Artificial leather, its manufacturing method, and its uses

Abstract

To provide artificial leather that offers an elegant and luxurious appearance, and excellent deformation capabilities that can conform to complex shapes such as those of vehicle parts. [Solution] An artificial leather comprising a long-fiber nonwoven fabric composed of thermoplastic resin fibers, wherein the thermoplastic resin fibers are composite fibers, and at least one surface of the artificial leather has a piled portion having a piled portion and / or a resin layer, and a portion P in a cross section parallel to the thickness direction of the artificial leather. C In this invention, the composite fiber has a region α in which the modulus of elasticity 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 modulus of elasticity 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 are connected in the order of region α, region β, region α, region β, region α, artificial leather.

Description

[Technical Field]

[0001] This invention relates to artificial leather. [Background technology]

[0002] Artificial leather that mimics the appearance of natural leather is used in a wide range of fields, including clothing, furniture, and automotive interior materials, due to its elegant appearance. Generally, such artificial leather has achieved a high level of appearance and physical properties by forming a uniform sheet from a web made of ultrafine fiber-generating short fibers (staples) using methods such as cross-layering.

[0003] For example, Patent Document 1 proposes a full-grain artificial leather comprising a base layer composed of ultrafine fibers 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. It is stated that this allows for the creation of a full-grain artificial leather that achieves both peel strength and stretchability, represented by elongation rate and elongation recovery rate.

[0004] However, in recent years, while there has been an increasing demand for even higher levels of appearance quality and physical properties, there is also a growing need for process simplification due to increased environmental consciousness.

[0005] For example, Patent Document 2 proposes an artificial leather made of a long-fiber nonwoven fabric containing fibers that hydrolyze with alkali, wherein the fibers satisfy at least one of the following properties: fiber orientation, specific gravity, and elongation, and the long-fiber nonwoven fabric is impregnated in a specific amount of a polymeric elastic material or has the grain surface attached to it. It is stated that according to this, a long-fiber nonwoven fabric that is dense yet flexible, thin and strong, and suitable for clothing applications, as well as artificial leather using this long-fiber nonwoven fabric, can be obtained at low cost. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-3181 [Patent Document 2] Japanese Patent Publication No. 2004-84076 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Even with the technology disclosed in Patent Document 1, the fact that the ultrafine fibers exhibiting a crimped structure themselves possess stretchability suggests that the process may be easier to simplify compared to artificial leather made by laminating and integrating stretchable fabrics, as in the conventional technology.

[0008] However, the technology disclosed in Patent Document 1 basically uses ultrafine fiber-generating fibers, which requires melting and extruding each of the three polymer components separately. This complicates the spinning equipment and necessitates a process to remove marine components in order to generate ultrafine fibers, leaving room for improvement in terms of productivity.

[0009] Furthermore, even with technologies like the one disclosed in Patent Document 2, in order to soften the long-fiber nonwoven fabric, it is necessary to dissolve the alkali-hydrolyzable fibers contained in the nonwoven fabric by alkali reduction processing. Therefore, there is room for improvement in terms of productivity, and also in terms of environmental impact, as it increases CO2 emissions and generates alkaline wastewater.

[0010] Therefore, the objectives of the present invention are to provide artificial leather with an elegant and high-quality appearance, excellent deformability that can conform to complex shapes such as vehicle parts, and a method for manufacturing artificial leather that can further reduce environmental impact while also improving productivity. [Means for solving the problem]

[0011] The inventors, through diligent research to solve the above problems, discovered that by using thermoplastic resin A and thermoplastic resin B, which have elastic moduli within a specific range, and obtaining a web under specific conditions, productivity in the manufacture of artificial leather can be improved, and environmental impact can be reduced. Furthermore, they found that this artificial leather has an elegant and high-quality appearance and excellent deformability, allowing it to conform to complex shapes such as those of vehicle parts.

[0012] This invention was completed based on these findings, and according to this invention, the following inventions are provided.

