CN115917076A

CN115917076A - Artificial leather

Info

Publication number: CN115917076A
Application number: CN202180043399.XA
Authority: CN
Inventors: 上野胜; 橘惣之助; 田口法大
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2020-08-28
Filing date: 2021-08-19
Publication date: 2023-04-04
Also published as: KR20230056624A; EP4206398A1; US20230287625A1; TW202208721A; JPWO2022044945A1; WO2022044945A1

Abstract

The present invention addresses the problem of providing artificial leather having a full thickness, soft softness, and a moderate springback feeling, and is based on artificial leather that contains, as structural elements, a nonwoven fabric comprising microfine fibers having an average single fiber diameter of 0.1 to 10 μm, and a polymeric elastomer, and that satisfies the following formulae (a) and (b). 0.5 ≦ F _A /F _B ＜1···(a)0.5≦F _C /F _B < 1. Cndot. (b) Here, F _A 、F _B 、F _C The densities (g/cm) of the fibers in the layer on one surface side of the artificial leather divided into three equal parts in the thickness direction ³ ) The density (g/cm) of the fibers in the layer at the center in the thickness direction ³ ) Density of fibers in layer on the other surface sideDegree (g/cm) ³ )。

Description

Artificial leather

Technical Field

The present invention relates to a leather-like artificial leather including a nonwoven fabric made of ultrafine fibers and a polymer elastomer, and more particularly, to an artificial leather having a thickness similar to the thickness of a natural leather-like solid feeling, and having soft softness and a moderate springback feeling.

Background

Artificial leathers mainly comprising ultrafine fibers and a polymeric elastomer have excellent characteristics in comparison with natural leathers, such as high durability and uniformity of quality, and are used not only as materials for clothes but also in various fields such as vehicle interior materials, shoes, and miscellaneous goods.

Under such circumstances, in order to cope with various applications, various thicknesses, and hand, physical properties, and surface feeling corresponding thereto are required. Various proposals have been made to meet such a demand (see patent documents 1 to 4).

Documents of the prior art

Patent document

Patent document 1: international publication No. 2015/037528

Patent document 2: japanese patent laid-open No. 2004-91960

Patent document 3: international publication No. 2011/121940

Patent document 4: international publication No. 2017/022387

Disclosure of Invention

Problems to be solved by the invention

As in the technique disclosed in patent document 1 or patent document 2, when a suede-like artificial leather is made to have a specific density structure or is divided into pieces to be made thin, a certain texture or physical properties can be achieved. However, when the thickness is set to a thickness suitable for various products, the texture and physical properties are not sufficient.

In patent document 3, although a certain degree of fullness and softness can be achieved by setting the density in the thickness direction to a specific ratio, the moderate degree of springback feeling that is present in the soft softness of natural leather is not sufficient.

Further, in patent document 4, the touch and the nap feeling of the ground leather (nubuck leather) can be achieved to some extent, but the feeling of having not only the surface feeling but also the soft touch and the springback feeling is not sufficient.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an artificial leather having a thickness with a full feeling, soft softness, and a moderate feeling of springback.

Means for solving the problems

The present inventors have made extensive studies to achieve the above object, and as a result, have obtained the following findings: in the artificial leather, the density of each layer obtained by dividing a specific artificial leather into three equal parts in the thickness direction is reduced, and the density of the fibers in the layer on one surface side and the layer on the other surface side is increased, whereby not only can soft flexibility be provided, but also the occurrence of wrinkles or sagging at the time of bending of the sheet can be suppressed, and the artificial leather has a moderate resilient feeling.

The present invention has been completed based on these findings, and the present invention provides the following inventions.

The artificial leather of the present invention comprises a nonwoven fabric comprising microfine fibers having an average single fiber diameter of 0.1 to 10 μm and a polymeric elastomer as structural elements, and satisfies the following formulae (a) and (b).

0.5≦F _A /F _B ＜1 ···(a)

0.5≦F _C /F _B ＜1 ···(b)

Here, F _A 、F _B 、F _C The densities (g/cm) of the fibers in the layer on one surface side of the artificial leather divided into three equal parts in the thickness direction ³ ) The density (g/cm) of the fibers in the layer at the center in the thickness direction ³ ) The density (g/cm) of the fibers in the layer on the other surface side ³ )。

According to a preferred embodiment of the artificial leather of the present invention, the artificial leather has at least one raised layer formed by raising.

According to a preferred embodiment of the artificial leather of the present invention, the artificial leather further comprises at least one resin layer.

According to a preferred embodiment of the artificial leather of the present invention, the resin layer is formed intermittently in the surface of the artificial leather.

According to a preferred embodiment of the artificial leather of the present invention, the artificial leather further satisfies the following formulae (c) and (d).

0.6≦P _A /P _B ＜1 ···(c)

0.6≦P _C /P _B ＜1 ···(d)

Here, P _A 、P _B 、P _C The densities (g/cm) of the elastic polymer in the layer on one surface side of the artificial leather divided into three equal parts in the thickness direction ³ ) Density (g/cm) of the elastic polymer in the layer at the center in the thickness direction ³ ) And the density (g/cm) of the elastic polymer in the layer on the other surface side ³ )。

According to a preferred embodiment of the artificial leather of the present invention, the artificial leather has a density of 0.2g/cm as a whole ³ Above and 0.7g/cm ³ The following.

According to a preferred embodiment of the artificial leather of the present invention, the artificial leather has a thickness of 0.8mm or more and 4.0mm or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an artificial leather having a thickness with a full feeling, soft softness, and a moderate feeling of springback can be obtained. In particular, the artificial leather of the present invention has a specific density in the thickness direction, and therefore can suppress the occurrence of wrinkles or sagging when the artificial leather is bent, and therefore, the artificial leather can be used in various fields such as clothes, vehicle interior materials, furniture interior materials, building materials, shoes, bags, sundries, and particularly, can be preferably used in shoes, bags, and sundry goods applications requiring a natural leather-like appearance and texture.

Drawings

FIG. 1 is a schematic cross-sectional view schematically illustrating an embodiment of a cross-section of an artificial leather of the present invention.

Fig. 2 is a schematic plan view illustrating a surface morphology of an embodiment of the artificial leather of the present invention.

FIG. 3 is a schematic sectional view schematically illustrating another embodiment of the artificial leather according to the present invention.

Detailed Description

0.5≦F _A /F _B ＜1 ···(a)

0.5≦F _C /F _B ＜1 ···(b)

Here, F _A 、F _B 、F _C The densities (g/cm) of the fibers in the layer on one surface side of the artificial leather divided into three equal parts in the thickness direction ³ ) Density (g/cm) of fibers in the layer at the center in the thickness direction ³ ) The density (g/cm) of the fibers in the layer on the other surface side ³ )。

The present invention is not limited to the following description unless otherwise specified.

[ non-woven fabrics ]

The artificial leather of the present invention comprises, as a structural element, a nonwoven fabric comprising microfine fibers having an average single fiber diameter of 0.1 to 10 μm.

As the microfine fibers of the nonwoven fabric constituting the artificial leather of the present invention, synthetic fibers can be preferably used in order to obtain an artificial leather excellent in mechanical strength, heat resistance and light resistance. Examples of the synthetic fibers include various synthetic fibers including polyesters such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene 2, 6-naphthalene dicarboxylate and polylactic acid, polyamides such as polyamide 6 and polyamide 66, acrylic acid, polyethylene, polypropylene and thermoplastic cellulose. Among the synthetic fibers, polyester fibers or polyamide fibers can be preferably used in particular. Among them, polyester fibers including polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and the like can be particularly preferably used from the viewpoint of excellent strength, dimensional stability, light resistance, and dyeability. Further, in the case of using synthetic fibers as the fibers constituting the nonwoven fabric, fibers containing components derived from renewable raw materials or biomass resources may also be used from the viewpoint of environmental considerations. Further, the ultrafine fibers of different materials may be mixed.

When polyester fibers are used as the synthetic fibers as the biomass resource-derived component, the biomass resource-derived component may be used as a dicarboxylic acid and/or an ester-forming derivative thereof as a raw material of the polyester. In addition, a component derived from biomass resources may be used as the diol. From the viewpoint of reducing the environmental load, it is preferable to use a component derived from a biomass resource in both the dicarboxylic acid and/or the ester-forming derivative thereof and the diol.

In the case of using polyester as the synthetic fiber, as dicarboxylic acid usable as the raw material, there can be mentioned: examples of the aromatic dicarboxylic acid salt include aromatic dicarboxylic acids such as "terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (e.g., 2, 6-naphthalenedicarboxylic acid) and diphenyldicarboxylic acid (e.g., diphenyl-4, 4' -dicarboxylic acid)", aliphatic dicarboxylic acids such as "oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid", alicyclic dicarboxylic acids such as 1, 4-cyclohexanedicarboxylic acid, and aromatic dicarboxylic acid salts such as "5-sulfoisophthalate (e.g., lithium salt of 5-sulfoisophthalate, potassium salt of 5-sulfoisophthalate, sodium salt of 5-sulfoisophthalate)".

Examples of the ester-forming derivative of a dicarboxylic acid to be used as a raw material of the polyester include lower alkyl esters, acid anhydrides, and acid chlorides of dicarboxylic acids. Specifically, methyl ester, ethyl ester, hydroxyethyl ester, and the like can be preferably used.

In addition, as the diol, there may be mentioned: ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, cyclohexanedimethanol, diethylene glycol, 2-methyl-1, 3-propanediol, polyoxyalkylene glycol having a molecular weight of 500 to 20000 (for example, polyethylene glycol), and bisphenol A-ethylene oxide adduct.

