Artificial leather and method for manufacturing same

Abstract

The present invention addresses the problem of providing artificial leather having an elegant and luxurious appearance, high strength, and exceptional flexibility. This artificial leather (11a, 11b) comprises a long-fiber nonwoven fabric configured from thermoplastic resin fibers that are crimped fibers. One surface of the artificial leather (11a, 11b) has a napped part (12) having napped fibers and / or a resin layer (14). The artificial leather (11a, 11b) satisfies the following expressions 1 to 4 for a portion PＳ１ (191), a portion PＣ (192), and a portion PＳ２ (193) in a cross-section parallel to the thickness direction of the artificial leather (11a, 11b).　(Exp. 1) 1.4 × φPS1 ≤ φPC ≤ 4.0 × φPS1. (Exp. 2) 0.05 ≤ rPS1 ≤ 0.20. (Exp. 3) 0.05 ≤ rPS2 ≤ 0.20. (Exp. 4) 0.05 ≤ rPC ≤ 0.20. The symbols φPS1 and φPC denote the average circular equivalent diameters (μm) of the thermoplastic resin fibers in the portions PS1(191) and PC(192), and rPS1, rPC, and rPS2 denote the curvatures of the thermoplastic resin fibers in the portions PS1(191), PC(192), and PS2(193).

Description

Artificial leather and method for manufacturing the same

[0001] This invention relates to artificial leather.

[0002] Artificial leather, with its elegant appearance and feel, as well as its good heat resistance and colorfastness, is used in a wide range of applications, from shoes, bags, clothing, furniture, and sporting goods to general industrial uses such as automotive interiors and seats, and even industrial products.

[0003] Such artificial leather has achieved a high level of appearance and physical properties by forming a uniform sheet using a method of laminating a web made of ultrafine fiber-generating staples in a cross-layer structure.

[0004] However, in recent years, there has been an increasing demand for even higher levels of appearance and physical properties, as well as a growing emphasis on environmental considerations, which has led to a need for process simplification.

[0005] Furthermore, electric vehicles often feature simple yet highly designed interiors, and there is a growing trend to avoid using natural leather from an environmental perspective. As a result, artificial leather is increasingly being used in areas with complex shapes, such as ceiling materials, door trims, and instrument panels. Therefore, there is a demand for highly flexible artificial leather that can be easily molded to fit complex shapes.

[0006] For example, Patent Document 1 proposes a full-grain artificial leather comprising a base layer composed of ultrafine fibers with an average single fiber diameter of 0.1 to 10 μm and a porous elastic polymer, and a resin layer formed on at least one side of the base layer, wherein the base layer has a structure in which fiber bundles made of the ultrafine fibers are intertwined with each other, and the ultrafine fibers have crimp in a cross section perpendicular to the thickness direction on the side of the base layer that is in contact with the resin layer.

[0007] Patent Document 2 proposes a napped artificial leather base material comprising a nonwoven fabric which is an entanglement of fibers (A) and fibers (B), and a polymeric elastic body applied to the interior of the nonwoven fabric, wherein the fibers (A) are crimped fibers formed from two types of resins with different intrinsic viscosities and are long fibers having an average fineness above a certain level, and the fibers (B) are ultrafine fibers having an average fineness below a certain level, and one side of the base material is napped.

[0008] Furthermore, Patent Document 3 proposes an artificial leather composed of a fiber entanglement body containing ultrafine fibers with a single fiber fineness of a certain degree or less and a polymer elastic body, and having a napped surface, wherein the ultrafine fibers are latent crimp-exhibiting polyester composite fibers in which two types of polytrimethylene terephthalate having a specific range of intrinsic viscosity differences are compounded side-by-side with each other.

[0009] Japanese Patent Publication No. 2018-3181, International Publication No. 2020 / 044911, Japanese Patent Publication No. 2003-286663

[0010] The technology disclosed in Patent Document 1 is characterized in that it includes the steps of: applying a micronization treatment to a sheet-like material made of micron-fiber-generating fibers to generate micron fibers and obtain a sheet-like material B; and applying a heat treatment to generate crimp in the micron fibers of the base layer. In this case, since the crimped fibers are obtained using micron-fiber-generating fibers, it is necessary to melt and extrude at least three polymer components separately, which complicates the spinning equipment and necessitates a process to remove marine components in order to generate micron fibers, leaving room for improvement in terms of productivity. Furthermore, because micron-fiber-generating fibers are used, micron fibers generated from the same micron-fiber-generating fiber tend to gather together to form fiber bundles, leaving room for improvement in obtaining a sheet with a uniform appearance in which each fiber is dispersed.

[0011] Furthermore, the technology disclosed in Patent Document 2, like that in Patent Document 1, requires a process to remove marine components in order to produce ultrafine fibers, so there is room for improvement in terms of productivity. Moreover, since the artificial leather contains an entanglement of crimped fibers (A) and non-crimped fibers (B), when the artificial leather is bent, the non-crimped fibers are stretched out, resulting in insufficient flexibility.

[0012] Furthermore, the technology disclosed in Patent Document 3 describes obtaining artificial leather by a process that directly obtains ultrafine fibers and then forms them into a nonwoven fabric. In this case, although the process of generating ultrafine fibers is unnecessary, on the other hand, in order to uniformly disperse the fibers in water, the fiber length must be shortened, making it difficult to obtain artificial leather with an elegant and luxurious appearance and high physical properties. In addition, in order to prevent polytrimethylene terephthalate composite fibers, which are compounded side by side and exhibit latent crimp, from entangling in water, the rigidity of the fibers must be high, making it difficult to obtain flexible artificial leather.

[0013] Therefore, the objectives of the present invention are to provide artificial leather with an elegant and luxurious appearance, high strength, and excellent flexibility, and to provide a method for manufacturing artificial leather that can further reduce environmental impact while also improving productivity.

[0014] The inventors, through diligent research to solve the above problems, discovered that when observing the cross-section of artificial leather obtained by a specific method using specific fibers as constituent fibers, it exhibits unique fiber morphologies depending on the observation position. They then found that artificial leather with this composition can solve the above problems, that is, it can provide artificial leather with an elegant and luxurious appearance, high strength, and excellent flexibility.

[0015] This invention was completed based on these findings, and according to this invention, the following inventions are provided.

[0016] [1] An artificial leather comprising a long fiber non-woven fabric composed of thermoplastic resin fibers that are crimped fibers, wherein one surface of the artificial leather has a pile portion having pile and / or a resin layer, in a cross-section parallel to the thickness direction of the artificial leather, a virtual line A is drawn at a distance of 10% of the thickness of the artificial leather from the reference line of the surface having the pile portion and / or the resin layer toward the reference line of the other surface, a virtual line B is drawn at a distance of 25% of the thickness of the artificial leather from the reference line of the surface having the pile portion and / or the resin layer toward the reference line of the other surface, a virtual line C is drawn at a distance of 35% of the thickness of the artificial leather from the reference line of the surface having the pile portion and / or the resin layer toward the reference line of the other surface, a virtual line D is drawn at a distance of 90% of the thickness of the artificial leather from the reference line of the surface having the pile portion and / or the resin layer toward the reference line of the other surface, respectively, and a portion from the reference line of the one surface to the virtual line A is portion P Ｓ１ , a portion from the virtual line B to the virtual line C is portion P Ｃ , a portion from the virtual line D to the other surface is portion P Ｓ２ , and when defined as such, an artificial leather that satisfies the following formulas (1) to (4).

[0017] 1.4×φ ＰＳ１ ≤φ ＰＣ ≤4.0×φ ＰＳ１ ... (Formula 1) 0.05 ≤ r ＰＳ１ ≤0.20... (Formula 2) 0.05 ≤ r ＰＳ２ ≤0.20... (Formula 3) 0.05 ≤ r ＰＣ ≤0.20... (Formula 4) Here, φ ＰＳ１ is the average circle equivalent diameter (μm) of the thermoplastic resin fibers in the portion P Ｓ１ , φ ＰＣ is the average circle equivalent diameter (μm) of the thermoplastic resin fibers in the portion P Ｃ , r ＰＳ１ is the curvature of the thermoplastic resin fibers in the portion P Ｓ１ , r ＰＣ is the curvature of the thermoplastic resin fibers in the portion P Ｃ is the curvature of the thermoplastic resin fibers in the portion PＰＳ２ is the aforementioned part P Ｓ２ This is the curvature of the thermoplastic resin fiber in the given context.

[0018] [2] The above φ ＰＳ１ The artificial leather described in [1] above, wherein the thickness is 2.0 μm or more and 10.0 μm or less.

[0019] [3] Said part P Ｃ The artificial leather according to [1] or [2], wherein the thermoplastic resin fiber has a region α in which the elastic modulus at 25°C measured by an atomic force microscope is 20 MPa or more and 400 MPa or less, and a region β in which the elastic modulus at 25°C measured by an atomic force microscope is 1000 MPa or more and 5000 MPa or less, and the region α and the region β have a portion in which they are connected three or more times in the order of region α, region β, region α, region β, region α.

[0020] [4] Furthermore, the artificial leather described in any of [1] to [3] above, which satisfies the following formula 5.

[0021] 1.4 × φ ＰＳ２ ≦φ ＰＣ ≤4.0 × φ ＰＳ２ ... (Equation 5) Here, φ ＰＳ２ is the aforementioned part P Ｓ２ This is the average circular equivalent diameter of the thermoplastic resin fibers in the given location.

[0022] [5] Furthermore, artificial leather according to any of [1] to [4] above that satisfies the following formula 6: 0.8 × φ ＰＳ２ ≦φ ＰＣ ≤ 1.2 × φ ＰＳ２ ... (Equation 6) Here, φ ＰＳ２ is the aforementioned part P Ｓ２ This is the average circular equivalent diameter of the thermoplastic resin fibers in the given location.

[0023] [6] The artificial leather according to any one of [1] to [5], wherein the thermoplastic resin fiber contains a pigment, and the area ratio of the pigment in the thermoplastic resin fiber to the cross-section of the thermoplastic resin fiber is in the range of 0.01% to 13%.

[0024] [7] The artificial leather according to any one of [1] to [6], wherein the artificial leather contains polyurethane resin.

[0025] [8] The artificial leather according to [7], wherein the polyurethane resin contains a pigment, and the content of the pigment in the polyurethane resin is in the range of 0.1% by mass or more and 10.0% by mass or less.

[0026] [9] A method for manufacturing artificial leather according to any one of [1] to [8], comprising: discharging a thermoplastic resin from the discharge hole of a die, blowing gas to include at least a portion of the area within 200 mm from the discharge hole to form a yarn, and pulling at a spinning speed of 3000 m / min or more and 7000 m / min or less to form thermoplastic resin fibers; collecting the thermoplastic resin fibers to form a fiber web; heat treating the fiber web at 70°C or more and 250°C or less to form crimped fibers from the thermoplastic resin fibers to form a crimped fiber web; and polishing or entangling at least one surface of the crimped fiber web with water.

[0027]

[10] The method for producing artificial leather according to [9], wherein in the step of forming the thermoplastic resin fibers, a pigment is added to the thermoplastic resin A and / or the thermoplastic resin B, and the area ratio of the pigment in the thermoplastic resin fibers to the cross-section of the thermoplastic resin fibers is in the range of 0.01% or more and 13.00% or less.

[0028]

[11] A vehicle interior material comprising artificial leather as described in any of [1] to [8] above.

[0029]

[12] A vehicle component comprising artificial leather as described in any of [1] to [8] above.

[0030]

[13] A seat comprising artificial leather as described in any of [1] to [8] above.

[0031]

[14] A vehicle comprising at least one of the vehicle interior material described in

[11] , the vehicle component described in

[12] , and the seat described in

[13] .

[0032]

[15] Clothing containing artificial leather as described in any of [1] to [8] above.

[0033] According to the present invention, it is possible to obtain artificial leather that is highly productive, has an elegant and luxurious appearance, high strength, and excellent flexibility. Due to the excellent properties of this artificial leather, it can be suitably used in vehicle interior materials, vehicle parts, and even seats.

[0034] Figure 1 shows the imaginary lines A to D in a cross-section parallel to the thickness direction of the artificial leather according to this embodiment, and part P. Ｓ１ , P Ｃ , P Ｓ２ Figure 1 is a cross-sectional conceptual diagram for explaining the following: Figure 2 is a diagram illustrating and explaining a planar, wavy form of thermoplastic resin fiber (crimped fiber) according to this embodiment. Figure 3 is a diagram illustrating and explaining a coiled form of thermoplastic resin fiber (crimped fiber) according to this embodiment. Figure 4 is a cross-sectional conceptual diagram illustrating and explaining one embodiment of thermoplastic resin fiber (crimped fiber) according to this embodiment. Figure 5 is a cross-sectional conceptual diagram for explaining the method of measuring and calculating the pile length of artificial leather according to this embodiment. Figure 6 is a cross-sectional conceptual diagram illustrating and explaining a form of artificial leather according to this embodiment that has a resin layer, where substantially the entire surface is covered with the resin layer (grain-like artificial leather). Figure 7 is a cross-sectional conceptual diagram illustrating and explaining a form of artificial leather according to this embodiment that has a resin layer, where a part of the surface is covered with the resin layer (semi-grain-like artificial leather). Figure 8 is a cross-sectional conceptual diagram for explaining the method of measuring and calculating the curvature of thermoplastic resin fiber (crimped fiber) according to this embodiment. Figure 9 is a conceptual cross-sectional diagram illustrating one embodiment of the thermoplastic resin fiber (crimped fiber) according to this embodiment, and in particular for explaining the number of connected thermoplastic resin fibers. Figure 10 is a conceptual diagram showing the vicinity of the discharge holes of the die as observed from the downstream side, illustrating and explaining one embodiment of the arrangement of the discharge holes of the die used in the method for manufacturing artificial leather according to this embodiment.

[0035] The present invention relates to artificial leather comprising a long-fiber nonwoven fabric composed of thermoplastic resin fibers which are crimped fibers, wherein one surface of the artificial leather has a pile portion having a pile and / or a resin layer, and in a cross section parallel to the thickness direction of the artificial leather, a virtual line A is drawn from the reference line of the surface having the pile portion and / or the resin layer to the reference line of the other surface at a distance of 10% of the thickness of the artificial leather, a virtual line B is drawn from the reference line of the surface having the pile portion and / or the resin layer to the reference line of the other surface at a distance of 25% of the thickness of the artificial leather, a virtual line C is drawn from the reference line of the surface having the pile portion and / or the resin layer to the reference line of the other surface at a distance of 35% of the thickness of the artificial leather, and a virtual line D is drawn from the reference line of the surface having the pile portion and / or the resin layer to the reference line of the other surface at a distance of 90% of the thickness of the artificial leather, and the portion from the reference line of the one surface to the reference line A is defined as part P Ｓ１ The portion from the virtual line B to the virtual line C is part P Ｃ The portion from the virtual line D to the reference line of the other surface is part P. Ｓ２ When , the following equations 1 to 4 are satisfied.