[0013] [1] Artificial leather comprising a long-fiber nonwoven fabric composed of thermoplastic resin fibers, The aforementioned thermoplastic resin fiber is a composite fiber, At least one surface of the artificial leather has a piled portion having a piled portion and / or a resin layer, 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 resin layer toward 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 resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. A virtual line D is drawn from the reference line of the surface having the pile portion and / or resin layer toward the reference line of the other surface at a distance of 90% of the thickness of the artificial leather, Each is drawn, and the portion from the virtual line B to the virtual line C is part P C In that case, Said part P C In this, the composite fiber is Region α, where the elastic modulus at 25°C, as measured by atomic force microscopy, is between 20 MPa and 400 MPa, Region β where the elastic modulus at 25°C measured by an atomic force microscope is 1000 MPa or more and 5000 MPa or less, and having the region α and the region β have a portion where they are connected in the order of region α, region β, region α, region β, region α, artificial leather.

[0014] [2] In the portion where the region α and the region β are connected in the order of region α, region β, region α, region β... when the number of regions β is defined as the connection number N, the artificial leather according to [1] above, which satisfies the following formula 1.

[0015] 0.1N C ≦N S1 ≦0.5N C ···(Formula 1) Here, N C is the connection number N of the composite fiber in the portion P C and N S1 is the connection number N of the composite fiber in the portion P S1 from the one surface to the virtual line A.

[0016] [3] In the portion where the region α and the region β are connected in the order of region α, region β, region α, region β... when the number of regions β is defined as the connection number N, the artificial leather according to [1] or [2] above, which satisfies the following formula 2 0.1N C ≦N S2 ≦0.5N C ···(Formula 2) Here, N C is the connection number N of the composite fiber in the portion P C and N S2 is the connection number N of the composite fiber in the portion P S2 from the virtual line D to the other surface.

[0017] [4] The portion P CThe artificial leather according to any one of [1] to [3], wherein the area ratio of the cross-section of region α to the cross-section where the composite fibers are connected is 10% or more and 40% or less.

[0018] [5] Said part P C The artificial leather according to any one of [1] to [4], wherein the area ratio of the cross-section of region β to the cross-section where the composite fibers are connected is 60% or more and 90% or less.

[0019] [6] Furthermore, The portion from one of the surfaces to the dashed line A is part P S1 , The portion from the aforementioned imaginary line D to the other surface is part P. S2 , In this case, the artificial leather described in any of [1] to [5] above satisfies the following equations 3 to 5.

[0020] 0.00≦r PS1 <0.05 (Equation 3) 0.00≦r PS2 <0.05 (Equation 4) 0.00≦r PC <0.05 (Equation 5) Here, 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, r PS2 is the aforementioned part P S2 This is the curvature of the thermoplastic resin fiber in the given context.

[0021] [7] The artificial leather according to any one of [1] to [6], wherein the composite fiber contains a pigment, and the area ratio of the pigment in the composite fiber to the cross-section of the composite fiber is in the range of 0.01% to 13.00% by mass.

[0022] [8] The artificial leather according to any one of [1] to [7], wherein the artificial leather contains polyurethane resin.

[0023] [9] The artificial leather according to [8], 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.

[0024]

[10] At least one surface of the artificial leather has a piled portion having a piled portion and / or a resin layer, In a cross-section parallel to the thickness direction of the artificial leather, A virtual line B is drawn from the reference line of the surface having the pile portion and / or resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. Each is drawn, and the portion from the virtual line B to the virtual line C is part P C In that case, Said part P C In this, the composite fiber is Region α, where the elastic modulus at 25°C, as measured by atomic force microscopy, is between 20 MPa and 400 MPa, A region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, It has, A method for manufacturing artificial leather, wherein the region α and the region β have portions that connect in the order of region α, region β, region α, region β, region α, The process involves extruding thermoplastic resin from the discharge hole of the die, then blowing gas to form a yarn including at least a portion of the area within 200 mm from the discharge hole, and then pulling the yarn at a spinning speed of 3000 m / min to 7000 m / min to form a composite fiber. The process involves collecting the aforementioned composite fibers to form a fiber web, The process includes polishing at least one surface of the fiber web to form a piled portion having raised fibers on that surface, and further, The aforementioned discharge hole is located in section P. A and section P B These are arranged alternately, The aforementioned section P A From this, thermoplastic resin A, whose elastic modulus at 25°C is measured by atomic force microscopy and is between 15 MPa and 400 MPa, is extruded. The aforementioned section P B From there, thermoplastic resin B, whose elastic modulus at 25°C is measured by atomic force microscopy to be between 1000 MPa and 5000 MPa, is extruded. The temperature of the aforementioned gas is set to be between -15°C and 50°C. A method for manufacturing artificial leather.

