentioned. The ester-forming derivative referred to in the present invention is a lower alkyl ester of a dicarboxylic acid, an acid anhydride, an acyl chloride or the like. Specifically, methyl ester, ethyl ester, hydroxy ethyl ester and the like are preferably used. A more preferred embodiment of the dicarboxylic acid and / or ester-forming derivative thereof used in the present invention is terephthalic acid and / or a dimethyl ester thereof.

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

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

As the cross-sectional shape of the ultrafine fiber, a round cross section may be used, but polygonal shapes such as ellipse, flat and triangular, and irregular cross sections such as fan and cross can be adopted.

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, more preferably 5 μm or less, the sheet-like material can be made more flexible. Further, 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 material having excellent color development after dyeing can be obtained. .. Further, when the sheet-like material has naps, it is possible to improve the ease of dispersing and the ease of handling of the ultrafine fibers existing in the bundle shape when the nap treatment by buffing is performed.

The average single fiber fineness referred to in the present invention is measured by the following method. That is,
(1) The cross section of the sheet-like material cut in the thickness direction is observed with a scanning electron microscope (SEM).
(2) The fiber diameters of any 50 ultrafine fibers in the observation surface are measured in three directions in each ultrafine fiber cross section. However, when ultrafine fibers having a modified cross section are used, the cross-sectional area of the single fiber is first measured, and the diameter of the circle having the cross-sectional area is calculated by the following formula. The diameter obtained from this is taken as the single fiber diameter of the single fiber.
-Single fiber diameter (μm) = (4 x (single fiber cross-sectional area (μm ² )) / π) ^1/2
(3) Calculate the arithmetic mean value (μm) of the total of 150 points obtained, and round off to the second decimal place.

As a means for obtaining the ultrafine fibers used in the present invention, direct spinning or ultrafine fiber phenotypic fibers can be used. Above all, it is preferable to use ultrafine fiber-expressing fibers. The ultrafine fiber expression type fiber is a sea-island type in which two components of thermoplastic resin having different solubility in a solvent 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. Adopting a peelable composite fiber or a multi-layer composite fiber in which composite fibers or two-component thermoplastic resins are alternately arranged radially or in layers in a fiber cross section, and each component is separated and divided into ultrafine fibers. However, the sea-island type composite fiber is preferably used because it is easy to make the surface quality of the sheet-like material uniform.

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

The fiber ultrafine treatment (desealing treatment) of the sea-island type composite fiber can be performed by immersing the sea-island type composite fiber in a solvent and squeezing the liquid. As the solvent for dissolving the sea component, an organic solvent such as toluene or trichlorethylene, an alkaline aqueous solution such as sodium hydroxide, or hot water can be used.

For the fiber ultrafine processing, an apparatus such as a continuous dyeing machine, a vibro washer type dewatering machine, a liquid flow dyeing machine, a Wins dyeing machine and a jigger dyeing machine can be used.

The dissolution and removal of the sea component can be performed at any timing before and after the application of the polymer elastic body. If the desealing treatment is performed before the polymer elastic body is applied, the structure is such that the polymer elastic body is in direct contact with the ultrafine fibers, and the ultrafine fibers can be strongly gripped, so that the abrasion resistance of the sheet-like material becomes better. On the other hand, if the sea-removing treatment is performed after the polymer elastic body is applied, voids due to the de-sea components are generated between the polymer elastic body and the ultrafine fibers. The texture of the sheet-like material becomes more flexible without gripping.

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. When the mass ratio of the sea component is 10% by mass or more, the island component is likely to be sufficiently refined. Further, when the mass ratio of the sea component is 80 mass or less, the ratio of the eluted component is small, so that the productivity is improved. 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 an ultrafine fiber-expressing fiber represented by a sea-island type composite fiber is drawn, the undrawn yarn is once wound and then separately drawn, or the undrawn yarn is taken up and continuously drawn as it is. Any method can be adopted, such as. Stretching can be appropriately performed by a method of stretching in 1 to 3 steps by moist heat, dry heat, or both. Next, the stretched sea-island type composite fiber is preferably subjected to a crimping process and cut to a predetermined length to obtain a non-woven raw cotton. Ordinary methods can be used for crimping and cutting.

It is preferable that the composite fiber such as the sea-island type composite fiber used in the present invention is imparted with buckling and crimping. This is because buckling and crimping improves the entanglement between fibers when a short fiber non-woven fabric is formed, and enables high density and high entanglement. A normal stuffing box type crimper is preferably used to impart buckling crimp to the composite fiber, but in order to obtain a preferable crimp retention coefficient in the present invention, the treated fineness, crimper temperature, crimper weighting and It is a preferable embodiment to adjust the pushing pressure and the like as appropriate.

The crimp retention coefficient of the ultrafine fiber-expressing fiber to which buckling crimp is imparted is preferably in the range of 3.5 or more and 15 or less, and more preferably in the range of 4 or more and 10 or less. When the crimp retention coefficient is 3.5 or more, the rigidity of the non-woven fabric in the thickness direction is improved when the non-woven fabric is formed, and it is possible to maintain the entanglement property in the entanglement process such as needle punching. Further, by setting the crimp retention coefficient to 15 or less, the crimping property is excellent in the fiber web in carding without excessive crimping.

The crimp retention coefficient referred to here is expressed by the following equation.
・ Crunch retention coefficient = (W / L-L ₀ ) ^1/2
-W: Crispy extinction load (load at the time when the crimp is fully extended: mg / dtex)
・ L: Fiber length (cm) under crimp extinction load
Fiber length (cm) under L0: 6 mg / dtex. Mark 30.0 cm.

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

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

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

Specifically, in the method for measuring the shrinkage rate, first, a load of 50 mg / dtex is applied to a bundle of composite fibers, and 30.0 cm is marked (L ₀ ). Then, the treatment is carried out in hot water at a temperature of 98 ° C. for 10 minutes, the length (L ₁ ) before and after the treatment is measured, and (L _{0 −} L ₁ ) / L ₀ × 100 is calculated. The measurement is carried out 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 fibers / bundle or more and 1000 fibers / bundle or less, and more preferably 10 fibers / bundle or more and 800 fibers / bundle or less. When the number of fibers is 8 fibers / bundle or more, the ultrafine fibers tend to have sufficient denseness, and for example, mechanical properties such as wear tend to be improved. Further, when the number of fibers is 1000 fibers / bundle or less, the fiber opening property at the time of fluffing is improved, the fiber distribution on the fluffing surface becomes uniform, and it becomes easy to obtain a better surface quality of the sheet-like material.

[Fibrous base material]
The fibrous base material used in the present invention comprises the ultrafine fibers. It is permissible that the fibrous base material contains ultrafine fibers of different raw materials.