[0036] 1.4 × φ ＰＳ１ ≦φ ＰＣ ≤4.0 × φ ＰＳ１ ...(Formula 1) 0.05≦r ＰＳ１ ≦0.20 ... (Formula 2) 0.05≦r ＰＳ２ ≦0.20 ... (Formula 3) 0.05≦r ＰＣ ≤ 0.20 ... (Equation 4) where φ ＰＳ１ is the aforementioned part P Ｓ１ The average equivalent diameter (μm) of the thermoplastic resin fibers in φ ＰＣ is the aforementioned part P Ｃ The average equivalent circle diameter (μm) of the thermoplastic resin fibers in r ＰＳ１ is the aforementioned part P Ｓ１ The curvature of the thermoplastic resin fiber in the above, r ＰＣ is the aforementioned part P Ｃ The curvature of the thermoplastic resin fiber in the above, rＰＳ２ is the aforementioned part P Ｓ２ This is the curvature of the thermoplastic resin fiber in the given context.

[0037] The components will be described in detail below, but the present invention is not limited in any way to the scope described below, as long as it does not exceed the spirit of the invention, and various modifications are possible without departing from the spirit of the invention.

[0038] Note that virtual lines A to D and section P Ｓ１ , part P Ｃ , part P Ｓ２ The details are outlined in Figure 1. The left side of Figure 1 is a conceptual cross-sectional view of artificial leather with a piled surface on one side, and the right side is a conceptual cross-sectional view of artificial leather with a resin layer on one side. Furthermore, when drawing these dotted lines, "thickness of artificial leather" refers to the distance from the reference line on one surface (the piled surface and / or the surface with the resin layer) to the reference line on the other surface, measured and calculated by the following method, and is different from the "thickness of artificial leather" described later. <Measurement and calculation method of "thickness of artificial leather" when drawing dotted lines> (i) Cut out a 2cm x 2cm test piece. (ii) Photograph the cross-section of the test piece at a magnification of 200x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). Note that the width direction of the cross-section of the test piece should be parallel to the long side of the SEM image. (iii) In the captured SEM image, as illustrated in the cross-sectional conceptual diagram of the artificial leather shown in Figure 1, a virtual line 181 is drawn parallel to the long side of the SEM image and passing through the tip 15 of the pile portion 12 or the end 16 of the resin portion 14, and this is used as the reference line for one surface. Similarly, a virtual line 182 is drawn passing through the end 17 of the other surface of the artificial leather 11a or 11b, and this is used as the reference line for the other surface. The virtual lines 181 and 182 are to be straight lines parallel to each other, and the distance between the virtual lines 181 and 182 is to be maximized. This distance is defined as the "thickness of the artificial leather" when drawing the virtual lines. Then, based on the above measurement and calculation method, virtual lines A to D are drawn using the following method, and section P Ｓ１ , part P Ｃ , part P Ｓ２Identify the following: (i) From the reference line (virtual line 181) on one surface to the reference line (virtual line 182) on the other surface, draw virtual lines A to D as follows: - Distance of 10% of the "thickness of the artificial leather": virtual line A (18A in Figure 1) - Distance of 25% of the "thickness of the artificial leather": virtual line B (18B in Figure 1) - Distance of 35% of the "thickness of the artificial leather": virtual line C (18C in Figure 1) - Distance of 90% of the "thickness of the artificial leather": virtual line D (18D in Figure 1) (ii) Part P Ｓ１ , part P Ｃ , part P Ｓ２ The following is how it is identified: • The portion from the reference line (virtual line 181) on one surface to virtual line A (18A in Figure 1): Part P Ｓ１ (191 in Figure 1) - The portion from virtual line B (18B in Figure 1) to virtual line C (18C in Figure 1): Part P Ｃ (192 in Figure 1) - The portion from the imaginary line D (18D in Figure 1) to the reference line of the other surface (imaginary line 182): Part P Ｓ２ (Figure 1, 193).

[0039] [Thermoplastic Resin Fibers] The artificial leather of one embodiment of the present invention (hereinafter also referred to as "this embodiment") includes a long-fiber nonwoven fabric composed of thermoplastic resin fibers which are crimped fibers. Here, these thermoplastic resin fibers are fibers whose main component is thermoplastic resin, and crimped fibers are either planar, wavy fibers as illustrated in Figure 2, or fibers that have at least a portion of a substantially coil-shaped (spiral, or helical spring-shaped) part (hereinafter sometimes referred to as a coil portion) that forms one or more coil crimps, as illustrated in Figure 3. Furthermore, in "fibers whose main component is thermoplastic resin," "thermoplastic resin as the main component" means thermoplastic resin with a content in the fiber of more than 50% by mass.

[0040] From the viewpoint of abrasion resistance, particularly mechanical strength, and heat resistance, polyester resins are preferably exemplified as the thermoplastic resin.

[0041] Furthermore, depending on the purpose, the thermoplastic resin may contain inorganic particles such as titanium dioxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, antibacterial agents, etc., to the extent that it does not hinder the purpose of the present invention.

[0042] Furthermore, the thermoplastic resin fiber is preferably a composite fiber, and more preferably a side-by-side composite fiber, an eccentric core-sheath composite fiber, or an asymmetrical cooling fiber.

[0043] In particular, with respect to the thermoplastic resin fiber, <1> the portion P Ｃ Preferably, the thermoplastic resin fiber in the material has a region α in which the elastic modulus at 25°C measured by an atomic force microscope is 20 MPa or more and 400 MPa or less, and a region β in which the elastic modulus at 25°C measured by an atomic force microscope is 1000 MPa or more and 5000 MPa or less, and preferably, the region α and the region β are connected three or more times in the order of region α, region β, region α, region β, region α. ​​When the thermoplastic resin fiber is in the above configuration, it becomes an artificial leather that achieves both a flexible texture and mechanical strength.

[0044] First, regarding <1>, the aforementioned part P Ｃ In this invention, the thermoplastic resin fibers preferably have a region α in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 20 MPa and 400 MPa. Since this region α can play a role similar to that of a polymeric elastic material such as polyurethane in artificial leather as described in Patent Document 1, including composite fibers having region α results in artificial leather that is flexible, has a moderate firmness, and has good stretch.

[0045] This region α preferably contains a thermoplastic elastomer resin (hereinafter sometimes abbreviated as "TPE") as its main component. Here, in the present invention, "contained as a main component" means that the component is contained in an amount of 50% by mass or more of the total constituent components. For example, when it is stated in the present invention that "A contains B as a main component," it means that B is contained in A in an amount of at least 50% by mass. The same applies hereafter. Examples of the thermoplastic elastomer resin include melt-spun polyurethane elastomers, polyester elastomers obtained by copolymerizing polybutylene terephthalate with various aliphatic polyols, polyamide elastomers obtained by copolymerizing various polyamides with various aliphatic polyols, polystyrene-based polystyrene elastomers, and olefin elastomers. Among these, it is preferable that the thermoplastic elastomer is a block copolymer copolymer in which the hard segment is polybutylene terephthalate and the soft segment is polyether. By including this block copolymer as the main component in region α of the thermoplastic resin fiber, an artificial leather with excellent texture, tensile strength, and tensile elongation is produced.

[0046] Furthermore, depending on the purpose, the thermoplastic elastomer resin may contain inorganic particles such as titanium dioxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, antibacterial agents, etc., to the extent that it does not hinder the purpose of the present invention.

[0047] In this region α, the elastic modulus at 25°C, as measured by an atomic force microscope (hereinafter sometimes abbreviated as "elastic modulus of region α"), is 20 MPa or more and 400 MPa or less. Furthermore, when the average elastic modulus of this region α at 25°C, as measured by an atomic force microscope (hereinafter sometimes abbreviated as "average elastic modulus of region α") is preferably 30 MPa or more, more preferably 40 MPa or more, it becomes a flexible composite fiber, and consequently, an artificial leather with a flexible texture and stretchability. On the other hand, when the elastic modulus of the aforementioned region α is preferably 350 MPa or less, more preferably 300 MPa or less, and even more preferably 250 MPa or less, it becomes a flexible and elastic thermoplastic resin fiber, and consequently, an artificial leather with a moderately firm texture.

[0048] The elastic modulus and mean elastic modulus of region α are measured and calculated by the following method: (i) One test piece measuring 5 mm in width and 10 mm in length is randomly cut from the artificial leather. (ii) The cross-section of this test piece is cut under frozen conditions using a cryomicrotome (e.g., Leica's "Ultracut-UCT") to produce a precise cross-section of the test piece. (iii) The probe of the atomic force microscope (e.g., Bruker Japan's "NanoScope V Dimension Icon" probe microscope) is calibrated (e.g., Bruker Japan's "RTESPA-150" RTESPA type silicon probe). Calibration can be performed by measuring the bend sensitivity of the probe cantilever on a sapphire plate and measuring the spring constant of the probe cantilever using the thermal vibration method. (iv) An AFM image is taken of the central portion of the precision cross section of the test specimen, when the thickness direction of the artificial leather, excluding the pile, is divided into three parts, using an atomic force microscope. (v) From the AFM image obtained in (iv), a region is identified in which the cross section of at least one fiber is completely contained, and the elastic modulus is measured in a 20 μm square area on the precision cross section of the test specimen using the force volume method of the atomic force microscope (a force curve is obtained by pressing the cantilever of the atomic force microscope probe perpendicular to the precision cross section of the test specimen and then releasing it). An elastic modulus image is obtained. (vi) For the obtained elastic modulus image, the display scale for the elastic modulus is set from 20 MPa to 400 MPa, and the region in which the cross section of one fiber falls within the color range of the scale bar is defined as region α. ​​However, in order to exclude the influence of measurement outliers and noise, a) even if the region is between 20 MPa and 400 MPa, regions smaller than 200 nm square are not designated as region α. b) Even if there is a region with a pressure of less than 20 MPa or more than 400 MPa within the region of 20 MPa to 400 MPa, if that region is less than 200 nm square, that region shall be considered region α. ​​(vii) In a field of view that includes only one fiber as defined in (vi) and in which region α within the fiber occupies at least 70% of the measurement area, the elastic modulus is measured by the force volume method in the same manner as in (v) to obtain an elastic modulus image.For the elastic modulus image obtained in (viiii), the display scale of the elastic modulus is set from 20 MPa to 400 MPa, and the peak value of the histogram of the obtained elastic modulus is taken as the average value (MPa) of region α. ​​Repeat (ix) (vii) to (viiii) for three fields of view, and the arithmetic mean (MPa) of the average value (the value obtained in (viiii)) within region α of the three fields of view is rounded to the first decimal place and taken as the average elastic modulus of region α.

[0049] Furthermore, the average modulus of region α can be changed depending on the modulus of the thermoplastic elastomer resin used, and can be adjusted by the type of polymer, average molecular weight, ratio of soft segments to hard segments, crosslinking density, etc.

[0050] Next, with respect to <2>, the aforementioned part P Ｃ In this invention, it is preferable that the thermoplastic resin fibers have a region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1,000 MPa and 5,000 MPa. This region β plays a role in the development of high mechanical properties in the thermoplastic resin fibers, and by including thermoplastic resin fibers having region β, an artificial leather with high tensile strength and excellent abrasion resistance is obtained.

[0051] Region β preferably contains a polyester resin as its main component. Examples of this polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polylactic acid, and polyester elastomer. Among these, it is more preferable that the polyester resin is polyethylene terephthalate or polybutylene terephthalate, and even more preferable that it is polyethylene terephthalate. By having region β of the composite fiber contain this polyester resin as its main component, an artificial leather with superior texture and practical performance is obtained.

[0052] In this embodiment, the term "polyester resin" refers to each of the polyester resins described above, such as polyethylene terephthalate, mixtures thereof, copolymers, and resins to which additives have been added. These additives are added and included in a range that does not hinder the objectives of the present invention, depending on the purpose, and specifically include inorganic particles such as titanium dioxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents.

[0053] In this region β, the elastic modulus at 25°C, as measured by an atomic force microscope (hereinafter sometimes abbreviated as "elastic modulus of region β") is between 1000 MPa and 5000 MPa. Furthermore, if the average elastic modulus of this region β at 25°C, as measured by an atomic force microscope (hereinafter sometimes abbreviated as "average elastic modulus of region β") is preferably 1200 MPa or higher, more preferably 1400 MPa or higher, and even more preferably 1600 MPa or higher, it results in a thermoplastic resin fiber with high tensile strength, and consequently, an artificial leather that is thin yet strong and less prone to thread breakage due to friction. On the other hand, if the elastic modulus of region β is preferably 4800 MPa or lower, more preferably 4600 MPa or lower, and even more preferably 4500 MPa or lower, it results in a thermoplastic resin fiber with low rigidity, and consequently, an artificial leather with a soft, fuzzy texture.

[0054] The elastic modulus and mean elastic modulus of region β are measured and calculated by the following method: (i) One test piece measuring 5 mm in width and 10 mm in length is randomly cut from the artificial leather. (ii) The cross-section of this test piece is cut under frozen conditions using a cryomicrotome (e.g., Leica's "Ultracut-UCT") to prepare a precise cross-section of the test piece. (iii) The probe of the atomic force microscope (e.g., Bruker Japan's "NanoScope V Dimension Icon" probe microscope) is calibrated (e.g., Bruker Japan's "RTESPA-150" RTESPA type silicon probe). Calibration can be performed by measuring the warp sensitivity of the probe cantilever on a sapphire plate and measuring the spring constant of the probe cantilever using the thermal vibration method. (iv) An AFM image is taken of the central portion of the precision cross section of the test specimen, when the thickness direction of the artificial leather, excluding the pile, is divided into three parts, using an atomic force microscope. (v) From the AFM image obtained in (iv), a region is identified in which the cross section of at least one fiber is completely contained, and the elastic modulus is measured in a 20 μm square area on the precision cross section of the test specimen using the force volume method of the atomic force microscope (a method in which the cantilever of the atomic force microscope probe is pressed against the precision cross section of the test specimen perpendicular to it and then released to obtain a force curve), and an elastic modulus image is obtained. (vi) For the obtained elastic modulus image, the display scale for the elastic modulus is set from 1000 MPa to 5000 MPa, and the region in which the cross section of one fiber falls within the color range of the scale bar is defined as region β. However, in order to exclude the influence of measurement outliers and noise, a) even if the region is between 1000 MPa and 5000 MPa, regions smaller than 200 nm square are not designated as region β. b) Even if there is a region with less than 1000 MPa or more than 5000 MPa within the region with 1000 MPa or more and 5000 MPa or less, if that region is less than 200 nm square, that region shall be considered region β. (vii) In a field of view that includes only one fiber as defined in (vi) and in which region β within the fiber occupies at least 70% of the measurement area, the elastic modulus is measured by the force volume method in the same manner as in (v) to obtain an elastic modulus image.For the elastic modulus image obtained in (viiii), the display scale of the elastic modulus is set from 1000 MPa to 5000 MPa, and the peak value of the histogram of the obtained elastic modulus is taken as the mean value (MPa) of region β. Repeat (ix) (vii) to (viiii) for three fields of view, and the arithmetic mean (MPa) of the mean values ​​(values ​​obtained in (viiii)) within region α of the three fields of view is rounded to the first decimal place and taken as the mean elastic modulus of region β.

[0055] Furthermore, the average modulus of region β can be adjusted by factors such as the type of polymer, average molecular weight, and spinning rate.