[0025]

[11] The method for producing artificial leather according to

[10] , wherein in the step of forming the composite 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 composite fibers to the cross-section of the composite fibers is in the range of 0.01% to 13.00%.

[0026]

[12] Vehicle interior material including artificial leather as described in any of [1] to [9] above.

[0027]

[13] A vehicle component comprising artificial leather as described in any of [1] to [9] above.

[0028]

[14] A seat comprising artificial leather as described in any of [1] to [9] above.

[0029]

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

[12] , the vehicle component described in

[13] , and the seat described in

[14] .

[0030]

[16] Clothing containing artificial leather as described in any of [1] to [9] above. [Effects of the Invention]

[0031] According to the present invention, it is possible to obtain artificial leather with an elegant and high-quality appearance and excellent deformability that can conform to complex shapes such as those of vehicle parts. Furthermore, the above manufacturing method can reduce environmental impact while improving productivity. Due to the excellent properties of this artificial leather, it can be suitably used in vehicle interior materials, automobile parts, or seats. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1 is a conceptual cross-sectional diagram illustrating the virtual lines A to D in a cross-section parallel to the thickness direction of the artificial leather according to this embodiment, as well as the parts PS1, PC, and PS2. [Figure 2] Figure 2 is a cross-sectional conceptual diagram illustrating and explaining one embodiment of the thermoplastic resin fiber (composite fiber) according to this embodiment. [Figure 3] Figure 3 is a cross-sectional conceptual diagram illustrating the method for measuring and calculating the pile length of artificial leather according to this embodiment. [Figure 4] Figure 4 is a cross-sectional conceptual diagram illustrating and explaining an example of artificial leather according to this embodiment, which has a resin layer and whose surface is substantially entirely covered by the resin layer (grain-like artificial leather). [Figure 5] Figure 5 is a cross-sectional conceptual diagram illustrating and explaining an example of artificial leather according to this embodiment, which has a resin layer and in which a part of the surface is covered with the resin layer (semi-grain artificial leather). [Figure 6] Figure 6 is a cross-sectional conceptual diagram illustrating one embodiment of the thermoplastic resin fiber (composite fiber) according to this embodiment, and in particular for explaining the number of interconnected composite fibers. [Figure 7] Figure 7 is a cross-sectional conceptual diagram illustrating the method for measuring and calculating the curvature of thermoplastic resin fibers according to this embodiment. [Figure 8] Figure 8 is a conceptual diagram showing the vicinity of the discharge holes of a nozzle as observed from the downstream side, illustrating and explaining one embodiment of the arrangement of the discharge holes of the nozzle used in the artificial leather manufacturing method according to this embodiment. [Modes for carrying out the invention]

[0033] The artificial leather of the present invention is an artificial leather comprising a long-fiber nonwoven fabric composed of thermoplastic resin fibers, The aforementioned thermoplastic resin fiber is a composite fiber, At least one surface of the artificial leather has a piled portion having a piled portion and / or a resin layer, 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 resin layer toward 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 resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. A virtual line D is drawn from the reference line of the surface having the pile portion and / or resin layer toward the reference line of the other surface at a distance of 90% of the thickness of the artificial leather, Each is drawn, and the portion from the virtual line B to the virtual line C is part P C In that case, Said part P C In this, the composite fiber is Region α, where the elastic modulus at 25°C, as measured by atomic force microscopy, is between 20 MPa and 400 MPa, A region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, It has, The region α and the region β have a portion that connects them in the order of region α, region β, region α, region β, region α.

[0034] 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.