When polyamide fibers are used as the synthetic fibers, polyamide 6, polyamide 66, polyamide 56, polyamide 610, polyamide 11, polyamide 12, copolymerized polyamide, or the like can be used. Among them, polyamide 56, polyamide 610, and polyamide 11, which easily contain components derived from biomass resources, can be preferably used.

When synthetic fibers are used as the fibers constituting the nonwoven fabric, inorganic particles such as titanium oxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, antibacterial agents, and the like may be added to the polymer forming the fibers according to various purposes.

The average single fiber diameter of the ultrafine fibers is 0.1 to 10 μm. By setting the average single fiber diameter to 10.0 μm or less, preferably 7.0 μm or less, and more preferably 4.0 μm or less, artificial leather having a dense and soft touch and an excellent surface quality can be obtained. On the other hand, by setting the average single fiber diameter to 0.1 μm or more, preferably 1.0 μm or more, and more preferably 1.5 μm or more, the effect of excellent color developability and fastness after dyeing is exerted.

In the present invention, the average single fiber diameter is calculated by taking a Scanning Electron Microscope (SEM) photograph of the cross section of the artificial leather, randomly selecting 50 circular or nearly circular ultrafine fibers, measuring the single fiber diameter, calculating the arithmetic average of 50, and rounding the second place below the decimal point expressed in μm. When the ultrafine fibers have a deformed cross section, the diameter of each single fiber is determined by measuring the cross-sectional area of each single fiber and calculating the equivalent circle diameter.

The shape of the cross section of the ultrafine fibers may be a circular cross section, but may be a polygonal shape such as an ellipse, a flat shape, or a triangle, or a special-shaped cross section such as a fan shape or a cross shape.

As the nonwoven fabric used in the present invention, either a long fiber nonwoven fabric or a short fiber nonwoven fabric can be used, but a short fiber nonwoven fabric is a preferred form in terms of a large number of raised fibers on the product surface and easy achievement of a beautiful appearance.

The fiber length of the ultrafine fibers in the case of using the short fiber nonwoven fabric is preferably 25mm or more and 90mm or less. By setting the fiber length to 90mm or less, the grade and hand are good, and by setting the fiber length to 25mm or more, artificial leather having excellent abrasion resistance can be produced. The fiber length is more preferably 35mm or more and 80mm or less, and still more preferably 40mm or more and 70mm or less.

The weight per unit area of the nonwoven fabric used in the present invention is preferably 50g/m ² Above and 1000g/m ² The following. The basis weight of the nonwoven fabric was 50g/m ² More preferably 80g/m or more ² As described above, the artificial leather is not easily formed into a paper-like artificial leather, and an artificial leather having excellent hand feeling can be obtained. On the other hand, when the weight per unit area of the nonwoven fabric is set to 1000g/m ² Hereinafter, more preferably 900g/m ² Hereinafter, the hand of the artificial leather is not easily hardened, and the artificial leather is soft.

The weight per unit area of the nonwoven fabric is based on Japanese Industrial Standard (JIS) L1913:2010 "mass per unit area of 6.2" of general nonwoven test method ".

The nonwoven fabric used in the present invention may be integrated by stacking a woven fabric inside or on one side of the nonwoven fabric and interlacing the stacked woven fabric for the purpose of improving the strength and the form stability.

As the kind of fibers constituting the woven fabric used when the woven fabric is entangled and integrated, a filament yarn, a spun yarn-mixed composite yarn, or the like can be used. The spun yarn has a large amount of pile on its structural surface, and when a nonwoven fabric is entangled with a woven fabric, the pile is easily broken off and exposed to the surface, which is a drawback. Therefore, it is more preferable to use filaments, and as the filaments, it is preferable to use multifilaments.

The average filament diameter of the fibers constituting the woven fabric is preferably 1 μm or more and 50 μm or less. An artificial leather having excellent flexibility can be obtained by setting the average single fiber diameter of the fibers constituting the woven fabric to 50 μm or less, and the form stability of a product as an artificial leather is improved by setting the average single fiber diameter to 1 μm or more.

The average single fiber diameter of the fibers constituting the woven fabric used in the present invention is the same as the method for measuring the average single fiber diameter of the ultrafine fibers.

The total fineness of the filaments constituting the fabric was based on JIS L1013: the "8.3.1 positive fineness B) according to the" chemical fiber filament yarn test method "2010 (simple method)" is preferably 30dtex or more and 170dtex or less. An artificial leather having excellent flexibility can be obtained by setting the total fineness to 170dtex or less, and the form stability of a product as an artificial leather is improved by setting the total fineness to 30dtex or more. The total fineness of the multifilament yarn of the warp and the weft is preferably the same as each other.

The fiber constituting the fabric is preferably the same as the structural component of the nonwoven fabric, and preferably contains a component derived from a biomass resource from the viewpoint of reducing environmental load.

In particular, in the nonwoven fabric of artificial leather, the ultrafine fibers constituting the same, or the woven fabric of the present invention, the biomass plasticity specified in International Organization for Standardization (ISO) 16620 (2015) is preferably 5% or more and 100% or less. Further, the biomass plasticity of the nonwoven fabric is more preferably 15% or more, and even more preferably 25% or more, in order to further reduce the environmental load, or to improve the fiber strength of the microfine fibers in the artificial leather and the abrasion resistance of the artificial leather.

In the case where the woven fabric is layered inside or on one side of the nonwoven fabric and intertwined to be integrated as described above, the degree of bioplasticity of the nonwoven fabric and the woven fabric integrated is defined as "degree of bioplasticity of the nonwoven fabric".

In the present invention, the biomass plasticity of the nonwoven fabric and the artificial leather is measured as follows.

(1) The biobased carbon content in the total carbon constituting the components of the sample was measured based on ISO 16620-2.

(2) The components and component ratios constituting the sample were identified.

In addition, known methods such as Gas Chromatography-Mass Spectrometry (GC-MS), nuclear Magnetic Resonance (NMR), elemental analysis, and the like can be used for identification.

(3) And (3) determining the components of the biomass resource source according to the results of (1) and (2).

(4) Of the sample components, the ratio (mass ratio) of components derived from biomass resources was calculated as the degree of biomass plasticity of the sample.

When the bioplastic degree of the nonwoven fabric is measured from the artificial leather, a method of extracting and separating the components of the nonwoven fabric with a solvent in which only the nonwoven fabric is soluble, or conversely a method of removing the components from the artificial leather with a solvent in which the polymer elastomer and the resin layer are soluble, or the like can be suitably employed depending on the structural components of the artificial leather.

As a method for removing components other than the nonwoven fabric from the artificial leather, for example, a method of extracting components including the polymer elastomer or the resin layer using N, N-dimethylformamide heated to 60 ℃ or higher and 100 ℃ or lower can be used.

[ Polymer elastomer ]

Further, the artificial leather of the present invention comprises the nonwoven fabric and the polymer elastomer as constituent elements.

The polymer elastomer used in the present invention mainly functions as a binder for holding the nonwoven fabric, which is a structural element of the artificial leather. In order to obtain artificial leather having a soft touch, polyurethane, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), acrylic resin, and the like can be used as the polymer elastomer. Among them, polyurethane is preferably used as a main component. By using polyurethane, artificial leather having a full-bodied touch, a leather-like appearance, and physical properties that can withstand practical use can be obtained. The main component here means that the mass of the polyurethane is more than 50% by mass relative to the mass of the entire polymer elastomer.

By using the polymer elastomer, artificial leather having a feeling of fullness, a leather-like appearance, and physical properties that can withstand practical use can be obtained.

When the polyurethane is used in the present invention, any of an organic solvent-based polyurethane used in a state of being dissolved in an organic solvent and a water dispersion-type polyurethane used in a state of being dispersed in water can be used. In addition, as the polyurethane, a polyurethane obtained by a reaction of a polymer diol with an organic diisocyanate and a chain extender can be preferably used. In addition, from the viewpoint of reducing environmental load, it is preferable to contain a component derived from a biomass resource. In particular, when polyurethane is used as the polymer elastomer as the component derived from the biomass resource, it is preferable to use the component derived from the biomass resource in the polymer diol whose structural component is relatively easily purchased as the raw material derived from the biomass resource. Hereinafter, preferred embodiments of the components constituting the polyurethane when the polyurethane is used as the polymer elastomer in the present invention will be further described.

< Polymer diol >

When polyurethane is used as the polymer elastomer, polyester diol, polyether diol, polycarbonate diol, or at least one polymer diol selected from polymer diols such as polyester diol and polyether diol can be used as a preferable polymer diol, but it is preferable to contain polycarbonate diol having excellent hydrolysis resistance.

The polycarbonate diol can be produced by a transesterification reaction between an alkanediol and a carbonate, a reaction between phosgene or a chloroformate and an alkanediol, or the like.

Examples of the alkanediol include: straight-chain alkanediols such as "ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 9-nonanediol and 1, 10-decanediol", branched alkanediols such as "neopentyl glycol, 3-methyl-1, 5-pentanediol, 2, 4-diethyl-1, 5-pentanediol and 2-methyl-1, 8-octanediol", alicyclic diols such as 1, 4-cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylolpropane and pentaerythritol. In the present invention, the alkylene glycol may be either a polycarbonate-based glycol obtained from each alkylene glycol alone or a copolymerized polycarbonate-based glycol obtained from two or more kinds of alkylene glycols.

