Artificial leather and manufacturing method thereof, and miscellaneous goods

Abstract

To provide an artificial leather that is excellent in strength and abrasion resistance regardless of high thickness and can express excellent plush grade on both surfaces.SOLUTION: An artificial leather comprises: an entangled fiber assembly including a nonwoven fabric formed of ultra fine fibers and a woven or knitted fabric; and elastomer. The artificial leather has nap on both surfaces. The entangled fiber assembly is formed by laminating the nonwoven fabric, the woven or knitted fabric, and the nonwoven fabric in this order. The nonwoven fabrics have thickness of 1.0 mm or more and 2.0 mm or less, respectively. Ratio of thickness of one nonwoven fabric to thickness of the other nonwoven fabric falls within range of 3 / 5 to 5 / 3. Cross section of the artificial leather satisfies following formula 1: 0.5≤R1 / R2≤0.9...(formula 1), where R1, R2 are area percentage (%) of the elastomer at a part closest to a nap side of a region that is equally divided into three parts in a thickness direction after eliminating the nap part of the nonwoven fabric part, and area percentage (%) of elastomer at a part closest to the woven or knitted fabric side, respectively.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an artificial leather and a method for producing the same. [Background technology]

[0002] Artificial leather with a natural leather look, which is made of a fiber-entangled structure containing a nonwoven fabric made primarily of ultrafine fibers as a component and a polymeric elastomer, has superior characteristics compared to natural leather, such as high durability and uniform quality. There are a wide variety of artificial leathers, and they are diversified according to their applications, such as suede-like leather with a brushed surface and grain-like leather with a polymeric elastomer applied to the surface layer.

[0003] Suede-like artificial leather is highly regarded for its high-quality, uniform texture and luster due to the raised surface, and is used in a wide range of applications, including automotive interior materials, furniture, miscellaneous goods, clothing, etc. In particular, when used for hats, bags, straps, etc., strength, comfort, and a satisfying touch are required, and artificial leather with raised surfaces on both sides is commonly used.

[0004] However, in such cases, the back surfaces of artificial leathers designed for single-sided use must be glued together by sewing or using glue, which poses potential issues such as increased processing costs and reduced peel strength. Therefore, from the perspective of reducing processing costs and preventing a decrease in peel strength, there is a demand for artificial leathers that are a single piece and have excellent nap quality, strength, and a rich touch on both surfaces. Various proposals have been made for artificial leathers that have nap quality on both surfaces and excellent strength and abrasion resistance.

[0005] For example, Patent Document 1 proposes a suede-like artificial leather having raised ultrafine fibers on both surfaces, the suede-like artificial leather comprising a nonwoven fabric structure comprising nonwoven fabric layers formed by interlacing ultrafine fibers and woven or knitted fabrics between the nonwoven fabric layers, with a rubber-like elastic material interposed in the interstitial spaces of the structure, the two nonwoven fabric layers being made of ultrafine fibers of different fiber materials and laminated with the woven or knitted fabrics to form a laminate structure, the ultrafine fibers of the nonwoven fabric layers on both sides of the woven or knitted fabrics being mutually mixed near the woven or knitted fabrics but not substantially mixed in the surface layer of the fiber structure, and the suede-like artificial leather having raised ultrafine fibers of different fiber materials on both surfaces. It is stated that this provides a suede-like artificial leather with excellent reversible properties, with both surfaces being raised and dyed in different colors. Patent Document 2 proposes an artificial leather made of a fiber-entangled structure formed by entanglement of a woven fabric with a nonwoven fabric made of ultrafine fibers and a polymeric elastomer, with both surfaces having napped surfaces, the napped surface closest to the woven fabric having an average nap length of 50 μm to 150 μm and a CV value of 30% or less, and the distance between the woven fabric and the napped surface closest to the woven fabric in the thickness direction cross section of the artificial leather being greater than half the thickness of the woven fabric. This artificial leather reduces fiber shedding due to friction or rubbing, and is less susceptible to deterioration in appearance and physical properties, especially when washed in a washing machine. Furthermore, it is described that this artificial leather has an elegant appearance and soft feel similar to natural leather and is widely used in a variety of applications, from furniture, chairs, and vehicle interior materials to clothing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Unexamined Patent Publication No. 57-11280 [Patent Document 2] Japanese Patent Publication No. 2022-44226 Summary of the Invention [Problem to be solved by the invention]

[0007] In the technology disclosed in Patent Document 1, woven or knitted fabrics are present inside the artificial leather, and some of the ultrafine fibers in the nonwoven fabric layer adjacent to the woven or knitted fabric penetrate into the structure of the woven or knitted fabric and are integrally entangled with each other, and both surfaces of the artificial leather have nap-raising quality, making it possible to obtain an artificial leather with excellent strength. However, even with such an artificial leather, if the thickness of the artificial leather is increased, the entanglement between the nonwoven fabric layer and the woven or knitted fabric becomes insufficient, resulting in reduced abrasion resistance, making it difficult to obtain an artificial leather with a solid feel in thickness.

[0008] Furthermore, in the technology disclosed in Patent Document 2, a nonwoven fabric and a woven fabric of an artificial leather are entangled and integrated, and the nap length on the surface closer to the woven fabric is made uniform within a specific range, thereby making it possible to obtain artificial leather that has nap quality on both surfaces of the artificial leather and has excellent strength and abrasion resistance. However, in such artificial leather, the nap length on the surface with nap closer to the woven fabric is short, and the difference in nap length on both surfaces causes a difference in quality between the two surfaces, so there remains a problem in obtaining artificial leather with sufficiently excellent nap quality on both surfaces.

[0009] The present invention has been made in consideration of the above circumstances, and its object is to provide an artificial leather that has excellent strength and abrasion resistance even when it is thick, and that can exhibit excellent nap quality on both surfaces. [Means for solving the problem]

[0010] As a result of extensive investigations by the present inventors to achieve the above-mentioned object, it has become possible to obtain an artificial leather that is excellent in strength and abrasion resistance even when thick, and that can exhibit excellent nap quality on both surfaces, by setting the thicknesses of the nonwoven fabrics and their ratios in a fiber-entangled structure in an artificial leather, i.e., a fiber-entangled structure in which a nonwoven fabric made of ultrafine fibers, a woven or knitted fabric, and a nonwoven fabric made of ultrafine fibers are laminated in this order, and the ratio of the area proportions of the polymer elastomer present on the nap-raised portion side of the nonwoven fabric and on the woven or knitted fabric side in the cross section of the artificial leather within specific ranges. The present invention has been completed based on these findings, and the following inventions are provided according to the present invention. [1] A nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less; Woven and knitted fabrics, A fiber-entangled body comprising: A polymeric elastomer; An artificial leather having both surfaces with raised nap, The fiber-entangled body is formed by laminating the nonwoven fabric, the woven or knitted fabric, and the nonwoven fabric in this order, The nonwoven fabrics each have a thickness of 1.0 mm or more and 2.0 mm or less, and the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric is within a range of 3 / 5 to 5 / 3; In the cross section of the artificial leather, the following formula 1 is satisfied: artificial leather 0.5≦R1 / R2≦0.9 (Formula 1) where: R1: The area ratio (%) of the polymeric elastomer in the most napped part of the cross section of the artificial leather, divided into three equal parts in the thickness direction, excluding the napped part of the nonwoven fabric part R2: The area ratio (%) of the polymeric elastomer in the part closest to the woven or knitted fabric in the cross section of the artificial leather, excluding the napped part from the nonwoven fabric part, divided into three equal parts in the thickness direction. [2] The artificial leather according to [1], wherein the area ratio of the polymeric elastomer in the entire cross section of the artificial leather is 5.0% or more and 15.0% or less. [3] The artificial leather according to [1] or [2], wherein the area ratio of the polymeric elastomer measured from the surface of the artificial leather is 0.01% or more and 3.00% or less on both surfaces. [4] The artificial leather according to any one of [1] to [3], wherein the average nap length of at least one surface of the artificial leather is 200 μm or more and 600 μm or less. [5] The artificial leather according to any one of [1] to [4], wherein a discontinuous resin portion is formed on at least one surface of the artificial leather. [6] A nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less; Woven and knitted fabrics, A fiber-entangled body comprising: A polymeric elastomer; A method for producing artificial leather having raised nap on both surfaces, a step of entangling a woven or knitted fabric on one side of nonwoven fabric α made of ultrafine fiber-developing fibers to form an entangled sheet; A step of forming a nonwoven fabric β made of ultrafine fiber development type fibers; a step of laminating the entangled sheet and the nonwoven fabric β so that the woven or knitted fabric is sandwiched between the nonwoven fabric α and the nonwoven fabric β, and entangled and integrated by needle punching to form a precursor sheet; applying a water-soluble resin to the precursor sheet to form a water-soluble resin-coated sheet; generating ultrafine fibers from the ultrafine fiber-developing fibers in the water-soluble resin-coated sheet to form an ultrafine fiber sheet; a step of providing a polymeric elastomer to the ultrafine fiber sheet to form a polymeric elastomer-coated sheet; grinding both surfaces of the polymeric elastomer-attached sheet to form a raised sheet; and In the step of forming the precursor sheet, The entangled sheet and the nonwoven fabric β before being entangled and integrated satisfy the following formula 2: The entanglement and integration satisfies the following formula 3: Artificial leather manufacturing method 0.30≦V β1 / V A ≦0.80 (Formula 2) 0.30≦D α / D β ≦0.70 (Equation 3) where: V A : Apparent density (g / cm) of the entangled sheet before entanglement and integration 3 ) V β1 : Apparent density (g / cm) of the nonwoven fabric β before the entanglement and integration 3 ) D A : Needle punch density (numbers / cm) punched from the entangled sheet side 2 ) D β : Needle punch density (counts / cm) punched from the β side of the nonwoven fabric 2 ) [7] V A and V β1 However, both are 0.01g / cm 3 More than 0.30g / cm 3 The method for producing an artificial leather according to [6] above, which is as follows: [8] A method for producing an artificial leather according to [6] or [7], wherein in the step of forming the water-soluble resin-coated sheet, the water-soluble resin is added in an amount of 0.1 mass % or more and 30.0 mass % or less relative to the mass of the precursor sheet. [9] The method for producing an artificial leather according to any one of [6] to [8], wherein in the step of forming the polymeric elastomer-added sheet, the polymeric elastomer is added in an amount of 10% by mass or more and 40% by mass or less relative to the mass of the water-soluble resin-added sheet.

[10] A method for producing an artificial leather according to any one of [6] to [9], comprising a step of applying a resin to the surface of the raised sheet to form a discontinuous resin portion on at least one surface of the artificial leather.

[11] Miscellaneous goods including the artificial leather according to any one of [1] to [5]. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain an artificial leather that is excellent in strength and abrasion resistance even when it is thick, and that can exhibit excellent nap quality (elegant surface appearance, fullness, and suppleness) on both surfaces. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional conceptual diagram illustrating a method for measuring the average nap length of an artificial leather according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional conceptual diagram illustrating a method for measuring the thickness of a nonwoven fabric in an artificial leather according to one embodiment of the present invention. [Figure 3]FIG. 3 is a conceptual plan view illustrating the form of discontinuous resin portions formed on at least one surface of an artificial leather according to one embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional conceptual diagram illustrating the form of discontinuous resin portions formed on at least one surface of an artificial leather according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The artificial leather of the present invention has a fiber-entangled body including a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less, and a woven or knitted fabric, and a polymeric elastomer, and has both surfaces having napped surfaces, wherein the fiber-entangled body is formed by laminating the nonwoven fabric, the woven or knitted fabric, and the nonwoven fabric in this order, and the nonwoven fabrics each have a thickness of 1.0 mm or more and 2.0 mm or less, and the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric is within a range of 3 / 5 to 5 / 3, and the cross section of the artificial leather satisfies the following formula 1: 0.5≦R1 / R2≦0.9 (Formula 1) Here, R1 is the area ratio (%) of the polymer elastomer in the part closest to the napped side of the region obtained by dividing the cross section of the artificial leather into three equal parts in the thickness direction of the region obtained by excluding the napped part from the nonwoven fabric part, and R2 is the area ratio (%) of the polymer elastomer in the part closest to the woven or knitted fabric side of the region obtained by dividing the cross section of the artificial leather into three equal parts in the thickness direction of the region obtained by excluding the napped part from the nonwoven fabric part. These components will be described in detail below, but the present invention is not limited to the scope described below as long as it does not deviate from the gist of the invention.

[0014] [Fiber entanglement] [Nonwoven fabric] The fiber-entangled body of the artificial leather of the present invention includes a nonwoven fabric made of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less.

[0015] The ultrafine fibers of this nonwoven fabric are preferably composed primarily of melt-spinnable thermoplastic resins such as polyesters (e.g., polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and polylactic acid); polyamides (e.g., polyamide 6, polyamide 66, and polyamide 12); polyolefins (e.g., acrylic, polyethylene, and polypropylene); polyphenylene sulfide (PPS) and thermoplastic cellulose. Among these, polyester-based resins are preferred from the viewpoints of strength, dimensional stability, and light resistance. In the present invention, the term "major component" refers to a component whose content accounts for 50% by mass or more of the constituent elements. For example, "the main component of the ultrafine fibers is polyethylene terephthalate" means that 50% by mass or more of the components of the ultrafine fibers is polyethylene terephthalate.

[0016] Examples of the polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polylactic acid, as well as polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, and polyethylene-1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate. Among these, polyethylene terephthalate, which is the most widely used, or a polyester copolymer containing primarily ethylene terephthalate units is preferably used. In the present invention, "polyester copolymer containing primarily ethylene terephthalate units" refers to a polyester copolymer containing 80 mol% or more of ethylene terephthalate units, whose copolymerization component is isophthalic acid or bisphenol A.

[0017] Furthermore, the polyester-based resin may be a single polyester or a blend of two or more different polyesters. When a blend of two or more different polyesters is used, the difference in intrinsic viscosity (IV value) of the polyesters used is preferably 0.50 or less, and more preferably 0.30 or less, from the viewpoint of compatibility between the two or more components.

