Patent Description:
Conventionally, leather-like sheets such as artificial leather and synthetic leather have been used for shoes and clothing, and interior materials of vehicles and articles of furniture. Such leather-like sheets are put to uses in which their surfaces come into contact with other objects. In such uses, leather-like sheets are required to have the property of being resistant to wear caused by friction against other objects.

For example, PTL <NUM> listed below discloses a leather-like sheet in which a resin skin layer composed mainly of a non-yellowing polycarbonate-based urethane resin is stacked on a surface of a natural leather base material via an adhesive layer made of a resin composed mainly of a polycarbonate-based urethane resin, wherein the resin skin layer contains <NUM> to <NUM> parts by weight of a spherical fine powder having an average particle size of <NUM> or less, per <NUM> parts by weight of the resin composed mainly of the non-yellowing polycarbonate-based urethane. PTL <NUM> also discloses, as the spherical fine powder, a melamine resin, a phenol resin, and a benzoguanamine resin.

For example, PTL <NUM> listed below discloses a ball skin material including a fiber base material, and a surface resin layer disposed on one surface of the fiber base material, the surface resin layer containing an elastic polymer, inorganic particles, and a protein powder.

PTL <NUM> concerns an artificial leather comprising a fluororesin powder in a film in an amount of <NUM> to <NUM> pbw based on the dried film weight in the film.

PTL <NUM> relates to an aqueous resin composition for a artificial leather which contains a crosslinkable aqueous urethane resin, a crosslinking agent and organic fine particles.

PTL <NUM> describes a polyurethane resin layer laminated through an adhesive to a textile substrate of a woven or a knitted fabric, a nonwoven fabric, etc., composed of natural, regenerated, semisynthetic, synthetic fiber, etc., to form a receiving layer, wherein a resin layer of a silicone-modified polyurethane, prepared by reacting a silicone-modified polyol with an isocyanate, is then formed thereon.

PTL <NUM> discloses a paint composition comprising (A) a fluorine-containing copolymer, (B) a solvent and (C) a resin particle satisfying certain conditions.

PTL <NUM> concerns an aromatic synthetic leather comprising a polyurethane leather layer in which a urethane adhesive layer and a polyurethane skin layer are sequentially laminated, wherein the polyurethane skin layer contains microcapsules containing an aromatic substance.

PTL <NUM> discloses a grain-finished leather-like sheet fulfilling certain parameters and comprising a polyurethane skin film containing a polyether-based polyurethane, wherein the polyurethane skin film contains a quinacridone-based red pigment, the number of cycles of a flexing endurance test at which cracking occurs in a surface of the polyurethane skin film is <NUM> or more.

PTL <NUM> concerns a fiber artificial leather which comprises at least three layers, wherein the inner layer is superfine fiber basic material which is a surface formed after polyurethane resin is dipped and provided with micropores, the middle layer is a polyurethane film which contains polyurethane components and fits in with the inner layer, and the surface layer contains an abrasive-resistant polyurethane film.

PTL <NUM> discloses a certain leather-like sheet comprising a fibrous substrate and a grain-finished portion covering <NUM>% or more of a surface of the fibrous substrate, wherein the grain-finished portion comprises a surface layer and an optional coating layer, and the surface layer comprises non-modified hollow nanosilica particles having a primary particle size of <NUM> to <NUM> and an elastic polymer, or comprises modified hollow nanosilica particles and an optional elastic polymer, and wherein the modified hollow nanosilica particles are particles which are surface-modified with at least one compound selected from the group consisting of a compound having isocyanate group, a compound having alkyl group, a compound having aryl group and a compound having UV-sensitive functional group.

PTL <NUM> relates to a textile article comprising a web of material, a polymeric layer disposed on the web of material, wherein the polymeric layer comprises a polymeric matrix comprising polyurethane, and polymer particles disposed in the polymeric matrix, wherein the polymer particles comprise a different composition from the polymeric matrix.

For example, shoes for use in sports played in gymnasiums are repeatedly rubbed against the floor during games, and the rubbed portions may be melted by frictional heat. Also, sports shoes for use in sports played in gymnasiums are repeatedly subjected to bending by movements of the players. For that reason, for sports shoes for use in sports played in gymnasiums, there has been a need for leather-like sheets with a surface having a combination of high frictional melt resistance, which is the property of being resistant to melting by frictional heat, and high bending resistance.