As a specific form of the fibrous base material, a non-woven fabric formed by entwining each of the ultrafine fibers or a non-woven fabric formed by entwining fiber bundles of ultrafine fibers can be used. Among them, a non-woven fabric formed by entwining fiber bundles of ultrafine fibers is preferably used from the viewpoint of strength and texture of a sheet-like material. From the viewpoint of flexibility and texture, a non-woven fabric in which the ultrafine fibers constituting the fiber bundle of the ultrafine fibers are appropriately separated from each other and has voids is preferably used. As described above, the non-woven fabric in which the fiber bundles of the ultrafine fibers are entangled can be obtained, for example, by entwining the ultrafine fiber-expressing fibers in advance and then expressing the ultrafine fibers. Further, the non-woven fabric in which the ultrafine fibers constituting the fiber bundle of the ultrafine fibers are appropriately separated from each other and have voids is, for example, a sea-island type composite fiber capable of forming voids between the island components by removing the sea component. It can be obtained by using it.

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

When a short fiber non-woven fabric is used, the fiber length of the short fibers is preferably in the range of 25 mm or more and 90 mm or less. When the fiber length is 25 mm or more, more preferably 35 mm or more, still more preferably 40 mm or more, a sheet-like material having excellent wear resistance is obtained by entanglement. Further, when the fiber length is 90 mm or less, more preferably 80 mm or less, still more preferably 70 mm or less, a sheet-like material having more excellent texture and surface quality can be obtained.

In the present invention, when a non-woven fabric is used as the fibrous base material, the woven fabric or knitted fabric can be inserted, laminated, or lined inside the non-woven fabric for the purpose of improving the 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.

Examples of the fibers constituting the woven fabric 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. Recycled fibers and natural fibers such as cotton and linen can be used.

Methods for obtaining a non-woven fabric that can be used for the fibrous base material constituting the sheet-like material of the present invention include a method of entwining a composite fiber web with a needle punch or a water jet punch, a spunbond method, a melt blow method, and papermaking. The law can be adopted. Above all, a method that undergoes treatment such as needle punching or water jet punching is preferably used in order to obtain the above-mentioned aspect of the ultrafine fiber bundle.

As the non-woven fabric, as described above, the non-woven fabric and the woven or knitted fabric may be laminated and integrated, and a method of integrating these with a needle punch, a water jet punch or the like is preferably used.

In the needle used for the needle punching process, the number of needle barbs (cutting) is preferably 1 or more and 9 or less. By preferably using one or more needle barbs, efficient fiber entanglement becomes possible. On the other hand, fiber damage can be suppressed by preferably using 9 or less needle barbs.

The number of composite fibers caught in the barb is determined by the shape of the barb and the diameter of the composite fibers. Therefore, the barb shape of the needle used in the needle punching process has a kickup 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 slow strength. Is preferably 0.5 mm or more and 1.0 mm or less.

The number of punches is preferably 1000 / cm ² or more and 8000 / cm ² or less. By setting the number of punches to preferably 1000 / cm ² or more, fineness can be obtained and a highly accurate finish can be obtained. On the other hand, by setting the number of punches to preferably 8000 / cm ² or less, deterioration of workability, fiber damage and strength reduction can be prevented.

Further, when the water jet punching treatment is performed, it is preferable that the water is performed in a columnar flow state. Specifically, it is a preferable embodiment that 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.

Apparent density of the nonwoven fabric after needle punching or water jet punching is preferably 0.15 g / cm ³ or more 0.45 g / cm ³ or less. By setting the apparent density to preferably 0.15 g / cm ³ or more, it becomes easy for the sheet-like material to obtain sufficient morphological stability and dimensional stability. On the other hand, by setting the apparent density to preferably 0.45 g / cm ³ or less, it is possible to easily maintain a sufficient space for imparting polyurethane.

From the viewpoint of densification, the non-woven fabric thus obtained is preferably shrunk by dry heat, moist heat, or both to further increase the density. Further, the non-woven fabric can be compressed in the thickness direction by calendar processing or the like.

When a sea-island type composite fiber is used, the desealing treatment for removing the sea component of the fiber is performed before or / and before the application of the aqueous dispersion containing the polymer elastic body having a hydrophilic group to the fibrous substrate. It can be done after granting. If the desealing treatment is performed before the addition of the aqueous dispersion, the polymer elastic body tends to be in direct contact with the ultrafine fibers, and the ultrafine fibers can be strongly gripped, so that the abrasion resistance of the sheet-like material is improved.

On the other hand, by adding the ultrafine fiber and an inhibitor such as a cellulose derivative or polyvinyl alcohol (hereinafter, may be abbreviated as PVA) before the addition of the aqueous dispersion, and then applying the aqueous dispersion, the fine fiber and the high value are obtained. The adhesion of the molecular elastic resin can be lowered, and a more flexible texture can be achieved.

The inhibitory application can be carried out either before or after the desealing treatment of the fibers of the sea-island structure. By applying an inhibitor before the desealing treatment, the morphological holding power of the fibrous base material can be enhanced even when the basis weight of the fibers is lowered and the tensile strength of the sheet is lowered. Therefore, in addition to being able to stably process a thin sheet, it is possible to increase the thickness retention rate of the fibrous base material in the desealing treatment step, and it is possible to suppress the increase in density of the fibrous base material. On the other hand, since it is possible to realize a high density of the fibrous base material by applying the inhibitor after the desealing treatment, it is preferable to appropriately adjust it according to the purpose.

As the inhibitor, the fibrous base material has a high reinforcing effect and is difficult to elute into water.
PVA is preferably used. Among PVAs, it is more water-difficult from the viewpoint that the inhibitor can be less likely to be eluted when an aqueous dispersion containing a polymer elastic body having a hydrophilic group is applied, and the adhesion between the ultrafine fibers and the polymer elastic body can be inhibited. It is a more preferred embodiment to apply a high degree of saponification PVA.

The high degree of saponification PVA preferably has a degree of saponification of 95% or more and 100% or less, and more preferably 98% or more and 100% or less. By setting the degree of saponification to 95% or more, elution at the time of applying the polymer elastic material dispersion having a hydrophilic group can be suppressed.

The degree of polymerization of PVA is preferably 500 or more and 3500 or less, and 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 having a high degree of saponification when the polymer elastic material dispersion is applied. Further, by setting the degree of polymerization of PVA to 3500 or less, the viscosity of the highly saponified PVA liquid does not become too high, and the highly saponified PVA can be stably imparted to the fibrous substrate.

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. By setting the amount of PVA applied to 0.1% by mass or more, a sheet-like material having good flexibility and texture can be obtained, and by setting the amount of PVA applied to 50% by mass or less, workability is good and resistance is achieved. A sheet-like material having good physical characteristics such as abrasion resistance can be obtained.

[Polymer elastic body]
In the sheet-like material of the present invention, examples of the polymer elastic body having a hydrophilic group include a water-dispersible silicone resin, a water-dispersible acrylic resin, a water-dispersible urethane resin, and a copolymer thereof. Among them, a water-dispersible polyurethane resin is preferably used from the viewpoint 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. Further, in order to improve the stability of the aqueous dispersion of the aqueous dispersion polyurethane resin (hereinafter referred to as the aqueous dispersion polyurethane dispersion), it is preferable to use an active hydrogen component-containing compound having a hydrophilic group in combination. The case where a water-dispersed polyurethane resin is used as the polymer elastic body will be described below.