[0018] In the present invention, the intrinsic viscosity is calculated by the following method. (1) Dissolve 0.8 g of sample polymer in 10 mL of orthochlorophenol. (2) Relative viscosity η measured using an Ostwald viscometer at 25°C r Calculate using the formula below and round off to the third decimal place. η r =η / η0=(t×d) / (t0×d0) Intrinsic viscosity (IV value) = 0.0242η r +0.2634 where η is the viscosity of the polymer solution, η0 is the viscosity of orthochlorophenol, t is the drop time of the solution (seconds), and d is the density of the solution (g / cm 3 ), t0 is the fall time of orthochlorophenol (seconds), and d0 is the density of orthochlorophenol (g / cm 3 ) respectively.

[0019] From the viewpoint of processing operability, the cross-sectional shape of the ultrafine fibers is preferably round (a cross-sectional shape that is a perfect circle); however, other shapes can also be used depending on the desired properties, such as oval, capsule-like, polygonal (including shapes with rounded corners) shapes, fan-shaped, cross-shaped, hollow, Y-shaped, T-shaped, and U-shaped cross-sectional shapes.

[0020] The average single fiber diameter of the ultrafine fibers is 0.01 μm or more and 10.00 μm or less. By making the average single fiber diameter of the ultrafine fibers 0.01 μm or more, preferably 1.00 μm or more, excellent effects are achieved in color development after dyeing, light fastness and friction fastness, and stability during spinning. On the other hand, by making the average single fiber diameter of the ultrafine fibers 10.00 μm or less, preferably 5.00 μm or less, artificial leather with a smooth touch and fine surface quality can be obtained.

[0021] In the present invention, the average single fiber diameter of ultrafine fibers is calculated by taking an SEM image of the cross section of the artificial leather using a scanning electron microscope (SEM, for example, Model VHX-D500 / D510 manufactured by Keyence Corporation), randomly selecting 10 circular or nearly circular elliptical ultrafine fibers, measuring the single fiber diameter, calculating the arithmetic average of the 10 fibers, and rounding off to two decimal places. However, when ultrafine fibers with a modified cross section are used, the diameter of the single fiber is determined by first measuring the cross-sectional area of ​​the single fiber and calculating the diameter when the cross section is considered to be circular.

[0022] To the resin forming the ultrafine fibers, various additives may be added according to various purposes, within the scope of not impairing the object of the present invention, such as black pigments described below, chromatic fine particle oxide pigments such as "iron oxyhydroxide and cobalt aluminate," inorganic particles such as titanium oxide particles, lubricants, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, antibacterial agents, etc.

[0023] In the artificial leather of the present invention, for example, in order to achieve both deep and uniform color development, it is also preferable that the ultrafine fibers contain a black pigment. Examples of black pigments that can be used include carbon-based black pigments such as carbon black and graphite, and oxide-based black pigments such as triiron tetroxide, copper, and chromium composite oxides. Carbon black is particularly preferred because it is easy to obtain a black pigment with a small particle size and has excellent dispersibility in polymers.

[0024] When the ultrafine fibers contain a black pigment, the average particle size of the black pigment is preferably 0.05 μm or more and 0.20 μm or less. The average particle size of the black pigment here refers to the average particle size of the black pigment in a state where it is present in the ultrafine fibers, and is generally referred to as the secondary particle size.

[0025] By setting the average particle size of the black pigment to preferably 0.05 μm or more, and more preferably 0.07 μm or more, the black pigment is easily retained inside the ultrafine fibers, thereby preventing the pigment from falling off from the ultrafine fibers. This results in an artificial leather with superior abrasion resistance. Furthermore, by setting the average particle size of the black pigment to preferably 0.20 μm or less, more preferably 0.18 μm or less, and even more preferably 0.16 μm or less, it is possible to prevent the pigment from being exposed to the surface of the ultrafine fibers, and to achieve excellent stability during spinning and yarn strength, resulting in an artificial leather with excellent abrasion resistance and strength.

[0026] Furthermore, when the ultrafine fibers contain a black pigment, the coefficient of variation (CV) of the particle size of the black pigment is preferably 75% or less. When the coefficient of variation (CV) of the particle size of the black pigment is 75% or less, preferably 65% ​​or less, more preferably 60% or less, even more preferably 55% or less, and most preferably 50% or less, the particle size distribution becomes narrow, and problems such as exposure of the pigment on the surface of the ultrafine fibers, detachment of small particles from the surface, poor spinning due to significant particle aggregation, and a significant decrease in yarn strength are suppressed. There is no particular lower limit for the coefficient of variation of the particle size in the present invention, but from the viewpoint of spinning operability and production costs, it is preferably 0.1% or more.

[0027] In the present invention, the average particle size and coefficient of variation (CV) of the black pigment are calculated by the following method. (1) The artificial leather is immersed in a solution containing dimethylformamide or the like to remove the polymeric elastomer and extract ultrafine fibers. (2) Ultrathin sections of 5 to 10 μm thick are prepared from the collected ultrafine fibers in the cross-sectional direction perpendicular to the longitudinal direction of the ultrafine fibers. For example, an ultramicrotome "MT6000" manufactured by Sorvall can be used to prepare these ultrathin sections. (3) Observe the cross section of the fiber in the ultrathin section at 10,000x magnification using a transmission electron microscope (TEM, for example, the "H7700" model manufactured by Hitachi High-Technologies Corporation). (4) Using image analysis software (such as "WinROOF" manufactured by Mitani Corporation), measure the circle-equivalent diameter of 20 black pigment particle diameters contained within a 2.3 μm × 2.3 μm field of view of the observed image. If there are fewer than 20 black pigment particles contained within the 2.3 μm × 2.3 μm field of view, measure the circle-equivalent diameter of all black pigment particle diameters present. (5) Calculate the average value (arithmetic mean) and coefficient of variation (CV) for the particle diameters measured at 20 points. In the present invention, the coefficient of variation is calculated using the following formula: Coefficient of variation of particle size (%) = (standard deviation of particle size) / (arithmetic mean of particle size) × 100 (formula).

[0028] Furthermore, when the ultrafine fibers contain a black pigment, the content of the black pigment in the resin forming the ultrafine fibers is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 2.0% by mass or more and 5.0% by mass or less, based on the mass of the ultrafine fibers. By setting the pigment content to 0.1% by mass or more, preferably 1.0% by mass or more, more preferably 2.0% by mass or more, even more preferably 2.5% by mass or more, and most preferably 3.0% by mass or more, artificial leather can be obtained that has excellent dark color development. By setting the pigment content to 5.0% by mass or less, preferably 4.5% by mass or less, and more preferably 4.0% by mass or less, artificial leather can be obtained that has improved physical properties such as strength and elongation.

[0029] In the present invention, the content of the black pigment contained in the resin forming the ultrafine fibers is calculated by the following method. (1) The artificial leather is immersed in a solution containing dimethylformamide or the like to remove the polymeric elastomer and extract ultrafine fibers. (2) The resin in the collected ultrafine fibers is dissolved using a mixture of phenol and tetrachloroethane, and only the black pigment is extracted. (3) Perform evolved gas analysis on the extracted black pigment and create a calibration curve for evolved gas from the black pigment. (4) After the artificial leather is de-dyed, the polymeric elastomer is extracted using dimethylformamide or the like to leave only the ultrafine fibers, and the ultrafine fibers are then collected. (5) Perform evolved gas analysis on the collected ultrafine fibers, and calculate the proportion of black pigment contained in the ultrafine fibers from the detected intensity of evolved gas derived from the black pigment and the calibration curve created in (3).

[0030] The artificial leather of the present invention contains a nonwoven fabric made of the ultrafine fibers as a constituent element, which allows the surface to be raised to have a uniform and elegant appearance and texture.

[0031] Nonwoven fabrics come in two forms: long-fiber nonwoven fabrics made primarily of filaments, and short-fiber nonwoven fabrics made primarily of fibers 100 mm or less. When short-fiber nonwoven fabrics are used, more fibers can be oriented in the thickness direction of the artificial leather than when long-fiber nonwoven fabrics are used, and by raising the fabric, the surface of the artificial leather can be made to have a high density and a good feel to the touch.

[0032] When using a short-fiber nonwoven fabric, the fiber length of the ultrafine fibers is preferably 25 mm or more and 95 mm or less. By setting the fiber length to 95 mm or less, more preferably 85 mm or less, and even more preferably 75 mm or less, the artificial leather will have an excellent texture and a dense, smooth surface. On the other hand, by setting the fiber length to 25 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more, the artificial leather will have excellent abrasion resistance.

[0033] [Woven and knitted fabrics] In the artificial leather of the present invention, for the purpose of imparting strength and shape stability, a woven or knitted fabric as described below is inserted into the nonwoven fabric, and the fabrics are entangled and integrated to form a fiber-entangled body. In this way, the fiber-entangled body is formed by laminating the nonwoven fabric, the woven or knitted fabric, and the nonwoven fabric in this order, and an artificial leather having excellent nap quality on both surfaces can be obtained.

[0034] As the type of fiber constituting the woven or knitted fabric of the artificial leather of the present invention, it is preferable to use filament yarn, spun yarn, or a composite yarn made of a filament yarn and a spun yarn, and from the viewpoint of durability, particularly mechanical strength, it is more preferable to use a multifilament whose main component is a polyester resin or a polyamide resin.

[0035] The average single fiber diameter of the fibers constituting the woven or knitted fabric is preferably 1.0 μm or more and 50.0 μm or less. By setting the average single fiber diameter of the fibers constituting the woven or knitted fabric to preferably 50.0 μm or less, more preferably 15.0 μm or less, and even more preferably 13.0 μm or less, an artificial leather with excellent flexibility can be obtained. On the other hand, by setting the average single fiber diameter of the fibers constituting the woven or knitted fabric to preferably 1.0 μm or more, more preferably 8.0 μm or more, and even more preferably 9.0 μm or more, an artificial leather with higher dimensional stability can be obtained.

[0036] In the present invention, the average single fiber diameter of the fibers constituting the woven or knitted fabric is calculated by taking an SEM image of the cross section of the artificial leather using a scanning electron microscope (SEM, for example, the VHX-D500 / D510 model manufactured by Keyence Corporation), randomly selecting 10 fibers constituting the woven or knitted fabric, measuring the single fiber diameter of the fibers, calculating the arithmetic average of the 10 fibers, and rounding off to one decimal place.

[0037] When the fibers constituting the woven or knitted fabric are multifilaments, the total fineness of the multifilaments is preferably 30 dtex or more and 170 dtex or less, as measured by "8.3.1 Correct fineness b) Method B (simplified method)" of "8.3 Fineness" in JIS L1013:2010 "Testing methods for chemical fiber filament yarns."

[0038] When the total fineness of the yarns constituting the woven or knitted fabric is 170 dtex or less, the artificial leather has excellent flexibility. On the other hand, when the total fineness is 30 dtex or more, the artificial leather not only has higher dimensional stability, but also has high surface quality because the fibers constituting the woven or knitted fabric are less likely to be exposed on the surface of the artificial leather when the nonwoven fabric and the woven or knitted fabric are entangled and integrated by needle punching or the like. In this case, it is preferable that the total fineness of the warp and weft multifilaments is the same.

[0039] Furthermore, the twist number of the yarns constituting the woven or knitted fabric is preferably 1000 T / m or more and 4000 T / m or less. A twist number of preferably 4000 T / m or less, more preferably 3500 T / m or less, and even more preferably 3000 T / m or less results in an artificial leather with excellent flexibility. On the other hand, a twist number of preferably 1000 T / m or more, more preferably 1500 T / m or more, and even more preferably 2000 T / m or more can prevent damage to the fibers constituting the woven or knitted fabric when the nonwoven fabric and the woven or knitted fabric are entangled and integrated by needle punching or the like, resulting in an artificial leather with excellent mechanical strength.

[0040] In the present invention, the term "woven or knitted fabric" refers collectively to woven fabrics and knitted fabrics, and their weaves are not particularly limited. For example, in the case of woven fabrics, plain weave, twill weave, satin weave, etc. are listed, with plain weave being preferred from the viewpoint of cost. In addition, in the case of knitted fabrics, circular knit, tricot, raschel, etc. are listed.

[0041] Furthermore, when a woven fabric is used in the present invention, the weave density of the woven fabric is preferably adjusted so that both the warp and weft threads in the artificial leather are 40 threads / 2.54 cm or more and 200 threads / 2.54 cm or less. Having a weave density of 40 threads / 2.54 cm or more for the woven fabric inside the artificial leather allows for an artificial leather with excellent shape stability. On the other hand, having a weave density of 200 threads / 2.54 cm or less for the woven / knitted fabric inside the artificial leather allows for a softer texture.

[0042] [Polymer elastic material] The substrate of the artificial leather of the present invention further comprises a polymeric elastomer in addition to the fiber-entangled structure containing the nonwoven fabric and the woven or knitted fabric.

[0043] Examples of the polymeric elastomer include polyurethane, polyurea, polyurethane-polyurea, polyacrylic, etc. Since the polymeric elastomer plays the role of a binder that holds the ultrafine fibers contained in the artificial leather, in consideration of the soft texture of the artificial leather of the present invention, it is preferable that the polymeric elastomer used be polyurethane.

[0044] The polyurethane is obtained by the reaction of a polymer diol, an organic diisocyanate, and a chain extender, and either an organic solvent-based polyurethane, which is used in a dissolved state in an organic solvent, or a water-dispersed polyurethane, which is used in a dispersed state in water, can be used.

[0045] When the polymeric elastomer is polyurethane, the polymer diol may be, for example, a polycarbonate-based diol, a polyester-based diol, a polyether-based diol, a silicone-based diol, or a fluorine-based diol, or a copolymer of these may be used. Among these, from the viewpoints of hydrolysis resistance and abrasion resistance, it is preferable to use a polycarbonate-based diol.

[0046] Examples of polycarbonate-based diols include diols obtained by transesterification of alkylene glycol with carbonate ester, or by reaction of phosgene or chloroformate with alkylene glycol.

[0047] Examples of alkylene glycols used in polycarbonate-based diols include linear alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol, branched alkylene glycols 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, both polycarbonate-based diols obtained from a single alkylene glycol and copolymer polycarbonate-based diols obtained from two or more alkylene glycols can be used.

[0048] The polyester-based diols include diols obtained by condensing various low-molecular-weight polyols with polybasic acids.