Examples of the polyester diol include polyester diols obtained by condensing various low molecular weight polyols with a polybasic acid.

As the low molecular weight polyol, for example, one or more selected from the group consisting of ethylene glycol, 1, 2-propanediol, 1, 3-butanediol, 1, 4-butanediol, 2-dimethyl-1, 3-propanediol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, 1, 8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1, 4-diol, and cyclohexane-1, 4-dimethanol can be used. In addition, adducts obtained by adding various alkylene oxides to bisphenol A can also be used.

Examples of the polybasic acid include one or more selected from succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydroisophthalic acid.

Examples of the polyether glycol include: polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and a combination thereof.

The number average molecular weight of the polymer diol used in the present invention is preferably 500 or more and 4000 or more. By setting the number average molecular weight to preferably 500 or more, more preferably 1500 or more, the artificial leather can be prevented from becoming hard in texture. Further, by setting the number average molecular weight to preferably 4000 or less, more preferably 3000 or less, the strength as polyurethane can be maintained.

In the case of using the biomass-derived component in the polymer diol, the polymer diol may include only the biomass-derived component, or may include a copolymer of the biomass-derived polymer diol and a petroleum-derived polymer diol. From the viewpoint of reducing the environmental load, it is preferable that the amount of the polymer diol derived from a biomass resource is larger than that of the polymer diol derived from a petroleum resource.

< organic diisocyanate >

When polyurethane is used as the polymer elastomer, examples of the organic diisocyanate used include aliphatic diisocyanates such as "hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylene diisocyanate", and aromatic diisocyanates such as "4,4' -diphenylmethane diisocyanate, and toluene diisocyanate", and these may be used in combination. Among them, when importance is attached to durability or heat resistance, aromatic diisocyanates such as 4,4' -diphenylmethane diisocyanate are preferable, and when importance is attached to light resistance, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and the like are preferably used. One of these organic diisocyanates may be used, or two or more of them may be used in combination.

< chain elongation agent >

When polyurethane is used as the polymer elastomer, preferable examples of the chain extender include at least one low molecular weight compound having two or more active hydrogen atoms such as water, ethylene glycol, butanediol, ethylenediamine, and 4,4' -diaminodiphenylmethane. From the viewpoint of reducing environmental load, it is preferable to use a chain extender containing a component derived from a biomass resource.

< crosslinking agent >

When polyurethane is used as the polymer elastomer, a crosslinking agent may be used in combination as needed for the purpose of improving water resistance, abrasion resistance, hydrolysis resistance, and the like. The crosslinking agent may be an external crosslinking agent added as a third component to the polyurethane, or may be an internal crosslinking agent in which a reaction site to be a crosslinked structure is introduced in advance in the molecular structure of the polyurethane. In the present invention, it is preferable to use an internal crosslinking agent from the viewpoint that crosslinking points can be formed more uniformly in the molecular structure of the polyurethane and the decrease in flexibility can be reduced.

As the crosslinking agent, compounds having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, and the like can be used. Among them, when the crosslinking is excessively progressed, the polyurethane is hardened, and the hand of the artificial leather tends to be hardened, and therefore, a crosslinking agent having a silanol group is preferably used in terms of balance between reactivity and flexibility.

When the water dispersion type polyurethane is used in the present invention, an internal emulsifier is preferably used in order to disperse the polyurethane in water. Examples of the internal emulsifier include: a cationic internal emulsifier such as a quaternary ammonium salt, an anionic internal emulsifier such as a sulfonate or a carboxylate, and a nonionic internal emulsifier such as polyethylene glycol, and further, any of a combination of a cationic and nonionic internal emulsifiers, and a combination of an anionic and nonionic internal emulsifiers can be used. Among them, nonionic internal emulsifiers are preferable from the viewpoint that they are superior in light resistance to cationic internal emulsifiers and are free from adverse effects caused by neutralizing agents to anionic internal emulsifiers.

< other additives >

The polymer elastomer may contain various additives depending on the purpose, for example, a pigment such as carbon black, a flame retardant such as phosphorus, halogen, and inorganic flame retardants, an ultraviolet absorber such as phenol, sulfur, and phosphorus antioxidants, benzotriazole, benzophenone, salicylate, cyanoacrylate, and oxanilide (oxyacid anilide), a light stabilizer such as hindered amine or benzoate, a hydrolysis resistance stabilizer such as polycarbodiimide, a plasticizer, an antistatic agent, a surfactant, a coagulation regulator, and a dye.

The polymer elastomer used in the present invention may include polyester, polyamide, polyolefin, and other elastomer resins, acrylic resins, ethylene-vinyl acetate resins, and the like, as long as the performance or feel as an adhesive is not impaired.

The content of the polymer elastomer in the artificial leather can be appropriately adjusted in consideration of the kind of the polymer elastomer to be used, the production method of the polymer elastomer, and the hand feeling or physical properties. The content of the polymeric elastomer is preferably 10 mass% or more and 60 mass% or less with respect to the mass of the nonwoven fabric (when the nonwoven fabric and the woven fabric are entangled and integrated, the total mass of the nonwoven fabric and the woven fabric is referred to). By setting the content of the polymeric elastomer to preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more with respect to the mass of the nonwoven fabric, the bonding between the fibers constituting the nonwoven fabric by the polymeric elastomer can be improved, and the abrasion resistance of the artificial leather can be improved. On the other hand, by setting the content of the polymeric elastomer to preferably 60% by mass or less, more preferably 45% by mass or less, and further preferably 40% by mass or less with respect to the mass of the nonwoven fabric, artificial leather having a soft hand of artificial leather can be produced.

In the polymer elastomer for artificial leather of the present invention, the degree of bio-plastics defined in ISO16620 (2015) is preferably 5% or more and 100% or less. Further, the biomass plasticity of the polymer elastomer is more preferably 15% or more, and even more preferably 25% or more, in order to further reduce the environmental load or improve the hand feeling of the artificial leather.

In order to measure the degree of bio-plastomery of the polymer elastomer, examples of the separation of the polymer elastomer from the artificial leather include: a method of extracting and separating the components of the elastic polymer with a solvent in which only the elastic polymer is soluble, or a method of removing these components from the artificial leather with a solvent in which the microfine fibers and the resin layer are soluble. Can be suitably used according to the structural components of the artificial leather. Except for this, the measurement is performed by basically the same method as the biomass plasticity of the nonwoven fabric.

If the polymer elastomer is soluble in an organic solvent, the polymer elastomer can be separated by extracting it with an organic solvent such as N, N-dimethylformamide. When the polymer elastomer is obtained from a water-dispersible type, a method of removing the fiber by using a solvent for dissolving the fiber (in the case of polyester, 1,1,1,3,3,3-hexafluoro-2-propanol, o-chlorophenol, or the like) can be exemplified. In addition, a method of extracting the water-dispersed polymer elastomer by decomposing it with N, N-dimethylformamide heated to 60 ℃ or higher and 100 ℃ or lower can be used.

When the resin layer described later is dissolved in the same solvent as the polymeric elastomer, the polymeric elastomer can be separated by the above-described method by previously slicing or peeling off and removing the resin layer.

[ Artificial leather ]

The artificial leather of the present invention includes the nonwoven fabric and the polymer elastomer as constituent elements, and satisfies the following formulae (a) and (b).

0.5≦F _A /F _B ＜1 ···(a)

0.5≦F _C /F _B ＜1 ···(b)

That is, it is important to reduce the density of fibers in the layer on one surface side and the layer on the other surface side and to increase the density of fibers in the layer at the center in the thickness direction.

As in the above formula (a), by reducing the density of the fibers in the layer on one surface side with respect to the layer in the center in the thickness direction, fuzzing is easily caused, and a dense and soft-touch surface quality can be obtained. In addition, the artificial leather can be imparted with soft softness. Further, as in the above formula (b), by decreasing the density of the fibers in the layer on the other surface side with respect to the layer at the center in the thickness direction, soft flexibility can be imparted to the artificial leather. As shown in formulas (a) and (b), by reducing the density of fibers in the layer on one surface side and the layer on the other surface side with respect to the layer at the center in the thickness direction, not only can soft flexibility be provided, but also the occurrence of fold wrinkles or sagging of the sheet when it is bent can be suppressed. On the other hand, by increasing the density of the fibers in the layer at the center in the thickness direction, the artificial leather can be provided with a moderate resilient feeling. Specifically, the density ratio (F) of the fibers is determined _A /F _B Or F _C /F _B ) The content is less than 1, preferably 0.95 or less, more preferably 0.9 or less, further preferably 0.85 or less, and particularly preferably 0.8 or less, and one surface is likely to have fuzz, and a dense and soft-touch surface quality is likely to be formed. Further, by setting the ratio of the fiber density to 0.5 or more, preferably 0.6 or more, and more preferably 0.65 or more, both soft softness and a springback feeling can be achieved.

In the present invention, said F _A 、F _B 、F _C Each can be measured as follows. As described below, the density of the fibers in the present invention means the density of a fiber structure including the ultrafine fibers constituting the nonwoven fabric and the woven fabric when the woven fabric is laminated inside or on one side of the nonwoven fabric and entangled to be integrated therewith.

(1) For the artificial leather, a 20cm × 20cm sample was used, and the sample was divided into three equal parts in the thickness direction.