[0056] And, regarding <3>, the aforementioned part P Ｃ In the composite fiber, it is preferable that the region α and the region β are joined three or more times in the order of region α, region β, region α, region β, region α. ​​A composite fiber having this joined portion (hereinafter sometimes abbreviated as "joint portion") is, for example, a composite fiber having a cross-section as illustrated in Figure 4. In this figure, in the cross-section of any composite fiber, region α41 and region β42 are joined three or more times in the order of region α41, region β42, region α41, region β42, region α41. Having such a cross-section in the composite fiber results in a thin, high-strength artificial leather. This is because the amount of extrusion per single pore during composite spinning, which will be described later, can be increased, thereby suppressing yarn breakage when spinning at high speed and resulting in a high-strength composite fiber.

[0057] Furthermore, the composite fibers according to this embodiment may contain pigments. The artificial leather containing pigments will also have excellent lightfastness. Examples of these pigments include both inorganic and organic pigments. Examples of inorganic pigments include black pigments such as carbon black, blue pigments such as ultramarine blue and prosciuta blue (potassium iron ferrocyanide), red pigments such as red lead and iron oxide red, and yellow pigments such as lead yellow and zinc yellow (zinc yellow type 1, zinc yellow type 2). Examples of organic pigments include condensed polycyclic organic pigments such as phthalocyanine, anthraquinone, quinacridone, dioxazine, isoindolinone, isoindoline, indigo, quinophthalone, diketopyrrolopyrrole, perylene, and perinone, as well as insoluble azo pigments such as benzimidazolon, condensed azo, and azomethine azo. These may be used individually or in combination of two or more.

[0058] Furthermore, when the composite fiber according to this embodiment contains a pigment, it is preferable that the area ratio of the pigment to the cross-section of the composite fiber is in the range of 0.01% to 13.00%. A lower limit of this area ratio is preferably 0.01% or more, more preferably 0.05% or more, and even more preferably 0.10% or more, resulting in a darker colored artificial leather. On the other hand, a higher upper limit of the content is 13.00% or less, more preferably 11.00% or less, and even more preferably 10.00% or less, resulting in a higher-strength artificial leather.

[0059] In this embodiment, the area ratio of pigment in the composite fiber (when measured and calculated from artificial leather) is measured and calculated by the following method: (i) Ten 1 cm x 1 cm test pieces are randomly cut from the artificial leather. (ii) The cross-section of the test piece is photographed at a magnification of 200x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation), and in the captured SEM image, a virtual line (181 in Figure 1, hereafter simply abbreviated as virtual line 181) passing through the tip of the pile portion or the edge of the resin portion is drawn using the method described above, and a virtual line (182 in Figure 1, hereafter simply abbreviated as virtual line 182) passing through the edge of the other surface is drawn using the method described above. Next, the distances of 25% and 35% of the distance between virtual line 181 and virtual line 182 are determined, and the portion P of the test piece is determined. Ｃ Determine the following: (iii) Part P of the test specimen Ｃ (iv) Randomly select 10 fibers from the cross-section perpendicular to the thickness direction. (iv) Take images of the cross-sections of the selected fibers using a scanning electron microscope (SEM, e.g., Keyence Corporation's "VHX-D510") at a magnification of 10,000x. However, if the entire cross-section of the fibers does not fit into one field of view, take five random fields of view per fiber. (v) Use image analysis software (e.g., "ImageJ") to measure the area of ​​the fiber cross-section and the area of ​​the pigment portion. (vi) For all fields measured in (iv) above, calculate the area ratio of the pigment portion to the area of ​​the fiber cross-section using the following formula, and calculate the arithmetic mean (%) of the obtained pigment area ratios. Pigment area ratio (%) = (Total area of ​​pigment portion [μm²] ２ ]) / (Area of ​​fiber cross-section [μm²] ２ ]) × 100 ... (formula) (vii) Repeat (iv) to (vi) in the same way for the other 9 fibers to calculate the area ratio of pigment for all fibers. (viiii) Repeat (ii) to (vii) in the same way for the other 9 test pieces to calculate the arithmetic mean (%) of the area ratio of pigment for all fibers (100 fibers) of all test pieces, and round to the third decimal place.

[0060] [Long Fiber Nonwoven Fabric] The long fiber nonwoven fabric according to this embodiment is composed of the thermoplastic resin fibers described above. In other words, in the artificial leather according to this embodiment, the thermoplastic resin fibers are long fibers. Being long fibers not only results in artificial leather with high mechanical strength, but also makes it difficult for the thermoplastic resin fibers to detach from the artificial leather, resulting in artificial leather with good abrasion resistance. Here, in this embodiment, "long fiber" means substantially continuous fibers with a fiber length of 100 mm or more, not short fibers that have been intentionally cut after spinning. More specifically, it means fibers that have not been intentionally cut to a fiber length of approximately 3 mm to 80 mm. However, in the process of manufacturing artificial leather, for example, fibers at the ends formed when a sheet is slit, or surface fibers that are formed when nap is created on the surface of the sheet, are considered long fibers even if they have been cut to a certain length.

[0061] Examples of such long-fiber nonwoven fabrics include spunbond nonwoven fabrics and meltblown nonwoven fabrics. In particular, if the long-fiber nonwoven fabric is a spunbond nonwoven fabric, it is more preferable because it results in a stronger artificial leather. On the other hand, if the long-fiber nonwoven fabric is a meltblown nonwoven fabric, it is also more preferable because it results in an artificial leather with superior flexibility.

[0062] [Artificial Leather] The artificial leather of this embodiment includes the long-fiber nonwoven fabric described above. The artificial leather of this embodiment has a napped portion and / or a resin layer on one of its surfaces. Here, in the artificial leather of the present invention, a surface having a "nailed portion" refers to a surface having a napped layer of ultrafine fibers that is flexible in the direction of the finger tracing to such an extent that a so-called lighting effect is produced when the surface is traced with a finger. Having such a napped portion allows it to be used as an artificial leather with an elegant appearance like suede or nubuck. Of course, depending on the desired purpose, only one surface on one side of the artificial leather may have a napped surface, or both surfaces may have a napped surface.

[0063] In the case where the surface of the artificial leather according to this embodiment has a pile, it is more preferable that the number of fiber ends (hereinafter sometimes abbreviated as "surface fiber end count") observed from a 200 μm square field of view of the surface having the pile is 4 or more. A larger surface fiber end count means a larger pile, and when the surface fiber end count is preferably 4 or more, more preferably 7 or more, and even more preferably 10 or more, the artificial leather has an elegant suede-like or nubuck-like appearance. Generally, the upper limit is about 600, and preferably 100 or less results in an artificial leather with a smooth surface touch.

[0064] In this invention, the number of surface fiber ends is measured and calculated by the following method: (i) Five 2cm x 2cm test pieces are randomly cut out. (ii) The pile surface of the test pieces is made to stand up using a lint brush or the like, and the pile surface is photographed at 500x magnification in three locations using a scanning electron microscope (for example, the "VHX-D510" manufactured by Keyence Corporation). (iii) A 200 μm square field of view is randomly extracted from the captured images, and the number of fiber ends is counted. Here, "fiber end" refers to the end of a fiber that is observed in an independent state. However, if the end of a fiber is attached to other fibers aligned in the same direction and appears as one, it is not counted as a fiber end. (iv) The arithmetic mean (number of fibers) obtained from all the captured images is calculated and rounded to the first decimal place.

[0065] In the case where the surface of the artificial leather according to this embodiment has a pile, it is preferable that the length of the pile in the pile, i.e., the pile length, is 20 μm or more and 200 μm or less. When the pile length is preferably 30 μm or more, and more preferably 50 μm, the artificial leather has a smooth surface touch. On the other hand, when the pile length is preferably 180 μm or less, and more preferably 150 μm, the artificial leather has less change in appearance when used for a long period of time.

[0066] The pile length is measured and calculated by the following method: (i) Using a lint brush or the like, the pile of the artificial leather is raised, and a thin section with a thickness of 1 mm is prepared in the cross-sectional direction of a surface perpendicular to the longitudinal direction of the artificial leather. (ii) The cross-section of the artificial leather is photographed at 100x magnification using a scanning electron microscope (SEM, for example, "VHX-D510" manufactured by Keyence Corporation). (iii) In the captured SEM image, a virtual line 551 is drawn passing through the tip 53 of the pile portion 51, as illustrated in the conceptual cross-sectional diagram of the artificial leather shown in Figure 5, and this is used as the reference line for one surface. Similarly, a virtual line 552 is drawn passing through the end 54 of the other surface of the artificial leather, and this is used as the reference line for the other surface. The virtual lines 551 and 552 are to be parallel straight lines, and the distance between the virtual lines 551 and 552 is to be maximized. Then, according to the schematic diagram of the cross-section of the artificial leather shown in Figure 5, perpendicular lines S are drawn on the imaginary line 551 at intervals of 200 μm. １ ~S １０ Draw a line. (iv) The boundary line between the upright portion 51 and the base portion 52 and the perpendicular line S １ Point P is the point where they intersect. １ The tip of the upright portion 51 and the perpendicular line S １ Q is at the point where they intersect. １ Mark each of them. (v) Similarly, the perpendicular S ２ ~S １０ Point P is above. ２ ~P １０ , point Q ２ ~Q １０ Mark each of them. (vi) Point P １ and Q １ Distance R １ (Head length) and similarly R １０ We calculate up to that point and then calculate the average value (arithmetic mean).

[0067] Furthermore, the pile length can be adjusted by the grit size and amount of sanding used during the pile-raising process by sandpaper grinding.

[0068] Furthermore, it is preferable that the artificial leather of this embodiment has a resin layer on one surface. Such artificial leather may be, for example, as illustrated in Figure 6, in which substantially the entire surface of the side having the pile portion 61 is covered with a resin layer 63 (so-called grain-like artificial leather), or as illustrated in Figure 7, in which a part of the surface of the side having the pile portion 71 is covered with a resin layer 73 (so-called semi-grain-like artificial leather). It is also preferable that the resin layer is given a pattern such as a grain similar to that of natural leather. In any case, since the artificial leather of this embodiment contains the crimped fibers, it is less likely to wrinkle even when the artificial leather is deformed, and it can maintain a high-quality appearance even after molding.

[0069] In this embodiment, the case in which a portion of the surface of the side having the pile is covered with a resin layer (so-called semi-grain artificial leather), that is, the case in which a resin layer is discretely provided on the surface having the pile, refers to a configuration in which the resin layer is arranged in a grid pattern, houndstooth pattern, twill weave pattern, satin weave pattern, random pattern, etc., as described later. The shape of the resin layer can be various shapes depending on the application, such as circles, stars, hearts, triangles, squares, hexagons, octagons, and other polygons. Of course, in the present invention, the arrangement and shape of the discretely provided resin layer are not particularly limited.

[0070] The resin of the resin layer according to this embodiment can be, for example, polyurethane resins such as "polyether-based polyurethane resin, polyester-based polyurethane resin, polycarbonate-based polyurethane resin, acrylic-based polyurethane resin," polyurea, elastomer, polyacrylic acid, acrylonitrile-butadiene elastomer and styrene-butadiene elastomer, polyvinyl chloride, etc., and may be a single resin or a mixture of two or more resins. Furthermore, if the resin of the resin layer is a polyurethane resin, the polyurethane resin may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. Among these resin layers, polyurethane is preferably used from the viewpoint of flexibility and cushioning.

[0071] Also, the thickness of the resin layer according to this embodiment is preferably 30 μm or more and 200 μm or less. When the thickness of the resin layer is preferably 30 μm or more, more preferably 50 μm or more, and even more preferably 70 μm or more, artificial leather with good abrasion resistance of the resin layer can be obtained. On the other hand, when the thickness of the resin layer is preferably 200 μm or less, more preferably 180 μm or less, and even more preferably 150 μm or less, artificial leather with a soft texture can be obtained.

[0072] In this embodiment, the thickness of the resin layer is measured by taking a scanning electron microscope (SEM) photograph of the cross-section of the artificial leather, randomly measuring the thickness of the resin layer at 10 locations, calculating the arithmetic mean value (μm), and rounding it to the first decimal place.

[0073] And the artificial leather of this embodiment satisfies the following formulas (1) to (4): 1.4 × φ ＰＳ１ ≤ φ ＰＣ ≤ 4.0 × φ ＰＳ１ ... (Formula 1) 0.05 ≤ r ＰＳ１ ≤ 0.20... (Formula 2) 0.05 ≤ r ＰＳ２ ≤ 0.20... (Formula 3) 0.05 ≤ r ＰＣ ≤ 0.20... (Formula 4) Here, φ ＰＳ１ is the average equivalent circle diameter (μm) of the thermoplastic resin fibers in the portion P Ｓ１ , φ ＰＣ is the average equivalent circle diameter (μm) of the thermoplastic resin fibers in the portion P Ｃ , r ＰＳ１ is the curvature of the thermoplastic resin fibers in the portion P Ｓ１ , r ＰＣ is the curvature of the thermoplastic resin fibers in the portion P Ｃ , r ＰＳ２ is the curvature of the thermoplastic resin fibers in the portion P Ｓ２ . By satisfying these Formulas (1) to (4), artificial leather with an elegant and high-class appearance, high strength, and excellent flexibility can be obtained. Hereinafter, each will be described in more detail.

[0074] First, the artificial leather according to this embodiment satisfies the above formula 1. With respect to this formula 1, φ ＰＣ However, 1.4 × φ ＰＳ１ (1.4 × φ ＰＳ１ ≦φ ＰＣ Preferably, 2.0 × φ ＰＳ１ (2.0 × φ ＰＳ１ ≦φ ＰＣ ) results in a highly flexible artificial leather. On the other hand, with respect to formula 1, φ ＰＣ However, 4.0 × φ ＰＳ１ Below (φ ＰＣ ≤4.0 × φ ＰＳ１ Preferably, 3.5 × φ ＰＳ１ Below (φ ＰＣ ≤3.5 × φ ＰＳ１ This results in artificial leather with a smoother feel.

[0075] In this embodiment, the average equivalent diameter of the thermoplastic resin fibers is φ. ＰＳ１ , φ ＰＣ (μm) is measured and calculated by the following method: (i) Cut out five 2cm x 2cm test pieces. (ii) Of the cross-sections of the test pieces, the portion P Ｓ１ (iii) Take an image of the cross-section at a magnification of 3000x using a scanning electron microscope (for example, the "VHX-D510" manufactured by Keyence Corporation). (iii) Measure the cross-sectional area of ​​each of the 10 randomly selected fibers at 10 locations. (iv) Perform (ii) to (iii) for all test pieces, convert the obtained average cross-section to the equivalent diameter (μm) of a perfect circle, and round the arithmetic mean (μm) of the equivalent diameter to two decimal places to obtain the value φ ＰＳ１ (v) Similarly, the portion P Ｃ The average equivalent diameter of a circle measured by φ ＰＣ Let's assume that.

[0076] Furthermore, the average equivalent diameter of this thermoplastic resin fiber is φ ＰＳ１ , φ ＰＣ This can be adjusted by controlling the amount of resin discharged during spinning and the spinning speed of the resin.