[0049] Examples of low molecular weight polyols used in polyester diols include one or more selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-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, cyclohexane-1,4-dimethanol, and adducts of various alkylene oxides with bisphenol A.

[0050] Examples of the polybasic acid used in the polyester diol include one or more selected from the group consisting of 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.

[0051] Furthermore, examples of polyether diols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols obtained by combining these.

[0052] When the polymeric elastomer is polyurethane, the number-average molecular weight of the polymer diol is preferably in the range of 500 to 4000, provided that the molecular weight of the polyurethane elastomer is constant. By setting the number-average molecular weight to preferably 500 or more, more preferably 1500 or more, it is possible to prevent the artificial leather from becoming hard. Furthermore, by setting the number-average molecular weight to preferably 4000 or less, more preferably 3000 or less, it is possible to maintain the strength of the polyurethane.

[0053] From the viewpoint of reducing the environmental load, the polyurethane preferably contains a component derived from a biomass resource, and it is also preferable to use a component derived from a biomass resource in a polymer diol, for which it is relatively easy to procure raw materials derived from biomass resources.

[0054] Next, when the polymeric elastomer is polyurethane, examples of the organic diisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, and aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, and these can also be used in combination.

[0055] When the elastomer is polyurethane, the chain extender may preferably be an amine-based chain extender such as ethylenediamine or methylenebisaniline, or a diol-based chain extender such as ethylene glycol. Alternatively, a polyamine obtained by reacting polyisocyanate with water may also be used as the chain extender.

[0056] Furthermore, when the polymeric elastomer is polyurethane, a crosslinking agent can be used in combination to improve water resistance, abrasion resistance, hydrolysis resistance, etc. The crosslinking agent may be an external crosslinking agent added to polyurethane as a third component, or an internal crosslinking agent that pre-introduces reactive points that form a crosslinked structure within the polyurethane molecular structure. From the viewpoint of forming crosslinked points more uniformly within the polyurethane molecular structure and reducing loss of flexibility, it is preferable to use an internal crosslinking agent.

[0057] As the crosslinking agent, a compound having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, or the like can be used.

[0058] In the present invention, the mass proportion of the polymer elastomer in the artificial leather (hereinafter sometimes abbreviated as "mass proportion of polymer elastomer") is preferably 15.0 mass% or more and 40.0 mass% or less. By setting the lower limit of the mass proportion of the polymer elastomer to preferably 15.0 mass% or more, more preferably 20.0 mass% or more, the bonds between fibers by the polymer elastomer can be strengthened, resulting in an artificial leather with high abrasion resistance. On the other hand, by setting the upper limit of the mass proportion of the polymer elastomer to preferably 40.0 mass% or less, more preferably 30.0 mass% or less, the artificial leather can be thick yet highly flexible.

[0059] The mass proportion of the polymeric elastomer in the artificial leather is measured and calculated by the following method. (1) Three test pieces measuring 20 cm in length and 20 cm in width are randomly taken from the artificial leather, and the mass of each test piece is measured. (2) The test piece is immersed in a solution containing dimethylformamide or the like to remove the polymeric elastomer and collect the ultrafine fibers. (3) Measure the mass of the collected ultrafine fibers, and calculate the mass ratio of the polymer elastomer in the test piece using the following formula: Mass ratio of polymer elastomer to test piece (%) = {(test piece mass) - (ultrafine fiber mass)} / (test piece mass) x 100 (4) For each of the three test pieces, calculate the mass percentage (%) of the polymer elastomer in each test piece, and round off the arithmetic mean value (%) to one decimal place to determine the mass percentage of the polymer elastomer in the artificial leather.

[0060] Furthermore, the polymeric elastomer may contain various additives depending on the purpose, such as "inorganic or oxide-based" pigments, "phosphorus-based, halogen-based, or inorganic" flame retardants, "phenol-based, sulfur-based, or phosphorus-based" antioxidants, "benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based, or oxalic acid anilide-based" ultraviolet absorbers, "hindered amine-based or benzoate-based" light stabilizers, hydrolysis-resistant stabilizers such as polycarbodiimides, plasticizers, antistatic agents, surfactants, coagulation adjusters, and dyes.

[0061] In the artificial leather of the present invention, for example, in order to achieve both deep and uniform color development, it is also preferable that the polymeric elastomer contains a black pigment. This black pigment can be a carbon-based black pigment such as carbon black or graphite, or an oxide-based black pigment such as triiron tetroxide, copper, and chromium composite oxide. Carbon black is particularly preferred because it is easy to obtain a black pigment with a small particle size and has excellent dispersibility in polymers.

[0062] When the polymeric elastomer contains a black pigment, the average particle size of the black pigment is more preferably 0.05 μm or more and 0.20 μm or less. The average particle size of the black pigment here refers to the average particle size of the black pigment in a state where it is present in the polymeric elastomer, and is generally referred to as the secondary particle size.

[0063] By setting the average particle size of the black pigment to preferably 0.05 μm or more, and more preferably 0.07 μm or more, the black pigment is more easily retained within the polymeric elastomer, thereby preventing the pigment from falling off from the polymeric elastomer. This results in an artificial leather with superior abrasion resistance. Furthermore, by setting the average particle size of the black pigment to preferably 0.20 μm or less, and more preferably 0.18 μm or less, and more preferably 0.16 μm or less, the pigment can be more easily dispersed during impregnation with the polymeric elastomer, resulting in an artificial leather with minimal hue variation.

[0064] Furthermore, when the polymeric elastomer contains a black pigment, the coefficient of variation (CV) of the particle size of the black pigment is preferably 75% or less. When the coefficient of variation (CV) of the particle size of the black pigment is 75% or less, preferably 65% ​​or less, more preferably 60% or less, even more preferably 55% or less, and most preferably 50% or less, the particle size distribution becomes narrow, and the detachment of small particles from the polymeric elastomer surface and the precipitation of significantly aggregated particles in the impregnation tank are suppressed. Note that, although there is no particular lower limit for the coefficient of variation of the particle size in the present invention, from the viewpoint of operability when impregnating the polymeric elastomer, a value of 0.1% or more is preferred.

[0065] In the present invention, the average particle size and coefficient of variation (CV) of the black pigment contained in the polymeric elastomer are calculated by the following method. (1) Ultrathin sections of 5 to 10 μm thick are prepared from the artificial leather in the cross-sectional direction perpendicular to its longitudinal direction. (2) The cross section of the polymeric elastomer in the ultrathin slice is observed at 10,000x magnification using a transmission electron microscope (TEM, for example, the "H7700" model manufactured by Hitachi High-Technologies Corporation). (3) Using image analysis software (such as "WinROOF" manufactured by Mitani Corporation), measure the circle-equivalent diameter of 20 black pigment particle diameters contained within a 2.3 μm × 2.3 μm field of view of the observed image. If there are fewer than 20 black pigment particles contained within the 2.3 μm × 2.3 μm field of view, measure the circle-equivalent diameter of all black pigment particle diameters present. (4) Calculate the average value (arithmetic mean) and coefficient of variation (CV) for the particle diameters measured at 20 points. In the present invention, the coefficient of variation is calculated using the following formula: Coefficient of variation of particle size (%) = (standard deviation of particle size) / (arithmetic mean of particle size) × 100 (formula).

[0066] Furthermore, when the polymeric elastomer contains a black pigment, the content of the black pigment in the polymeric elastomer is preferably 0.01% by mass or more and 5.0% by mass or less, based on the mass of the polymeric elastomer. By setting the pigment mass percentage to preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1.0% by mass or more, the artificial leather will have excellent dark color development. On the other hand, by setting the pigment mass percentage to 5.0% by mass or less, preferably 4.5% by mass or less, and more preferably 4.0% by mass or less, the artificial leather will have excellent physical properties, such as strength.

[0067] In the present invention, the content of the black pigment contained in the polymeric elastomer is calculated by the following method. (1) The artificial leather is immersed in a mixture of phenol and tetrachloroethane to dissolve the ultrafine fibers and extract a polymeric elastomer. (2) The collected polymeric elastomer is dissolved in dimethylformamide or the like, and only the black pigment (b) is extracted. (3) Perform evolved gas analysis on the extracted black pigment and create a calibration curve for evolved gas from the black pigment. (4) The polymeric elastomer contained in the artificial leather is dissolved in dimethylformamide or the like, and then the dimethylformamide or the like is removed, thereby solidifying the polymeric elastomer again. (5) The polymer elastomer obtained in (4) is subjected to evolved gas analysis, and the content of the black pigment contained in the polymer elastomer that constitutes the artificial leather is calculated from the detected intensity of evolved gas derived from the black pigment and the calibration curve prepared in (3).

[0068] [Artificial leather] The artificial leather of the present invention is an artificial leather comprising the fiber-entangled body and the polymeric elastomer, both surfaces of which have naps. From the viewpoint of design, the nap configuration on the napped surface preferably has a nap length and directional flexibility sufficient to leave a mark when a finger is traced, i.e., the direction of the naps changes, leaving a so-called finger mark. More specifically, the average nap length on at least one surface of the artificial leather is preferably 200 μm or more and 600 μm or less. By setting the lower limit of the average nap length to preferably 200 μm or more, more preferably 250 μm, the surface smoothness of the artificial leather can be improved, resulting in an artificial leather with excellent touch. On the other hand, by setting the upper limit of the average nap length to preferably 600 μm or less, more preferably 500 μm or less, the artificial leather can be made to have excellent abrasion resistance while maintaining a uniform and dense surface quality. The average nap length of the artificial leather can be adjusted by the grinding conditions in the "step of forming a napped sheet" in the manufacturing method of the artificial leather described below.

[0069] In the present invention, the average nap length is measured and calculated by the following method. (1) Using a lint brush or the like, raise the nap of the artificial leather and prepare a thin section 1 mm thick in the cross-sectional direction perpendicular to the longitudinal direction of the artificial leather. (2) A cross section of the artificial leather is photographed at 90x magnification using a scanning electron microscope (SEM, for example, Keyence Corporation's "VHX-D500 / D510"). (3) In the SEM image, the bottom surface of the artificial leather (L in Fig. 1) is identified according to the schematic diagram of the cross section of the artificial leather shown in Fig. 1. B ) parallel to the line (L in Figure 1) A ) and draw perpendicular lines at 200 μm intervals. Here, the bottom surface of the artificial leather refers to the surface that is parallel to the horizontal surface when the artificial leather is placed on a horizontal surface with the wrinkles smoothed out. (4) Points X1 to X2 are placed on the boundary line (L0) between the raised part and the base part (described later). 10 Mark. (5) Points X1~X 10 Draw a perpendicular line from each point Y1 to Y2 in the direction of the napped portion and intersect with the tip of the napped layer. 10 Mark. (6) Find the distance Z1 between point X1 and point Y1, and then Z 10 The average value (arithmetic mean) of these values ​​is rounded off to the first decimal place to obtain the average nap length of the artificial leather.

[0070] The artificial leather of the present invention is obtained by impregnating a fiber-entangled body with a polymeric elastomer, as shown in Fig. 1, and has, on both surfaces of the fiber-entangled body, a piled portion 2 having a certain pile length and the remaining portion, a base portion 3. The base portion includes the woven or knitted fabric 4.

[0071] The fiber-entangled body of the artificial leather is formed by laminating a nonwoven fabric, a woven or knitted fabric, and another nonwoven fabric in this order, and each of the nonwoven fabrics has a thickness of 1.0 mm or more and 2.0 mm or less.

[0072] When the lower limit of the thickness of the nonwoven fabric is 1.0 mm or more, preferably 1.2 mm or more, and more preferably 1.4 mm or more, an artificial leather having sufficient thickness and a rich feel can be obtained. On the other hand, when the upper limit of the thickness of the nonwoven fabric is 2.0 mm or less, preferably 1.8 mm or less, and more preferably 1.6 mm or less, an artificial leather can be obtained that can uniformly conform to complex shapes during molding.

[0073] In the present invention, the thickness of the nonwoven fabric is measured and calculated by the following method. (1) Using a lint brush or the like, raise the nap of the artificial leather and prepare a thin section 1 mm thick in the cross-sectional direction perpendicular to the longitudinal direction of the artificial leather. (2) A cross section of the artificial leather is photographed at 90x magnification using a scanning electron microscope (SEM, for example, Keyence Corporation's "VHX-D500 / D510"). (3) In the SEM image, the bottom surface of the artificial leather (L in Fig. 2) is identified according to the schematic diagram of the cross section of the artificial leather shown in Fig. 2. B ) parallel to the line (L in Figure 2) A ) and draw perpendicular lines at 200 μm intervals. (4) Among the intersections of the perpendicular line drawn in (3) and the woven or knitted fabric, the points S1 to S2 closest to the raised layer side of the nonwoven fabric where the thickness is to be measured are 10 Mark. (5) Points S1~S 10 Draw a perpendicular line in the direction of the raised part of the nonwoven fabric whose thickness is to be measured from each point T1 to T2. 10 Mark. (6) Let U1 be the distance between points S1 and T1, and similarly, U 10 The average value (arithmetic mean) is calculated by rounding off to one decimal place, and the resulting value is calculated as the thickness of the nonwoven fabric.

[0074] Furthermore, the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric is within the range of 3 / 5 to 5 / 3. If the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric is less than 3 / 5 to 5 / 3, a difference in quality will occur between the two surfaces due to differences in nap height on both surfaces, making it impossible to obtain artificial leather with excellent nap height on both surfaces.

[0075] On the other hand, the thickness of the woven or knitted fabric for the artificial leather is preferably 0.10 mm or more and 0.40 mm or less.

[0076] By setting the lower limit of the thickness of the woven or knitted fabric to preferably 0.10 mm or more, more preferably 0.15 mm or more, it is possible to impart superior shape stability to the artificial leather, while by setting the upper limit of the thickness of the woven or knitted fabric to preferably 0.40 mm or less, more preferably 0.30 mm or less, it is possible to provide an artificial leather with a softer feel.

[0077] In the present invention, the thickness of the woven or knitted fabric is the thickness remaining after subtracting the thickness of the nonwoven fabric from the thickness of the artificial leather.