(2) As shown in fig. 1, the artificial leather 11 is divided into a layer (a) on one surface side, a layer (B) at the center in the thickness direction, and a layer (C) on the other surface side. In the case of the layer (a) in which the pile layer is formed on the surface side, the pile layer is divided into three equal parts in the thickness direction. As shown in fig. 3, when the resin layer is disposed on the pile layer in the layer (a) on one surface side, the portion including the resin layer is the layer (D) on one surface side, and is divided into the layer (E) at the center in the thickness direction and the layer (F) on the other surface side in the same manner. Then, the divided sample was immersed in N, N-dimethylformamide for 8 hours, and the polymer elastomer was completely extracted.

(3) The sample was sufficiently dried, the mass of the dried sample was measured, and the density of the fibers in each layer was calculated by the following formula.

Density of fiber (g/cm) ³ ) = sample mass after extraction (g)/(20 (cm) × 20 (cm) × thickness of sample before extraction (cm))

The thickness of the sample before extraction was determined by taking ten images of different portions of the cross section of the sample before extraction at a magnification of 200 times using a scanning electron microscope, and obtaining the thickness of the sample from these respective taken images. In the case of having the pile layer, the thickness after removing the thickness of the pile layer was taken as the thickness of the sample.

(4) Using the calculated F _A And F _B 、F _C The density ratio (F) of the fibers was calculated _A /F _B Or F _C /F _B ) The average of the values measured for ten points was taken as the result.

The artificial leather of the present invention preferably has at least one raised layer formed by raising. By having the pile layer, the natural leather-like surface feeling can be obtained, and the adhesiveness to the resin layer described later is excellent. Further, the raised fibers exposed on the surface of the artificial leather having the intermittently formed resin layer can provide a surface texture closer to that of natural leather.

The artificial leather of the present invention preferably has at least one resin layer. By providing the resin layer, the natural leather-like surface texture in a grain (grained) or mat shape can be obtained. In this case, the resin layer is also preferably formed intermittently in the surface of the artificial leather.

By intermittently forming the resin layer, the raised part, which is a part of the raised layer exposed as a part where no non-resin layer is present, can ensure sufficient air permeability of the artificial leather, and can maintain good quality and hand feeling without breaking the resin layer even when the artificial leather is bent.

In the present invention, the phrase "the resin layer is intermittently formed in the surface of the artificial leather" means a state in which the resin layer 2 in which the layered resin is dispersed in island form is disposed on the surface of the artificial leather as seen from above the artificial leather as illustrated in fig. 2 and also on the pile layer 1 continuously present therebelow. In the top view, the resin layer and the exposed raised portion are present, and the resin layer 2 is surrounded by the raised layer 1 and has an independent shape, for example. Fig. 3 shows an example of a cross section of the artificial leather in this case. The island-like resin layer 2 may be regularly present, but the shape and arrangement of the resin layer 2 are preferably random in order to obtain a surface feeling closer to natural leather by the random shape and arrangement.

The area ratio of the resin layer on the surface of the artificial leather is preferably 10-90%. By setting the above ratio to 10% or more, preferably 20% or more, artificial leather having a resin-containing layer which is excellent in abrasion resistance and has a frosted or grain-like surface feel and a tactile sensation can be produced. On the other hand, by setting the above ratio to 90% or less, preferably 80% or less, the artificial leather containing the resin layer can be provided with air permeability or a raised feeling like a suede-like substrate.

The resin layer preferably includes at least two layers. More preferably at least three layers. More preferably, the resin layer has a three-layer structure of an adhesive layer, an intermediate layer and a surface layer. Here, the adhesive layer has a function of adhering the fiber structure to the intermediate layer. The next layer is a resin layer excellent in adhesion to the fibers of the pile layer in which the ultrafine fibers of the fiber structure are raised and the intermediate layer, and the presence of the next layer between these layers improves the adhesion between the fiber structure and the resin layer, thereby providing artificial leather excellent in abrasion resistance.

Further, by providing two or more resin layers, artificial leather having excellent abrasion resistance, which is further required to have durability, such as car seats and sofas, can be obtained. In the case where the resin layer is one layer, the abrasion resistance is poor.

The resin used in the resin layer is preferably a resin having elastic rubber elasticity, and examples thereof include: polyurethane, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), acrylic resin, and the like. Among them, a material containing polyurethane as a main component, specifically, a material containing 50 mass% or more of polyurethane can be preferably used in terms of achieving a balance between the texture and the physical properties.

As described above, the polyurethane includes organic solvent-based polyurethane used in a state of being dissolved in an organic solvent, water dispersion-type polyurethane used in a state of being dispersed in water, and the like, but any of them can be used in the present invention.

In the present invention, as the polyurethane used for the resin layer, a polyurethane obtained by a reaction of a polymer diol with an organic diisocyanate and a chain extender can be preferably used. In addition, from the viewpoint of reducing environmental load, it is preferable that the biomass-derived component is contained. In particular, when polyurethane is used as the resin used in the resin layer as the component derived from the biomass resource, it is preferable to use the component derived from the biomass resource in a polymer diol whose structural component is relatively easily available as a raw material derived from the biomass resource. Hereinafter, preferred embodiments of the components constituting the polyurethane when the polyurethane is used as a resin used in the resin layer in the present invention will be further described.

< Polymer diol >

When polyurethane is used as the resin layer, examples of preferable polymer diols include polycarbonate diol, polyester diol, polyether diol, silicone diol, and fluorine diol, or a copolymer of a combination of these diols. Among them, polycarbonate diols and polyester diols can be preferably used from the viewpoint of light resistance. Further, from the viewpoint of hydrolysis resistance and heat resistance, a polycarbonate diol can be preferably used. In the adhesion layer, polyether glycol or polyester glycol may be preferably used in terms of adhesion to the surface of the artificial leather.

Examples of the alkylene glycol include: straight chain alkanediols such as "ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 9-nonanediol and 1, 10-decanediol", branched alkanediols such as "neopentyl glycol, 3-methyl-1, 5-pentanediol, 2, 4-diethyl-1, 5-pentanediol and 2-methyl-1, 8-octanediol", alicyclic diols such as 1, 4-cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylolpropane and pentaerythritol.

In the present invention, any of polycarbonate diols obtained from each individual alkanediol, and copolymerized polycarbonate diols obtained from two or more alkanediols may be used.

< organic diisocyanate >

In the case of using polyurethane as the resin used in the resin layer, preferable organic diisocyanates to be reacted with the polymer diol include, for example: aliphatic polyisocyanates such as "hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylene diisocyanate", and aromatic polyisocyanates such as "4,4' -diphenylmethane diisocyanate, and toluene diisocyanate". These may be used in combination. Among them, aromatic polyisocyanates such as 4,4' -diphenylmethane diisocyanate are preferable when importance is attached to durability and heat resistance. When importance is attached to light resistance, aliphatic polyisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferable. One of these organic diisocyanates may be used, or two or more of them may be used in combination.

< chain extender >

When polyurethane is used as the resin layer, preferable examples of the chain extender include at least one low molecular weight compound having two or more active hydrogen atoms such as water, ethylene glycol, butanediol, ethylenediamine, and 4,4' -diaminodiphenylmethane.

< other additives >

The resin used in the resin layer of the present invention may contain polyester, polyamide, polyolefin, or other elastomer resins, acrylic resins, ethylene-vinyl acetate resins, and the like, as long as the abrasion resistance and the texture are not impaired. These resins may contain various additives, for example, pigments such as carbon black, flame retardants such as phosphorus, halogen and inorganic materials, antioxidants such as phenol, sulfur and phosphorus materials, light stabilizers such as hindered amine and benzoate, hydrolysis resistant stabilizers such as polycarbodiimide, plasticizers, antistatic agents, surfactants, setting regulators, and dyes.

The thickness of the resin layer is not particularly limited, but the total thickness is preferably 0.001mm or more and 0.500mm or less. When the total thickness is 0.001mm or more, more preferably 0.010mm or more, and still more preferably 0.050mm or more, the artificial leather containing the resin layer excellent in abrasion resistance can be obtained. On the other hand, when the total thickness is 0.500mm or less, more preferably 0.400mm or less, and still more preferably 0.300mm or less, artificial leather having a resin-containing layer with a soft texture can be obtained.

In addition, the thickness of each layer of the resin layer is preferably 0.001mm or more and 0.200mm or less for the first layer and the second layer, respectively, and 0.008mm or more and 0.300mm or less for the third layer.

In the present invention, the total thickness of the resin layer of the artificial leather is measured as follows.

(1) A cross section perpendicular to the plane direction and the machine direction of the artificial leather is cut out and set on a sample stage so that the cross section is not deformed.

(2) Ten sections of the sample pieces of artificial leather were photographed at a magnification of 200 times using a scanning electron microscope.

(3) From these captured images, the distance between two points, i.e., the highest position z1 and the lowest position z2 of the resin layer when the direction parallel to the cross section is horizontal and the pile side of the cross section is the upper side and the other side is the lower side, is obtained, and the total thickness of the resin layer is calculated.

(4) The average value of the ten calculated values was defined as the total thickness of the resin layer.

The artificial leather of the present invention preferably further satisfies the following formulae (c) and (d).

0.6≦P _A /P _B ＜1 ···(c)

0.6≦P _C /P _B ＜1 ···(d)

That is, it is preferable to reduce the density of the elastic polymer in the layer on one surface side and the layer on the other surface side, and to increase the density of the elastic polymer in the layer at the center in the thickness direction, similarly to the fiber density.