(1) Each reaction component of the water-dispersible polyurethane resin First, each reaction component of the water-dispersible polyurethane resin will be described.

(1-1) Polymer polyols Examples of the polymer polyols that can be used in the sheet-like product of the present invention include polyether-based polyols, polyester-based polyols, and polycarbonate-based polyols.

As the polyether polyol, a polyol obtained by adding and polymerizing a monomer such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and cyclohexylene using a polyhydric alcohol or polyamine as an initiator, and a polyol obtained by addition and polymerization. Examples thereof include a polyol obtained by ring-opening polymerization of the monomer using a protonic acid, Lewis acid, a cation catalyst or the like as a catalyst. Specific examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like, and copolymerized polyols combining them.

Examples of the polyester-based polyol include a polyester polyol obtained by condensing various low molecular weight polyols with a polybasic acid, a polyol obtained by depolymerizing a lactone, 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, and 1.8-. Linear alkylene glycols such as octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 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 aromatic divalents such as 1,4-bis (β-hydroxyethoxy) benzene. One or more selected from alcohol and the like can be mentioned. Further, an adduct obtained by adding various alkylene oxides to bisphenol A can also be used as a low molecular weight polyol.

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

Examples of the polycarbonate-based polyol include compounds obtained by reacting the polyol with a carbonate compound such as dialkyl carbonate or diaryl carbonate.

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

In the sheet-like material of the present invention, it is preferable that the polymer elastic body contains a polyether diol as a constituent component. In addition, in this specification, "containing as a constituent component" means that it is contained as a monomer component and an oligomer component constituting a polymer elastic body. Since the degree of freedom of the ether bond of the polyether diol is high, the glass transition temperature is low and the cohesive force is weak, so that polyurethane having excellent flexibility can be easily obtained.

In the sheet-like material of the present invention, the polymer elastic body has a polymer elastic body A having a hydrophilic group containing a polyether diol as a constituent component and a high molecular weight elastic body having a hydrophilic group containing a polycarbonate diol as a constituent component. It is preferably composed of a molecular elastic body B. A polymer elastic body A having a hydrophilic group containing a polyether diol as a component having excellent flexibility, and a hydrophilic group containing a polycarbonate diol as a component having excellent durability against external stimuli such as light and heat. By including both of the polymer elastic bodies B inside the sheet-like material, it becomes easy to obtain a sheet-like material that is flexible and has excellent durability.

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 5000 or less, more preferably 4000 or less, it is possible to easily maintain the strength of polyurethane as a binder.

(1-2) Organic diisocyanates The organic diisocyanates used in the present invention include aromatic diisocyanates having 6 or more and 20 or less carbon atoms (excluding carbons in NCO groups, the same applies hereinafter) and 2 or more and 18 or less carbon atoms. Aliphatic diisocyanates, alicyclic diisocyanates having 4 to 15 carbon atoms, aromatic aliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates (carbodiimide modified products, urethane modified products, uretdione modified products, etc.). ) And a mixture of two or more of these.

Specific examples of the aromatic diisocyanate having 6 or more and 20 or less carbon atoms include 1,3- and / or 1,4-phenylenediocyanate, 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' Examples thereof include −dimethyl-4,4'-diisocyanatodiphenylmethane, and 1,5-naphthylene diisocyanate.

Specific examples of the aliphatic diisocyanate having 2 or more and 18 or less carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2,6. -Diisocyanatomethyl caproate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexaate and the like.

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

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

Of these, the preferred organic diisocyanate is an alicyclic diisocyanate. A particularly preferable organic diisocyanate is dicyclohexylmethane-4,4'-diisocyanate.

(1-3) Chain extender Examples of the chain extender used in the present invention include water, "ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, and diethylene glycol." And neopentyl glycol, etc., low molecular weight diols, 1,4-bis (hydroxymethyl) cyclohexane, etc., alicyclic diols, 1,4-bis (hydroxyethyl) benzene, etc., aromatic diols, ethylenediamine, etc. Aliphatic diols such as "isophorone diols", alicyclic diamines such as "isophorone diols", aromatic diamines such as "4,4-diaminodiphenylmethane", aromatic aliphatic diamines such as "xylene diamines", and alkanols "ethanolamine etc." Examples include amines, hydrazines, dihydrazides such as "dihydrazide adipate", and mixtures of two or more of these.

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

(2) Additives for water-dispersible polyurethane resin In the present invention, it is important to contain a monovalent cation-containing inorganic salt and a thickener in the water dispersion containing the water-dispersible polyurethane for the reason described later. ..

In addition, if necessary, colorants such as titanium oxide, UV absorbers (benzophenone-based, benzotriazole-based, etc.) and antioxidants [4,5-butylidene-bis (3-methyl-6-1-butylphenol), etc. Dophenol; organic phosphite such as triphenyl phosphite and trichloroethyl phosphite] and other stabilizers, inorganic fillers (calcium carbonate, etc.) and the like can be contained.

(3) Structure of Water-Dispersible Polyurethane Resin In the water-dispersible polyurethane used in the present invention, examples of the component that causes the polyurethane to contain a hydrophilic group include a hydrophilic group-containing active hydrogen component. Examples of the hydrophilic group-containing active hydrogen component include compounds containing a nonionic group and / or an anionic group and / or a cationic group and active hydrogen.

Examples of the compound having a nonionic group and active hydrogen 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 9000 in the side chain. And triols such as trimethylolpropane and trimethylolbutane can be mentioned.

Examples of the compound having an anionic group and active hydrogen include carboxyl group-containing compounds such as 2,2-dimethylol propionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylol valerate and derivatives thereof, and 1 , 3-Phenylenediamine-4,6-disulfonic acid, 3- (2,3-dihydroxypropoxy) -1-propanesulfonic acid and other compounds containing sulfonic acid groups and their derivatives, and neutralizing these compounds. Examples include salts neutralized with an agent.

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

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

The hydrophilic group-containing active hydrogen component used in the polyurethane molecule is 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and from the viewpoint of mechanical strength and dispersion stability of the water-dispersed polyurethane resin. It is preferable to use these neutralizing salts.

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

In the sheet-like material of the present invention, the polymer elastic body having a hydrophilic group has an N-acylurea bond and / or an isourea bond. That is, in the sheet-like material of the present invention, the polymer elastic body has a hydrophilic group and an N-acylurea bond and / or an isourea bond.

When an aqueous dispersion type polyurethane resin is used as the polymer elastic body having a hydrophilic group, the N-acylurea bond and / or the isourea bond is, for example, a hydroxyl group and / or a carboxyl existing as the above-mentioned 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 by N-acylurea bond and / or isourea bond, which is excellent in physical properties such as light resistance, heat resistance, and abrasion resistance, and flexibility is imparted into the molecule of the polymer elastic body having a hydrophilic group. However, it is possible to dramatically improve physical properties such as abrasion resistance while maintaining the flexibility of the sheet-like material. The presence of the N-acylurea group or isourea group in the polymer elastic body is a mapping process such as time-of-flight secondary ion mass spectrometry (TOF-SIMS analysis) on the cross section of the sheet-like material. Can be analyzed by doing.