[0035] Note that virtual lines A-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 dashed 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, which is measured and calculated by the following method, and is different from the "thickness of artificial leather" described later. <Method for measuring and calculating the "thickness of artificial leather" when drawing dashed lines> (i) Cut out a 2cm x 2cm test piece. (ii) The cross-section of the test specimen is photographed at a magnification of 200x using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). (iii) In the captured SEM image, draw a virtual line 181 passing through the tip 15 of the pile portion 12 or the end 16 of the resin portion 14, as illustrated in the cross-sectional conceptual diagram of the artificial leather shown in Figure 1, and use this as the reference line for one surface. Similarly, draw a virtual line 182 passing through the end 17 of the other surface of the artificial leather 11a or 11b, and use this as the reference line for the other surface. The virtual lines 181 and 182 should be parallel to each other and the distance between them should be maximized. This distance should be defined as the "thickness of the artificial leather" when drawing the virtual lines. Then, based on the above measurement and calculation method, draw virtual lines A to D using the following method, and section P S1 , part P C , part P S2 Identify. (i) From the reference line (virtual line 181) of one surface to the reference line (virtual line 182) of the other surface, draw virtual lines A to D as follows: • Distance 10% of the "thickness of artificial leather": Virtual line A (18A in Figure 1) • Distance of 25% of the "thickness of artificial leather": Virtual line B (18B in Figure 1) • Distance of 35% of the "thickness of artificial leather": virtual line C (18C in Figure 1) • Distance representing 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 Identify it as follows: • The portion from the reference line (virtual line 181) to virtual line A (18A in Figure 1) on one surface: Part P S1 (Figure 1, 191) • The portion from virtual line B (18B in Figure 1) to virtual line C (18C in Figure 1): Part P C (Figure 1, 192) • The portion from virtual line D (18D in Figure 1) to the reference line on the other surface (virtual line 182): Part P S2 (Figure 1, 193).

[0036] [Thermoplastic resin fibers, composite fibers] The artificial leather of one embodiment of the present invention (hereinafter also referred to as "this embodiment") includes a long-fiber nonwoven fabric made of thermoplastic resin fibers. The long-fiber nonwoven fabric includes composite fibers. Furthermore, the portion P C In this context, this composite fiber is <1> Region α, where the elastic modulus at 25°C, as measured by atomic force microscopy, is between 15 MPa and 400 MPa, <2> It has a region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, <3> The region α and the region β have a portion that connects in the order of region α, region β, region α, region β, region α. ​​This composite fiber-containing artificial leather provides an elegant and high-quality appearance, as well as excellent deformability that allows it to conform to complex shapes such as those of vehicle parts.

[0037] first, <1> Regarding the aforementioned part P CIn this embodiment, the composite fiber has a region α in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 15 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 a composite fiber having region α results in an artificial leather that is flexible, has a moderate firmness, and has the stretch to conform to complex shapes.

[0038] 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 50% by mass or more of the total 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 composite fiber, an artificial leather with excellent texture, tensile strength, and tensile elongation is produced.

[0039] 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.

[0040] 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 between 15 MPa and 400 MPa. 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 having a flexible texture and elongation that can conform to complex shapes. On the other hand, when the elastic modulus of 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 composite fiber, and consequently, an artificial leather having a moderately firm texture.

[0041] The elastic modulus and average elastic modulus of region α are measured and calculated using the following method. (i) Cut out one test piece from the artificial leather, measuring 5 mm in width and 10 mm in length, at random. (ii) The cross-section of this specimen is cut under frozen conditions using a cryomicrotome (e.g., Leica's "Ultracut-UCT") to prepare a precise cross-section of the specimen. (iii) Calibrate the probe of the atomic force microscope (for example, the Bruker Japan Co., Ltd. NanoScope V Dimension Icon probe) (for example, the Bruker Japan Co., Ltd. RTESPA-150 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) With respect to the precise cross-section of the test specimen, the portion P C AFM images will be taken of the material using an atomic force microscope. From the AFM image obtained in (v)(iv), identify the region that completely contains the cross-section of at least one fiber, and measure the elastic modulus in a 20 μm square area on the precise cross-section of the specimen using the force volume method of an atomic force microscope (a method in which the cantilever of the atomic force microscope probe is pressed against the precise cross-section of the specimen perpendicular to the cross-section and then released to obtain a force curve) to obtain an elastic modulus image. (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 within the range of the scale bar color in a single fiber cross-section is defined as region α. ​​However, in order to exclude the effects of measurement outliers and noise, a) Even in the region between 20 MPa and 400 MPa, regions smaller than 200 nm square are not considered region α. b) Within the region between 20 MPa and 400 MPa, if there is a region with a pressure of less than 20 MPa or a pressure of more than 400 MPa, if that region is less than 200 nm square, then that region shall be considered region α. (vii) In a field of view containing 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 using the force volume method, as in (v), to obtain an elastic modulus image. For the elastic modulus images obtained in (viii)(vii), the display scale for the elastic modulus is set from 20 MPa to 400 MPa, and the peak value of the obtained histogram of elastic moduli is taken as the average value (MPa) of region α. For (ix)(vii) to (viii), repeat the process in three fields of view, and round the arithmetic mean (MPa) of the average values ​​within region α of the three fields of view (the values ​​obtained in (viii)) to the first decimal place to obtain the average modulus of elasticity of region α.