[0077] Next, the artificial leather according to this embodiment satisfies the above formulas 2 to 4. That is, the curvature r of the thermoplastic resin fiber ＰＳ１ ,rＰＣ ,r ＰＳ２ (All values ​​are unitless) However, it is important that all values ​​are between 0.05 and 0.20 in order to produce artificial leather with excellent flexibility and strength. Curvature r ＰＳ１ ,r ＰＣ ,r ＰＳ２ However, in all cases, 0.05 or greater (0.05 ≤ r ＰＳ１ ,r ＰＣ ,r ＰＳ２ Preferably 0.06 or more (0.06 ≤ r ＰＳ１ ,r ＰＣ ,r ＰＳ２ ), more preferably 0.07 or more (0.07 ≤ r ＰＳ１ ,r ＰＣ ,r ＰＳ２ ) This results in a more flexible texture for the artificial leather. On the other hand, the curvature r ＰＳ１ ,r ＰＣ ,r ＰＳ２ However, in all cases, 0.20 or less (r ＰＳ１ ,r ＰＣ ,r ＰＳ２ ≤ 0.20), preferably 0.18 or less (r ＰＳ１ ,r ＰＣ ,r ＰＳ２ ≤0.18), more preferably 0.16 or less (r ＰＳ１ ,r ＰＣ ,r ＰＳ２ Having a tensile strength of ≤0.16 results in artificial leather with higher tensile strength.

[0078] The curvature r of the thermoplastic resin fiber ＰＳ１ ,r ＰＣ ,r ＰＳ２(All values ​​are unitless) are measured and calculated by the following method: (i) Cut out four 1 cm x 1 cm test pieces randomly from the artificial leather. (ii) Photograph the cross-section of the test piece at a magnification of 200x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). In the captured SEM image, draw a virtual line passing through the tip of the pile or the edge of the resin part (181 in Figure 1, hereafter simply abbreviated as virtual line 181) and a virtual line passing through the edge of the other surface (182 in Figure 1, hereafter simply abbreviated as virtual line 182) using the method described above. Next, find the 5% distance of the distance between virtual line 181 and virtual line 182. (iii) The specimen is embedded in epoxy resin, and using a cryomicrotome (e.g., Leica's "Ultracut-UCT"), a portion of the specimen P is cut from the surface having the pile or resin portion, at the distance determined in (ii), and a portion of the specimen P is obtained. Ｓ１ A precise cross-section perpendicular to the thickness direction is prepared. (iv) Part P of the test specimen Ｓ１ A precise cross-section perpendicular to the thickness direction is imaged at a magnification of 300x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). (v) Five fibers are randomly selected from the captured SEM image. (vi) As shown in Figure 8, the distance L between a 100 μm long chord 84, which is parallel to the baseline 83 that is in contact with the two curved parts opposite to the vertex 82 of the fiber 81, and the vertex 82 is measured, and the curvature is calculated using the following formula.

[0079] Curvature (unitless) = L (μm) / 100 (μm) ... (formula) (vii) The same measurement is performed on the other test pieces, and the curvature is determined for all fibers. The arithmetic mean (unitless) of the obtained values ​​is rounded to the third decimal place and the value obtained is r ＰＳ１ (Unitless) (viiii) Similarly, a portion of the specimen P is cut to a distance of 30% of the distance between virtual lines 181 and 182. Ｃ A precise cross-section perpendicular to the thickness direction, and a portion of the test specimen P cut to a distance of 95% of the distance between virtual lines 181 and 182. Ｓ２ A precise cross section perpendicular to the thickness direction is fabricated, and the curvature r ＰＣ,r ＰＳ２ Measure and calculate each of the following (all units are void):

[0080] Furthermore, the above φ ＰＳ１ However, it is preferable that it be between 2.0 μm and 10.0 μm. Average equivalent circle diameter φ ＰＳ１ Regarding the lower limit of the range, preferably 2.0 μm or more, more preferably 2.5 μm or more, and even more preferably 3.0 μm or more, the artificial leather becomes less prone to wrinkles and stretching, and less likely to lose its shape when molded. On the other hand, regarding the upper limit of the range of the average equivalent circle diameter, preferably 10.0 μm or less, more preferably 8.0 μm or less, and even more preferably 5.0 μm or less, the artificial leather has a superior tactile feel.

[0081] Furthermore, the aforementioned portion P Ｓ２ , P Ｃ The equivalent circular diameter of the fiber in φ ＰＳ２ , φ ＰＣ It is preferable that the following equation 5 is satisfied.

[0082] 1.4 × φ ＰＳ２ ≦φ ＰＣ ≤4.0 × φ ＰＳ２ ... (Equation 5) Here, φ ＰＳ２ is the aforementioned part P Ｓ２ The average equivalent diameter (μm) of the thermoplastic resin fibers in φ ＰＣ is the aforementioned part P Ｃ This is the average equivalent diameter (μm) of the thermoplastic resin fibers in the given equation. With respect to this equation 5, φ ＰＣ However, 1.4 × φ ＰＳ２ (1.4 × φ ＰＳ２ ≦φ ＰＣ Preferably, 2.0 × φ ＰＳ２ (2.0 × φ ＰＳ２ ≦φ ＰＣ ) results in a highly flexible artificial leather. On the other hand, with respect to formula 1, φ ＰＣ However, 4.0 × φ ＰＳ２ Below (φ ＰＣ ≤4.0 × φ ＰＳ２ Preferably, 3.5 × φ ＰＳ２ Below (φ ＰＣ ≤3.5 × φ ＰＳ２This results in artificial leather with a smoother feel.

[0083] Alternatively, the aforementioned part P Ｓ２ , P Ｃ The equivalent circular diameter of the fiber in φ ＰＳ２ , φ ＰＣ It is also preferable that the following equation 6 is satisfied.

[0084] 0.8 × φ ＰＳ２ ≦φ ＰＣ ≤ 1.2 × φ ＰＳ２ ... (Equation 6) Here, φ ＰＳ２ , φ ＰＣ The same applies as described above.

[0085] φ ＰＣ And, φ ＰＳ２ The ratio of the equivalent diameter of the circle within this range results in artificial leather with superior mechanical strength.

[0086] In this embodiment, the average equivalent diameter of the thermoplastic resin fibers is φ. ＰＳ２ The average circular equivalent diameter of the thermoplastic resin fiber is φ ＰＣ (μm) is measured and calculated in the same manner as the measurement and calculation method, and the part P Ｓ２ The average equivalent diameter of a circle measured by φ ＰＳ２ This is the conclusion.

[0087] Furthermore, the average equivalent diameter of this thermoplastic resin fiber is φ ＰＳ２ This can be adjusted by controlling the amount of resin discharged during spinning and the spinning speed of the resin.

[0088] Furthermore, the artificial leather of this embodiment is the part P Ｃ In the thermoplastic resin fiber, it is preferable that the region α and the region β are connected three or more times in the order of region α, region β, region α, region β... In other words, as will be described later, the portion P Ｃ In the above, the number of connected thermoplastic resin fibers N ＣIt is preferable that the number is 3 or more. As will be described later, the number of connections is the number of regions β in the portion where the regions α and β are connected in the order of region α, region β, region α, region β... In the case of a chain of connections, the number of connections is the number of regions β that exist up to the starting region α, counting clockwise from any region α. ​​Therefore, in the thermoplastic resin fiber cross-section illustrated in Figure 9, the number of connections is 12 in the case of 91a and 3 in the case of 91b.

[0089] By adopting such a structure, the amount of fiber discharged per single pore during spinning can be increased, thereby suppressing fiber breakage during high-speed spinning and thus improving spinning productivity.

[0090] In this embodiment, the portion P Ｃ The number of connections between region α and region β in the above region N Ｃ This is measured and calculated by the following method. Other parts (part P) Ｓ１ , part P Ｓ２ ) Number of connections (each, N Ｓ１、 N Ｓ２ The same applies to (i) the portion P Ｃ (ii) From the elastic modulus images of two regions in the same field of view, the number of regions β in the connected region α, region β, region α, region β, region β, etc. is determined. In the case of a chain of connected regions, the number of regions β is determined by starting from any region α and counting clockwise until the starting region α is returned. (iii) Repeat this process for the remaining two fields of view, and the arithmetic mean of the average number of connected regions α in the three fields of view is rounded to the first decimal place.

[0091] Furthermore, the artificial leather of this embodiment may also preferably contain polyurethane resin. The inclusion of polyurethane resin results in artificial leather with a moderate degree of resilience when gripped. Preferably, the polyurethane used is obtained by the reaction of a polymer diol, an organic diisocyanate, and a chain extender.

[0092] The polymer diol used in the polyurethane resin according to the present invention can be at least one polymer diol selected from polymer diols such as polyester diol, polyether diol, polycarbonate diol, or polyester polyether diol, all having an average molecular weight of 500 to 3000. However, it is preferable that the polyurethane resin contains a polyether diol or polycarbonate diol, which has excellent hydrolysis resistance and does not easily impair the binder's function against repeated washing.

[0093] Furthermore, the polyurethane resin according to this embodiment may contain various additives depending on the purpose, such as pigments like carbon black, flame retardants such as phosphorus-based, halogen-based, and inorganic types, antioxidants such as phenol-based, sulfur-based, and phosphorus-based types, ultraviolet absorbers such as benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based, and oxalic acid anilide-based types, light stabilizers such as hindered amine-based and benzoate-based types, hydrolysis-resistant stabilizers such as polycarbodiimide, plasticizers, antistatic agents, surfactants, coagulation modifiers, and dyes.

[0094] Generally, the polyurethane resin content in artificial leather can be adjusted as appropriate, taking into consideration the type of polyurethane resin used, the method of manufacturing the polyurethane resin, and the desired texture and physical properties of the artificial leather. However, in the artificial leather of this embodiment, it is preferable that the polyurethane resin content is 5% by mass or more and 20% by mass or less. A lower limit of 5% by mass or more, and more preferably 8% by mass or more, in the range of polyurethane resin content results in artificial leather with high abrasion resistance. On the other hand, an upper limit of 20% by mass or less, more preferably 15% by mass or less, and even more preferably 12% by mass or less, in the range of polyurethane resin content results in artificial leather with higher flexibility.

[0095] In this invention, the polyurethane resin content in artificial leather refers to the value measured and calculated by the following methods: (i) Cut out five 2cm x 2cm test pieces and measure the mass of each test piece. When cutting out test pieces from a product made of artificial leather, randomly select a portion of the product excluding seams and embossed areas, and use it after adjusting it to standard conditions of 20±2°C and 65±4% relative humidity. (ii) Immerse the artificial leather in a solvent that elutes ultrafine fibers and reinforcing fibers, or a solvent that elutes polyurethane resin, and calculate the polyurethane resin content (g) from the change in mass before and after elution. For example, in the case of artificial leather containing organic solvent-based polyurethane resin, the polyurethane resin content (g) is often calculated by immersing the artificial leather in N,N'-dimethylformamide to dissolve and remove the polyurethane resin, and then measuring the mass of the remaining ultrafine fibers and reinforcing fibers. (iii) Divide the polyurethane resin content obtained in (iii) by the mass (g) of the test piece obtained in (i) to calculate the polyurethane resin content percentage (mass%). (iv) Perform (ii) to (iii) for all test pieces, calculate the arithmetic mean (mass%) of the obtained polyurethane resin content percentages (mass%), and round to the first decimal place.

[0096] Furthermore, the polyurethane resin according to this embodiment may contain a pigment. Examples of such pigments include those described as pigments for thermoplastic resin fibers.

[0097] Furthermore, when the polyurethane resin according to this embodiment contains a pigment, it is preferable that the total pigment content in the polyurethane resin is in the range of 0.1% by mass or more and 10.0% by mass or less. Within this content range, a lower limit of preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more results in a darker colored artificial leather. On the other hand, within this content range, an upper limit of 10.0% by mass or less, more preferably 9.0% by mass or less, and even more preferably 8.0% by mass or less results in a higher strength artificial leather.

[0098] In this embodiment, the total pigment content in the polyurethane resin is measured and calculated by the following method: (i) a total of 1 m from the artificial leather ２ (ii) Randomly cut out test specimens and measure their mass. When cutting out test specimens from products containing artificial leather, randomly select specimens from areas excluding seams and embossed parts of the product, and adjust them to standard conditions of 20±2°C and 65±4% relative humidity before use. (ii) Immerse the test specimens thoroughly in a solvent that elutes polyurethane resin to elute the polyurethane resin. Then, determine the polyurethane resin content w from the change in mass before and after elution. Ｕ (g) is calculated. For example, in the case of artificial leather containing organic solvent-based polyurethane resin, the test piece is often immersed in N,N'-dimethylformamide to dissolve and remove the polyurethane resin, and then the mass (g) of the remaining ultrafine fibers and other reinforcing fibers is measured to calculate the total content (g) of polyurethane resin and the pigment contained in the polyurethane resin. (iii) The remaining ultrafine fibers are ultrasonically cleaned, and the washing solution is filtered to recover the pigment in the polyurethane resin attached to the ultrafine fibers. The mass of the recovered pigment is measured and this is w Ｐ１ (g) (iv) The pigment in the polyurethane resin that has come out of the artificial leather along with the polyurethane resin is recovered by filtering the eluted polyurethane resin. The mass of the recovered pigment is measured and this is w Ｐ２ (g) The mass w of the pigment obtained by (v) (iii) and (iv) Ｐ１ (g), w Ｐ２By summing up (g), the amount of pigment in the polyurethane resin is w Ｐ (g) is calculated. In this invention, the pigment content in the polyurethane resin is calculated by the following formula: Pigment content (%) = w Ｐ / (w Ｕ +w Ｐ ) × 100 ... (formula) Perform (vi), (ii) to (v) for all test pieces, calculate the arithmetic mean (mass%) of the pigment content (mass%) of the obtained polyurethane resin, and round it to the third decimal place.

[0099] [Method for Manufacturing Artificial Leather] The method for manufacturing artificial leather according to this embodiment preferably includes the steps of: discharging a thermoplastic resin from the discharge hole of a die, blowing gas to form a yarn including at least a part of the area within 200 mm from the discharge hole, and pulling at a spinning speed of 3000 m / min to 7000 m / min to form thermoplastic resin fibers; collecting the thermoplastic resin fibers to form a fiber web; heat treating the fiber web at 70°C to 250°C to form a crimped fiber web from the thermoplastic resin fibers to crimped fibers; and polishing or entangling at least one surface of the crimped fiber web with water. Details of each step will be described below. Of course, even in this part, the present invention is not limited in any way to the scope described below as long as it does not exceed the gist of the present invention, and it goes without saying that various modifications are possible without departing from the gist of the present invention.

[0100] <Process for forming thermoplastic resin fibers> In this process, thermoplastic resin is extruded from the discharge hole of the die, and then gas is blown to form a yarn, including at least a portion of the area within 200 mm from the discharge hole. The yarn is then pulled at a spinning speed of 3000 m / min to 7000 m / min to form thermoplastic resin fibers.

[0101] First, thermoplastic resin is dispensed from the discharge hole of the nozzle. At this time, the discharge hole of the nozzle is in section P. Ａ and section P Ｂ It is preferable that these be arranged alternately. In particular, as illustrated in Figure 10, section P Ａand section P Ｂ It is preferable to discharge from nozzles that are alternately arranged on the circumference (in Figure 10, section P Ｂ 102B is filled in with a pattern, but this is not intended to indicate that it is solid, and section P Ａ (It is filled with a pattern to distinguish it from 102A.)

[0102] In addition, section P Ａ From there, it is preferable to extrude a thermoplastic resin A having an elastic modulus of 15 MPa or more and 400 MPa or less at 25°C as measured by an atomic force microscope, and the section P Ｂ It is preferable to extrude a thermoplastic resin B from which the elastic modulus at 25°C, as measured by an atomic force microscope, is 1000 MPa or more and 5000 MPa or less.