[0078] The nonwoven fabric in the artificial leather of the present invention satisfies the following formula 1 in the cross section of the artificial leather: 0.5≦R1 / R2≦0.9 (Formula 1) Here, R1 is the area ratio (%) of the polymeric elastomer in the part closest to the napped side of the cross section of the artificial leather, obtained by dividing the area of ​​the nonwoven fabric excluding the napped part into three equal parts in the thickness direction, and R2 is the area ratio (%) of the polymeric elastomer in the part closest to the woven or knitted fabric of the cross section of the artificial leather, obtained by dividing the area of ​​the nonwoven fabric excluding the napped part into three equal parts in the thickness direction. In addition, in the present invention, the "cross section of the artificial leather" refers to a cross section perpendicular to the surface direction of the artificial leather.

[0079] By setting the lower limit of R1 / R2 to 0.5 or more, preferably 0.6 or more, the bonds between the fibers near the surface of the artificial leather due to the polymer elastomer can be strengthened, resulting in an artificial leather with high abrasion resistance.On the other hand, by setting the upper limit of R1 / R2 to 0.9 or less, preferably 0.8 or less, the proportion of the polymer elastomer that penetrates into the interior of the artificial leather increases, resulting in an artificial leather with a supple feel.

[0080] R1 / R2 in the artificial leather of the present invention can be adjusted by the needle punching conditions in the <step of forming the entangled sheet and nonwoven fabric β> in the method for producing an artificial leather described below.

[0081] Next, in the present invention, the area ratio of the polymer elastomer in the entire cross section of the artificial leather is preferably 5.0% or more and less than 15.0%. When the area ratio of the polymer elastomer in the cross section of the artificial leather (hereinafter sometimes abbreviated as "area ratio of the polymer elastomer in the cross section") is preferably 5.0% or more, more preferably 7.0% or more, and even more preferably 9.0% or more, the polymer elastomer is sufficiently bonded between the fibers, resulting in an artificial leather with good strength and abrasion resistance. On the other hand, when the area ratio of the polymer elastomer in the cross section is preferably less than 15.0%, more preferably 14.0% or less, and even more preferably 13.0% or less, the artificial leather has excellent flexibility.

[0082] In the present invention, R1, R2 and the area ratio of the polymeric elastomer in the entire cross section of the artificial leather are calculated by the following method. (1) Randomly take test pieces measuring 0.5 cm in length and 1.0 cm in width from the artificial leather, and embed the internal space in epoxy resin. (2) The resin-embedded specimen is cut parallel to the thickness direction using a microtome. (3) The cut specimen is left to stand in saturated ruthenium tetroxide vapor for 4 hours, which causes the polymeric elastomer in the cross section of the artificial leather to be electronically dyed. (4) The cross section of the artificial leather is coated with 1 nm of osmium atoms to make it conductive. (5) The cross section of the artificial leather is observed at 500x magnification using a field emission scanning electron microscope (e.g., JEOL Ltd.'s "JSM-7800F Prime"). R1 ​​is calculated from 10 randomly taken SEM images of the most napped portion of the nonwoven fabric portion of the cross section of the artificial leather, obtained by dividing the area excluding the napped portion of the nonwoven fabric portion into three equal parts in the thickness direction. R2 is calculated from 10 randomly taken SEM images of the most napped portion of the nonwoven fabric portion of the cross section of the artificial leather, obtained by dividing the area excluding the napped portion of the nonwoven fabric portion into three equal parts in the thickness direction. Furthermore, the area ratio of the polymeric elastomer to the entire cross section of the artificial leather is calculated from 10 randomly taken SEM images of the cross section of the artificial leather. (6) The obtained SEM images are binarized using the image analysis software "ImageJ" or the like in the following manner, and R1, R 2、 And calculate the area ratio (%) of polymer elastomer in the entire cross section of the artificial leather. (i) Filter the SEM image. The processing conditions are as follows: "Hand pass filtering" Filter large structures down to 40pixels Filter small structures up to 3pixels Suppress stipes: None Tolerance of direction: 5% Autoscale after filtering: Yes Saturate image when autoscaling: Yes Filter processing count: 1 "Median filtering" Radius: 4.0 Filter processing count: 1 (ii) Binarization is performed using the MaxEntropy method, and the black parts in the binarized SEM image are identified as polymeric elastomers. (iii) The obtained binarized image (1280 × 960 pixels) is divided into 32 × 32 pixel sections (1200 sections in this case), and the area percentage (%) of the polymer elastomer exposed in the cross section of each section is calculated by dividing the total area of ​​each polymer elastomer distributed within each section by the area of ​​each section using the Analyze Particle function of ImageJ (conditions: Size = 0-infinity, Circularity = 0.00-1.00). (iv) Read the number of pixels on the x and y axes of the target image, specify the partition size in pixel size, find the number of divisions on the x and y axes, and calculate the area ratio of the polymer elastomer within each divided area. The area ratio (%) of the polymer elastomer in the entire cross section of the artificial leather is the value obtained by averaging the area ratio (%) of the polymer elastomer for all partitions and rounding to one decimal place.

[0083] Regarding R1, R2, and R1 / R2, R1, R2, and R1 / R2 are calculated for each of the two nonwoven fabric portions in the cross section of the artificial leather, and the smaller of the two R1 / R2 values ​​calculated for each nonwoven fabric portion is adopted as the result.

[0084] In addition, the artificial leather of the present invention preferably has an area ratio of the polymeric elastomer on both surfaces of the artificial leather of 0.01% to 3.00%.

[0085] For both surfaces of the artificial leather, the area ratio of the polymer elastomer measured from the surface (hereinafter sometimes abbreviated as "area ratio of the polymer elastomer on both surfaces") is preferably 0.01% or more, more preferably 0.05% or more, and even more preferably 0.10% or more. This allows the ultrafine fibers present in the napped portion to be firmly held by the polymer elastomer at the boundary between the napped portion (napped portion) and the non-napped portion (substrate portion) of the artificial leather, resulting in an artificial leather with excellent abrasion resistance on both surfaces. On the other hand, if the area ratio of the polymer elastomer on both surfaces is preferably 3.00% or less, more preferably 2.00% or less, and even more preferably 1.00% or less, the artificial leather will have a dense and smooth surface quality and a good feel on both surfaces.

[0086] The area ratio of the polymer elastomer on both surfaces of the artificial leather can be adjusted to fall within the above range by, for example, applying a water-soluble resin and a polymer elastomer within a predetermined range in the <step of forming a water-soluble resin-coated sheet> and the <step of forming a polymer elastomer-coated sheet> of the artificial leather manufacturing method described below, or by grinding both surfaces of the ultrafine fiber sheet under predetermined grinding conditions in the <step of forming a napped sheet>.

[0087] Furthermore, it is preferable that the standard deviation of the area proportion of the polymer elastomer on both surfaces (hereinafter sometimes abbreviated as "standard deviation of the area proportion of the polymer elastomer on both surfaces") is 25% or less. When the standard deviation of the area proportion of the polymer elastomer on the surface of the artificial leather is preferably 25% or less, more preferably 23% or less, and even more preferably 20% or less, the artificial leather will maintain a dense and smooth surface quality at all points on both surfaces of the artificial leather. There is no particular lower limit for the standard deviation of the area proportion of the polymer elastomer on both surfaces in the present invention.

[0088] In the present invention, the area ratio of the polymeric elastomer on both surfaces of the artificial leather and the standard deviation of the area ratio of the polymeric elastomer on both surfaces are calculated by the following method. (1) Randomly take test pieces measuring 0.5 cm in length and 0.5 cm in width from the artificial leather and leave them in saturated ruthenium tetroxide vapor for 4 hours. This allows the polyurethane exposed on the surface of the artificial leather to be electronically dyed. (2) The surface of the artificial leather is coated with 1 nm of osmium atoms to make it conductive. (3) The surface of the artificial leather is observed at 100x magnification using a field emission scanning electron microscope (for example, the JSM-7800F Prime manufactured by JEOL Ltd.), and calculations are performed from 10 SEM images taken randomly on the surface of the artificial leather. (4) The obtained SEM image is binarized using the image analysis software "ImageJ" or the like in the following manner, and the area ratio of the polymer elastomer on the surface of the artificial leather is calculated. (i) Filter the SEM image. The processing conditions are as follows: Bilateral Filter Fije Plugin Bilateral Filter spatial radius:3 range radius:50 Filter processing times: 5 times (ii) Binarization is performed using the MaxEntropy method, and the black parts in the binarized SEM image are identified as polymeric elastomers. (iii) The obtained binarized image (2560 × 1920 pixels) is divided into 32 × 32 pixel sections (4800 sections in this case), and the area percentage (%) of the polymeric elastomer exposed on the surface of each section is calculated by dividing the total area of ​​each polymeric elastomer distributed within each section by the area of ​​each section using the Analyze Particle function of ImageJ (conditions: Size = 0-infinity, Circularity = 0.00-1.00). (iv) Read the number of pixels on the x and y axes of the target image, specify the partition size in pixel size, find the number of divisions on the x and y axes, and calculate the area percentage of the polymer elastomer within each divided area. The area percentage (%) of the polymer elastomer on the surface of the artificial leather is the average area percentage (%) of the polymer elastomer for all partitions, and its standard deviation is an index of variation from the average value for all partitions.

[0089] An example of image analysis software is the aforementioned image analysis software "ImageJ." However, image analysis software is not limited to "ImageJ" as long as it is image processing software that has the function of calculating the area ratio of specified pixels. Note that "ImageJ" is a commonly used image analysis software developed by the National Institutes of Health. The image processing software "ImageJ" has the function of identifying necessary areas in an imported image and performing pixel analysis.

[0090] Furthermore, the artificial leather of the present invention may have discontinuous resin portions formed on at least one surface of the artificial leather (i.e., at least one of the two napped surfaces). The plurality of discontinuous resin portions dispersed on the surface provides the artificial leather with an elegant surface that is somewhere between a nubuck-like or grain-like surface feel and a suede-like surface feel and feel, and the naps are less likely to fall out, resulting in higher strength. Meanwhile, the discontinuous nature of the resin portions ensures sufficient breathability in the napped portions, which are non-resin portions, and prevents cracking of the resin portions when bent, thereby maintaining good quality and texture.

[0091] In the present invention, "discontinuous resin portions are formed on at least one surface of the artificial leather" refers to a state in which a plurality of resin portions 5 are dispersed and arranged in islands on the napped portion 2, as exemplified in Fig. 3 (plan view) and Fig. 4 (cross-sectional view), and this provides a different effect from that of the polymeric elastomer. Therefore, when the artificial leather is observed from above, it can be seen that both the resin portions 5 and the napped portion 2 are present on the surface of the artificial leather.

[0092] The multiple resin parts 5 scattered like islands may be present in a regular pattern, but it is preferable that the shape and arrangement of the resin parts 5 are random, as this will result in a surface texture closer to that of natural leather.

[0093] Furthermore, the resin portion 5 is preferably composed of multiple layers. When the resin portion 5 is composed of multiple layers, for example, one of the layers can function as an adhesive layer, making the resin portion 5 less likely to peel off and resulting in a highly durable artificial leather. As a result, it can be preferably used in applications requiring greater durability, such as automobile seats and sofas. The adhesive layer need only have the function of bonding the napped portion on the surface of the artificial leather to the other layers constituting the resin portion 5, and its presence between these layers enhances the adhesion between the napped portion on the surface of the artificial leather and the resin portion, resulting in an artificial leather with superior abrasion resistance.

[0094] The resin used for the resin portion 5 is preferably one having elasticity and flexibility, such as polyurethane, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), acrylic resin, etc. Among these, a material containing polyurethane as a main component, specifically a material containing 50% by mass or more of polyurethane, is preferably used in view of the balance between texture and physical properties.

[0095] As described above, polyurethanes include organic solvent-based polyurethanes that are used in a state of being dissolved in an organic solvent, and water-dispersed polyurethanes that are used in a state of being dispersed in water, and either of these can be used in the present invention.

[0096] In the present invention, the polyurethane used in the resin portion 5 is preferably a polyurethane obtained by reacting a polymer diol, an organic diisocyanate, and a chain extender. Furthermore, from the viewpoint of reducing the environmental impact, it is preferable that the polyurethane contains a component derived from a biomass resource. In particular, when a polyurethane is used as the resin used in the resin portion, the component derived from a biomass resource is preferably a polymer diol, which is a constituent of the polyurethane and for which raw materials derived from biomass resources are relatively easy to procure.

[0097] In the case where polyurethane is used as the resin used in the resin portion in the present invention, preferred embodiments of each component constituting this polyurethane will be further described below.

[0098] When polyurethane is used as the resin portion 5, suitable polymer diols include, for example, polycarbonate-based diols, polyester-based diols, polyether-based diols, silicone-based diols, and fluorine-based diols, as well as copolymers of these. Among these, polycarbonate-based diols and polyester-based diols are preferred from the viewpoint of light resistance. Furthermore, polycarbonate-based diols are preferred from the viewpoints of hydrolysis resistance and heat resistance. Furthermore, polyether-based diols or polyester-based diols are preferred for the adhesive layer in terms of adhesion to the napped portions that constitute the surface of the artificial leather.

[0099] Polycarbonate-based diols can be produced by transesterification of alkylene glycol with a carbonate ester, or by reaction of phosgene or a chloroformate with an alkylene glycol.

[0100] Examples of alkylene glycols include linear alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol; branched alkylene glycols 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.

[0101] In the present invention, either a polycarbonate-based diol obtained from a single alkylene glycol or a copolymerized polycarbonate-based diol obtained from two or more types of alkylene glycols can be used.

[0102] When polyurethane is used as the resin for the resin portion 5, suitable organic diisocyanates to be reacted with the polymer diol include, for example, aliphatic polyisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, and aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate and tolylene diisocyanate. These can also be used in combination. Among these, aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate are preferred when durability and heat resistance are important. Aliphatic polyisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferred when light resistance is important. One or more of these organic diisocyanates may be used.

[0103] When polyurethane is used as the resin portion 5, suitable chain extenders 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.

[0104] Furthermore, the resin used to form the resin portion 5 may contain polyester, polyamide, polyolefin, and other elastomer resins, acrylic resins, ethylene-vinyl acetate resins, etc., to the extent that abrasion resistance and texture are not impaired. These resins may also contain various additives, for example, pigments such as carbon black, phosphorus-, halogen-, and inorganic flame retardants, phenol-, sulfur-, and phosphorus-based antioxidants, hindered amine-, benzoate-, and other light stabilizers, hydrolysis-resistant stabilizers such as polycarbodiimides, plasticizers, antistatic agents, surfactants, coagulation adjusters, and dyes.