The number average molecular weight of the polymer elastic body having a hydrophilic group used in the present invention is preferably 20,000 or more from the viewpoint of resin strength, and 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 polymer elastic body having a hydrophilic group can be determined by gel permeation chromatography, and is measured, for example, under the following conditions.
・ Equipment: HLC-8220 manufactured by Tosoh Corporation
-Column: Tosoh TSKgel α-M
-Solvent: N, N-dimethylformamide (DMF)
・ Temperature: 40 ℃
-Calibration: Polystyrene The polymer elastic body having a hydrophilic group used in the present invention appropriately grips fibers in a sheet-like material, and preferably has fluff on at least one side of the sheet-like material. It is a preferred embodiment that it exists inside the fibrous substrate.

[Sheet]
The sheet-like material of the present invention has a length of 10 μm or more from the adhesive portion with the ultrafine fibers in a range of 500 μm square including 500 or more cross-sectional portions of the ultrafine fibers in the cross section obtained by cutting the sheet-like material in the thickness direction. The number of polymer elastic bodies is 20 or more, and the maximum width of the portion within 10 μm from the portion bonded to the ultrafine fiber is more than 0 μm and 5 μm or less. In the present specification, "polymer elasticity in which the length from the portion bonded to the ultrafine fibers is 10 μm or more and the maximum width of the portion within 10 μm from the bonded portion with the ultrafine fibers exceeds 0 μm and is 5 μm or less. The "body" may be referred to as a "filamentous polymer elastic body".

Since the filamentous polymer elastic body has a weak force to restrain the ultrafine fibers, it contributes to the softening of the sheet-like material, that is, the improvement of the texture. Further, when the sheet-like material has a nap layer, the filamentous polymer elastic body has a small domain size of the polymer elastic body, and therefore has excellent fluff expression, resulting in a glossy feeling.

The number of filamentous polymer elastic bodies is preferably 30 or more.

The filamentous polymer elastic body is a cross section of ultrafine fibers in five sheets obtained by observing a cross section cut in the thickness direction of a sheet-like object at a magnification of 500 using a scanning electron microscope (VE-7800 type manufactured by SEM KEYENCE). The average of the number of filamentous polymer elastic bodies existing in the range of 500 μm square including 500 or more is calculated. Here, the cross-sectional portion of the ultrafine fibers of 500 or more means that the number of ultrafine fibers in which the cut cross section can be observed in the cross section of the sheet-like material is 500 or more.

When the polymer elastic body is bonded to three or more ultrafine fibers at the same time, the length from the bonded portion to the branched portion of the polymer elastic body to the ultrafine fibers is 10 μm or more, and from the bonded portion with the ultrafine fibers. When the maximum width of the portion within 10 μm exceeds 0 μm and is 5 μm or less, it is defined as a filamentous polymer elastic body. Moreover, the maximum width here refers to the maximum width in the observation cross section ignoring the depth.

FIG. 2 shows an example of a method for defining a filamentous polymer elastic body in a sheet-like material of the present invention. In FIG. 2, the polymer elastic body 1 that adheres to the ultrafine fibers 3 and 4 has a maximum width of 0.6 μm, and the length a, that is, the distance from the adhesive portion A with the ultrafine fibers to the adhesive portion B with the ultrafine fibers is 14 μm. .. Therefore, the polymer elastic body 1 can be regarded as a filamentous polymer elastic body. Further, the portion of the polymer elastic body 2 that adheres to the ultrafine fibers 3, 4, and 5 has a maximum width of 0.6 μm, and the length b from the ultrafine fiber adhesive portion to the branched portion is 14 μm, which is filamentous. It can be regarded as a polymer elastic body. Similarly, the portion having a length c has a maximum width of 0.6 μm and a length c of 16 μm, and can be regarded as a filamentous polymer elastic body. On the other hand, in the portion having a length d, the maximum width is 2 μm, and the length d from the ultrafine fiber adhesive portion to the branched portion is 8 μm, which is less than 10 μm. Therefore, the polymer elastic body having a length d cannot be regarded as a filamentous polymer elastic body. From the polymer elastic body 2, there are two filamentous polymer elastic bodies.

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

As a method for increasing the number of filamentous polymer elastic bodies to 20 or more, for example, a 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 coagulated and dried. There is a method of obtaining a sheet-like material.

In the present invention, it is preferable that the sheet-like material 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, a sheet-like material having a more elegant surface appearance and a glossy feeling can be obtained. As a principle of improving the glossiness, it is presumed that by setting the surface coverage in the above range, the surface of the napped layer tends to be smooth, and a surface having a high specular reflectance of light can be easily obtained. That is, if the fiber portions on the surface are dense, the reflectance of light increases and a glossy feeling is generated.

The surface coverage of the napped surface was magnified to an observation magnification of 30 to 70 times so that the presence of fluffy fibers could be seen by SEM, and the ratio of the total area of the napped portion per total area of 4 mm ² was calculated using image analysis software. The calculated value was used as the average value of the numerical values for the five SEM images as the nap coverage. The ratio of the total area can be calculated by binarizing the captured SEM image by setting the napped portion and the non-raised portion to a threshold value of 100 using the image analysis software "ImageJ". Further, in the calculation of the napped coverage rate, when a substance other than napped hair is calculated as napped hair and has a great influence on the napped hair coverage rate, the image is manually edited and that portion is calculated as a non-raised hair portion.

As the image analysis system, the above-mentioned image analysis software "ImageJ" is exemplified, but if the image analysis system is composed of image processing software having a function of calculating a predetermined pixel area ratio, the image analysis software Not limited to "ImageJ". The image processing software "ImageJ ver. 1.8.0_112" is a universal software and was developed by the National Institutes of Health. The image processing software "ImageJ" has a function of specifying a necessary area for the captured image and performing pixel analysis.

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

The method for producing a sheet-like substance of the present invention is a method for producing a sheet-like substance of the present invention, which is a step of impregnating a fibrous substrate with an aqueous dispersion, and coagulates with a coagulation solvent having a pH of 1 or more and 3 or less. The fibrous material comprises a step of coagulating by an acid coagulation method for treating or a hot water coagulation method for coagulating in hot water of 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 composed of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion is a polymer elastic body having a hydrophilic group, a cross-linking agent, and a polymer elastic body solid having the 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 with respect to 100 parts by mass.

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

The concentration of the polymer elastic body having a hydrophilic group in the aqueous dispersion (the content of the polymer elastic body having a hydrophilic group with respect to the aqueous dispersion) is determined from the viewpoint of storage stability of the aqueous dispersion. Assuming that the total mass of the liquid is 100% by mass, it is preferably 10% by mass or more and 50% by mass or less, and more preferably 15% by mass or more and 40% by mass or less.