[0042] 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.

[0043] next, <2> Regarding this, see Part P, which will be discussed later. CIn this embodiment, the composite fiber has a region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa. This region β plays a role in the development of high mechanical properties in the composite fiber, and by including composite fibers having region β, an artificial leather with high tensile strength and excellent abrasion resistance is obtained.

[0044] 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, the processed artificial leather becomes superior in texture and practical performance.

[0045] 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.

[0046] 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, a composite fiber with high tensile strength is obtained, resulting in artificial leather that is thin yet high-strength 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, a composite fiber with low rigidity is obtained, resulting in artificial leather with a soft, fuzzy texture.

[0047] The elastic modulus and average elastic modulus of region β are measured and calculated using the following method. (i) Cut out one test piece from the artificial leather, measuring 5 mm in width and 10 mm in length, at random. (ii) The cross-section of this specimen is cut under frozen conditions using a cryomicrotome (e.g., Leica's "Ultracut-UCT") to prepare a precise cross-section of the specimen. (iii) Calibrate the probe of the atomic force microscope (for example, the Bruker Japan Co., Ltd. NanoScope V Dimension Icon probe) (for example, the Bruker Japan Co., Ltd. RTESPA-150 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) With respect to the precise cross-section of the test specimen, the portion P C AFM images will be taken of the material using an atomic force microscope. From the AFM image obtained in (v)(iv), identify the region that completely contains the cross-section of at least one fiber, and measure the elastic modulus in a 20 μm square area on the precise cross-section of the specimen using the force volume method of an atomic force microscope (a method in which the cantilever of the atomic force microscope probe is pressed against the precise cross-section of the specimen perpendicular to the cross-section and then released to obtain a force curve) to obtain an elastic modulus image. (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 within the range of the scale bar color in a single fiber cross-section is defined as region β. However, in order to exclude the effects of measurement outliers and noise, a) Even in regions between 1000 MPa and 5000 MPa, regions smaller than 200 nm square are not considered region β. b) Within the region between 1000 MPa and 5000 MPa, if there is a region below 1000 MPa or above 5000 MPa, if that region is less than 200 nm square, then that region shall be considered region β. (vii) In a field of view containing 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 using the force volume method, as in (v), to obtain an elastic modulus image. For the elastic modulus image obtained in (viii)(vii), the display scale for the elastic modulus is set from 1000 MPa to 5000 MPa, and the peak value of the obtained elastic modulus histogram is taken as the average value (MPa) of region β. For (ix)(vii) to (viii), repeat the process in three fields of view, and round the arithmetic mean (MPa) of the average values ​​within region α of the three fields of view (the values ​​obtained in (viii)) to the first decimal place to obtain the average modulus of region β.

[0048] Furthermore, the average modulus of region β can be adjusted by factors such as the type of polymer, average molecular weight, and spinning rate.

[0049] and, <3> Regarding the aforementioned part P CIn this embodiment, the composite fiber has a portion where region α and region β are connected in the order of region α, region β, region α, region β, region α. ​​A composite fiber having this connected portion (hereinafter sometimes abbreviated as "connected portion") is, for example, a composite fiber having a cross-section as illustrated in Figure 2. In this figure, in the cross-section of any thermoplastic resin fiber, region α21 and region β22 are connected three or more times in the order of region α21, region β22, region α21, region β22, region α21 (the number of connections described later is three or more). Having such a cross-section in the composite fiber makes it possible to increase the amount of extrusion per single pore during composite spinning, as described later. Therefore, yarn breakage when spinning at high speed can be suppressed, and a high-strength fiber can be obtained, making it possible to obtain a high-strength artificial leather.

[0050] Furthermore, the aforementioned part P C In this embodiment, it is preferable that the area ratio of the cross-section of region α to the area ratio of the connected cross-sections of the composite fiber (hereinafter sometimes simply abbreviated as "area ratio of the cross-section of region α") is 10% or more and 40% or less. Being within this range results in an artificial leather that exhibits a moderate rebound when gripped, and furthermore, an artificial leather that is easy to mold to conform to a desired shape. The lower limit of the area ratio of the cross-section of region α is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, as this allows for good separation between region α and region β during spinning, resulting in an artificial leather that exhibits a moderate rebound when gripped. On the other hand, the upper limit of the area ratio of the cross-section of region α is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less, resulting in an artificial leather with better colorfastness.