It is an object of the present invention to provide a leather-like sheet with a surface having a combination of high frictional melt resistance and high bending resistance.

An aspect of the present invention is directed to a leather-like sheet including: a fiber base material; an intermediate resin layer stacked on one surface of the fiber base material; and a surface resin layer stacked on the intermediate resin layer, wherein the surface resin layer contains a polyether-based polyurethane and spherical fine particles having a heat resistance at <NUM>, and a content ratio of the spherical fine particles is <NUM> to <NUM> mass%, and the spherical fine particles has a specific heat capacity of <NUM> kJ/(kg·K) or more, and a particle size D<NUM> (median diameter) at a cumulative distribution of <NUM> vol%, of <NUM> to <NUM>, and a particle size D<NUM> at a cumulative distribution of <NUM> vol% of the spherical fine particles satisfies a condition that a particle size dispersity D<NUM>/D<NUM> ≤ <NUM>. Such a leather-like sheet provides a leather-like sheet with a surface having a combination of high frictional melt resistance and high bending resistance.

Examples of the spherical fine particles include melamine resin-silica composite particles, benzoguanamine resin particles, and polytetrafluoroethylene resin particles.

It is preferable that the surface resin layer has a thickness of <NUM> to <NUM>, from the viewpoint of obtaining a leather-like sheet that offers a good balance between high frictional melt resistance, high bending resistance, and mechanical properties.

It is preferable that the number of cycles of a flexing endurance test at which cracking occurs in the surface resin layer is <NUM> or more, when the flexing endurance test is performed on the leather-like sheet in an environment of <NUM> using a flexometer, from the viewpoint of obtaining a leather-like sheet that offers a particularly good balance between high frictional melt resistance and high bending resistance.

It is preferable that the fiber base material includes a non-woven fabric including ultrafine fibers having a fineness of <NUM> dtex or less, and an elastic polymer impregnated in the non-woven fabric, from the viewpoint of obtaining a leather-like sheet that offers a good balance between high frictional melt resistance, high bending resistance, and mechanical properties.

According to the present invention, it is possible to obtain a leather-like sheet with a surface having a combination of high frictional melt resistance and high bending resistance.

[<FIG> is a schematic cross-sectional view of a leather-like sheet <NUM> according to an embodiment.

Hereinafter, an embodiment of a leather-like sheet according to the present invention will be described in detail with reference to the drawing. <FIG> is a schematic cross-sectional view of a leather-like sheet <NUM> according to the present embodiment.

Referring to <FIG>, the leather-like sheet <NUM> includes a fiber base material <NUM>, an intermediate resin layer <NUM> bonded to one surface of the fiber base material <NUM> via an adhesive layer <NUM>, and a surface resin layer <NUM> stacked on the intermediate resin layer <NUM>. The resin layers, including the adhesive layer <NUM>, the intermediate resin layer <NUM>, and the surface resin layer <NUM>, form a grain-finished resin layer <NUM>. The grain-finished resin layer <NUM> is a layer that imparts an appearance and a tactile impression that resemble those of a grain surface of natural leather to the leather-like sheet <NUM>. The grain-finished resin layer <NUM> may further include another layer such as a topcoat layer as needed.

The surface resin layer <NUM> contains an elastic polymer including a polyether-based polyurethane, and spherical fine particles 4a dispersed in the elastic polymer and having a heat resistance at <NUM>. The spherical fine particles 4a have a specific heat capacity of <NUM> kJ/(kg ·K) or more, and a particle size D<NUM> (median diameter) at a cumulative distribution of <NUM> vol%, of <NUM> to <NUM>, and a particle size D<NUM> at a cumulative distribution of <NUM> vol% of the spherical fine particles 4a satisfies a condition that a particle size dispersity D<NUM>/D<NUM> ≤ <NUM>. By including an elastic polymer including a polyether-based polyurethane and the above-described spherical fine particles having a heat resistance at <NUM> in the surface resin layer <NUM>, a surface having a combination of high frictional melt resistance and high bending resistance is imparted to the leather-like sheet <NUM>.