[0105] The thickness of the resin portion 5 is not particularly limited, but the total thickness of the resin portion 5 on each surface is preferably 1 μm or more and 500 μm or less. When the total thickness is 1 μm or more, more preferably 10 μm or more, and even more preferably 50 μm or more, an artificial leather having discontinuous resin portions formed therein with superior abrasion resistance can be obtained. On the other hand, when the total thickness is 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less, an artificial leather having discontinuous resin portions formed therein with a softer feel can be obtained.

[0106] Furthermore, when the resin portion on each surface is made up of multiple layers, the thickness of each of these layers is preferably 1 μm or more and 200 μm or less.

[0107] In the present invention, the total thickness (μm) of the resin portion is measured as follows. (1) A thin section having a thickness of 1 mm is prepared in the cross-sectional direction perpendicular to the longitudinal direction of the artificial leather having discontinuous resin portions formed thereon. (2) Using a scanning electron microscope (SEM, for example, Keyence Corporation's "VHX-D500 / D510"), photograph 10 different locations of the resin portion of the cross section of the artificial leather in which discontinuous resin portions are formed at 200x magnification. (3) In the SEM image, the direction parallel to the cross section is defined as horizontal, the surface having the discontinuous resin portion to be measured is defined as the top, and the other surface is defined as the bottom. Measure the distance between the horizontal line passing through the highest point of the resin portion and the horizontal line passing through the lowest point of the resin portion. The total thickness (μm) of the resin portion of the artificial leather having discontinuous resin portions formed thereon is the arithmetic average of the 10 measured values, rounded to the first decimal place.

[0108] In the present invention, the weight of the artificial leather is 700 g / m 2 More than 1800g / m 2 The weight of the artificial leather is preferably 700 g / m or less. 2 More preferably, 800 g / m 2 More preferably, 900 g / m 2 By setting the weight of the artificial leather to 1800 g / m or more, it is possible to obtain an artificial leather having a sufficient thickness and a feeling of fullness due to the texture. 2 or less, more preferably 1600 g / m 2 or less, more preferably 1400 g / m 2 By satisfying the above condition, it is possible to obtain artificial leather with a more flexible feel.

[0109] The basis weight of the artificial leather of the present invention is measured in accordance with "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "Testing methods for general nonwoven fabrics," and is measured and calculated as follows. (1) Take three test pieces measuring 30 cm in length and 30 cm in width from the artificial leather. (2) Measure the mass of the test piece in (1). (3) Calculate the mass per unit area of ​​each test piece using the following formula: Mass per unit area (g / m 2) = mass of test piece (g) / area of ​​test piece (m 2 ) (4) The arithmetic mean value of the mass per unit area obtained in (3) (g / m 2 ) is rounded down to the nearest whole number and the resulting value is the basis weight of the artificial leather.

[0110] Furthermore, when the artificial leather of the present invention is subjected to an abrasion resistance test according to "8.19.5 Method E (Martindale method)" of "8.19 Abrasion resistance and discoloration due to friction" of JIS L1096:2010 "Testing methods for woven and knitted fabrics" under a pressure load of 12.0 kPa and 20,000 friction cycles, the loss in mass of the artificial leather after abrasion is preferably 10 mg or less, more preferably 8 mg or less, and even more preferably 6 mg or less, for each surface. A mass loss of 10 mg or less can prevent contamination due to shedding during actual use.

[0111] Regarding the abrasion resistance of the artificial leather, in order to keep the mass loss of the artificial leather within a predetermined range when subjected to a pressing load of 12.0 kPa and 20,000 abrasion cycles, it is preferable to adjust the area ratio of the polymeric elastomer on both surfaces of the artificial leather and the average nap length within the specific ranges described above. By doing so, friction between the naps is reduced, and the mass loss can be suppressed. Furthermore, by setting the thickness of the nonwoven fabric within a specific range, the degree of fiber entanglement is improved, and the mass loss can be suppressed.

[0112] The artificial leather of the present invention preferably has a tensile strength of 100 N / cm or more and 600 N / cm or less in any measurement direction as measured in accordance with "6.3.1 Tensile strength and elongation (ISO method)" of JIS L1913:2010 "Testing methods for general nonwoven fabrics."

[0113] When the tensile strength is preferably 100 N / cm or more, more preferably 200 N / cm or more, the resulting artificial leather has excellent shape stability and durability. When the tensile strength is preferably 600 N / cm or less, more preferably 500 N / cm or less, the resulting artificial leather has flexibility and excellent moldability.

[0114] The artificial leather of the present invention preferably has a bending resistance in the warp or weft direction of 50 mm or more and 250 mm or less, as measured by "8.21.1 Method A (45° cantilever method)" of "8.21 Bending resistance" in JIS L1096:2010 "Testing methods for woven and knitted fabrics." By setting the bending resistance to 50 mm or more, more preferably 60 mm or more, good moldability and molding stability can be ensured. Furthermore, by setting the bending resistance to 250 mm or less, more preferably 200 mm or less, high flexibility can be obtained.

[0115] In the present invention, the vertical direction of the artificial leather refers to the direction in which the artificial leather is raised. The method for determining the direction of the raised treatment can be appropriately adopted depending on the constituent components of the artificial leather, such as visual confirmation when tracing the surface with a finger or SEM photography. That is, the vertical direction is the direction in which the napped fibers can be laid down or raised when tracing the surface with a finger. Furthermore, by taking SEM photographs of the surface of the artificial leather traced with a finger, the vertical direction is determined to be the direction in which the majority of the lying napped fibers are oriented. Meanwhile, the horizontal direction of the artificial leather of the present invention refers to the direction perpendicular to the vertical direction within the plane of the artificial leather.

[0116] [Manufacturing method for artificial leather] The following describes a method for producing the artificial leather of the present invention as described above, specifically, an example of a method for producing an artificial leather having napped surfaces on both sides, the artificial leather comprising a fiber-entangled body including a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm to 10.00 μm, a woven or knitted fabric, and a polymeric elastomer.

[0117] The manufacturing method of the present invention comprises: a step of entangling a woven or knitted fabric on one side of nonwoven fabric α made of ultrafine fiber-developing fibers to form an entangled sheet; A step of forming a nonwoven fabric β made of ultrafine fiber development type fibers; a step of laminating the entangled sheet and the nonwoven fabric β so that the woven or knitted fabric is sandwiched between the nonwoven fabric α and the nonwoven fabric β, and entangled and integrated by needle punching to form a precursor sheet; applying a water-soluble resin to the precursor sheet to form a water-soluble resin-coated sheet; generating ultrafine fibers from the ultrafine fiber-developing fibers in the water-soluble resin-coated sheet to form an ultrafine fiber sheet; a step of providing a polymeric elastomer to the ultrafine fiber sheet to form a polymeric elastomer-coated sheet; grinding both surfaces of the polymeric elastomer-attached sheet to form a raised sheet; Furthermore, in the present invention, In the step of forming the precursor sheet, The entangled sheet and the nonwoven fabric β before being entangled and integrated satisfy the following formula 2: The entanglement and integration satisfies the following formula 3: A method for manufacturing artificial leather 0.30≦V β1 / V A ≦0.80 (Formula 2) 0.30≦D A / D β ≦0.70 (Equation 3) where: V A is the apparent density (g / cm) of the entangled sheet before the entanglement and integration. 3 ) and V β1 is the apparent density (g / cm 3 ) of the nonwoven fabric β before the entanglement and integration 3 ) and D A is the density of needle punches punched from the entangled sheet side (numbers / cm 2 ) and D β is the needle punch density (counts / cm) punched from the β side of the nonwoven fabric 2 )

[0118] Each step will be described in detail below.

[0119] <Process for producing ultrafine fiber-developing fibers> In this process, ultrafine fiber-developing fibers are formed. Ultrafine fiber-developing fibers refer to fibers that can be transformed into ultrafine fibers by the methods described below. Specific examples include islands-in-sea composite fibers, in which thermoplastic resins with different solvent solubilities are used to form a sea portion (easily soluble polymer) and an island portion (slightly soluble polymer), and the sea portion is dissolved and removed using a solvent or the like to form ultrafine fibers from the island portion. Alternatively, peel-type composite fibers are used, in which two thermoplastic resin components with different solvent solubilities are alternately arranged radially or in multiple layers on the fiber cross section, and the components are peeled and split to form ultrafine fibers. Among these, islands-in-sea composite fibers are more preferred from the viewpoints of the texture and surface quality of the artificial leather, and because appropriate voids can be created between the island portions, i.e., between the ultrafine fibers within the fiber bundle, when the sea portion is removed. The resulting ultrafine fiber-developing fibers are sometimes commonly referred to as raw cotton.

[0120] As a method for spinning ultrafine fiber-producing fibers having an islands-in-sea composite structure, a method using a spinneret for islands-in-sea composite fibers and a polymer mutually aligned structure in which sea parts and island parts are mutually aligned and spun is preferred from the viewpoint of obtaining ultrafine fibers with a uniform single fiber diameter.

[0121] For the sea portion of the islands-in-sea type composite fiber, polyethylene, polypropylene, polystyrene, copolymer polyesters copolymerized with sodium sulfoisophthalic acid, polyethylene glycol, etc., and polylactic acid, etc. can be used. From the viewpoints of spinnability, ease of elution, etc., polystyrene and copolymer polyesters are preferably used.

[0122] When the ultrafine fiber-developing fiber is an islands-in-sea type composite fiber, it is preferable to use an islands-in-sea type composite fiber whose island portions have a tensile strength (tensile strength of the ultrafine fibers) of 2.2 cN / dtex or more. By making the tensile strength of the island portions preferably 2.2 cN / dtex or more, more preferably 3.0 cN / dtex or more, and even more preferably 4.0 cN / dtex or more, the abrasion resistance of the artificial leather can be improved and a decrease in friction fastness due to fiber shedding can be suppressed.

[0123] In the present invention, the tensile strength of the island parts of the islands-in-sea type composite fiber (tensile strength of the ultrafine fibers) is calculated by the following method. (1) Ten 20cm long islands-in-the-sea composite fibers are bundled together. (2) After dissolving and removing the sea area from the sample (1), air dry it. (3) According to JIS L1013:2010 "Testing methods for chemical fiber filament yarns", "8.5 Tensile strength and elongation", "8.5.1 Standard time test", the test shall be carried out 10 times (N=10) under the conditions of grip length 5 cm, pulling speed 5 cm / min, and load 2 N. (4) The arithmetic mean value (cN / dtex) of the test results obtained in (3) is rounded off to one decimal place to obtain the tensile strength of the island part of the islands-in-sea type composite fiber, i.e., the tensile strength of the ultrafine fiber.

[0124] <Step of forming entangled sheet and nonwoven fabric β> In this step, for example, the ultrafine fiber development type fibers spun as described above are opened and then formed into a fiber web (nonwoven fabric α) using a cross wrapper or the like, and the woven or knitted fabric is laminated on one side of this and entangled, thereby forming an entangled sheet in which the nonwoven fabric α made of the ultrafine fiber development type fibers and the woven or knitted fabric are entangled and integrated.

[0125] The entanglement method preferably uses needle punching. By using needle punching, a thick entangled sheet can be formed, and an artificial leather having a sufficient thickness and a rich feel can be obtained.

[0126] Similarly to the nonwoven fabric α, the nonwoven fabric β can be obtained by, for example, opening the spun ultrafine fiber-developing fibers and then forming a fiber web using a crosswrapper or the like. The fiber web is preferably subjected to a needle punching process to entangle the ultrafine fiber-developing fibers. The needle punching process can produce a thick nonwoven fabric β, allowing for the production of an artificial leather that is sufficiently thick and has a rich texture.

[0127] The nonwoven fabrics α and β may be in the form of either a short fiber nonwoven fabric or a long fiber nonwoven fabric, as described above. However, if the nonwoven fabric is a short fiber nonwoven fabric, the number of fibers oriented in the thickness direction of the artificial leather will be greater than that of a long fiber nonwoven fabric, and the surface of the artificial leather will have a high degree of density when raised.

[0128] When the nonwoven fabrics α and β are short fiber nonwoven fabrics, the fibers are cut and processed to produce ultrafine fiber-developing fibers of approximately 100 mm or less to obtain raw cotton, which is then opened, laminated, and entangled to obtain short fiber nonwoven fabrics.

[0129] In the present invention, the entangled sheet and the nonwoven fabric β are made to satisfy the following formula 2 at the stage when they are subjected to the <step of forming a precursor sheet> described later. 0.30≦V β1 / V A ≦0.80 (Formula 2) where V A is the apparent density (g / cm) of the entangled sheet before entanglement and integration in the step of forming the precursor sheet. 3 ) and V β1 is the apparent density (g / cm) of the nonwoven fabric β before entanglement and integration in the step of forming the precursor sheet. 3 )

[0130] The above V β1 / V A When the lower limit of V is 0.30 or more, preferably 0.40 or more, the entanglement state of the nonwoven fabrics α and β in the precursor sheet obtained in the <step of forming a precursor sheet> described later, such as the apparent density and the density difference in the thickness direction, can be made approximately equal, and artificial leather having an elegant surface appearance on both surfaces can be obtained. β1 / V A When the upper limit of is 0.80 or less, preferably 0.60 or less, the woven or knitted fabric of the entangled sheet is moderately entangled with the nonwoven fabric β when they are entangled and integrated in the <step of forming a precursor sheet> described below, and an artificial leather with a supple texture can be obtained.

[0131] Furthermore, the V A and Vβ1 However, both are 0.01g / cm 3 More than 0.30g / cm 3 By setting the thickness within the above range, the entangled sheet can be sufficiently entangled with the nonwoven fabric β when they are entangled and integrated in the <step of forming a precursor sheet> described below, and an artificial leather having high abrasion resistance can be obtained.

[0132] The apparent density V of the entangled sheet A and the apparent density V of the nonwoven fabric β β1 is measured and calculated as follows: (1) Three test pieces, each 30 cm long and 30 cm wide, are taken from any location on the entangled sheet or nonwoven fabric β. (2) Measure the mass of the test piece obtained in (1). (3) Calculate the apparent density of each test piece using the following formula: Apparent density (g / cm 3 ) = mass of test piece (g) / {area of ​​test piece (cm 2 ) × thickness of test piece (cm)}. (4) The arithmetic mean value of the apparent density (g / cm) obtained in (3) 3 ) to the third decimal place, calculate to the second decimal place, and V A and V β1 Let's say.