Further, the aqueous dispersion may contain 40% by mass or less of a water-soluble organic solvent with respect to the aqueous dispersion in order to improve storage stability and film-forming property, but it is necessary to protect the film-forming environment. 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 product of the present invention, a monovalent cation-containing inorganic substance having a hydrophilic group in a aqueous dispersion is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of a solid content of a polymer elastic body having a hydrophilic group. Contains salt. By containing a monovalent cation-containing inorganic salt, it is possible to impart heat-sensitive coagulation to the aqueous dispersion. In the present invention, the heat-sensitive coagulation property means a property that when the water dispersion is heated, the fluidity of the water dispersion decreases and solidifies when a certain temperature (heat-sensitive coagulation temperature) is reached.

In the method for producing a sheet-like product of the present invention, the fibrous substrate is impregnated with an aqueous dispersion, and then coagulated and dried. Since the polymer elastic body having a hydrophilic group easily swells in an aqueous solution, coagulation is not completely completed after the coagulation treatment. Therefore, when the polymer elastic body having a hydrophilic group does not have heat-sensitive coagulability, the polymer elastic body that has not been coagulated into ultrafine fibers when the sheet is dried covers the fiber periphery. It has a structure that strongly restrains movement. This is because the solidification proceeds in a state where the polymer elastic body is unevenly distributed around the fiber as the migration occurs and the water evaporates, which migrates to the sheet surface as the water evaporates. As a result, the texture of the sheet-like material is cured.

The heat-sensitive coagulation temperature of the aqueous dispersion is preferably 55 ° C. or higher and 80 ° C. or lower, and 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 becomes good, and it becomes easy to suppress the adhesion of the polymer elastic body to the machine during operation. Further, by setting the heat-sensitive coagulation temperature to 80 ° C. or lower, it is possible to suppress the migration phenomenon of the polymer elastic body to the surface layer of the fibrous base material, and further, the polymer elasticity before the evaporation of water from the fibrous base material. As the solidification of the body progresses, it is possible to form a structure similar to that obtained by wet-solidifying a solvent-based polymer elastic body, that is, a structure in which the polymer elastic body strongly does not restrain the fibers, and has good flexibility. It is possible to achieve sexuality and repulsion.

The monovalent cation-containing inorganic salt is preferably sodium chloride and / or sodium sulfate. In the conventional method, inorganic salts having divalent cations such as magnesium sulfate and calcium chloride have been preferably used as the heat-sensitive coagulant, but these inorganic salts can improve the stability of the aqueous dispersion even when added in a small amount. Since it has a large effect, it is difficult to strictly control the heat-sensitive gelation temperature by adjusting the amount of the polymer elastic material added, and when adjusting the aqueous dispersion of the polymer elastic material having a hydrophilic group. There were issues such as concerns about gelation during storage. On the other hand, the monovalent cation-containing inorganic salt having a small ionic valence has a small effect on the stability of the aqueous dispersion, and heat-sensing while ensuring the stability of the aqueous dispersion by adjusting the addition amount. The solidification temperature can be strictly controlled.

In the method for producing a sheet-like product of the present invention, a monovalent cation-containing inorganic salt is contained in an amount of 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of a solid content of a polymer elastic body 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 polymer elastic body having a hydrophilic group act uniformly on the polymer elastic particle particles, thereby causing specific heat sensitivity. Solidification can be completed quickly at the solidification temperature. As a result, a more remarkable effect can be obtained in advancing the coagulation of the polymer elastic body in a state where 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-solidifying a solvent-based polymer elastic body, and to achieve good flexibility and a feeling of repulsion. On the other hand, when the content is 50 parts by mass or less, an appropriate continuous coating structure of the polymer elastic body can be left, and deterioration of physical properties can be suppressed. In addition, the stability of the aqueous dispersion can be maintained.

In the method for producing a sheet-like product of the present invention, the aqueous dispersion contains a cross-linking agent. By introducing a three-dimensional network structure into the polymer elastic body with a cross-linking agent, physical properties such as wear resistance can be improved. Further, when used in combination with the above-mentioned monovalent cation-containing inorganic salt, the sheet-like material can be softened by controlling the adhesive structure between the polymer elastic body and the fiber, and at the same time, the high physical characteristics of the sheet-like material can be achieved.

Since the polymer elastic body obtained after the reaction has excellent light resistance, heat resistance, abrasion resistance, and good flexibility, it is preferable that the cross-linking agent is a carbodiimide-based cross-linking agent.

Furthermore, by using a thickener in combination with the water-dispersed polyurethane dispersion, the water-dispersed polyurethane dispersion impregnated in the fibrous substrate does not diffuse into the liquid bath due to the influence of the viscosity of the liquid, and the polyurethane It is possible to suppress the dropout during the solidification process and achieve a solidification process with excellent productivity.

As the thickener contained in the aqueous dispersion, nonionic, anionic, cationic and amphoteric thickeners can be applied. Above all, it is preferable that the thickener is a nonionic thickener because it does not easily affect the stability of the aqueous dispersion.

The type of thickener can be selected from an association type thickener and a water-soluble polymer type thickener.

As the association type thickener, urethane-modified compounds, acrylic-modified compounds, copolymer compounds thereof and the like can be applied.

Examples of the water-soluble polymer-type thickener include natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds.

Natural polymer compounds include nonionic compounds such as tamarind gum, guar gum, roast bean gum, tragant gum, starch, dextrin, gelatin, agarose, casein and curdlan, and xanthan gum, carrageenan, arabic gum, pectin, collagen and chondroitin. Examples thereof include anionic ones such as sodium sulfate, sodium hyaluronate, carboxymethyl starch and starch phosphate, and cationic ones such as cationic starch and chitosan.

Semi-synthetic polymers include nonionic ones such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, soluble starch and methyl starch, and anionic ones such as carboxymethyl cellulose, carboxymethyl starch and arginate. Compounds include.

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. Examples thereof include sexual compounds and cationic compounds such as dimethylaminoethyl (meth) acrylate quaternary salt, dimethyldialylammonium chloride, polyamidine, polyvinyl imidazoline, and polyethyleneimine.

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

In the method for producing a sheet-like product of the present invention, coagulation after imparting a polymer elastic body 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 80 ° C or more and 100 ° C or less. A hot water coagulation method is used in which coagulation treatment is performed with hot water. Another coagulation method, for example, a dry heat coagulation method, is a method of heat-treating a sheet impregnated with a polymer elastic body having a hydrophilic group with a hot air dryer or the like, and undergoes a process in which water evaporates from the sheet-like material. Solidification of the polymer elastic body progresses. Therefore, the polymer elastic bodies tend to aggregate with each other, and the domain size becomes large. On the other hand, in the present invention, since the coagulation treatment is performed in the liquid bath, the coagulation proceeds while the polymer elastic body diffuses inside the sheet. Therefore, the domain size of the polymer elastic body becomes small, and the sheet tends to have a glossy feeling.

In the method for producing a sheet-like product of the present invention, the coagulation solvent 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 polymer elastic body can be easily promoted. Further, by setting the pH to 1 or more, it becomes easy to prevent deterioration of the polymer elastic body.

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

Further, the temperature of the coagulation solvent in the hot water coagulation method is preferably 80 ° C. or higher and 100 ° C. or lower, and more preferably, coagulation at 85 ° C. or higher and 95 ° C. or lower can achieve a porous structure.