As the fiber base material, fiber base materials composed mainly of a non-woven fabric, a woven fabric, a knitted fabric or a sheet formed by a combination thereof conventionally used for production of a leather-like sheet, and into which an elastic polymer is further impregnated as needed may be used without any particular limitation. Among these, a fiber base material including a non-woven fabric, in particular, a non-woven fabric into which an elastic polymer has been impregnated and that includes ultrafine fibers having a fineness of <NUM> dtex or less is preferable from the viewpoint of ease of obtaining a leather-like sheet that is dense and has high mechanical strength.

The fibers that form the fiber base material include ultrafine fibers having a fineness of preferably <NUM> dtex or less, and more preferably <NUM> to <NUM> dtex, from the viewpoint of ease of obtaining a leather-like sheet with low fiber density unevenness and high uniformity. Here, the fineness is determined by imaging a cross section of the napped artificial leather that is parallel to the thickness direction thereof using a scanning electron microscope (SEM) at a magnification of 3000X, and calculating an average value of the diameters of <NUM> evenly selected fibers by using the density of the resin that forms the fibers.

The type of the resin that forms the fibers is not particularly limited. Specific examples of the resin that forms the fibers include synthetic fibers including, for example, polyamide resins such as polyamide <NUM>, polyamide <NUM>, polyamide <NUM>, aromatic polyamide, and a polyamide elastomer; polyester resins such as polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and a polyester elastomer; acrylic resins; olefin resins; and polyvinyl alcohol resins, and various natural fibers and semisynthetic fibers. These may be used alone or in a combination of two or more. As the method for producing a synthetic fiber, for example, a melt-spinning method in which a resin is melted at a temperature greater than or equal to the melting point, and is extruded from an extruder, a dry solution spinning method in which a polymer solution is extruded from pores, and a solvent is evaporated, or a wet solution spinning method in which a polymer solution is spun into a non-solvent can be used without any particular limitation. The non-woven fabric of ultrafine fibers is obtained, for example, by subjecting ultrafine fiber-generating fibers such as island-in-the-sea conjugated fibers to entangling treatment, to form a fiber-entangled body, and subjecting the fiber-entangled body to ultrafine fiber-generating treatment.

The fiber base material may contain an elastic polymer impregnated therein. The type of the elastic polymer impregnated in the fiber base material is not particularly limited, and specific examples thereof include various elastic polymers, including, for example, polyurethane; acrylic elastic bodies such as an acrylonitrile-butadiene copolymer and a copolymer of an acrylic acid ester or a methacrylic acid ester; polyamide-based elastic bodies; and silicone rubber. Among these, polyurethane is particularly preferable from the viewpoint of obtaining a good texture. Note that as the soft segment of the polyurethane, one of a polyester unit, a polyether unit, a polycarbonate unit may be included, or a combination thereof may be used. These may be used alone, or in a combination of two or more.

When the fiber base material contains an elastic polymer impregnated therein, the content ratio of the elastic polymer is preferably such that the mass ratio of the fibers forming the fiber base material to the elastic polymer (fibers/elastic polymer) is in the range of preferably <NUM>/<NUM> to <NUM>/<NUM>, and more preferably <NUM>/<NUM> to <NUM>/<NUM>. When the content ratio of the elastic polymer is too high, the resulting leather-like sheet tends to have a rubber-like hard texture.

The thickness of the fiber base material is not particularly limited, but is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>.

Referring to <FIG>, the surface resin layer <NUM> is stacked on one surface of the fiber base material <NUM> of the leather-like sheet <NUM> via the adhesive layer <NUM> and the intermediate resin layer <NUM>. The surface resin layer <NUM> is a layer that imparts a surface having a combination of high frictional melt resistance against repeated rubbing of the surface of the leather-like sheet, and high bending resistance that is less likely to cause cracking or the like even against repeated bending. Such a surface resin layer <NUM> contains the elastic polymer including the polyether-based polyurethane, and the spherical fine particles 4a dispersed in the elastic polymer and having a heat resistance at <NUM>.