[0133] <Step of forming precursor sheet> In this step, the entangled sheet and the nonwoven fabric β are laminated so that the woven or knitted fabric is sandwiched between the nonwoven fabric α and the nonwoven fabric β, and then entangled and integrated by needle punching to form a precursor sheet.

[0134] In the needle punching process for forming the precursor sheet, the following formula 3 is satisfied: 0.30≦D A / D β ≦0.70 (Equation 3) where D A is the density of needle punches punched from the entangled sheet side (numbers / cm 2) and D β is the needle punch density (counts / cm) punched from the β side of the nonwoven fabric 2 )

[0135] The above D A / D β The lower limit of D is 0.30 or more, preferably 0.40 or more. A / D β When the upper limit of is 0.70 or less, preferably 0.60 or less, the entanglement state of the nonwoven fabrics α and β in the obtained precursor sheet, such as the apparent density and the density difference in the thickness direction, can be made approximately equivalent, and an artificial leather having an elegant surface appearance on both surfaces can be obtained.

[0136] The apparent density of the precursor sheet is 0.15 g / cm 3 More than 0.35g / cm 3 The apparent density is preferably 0.15 g / cm or less. 3 More preferably, 0.20 g / cm 3 By setting the apparent density to 0.35 g / cm or more, a dense feeling can be obtained in the raised nap, and an artificial leather excellent in surface quality and feel can be obtained. 3 or less, more preferably 0.30 g / cm 3 By doing so, sufficient space can be maintained for applying the water-soluble resin and the polymer elastomer in the <step of forming a sheet with water-soluble resin> and <step of forming a sheet with polymer elastomer> described below, and the area ratio of the polymer elastomer in the cross section of the finally obtained artificial leather can be kept within a predetermined range.

[0137] It is also a preferred embodiment that the precursor sheet is subjected to a heat shrinking treatment using hot water or steam in order to improve the denseness of the fibers.

[0138] Here, the apparent density of the precursor sheet is measured and calculated as follows. (1) Three test pieces, each 30 cm long and 30 cm wide, are taken from any location on the precursor sheet. (2) Measure the mass of the test piece obtained in (1). (3) Calculate the apparent density of each test piece using the following formula: Apparent density (g / cm 3 ) = mass of test piece (g) / {area of ​​test piece (cm 2 ) × thickness of test piece (cm) (4) The arithmetic mean value of the apparent density (g / cm) obtained in (3) 3 ) is rounded to two decimal places to obtain the apparent density of the precursor sheet.

[0139] <Step of forming a water-soluble resin-coated sheet> In this step, a water-soluble resin is applied to the precursor sheet to form a water-soluble resin-coated sheet.

[0140] Examples of the water-soluble resin include polyvinyl alcohol, polyethylene oxide, polyacrylamide, resol-type phenolic resin, methylolated urea resin, methylolated melamine resin, carboxymethyl cellulose, etc. This water-soluble resin adheres to the surface of the ultrafine fiber development-promoting fiber contained in the precursor sheet, and serves to prevent strong adhesion between the polymeric elastomer and the ultrafine fiber development-promoting fiber when the polymeric elastomer is imparted as described below.

[0141] The water-soluble resin is preferably added in an amount ranging from 0.1% to 30.0% by mass relative to the mass of the precursor sheet. By adding an amount of the water-soluble resin of preferably 0.1% by mass or more, more preferably 1.0% by mass or more, the presence of the water-soluble resin in the step of adding the polymer elastomer moderately alleviates adhesion between the fibers and the polymer elastomer, while the area ratio of the polymer elastomer in the cross section of the artificial leather is within a predetermined range, resulting in an artificial leather that is thick yet flexible. On the other hand, by adding an amount of the water-soluble resin of preferably 30.0% by mass or less, more preferably 10.0% by mass or less, the mass ratio of the polymer elastomer in the artificial leather is within a predetermined range in the step of adding the polymer elastomer, resulting in an artificial leather with abrasion resistance. The water-soluble resin may be, for example, an aqueous solution of the water-soluble resin, which may be impregnated into the precursor sheet and then dried.

[0142] In this step, it is preferable to include polyethylene glycol in an amount of 0.01% by mass or more and 0.5% by mass or less relative to the mass of the water-soluble resin. By setting the polyethylene glycol content to preferably 0.01% by mass or more, more preferably 0.1% by mass or more, foaming of the water-soluble resin can be suppressed and the preparation time can be shortened when preparing the aqueous solution of the water-soluble resin. On the other hand, by setting the polyethylene glycol content to preferably 0.5% by mass or less, more preferably 0.3% by mass or less, the water-soluble resin can be applied to the precursor sheet in uniform size, and the area ratio of the polymeric elastomer in the cross section of the finally obtained artificial leather can be within a predetermined range.

[0143] <Process for forming ultrafine fiber sheet> In this step, ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less are produced from the ultrafine fiber-producing fibers of the water-soluble resin-coated sheet, to form an ultrafine fiber sheet.

[0144] Ultrafine fibers having an average single fiber diameter within the above range can be produced from the ultrafine fiber-producing fibers of the water-soluble resin-coated sheet by, for example, immersing the water-soluble resin-coated sheet in a solvent. When the ultrafine fiber-producing fibers are islands-in-sea composite fibers, the production can be achieved by, for example, dissolving and removing the sea portion.

[0145] When the ultrafine fiber-developing fiber is an islands-in-sea type composite fiber, the solvent for dissolving and removing the sea portion can be an organic solvent such as toluene or trichloroethylene if the sea portion is made of polyethylene, polypropylene, or polystyrene. Alternatively, an alkaline aqueous solution such as sodium hydroxide can be used if the sea portion is made of copolymer polyester or polylactic acid. Alternatively, hot water (water at 70°C to 99°C) can be used if the sea portion is made of a water-soluble thermoplastic polyvinyl alcohol resin.

[0146] Furthermore, by repeatedly immersing the water-soluble resin-coated sheet in a solvent, squeezing the liquid with a mangle, and compressing the sheet, ultrafine fibers can be efficiently produced from the ultrafine fiber-producing fibers.

[0147] <Step of forming a sheet with polymeric elastomer> In this step, a polymeric elastomer is applied to the ultrafine fiber sheet to form a polymeric elastomer-attached sheet. The polymeric elastomer is preferably applied in an amount of 10% by mass to 40% by mass relative to the mass of the ultrafine fiber sheet. More specifically, the ultrafine fiber sheet is preferably impregnated with a solution of a polymeric elastomer precursor so that the amount applied is 10% by mass to 40% by mass relative to the mass of the ultrafine fiber sheet, and then solidified to form a polymeric elastomer-attached sheet. Here, the polymeric elastomer precursor refers to a precursor (hereinafter sometimes simply referred to as "precursor") that becomes a polymeric elastomer by means of coagulation or solidification, as described below. For example, when the polymeric elastomer is polyurethane, the polyurethane precursor is a mixture of the polyurethane's reactive components, i.e., polymer diol, organic diisocyanate, chain extender, etc.

[0148] Preferred solvents used when adding polyurethane as the polymeric elastomer include N,N'-dimethylformamide, dimethyl sulfoxide, etc. Alternatively, a water-dispersed polyurethane liquid in which polyurethane is dispersed in water as an emulsion may be used.

[0149] In this step, it is preferable to remove the water-soluble resin after the polymer elastomer is applied, from the viewpoint of making the texture of the artificial leather soft. One method for this is to immerse the sheet to which the polymer elastomer has been applied in water heated to 65°C to 95°C (hot water), and then dry the sheet. By immersing the sheet in hot water, it is possible to also remove the solvent, such as N,N'-dimethylformamide or dimethyl sulfoxide, used when applying the polymer elastomer to the ultrafine fiber sheet.

[0150] <Step of forming the raised sheet> In this step, both surfaces of the polymeric elastomer-attached sheet are ground. This allows the surface to be raised and a napped portion to be formed. For this grinding, it is preferable to use a grinding means such as sandpaper or a roll sander.

[0151] To obtain artificial leather with excellent surface quality on both surfaces, the grinding of the polymeric elastomer-attached sheet is preferably carried out in multiple stages, preferably two or more times, more preferably three or more times, for each surface of the polymeric elastomer-attached sheet using a grinding means. Furthermore, it is more preferable to use sandpaper or roll sanders with progressively finer grits in each stage, or at least the same grit size.

[0152] The grit size of the sandpaper or roll sander used to grind the surface of the polymeric elastomer-attached sheet (corresponding to the surface of the artificial leather) is preferably in the range of #100 or more and #320 or less, as specified in JIS R6610:2000 "Grain size of abrasives for abrasive cloths." By using a grit size of the sandpaper or roll sander of preferably #100 or more, more preferably #120 or more, the average nap length of the napped portion of the artificial leather is kept within a preferred range, resulting in an artificial leather with an excellent feel to the touch. On the other hand, by using a grit size of the sandpaper or roll sander of preferably #320 or less, more preferably #240 or less, the artificial leather has a dense feel and a uniform, elegant surface quality.

[0153] When each surface of the polymeric elastomer-attached sheet is ground multiple times with a grinding means, the conveying speed of the ultrafine fiber sheet is preferably 5 m / min or more and 20 m / min or more. By setting the conveying speed of the polymeric elastomer-attached sheet to preferably 5 m / min or more, more preferably 7 m / min or more, it is possible to achieve good productivity while keeping the average nap length within a preferred range. On the other hand, by setting the conveying speed of the polymeric elastomer-attached sheet to preferably 20 m / min or less, more preferably 15 m / min or less, it is possible to suppress the equipment load while keeping the area ratio of the polymeric elastomer measured from the surface of the artificial leather within a preferred range, thereby obtaining artificial leather with a dense and uniform surface quality. Note that the conveying speed of the ultrafine fiber sheet here refers to the speed at which the sheet is fed to a roll or roll sander rotating sandpaper at high speed.

[0154] The grinding speed is preferably 200 m / min or more and 1000 m / min or less. By setting the grinding speed to preferably 200 m / min or more, more preferably 300 m / min or more, it is possible to suppress the load on the equipment while keeping the average nap length within a preferred range and obtain an artificial leather with an excellent touch. On the other hand, by setting the grinding speed to preferably 1000 m / min or less, more preferably 900 m / min or less, it is possible to keep the area ratio of the polymeric elastomer measured from the surface of the artificial leather within a preferred range and obtain an artificial leather with a dense and uniform surface quality. The grinding speed here refers to the peripheral speed calculated from the rotation speed and peripheral length of the sandpaper or roll sander, and can be calculated specifically by the following formula: Grinding speed (m / min) = {sandpaper or roll sander rotation speed (rpm)} x {sandpaper or roll sander circumference (m)} Before grinding, a lubricant such as a silicone emulsion can be applied to the surface of the polymeric elastomer-attached sheet. Also, by applying an antistatic agent to the polymeric elastomer-attached sheet before grinding, grinding dust generated from the artificial leather during grinding is less likely to accumulate on the sandpaper.

[0155] Here, the raised sheet obtained after grinding has a basis weight of 500 g / m 2 More than 1600g / m 2 The basis weight of the raised sheet obtained after grinding is preferably 500 g / m or less. 2 More preferably, 700 g / m 2 More preferably, 900 g / m 2 By doing so, it is possible to obtain an artificial leather that has sufficient thickness and a rich feel. On the other hand, the weight of the raised sheet is preferably 1600 g / m 2 or less, more preferably 1400 g / m 2 More preferably, 1200 g / m or less 2 By satisfying the following conditions, artificial leather with a supple texture can be obtained.

[0156] The basis weight of the raised sheet is measured and calculated as follows. (1) Take three test pieces measuring 30 cm in length and 30 cm in width from any location on the raised sheet. (2) Measure the mass of the test piece obtained in (1). (3) Calculate the mass per unit area of ​​each test piece using the following formula: Mass per unit area (g / m 2 ) = mass of test piece (g) / area of ​​test piece (m 2 ). (4) The arithmetic mean value of the mass per unit area obtained in (3) (g / m 2 ) is rounded down to the nearest whole number and the resulting value is the basis weight of the raised sheet.

[0157] <Post-process> Furthermore, the raised sheet can also be dyed.

[0158] Examples of dyeing methods that can be used include jet dyeing using a jigger dyeing machine or jet dyeing machine, dip dyeing such as thermosol dyeing using a continuous dyeing machine, or printing on napped surfaces using roller printing, screen printing, inkjet printing, sublimation printing, vacuum sublimation printing, etc. Among these, jet dyeing machines are preferred in terms of quality and grade, as they provide a soft texture. Furthermore, various resin finishing processes can be applied after dyeing, if necessary.

[0159] The sheet obtained as described above can be used as artificial leather as it is, but if necessary, the surface can be further processed in various ways to produce artificial leather with excellent design, such as post-processing such as perforation, embossing, laser processing, pinsonic processing, and printing.

[0160] In addition, it is also preferable to apply a resin to the nap-containing surface of the raised sheet so that the area ratio of the resin to the surface is, for example, 10 to 90%, thereby forming a discontinuous resin portion on the surface of the artificial leather as described above, i.e., to have the resin portion and the nap-containing portion substantially coexist on the surface of the artificial leather. By setting the area ratio of the resin to 10% or more, preferably 20% or more, it is possible to obtain artificial leather with better abrasion resistance and a nubuck-like or grain-like surface and feel. On the other hand, by setting the area ratio to 90% or less, preferably 80% or less, it is possible to impart breathability and a nap-like feel similar to that of a suede-like substrate.

[0161] [Application] The artificial leather of the present invention obtained by the above-exemplified production method has an elegant surface appearance on both surfaces, a feeling of fullness and flexibility, as well as high strength and abrasion resistance, and is a material particularly suitable for use in miscellaneous goods and the like.