[0103] In this process, the "thermoplastic resin A having an elastic modulus of 15 MPa or more and 400 MPa or less at 25°C as measured by an atomic force microscope" or the "thermoplastic resin B having an elastic modulus of 1000 MPa or more and 5000 MPa or less at 25°C as measured by an atomic force microscope" can be a thermoplastic elastomer resin in region α or a polyester resin in region β, respectively.

[0104] This thermoplastic resin A also has a melting point T ｍ、Ａ The melting point (°C) is preferably between 140°C and 240°C. ｍ、Ａ Regarding the lower limit of the range (°C), its melting point T ｍ、Ａ When the melting point (°C) is preferably 140°C or higher, more preferably 150°C or higher, and even more preferably 160°C or higher, it is possible to obtain artificial leather that is less prone to deformation during the dyeing process described later and has a uniform texture. On the other hand, this melting point T ｍ、Ａ Regarding the upper limit of the range (°C), its melting point T ｍ、Ａ When the temperature (°C) is preferably 240°C or lower, more preferably 230°C or lower, and even more preferably 220°C or lower, the resin is easily melted in the sheet substrate formation process described later, and an artificial leather is obtained that has both a moderate rebound and flexibility when gripped.

[0105] Furthermore, thermoplastic resin B has a melting point T ｍ、Ｂ The melting point (°C) is preferably 200°C or higher and 300°C or lower. ｍ、Ｂ Regarding the lower limit of the range (°C), its melting point T ｍ、Ｂ When the melting point (°C) is preferably 200°C or higher, more preferably 210°C or higher, and even more preferably 220°C or higher, it is possible to obtain artificial leather that is less prone to deformation during the dyeing process described later and has a uniform texture. On the other hand, this melting point T ｍ、Ｂ Regarding the upper limit of the range (°C), its melting point T ｍ、Ｂ Preferably, the temperature is 300°C or lower, more preferably 290°C or lower, and even more preferably 280°C or lower. This allows the resin to be sufficiently cooled between the discharge hole of the nozzle (described later) and the inlet of the ejector, resulting in stable spinnability and the production of uniformly textured artificial leather.

[0106] On the other hand, the melting point T of thermoplastic resin A ｍ、Ａ (°C) represents the melting point T of thermoplastic resin B. ｍ、Ｂ It is preferable that the temperature is 20°C or more and 100°C lower than (°C). In other words, the difference T ｍ、Ｂ -T ｍ、Ａ It is preferable to set the temperature (°C) to 20°C or higher and 100°C or lower. By setting the difference range to preferably 20°C or higher, and more preferably 40°C or higher, in the sheet substrate formation process described later, only the thermoplastic resin A and thermoplastic resin B with the lower melting point can be easily heat-fused, thereby obtaining artificial leather that has both appropriate resilience and flexibility when gripped. On the other hand, by setting the temperature to preferably 100°C or lower, and more preferably 80°C or lower, the thermal decomposition of the low-melting-point resin during spinning can be suppressed, and artificial leather with excellent mechanical properties can be obtained.

[0107] Furthermore, in this process, a pigment may be added to the thermoplastic resin A and / or the thermoplastic resin B. Examples of such pigments include those described as pigments for the thermoplastic resin fibers.

[0108] Furthermore, when a pigment is added to the thermoplastic resin A and / or the thermoplastic resin B according to this embodiment, it is preferable that the area ratio of the pigment in the thermoplastic resin fibers be in the range of 0.01% to 13.00%. By setting the lower limit of this area ratio range to preferably 0.01% or more, more preferably 0.05% or more, and even more preferably 0.10% or more, a darker colored artificial leather is obtained. On the other hand, by setting the upper limit of the area ratio range to 13.00% or less, more preferably 11.00% or less, and even more preferably 10.00% or less, a higher strength artificial leather is obtained.

[0109] In this embodiment, the area ratio of the pigment in the thermoplastic resin fiber (when measured and calculated from the thermoplastic resin fiber) is measured and calculated by the following method: (i) Ten 1 cm × 1 cm test pieces are randomly cut from the artificial leather. (ii) The cross-section of the test piece is photographed at a magnification of 200x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation), and in the captured SEM image, a virtual line (181 in Figure 1, hereafter simply abbreviated as virtual line 181) passing through the tip of the pile portion or the edge of the resin portion is drawn using the method described above, and a virtual line (182 in Figure 1, hereafter simply abbreviated as virtual line 182) passing through the edge of the other surface is drawn using the method described above. Next, the distances of 25% and 35% of the distance between virtual line 181 and virtual line 182 are determined, and the portion P of the test piece is determined. Ｃ Determine the following: (iii) Part P of the test specimen Ｃ(iv) Randomly select 10 fibers from the cross-section perpendicular to the thickness direction. (iv) Take images of the cross-sections of the selected fibers using a scanning electron microscope (SEM, e.g., Keyence Corporation's "VHX-D510") at a magnification of 10,000x. However, if the entire cross-section of the fibers does not fit into one field of view, take five random fields of view per fiber. (v) Use image analysis software (e.g., "ImageJ") to measure the area of ​​the fiber cross-section and the area of ​​the pigment portion. (vi) For all fields measured in (iv) above, calculate the area ratio of the pigment portion to the area of ​​the fiber cross-section using the following formula, and calculate the arithmetic mean (%) of the obtained pigment area ratios. Pigment area ratio (%) = (Total area of ​​pigment portion [μm²] ２ ]) / (Area of ​​fiber cross-section [μm²] ２ ]) × 100 ... (formula) (vii) Repeat (iv) to (vi) in the same way for the other 9 fibers to calculate the area ratio of pigment for all fibers. (viiii) Repeat (ii) to (vii) in the same way for the other 9 test pieces to calculate the arithmetic mean (%) of the area ratio of pigment for all fibers (100 fibers) of all test pieces, and round to the third decimal place.

[0110] Furthermore, in this process, the section P at the time of discharge Ａ The discharge volume per section (hereinafter referred to simply as "section P") Ａ It may be described as "single-compartment discharge rate".) Preferably, the discharge rate is 0.01 g / (min / compartment) or more and 0.13 g / (min / compartment) or less, and the discharge rate of compartment P Ｂ The discharge volume per section (hereinafter referred to simply as "section P") Ｂ It is sometimes described as "single-section discharge amount".) Preferably, the amount is 0.05 g / (min / section) or more and 0.20 g / (min / section) or less. By doing so, it is possible to obtain artificial leather with a uniform texture, a good surface touch, and appropriate rebound when gripped. Here, section P at the time of discharge Ａ The discharge rate per section (g / (min / section)) is given by section P Ａ This refers to the amount of resin (g) discharged per minute from one section. And, section P during discharge. ＢThe discharge rate per section (g / (min / section)) is given by section P Ｂ This refers to the amount of resin (g) dispensed per minute from one section. A section refers to a single dispensing hole provided in the nozzle to obtain an independent area of ​​resin, as illustrated in Figures 92 and 93.

[0111] First, section P Ａ Regarding the lower limit of the single-compartment discharge rate range, compartment P Ａ By setting the single-section discharge rate to preferably 0.01 g / (min / section) or more, more preferably 0.02 g / (min / section) or more, and even more preferably 0.03 g / (min / section) or more, stable spinnability can be obtained as long as thermoplastic resin fibers are formed within the range of spinning speeds described later, and artificial leather with a uniform texture can be obtained. On the other hand, section P Ａ Regarding the upper limit of the single-compartment discharge rate range, compartment P Ａ By setting the single-section discharge rate to preferably 0.13 g / (min / section) or less, more preferably 0.10 g / (min / section) or less, and even more preferably 0.07 g / (min / section) or less, an artificial leather with a surface touch and appropriate resilience when gripped can be obtained, as long as thermoplastic resin fibers are formed within the range of spinning speeds described later.

[0112] Meanwhile, section P Ｂ Regarding the lower limit of the single-compartment discharge rate range, compartment P Ｂ By setting the single-section discharge rate to preferably 0.05 g / (min / section) or more, more preferably 0.07 g / (min / section) or more, and even more preferably 0.10 g / (min / section) or more, stable spinnability can be obtained as long as thermoplastic resin fibers are formed within the range of spinning speeds described later, and artificial leather with a uniform texture can be obtained. On the other hand, section P Ａ Regarding the upper limit of the single-compartment discharge rate range, compartment P Ａ By setting the single-section discharge rate to preferably 0.20 g / (min / section) or less, more preferably 0.17 g / (min / section) or less, and even more preferably 0.14 g / (min / section) or less, an artificial leather with a surface touch and appropriate resilience when gripped can be obtained, as long as thermoplastic resin fibers are formed within the range of spinning speeds described later.

[0113] Furthermore, in this process, the total amount of thermoplastic resin A discharged from a single section (all sections P) Ａ This is the discharge volume, (partition P Ａ (Single-section discharge volume) × (Section P Ａ It can be calculated by the number of sections.) and the sum of the single-section discharge amounts of thermoplastic resin B (all sections P B This is the discharge volume of the section, (section P Ｂ (Single-section discharge volume) × (Section P Ｂ It can be calculated by the number of sections. The ratio of sections is preferably 8:92 to 40:60, more preferably 15:85 to 35:65, and even more preferably 20:80 to 30:70. As the single-section discharge amount of thermoplastic resin A is increased, an artificial leather with an elegant and high-quality appearance and excellent deformability that can conform to complex shapes such as vehicle parts can be obtained. On the other hand, as the single-section discharge amount of thermoplastic resin B is increased, an artificial leather with high tensile strength and excellent abrasion resistance can be easily obtained.

[0114] As described above, after discharging the thermoplastic resin from the nozzle's discharge hole, a gas is blown onto the area including at least a portion of the region within 200 mm of the discharge hole to form a filament (the gas velocity when blowing the gas may be denoted as Vq (m / min) from now on). Examples of gas supply means used to blow the gas include supplying it from one or more directions of the filament through a blower via a slit nozzle or a flow straightening unit.

[0115] By ensuring that the area to which the gas is blown includes at least a portion of the area within 200 mm from the discharge hole, preferably at least a portion of the area within 150 mm from the discharge hole, and more preferably at least a portion of the area within 100 mm from the discharge hole, unevenness in the fineness of the thermoplastic resin fibers can be suppressed, and artificial leather with a uniform touch can be obtained.

[0116] Furthermore, regarding the gas in this process, it is preferable that its temperature be between -15°C and 50°C. By setting the lower limit of the gas temperature range to preferably -15°C or higher, more preferably -10°C or higher, and even more preferably -5°C or higher, it is possible to prevent the temperature near the discharge port from dropping excessively. On the other hand, by setting the upper limit of the gas temperature range to preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower, the discharged yarn can be sufficiently cooled.

[0117] Furthermore, in this process, it is preferable that the distance between the discharge hole and the inlet be between 100 mm and 3000 mm. Here, the "inlet" is the point where the air velocity of the gas used for traction, described later, is highest between the discharge hole and the formation of the fiber web. Generally, it is the point where the cross-sectional area of ​​the passage through which the thermoplastic resin discharged from the discharge hole passes as a thread is smallest between the discharge hole and the formation of the fiber web. When forming a fiber web by the spunbond method, it is the point where the cross-sectional area of ​​the passage of the thread of the ejector used for traction is smallest.

[0118] By setting the lower limit of the distance between the discharge hole and the inlet to preferably 100 mm or more, more preferably 200 mm or more, and even more preferably 300 mm or more, the fiberization of the molten thermoplastic elastomer resin and polyester resin can be sufficiently promoted, making stable spinning easier and enabling the production of artificial leather with excellent mechanical properties. On the other hand, by setting the upper limit of the distance between the discharge hole and the inlet to preferably 3000 mm or less, more preferably 2000 mm or less, and even more preferably 1000 mm or less, the yarn made of thermoplastic elastomer resin and polyester resin discharged from multiple discharge holes can be stably guided to the inlet, enabling the production of artificial leather with a uniform texture.

[0119] Then, the fibers are pulled at a spinning speed of 3000 m / min to 7000 m / min to form thermoplastic resin fibers. For this pulling, it is preferable to use an ejector that can pull the polymer flow by flowing gas downward at high speed, and a rectangular ejector is more preferable from the viewpoint of preventing unevenness in the width direction.

[0120] Regarding the spinning speed, it is preferable to set the spinning speed (hereinafter sometimes referred to as Vs (m / min)) to 3000 m / min or more and 7000 m / min or less. As for the lower limit of the spinning speed Vs (m / min) range, by setting the spinning speed Vs (m / min) to preferably 3000 m / min or more, more preferably 3500 m / min or more, and even more preferably 4000 m / min or more, the molecular orientation of the polyester resin is sufficient, resulting in a moderately firm touch, as well as excellent mechanical properties, making it less prone to wrinkles and stretching, and allowing for the production of an artificial leather that is less likely to lose its shape when molded. On the other hand, as for the upper limit of the spinning speed Vs (m / min) range, by setting the spinning speed Vs (m / min) to preferably 7000 m / min or less, more preferably 6500 m / min or less, and even more preferably 6000 m / min or less, the yarn to which the gas has been blown can be pulled more stably, and an artificial leather with a uniform texture can be obtained.

[0121] In this invention, the spinning speed Vs (m / min) refers to a value measured and calculated by the following method: (i) A thermoplastic resin fiber is collected from the yarn being pulled, and the fiber cross-section is photographed at a magnification of 3000x using a scanning electron microscope (for example, a "VHX-D510" manufactured by Keyence Corporation). (ii) Ten fiber cross-sections are randomly selected from the thermoplastic resin fibers, the cross-sectional area of ​​each thermoplastic resin fiber is measured, and the average cross-sectional area S (μm²) of the thermoplastic resin fibers is calculated from the arithmetic mean. ２ (iii) Calculate the amount of thermoplastic resin A discharged per thermoplastic resin fiber W from the discharge amounts of thermoplastic resin A and thermoplastic resin B during spinning. Ａ (g / min) and the amount of thermoplastic resin B discharged per thermoplastic resin fiber W Ｂ Calculate the density (g / min). Also, the density ρ of thermoplastic resin A at 20°C. Ａ (g / cm３ ) and the density ρ of thermoplastic resin B at 20°C Ｂ (g / cm ３ ) From this, the single fiber fineness F (dtex) of the thermoplastic resin fiber is calculated based on the following formula: F = S × (W Ａ +W Ｂ ) ÷ { (W Ａ / ρ Ａ ) + (W Ｂ / ρ Ｂ )} ÷ 100 ... (formula) (iv) Calculate the spinning speed Vs (m / min) based on the following formula and round it to the first decimal place Vs = (W Ａ +W Ｂ )÷F×10000 (formula).

[0122] Furthermore, when using an ejector or the like to pull the aforementioned yarn, by setting the lower limit of the temperature range of the gas used for pulling to preferably -15°C or higher, more preferably -10°C or higher, and even more preferably -5°C or higher, the yarn can be cooled uniformly, resulting in artificial leather with less fineness variation in the thermoplastic resin fibers and a uniform touch. On the other hand, by setting the upper limit of the temperature range of the gas to preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower, the yarn can be sufficiently cooled, resulting in artificial leather with less fineness variation in the thermoplastic resin fibers and a uniform touch.