The spherical fine particles have a heat resistance at <NUM>, a specific heat capacity of <NUM> kJ/(kg·K) or more, and a particle size D<NUM> (median diameter) at a cumulative distribution of <NUM> vol%, of <NUM> to <NUM>, and a particle size D<NUM> at a cumulative distribution of <NUM> vol% of the spherical fine particles has a particle size distribution in which a particle size dispersity D<NUM>/D<NUM> ≤ <NUM>.

The spherical fine particles having a heat resistance at <NUM> are spherical fine particles that do not melt when heated for <NUM> minutes in a dryer set at <NUM>, as will be described later. When the spherical fine particles do not have a heat resistance at <NUM>, the frictional melt resistance is reduced.

The specific heat capacity of the fine particles that satisfy a specific heat capacity of <NUM> kJ/(kg·K) or more is the specific heat capacity of the spherical fine particles as measured by DSC (differential scanning calorimeter) in accordance with JIS K <NUM>: Testing methods for specific heat capacity of plastics, as will be described later. The specific heat capacity of the spherical fine particles is preferably <NUM> kJ/(kg K) or more, and more preferably <NUM> kJ/(kg·K) or more. When the specific heatcapacity of the spherical fine particles is less than <NUM> kJ/(kg·K), the frictional melt resistance is reduced. When the specific heat capacity is <NUM> kJ/(kg·K) or more, the speed at which the temperature of the surface resin layer in which the spherical fine particles are included is increased due to frictional heat is suppressed.

Specific examples of the spherical fine particles having a heat resistance at <NUM>, and a specific heat capacity of <NUM> kJ/(kg·K) or more include melamine resin-silica composite particles, benzoguanamine resin particles, and polytetrafluoroethylene (PTFE) resin particles. These particles are preferably crosslinked spherical resin fine particles. Note that the term "spherical" does not necessarily mean to be true spheres, but means not to be at least particles produced by crushing, such as flaky particles. Among these, melamine resin-silica composite particles are particularly preferable in that, due to the presence of silica in the particles surface, the particles are less likely to be fused to each other even at a temperature exceeding <NUM>.

Also, the spherical fine particles have a particle size D<NUM> (median diameter) at a cumulative distribution of <NUM> vol%, of <NUM> to <NUM>, and a particle size D<NUM> at a cumulative distribution of <NUM> vol% of the spherical fine particles satisfies a condition that a particle size dispersity D<NUM>/D<NUM> ≤ <NUM>. When the spherical fine particles having a heat resistance at <NUM> and a specific heat capacity of <NUM> kJ/(kg·K) or more have such a particle size and a particle size dispersity that is sharply controlled, the frictional melt resistance is improved.

The particle size D<NUM> (median diameter) of the spherical fine particles is <NUM> to <NUM>. When the particle size D<NUM> exceeds <NUM>, the surface of the surface resin layer is roughened, so that the abrasion resistance is likely to be reduced, or coarse particles become visible, so that the quality of the appearance is likely to be reduced. When a surface resin layer is formed by coating, linear irregularities are likely to be formed on the surface. When the particle size D<NUM> is smaller than <NUM>, the ratio of minute particles, which contribute less to the improvement of the frictional melt resistance, is increased, so that it is difficult to achieve a sufficient effect.

The spherical fine particles are fine particles that are controlled to have a sharp particle size distribution so as to satisfy a condition that the particle size dispersity D<NUM>/D<NUM> ≤ <NUM>. When the particle size dispersity of the spherical fine particles is D<NUM>/D<NUM>><NUM>, the ratio of the fine particles having a particle size of D<NUM> or less becomes relatively high. The fine particles having a particle size of D<NUM> or less contribute less to the improvement of the frictional melt resistance. Therefore, in order to achieve high frictional melt resistance, the mixing ratio of the spherical fine particles needs to be increased. In that case, the bending resistance is likely to be reduced.

The surface resin layer contains an elastic polymer including a polyether-based polyurethane.

The polyether-based polyurethane can be obtained by reacting a urethane raw material containing a polymer polyol including a polyether-based polyol, an organic polyisocyanate, and a chain extender.

Specific examples of the polyether-based polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and poly(methyl tetramethylene glycol).