Further, in the method for producing a sheet-like product of the present invention, the aqueous dispersion contains a cross-linking agent, but 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. By performing the treatment, the cross-linking reaction can be sufficiently promoted and the physical properties can be improved. Further, by setting the heating temperature to 180 ° C. or lower, thermal deterioration of the polymer elastic body can be suppressed.

In addition, the method for producing a sheet-like product of the present invention may further include a step of removing PVA from a fibrous base material to which a polymer elastic body having a hydrophilic group is provided, if necessary. By removing PVA from the fibrous base material after imparting a polymer elastic body having a hydrophilic group, a flexible sheet-like material can be easily obtained. The method for removing PVA is not particularly limited, but for example, it is preferable to dissolve and remove the sheet by immersing the sheet in hot water at 60 ° C. or higher and 100 ° C. or lower and squeezing it with a mangle or the like as necessary. is there.

In the present invention, at least one surface of the sheet-like material may be brushed to form naps on the surface. The method for forming naps is not particularly limited, and various methods usually performed 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. Therefore, the nap length is preferably 0.2 mm or more and 1 mm or less.

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

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, dyeing to the fibers can be efficiently performed. On the other hand, by setting the dyeing temperature to 150 ° C. or lower, more preferably 130 ° C. or lower, deterioration of the polymer elastic body 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, if it is a polyester fiber, a disperse dye can be used, and a polyamide fiber can be used. If so, acid dyes and gold-containing dyes can be used, and combinations thereof can be used. When dyed with a disperse dye, reduction cleaning may be performed after dyeing.

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

The sheet-like material of the present invention is an interior material, a shirt, a jacket, which has a very elegant appearance as a skin material for furniture, chairs and wall materials, seats, ceilings and interiors in vehicle interiors such as automobiles, trains and aircraft. Industry of uppers, trims, bags, belts, wallets, etc. of shoes such as casual shoes, sports shoes, men's shoes and women's shoes, and clothing materials used for some of them, wiping cloths, polishing cloths, CD curtains, etc. It can be suitably used as a material.

Next, the sheet-like material of the present invention and the method for producing the same will be described in more detail by way of examples, but the present invention is not limited to these examples.

[Evaluation methods]
(1) Average single fiber fineness of sheet-like material:
A cross section perpendicular to the thickness of the sheet containing fibers was observed at 3000 times using a scanning electron microscope (VE-7800 type manufactured by SEM KEYENCE), and randomly extracted within a field of view of 30 μm × 30 μm. The diameters of the 50 single fibers were measured in μm units up to the first fraction. However, this was done at three places, the diameters of a total of 150 single fibers were measured, and the average value was calculated up to the first decimal place. When fibers having a fiber diameter of more than 50 μm are mixed, the fibers are excluded from the measurement target of the average fiber diameter because they do not correspond to ultrafine fibers. Further, when the ultrafine fiber has a deformed cross section, as described above, the diameter of the single fiber is obtained by first measuring the cross-sectional area of the single fiber and calculating the diameter when the cross section is regarded as a circle. The average value using this as the population was calculated and used as the average single fiber fineness.

(2) Flexibility of sheet-like material:
Based on the A method (45 ° cantilever method) described in 8.21.1 of 8.21 "Stiffness and softness" of JIS L 1096: 2010 "Fabric test method for woven fabrics and knitted fabrics", in the vertical and horizontal directions. Create five 2 x 35 cm test pieces, place them on a horizontal table with a slope at an angle of 45 °, slide the test pieces, and read the scale when the center point of one end of the test piece touches the slope. The average value of 5 sheets was calculated.

(3) Coagulation temperature of aqueous dispersion of polymer elastic body having hydrophilic group 20 g of aqueous dispersion containing polymer elastic body having hydrophilic group prepared in each Example and Comparative Example is tested with an inner diameter of 12 mm. Put it in a tube, insert the thermometer so that the tip is below the liquid level, seal the test tube, and put it in a warm water bath at a temperature of 95 ° C., an aqueous dispersion of a polymer elastic body having a hydrophilic group. Soaked so that the liquid level of the water bath was lower than the liquid level of the hot water bath. While checking the rise in the temperature inside the test tube with a thermometer, pull up the test tube for a time of 5 seconds or less each time, and whether or not the water level of the aqueous dispersion of the polymer elastic body having a hydrophilic group is fluid. The solidification temperature was defined as the temperature at which the liquid level of the aqueous dispersion of the polymer elastic body having a hydrophilic group lost its fluidity by shaking to the extent that the above was confirmed. This measurement was carried out three times for each type of aqueous dispersion of a polymer elastic body having a hydrophilic group, and the average value was calculated.

(4) Identification of Bonded Species in Polymer Elastic Body The polymer elastic body separated from the above sheet-like material was identified by infrared spectroscopic analysis using FT / IR 4000 series manufactured by JASCO Corporation. Identified.

(5) Appearance grade of sheet-like material:
The surface quality of the obtained sheet-like material was evaluated by 10 panelists, evaluated according to the following criteria, and the evaluation result with the largest number of people was adopted. In the evaluation of the surface quality, as shown in FIG. 4, the sheet-like object 12 is placed on the inspection table 11 at a position parallel to the floor surface 10, and the line 13 connecting the visually confirmed position and the sheet-like object is formed. The sheet-like object 14 was visually confirmed and judged at an angle of 45 ° from the inspection table plane with respect to the sheet-like object 14 so that the distance was 50 cm. Further, on the inspection table, a 32W fluorescent lamp 15 was installed 150 cm above the upper surface of the inspection table in the vertical direction. The surface quality evaluation was carried out by placing the sheet-like material 12 directly below the fluorescent lamp 15, that is, at a position where a perpendicular line 16 from the sheet-like material to the fluorescent lamp can be drawn. The appearance quality was good in grades 4 to 5.
Grade 5: The dispersed state of the fibers is good and the appearance with a glossy feeling is good. When the sheet has a fluff layer, there is uniform fiber fluff.
Grade 4: Evaluation between grade 5 and grade 3.
Grade 3: The dispersed state of the fibers is somewhat poor, but the appearance is reasonably good, but there is no glossiness. If the sheet has a nap layer, it is not uniform but has fluff of fibers.
Level 2: Evaluation between grade 3 and grade 1.
Grade 1: Overall, the dispersed state of the fibers is very poor, and the appearance is poor. When the sheet-like material has a nap layer, there are many parts where fluff does not appear due to unevenness.

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

[Reference Example 2: Preparation of aqueous dispersion Wb of polymer elastic body b having a hydrophilic group]
Polyhexamethylene carbonate having Mn of 2,000 in the polyol (denoted as PHC in the table), hydrogenated MDI in isocyanate, and diol compounds having polyethylene glycol in the side chain as components containing hydrophilic groups and 2,2-di. A prepolymer was prepared in an acetone solvent using methylol propionic acid. Ethylene glycol, ethylenediamine and water were added as chain extenders, and the mixture was stirred. Acetone was removed by reducing the pressure to obtain an aqueous dispersion Wb of the polymer elastic body b having a hydrophilic group. The polymer elastic body b is a polymer elastic body corresponding to the polymer elastic body B.