As shown in the above formula (c), the density of the high molecular elastomer in the layer on one surface side is reduced with respect to the layer at the center in the thickness direction, so that fuzzing is facilitated and a dense and soft surface quality can be obtained. In addition, the artificial leather can be imparted with soft softness. Further, as in the above formula (d), by decreasing the density of the elastic polymer in the layer on the other surface side with respect to the layer at the center in the thickness direction, soft flexibility can be imparted to the artificial leather. As shown in formulas (c) and (d), by reducing the density of the elastic polymer in the layer on one surface side and the layer on the other surface side with respect to the layer at the center in the thickness direction, not only can soft flexibility be provided, but also the occurrence of fold wrinkles or sagging of the sheet when it is bent can be suppressed. On the other hand, by increasing the thickness direction of the central layerThe density of the polymer elastomer of (2) can give a moderate resilient feeling to the artificial leather. Specifically, the ratio (P) of the densities of the polymeric elastomers is determined _A /P _B Or P _C /P _B ) The surface is less than 1, preferably 0.95 or less, more preferably 0.9 or less, still more preferably 0.85 or less, and particularly preferably 0.8 or less, and the surface is likely to have fluffs, and a dense and soft-touch surface quality is likely to be formed. Further, by setting the ratio of the densities of the polymeric elastic bodies to 0.6 or more, preferably 0.7 or more, and more preferably 0.75 or more, both soft flexibility and a springback feeling can be achieved.

In the present invention, said P _A 、P _B 、P _C Each can be measured as follows.

(2) As shown in fig. 1, the layer (a) on one surface side, the layer (B) at the center in the thickness direction, and the layer (C) on the other surface side are divided. As shown in fig. 3, when the resin layer is disposed on the pile layer in the layer (a) on one surface side, the portion including the resin layer is the layer (D) on one surface side, and is divided into the layer (E) at the center in the thickness direction and the layer (F) on the other surface side in the same manner. In this case, the resin layer of the layer (D) present on one surface side is removed. Then, the divided sample was immersed in N, N-dimethylformamide for 8 hours, and the polymer elastomer was completely extracted.

(3) The samples were sufficiently dried, the mass of the dried samples was measured, and the density of the polymer elastomer in each layer was calculated by the following formula.

Density (g/cm) of high molecular elastomer ³ ) = (sample mass before extraction (g) — sample mass after extraction (g))/(20 (cm) × 20 (cm) × thickness of sample before extraction (cm))

The thickness of the sample before extraction was determined from ten images of different portions of the cross section of the sample before extraction taken at a magnification of 200 times using a scanning electron microscope. In the case of having the pile layer, the thickness after removing the thickness of the pile layer was taken as the thickness of the sample.

(4) Using the calculated P _A And P _B 、P _C The density ratio (P) of the polymer elastomer was calculated _A /P _B Or P _C /P _B ) The average of the values measured for ten points was taken as the result.

In the artificial leather of the present invention, the density of the whole artificial leather is preferably 0.20g/cm ³ Above and 0.70g/cm ³ The following. By setting the density to 0.20g/cm ³ As described above, the appropriate springback feeling of the artificial leather can be secured, and the density is set to 0.70g/cm ³ The hand feeling of the artificial leather is improved as follows. The density of the whole artificial leather is more preferably 0.22g/cm ³ Above and 0.60g/cm ³ Hereinafter, more preferably 0.25g/cm ³ Above and 0.50g/cm ³ The following.

In the present invention, the density of the whole artificial leather is an average value of values obtained by calculating the density of the whole artificial leather from the following expression using the mass of a sample of 20cm × 20cm with respect to the artificial leather and measuring the density at ten points.

Density (g/cm) of the whole artificial leather ³ ) = sample mass (g)/(20 (cm) × 20 (cm) × sample thickness (cm)).

From the viewpoint of satisfying both the soft flexibility and the appropriate springback feeling of the artificial leather, the thickness of the artificial leather of the present invention is preferably 0.8mm or more and 4.0mm or less, and more preferably 0.9mm or more and 3.5mm or less.

In the present invention, the thickness of the artificial leather is an arithmetic average of values measured at ten points in the width direction of the artificial leather by using a thickness measuring instrument (for example, a needle dial thickness gauge "PEACOCK (PEACOCK) model H" manufactured by kazaki corporation).

The artificial leather of the present invention contains, for example, dyes, pigments, softening agents, texture modifiers, anti-pilling agents, antibacterial agents, deodorants, water-repellent agents, light-resistant agents, weather-resistant agents, and the like, and is also a preferred embodiment.

[ Process for producing Artificial leather ]

Next, an example of a method for producing the artificial leather of the present invention will be described.

The method for producing artificial leather of the present invention is preferably a method for producing artificial leather comprising a nonwoven fabric comprising microfine fibers having an average single fiber diameter of 0.1 to 10 μm and a polymeric elastomer as constituent elements, and comprises the following steps (i) to (v) in this order.

(i) A step of interlacing microfine fiber-forming fibers comprising two or more thermoplastic resins having different solubilities in a solvent to produce a nonwoven fabric

(ii) Impregnating the nonwoven fabric with an aqueous solution of a water-soluble resin, and drying the impregnated nonwoven fabric at 110 ℃ or higher to impart the water-soluble resin thereto

(iii) Compressing the water-soluble resin-added nonwoven fabric in the thickness direction and sheeting

(iv) (iv) a step of treating the sheet obtained in the above (iii) with a solvent to develop ultrafine fibers having an average fiber diameter of single fibers of 0.1 to 10 μm, and then impregnating the sheet with a solvent solution of an elastic polymer and curing the impregnated sheet to provide an elastic polymer, or

(iv) impregnating the sheet obtained in the above (iii) with a solvent solution of a polymer elastomer and curing the impregnated sheet to give a polymer elastomer, and then treating the sheet with a solvent to obtain an ultrafine fiber having a single fiber average fiber diameter of 0.1 μm or more and 10 μm or less

(v) (iii) a step of forming a pile on at least one surface without dividing the sheet obtained in the (iv) into a plurality in the thickness direction

By sequentially carrying out the steps (i) to (v), an artificial leather having soft softness and a moderate resilient feeling can be obtained.

First, step (i) will be explained.

In step (i), a nonwoven fabric is produced by interlacing microfine fiber-forming fibers comprising two or more thermoplastic resins having different solubilities in a solvent.

After the ultrafine fiber-generating fibers are previously entangled to form a nonwoven fabric, the fibers are made ultrafine in the subsequent step (iv), whereby a nonwoven fabric in which ultrafine fibers are entangled can be obtained.

As the ultrafine fiber-generating fiber, the following fibers and the like can be used: a sea-island type composite fiber in which two thermoplastic resins having different solvent solubilities are used as a sea component and an island component, and the sea component is dissolved and removed with a solvent or the like to obtain an ultrafine fiber of the island component; or a composite fiber of a split type in which a fiber cross section is alternately arranged in a radial shape or a multi-layer shape with respect to thermoplastic resins of two components, and the components are split and divided, thereby dividing the fiber into ultrafine fibers. Among them, the sea-island type composite fiber can be preferably used from the viewpoint of hand and surface quality because a suitable void can be provided between island components, that is, between ultrafine fibers in a fiber bundle by removing a sea component.

The sea-island type composite fiber can be obtained by, for example: using a die orifice for sea-island type compounding, and using a mode of a polymer mutual arrangement body for mutually arranging and spinning the sea component and the island component; in the case of a mixed spinning method in which a sea component and an island component are mixed and spun, a sea-island type composite fiber using a polymer matrix can be preferably used in order to obtain ultrafine fibers having a uniform fineness.

When the nonwoven fabric is a short fiber nonwoven fabric, the obtained ultrafine fiber-developing fiber is preferably crimped and cut to a predetermined length to obtain raw cotton. The crimping process or the cutting process may use a known method.

Next, the obtained raw cotton is made into a web by a cross lapper (cross lapper) or the like and entangled, thereby obtaining a nonwoven fabric. As a method of interlacing the web to obtain a nonwoven fabric, needle punching (needle punch), water punching (water jet punch), or the like can be used.

In order to increase the fiber density, it is also preferable to apply a heat shrinkage treatment by hot water or steam treatment to the nonwoven fabric.

Next, step (ii) will be described.

In step (ii), the nonwoven fabric is impregnated with an aqueous solution of a water-soluble resin, and dried at 110 ℃ or higher to impart the water-soluble resin. Thereby, the water-soluble resin is biased to be present on both surface layer sides of the nonwoven fabric by migration, and the water-soluble resin is provided to the nonwoven fabric. By applying a water-soluble resin to the nonwoven fabric, the fibers are fixed and the dimensional stability is improved, and by applying a water-soluble resin so as to be biased to be present on both surface layer portions of the nonwoven fabric, when the nonwoven fabric is compressed in the thickness direction in the subsequent step (iii), the inner layer portion side having a low amount of the water-soluble resin and a low dimensional stability is preferentially compressed, and as a result, a structure having a low fiber density in both surface layer portions and a high fiber density in the inner layer portion is formed. In the subsequent step (iv), when the polymer elastomer is applied after the ultrafine fibers are developed, the water-soluble resin is biased to be present on both surface portions, so that the polymer elastomer is less in both surface portions where the water-soluble resin is large, and the adhesion area between the ultrafine fibers and the polymer elastomer is reduced by being hindered by the water-soluble resin. The nonwoven fabric containing less water-soluble resin can be provided with more polymer elastomer on the inner layer side, and the bonding area between the microfine fiber and the polymer elastomer is increased.