Specific examples of the organic polyisocyanate include hardly yellowing diisocyanates, including, for example, aromatic diisocyanates such as <NUM>,<NUM>-tolylene diisocyanate, <NUM>,<NUM>-tolylene diisocyanate, <NUM>,<NUM>'-diphenylmethane diisocyanate, and xylylene diisocyanate polyurethane; and non-yellowing diisocyanates, including, for example, aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and <NUM>,<NUM>'-dicyclohexyl methane diisocyanate.

Specific examples of the chain extender include diamines such as hydrazine, ethylene diamine, propylene diamine, hexamethylene diamine, nonamethylene diamine, xylylene diamine, isophorone diamine, piperazine and derivatives thereof, adipic acid dihydrazide, and isophthalic acid dihydrazide; triamines such as diethylenetriamine; tetramines such as triethylene tetramine; diols such as ethylene glycol, propylene glycol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-hexanediol, <NUM>,<NUM>-bis(β-hydroxyethoxy)benzene, and <NUM>,<NUM>-cyclohexanediol; triols such as trimethylol propane; pentaols; pentaerythritol; and amino alcohols such as amino ethyl alcohol and amino propyl alcohol.

The ratio of the polyether-based polyurethane included in the elastic polymer contained in the surface resin layer is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and particularly preferably <NUM> to <NUM> mass%, from the viewpoint of ease of maintaining a particularly high bending resistance. Examples of the elastic polymer other than the polyether-based polyurethane included in the elastic polymer include various elastic polymers including, for example, polyurethane other than a polyether-based polyurethane, such as a polyester-based polyurethane and a polycarbonate-based polyurethane, acrylic elastic bodies such as an acrylonitrile-butadiene copolymer, or a copolymer of an acrylic acid ester or a methacrylic acid ester, polyamide-based elastic bodies, and silicone rubber. The ratio of the polyether-based polyurethane contained in the surface resin layer is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and particularly preferably <NUM> mass% or more.

The content ratio of the spherical fine particles contained in the surface resin layer is <NUM> to <NUM> mass%. When the content ratio of the spherical fine particles in the surface resin layer is less than <NUM> mass%, the frictional melt resistance is not sufficiently improved. When the content ratio of the spherical fine particles in the surface resin layer exceeds <NUM> mass%, the bending resistance is likely to be reduced.

The surface resin layer may contain, as needed, various additives or the like such as an antioxidant, an ultraviolet absorber, a pigment, a dye, a surfactant, an antistatic agent, a flame retardant, an anti-tacking agent, a filler, and a crosslinking agent, as long as the effects of the present invention are not impaired.

The thickness of the surface resin layer is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>, from the viewpoint of ease of obtaining a leather-like sheet with a surface having a combination of high frictional melt resistance, high bending resistance, and a natural leather-like flexible texture.

Referring to <FIG>, the surface resin layer <NUM> is stacked on the fiber base material <NUM> via the adhesive layer <NUM> and the intermediate resin layer <NUM>. The leather-like sheet according to the present embodiment can be produced, for example, by a method involving forming a surface resin layer on release paper, further forming an intermediate resin layer on the surface of the surface resin layer, further forming an adhesive layer on the surface of the intermediate resin layer, bonding the adhesive layer formed on the release paper to the surface of the fiber base material by pressure bonding, and subsequently releasing the release paper.

The intermediate resin layer is a layer composed mainly of an elastic polymer, and contains, as needed, various additives or the like such as an antioxidant, an ultraviolet absorber, a pigment, a dye, a surfactant, an antistatic agent, a flame retardant, an anti-tacking agent, a filler, and a crosslinking agent. The type of the elastic polymer forming the intermediate resin layer is not particularly limited, and examples thereof include various elastic polymers including, for example, polyurethane; acrylic elastic bodies such as an acrylonitrile-butadiene copolymer and a copolymer of an acrylic acid ester or a methacrylic acid ester; polyamide-based elastic bodies; and silicone rubber. Among these, polyurethane is preferable from the viewpoint of obtaining a good texture, and in particular, a polyether-based polyurethane is preferable from the viewpoint of ease of increasing the bending resistance.

The thickness of the intermediate resin layer is not particularly limited, but is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>, from the viewpoint of ease of obtaining a leather-like sheet that offers a good balance between mechanical properties and the texture or the like.