[Example 1]
(Non-woven fabric)
As the sea component, polyethylene terephthalate obtained by copolymerizing 8 mol% of sodium 5-sulfoisophthalate was used, and as the island component, polyethylene terephthalate was used. The sea component was 43% by mass and the island component was 57% by mass. Sea-island type composite fibers having 16 islands / 1 filament and an average fiber diameter of 20 μm were obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber web was formed through a curd and a cloth wrapper, and a non-woven fabric was obtained by needle punching. The non-woven 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 non-woven fabric for fibrous base material is impregnated with a 10% by mass aqueous solution of PVA (NM-14 manufactured by Nippon Synthetic Chemical Co., Ltd.) having a degree of saponification of 99% and a degree of polymerization of 1400, and heated and dried at a temperature of 140 ° C. for 10 minutes. Then, a PVA-imparting sheet in which the amount of PVA adhered to the fiber mass of the non-woven fabric for a fibrous base material was 30% by mass was obtained.

(Fiber ultrafineness)
The obtained PVA-imparting sheet was immersed in an aqueous solution of sodium hydroxide having a concentration of 8 g / L heated to a temperature of 95 ° C. and treated for 30 minutes to remove the sea component of the sea-island type composite fiber. PVA-imparted ultrafine fiber non-woven fabric) was obtained.

(Addition of polymer elastic resin)
A nonionic thickener (guar gum) is added to the water-dispersed polyurethane dispersion Wa prepared so that the polyurethane solid content concentration is 20% with respect to the solid content 100% by mass of the polymer elastic body a having a hydrophilic group. The active ingredient of "Neosoft G" manufactured by Co., Ltd.] was added in an amount of 1% by mass based on the solid content of polyurethane, and sodium sulfate (described as "Na ₂ SO ₄ " in Table 1) was added in an amount of 30% by mass as a heat-sensitive coagulant. 3% by mass of the cross-linking agent was added, and the whole was adjusted to 17% by mass with water to obtain an aqueous dispersion containing the polymer elastic body a having a hydrophilic group. The heat-sensitive solidification temperature was 65 ° C. The obtained PVA-imparted ultrafine fiber non-woven fabric is immersed in the aqueous dispersion, then subjected to acid coagulation treatment, that is, treatment in a liquid of pH 2 for 10 minutes, and then dried with hot air at a drying temperature of 120 ° C. for 30 minutes with respect to the island component mass of the non-woven fabric. A polymer elastic resin-imparted sheet having a thickness of 2.0 mm and having a polyurethane mass of 45% by mass was obtained.

(Removal of reinforcing resin)
The obtained polymer elastic resin-imparted sheet was immersed in water heated to 95 ° C. and treated for 10 minutes, and the applied PVA was removed to obtain a sheet-like material.

(Half cut and brushed)
The obtained polymer elastic resin-imparted sheet after removing PVA is cut in half perpendicular to the thickness direction, and the opposite side of the half-cut surface is ground with sandpaper count 240 endless sandpaper to obtain a thickness of 0.7 mm. A sheet-like material having fluffy hair was obtained.

(Staining and finishing)
The obtained sheet-like material having naps was dyed with a black dye using a liquid flow dyeing machine under a temperature condition of 120 ° C. Then, it was dried with a drier to obtain a sheet-like material having an average single fiber fineness of 4.4 μm. Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. In addition, N-acylurea bonds and isourea bonds were present in the polymer elastic bodies, and there were 49 filamentous polymer elastic bodies, and the surface coverage was 72%.

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

(Ultrafine fiber)
It was carried out in the same manner as in Example 1.

(Addition of polymer elastic resin)
The active ingredient of the nonionic thickener (guar gum) is added to the water-dispersed polyurethane dispersion Wa prepared so that the polyurethane solid content concentration is 20% with respect to the solid content 100% by mass of the polymer elastic body a having a hydrophilic group. 1% by mass relative to polyurethane solid content, 30% by mass of sodium sulfate as a heat-sensitive coagulant, 3% by mass of carbodiimide-based cross-linking agent, and the whole is adjusted to 17% by mass with water to have a high solid content having a hydrophilic group. An aqueous dispersion containing the molecular elastic body a was obtained. The heat-sensitive solidification temperature was 65 ° C. The obtained PVA-imparted ultrafine fiber non-woven fabric is 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 to obtain polyurethane with respect to the island component mass of the non-woven fabric. A polymer elastic resin-imparted sheet having a thickness of 2.0 mm and having a mass of 45% by mass was obtained.

From half-cutting to finishing, the same procedure as in Example 1 was carried out to obtain a sheet-like material having an average single fiber fineness of 4.4 μm. Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered, and the length of the surface layer fibers was uniform and had a glossy feeling. In addition, N-acylurea bond and isourea bond were present in the polymer elastic body, and there were 38 filamentous polymer elastic bodies, and the surface coverage was 69%.

[Example 3]
In Example 1 (adding a polymer elastic resin), the aqueous dispersion containing the polymer elastic having a hydrophilic group was changed (specifically, the water of the polymer elastic b having a hydrophilic group). A sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers was obtained in the same manner as in Example 1 except for the dispersion liquid Wb). Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. In addition, N-acylurea bond and isourea bond were present in the polymer elastic body, and there were 44 filamentous polymer elastic bodies, and the surface coverage was 66%.

[Example 4]
In Example 2 (adding a polymer elastic resin), the aqueous dispersion containing the polymer elastic having a hydrophilic group was changed (specifically, the water of the polymer elastic b having a hydrophilic group). A sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers was obtained in the same manner as in Example 2 except for the dispersion liquid Wb). Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. Further, N-acylurea bond and isourea bond were present in the polymer elastic body, and there were 40 filamentous polymer elastic bodies, and the surface coverage was 67%.

[Example 5]
In Example 1 (addition of polymer elastic resin), sodium chloride (Table 1) was used as a heat-sensitive gelling agent with respect to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group. In the same manner as in Example 1, a sheet-like material having an average single fiber fineness of 4.4 μm was prepared in the same manner as in Example 1 except that 25% by mass (described as “NaCl”) was added and the heat-sensitive coagulation temperature was adjusted to 60 ° C. Obtained. Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. In addition, N-acylurea bonds and isourea bonds were present in the polymer elastic body, and there were 46 filamentous polymer elastic bodies, and the surface coverage was 70 [Example 6].
In Example 1 (addition of polymer elastic 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 polymer elastic body a having a hydrophilic group. % Was added to obtain a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers in the same manner as in Example 1 except that the heat-sensitive coagulation temperature was adjusted to 60 ° C. Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. Further, N-acylurea bond and isourea bond were present in the polymer elastic body, 51 filamentous polymer elastic bodies were present, and the surface coverage was 68%.