[0123] Furthermore, in this process, the ratio Vq / Vs (unitless) of the gas flow velocity Vq (m / min) and the spinning speed Vs (m / min) when blowing the aforementioned gas is 3 × 10 －３ 30 x 10 －３ The following is preferable: For the lower limit of the Vq / Vs range, the above ratio is preferably 3 × 10 －３ More preferably 4 × 10 －３ More preferably 5 x 10 －３ By doing so, the aforementioned yarn can be sufficiently cooled, resulting in artificial leather with less fineness variation in the thermoplastic resin fibers and a uniform touch. On the other hand, the upper limit of the Vq / Vs range is preferably 30 × 10 －３More preferably 20 x 10 －３ More preferably 10 x 10 －３ By doing the following, the threads can be pulled more stably, and artificial leather with a uniform texture can be obtained.

[0124] <Step to form a fiber web> In this step, the thermoplastic resin fibers are collected to form a fiber web.

[0125] For this collection, it is preferable to use a moving net conveyor. By using a net conveyor, the fibers that accumulate on the upper surface of the conveyor can be sucked to the lower surface and fixed in place, suppressing curling of the fiber web during transport and resulting in artificial leather with a more uniform texture.

[0126] The net portion of this net conveyor can be made of various materials, including metal nets such as stainless steel, iron, and nickel, as well as resin nets made of polyester or fluororesin, and rubber nets.

[0127] <Process for forming a crimped fiber web> In this process, the fiber web is heat-treated at 70°C to 250°C to form a crimped fiber web using the thermoplastic resin fibers as crimped fibers.

[0128] For this heat treatment, for example, heat rolls such as hot air circulation dryers, hot air through-flow dryers, suction drum dryers, flat calender rolls, and embossing rolls can be used, as well as equipment such as continuous dyeing machines, liquid flow dyeing machines, Wins dyeing machines, and Jigger dyeing machines. In particular, it is preferable to use hot air circulation dryers, hot air through-flow dryers, and suction drum dryers because applying heat to thermoplastic resin fibers with less frictional resistance can result in crimped fibers with a greater curvature.

[0129] Furthermore, it is preferable to set the heat treatment temperature between 70°C and 250°C. The heat treatment temperature referred to here means, for example, the temperature of the gas when heat treatment is performed using a heated gas, such as in a hot air circulation dryer; the surface temperature of the roll when heat treatment is performed using a heated roll, such as a flat calender roll; and the temperature of the liquid when heat treatment is performed using a heated liquid, such as in a continuous dyeing machine. Regarding the lower limit of this heat treatment temperature, by setting the temperature to preferably 70°C or higher, more preferably 100°C or higher, and even more preferably 130°C or higher, the curvature of the thermoplastic resin fibers increases, and an artificial leather with superior flexibility can be obtained. Regarding the upper limit of the heat treatment temperature, by setting the temperature to preferably 250°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower, thermal decomposition of the thermoplastic elastomer can be prevented, and an artificial leather with a moderate rebound when gripped can be obtained.

[0130] <Process for forming a sheet base> The process may also include a step to form a sheet base by laminating multiple crimped fiber webs to a desired weight, and then intertwining the fibers using a needle punching method or a water jet punching method. By obtaining a sheet base in this way, artificial leather with good abrasion resistance can be obtained.

[0131] Furthermore, regarding the crimped fiber web (including those made of multiple layers), the melting point T of the thermoplastic resin A is determined. ｍ、Ａ (°C), melting point T of thermoplastic resin B ｍ、Ｂ Dry heat treatment can also be performed at a temperature above the lower of the two temperatures (°C) and below the other temperature. In this way, at least a portion of the thermoplastic resin fibers are fused at the lower melting point of thermoplastic resin A or thermoplastic resin B, thereby obtaining artificial leather that has both appropriate resilience and flexibility when gripped.

[0132] This dry heat treatment may involve, for example, pressing the fiber web in multiple stages using multiple flat rolls at different temperatures, or adjusting the melting point T of the thermoplastic resin A before or after pressing with the flat rolls. ｍ、Ａ (°C), melting point T of thermoplastic resin Bｍ、Ｂ Methods such as blowing a gas at a temperature above the lower of the two temperatures (°C) and below the other temperature can be used.

[0133] <Step to form a polyurethane-coated sheet> Furthermore, the method for manufacturing artificial leather according to this embodiment may include a step of applying polyurethane to the crimped fiber web or the sheet substrate to form a polyurethane-coated sheet.

[0134] In this process, depending on the desired properties, either a method of dissolving polyurethane or its precursor in a solvent such as N,N'-dimethylformamide or dimethyl sulfoxide (solvent method), or a method of using a water-dispersible polyurethane liquid obtained by dispersing a mixture containing at least a polymer diol, an organic diisocyanate, and a chain extender as an emulsion in water (water dispersion method) is preferably used. In the former solvent method, for example, the polyurethane precursor can be substantially solidified by immersing the heat-treated sheet substrate in the polyurethane solution and then drying it, or by immersing the heat-treated sheet substrate in the polyurethane solution and then solidifying it by immersing it in another solvent in which the polyurethane is insoluble. On the other hand, in the latter water dispersion method, for example, the heat-treated sheet substrate can be solidified by immersing it in the water-dispersible polyurethane liquid and then drying it, or by a dry solidification method.

[0135] <Polishing or Water-Entanglement Process> In this process, at least one surface of the crimped fiber web is polished or entangled with water. In this process, the sheet substrate and the polyurethane-coated sheet are treated as the crimped fiber web. Furthermore, the sheet that has undergone this process may be referred to as a standing-pile sheet.

[0136] First, for polishing, it is preferable to polish at least one surface of the crimped fiber web obtained by the above method using sandpaper or a roll sander. In particular, by using sandpaper, regions α and β of the thermoplastic resin fibers can be uniformly peeled off. In particular, in order to uniformly peel regions α and β of the thermoplastic resin fibers, it is preferable to reduce the grinding load in the polishing process. As a specific means for reducing the grinding load, for example, it is more preferable to use multi-stage buffing with three or more buffing stages, and to set the grit of the sandpaper used in each stage to the range of 120 (P120) to 600 (P600) as specified in JIS R6010:2000 "Grit size of abrasives for abrasive cloths and papers".

[0137] Furthermore, in order to separate region α and region β of the thermoplastic resin fiber, it is also preferable to perform a step of entangling with water on at least one surface of the crimped fiber web obtained by the above method.

[0138] <Step of providing a resin layer> The crimped fiber web, the sheet substrate, the polyurethane-coated sheet, the pile sheet, or any of these sheets that have undergone other finishing steps described later (hereinafter referred to as "sheet-like material") may further include a step of providing a resin layer on at least one of its surfaces. Hereafter, a sheet that has undergone this step may be referred to as a resin-coated sheet.

[0139] In this process, methods for forming the resin layer include, for example, coating embossed release paper with a pigment-colored one-component polyurethane resin and drying it in an oven, then coating it with a two-component polyurethane resin as an adhesive and drying it again in an oven, bonding the resulting resin layer to the sheet-like material, and peeling off the release paper after the reaction is complete; or directly coating the surface of the sheet-like material with polyurethane dissolved in a solvent such as N,N'-dimethylformamide or dimethyl sulfoxide, immersing it in another solvent in which the polyurethane is insoluble to solidify, then washing and drying it, and finally bonding it to the resin layer formed on the release paper mentioned above.

[0140] Furthermore, discrete resin layers can also be provided. Methods for this include applying a polymeric elastic material such as polyurethane to the surface of a sheet-like material in a desired pattern and curing it, as in the case of providing the resin layers described above, and forming the resin layers on a support substrate such as release paper, then applying an adhesive to the surface of the resin layers and bonding them to the surface of the sheet-like material. Methods for providing discrete resin layers include applying a polymeric elastic material such as polyurethane to the surface of a sheet-like material in a desired pattern and curing it, as in the case of providing the resin layers described above, and forming the sheet-like material on a support substrate such as release paper, then applying an adhesive to the surface of the resin layers and bonding them to the surface of the sheet-like material.

[0141] Furthermore, the process of applying this resin layer can be carried out during or after the other finishing processes described later. For example, the resin layer application process may be performed after the dyeing process described later, and this can be used to make artificial leather, or the resin layer application process may be performed after the dyeing process described later, and then holes may be punched to make this artificial leather.

[0142] <Other Finishing Processes> In the method for manufacturing artificial leather according to this embodiment, it is preferable to perform various further finishing processes on the pile sheet or the resin-coated sheet, similar to general artificial leather. Of course, in the present invention, the artificial leather obtained by performing these finishing processes is also considered to be the artificial leather of the present invention.

[0143] First, in this finishing process, functional agents such as dyes, pigments, softeners, anti-pilling agents, antibacterial agents, deodorizers, water repellents, lightfasteners, and weather-resistant agents can be impregnated into or applied to the aforementioned pile sheet and resin-coated sheet.

[0144] Furthermore, the aforementioned pile sheets and resin-coated sheets can also be dyed. While there are no particular limitations on the specific means of this dyeing process, a liquid flow dyeing machine is preferably used because a more flexible artificial leather can be obtained by adding a kneading effect at the same time as dyeing. The temperature of the dyeing solution when dyeing is preferably between 100°C and 150°C. Disperse dyes are preferably used as the dye. Reductive washing can also be performed after dyeing. Furthermore, it is preferable to use dyeing aids when dyeing in order to improve the uniformity of the dyeing. In this dyeing process, finishing treatments such as softeners such as silicone, antistatic agents, water repellents, flame retardants, and lightfasteners can also be applied. These finishing treatments can be performed after dyeing or in the same bath as the dyeing.

[0145] Alternatively, various post-processing steps such as perforation, embossing, stitching, foil stamping, resin printing, inkjet printing, laser etching, and lamination of knitted or woven fabrics, films, or polyurethane foam to the back of the substrate to improve strength and integral molding properties can also be performed.

[0146] [Applications of Artificial Leather (Vehicle Interior Materials, Vehicle Parts, Seats, Vehicles, Clothing)] The artificial leather of the present invention has an elegant and luxurious appearance, high strength, and excellent flexibility, making it suitable for a wide range of applications, including clothing, general merchandise, shoes and bags, vehicle interior materials, seats, CD curtains, DVD curtains, base materials for polishing pads, various polishing cloths, and other industrial materials.

[0147] Among these, vehicle interior materials including the aforementioned artificial leather are preferred because they can take advantage of their excellent flexibility and abrasion resistance. Such vehicle interior materials are preferably used in vehicle parts such as the steering wheel, horn switch, shift knob, dashboard, instrument panel, glove box, floor carpet, floor mats, headliner, sun visor, and assist grips of an automobile. In other words, it is preferable that these vehicle parts include the aforementioned artificial leather. In this invention, "vehicle" includes automobiles, aircraft, railway vehicles, ships, as well as carriages, palanquins, rickshaws, and even some industrial, construction, and agricultural machinery that can transport people or animals, such as excavators, cranes, tractors, and combine harvesters. Furthermore, the vehicle interior material including the aforementioned artificial leather may be artificial leather itself, or it may be a laminate of artificial leather with other sheet materials such as foamed resin sheets, woven or knitted fabrics, or films.

[0148] Alternatively, seats containing the aforementioned artificial leather are also preferable because they can take advantage of its particularly excellent flexibility and abrasion resistance. In such seats, it is even more preferable that at least a part of the surface material, such as the headrest, seat surface, armrests, and footrests, for example, the part that comes into direct contact with the occupant, is made of the aforementioned artificial leather. Of course, the seats of the present invention can be used not only for vehicles such as automobiles, aircraft, railway cars, and ships, but also for seats in homes, offices, and shops. In this invention, "seat" includes chairs, benches, sofas, couches, stools, and floor chairs.

[0149] Therefore, a vehicle comprising at least one of the vehicle interior material, the vehicle component, and the seat is preferable because it can take advantage of the excellent properties of the artificial leather, particularly its flexibility and abrasion resistance.

[0150] Furthermore, clothing containing the aforementioned artificial leather is also preferable because it can take advantage of its particularly excellent flexibility and abrasion resistance. Examples of such clothing include trousers, skirts, dresses, sweaters, cardigans, jackets, and coats, and it is preferable that at least a part of them, such as the front, back, sleeves, collar, and pockets, contains the aforementioned artificial leather. Of course, these front parts may also be made of the aforementioned artificial leather itself.

[0151] Next, the present invention will be specifically described based on examples. However, the present invention is not limited to these examples.

[0152] [Measurement Method] Each characteristic value in the examples was measured and calculated using the following method. Unless otherwise specified, the measurement and calculation methods for each physical property were performed based on the methods described above.

[0153] (1) Polyurethane resin content The percentage of polyurethane resin content (mass%) in the artificial leather was measured and calculated using the method described above, with N,N'-dimethylformamide used as the solvent for eluting the polyurethane resin.

[0154] (2) Average equivalent diameter of thermoplastic resin fibers φ ＰＳ１ , φ ＰＣ , φ ＰＳ２ Furthermore, the curvature r of the thermoplastic resin fiber ＰＳ１ ,r ＰＣ ,r ＰＳ２ Average equivalent diameter of thermoplastic resin fibers φ ＰＳ１ , φ ＰＣ , φ ＰＳ２ (μm), and the curvature r of the thermoplastic resin fiber. ＰＳ１ ,r ＰＣ ,r ＰＳ２ The (unitless) values ​​were measured and calculated using the method described above, with a scanning electron microscope, the "VHX-D510" manufactured by Keyence Corporation.

[0155] (3) Part P Ｃ The average elastic modulus portion P of regions α and β at 25°C, as measured by atomic force microscopy of thermoplastic resin fibers. ＣThe average elastic moduli of regions α and β at 25°C, measured by atomic force microscopy of thermoplastic resin fibers, were measured and calculated using the method described above, with a Leica "Ultracut-UCT" cryomicrotome, a Bruker Japan "NanoScope V Dimension Icon" probe microscope, and a Bruker Japan "RTESPA-150" RTESPA-type silicon probe.

[0156] (4) Part P Ｃ The number of connections between regions α and β in this region N Ｃ Part P Ｃ The number of connections between regions α and β in this region N Ｃ The (unitless) value was measured and calculated using the aforementioned scanning electron microscope "VHX-D510" and the method described above.

[0157] (5) Weight and thickness of artificial leather Weight of artificial leather (g / m ２ The mass was measured and calculated using the method described in "Method B (ISO method)" of "8.3.2 Mass per unit area under standard conditions" in JIS L1096:2020 "Test methods for woven and knitted fabrics". The thickness (μm) of the artificial leather was measured and calculated using a dial thickness gauge (manufactured by Ozaki Seisakusho Co., Ltd., product name "Peacock (registered trademark) H").

[0158] (6) Area ratio of pigment in thermoplastic resin fibers to the cross-section of thermoplastic resin fibers The area ratio (%) of pigment in thermoplastic resin fibers to the cross-section of thermoplastic resin fibers was measured and calculated using the method described above, with a scanning electron microscope (SEM) "VHX-D510" manufactured by Keyence Corporation and image analysis software "ImageJ".

[0159] (7) Pile length and number of surface fiber ends The pile length (μm) and the number of surface fiber ends (number of fibers) were measured and calculated using the method described above with a scanning electron microscope, the "VHX-D510" manufactured by Keyence Corporation.

[0160] (8) Determination of the thickness of the resin layer Whether or not a surface is provided with a resin layer, and the thickness of the resin layer (μm), were evaluated using the method described above with a scanning electron microscope, the "VHX-D510" manufactured by Keyence Corporation.