The adhesive layer is also a layer composed mainly of an elastic polymer, and contains, as needed, various additives or the like such as an antioxidant, an ultraviolet absorber, a pigment, a dye, a surfactant, an antistatic agent, a flame retardant, an anti-tacking agent, a filler, and a crosslinking agent. The type of the elastic polymer forming the adhesive layer is also not particularly limited, and any adhesive that includes the same various elastic polymers as those described above, and that is composed mainly of an elastic polymer having a high adhesion strength to the fiber base material can be used without any particular limitation. As the elastic polymer serving as the main component of the adhesive layer, polyurethane is preferable from the viewpoint of obtaining a good texture, and in particular, a polyether-based polyurethane is preferable from the viewpoint of ease of increasing the bending resistance.

The thickness of the adhesive layer is not particularly limited, but is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>, from the viewpoint of ease of obtaining a leather-like sheet that offers a good balance between the mechanical properties and the texture or the like.

The leather-like sheet according to the present embodiment described above has a combination of high frictional melt resistance and high bending resistance. In particular, a leather-like sheet can be obtained in which the number of cycles of a flexing endurance test at which cracking occurs in the surface resin layer is preferably <NUM> or more, and more preferably <NUM> or more, when the flexing endurance test is performed on the leather-like sheet in an environment of <NUM> using a flexometer.

Next, the present invention will be described in further detail by way of examples; however, the scope of the present invention is by no means limited by the following examples. First, the evaluation methods used in the present examples will be collectively described below.

Into a tray made of aluminum foil, <NUM> to <NUM> of powder of the spherical fine particles used in each of the examples was weighed, and the tray was heated for <NUM> minutes in an electric heating dryer at <NUM>. Then, after cooling the spherical fine particles, spherical fine particles that maintained the powder state, or spherical fine particles that were lightly fixed, but were loosened and returned to the powder state when a light force was applied thereto with a medicine spoon or the like were evaluated as A (with heat resistance at <NUM>). Spherical fine particles that melted to form a film, or spherical fine particles that were completely fused with each other, and did not return to the power state were evaluated as B (without heat resistance at <NUM>).

The cumulative particle size distribution of the spherical fine particles used in each of the examples was measured by a dry method using a laser diffraction/scattering analyzer LA-950V2 (HORIBA, Ltd. Then, from the measured cumulative particle size distribution, the particle size dispersity D<NUM>/D<NUM> was determined, where D<NUM> was the particle size at a cumulative distribution of <NUM> vol% and D<NUM> was the particle size at a cumulative distribution of <NUM> vol%.

The specific heat capacity (kJ/(kg·K)) of the spherical fine particles used in each of the examples was measured using a differential scanning calorimeter DSC <NUM> (PerkinElmer Co. ), in accordance with JIS K <NUM>: Testing methods for specific heat capacity of plastics.

A strip-shaped test piece (<NUM> × <NUM>) was cut out from the leather-like sheet obtained in each of the examples. Then, a roller made or cherry tree (diameter: <NUM>, width: <NUM>) rotating at <NUM> rpm was brought into contact under a load of <NUM> lb (<NUM>) with the surface of the strip-shaped test piece on which the surface resin layer was formed. Then, the time from when the surface resin layer had melted until when the fiber base material was exposed was measured at intervals of <NUM> second (rounded off), up to a maximum of <NUM> seconds.

The leather-like sheets obtained in each of the example was subjected to a bending resistance test in an environment of a relative humidity of <NUM>±<NUM>% and a temperature of <NUM>±<NUM>, using a flexometer compliant with JIS K <NUM>. Specifically, the presence or absence of the occurrence of cracking in the surface of the leather-like sheet on which the surface resin layer was formed was checked for every <NUM> flexing cycles performed by the flexometer. Cracking was visually checked using a 30X magnifier. Then, the number of cycles was determined as "Less than <NUM> cycles " when cracking was confirmed at <NUM> cycles, and as "<NUM> cycles " when cracking was confirmed at <NUM> cycles. For the rest of the test, the determination was made in the same manner for every "<NUM> cycles". Note that each cycle was performed using three samples (N=<NUM>). Then, it was determined that cracking occurred when cracking occurred in one of the samples.