[0162] Examples of such miscellaneous goods include hats such as fedoras, bowler hats, top hats, pork pie hats, crochet hats, capelins, canotier hats, metro hats, tulip hats, bucket hats, boonie hats, 6-panel caps, trucker caps, jet caps, hunting caps, newsboy caps, marine caps, work caps, trapper caps, knit caps, and berets; gloves such as shorty gloves, demi-gloves, open-finger gloves, fingerless gloves, cut-out gloves, mittens, gauntlets, lace gloves, half-scoop gloves, training gloves, shooting gloves, drawing gloves, hand guards, opera gloves, arm longs, bucket gloves, corset gloves, arm covers, arm warmers, and musk tail gloves; accessories such as belts, scarves, head wraps, hair bands, ear mufflers, and ties; shoe upper trims; bags; and wallets. [Example]

[0163] Next, the artificial leather of the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[0164] [Measurement method and evaluation processing method] The evaluation methods and measurement conditions used in the examples are explained below, except that unless otherwise specified, the measurements of each physical property were carried out according to the above-mentioned methods.

[0165] (1) Average single fiber diameter of ultrafine fibers (μm): In measuring the average single fiber diameter of ultrafine fibers, ultrafine fibers were observed using a scanning electron microscope (SEM) model "VHX-D500 / D510" manufactured by Keyence Corporation, and the average single fiber diameter was calculated.

[0166] (2) Tensile strength of ultrafine fibers (cN / dtex): The tensile strength of the ultrafine fibers was measured using the Tensilon universal material testing machine "RTC-1350A" manufactured by A&D Co., Ltd., and was measured and calculated using the method described above.

[0167] (3) Apparent density V of the entangled sheet A , the apparent density V of the nonwoven fabric β β1 , and the apparent density of the precursor sheet (g / cm 3 ): The apparent density was measured and calculated by the method described above.

[0168] (4) Basis weight of precursor sheet and raised sheet (g / m 2 ): The basis weight of the precursor sheet and the raised sheet is measured and calculated as follows. (i) Take three test pieces measuring 30 cm in length and 30 cm in width from any location on the sheet. (ii) Measure the mass of the test piece obtained in (i). (iii) Calculate the mass per unit area of ​​each test piece using the following formula: Mass per unit area (g / m 2) = mass of test piece (g) / area of ​​test piece (m 2 ) (iv) The arithmetic mean value of the mass per unit area obtained in (iii) (g / m 2 ) is rounded down to the nearest whole number and the value obtained is the basis weight of the sheet.

[0169] (5) Thickness of artificial leather (mm): The thickness of the artificial leather was measured and calculated using a thickness gauge called "Peacock Dial Thickness Gauge H" manufactured by Ozaki Seisakusho Co., Ltd. The thickness of the artificial leather was determined by rounding off the arithmetic mean value of the thickness measured at 10 arbitrary locations on the artificial leather to three decimal places.

[0170] (6) Thickness of the nonwoven fabric part of the artificial leather (mm): To measure the thickness of the nonwoven fabric portion of the artificial leather, a scanning electron microscope (SEM) VHX-D500 / D510 manufactured by Keyence Corporation was used to observe the cross section of the artificial leather, and the thickness of the nonwoven fabric portion of the artificial leather was calculated.

[0171] (7) Artificial leather weight (g / m 2 ): The basis weight of the artificial leather was measured and calculated by the above-mentioned method.

[0172] (8) Area ratio (%) of R1 and R2 in the cross section of the artificial leather and the polymer elastomer in the entire cross section of the artificial leather: In the above measurements, a field emission scanning electron microscope "JSM-7800F Prime" manufactured by JEOL Ltd. was used, and "ImageJ" was used as image analysis software, and measurements and calculations were carried out according to the above methods.

[0173] (9) Mass ratio of polymer elastomer (mass%): The mass proportion of the polymeric elastomer was measured and calculated using dimethylformamide as a solvent.

[0174] (10) Area percentage (%) of polymeric elastomer measured on the surface of artificial leather and its standard deviation (%): In the above measurements, a field emission scanning electron microscope "JSM-7800F Prime" manufactured by JEOL Ltd. was used, and measurements and calculations were carried out using "ImageJ" as image analysis software.

[0175] (11) Average nap length of artificial leather (μm) In measuring the average nap length of the artificial leather, a scanning electron microscope (SEM) VHX-D500 / D510 manufactured by Keyence Corporation was used to observe the cross section of the artificial leather, and the average nap length of the artificial leather was calculated.

[0176] (12) Bending resistance of artificial leather (mm): The bending resistance of the artificial leather was measured and calculated by the above-mentioned method.

[0177] (13) Tensile strength of artificial leather (N / cm): Two 2cm x 20cm test pieces were taken from the artificial leather in any direction, and the tensile strength (N / cm) was measured as specified in "6.3.1 Tensile strength and elongation (ISO method)" of JIS L1913:2010 "General nonwoven fabric test methods." The average of the two pieces was used as the tensile strength of the artificial leather. The measurements were performed using an Instron single-column tabletop testing machine "3343."

[0178] (14) Abrasion resistance of artificial leather (mg): The abrasion resistance test was conducted using a James H. Heal & Co. Ltd. "Model 406" abrasion tester and the same company's "Abrastive Cloth SM25" as the standard friction cloth, and artificial leather with an abrasion loss of 10 mg or less was deemed to have passed.

[0179] (15) Texture of artificial leather: The texture of the artificial leather was evaluated by 20 evaluators, 10 healthy adult males and 10 healthy adult females, according to the following evaluation criteria. The texture of the artificial leather was determined to be the most commonly rated. In the case of a tie, the higher rating was designated as the texture of the artificial leather. The good level of the present invention was designated as A or B. A: When held in the hand, it feels very supple and full, and has a very good texture. B: When held in the hand, it feels supple and substantial, and has a good texture. C: When held in the hand, it feels lacking in flexibility and fullness, and has a poor texture.

[0180] (16) Artificial leather feel: The feel of the artificial leather was evaluated by 20 evaluators, 10 healthy adult males and 10 healthy adult females, who judged the surface of the artificial leather having the napped portion according to the following evaluation criteria, and the feel of the artificial leather was determined to be the most common evaluation. In the case of a tie, the higher evaluation was determined to be the feel of the artificial leather. The good level of the present invention was rated as A or B. A: The surface is extremely smooth to the touch, with no catching whatsoever. B: The surface is smooth to the touch, with a slight grip when stroked. C: The surface feels rough and catchy when stroked. D: The surface feels very rough, with a large amount of friction when you stroke it.

[0181] (17) Surface quality of artificial leather: The surface quality of the artificial leather was evaluated by a total of 20 evaluators, 10 healthy adult males and 10 healthy adult females, who visually judged the following evaluations, and the most common evaluation was taken as the surface quality of the artificial leather. In the case of a tie, the higher evaluation was taken as the surface quality of the artificial leather. The good level of the present invention was rated as A or B. A: Very dense and uniform surface quality. B: Dense and uniform surface quality. C: The surface quality is poorly dense and varies greatly. D: The surface quality is very poorly dense and varies greatly.

[0182] (18) Friction resistance (grade) of artificial leather: A drying test was conducted as specified in "9.1 Friction Tester Type I (Crockmeter) Method" of JIS L0849:2013 "Test Methods for Color Fastness to Friction." The staining gray scale specified in JIS L0805:2005 "Gray Scale for Staining" was used for evaluation, and the color difference was measured and a grade was determined. Furthermore, the grade was determined based on "2) Determination of Discoloration" specified in "10 Determination of Color Fastness" of JIS L0801:2011 "Determination of General Rules for Color Fastness Test Methods," with grades of 4 or higher being considered passing.

[0183] [Example 1] <Process for producing ultrafine fiber-developing fibers> Ultrafine fiber-forming fibers having an island-in-sea composite structure consisting of island and sea components were melt-spun under the following conditions. Island component: Polyethylene terephthalate with an intrinsic viscosity (IV value) of 0.73 Sea component: Polystyrene with an MFR (melt flow rate, measured according to the test method specified in ISO 1133:1997, the same applies below) of 65g / 10min Spinneret: Spinneret for islands-in-sea composite fiber with 16 islands per hole Spinning temperature: 285℃ Island / sea mass ratio: 80 / 20 Discharge rate: 1.2g / min (hole) Spinning speed: 1100m / min.

[0184] The ultrafine fiber-forming fibers were then stretched 2.7 times in a spinning oil bath at 90°C. They were then crimped using a push-type crimper and cut to a length of 51 mm to obtain raw islands-in-sea composite fibers with a single fiber fineness of 4.2 dtex. The ultrafine fibers obtained from these islands-in-sea composite fibers had an average single fiber diameter of 4.40 μm and a tensile strength of 3.7 cN / dtex.

[0185] <Step of forming entangled sheet> The raw cotton of the islands-in-sea composite fiber obtained as described above was used to form a laminated web through carding and cross-wrapping processes. On one side of this laminated web, a plain weave fabric (basis weight 75 g / m) with a warp density of 95 threads / 2.54 cm and a weft density of 76 threads / 2.54 cm was formed using twisted yarns with a twist of 2500 T / m for both the weft and the warp. 2 ) are laminated at 1500 threads / cm 2 The nonwoven fabric α and the woven or knitted fabric are laminated and entangled together, and the apparent density is 0.21 g / cm. 3 An entangled sheet of 1000 .mu.m was obtained.

[0186] <Step of forming nonwoven fabric β> Furthermore, the raw fibers of the islands-in-sea composite fibers obtained in the above-mentioned <Process for producing ultrafine fiber-developing fibers> were used to form a laminated web through carding and cross-lapping processes. 2 The ultrafine fiber-developing fibers are entangled by needle punching at a needle punch density of 0.11 g / cm. 3 A nonwoven fabric β was obtained.

[0187] At this time, the apparent density of the entangled sheet is V A and the apparent density of the nonwoven fabric β: V β3 Ratio of V β3 / V A was 0.52.

[0188] <Step of forming precursor sheet> The entangled sheet and nonwoven fabric β obtained above were then laminated together so that the woven or knitted fabric was sandwiched between the nonwoven fabric α and the nonwoven fabric β, and needle punching was performed under the conditions of Table 1 to obtain a laminate in which the entangled sheet and nonwoven fabric β were entangled and integrated, with an apparent density of 0.24 g / cm 3 , basis weight 1008g / m 2 A precursor sheet having a thickness of 4.20 mm was obtained.

[0189] <Step of forming a water-soluble resin-coated sheet> The precursor sheet obtained as described above was shrunk in hot water at 96°C. The precursor sheet, which had been shrunk in hot water, was then impregnated with an aqueous solution of polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) with a saponification degree of 88%, adjusted to a concentration of 5% by mass. The sheet was then squeezed with a roll and dried for 10 minutes with hot air at 120°C, forming a water-soluble resin-coated sheet containing 6.0% by mass of PVA based on the mass of the precursor sheet, which consisted of a nonwoven fabric and woven / knitted fabric made of ultrafine fiber-developing fibers.

[0190] <Process for forming ultrafine fiber sheet> The resulting water-soluble resin-coated sheet was immersed in trichloroethylene, squeezed with a mangle, and compressed 10 times to dissolve and remove the sea portion of the ultrafine fiber-developing fiber and compress the sheet, resulting in an ultrafine fiber sheet with a thickness of 3.50 mm and an average single fiber diameter of 4.40 μm.

[0191] <Step of forming a polymeric elastomer-coated sheet, step of forming a base sheet> The ultrafine fiber sheet obtained as described above was immersed in a DMF (dimethylformamide) solution of polyurethane, the polymer diol of which was a polycarbonate-based diol and the main component of the elastomer was polyurethane, adjusted to a solids concentration of 11.3%. The ultrafine fiber sheet immersed in the DMF solution of polyurethane was then squeezed with a roll. The sheet was then immersed in a 30% by mass DMF aqueous solution to coagulate the polyurethane. At this point, the amount of elastomer applied relative to the mass of the ultrafine fiber sheet was 18.0% by mass. The PVA and DMF were then removed with hot water at 95°C, and the sheet was dried with hot air at 100°C for 10 minutes. This resulted in a substrate sheet with a thickness of 3.10 mm and a polyurethane mass of 26.2% by mass relative to the mass of the ultrafine fibers.

[0192] <Step of forming the raised sheet> The polymeric elastomer-attached sheet obtained as described above was ground by 0.2 mm on each surface in two stages on both sides using endless sandpaper with a sandpaper count of 180 as the grinding means at a sheet conveying speed of 10 m / min and a grinding speed of 800 m / min, and the sheet was then raised to a thickness of 975 g / m2 with an average single fiber diameter of 4.40 μm. 2 A raised sheet having a thickness of 2.70 mm was obtained.

[0193] <Dyeing process of the raised sheet> The raised sheet is dyed in a liquid flow dyeing machine using black dye. * The dyed sheet was dyed at 120°C using a recipe prepared so that the value was 22, and then reduction washed to obtain a dyed sheet. The sheet was then dried in a pin tenter at 100°C for 7 minutes to obtain artificial leather with a thickness of 3.10 mm and a mass proportion of polymer elastomer of 20.5 mass%.

[0194] The resulting artificial leather had a supple and rich texture, a very smooth feel, a very dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0195] [Example 2] An artificial leather was obtained in the same manner as in Example 1, except that in the <Step of producing ultrafine fiber> of Example 1, the spinneret for islands-in-sea type composite fiber with 16 islands per hole was changed to a spinneret for islands-in-sea type composite fiber with 8 islands per hole.

[0196] The resulting artificial leather had a supple and substantial feel, a smooth touch, a dense feel, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0197] [Example 3] In the step of forming the nonwoven fabric β in Example 1, 1000 threads / cm 2 When needle punching was performed at a needle punch density of 500 needles / cm 2 An artificial leather was obtained in the same manner as in Example 1, except that the needle punch density was changed to

[0198] The resulting artificial leather had a supple and rich texture, a very smooth feel, a dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0199] [Example 4] In the step of forming an entangled sheet in Example 1, 1500 fibers / cm 2 When needle punching was performed at a needle punch density of 800 needles / cm 2 An artificial leather was obtained in the same manner as in Examples 1 and 2, except that the needle punch density was changed to 1000.