The fiber sheet obtained in the above-described manner has low fiber density and low density of the polymer elastomer on both surface layer sides, and has a small adhesion area between the two, so that fluffing is easy, a dense and soft-touch product surface can be formed, and soft flexibility can be imparted to the artificial leather. On the other hand, the inner layer side has a high density of the fibers and the elastic polymer and a large contact area between the fibers and the elastic polymer, and therefore, the artificial leather can be provided with a moderate resilient feeling. The fiber sheet obtained in the above manner is not divided into a plurality of pieces in step (v), but at least one surface is fluffed, thereby satisfying the following formulae (a) and (b) which are important requirements of the present invention.

0.5≦F _A /F _B ＜1 ···(a)

0.5≦F _C /F _B ＜1 ···(b)

Here, F _A 、F _B 、F _C Respectively is to make the artificial leatherThe density (g/cm) of the fibers in the layer on one surface side divided into three equal parts in the thickness direction ³ ) The density (g/cm) of the fibers in the layer at the center in the thickness direction ³ ) The density (g/cm) of the fibers in the layer on the other surface side ³ )。

In the present invention, as the water-soluble resin, polyvinyl alcohol having a saponification degree of 80% or more can be preferably used.

Examples of the method of applying the water-soluble resin to the nonwoven fabric include a method of impregnating the nonwoven fabric with an aqueous solution of the water-soluble resin and drying the impregnated nonwoven fabric. The concentration of the aqueous solution of the water-soluble resin is preferably 1% or more and 20% or less. In order to further migrate, it is important that the drying temperature is 110 ℃ or higher.

The amount of the water-soluble resin to be applied is preferably 5% by mass or more and 60% by mass or less with respect to the nonwoven fabric (sheet) immediately before the application. The structure can be made by setting the added amount to 5 mass% or more, more preferably 10 mass% or more. Further, by setting the addition amount to 60% by mass or less, more preferably 50% by mass or less, a processed intermediate sheet and artificial leather having good processability and good physical properties such as abrasion resistance can be obtained.

The water-soluble resin added to the nonwoven fabric is removed by hot water or the like after the polymeric elastomer is added in step (iv).

Next, step (iii) will be described.

In step (iii), the nonwoven fabric to which the water-soluble resin is added is compressed in the thickness direction and formed into a sheet. As described above, it is important to compress the nonwoven fabric containing the ultrafine fibers, which is imparted by transferring the water-soluble resin, in the thickness direction. Thus, since the water-soluble resin is small and the inner layer side of the nonwoven fabric to which the polar fibers are not fixed is preferentially compressed, the fiber density of the inner layer side becomes higher than that of the surface layer side.

The method of compressing the nonwoven fabric may be performed simultaneously with the calendering or the squeezing of the solvent used in the developing treatment of the ultra-fine fibers.

Next, step (iv) will be described.

In the step (iv), the sheet obtained in the step (iii) is treated with a solvent to develop ultrafine fibers having an average single fiber diameter of 0.1 μm or more and 10 μm or less, and then the sheet is impregnated with a solvent solution for a polymer elastomer and cured to give a polymer elastomer, or the sheet obtained in the step (iii) is impregnated with a solvent solution for a polymer elastomer and cured to give a polymer elastomer, and then the sheet is treated with a solvent to develop ultrafine fibers having an average single fiber diameter of 0.1 μm or more and 10 μm or less.

The ultrafine fibers can be developed by impregnating a nonwoven fabric containing sea-island type composite fibers in a solvent and dissolving and removing the sea component.

When the ultrafine fiber-developing fiber is a sea-island type composite fiber, an organic solvent such as toluene or trichloroethylene may be used as a solvent for dissolving and removing the sea component, and when the sea component is polyethylene, polypropylene or polystyrene. When the sea component is a copolyester or polylactic acid, an aqueous alkali solution such as sodium hydroxide may be used. In the case where the sea component is a water-soluble thermoplastic polyvinyl alcohol resin, hot water may be used.

As a method for fixing the elastic polymer to the sheet made of the nonwoven fabric, there is a method of impregnating the sheet with a solution of the elastic polymer and performing wet coagulation or dry coagulation, and the method can be appropriately selected depending on the type of polyurethane used.

Next, step (v) will be described.

In the step (v), at least one side is raised and raised without dividing the sheet obtained in the step (iv) into a plurality in the thickness direction.

The raising treatment may be performed on both sides. As described above, the surface having a low ratio of the fiber to the polymer elastomer is easily fluffed, and a soft touch can be obtained.

The raising treatment can be applied by a method of grinding using sandpaper, a roll sander, or the like. A lubricant such as a silicone emulsion may be imparted before the raising treatment. In addition, when an antistatic agent is applied before the raising treatment, abrasive powder generated from the sheet by polishing is not easily deposited on the sandpaper, and therefore, this is a preferable form.

According to the present invention, since the fiber density and the polymer elastomer density on the pile side and the other side in the thickness direction are low, the pile is easily raised, the surface quality with a dense and soft touch can be obtained, and soft flexibility can be provided. By setting the center in the thickness direction to artificial leather having a high fiber density and a high polymer elastomer density, a moderate resilient feeling can be imparted to the artificial leather. Accordingly, the soft flexibility and the appropriate springback feeling can be both achieved, and the occurrence of fold and wrinkle or sagging when the sheet is bent can be suppressed.

The artificial leather of the present invention can be dyed. The dye may be selected in combination with the ultrafine fibers constituting the artificial leather. For example, a disperse dye may be used in the case where the ultrafine fibers include polyester fibers, and an acid dye or a gold-containing dye may be used in the case where the ultrafine fibers include polyamide fibers. In the case of dyeing with a disperse dye, it is preferable to perform reduction washing after dyeing.

In addition, for the purpose of improving uniformity and reproducibility of dyeing, the use of a dyeing assistant is also a preferable form.

The artificial leather of the present invention may be treated with a softening agent such as silicone or a finishing agent (finishing agent) such as an antistatic agent. The treatment with the modifying agent may be carried out after dyeing or in the same bath as dyeing.

Further, the artificial leather of the present invention may be formed with a resin layer. Examples of the method for forming the resin layer in the present invention include: a method of forming a resin layer by coating and drying the resin layer by a screen printing method such as a flat screen (flat screen) or a rotary screen (gravure) method, or a method of forming a resin layer by continuously or intermittently forming a resin film on a supporting base fiber such as a release paper, coating an adhesive on the surface of the resin film, bonding the resin film to the surface of a fiber structure, and then peeling the release paper.

In the present invention, it is preferable that the resin layer is intermittently formed on the surface layer of the raised surface of the artificial leather. Further, in order to make the resin layer two or three layers, it can be formed by repeating the method twice or three times. The same method can be repeated, and two or more kinds can be used in combination.

In addition, designability may be applied to the surface of the artificial leather as needed. For example, a hole-forming process such as punching, an embossing process, a laser process, a pingnic process, and a post-processing process such as a printing process may be performed.

Examples

Next, the artificial leather of the present invention will be described with reference to examples. Further, the measurement was performed according to the above-described method for matters not specifically described.

< fiber Density within layer >

The obtained artificial leather was divided into three equal parts in the thickness direction of a 20cm × 20cm sample, i.e., a layer (a) on one surface side, a layer (B) at the center in the thickness direction, and a layer (C) on the other surface side by using a microtome. The thickness of the trisected samples was measured at a magnification of 200 times using a scanning electron microscope, and it was confirmed that the three samples had the same thickness. Then, the divided sample was immersed in N, N-dimethylformamide for 8 hours, and the polymer elastomer was completely extracted. Thereafter, the N, N-dimethylformamide contained in the sample was rinsed with water, and the sample was sufficiently dried at 100 ℃x20 minutes with a hot air dryer. The mass of the dried sample was measured, and the density of the fibers in each layer was calculated by the following formula.

The thickness of the sample before extraction in the calculation of the fiber density was determined by taking ten images of different portions of the cross section of the sample before extraction at a magnification of 200 times using a scanning electron microscope and obtaining the thickness of the sample from the respective images taken. In the case of having the pile layer, the thickness after removing the thickness of the pile layer was taken as the thickness of the sample.

Using the calculated F _A And F _B 、F _C The density ratio (F) of the fibers was calculated _A /F _B Or F _C /F _B ) The average of the values measured for ten points was taken as the result.

< Density of Polymer elastomer in layer >

The obtained artificial leather was divided into three equal parts in the thickness direction of a 20cm × 20cm sample, i.e., a layer (a) on one surface side, a layer (B) at the center in the thickness direction, and a layer (C) on the other surface side by using a microtome. The thickness of the trisected samples was measured, and it was confirmed that the three samples had the same thickness. Then, the divided sample was immersed in N, N-dimethylformamide for 8 hours, and the elastomer was completely extracted. Thereafter, the N, N-dimethylformamide contained in the sample was rinsed with water, and the sample was sufficiently dried at 100 ℃x20 minutes with a hot air dryer. The mass of the dried sample was measured, and the density of the polymer elastomer in each layer was calculated by the following formula.

Density (g/cm) of polymer elastomer ³ ) = (sample mass before extraction (g) -sample mass after extraction (g))/(20 (cm) × 20 (cm) × thickness of sample before extraction (cm))

The thickness of the sample before extraction in the calculation of the density of the elastic polymer was determined by taking ten images of different portions of the cross section of the sample before extraction at a magnification of 200 times using a scanning electron microscope and obtaining the thickness of the sample from these respective taken images. In the case of having the pile layer, the thickness after removing the thickness of the pile layer was taken as the thickness of the sample.