A water-soluble thermoplastic polyvinyl alcohol was used as a sea component, and a PET having an isophthalic acid degree of modification of <NUM> mol% was used as an island component. Using a multicomponent fiber spinning spinneret, filaments of island-in-the-sea conjugated fibers were ejected from the spinneret at <NUM> such that the number of islands per one fiber was <NUM>, and the sea component /island component was <NUM>/<NUM> (mass ratio). Then, the ejector pressure was adjusted such that the spinning rate was <NUM>/min, and the island-in-the-sea conjugated fibers having an average fineness of <NUM> dtex were collected on a net, to obtain a filament web having a basis weight of <NUM>/m<NUM>.

Then, the web was laid in <NUM> layers through cross lapping, and an oil for preventing the needle from breaking was sprayed thereto. Then, the layers of the web were needle punched with <NUM>-barb needles at a punching density of <NUM> punch/cm<NUM>, to obtain an entangled web.

Then, the entangled web was heat-shrunk using steam. Specifically, first, water was added to the entangled web in an amount of <NUM> mass% relative to the mass of the sea component, then the entangled web was heat-treated for <NUM> seconds under a heated steam atmosphere of a relative humidity of <NUM>% and a temperature of <NUM>. The area shrinkage at this time was <NUM>%.

Next, the heat-shrunk web was impregnated with a dispersion of an anionic self-emulsified, aqueous polyurethane (<NUM>% modulus: <NUM> MPa). The concentration of the dispersion of the aqueous polyurethane was such that the mass ratio of the aqueous polyurethan amount/island component amount was <NUM>/<NUM>. Then, the dispersion of the aqueous polyurethane was subjected to gelation treatment under a steam atmosphere in order to prevent migration, and was subsequently dried for <NUM> minutes at <NUM>.

Then, the web into which the aqueous polyurethane had been impregnated was immersed in hot water at <NUM> for <NUM> minutes, thereby removing the sea component to form ultrafine fibers. Then, the ultrafine fibers were dried for <NUM> minutes at a temperature of <NUM>, thus obtaining a fiber base material including a non-woven fabric of ultrafine fibers with <NUM> dtex and having a thickness of <NUM>. Then, the fiber base material having a thickness of <NUM> was sliced on a plane substantially parallel to the surface of the fiber base material, thus obtaining a fiber base material including a non-woven fabric of ultrafine fibers with <NUM> dtex and having a thickness of <NUM> and a basis weight of <NUM>/m<NUM>.

Then, onto release paper having a pattern resembling skin pores, a coating liquid for forming a surface resin layer in which <NUM> parts by mass of a polyether-based polyurethane (PEt-based PU, RESAMINE ME-<NUM> (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ), <NUM> parts by mass of melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ), <NUM> parts by mass of DMF, <NUM> parts by mass of MEK, and <NUM> parts by mass of a black pigment dispersion (DUT-<NUM> (pigment content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) were blended was coated in a wet coating amount of <NUM>/m<NUM> using a roll coater, and was dried. Thus, a surface resin layer was formed. The formed surface resin layer contained <NUM> mass% of the melamine resin-silica composite particles.

Next, onto the surface of the surface resin layer, a coating liquid for forming an intermediate resin layer in which <NUM> parts by mass of a polyether-based polyurethane (RESAMINE ME-<NUM> (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ), <NUM> parts by mass of DMF, <NUM> parts by mass of methyl ethyl ketone, and <NUM> parts by mass of a black pigment dispersion (DUT-<NUM> (pigment content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) were blended was coated in a wet coating amount of <NUM>/m<NUM> using a roll coater, and was dried. Thus, an intermediate resin layer was formed.

Then, onto the surface of the intermediate resin layer, a coating liquid for forming an adhesive layer in which <NUM> parts by mass of a polyether-based polyurethane (RESAMINE UD-8310NTT (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ), <NUM> parts by mass of an isocyanate crosslinking agent (NE crosslinking agent manufactured by Dainichiseika Color & Chemicals Mfg. ), <NUM> parts by mass of a crosslinking accelerator (UD-<NUM> manufactured by Dainichiseika Color & Chemicals Mfg. ), <NUM> parts by mass of DMF, and <NUM> parts by mass of MEK were blended was coated in a wet coating amount <NUM>/m<NUM> using a roll coater, and subsequently was dried for <NUM> minutes at <NUM>. The adhesive layer in a semi-dried state was attached to the surface of the fiber base material, and was further dried for <NUM> minutes at <NUM>. Thereafter, in order to accelerate the crosslinking reaction of the adhesive layer, the whole was heated for <NUM> hours in a dryer at an atmospheric temperature of <NUM>. Then, the release paper was stripped off to expose the surface resin layer.