[Example 7]
In Example 1 (addition of polymer elastic 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 polymer elastic body a having a hydrophilic group. % Was added to obtain a sheet-like product having an average single fiber fineness of 4.4 μm of ultrafine fibers in the same manner as in Example 1 except that the heat-sensitive coagulation temperature was adjusted to 70 ° C. Similar to FIG. 1, the obtained sheet-like material formed a structure in which the fibers and the polymer elastic body were partially adhered to each other, and the length of the surface layer fibers was uniform and had a glossy feeling. In addition, N-acylurea bonds and isourea bonds were present in the polymer elastic body, and there were 33 filamentous polymer elastic bodies, and the surface coverage was 66%.

[Comparative Example 1]
To 100% by mass of the solid content of the polymer elastic body a having a hydrophilic group, 30% by mass of sodium sulfate was added as a heat-sensitive coagulant, 3% by mass of a carbodiimide-based cross-linking agent was added, and the whole was 17% by mass of solid content with water. Was adjusted to%, and an aqueous dispersion containing a polymer elastic body a having a hydrophilic group was obtained. The heat-sensitive solidification temperature was 65 ° C. The obtained PVA-imparted ultrafine fibrous nonwoven fabric was immersed in the aqueous dispersion and then dried with hot air at a temperature of 120 ° C. for 30 minutes to impart 45% by mass of the polymer elastic body A with respect to the fiber weight. , A polymer elastic resin-imparting sheet having a thickness of 1.9 mm was obtained. Although the obtained sheet-like material had a flexible texture, the appearance quality was grade 3. Further, the polymer elastic body had an N-acylurea bond and an isourea bond, and the surface coverage was 67%, but the number of filamentous polymer elastic bodies was 14.

[Comparative Example 2]
When magnesium sulfate was used as the heat-sensitive coagulant in Example 1 (addition of polymer elastic resin) in the same manner as in Example 1, water containing a polymer elastic having a hydrophilic group was used. The dispersion liquid gelled during processing, and it was not possible to obtain a polymer elastic resin-imparting sheet.

[Comparative Example 3]
In Example 1 (adding a polymer elastic resin), magnesium sulfate was used as a heat-sensitive gelling agent with respect to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group. A sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers 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. Although the obtained sheet-like material had a soft texture, impregnation unevenness occurred and the appearance quality was grade 3. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, and the surface coverage was 63%, but the number of filamentous polymer elastic bodies was 17.

[Comparative Example 4]
In Example 1 (adding a polymer elastic resin), sodium sulfate was added as a heat-sensitive gelling agent to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic a having a hydrophilic group. A sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers 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-like material had a hard texture and had a second grade appearance quality. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, but the number of filamentous polymer elastic bodies was 11, and the surface coverage was 55%.

[Comparative Example 5]
In Example 1 (adding a polymer elastic 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 polymer elastic body a having a hydrophilic group. % Was added to obtain a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers in the same manner as in Example 1 except that the heat-sensitive coagulation temperature was adjusted to 60 ° C. Although the obtained sheet-like material had a flexible texture, the appearance quality was grade 3. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, and the surface coverage was 69%, but the number of filamentous polymer elastic bodies was 14.

[Comparative Example 6]
In Example 1 (addition of polymer elastic resin), a cross-linking agent was not added to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group. In the same manner as in Example 1, a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers was obtained. Although the obtained sheet-like material had a flexible texture, the appearance quality was second grade. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, but the number of filamentous polymer elastic bodies was 26 and the surface coverage was 58%.

[Comparative Example 7]
In Example 1 (addition of polymer elastic resin), a thickener was not added to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group. Obtained a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers in the same manner as in Example 1. Although the obtained sheet-like material had a flexible texture, the appearance quality was grade 3. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, but the number of filamentous polymer elastic bodies was eight and the surface coverage was 58%.

[Comparative Example 8]
In Example 1 (addition of polymer elastic resin), 3% by mass of an oxazoline-based cross-linking agent was added to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group. A sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers was obtained in the same manner as in Example 1. Although the obtained sheet-like material had a flexible texture, the appearance quality was grade 3. The number of filamentous polymer elastic bodies was 39, and the surface coverage was 63%, but N-acylurea bonds and isourea bonds could not be confirmed in the polymer elastic bodies.

[Comparative Example 9]
Except that the heat-sensitive coagulant was not added to 100% by mass of the solid content of the aqueous dispersion Wa of the polymer elastic body a having a hydrophilic group in Example 1 (addition of polymer elastic resin). Obtained a sheet-like material having an average single fiber fineness of 4.4 μm of ultrafine fibers in the same manner as in Example 1. The obtained sheet-like material had a hard texture and had a second grade appearance quality. Further, it was confirmed that the polymer elastic body had an N-acylurea bond and an isourea bond, but the number of filamentous polymer elastic bodies was 10, and the surface coverage was 54%.

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

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

1: Polymer elastic body 2: Polymer elastic body 3: Ultrafine fiber 4: Ultrafine fiber 5: Ultrafine fiber 6: Polymer elastic body 7: Extrafine fiber 8: Extrafine fiber 9: Extrafine fiber 10: Floor surface 11: Inspection table 12: Sheet-like object 13: Line connecting the visually confirmed position and the sheet-like object 14: Visually confirmed position 15: Fluorescent lamp 16: Vertical line from the sheet-like object to the fluorescent lamp

Claims (6)

It is a sheet-like material containing a fibrous base material and a polymer elastic body, and 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. Adhesion to ultrafine fibers in a range of 500 μm square including a hydrophilic group and N-acylurea bond and / or isourea bond, and including 500 or more cross-sectional portions of ultrafine fibers in a cross section obtained by cutting a sheet in the thickness direction. A sheet-like material having a length from a portion of 10 μm or more and a maximum width of a portion within 10 μm from the portion bonded to the ultrafine fibers exceeding 0 μm and 5 μm or less in number of 20 or more polymer elastic bodies. .. The sheet-like material according to claim 1, wherein the number of the polymer elastic bodies is 30 or more. The sheet-like material according to claim 1 or 2, which has a napped layer and has a surface coverage of ultrafine fibers in the napped layer of 60% or more and 90% or less. The method for producing a sheet-like product according to any one of claims 1 to 3, wherein the fibrous substrate is impregnated with an aqueous dispersion, and the coagulation treatment is performed with a coagulation solvent having a pH of 1 or more and 3 or less. The fibrous substrate comprises a step of performing a coagulation treatment by an acid coagulation method or a hot water coagulation method of performing a coagulation treatment in hot water of 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 aqueous dispersion is composed of ultrafine fibers having an average single fiber fineness of 0.1 μm or more and 10 μm or less, and the aqueous dispersion has a polymer elastic body having a hydrophilic group, a cross-linking agent, and a polymer elastic body solid content mass 100 having the hydrophilic group. A method for producing a sheet-like substance, which contains a monovalent cation-containing inorganic salt of 10 parts by mass or more and 50 parts by mass or less with respect to a mass portion, and a thickener. The method for producing a sheet-like product according to claim 4, wherein the cross-linking agent is a carbodiimide-based cross-linking agent. The method for producing a sheet-like product according to claim 4 or 5, wherein the thickener is a nonionic thickener.