Using the calculated P _A And P _B 、P _C The density ratio (P) of the polymer elastomer was calculated _A /P _B Or P _C /P _B ) The average of the values measured for ten points was taken as the result.

< evaluation method >

(1) Surface grade:

ten healthy adult males and adult females were evaluated as one of the evaluators in total, and the evaluation was performed as described in the following 5 to 1 by visual observation and sensory evaluation, and the most evaluated was regarded as the appearance quality. The preferable level in the present invention is 4 or more.

5: the dispersion state of the fibers was good, and the touch was soft.

4:3 and 5 in between

3: there was a portion in which the dispersion state of the fibers was slightly poor, but the feel was soft.

2:1 and 3 in between

1: the dispersion state of the fibers as a whole is very poor, and the touch is rough.

(2) Flexibility:

ten healthy adult males and adult females were evaluated as one of the evaluators in total, and the evaluation was performed as described in the following 5 to 1 by the sensory evaluation, and the most evaluated was regarded as the appearance quality. The preferable level in the present invention is 4 or more.

5: the deformation is softly followed, and the touch is soft.

4:3 and 5 in between

3: the following of the deformation is slightly poor, but the touch is soft.

2:1 and 3 in between

1: after deformation, the sheet will bend and feel stiff.

(3) The rebound feeling is as follows:

5: the core is restored to the original shape after being deformed and feels when being held.

4:3 and 5 in between

3: the core is slightly felt when the core is held, but the core cannot be restored to the original shape after being deformed.

2:1 and 3 in between

1: the core does not return from the deformed state, and the core is not felt when being held.

(4) Fold, sag during bending:

5: even when bent, there was no significant wrinkling or sagging of the sheet.

4:3 and 5 in between

3: after bending, the folds were slightly visible, but there was no sagging of the sheet.

2:1 and 3 in between

1: after bending, the folds were clearly visible and the sheet also sagged.

< expression of chemical substance >

PET: polyethylene terephthalate

PU: polyurethane

MDI:4,4' -diphenylmethane diisocyanate

DMF: n, N-dimethylformamide

PVA: polyvinyl alcohol.

< ultrafine fiber resin >

(1) Polyethylene terephthalate A (PET-A)

Ethylene glycol: petroleum resource source

Terephthalic acid: petroleum resource source

Degree of biomass plasticity: 0 percent

(2) Polyethylene terephthalate B (PET-B)

Ethylene glycol: resource of biomass resource

Terephthalic acid: petroleum resource source

Degree of biomass plasticity: 31 percent of

< polymeric elastomer >

(1) Polycarbonate-based polyurethane A (PU-A)

Polyol: polycarbonate diol (Petroleum resources)

Polyisocyanate: MDI (Diphenyl-methane-diisocyanate)

Chain extension agents: EG

Degree of biomass plasticity: 0 percent of

(2) Polycarbonate-based polyurethane B (PU-B)

Polyol: polycarbonate diol (Biomass resource source)

Polyisocyanate: MDI (Diphenyl-methane-diisocyanate)

Chain extension agent: EG

Degree of biomass plasticity: 38 percent

[ example 1]

(raw cotton)

Polyethylene terephthalate A (PET-A) was used as an island component, polystyrene was used as a sea component, and a sea-island type composite die having 16 islands/hole was used to melt-spin at a spinning temperature of 280 ℃, an island/sea mass ratio of 55/45, a discharge amount of 1.3 g/min/hole, and a spinning speed of 1300 m/min. Then, the fiber was stretched 3.6 times in a spinning oil bath at 90 ℃ and was subjected to crimping treatment using a press-in crimper, and then cut into a length of 51mm, thereby obtaining raw cotton of sea-island type composite fiber in which the average straight fiber diameter of the ultrafine fibers as island components was 3.5 μm.

(interlacing)

Using the raw cotton obtained as described, a laminated web was formed at 3500 cotton threads/cm through carding and cross lapping steps ² The number of the pricking pins is pricked to obtain the pricking pin with the thickness of 4.2mm and the density of 0.20g/cm ³ Interlaced sheets (felts).

(imparting, releasing, compressing Water-soluble resin)

After the entangled sheet was shrunk by hot water at a temperature of 96 ℃, an aqueous solution of PVA having a saponification degree of 88% by mass and a saponification degree of 12% by mass was impregnated, the sheet was pressed at a target adhesion amount of 40% by mass to the fiber component of the solid content, and the PVA was dried for 10 minutes while being transferred by hot air at a temperature of 140 ℃, thereby obtaining a sheet with PVA. Next, the PVA-attached sheet obtained as described above was immersed in trichloroethylene, and squeezing and compression by a mangle (mangle) were performed ten times, whereby the sea component was dissolved and removed and the PVA-attached sheet was compressed, and thereby a kelp-removed PVA sheet in which extra fine fiber bundles to which PVA were added were entangled was obtained.

(imparting of Polymer elastomer)

The compressed sheet of the kelp-removed PVA was immersed in a DMF solution of polyurethane a (PU-a) adjusted to a solid content concentration of 15 mass%, pressed at a target adhesion amount of 50 mass% with respect to the fiber component of the solid content, and solidified in an aqueous solution having a DMF concentration of 30 mass%. Thereafter, PVA and DMF were removed by hot water, and dried for 10 minutes by hot air at a temperature of 110 ℃, thereby obtaining a sheet with polyurethane.

(fluffing)

One side of the sheet with polyurethane was ground with an annular sandpaper of sandpaper type No. 240, and thickness adjustment was performed simultaneously with formation of a raised face, thereby obtaining a raised sheet having a thickness of 2.70 mm.

(dyeing)

The raised sheet was dyed using a liquid flow dyeing machine at a temperature of 120 ℃, and dried using a dryer to obtain artificial leather.

The obtained artificial leather has good surface quality, soft softness and moderate resilience, and has no bending wrinkle or sagging when bent. The results are shown in Table 1.

[ example 2]

(raw cotton)

Raw cotton of sea-island type composite fiber was obtained in the same manner as in example 1.

(interlacing)

Except that the thickness was set to 4.7mm and the density was set to 0.18g/cm ³ Except for this, an entangled sheet (mat) was obtained in the same manner as in example 1.

(addition, dehydration, compression of Water-soluble resin-addition of Polymer elastomer)

A sheet with polyurethane was obtained in the same manner as in example 1.

(fluffing)

A pile sheet was obtained in the same manner as in example 1, except that the thickness was changed to 2.75 mm.

(dyeing)

An artificial leather was obtained in the same manner as in example 1.

The obtained artificial leather has good surface quality, soft softness and moderate rebound feeling, and has no bending wrinkle or sagging when bent. The results are shown in Table 1.

[ example 3]

(raw cotton)

(interlacing)

Except that the thickness was set to 2.6mm and the density was set to 0.19g/cm ³ Except for this, an entangled sheet (mat) was obtained in the same manner as in example 1.

(imparting, releasing, compressing Water-soluble resin-imparting Polymer elastomer)

A sheet with polyurethane was obtained in the same manner as in example 1.

(fluffing)

A napped sheet was obtained in the same manner as in example 1, except that the thickness was 1.60 mm.

(dyeing)

Artificial leather was obtained in the same manner as in example 1.

[ example 4]

(raw cotton)

Polyethylene terephthalate B (PET-B) was used as an island component, polystyrene was used as a sea component, and a die for sea-island composite having 16 island/hole islands was used to perform melt spinning at a spinning temperature of 285 ℃, an island/sea mass ratio of 80/20, a discharge amount of 1.2 g/min/hole, and a spinning speed of 1100 m/min. Then, the fiber was stretched 2.8 times in a spinning oil solution bath at 90 ℃, and was subjected to crimping treatment using a press-in crimper, and then cut into a length of 51mm, thereby obtaining a sea-island type conjugate fiber raw cotton of ultrafine fibers as an island component, the average straight fiber diameter of which was 5.0 μm.

(interlacing)

Except that the thickness was set to 2.3mm and the density was set to 0.25g/cm ³ Except for the above, an entangled sheet (mat) was obtained in the same manner as in example 1)。

(imparting, releasing, compressing Water-soluble resin)

A kelp-removed PVA sheet was obtained in the same manner as in example 1, except that the target adhering amount was 30 mass%.

(addition of Polymer elastomer)

The compressed sheet of the kelp-removed PVA was immersed in a DMF solution of polyurethane a (PU-a) adjusted to a solid content concentration of 12 mass%, pressed at a target attachment amount of 30 mass% with respect to the solid fiber component, and polyurethane was coagulated in an aqueous solution having a DMF concentration of 30 mass%. Thereafter, PVA and DMF were removed by hot water, and dried for 10 minutes by hot air at a temperature of 110 ℃, thereby obtaining a sheet with polyurethane.

(fluffing)

A napped sheet was obtained in the same manner as in example 1, except that the thickness was 1.35 mm.

(dyeing)

Artificial leather was obtained in the same manner as in example 1.

[ example 5]

(raw cotton)

Raw cotton of sea-island type composite fiber was obtained in the same manner as in example 4.

(interlacing)

Except that the thickness was set to 2.4mm and the density was set to 0.24g/cm ³ Except for this, an entangled sheet (mat) was obtained in the same manner as in example 1.

(imparting, releasing, compressing Water-soluble resin)

A sheet of a kelp-removed PVA was obtained in the same manner as in example 4.

(imparting of Polymer elastomer)

A sheet with polyurethane was obtained in the same manner as in example 4, except that polyurethane B (PU-B) was used.