Thus, a leather-like sheet having a thickness of about <NUM> was obtained. A cross section of the obtained leather-like sheet was observed with a scanning electron microscope (300X). The film thicknesses of randomly selected <NUM> portions were measured, and the average value of the measured values was obtained. The thickness of the surface resin layer was <NUM>, the thickness of the intermediate resin layer was <NUM>, and the thickness of the adhesive layer was <NUM>.

Then, the properties of the obtained leather-like sheet were evaluated by the above-described evaluation methods.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that benzoguanamine resin particles (EPOSTAR M05 manufactured by NIPPON SHOKUBAI CO. ) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that <NUM> mass% of the melamine resin-silica composite particles were included in the surface resin layer instead of including <NUM> mass% of the melamine resin-silica composite particles in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that PTFE particles (Microdispers-<NUM> manufactured by Polysciences) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that the film thickness of the surface resin layer was changed from <NUM> to <NUM> in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) were not blended in the surface resin layer in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that melamine resin particles (PERGOPAK M4 manufactured by Huber Engineered Materials) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that polymethyl methacrylate (PMMA) resin particles (TAFTIC AR650SX manufactured by Japan Exlan Co. ) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that aluminum flakes (TS-408PM manufactured by Toyo Aluminium K. ) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that <NUM> parts by mass of a polycarbonate-based polyurethane (PC-based PU, RESAMINE ME-8210NS (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) was blended as the elastic polymer blended in the surface resin layer in place of <NUM> parts by mass of the polyether-based polyurethane (RESAMINE ME-<NUM> (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that <NUM> parts by mass of a polycarbonate-based polyurethane (RESAMINE ME-8210NS (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) was blended as the elastic polymer blended in the surface resin layer in place of <NUM> parts by mass of the polyether-based polyurethane (RESAMINE ME-<NUM> (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ), and <NUM> mass% of benzoguanamine resin particles (EPOSTAR MS manufactured by NIPPON SHOKUBAI CO. ) were included instead of including <NUM> mass% of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that <NUM> parts by mass of a polycarbonate-based polyurethane (RESAMINE ME-8210NS (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ) was blended as the elastic polymer blended in the surface resin layer in place of <NUM> parts by mass of the polyether-based polyurethane (RESAMINE ME-<NUM> (solid content: <NUM> mass%) manufactured by Dainichiseika Color & Chemicals Mfg. ), and <NUM> mass% of melamine resin particles (EPOSTAR S12 manufactured by NIPPON SHOKUBAI CO. ) were included instead of including <NUM> mass% of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) in Example <NUM>. The results are shown in Table <NUM>.

A leather-like sheet was produced and evaluated in the same manner as in Example <NUM> except that melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd. ) were blended in the surface resin layer in place of the melamine resin-silica composite particles (OPTBEADS <NUM> manufactured by Nissan Chemicals Industries, Ltd) in Example <NUM>. The results are shown in Table <NUM>.

Claim 1:
A leather-like sheet comprising:
a fiber base material;
an intermediate resin layer stacked on one surface of the fiber base material; and
a surface resin layer stacked on the intermediate resin layer,
wherein the surface resin layer comprises a polyether-based polyurethane and
spherical fine particles having a heat resistance at <NUM>, and a content ratio of the spherical fine particles is <NUM> to <NUM> mass%, and
the spherical fine particles have a specific heat capacity, measured in accordance with JIS K <NUM>: Testing methods for specific heat capacity of plastics, of <NUM> kJ/(kg·K) or more, and a particle size D<NUM> (median diameter) at a cumulative distribution of <NUM> vol%, of <NUM> to <NUM>, and a particle size D<NUM> at a cumulative distribution of <NUM> vol% of the spherical fine particles satisfies a condition that a particle size dispersity D<NUM>/D<NUM> ≤ <NUM>,
wherein the heat resistance and particle size D<NUM> and D<NUM> are measured as set out in the description.