[0161] (9) Breaking strength per unit weight As an indicator of the moldability of artificial leather, the breaking strength (N / (g / m)) standardized per unit weight ２ The following was determined: Specifically, the breaking strength was measured according to JIS L1096:2020 "Testing Methods for Woven and Knitted Fabrics" "8.14.1 Tensile Strength and Elongation" (Method A: Strip Method), with a test specimen width of 25 mm, a gripping distance of 100 mm, and a tensile speed of 100 mm / min, and the breaking strength (N) was calculated as the basis weight (g / m) of the artificial leather. ２ The value obtained by dividing by ) was rounded to the third decimal place.

[0162] (10) Bending rigidity: For the bending rigidity of the artificial leather, a pure bending test machine, "KES-FB2-A" manufactured by Kato Tech Co., Ltd., was used. Three artificial leather samples cut to 10 cm x 10 cm were taken, with a sensitivity of SENS = 20 and a speed of 0.50 cm. －１ / sec, measurement curvature 0.5cm －１ ~2.5cm －１ Bending tests were performed in the MD direction (vertical direction) and CD direction (horizontal direction) to determine the bending stiffness (g・cm²). ２ The bending stiffness ( / cm) was calculated by taking the average of the values ​​in the MD and CD directions and rounding to the third decimal place.

[0163] (11) Evaluation of texture A 20cm x 20cm test piece was randomly cut from the artificial leather, and the surface with the pile and resin layer of the test piece was placed facing upwards. The appearance when bent with the center facing inwards and the appearance when grasped were judged according to the following criteria. A: When bent it bent in a rounded manner, and no grain or wrinkles were generated. It also had excellent drape. B: When bent it bent in a rounded manner, but dense and fine creases were generated. It had excellent drape. C: When bent it bent and folded, and dense and fine creases were generated. It had slightly poor drape. D: When bent it bent and folded, and coarse grain and deep wrinkles were generated. It also had poor drape. E: It had a texture with a remarkably low sense of fullness.

[0164] (12) Evaluation of Surface Touch For the evaluation of the surface touch of artificial leather, for artificial leather without a resin layer on the surface, artificial leather samples cut to 10 cm x 10 cm were placed with the surface with the raised nap facing upwards, and 20 people skilled in evaluating artificial leather acted as evaluators. The degree of surface touch when the surface was stroked with a finger was evaluated according to the following five criteria, and the average score was rounded to two decimal places to obtain the evaluation score. ・5 points: Moist and pleasant touch ・4 points: Smooth touch (intermediate between 3 and 5 points) ・3 points: Dry touch ・2 points: Slightly rough touch (intermediate between 1 and 3 points) ・1 point: Feels rough.

[0165] (13) Color development (brightness L) ＊ (Value) Using a spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd.: "NF555"), dyed artificial leather was cut out in accordance with JIS Z8729, and the surface L ＊ a ＊ b ＊ Lightness L from the color system coordinate values ＊ The value was calculated. L ＊ The value was determined from the average of three points measured by randomly selecting them from the test specimen.

[0166] (14) Lightfastness: The degree of discoloration of the sample after irradiation with xenon arc light is graded using the gray scale for discoloration specified in JIS L0804:2004 "Gray Scale for Discoloration", and grade 4 or higher (L ＊ a ＊ b ＊ Color difference ΔE due to color system ＊ ａｂ A score of 1.7 ± 0.3 or less was considered acceptable.

[0167] [Thermoplastic Resins] The following thermoplastic resins were used in the examples and comparative examples. Hereafter, including in the table, they may be abbreviated as shown at the beginning. PET1: Polyethylene terephthalate (homopolymer, melting point: 260°C, modulus of elasticity at 25°C measured by atomic force microscope: 2030 MPa, intrinsic viscosity (IV): 0.65) PET2: PET1 with carbon black added to achieve a pigment content of 5.0% by mass PBT: Polybutylene terephthalate (homopolymer, melting point: 223°C, modulus of elasticity at 25°C measured by atomic force microscope: 1925 MPa, intrinsic viscosity (IV): 0.70) TPE1: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 5557M (manufactured by Toray Celanese Co., Ltd., melting point: 209°C, modulus of elasticity at 25°C measured by atomic force microscope: 216 MPa) TPE2: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 6347M (manufactured by Toray Celanese Co., Ltd., melting point: 213°C, modulus of elasticity at 25°C measured by atomic force microscope: 339 MPa) [Example 1] (Steps to form thermoplastic resin fibers) TPE1 is used as the thermoplastic resin A that forms region α in section P Ａ The sum of the discharge volumes for each individual section (this is the total discharge volume for all sections, (section P Ａ (Single-section discharge volume) × (Section P Ａ It can be calculated by the number of sections. 0.36 g / min of PET1 is used as the thermoplastic resin B that forms region β, and section P Ｂ The sum of the discharge volumes for each individual section (this is the total discharge volume for all sections, (section P Ｂ (Single-section discharge volume) × (Section P ＢThe number of sections can be calculated. The amount was set to 1.20 g / min and combined in a hollow annular petal-shaped 24-section / split-fiber type nozzle, and discharged from the discharge hole of the nozzle. This discharge hole is exemplified in Figure 10 (Nozzle discharge surface), and is located in section P Ａ and section P Ｂ A configuration in which these elements were arranged alternately was used. At this time, the ratio of the total single-section discharge volume of thermoplastic resin A to the total single-section discharge volume of thermoplastic resin B (hereinafter, including in the table, this may be abbreviated as "discharge volume ratio") was 23:77.

[0168] Subsequently, in the region from 30 mm to 500 mm from the discharge port, 15°C air was blown as a cooling airflow at a flow rate of Vq = 30.0 (m / min) while forming a yarn. Then, at a spinning speed Vs = 4600 m / min, the yarn was pulled with 15°C air to form thermoplastic resin fibers. The distance between the discharge port and the inlet was 700 mm.

[0169] (Process for forming a fiber web) The thermoplastic resin fibers were then collected on a moving net conveyor under suction to form a fiber web.

[0170] (Process for forming a crimped fiber web) The obtained fiber web was heat-treated in a hot air circulating dryer at 150°C for 5 minutes to form a crimped fiber web.

[0171] (Process for forming the sheet substrate) Three crimped fiber webs are laminated to form a sheet of 286 g / m². ２ After that, a heat press treatment (dry heat press) was performed. In this process, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, and the apparent density of the resulting nonwoven fabric was 0.25 g / cm³. ３ A clearance was created so that the sheet base, which is a nonwoven fabric, was formed by applying a heat press for 10 seconds.

[0172] (Process for forming polyurethane-coated sheets) First, a water-dispersible polyurethane liquid containing polyetherdiol and organic diisocyanate was prepared. The sheet substrate obtained above was immersed in this water-dispersible polyurethane liquid, and then dried with hot air at 120°C to form a polyurethane-coated sheet with a polyurethane resin content of 33% by mass (abbreviated as PU in Tables 1-6).

[0173] (Polishing or water flow entanglement process) One surface of the obtained polyurethane-coated sheet was polished with 320-grit sandpaper to form a piled portion on its surface, thereby forming a piled sheet.

[0174] (Other finishing processes) Artificial leather was obtained by dyeing the obtained pile sheet with a dyeing solution prepared so that the amount of disperse dye (Dianix Black CC-R, manufactured by Dystar Japan Co., Ltd.) was 15 parts by mass per 100 parts by mass of pile sheet, using a liquid flow dyeing machine with the dyeing solution temperature set to 130°C. The results are shown in Table 1.

[0175] [Example 2] (Step of forming thermoplastic resin fibers) Section P Ａ Set the total discharge volume of each single section to 0.10 g / min, section P Ｂ Artificial leather was obtained in the same manner as in Example 1, except that the total discharge volume of the single compartments was changed to 0.10 g / min, and the mixture was combined within a side-by-side nozzle. The results are shown in Table 1.

[0176] [Example 3] Artificial leather was obtained in the same manner as in Example 1, except that thermoplastic resin A was replaced with PBT in the process of forming thermoplastic resin fibers. The results are shown in Table 1.

[0177] [Example 4] Artificial leather was obtained in the same manner as in Example 1, except that the polishing or water flow entanglement process was changed to grinding with 120-grit sandpaper. The results are shown in Table 1.

[0178] [Example 5] (Step of forming thermoplastic resin fibers) Section P Ａ The total discharge volume of each single section is set to 0.18 g / min, section P ＢArtificial leather was obtained in the same manner as in Example 4, except that the total discharge volume of the single section was changed to 0.80 g / min. The results are shown in Table 1.

[0179]

[0180] [Example 6] (Step of forming thermoplastic resin fibers) Section P Ａ Artificial leather was obtained in the same manner as in Example 1, except that the total discharge volume of the single section was changed to 0.60 g / min. The results are shown in Table 2.

[0181] [Example 7] (Steps to form thermoplastic resin fibers), (Steps to form a fiber web) A fiber web was formed in the same manner as in Example 1.

[0182] (Process for forming crimped fiber webs) In addition to the crimped fiber webs obtained by heat treatment at 150°C for 5 minutes in a hot air circulating dryer in the same manner as in Example 1, crimped fiber webs obtained by heat treatment at 100°C were also prepared.

[0183] (Process for forming the sheet substrate) Three layers of crimped fiber web obtained by heat treatment at 150°C, crimped fiber web obtained by heat treatment at 100°C, and crimped fiber web obtained by heat treatment at 100°C are laminated in that order to form a sheet weighing 286 g / m². ２ After that, a heat press treatment (dry heat press) was performed. In this process, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, and the apparent density of the resulting nonwoven fabric was 0.25 g / cm³. ３ A clearance was created so that the sheet base, which is a nonwoven fabric, was formed by applying a heat press for 10 seconds.

[0184] (Process for forming the polyurethane-coated sheet) A polyurethane-coated sheet was formed in the same manner as in Example 1.

[0185] (Polishing or water flow entanglement process) The surface of the crimped fiber web side obtained by heat treatment of the polyurethane-coated sheet at 150°C was polished with 320-grit sandpaper to form a piled portion on the surface, thereby forming a piled sheet.

[0186] (Other finishing processes) The obtained pile sheet was dyed using disperse dyes in a jet dyeing machine at 130°C to obtain artificial leather. The results are shown in Table 2.

[0187] [Example 8] Artificial leather was obtained in the same manner as in Example 7, except that in the (step of forming a sheet substrate), three layers were stacked in the order of crimped fiber web obtained by heat treatment at 100°C, crimped fiber web obtained by heat treatment at 150°C, and crimped fiber web obtained by heat treatment at 150°C, and furthermore, in the (step of polishing or water flow entanglement), the surface of the crimped fiber web obtained by heat treatment at 100°C was polished. The results are shown in Table 2.

[0188] [Example 9] (Steps to form thermoplastic resin fibers), (Steps to form a fiber web) A fiber web was formed in the same manner as in Example 1.

[0189] (Process for forming crimped fiber webs) In addition to the crimped fiber webs obtained by heat treatment at 150°C for 5 minutes in a hot air circulating dryer in the same manner as in Example 1, crimped fiber webs obtained by heat treatment at 180°C were also prepared.

[0190] (Process for forming the sheet substrate) Three layers of crimped fiber web obtained by heat treatment at 150°C, crimped fiber web obtained by heat treatment at 180°C, and crimped fiber web obtained by heat treatment at 180°C are laminated in that order to form a sheet weighing 286 g / m². ２ After that, a heat press treatment (dry heat press) was performed. In this process, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, and the apparent density of the resulting nonwoven fabric was 0.25 g / cm³. ３ A clearance was created so that the sheet base, which is a nonwoven fabric, was formed by applying a heat press for 10 seconds.

[0191] (Process for forming the polyurethane-coated sheet) A polyurethane-coated sheet was formed in the same manner as in Example 1.

[0192] (Polishing or water flow entanglement process) The surface of the crimped fiber web side obtained by heat treatment of the polyurethane-coated sheet at 150°C was polished with 320-grit sandpaper to form a piled portion on the surface, thereby forming a piled sheet.

[0193] (Other finishing processes) The obtained pile sheet was dyed using disperse dyes in a jet dyeing machine at 130°C to obtain artificial leather. The results are shown in Table 2.

[0194] [Example 10] Artificial leather was obtained in the same manner as in Example 9, except that in the (step of forming a sheet substrate), three layers were stacked in the order of crimped fiber web obtained by heat treatment at 180°C, crimped fiber web obtained by heat treatment at 150°C, and crimped fiber web obtained by heat treatment at 150°C, and furthermore, in the (step of polishing or water flow entanglement), the surface of the crimped fiber web obtained by heat treatment at 180°C was polished. The results are shown in Table 2.

[0195]

[0196] [Comparative Example 1] Artificial leather was obtained in the same manner as in Example 1, except that the steps for forming thermoplastic resin fibers and forming a fiber web were replaced with the following. The results are shown in Table 3.

[0197] (Process for forming thermoplastic resin fibers) As the thermoplastic resin A that forms region α, TPE1 is used in section P Ａ The total discharge volume of each section is 0.36 g / min, and PET is used as the thermoplastic resin B resin that forms region β in section P. Ｂ The total discharge volume of each individual section was 1.20 g / min, and the mixture was combined in a hollow, annular, petal-shaped nozzle with 24 divisions and split fibers, and then discharged from the discharge hole. At this time, the discharge volume ratio was 23:77.

[0198] Subsequently, while blowing 15°C air as a cooling airflow at a flow rate of Vq = 30.0 (m / min) in the region from 30 mm to 500 mm from the discharge hole, a yarn was formed. After rolling the yarn at a spinning speed Vs = 1600 (m / min), a thermoplastic resin fiber with an average circle equivalent diameter of 18.5 μm was formed under conditions of a draw ratio of 2.9 times.

[0199] (Process for forming the fiber web) The obtained thermoplastic resin fibers were cut to a length of 5 mm, dispersed in water, and a fiber web was obtained by papermaking.

[0200] [Comparative Example 2] (Step of forming thermoplastic resin fibers) Section P Ａ The total discharge volume of each single section is set to 0.03 g / min, section P Ｂ Artificial leather was obtained in the same manner as in Example 1, except that the total discharge volume of the single section was changed to 0.10 g / min, the flow was changed to merge within a side-by-side nozzle, and the grinding (polishing or water flow entanglement process) was changed to use 120-grit sandpaper. The results are shown in Table 3.

[0201] [Comparative Example 3] (Step of forming thermoplastic resin fibers) Section P Ａ Artificial leather was obtained in the same manner as in Example 1, except that the total discharge volume of each section was set to 1.20 g / min. The results are shown in Table 3.

[0202] [Comparative Example 4] (Steps to form thermoplastic resin fibers), (Steps to form fiber webs) Fiber webs were formed in the same manner as in Example 1.

[0203] (Process for forming crimped fiber webs) In addition to webs formed in the same manner as in Example 1, webs were prepared in which the (process for forming crimped fiber webs) was not performed (webs that remained as fiber webs, hereafter referred to as fiber webs).

[0204] (Process for forming the sheet substrate) The crimped fiber web, fiber web, and fiber web obtained are stacked in that order to form a sheet of 286 g / m². ２ After that, a heat press treatment (dry heat press) was performed. In this process, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, and the apparent density of the resulting nonwoven fabric was 0.25 g / cm³. ３ A clearance was created so that the sheet base, which is a nonwoven fabric, was formed by applying a heat press for 10 seconds.