[0200] The resulting artificial leather had a supple and rich texture, a very smooth feel, a very dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0201] [Example 5] In the step of forming an entangled sheet in Example 1, 1500 fibers / cm2 When needle punching was performed at a needle punch density of 2000 needles / cm 2 The needle punch density was changed to 1000 needles / cm in the process of forming nonwoven fabric β. 2 When needle punching was performed at a needle punch density of 1400 needles / cm 2 An artificial leather was obtained in the same manner as in Example 1, except that the needle punch density was changed to

[0202] The resulting artificial leather had a supple and rich texture, a very smooth feel, a very dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0203] [Example 6] In the <Step of forming a precursor sheet> of Example 1, the basis weight was 1008 g / m 2 However, the basis weight was 744g / m 2 An artificial leather was obtained in the same manner as in Example 1, except that the amount of raw cotton was adjusted so as to be:

[0204] The resulting artificial leather had a supple and rich texture, a very smooth feel, a very dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0205] [Example 7] In the step of forming an entangled sheet in Example 1, 1500 fibers / cm 2 When needle punching was performed at a needle punch density of 750 needles / cm 2 The needle punch density was changed to 1000 needles / cm in the process of forming nonwoven fabric β. 2 When needle punching was performed at a needle punch density of 500 needles / cm 2 An artificial leather was obtained in the same manner as in Example 1, except that the needle punch density was changed to

[0206] The resulting artificial leather had a supple and substantial feel, a smooth touch, a dense feel, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0207] [Example 8] In the <Step of forming a precursor sheet> of Example 1, the basis weight was 1008 g / m 2 However, the weight was 1306g / m 2 An artificial leather was obtained in the same manner as in Example 1, except that the amount of raw cotton was adjusted so as to be:

[0208] The resulting artificial leather had a supple and rich texture, a very smooth feel, a very dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0209] [Example 9] In the <Step of forming a precursor sheet> of Example 1, the density of needle punches punched from the entangled sheet side (numbers / cm 2 ):D A and the needle punch density (counts / cm 2 ):D β Ratio of D A / D β An artificial leather was obtained in the same manner as in Example 1, except that the value of the elastic modulus was set to 0.36.

[0210] The resulting artificial leather had a supple and rich texture, a smooth feel, a dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2.

[0211] [Example 10] An artificial leather was obtained in the same manner as in Example 1, except that in the <Step of producing ultrafine fiber-patterning fiber> of Example 1, ultrafine fiber-patterning fiber having an islands-in-sea composite structure consisting of island parts and sea parts was melt-spun under the following conditions. Island component: A mixture of the following components P1 and P2 in a mass ratio of 95:5 P1 Polyethylene terephthalate with an intrinsic viscosity (IV value) of 0.73 P2 A masterbatch in which the above polyethylene terephthalate contains 20% by mass of carbon black (average particle size: 0.02 μm, coefficient of variation (CV) of particle size: 20%) as a black pigment relative to the mass of the masterbatch. Sea component: Polystyrene with an MFR (melt flow rate, measured according to the test method specified in ISO 1133:1997, the same applies below) of 65g / 10min Spinneret: Spinneret for islands-in-sea composite fiber with 16 islands per hole Spinning temperature: 285℃ Island / sea mass ratio: 80 / 20 Discharge rate: 1.2g / min (hole) Spinning speed: 1100m / min.

[0212] The artificial leather obtained had a supple and rich texture, a smooth feel, a dense texture, a uniform surface quality, and excellent abrasion resistance. The results are shown in Tables 1 and 2. Furthermore, the artificial leather obtained in this example had uniform color development and excellent friction fastness compared to the artificial leather obtained in Example 1.

[0213] [Table 1]

[0214] [Table 2]

[0215] [Example 11] An artificial leather was obtained in the same manner as in Example 1.

[0216] <Process for forming a resin part on the surface> Resin was applied to both surfaces of the artificial leather obtained in the above process by rotary coating so that the area ratio of the resin portion to the surface was 60%, and discontinuous polyurethane resin portions (including adhesive layers) were formed on both surfaces. That is, an artificial leather was obtained in which multiple resin portions were scattered like islands on the surface, and the resin portions and raised portions were arranged irregularly and discontinuously. The artificial leather obtained had an elegant surface that was somewhere between the surface texture and feel of nubuck or grain and that of suede, and was superior in strength and abrasion resistance, compared to the artificial leather obtained in Example 1.

[0217] [Table 3]

[0218] [Table 4]

[0219] [Comparative Example 1] In the step of forming an entangled sheet in Example 1, 1500 fibers / cm 2 When needle punching was performed at a needle punch density of 2250 needles / cm 2 The needle punch density was changed to 1000 needles / cm in the process of forming nonwoven fabric β. 2 When needle punching was performed at a needle punch density of 500 needles / cm 2 An artificial leather was obtained in the same manner as in Example 1, except that the needle punch density was changed to

[0220] The artificial leather obtained had a smooth feel and excellent abrasion resistance, but the area ratio of the polymeric elastomer in the cross section of the nonwoven fabric on the entangled sheet side of the artificial leather was outside the specified range, so the artificial leather felt lacking in flexibility, had a poor texture, lacked denseness, and had widely varying surface quality. The results are shown in Tables 5 and 6.

[0221] Comparative Example 2 In the step of forming an entangled sheet in Example 1, 1500 fibers / cm 2 When needle punching was performed at a needle punch density of 750 needles / cm 2 An artificial leather was obtained in the same manner as in Example 1, except that the needle punch density was changed to

[0222] The artificial leather obtained had a smooth feel and excellent abrasion resistance, but felt lacking in flexibility and had an unsatisfactory texture. The results are shown in Tables 5 and 6.

[0223] Comparative Example 3 In the <Step of forming a precursor sheet> of Example 1, the density of needle punches punched from the entangled sheet side (numbers / cm 2 ):D A and the needle punch density (counts / cm 2 ):D β Ratio of D A / D β An artificial leather was obtained in the same manner as in Example 1, except that the value of the tensile strength was set to 0.25.

[0224] The resulting artificial leather had excellent abrasion resistance, but the thickness of the nonwoven fabric on the β side was poor, and it lacked flexibility and fullness, resulting in a poor texture. The average nap length on the β side of the nonwoven fabric was short, resulting in a very rough feel and a very poor denseness, with a surface quality that varied widely. The results are shown in Tables 5 and 6.

[0225] Comparative Example 4 In the <Step of forming a precursor sheet> of Example 1, the density of needle punches punched from the entangled sheet side (numbers / cm 2 ):D A and the needle punch density (counts / cm 2 ):D β Ratio of D A / D β An artificial leather was obtained in the same manner as in Example 1, except that the value of the tensile strength was set to 0.88.

[0226] The artificial leather obtained had a supple and rich feel and was excellent in abrasion resistance, but because the average nap length on the entangled sheet side was short, it had a rough feel to the touch, lacked denseness, and had widely varying surface quality. The results are shown in Tables 5 and 6.

[0227] [Table 5]

[0228] [Table 6]

[0229] As shown in Tables 1 to 4, the artificial leathers of Examples 1 to 11 comprised a fiber-entangled body including a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter within a predetermined range, a woven or knitted fabric, and a polymeric elastomer, and both surfaces had napped structures. The ratio of the apparent densities of the entangled sheet and the nonwoven fabric β was set within a predetermined range before the precursor sheet formation step. Furthermore, the ratio of the needle-punching density from the entangled sheet side to the needle-punching density from the nonwoven fabric β side was set within a predetermined range during the precursor sheet formation step, thereby achieving a predetermined thickness for the nonwoven fabric. Furthermore, in the cross section of the artificial leather, the area excluding the napped portion of the nonwoven fabric was divided into three equal parts in the thickness direction, and the ratio of the area percentage of the polymeric elastomer in the nap-most part to the area percentage of the polymeric elastomer in the woven or knitted fabric side was within a predetermined range. Due to these features, the artificial leathers of Examples 1 to 11 had an elegant appearance on both surfaces, and also had a solid feel, flexibility, high strength, and abrasion resistance.

[0230] On the other hand, as shown in Tables 5 and 6, in the artificial leather of Comparative Example 1, the ratio of the apparent densities of the entangled sheet and the nonwoven fabric β was outside the specified range, so that in the cross section of the artificial leather, the region excluding the napped portion from the nonwoven fabric portion was divided into three equal parts in the thickness direction, and the ratio of the area percentage of the polymer elastomer in the nap-most portion to the area percentage of the polymer elastomer in the woven / knitted fabric portion was outside the specified range, and the thickness ratio of one nonwoven fabric to the other nonwoven fabric was also outside the specified range. Therefore, the artificial leather did not have a supple texture despite its thickness, and an elegant surface appearance could not be achieved on both surfaces.

[0231] In addition, in the artificial leather of Comparative Example 2, the ratio of the apparent density of the entangled sheet to the nonwoven fabric β was outside the specified range, and therefore, in the cross section of the artificial leather, the area excluding the napped portion from the nonwoven fabric portion was divided into three equal parts in the thickness direction, and the ratio of the area percentage of the polymer elastomer in the nap-most part to the area percentage of the polymer elastomer in the woven / knitted fabric side part was outside the specified range. Therefore, it was not possible to obtain an artificial leather that was thick but had a supple texture.

[0232] Furthermore, in the artificial leathers of Comparative Examples 3 and 4, in the precursor sheet formation process, the ratio of the needle punch density from the entangled sheet side to the needle punch density from the nonwoven fabric β side was outside the specified range, which resulted in the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric being outside the specified range, and as a result, despite the high thickness, the artificial leathers were unable to have a supple texture, and were unable to achieve a good feel or an elegant surface appearance on both surfaces. [Industrial Applicability]

[0233] The artificial leather of the present invention can be used in a wide range of applications, such as automobile interior materials, furniture, miscellaneous goods, clothing, etc. Among these, the artificial leather of the present invention has an elegant surface appearance on both surfaces, is excellent in solidity and suppleness, and further has excellent strength and abrasion resistance, making it particularly suitable for application to miscellaneous goods, etc. [Explanation of symbols]

[0234] 1:Artificial leather 2: Pierrection part 3: Base material part 4: Woven and knitted fabrics 5: Resin part

Claims

1. a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less; Woven and knitted fabrics, A fiber-entangled body comprising: A polymeric elastomer; An artificial leather having both surfaces with raised nap, The fiber-entangled body is formed by laminating the nonwoven fabric, the woven or knitted fabric, and the nonwoven fabric in this order, the nonwoven fabrics each have a thickness of 1.0 mm or more and 2.0 mm or less, and the ratio of the thickness of one nonwoven fabric to the other nonwoven fabric is within a range of 3 / 5 to 5 / 3; An artificial leather that satisfies the following formula 1 in a cross section of the artificial leather. 0.5≦R １ / R ２ ≦0.9 ・・・(Formula 1) where: R １ : Area ratio (%) of the polymer elastomer in the most napped part of the cross section of the artificial leather, in the region excluding the napped part from the nonwoven fabric part, divided into three equal parts in the thickness direction R ２ : Area ratio (%) of the polymer elastomer in the part closest to the woven or knitted fabric in the cross section of the artificial leather, which is obtained by dividing the area of ​​the nonwoven fabric excluding the napped part into three equal parts in the thickness direction

2. 2. The artificial leather according to claim 1, wherein the area ratio of the polymeric elastomer to the entire cross section of the artificial leather is 5.0% or more and 15.0% or less.

3. 3. The artificial leather according to claim 1, wherein the area ratio of the polymeric elastomer measured from the surface of the artificial leather is 0.01% or more and 3.00% or less on both surfaces.

4. 3. The artificial leather according to claim 1, wherein the average nap length of at least one surface of the artificial leather is 200 μm or more and 600 μm or less.

5. 3. The artificial leather according to claim 1, wherein a discontinuous resin portion is formed on at least one surface of the artificial leather.

6. a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.01 μm or more and 10.00 μm or less; Woven and knitted fabrics, A fiber-entangled body comprising: A polymeric elastomer; A method for producing artificial leather having raised nap on both surfaces, a step of entangling a woven or knitted fabric on one side of nonwoven fabric α made of ultrafine fiber-developing fibers to form an entangled sheet; A step of forming a nonwoven fabric β made of ultrafine fiber development type fibers; a step of laminating the entangled sheet and the nonwoven fabric β so that the woven or knitted fabric is sandwiched between the nonwoven fabric α and the nonwoven fabric β, and entangled and integrated by needle punching to form a precursor sheet; applying a water-soluble resin to the precursor sheet to form a water-soluble resin-coated sheet; generating ultrafine fibers from the ultrafine fiber-developing fibers in the water-soluble resin-coated sheet to form an ultrafine fiber sheet; a step of providing a polymeric elastomer to the ultrafine fiber sheet to form a polymeric elastomer-coated sheet; grinding both surfaces of the polymeric elastomer-attached sheet to form a raised sheet; and In the step of forming the precursor sheet, The entangled sheet and the nonwoven fabric β before being entangled and integrated satisfy the following formula 2: The entanglement and integration satisfies the following formula 3: A method for manufacturing artificial leather. 0.30≦V β１ / V Ａ ≦0.80 ・・・(Formula 2) 0.30≦D Ａ / D β ≦0.70 ・・・(Formula 3) where: V Ａ : Apparent density (g / cm) of the entangled sheet before entanglement and integration ３ ) V β１ : Apparent density (g / cm ) of the nonwoven fabric β before the entanglement and integration ３ ) D Ａ : Needle punch density (numbers / cm) punched from the entangled sheet side ２ ) D β : Needle punch density (number / cm) punched from the β side of the nonwoven fabric ２ )

7. The V Ａ and the V β１ However, both are 0.01 g / cm ３ 0.30g / cm or more ３ The method for producing an artificial leather according to claim 6, wherein:

8. The method for producing an artificial leather according to claim 6 or 7, wherein in the step of forming the water-soluble resin-applied sheet, the water-soluble resin is applied in an amount of 0.1% by mass to 30.0% by mass relative to the mass of the precursor sheet.

9. 8. The method for producing an artificial leather according to claim 6, wherein in the step of forming the polymeric elastomer-attached sheet, the polymeric elastomer is applied in an amount of 10% by mass to 40% by mass relative to the mass of the water-soluble resin-attached sheet.

10. 8. The method for producing an artificial leather according to claim 6, further comprising the step of applying a resin to a surface of the raised sheet to form a discontinuous resin portion on at least one surface of the artificial leather.

11. Miscellaneous goods comprising the artificial leather according to claim 1 or 2.

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