(fluffing)

A pile sheet was obtained in the same manner as in example 1, except that the thickness was set to 1.45 mm.

(dyeing)

An artificial leather was obtained in the same manner as in example 1.

[ example 6]

(raw cotton)

(interlacing)

A sheet with polyurethane was obtained in the same manner as in example 4.

(fluffing)

A napped sheet was obtained in the same manner as in example 1, except that the thickness was 1.30 mm.

(dyeing)

Artificial leather was obtained in the same manner as in example 1.

[ example 7]

(raw cotton)

Polyethylene terephthalate A (PET-A) was used as an island component, polystyrene was used as a sea component, and melt spinning was carried out at a spinning temperature of 280 ℃, an island/sea mass ratio of 60/40, a discharge amount of 1.1 g/min/hole, and a spinning speed of 1300m/min using a sea-island composite die having 200 islands/hole. Then, the fiber was stretched 2.8 times in a spinning oil solution bath at 90 ℃, and was subjected to crimping treatment using a press-in crimper, and then cut into a length of 51mm, thereby obtaining a sea-island type conjugate fiber raw cotton of ultrafine fibers as an island component, the average straight fiber diameter of which was 0.7 μm.

(interlacing)

Except that the thickness was set to 2.0mm and the density was set to 0.22g/cm ³ Except for this, an entangled sheet (mat) was obtained in the same manner as in example 1.

A sheet with polyurethane was obtained in the same manner as in example 4.

(fluffing)

A pile sheet was obtained in the same manner as in example 1, except that the thickness was set to 1.15 mm.

(dyeing)

Artificial leather was obtained in the same manner as in example 1.

[ Table 1]

Comparative example 1

(raw cotton. Intertwining)

An entangled sheet (mat) was obtained in the same manner as in example 1.

(imparting, releasing, compressing Water-soluble resin)

A kelp-removed PVA sheet was obtained in the same manner as in example 1, except that the PVA was dried for 30 minutes while inhibiting migration of PVA by hot air at a temperature of 100 ℃, the PVA-attached sheet was immersed in trichloroethylene, and sea components were removed without carrying out the padding and compression treatment by a padding machine.

(imparting to Polymer elastomer-dyeing)

An artificial leather was obtained in the same manner as in example 1.

The obtained artificial leather has poor surface quality, poor flexibility, little springback feeling, and remarkable bending wrinkles and sagging at the time of bending. The results are shown in Table 2.

Comparative example 2

(raw cotton. Intertwining)

An entangled sheet (mat) was obtained in the same manner as in example 1.

(imparting, releasing, compressing Water-soluble resin)

A sheet of a degranulated PVA was obtained in the same manner as in example 1, except that the PVA was dried for 10 minutes while being transferred by hot air at a temperature of 140 ℃, the sheet with the PVA was immersed in trichloroethylene, and the sea component was removed without carrying out the padding and compression treatment by the padding machine.

(imparting to Polymer elastomer-dyeing)

An artificial leather was obtained in the same manner as in example 1.

The obtained artificial leather had poor surface quality, poor flexibility and a springback feeling, but was remarkably wrinkled or sagged when bent. The results are shown in Table 2.

Comparative example 3

(imparting of raw Cotton-Polymer elastomer)

A sheet with polyurethane was obtained in the same manner as in example 1.

(fluffing)

A napped sheet having a thickness of 1.45mm was obtained in the same manner as in example 1, except that the sheet with polyurethane was cut into halves in the thickness direction and the opposite side to the half-cut side was napped.

(dyeing)

Artificial leather was obtained in the same manner as in example 1.

The obtained artificial leather had good surface quality, but was inferior in flexibility and less in springback feeling, and was slightly wrinkled at bending. The results are shown in Table 2.

Comparative example 4

(raw cotton. Intertwining)

An entangled sheet (mat) was obtained in the same manner as in example 4.

(imparting, releasing, compressing Water-soluble resin)

A kelp-removed PVA sheet was obtained in the same manner as in example 4, except that the PVA was dried for 30 minutes while inhibiting migration of PVA by hot air at a temperature of 100 ℃, the PVA-attached sheet was immersed in trichloroethylene, and sea components were removed without carrying out the padding and compression treatment by a padding machine.

(imparting to Polymer elastomer-dyeing)

An artificial leather was obtained in the same manner as in example 4.

The obtained artificial leather has poor surface quality, poor flexibility, little springback feeling, and remarkable bending wrinkle or sagging at the time of bending. The results are shown in Table 2.

[ Table 2]

	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
					Ultra-fine fiber resin	PET-A	PET-A	PET-A	PET-B
High-molecular elastomer	PU-A	PU-A	PU-A	PU-A
					Average single fiber diameter [ mu ] m of ultrafine fibers]	3.5	3.5	3.5	5.0
F _A /F _B [-]	1.10	1.06	0.90	1.15
					F _C /F _B [-]	1.13	1.10	1.50	1.10
P _A /P _B [-]	1.15	0.92	0.87	1.10
					P _C /P _B [-]	1.10	0.95	1.45	1.05
Density of the whole artificial leather [ g/cm ] ³ ]	0.31	0.30	0.31	0.35
					Thickness of artificial leather [ mm ]]	2.82	2.88	1.35	1.50
Degree of bioplastic of nonwoven [% ]]	0	0	0	31
					Biomass plastics content of the polymer elastomer [% ]]	0	0	0	0
Degree of biomass plasticity of artificial leather [% ]]	0	0	0	23
					Surface grade	3	3	4	3
Flexibility of the film	3	3	3	3
					Sense of rebound	3	4	3	3
Folding, sagging or sagging during bending	2	2	3	2

[ example 8]

(raw cotton. Dyeing)

Artificial leather was obtained in the same manner as in example 1.

(formation of resin layer)

The spin coating method was repeated three times on the raised surface of the sheet obtained in the above step, and a polyurethane resin layer consisting of three discontinuous layers was formed on the surface to obtain an artificial leather. In addition, the resin layer portions on the surface are scattered in island shapes, and the resin layers are intermittently present.

The obtained artificial leather has good surface quality, soft softness and moderate rebound feeling, and has no bending wrinkle or sagging when bent. The results are shown in Table 3.

[ example 9]

(raw cotton. Dyeing)

An artificial leather was obtained in the same manner as in example 4.

(formation of resin layer)

An artificial leather was obtained in the same manner as in example 8.

Comparative example 5

(raw cotton. Dyeing)

An artificial leather was obtained in the same manner as in comparative example 1.

(formation of resin layer)

An artificial leather was obtained in the same manner as in example 8.

The obtained artificial leather has poor surface quality, poor flexibility, little springback feeling, and remarkable bending wrinkle or sagging at the time of bending. The results are shown in Table 3.

[ Table 3]

	Example 8	Example 9	Comparative example 5
				Ultra-fine fiber resin	PET-A	PET-B	PET-A
High-molecular elastomer	PU-A	PU-A	PU-A
				Thickness of resin layer [ mu ] m]	0.10	0.10	0.10
Average single fiber diameter [ mu ] m of ultrafine fibers]	3.5	5.0	3.5
				F _A /F _B [-]	0.86	0.78	1.20
F _C /F _B [-]	0.84	0.76	1.20
				Density of the whole artificial leather [ g/cm ] ³ ]	0.35	0.41	0.36
Thickness of artificial leather [ mm ]]	2.70	1.30	2.72
				Degree of bioplastic of nonwoven [% ]]	0	31	0
Polymer bulletDegree of biomass plasticity of the body [% ]]	0	0	0
				Degree of biomass plastics of resin layer [% ]]	0	0	0
Degree of biomass plasticity of artificial leather [% ]]	0	21	0
				Surface grade	5	4	3
Flexibility of the film	4	5	3
				Sense of resilience	5	4	3
Folding, sagging or sagging during bending	4	5	2

[ description of symbols ]

1: raising layer

2: resin layer

11: artificial leather

A. D: wherein the layer on one surface side

B. E: layer at the center in the thickness direction

C. F: layer on the other surface side

Claims

1. An artificial leather comprising a nonwoven fabric comprising microfine fibers having an average single fiber diameter of 0.1 to 10 μm and a polymeric elastomer as structural elements, wherein the artificial leather satisfies the following formulae (a) and (b),

0.5≦F _A /F _B ＜1···(a)

0.5≦F _C /F _B ＜1···(b)

2. The artificial leather according to claim 1, wherein the artificial leather has at least one raised layer formed by raising.

3. The artificial leather according to claim 1 or 2, wherein the artificial leather is further provided with at least one resin layer.

4. The artificial leather according to claim 3, wherein the resin layer is intermittently formed in the surface of the artificial leather.

5. The artificial leather according to claim 1 or 2, wherein the artificial leather further satisfies the following formula (c), and formula (d),

0.6≦P _A /P _B ＜1···(c)

0.6≦P _C /P _B ＜1···(d)

here, P _A 、P _B 、P _C The densities (g/cm) of the elastic polymer in the layer on one surface side of the artificial leather divided into three equal parts in the thickness direction ³ ) Density (g/cm) of the elastic polymer in the layer at the center in the thickness direction ³ ) The density (g/cm) of the elastic polymer in the layer on the other surface side ³ )。

6. The artificial leather according to any one of claims 1 to 5, wherein the density of the whole artificial leather is 0.2g/cm ³ Above and 0.7g/cm ³ The following.

7. The artificial leather according to any one of claims 1 to 6, wherein a thickness of the artificial leather is 0.8mm or more and 4.0mm or less.