[0205] (Process for forming the polyurethane-coated sheet) A polyurethane-coated sheet was formed in the same manner as in Example 1.

[0206] (Polishing or water flow entanglement process) The surface of the crimped fiber web side of the obtained polyurethane-coated sheet was polished with 320-grit sandpaper to form a piled portion on the surface, thereby forming a piled sheet.

[0207] (Other finishing processes) The obtained pile sheet was dyed using disperse dyes in a jet dyeing machine at 130°C to obtain artificial leather. The results are shown in Table 3.

[0208] [Comparative Example 5] Artificial leather was obtained in the same manner as in Comparative Example 4, except that in the (process of forming a sheet substrate), three layers were stacked in the order of the obtained crimped fiber web, the obtained crimped fiber web, and the fiber web, and in the (process of polishing or water flow entanglement), the surface of the fiber web side was polished. The results are shown in Table 3.

[0209]

[0210] [Comparative Example 6] (Steps to form thermoplastic resin fibers), (Steps to form fiber webs) Fiber webs were formed in the same manner as in Example 1 (referred to as fiber web 1). Furthermore, fiber webs were formed in the same manner as in Example 1, except that TPE2 was used as the thermoplastic resin A forming region α, and 5°C air was blown as cooling air (referred to as fiber web 2).

[0211] (Process for forming crimped fiber webs) Fiber web 1 was heat-treated in a hot air circulating dryer at 150°C for 5 minutes to form a crimped fiber web (referred to as crimped fiber web 1). Furthermore, fiber web 2 was heat-treated in a hot air circulating dryer at 180°C for 5 minutes to form a crimped fiber web (referred to as crimped fiber web 2).

[0212] (Process for forming the sheet substrate) Three layers of crimped fiber web 1, crimped fiber web 2, and crimped fiber web 2 are laminated in that order to form a sheet of 286 g / m². ２ After that, a heat press treatment (dry heat press) was performed. In this process, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, and the apparent density of the resulting nonwoven fabric was 0.25 g / cm³. ３A clearance was created so that the sheet base, which is a nonwoven fabric, was formed by applying a heat press for 10 seconds.

[0213] (Process for forming the polyurethane-coated sheet) A polyurethane-coated sheet was formed in the same manner as in Example 1.

[0214] (Polishing or water flow entanglement process) The surface of the crimped fiber web 1 side of the obtained polyurethane-coated sheet was polished with 320-grit sandpaper to form a piled portion on its surface, thereby forming a piled sheet.

[0215] (Other finishing processes) The obtained pile sheet was dyed using disperse dyes in a jet dyeing machine at 130°C to obtain artificial leather. The results are shown in Table 4.

[0216] [Comparative Example 7] Artificial leather was obtained in the same manner as in Example 7, except that in the (step of forming a sheet substrate), three sheets of crimped fiber web 2, crimped fiber web 1, and crimped fiber web 1 were laminated in that order, and in the (step of polishing or water flow entanglement), the surface on the crimped fiber web 2 side was polished. The results are shown in Table 4.

[0217]

[0218] [Example 11] (Process for forming thermoplastic resin fibers) to (Other finishing processes) A ​​pile sheet was formed in the same manner as in Example 1, and this pile sheet was dyed at 130°C using a disperse dye in a jet dyeing machine.

[0219] (Process for forming the resin layer) A water-dispersible polyurethane liquid containing polycarbonate diol as a polymer diol, aromatic diisocyanate as an organic diisocyanate, and ethylene glycol as a chain extender was mixed with a carbon black-based black pigment in a mixer to prepare a resin liquid for forming the resin layer. This resin liquid was applied in a sheet form to release paper having a textured surface using a comma coater and treated in a dryer at 100°C for 3 minutes to form a non-porous resin layer with a thickness of 70 μm. Next, a polycarbonate-based polyurethane resin was applied to the surface of the resin film as an adhesive using a comma coater and heated in a dryer at 100°C for 1 minute. Then, the resin layer was placed on the surface of the piled sheet with the piled portion formed thereon, and with the resin layer facing upwards, it was dry-heat pressed for 1 minute under the conditions of an upper plate temperature of 110°C, a lower plate temperature of 25°C, and a press pressure of 20.0 kPa to bond it. The release paper was then peeled off to obtain artificial leather with a resin layer formed on the surface. The results are shown in Table 5.

[0220] [Comparative Example 8] (Process for forming thermoplastic resin fibers) to (Other finishing processes) A ​​pile sheet was formed in the same manner as in Comparative Example 4, and this pile sheet was dyed at 130°C using a disperse dye in a jet dyeing machine.

[0221] (Step of forming a resin layer) Artificial leather was obtained by forming a resin layer on the surface in the same manner as in Example 11. The results are shown in Table 3.

[0222]

[0223] [Example 12] Artificial leather was obtained in the same manner as in Example 1, except that in the step of forming thermoplastic resin fibers, thermoplastic resin B was changed to PET2, and in the other finishing steps, the material was treated with a liquid flow dyeing machine without using dyes. The results are shown in Table 6.

[0224] [Example 13] Artificial leather was obtained in the same manner as in Example 12, except that in the step of forming a polyurethane-coated sheet, the water-dispersible polyurethane solution was formulated so that the carbon black content relative to the solid content of the water-dispersible polyurethane was 3.0% by mass. Note that the carbon black content relative to the solid content of the water-dispersible polyurethane and the carbon black content in the polyurethane resin of the artificial leather did not change. The results are shown in Table 6.

[0225] [Comparative Example 9] Artificial leather was obtained in the same manner as in Comparative Example 4, except that after dyeing with a liquid flow dyeing machine in the (other finishing process), an alkaline washing treatment at 80°C was performed, followed by rinsing with water. The results are shown in Table 6.

[0226] [Comparative Example 10] Artificial leather was obtained in the same manner as in Comparative Example 1, except that in the step of forming thermoplastic resin fibers, thermoplastic resin B was changed to PET2, and in the other finishing steps, the material was treated with a liquid jet dyeing machine without using dyes. The results are shown in Table 6.

[0227] [Example 14] (Step of forming a sheet substrate) Two crimped fiber webs obtained were laminated to form a sheet with a density of 191 g / m². ２Artificial leather was obtained in the same manner as in Example 12, except for the above. The obtained artificial leather and the following woven fabric F1 were laminated and subjected to a heat press treatment (dry heat press). At this time, the surface temperature of the upper plate was set to 180°C and the surface temperature of the lower plate was set to 180°C, a clearance of 0.83 mm was provided, and a heat press was performed for 10 seconds to obtain an artificial leather / woven fabric laminate. The results are shown in Table 6. <Woven fabric F1> (Yarn 1): Polyethylene terephthalate with an intrinsic viscosity (IV) of 0.66 was spun and drawn to obtain a multifilament with a total fineness of 56 decitex and 48 filaments. This was S-twisted, twisted at 2200 T / m, and steam-set at 75°C. (Yarn 2): Polyethylene terephthalate with an intrinsic viscosity (IV) of 0.66 was spun and drawn to obtain a multifilament with a total fineness of 56 decitex and 48 filaments. This yarn was twisted using the Z-twist method at 2200 T / m and then steam-set at 75°C. (Weave structure): ・Warp: Yarn 1 and Yarn 2 are arranged alternately (indicated as "Yarn 1 / Yarn 2" in the table). ・Weft: Yarn 2 ・Weave density in the warp direction: 92 threads / 2.54 cm ・Weave density in the weft direction: 66 threads / 2.54 cm ・Weight: 60 g / m ２

[0228]

[0229] As shown in Tables 1 and 2, the artificial leathers of Examples 1 to 10 have high breaking strength per unit weight and low bending rigidity, thus possessing a high level of both strength and flexibility. On the other hand, as shown in Tables 3 and 4, the artificial leathers of Comparative Examples 1, 6, and 7 were excellent in flexibility but inferior in strength. Similarly, the artificial leathers of Comparative Examples 2 to 5 were excellent in strength but inferior in flexibility. And as shown in Table 5, the artificial leather of Example 11 has high breaking strength per unit weight and low bending rigidity, thus possessing a high level of both strength and flexibility, while the artificial leather of Comparative Example 8 was excellent in strength but inferior in flexibility.

[0230] Furthermore, as shown in Table 6, the artificial leathers of Examples 12 and 13, which contain pigments in thermoplastic resin fibers, exhibited a high level of both strength and flexibility as well as excellent lightfastness. On the other hand, the artificial leather of Comparative Example 9 showed inferior flexibility and weatherfastness. The artificial leather of Comparative Example 10 showed excellent weatherfastness but inferior strength. The artificial leather / woven / knitted laminate of Example 14 exhibited a high level of both strength and flexibility as a base material, due to its high breaking strength per unit weight and low bending rigidity.

[0231] 12, 51, 61, 71: Pile portion 13, 52, 62, 72: Base portion 14, 63, 73: Surface resin layer (silver surface portion) 15, 53: Tip of the pile portion 16: Edge of the surface resin layer 17, 54: Edge of the other surface 181, 551: Imaginary line passing through the edge of the pile portion or resin layer 182, 552: Imaginary line passing through the edge of the other surface 18A: Imaginary line A 18B: Imaginary line B 18C: Imaginary line C 18D: Imaginary line D 191: Part P Ｓ１ 192: Part P Ｃ 193: Part P Ｓ２ 21: Planar, wavy crimped fiber 31: Coiled crimped fiber 41, 92: Region α 42, 93: Region β 81: Fiber 82: Apex of the curved section 83: Baselines tangent to two curved sections opposite to the apex of the curved section 84: 100 μm long chord parallel to baseline F 101: Nozzle discharge surface 102: Nozzle discharge hole L: Distance between 52 and 54 P ｎ : Points on the boundary line between the arrowhead and the base (n=1 to 10) R ｎ : Hair length (n=1-10) S ｎ : Perpendicular line (n = 1 to 10) Q ｎ : Points at the tips of the upright hairs (n = 1 to 10)

Claims

1. An artificial leather comprising a long fiber non-woven fabric composed of thermoplastic resin fibers that are crimped fibers, having a raised hair portion having raised hairs and / or a resin layer on one surface of the artificial leather, and in a cross-section parallel to the thickness direction of the artificial leather, a virtual line A is drawn at a distance of 10% of the thickness of the artificial leather from the reference line of the surface having the raised hair portion and / or the resin layer to the reference line of the other surface, a virtual line B is drawn at a distance of 25% of the thickness of the artificial leather from the reference line of the surface having the raised hair portion and / or the resin layer to the reference line of the other surface, a virtual line C is drawn at a distance of 35% of the thickness of the artificial leather from the reference line of the surface having the raised hair portion and / or the resin layer to the reference line of the other surface, a virtual line D is drawn at a distance of 90% of the thickness of the artificial leather from the reference line of the surface having the raised hair portion and / or the resin layer to the reference line of the other surface, respectively, and a portion from the reference line of the one surface to the virtual line A is portion P Ｓ１ , a portion from the virtual line B to the virtual line C is portion P Ｃ , a portion from the virtual line D to the reference line of the other surface is portion P Ｓ２ , and when so defined, an artificial leather that satisfies the following formulas 1 to 4. 1.4×φ ＰＳ１ ≦φ ＰＣ ≦4.0×φ ＰＳ１ ... (Formula 1) 0.05≦r ＰＳ１ ≦0.20... (Formula 2) 0.05≦r ＰＳ２ ≦0.20... (Formula 3) 0.05≦r ＰＣ ≦0.20... (Formula 4) Here, φ ＰＳ１ is the average circle equivalent diameter (μm) of the thermoplastic resin fibers in the portion P Ｓ１ , φ ＰＣ is the average circle equivalent diameter (μm) of the thermoplastic resin fibers in the portion P Ｃ , r ＰＳ１ is the curvature of the thermoplastic resin fibers in the portion P Ｓ１ , r ＰＣ is the curvature of the thermoplastic resin fibers in the portion P Ｃ , r ＰＳ２ is the curvature of the thermoplastic resin fibers in the portion P Ｓ２ This is the curvature of the thermoplastic resin fiber in the given context.

2. Said φ ＰＳ１ The artificial leather according to claim 1, wherein the particle size is 2.0 μm or more and 10.0 μm or less.

3. Said part P Ｃ The artificial leather according to claim 1 or 2, wherein the thermoplastic resin fiber has a region α in which the elastic modulus at 25°C measured by an atomic force microscope is 20 MPa or more and 400 MPa or less, and a region β in which the elastic modulus at 25°C measured by an atomic force microscope is 1000 MPa or more and 5000 MPa or less, and the region α and the region β have a portion in which they are connected three or more times in the order of region α, region β, region α, region β, region α.

4. Furthermore, the artificial leather according to claim 1 or 2, satisfying the following formula 5: 1.4 × φ ＰＳ２ ≦φ ＰＣ ≤4.0 × φ ＰＳ２ ... (Equation 5) Here, φ ＰＳ２ is the aforementioned part P Ｓ２ This is the average circular equivalent diameter of the thermoplastic resin fibers in the given location.

5. Furthermore, the artificial leather according to claim 1 or 2 satisfies the following formula 6: 0.8 × φ ＰＳ２ ≦φ ＰＣ ≤ 1.2 × φ ＰＳ２ ... (Equation 6) Here, φ ＰＳ２ is the aforementioned part P Ｓ２ This is the average circular equivalent diameter of the thermoplastic resin fibers in the given location.

6. The artificial leather according to claim 1 or 2, wherein the thermoplastic resin fiber contains a pigment, and the area ratio of the pigment in the thermoplastic resin fiber to the cross-section of the thermoplastic resin fiber is in the range of 0.01% to 13.00%.

7. The artificial leather according to claim 1 or 2, wherein the artificial leather contains a polyurethane resin.

8. The artificial leather according to claim 7, wherein the polyurethane resin contains a pigment, and the content of the pigment in the polyurethane resin is in the range of 0.1% by mass or more and 10.0% by mass or less.

9. A method for producing artificial leather according to claim 1 or 2, comprising the steps of: discharging a thermoplastic resin from the discharge hole of a die, blowing gas to include at least a portion of the area within 200 mm from the discharge hole to form a yarn, and pulling at a spinning speed of 3000 m / min or more and 7000 m / min or less to form thermoplastic resin fibers; collecting the thermoplastic resin fibers to form a fiber web; heat treating the fiber web at 70°C or more and 250°C or less to form crimped fibers from the thermoplastic resin fibers to form a crimped fiber web; and polishing or entangling at least one surface of the crimped fiber web with water.

10. The method for producing artificial leather according to claim 9, wherein in the step of forming the thermoplastic resin fibers, a pigment is added to the thermoplastic resin, and the area ratio of the pigment in the thermoplastic resin fibers to the cross-section of the thermoplastic resin fibers is in the range of 0.01% or more and 13.00% or less.

11. A vehicle interior material comprising the artificial leather described in claim 1.

12. A vehicle component comprising the artificial leather described in claim 1.

13. A seat comprising the artificial leather described in claim 1.

14. A vehicle comprising at least one of the vehicle interior material described in claim 11, the vehicle component described in claim 12, and the seat described in claim 13.

15. Clothing comprising the artificial leather described in claim 1 or 2.

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