[0051] And, the aforementioned part P CIn this embodiment, it is preferable that the area ratio of the cross-section of region β to the connected cross-section of the composite fiber (hereinafter sometimes simply abbreviated as "area ratio of the cross-section of region β") is 60% or more and 90% or less. Within this range, when the surface is ground during the manufacturing process of the artificial leather, a pile can be formed from region β in the composite fiber. The lower limit of the area ratio of the cross-section of region β is preferably 60% or more, more preferably 65% ​​or more, and even more preferably 70% or more, as this increases the pile density on the surface, resulting in artificial leather that exhibits a lighting effect. On the other hand, the upper limit of the area ratio of the cross-section of region β is preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less, as this results in artificial leather that exhibits a moderate rebound when gripped.

[0052] In this embodiment, the area ratio of the cross-section of region α and the area ratio of the cross-section of region β are measured and calculated by the following method. (i) Using image processing software (e.g., ImageJ) to calculate the total area of ​​region α and the total area of ​​region β within a single fiber, based on the elastic modulus images of region α in three fields obtained by the method described in the method for measuring and calculating the elastic modulus and average elastic modulus of region α (with the elastic modulus display scale set from 20 MPa to 400 MPa) and the elastic modulus images of region β in three fields obtained by the method described in the method for measuring and calculating the elastic modulus and average elastic modulus of region β (with the elastic modulus display scale set from 1000 MPa to 5000 MPa). (ii) Area S of region α in one fiber obtained α and the area S of region β β Therefore, calculate the area ratio of the cross-section of region α using the following formula (ii), and round it to the first decimal place. Area ratio of the cross-section of region α (%) = S α / (S α +S β ) × 100 ···(ii) (iii) The area ratio of the cross-section of region β is calculated using the following formula (iii). Area ratio of the cross-section of region β = 100 - Area ratio of the cross-section of region α ... (iii) Furthermore, the area ratio of the cross-section of region α and the area ratio of the cross-section of region β can be adjusted by the amount of each resin extruded during spinning.

[0053] Furthermore, in the central portion when the thickness direction of the artificial leather is divided into three parts excluding the pile portion, as described later, the equivalent circle diameter (the average single fiber diameter when the average area per region β is converted to a perfect circle, measured and calculated by the method described later; hereafter sometimes abbreviated as "equivalent circle diameter of region β") of the region β of the composite fiber according to this embodiment is preferably 2.0 μm or more and 7.0 μm or less. Being within this range results in artificial leather with a texture that has appropriate firmness and flexibility. Regarding the lower limit of the range of the equivalent circle diameter of region β, if it is 2.0 μm or more, preferably 2.5 μm or more, and more preferably 3.0 μm or more, the artificial leather will have a flexible texture. On the other hand, regarding the upper limit of the range of the equivalent circle diameter of region β, if it is 7.0 μm or less, preferably 6.0 μm or less, and more preferably 5.0 μm or less, the artificial leather will have appropriate firmness.

[0054] In this embodiment, the equivalent circular diameter (μm) of region β is measured and calculated by the following method. (i) Using image processing software (e.g., ImageJ) the average cross-sectional area per section of region β is measured for the elastic modulus images of region β in three fields (with the elastic modulus display scale set from 1000 MPa to 5000 MPa) obtained by the method described in the method for measuring and calculating the elastic modulus and average elastic modulus of region β. (ii) Convert the obtained average cross-sectional area to the diameter of the circle if it were a perfect circle of the same area, i.e., the equivalent diameter (μm), and round the arithmetic mean of the equivalent diameter (μm) to two decimal places.

[0055] Furthermore, the equivalent diameter of this region β can be adjusted by the amount of resin discharged and the spinning speed during spinning.

[0056] Furthermore, the composite fiber according to this embodiment may contain pigments. By containing pigments, the artificial leather will also have excellent lightfastness. Examples of these pigments include inorganic and organic pigments. Examples of inorganic pigments include: Black pigments such as carbon black, Blue pigments such as ultramarine blue and Prussian blue (potassium iron ferrocyanide), Red pigments such as red lead and iron oxide red, Yellow pigments such as lead yellow and zinc yellow (zinc yellow type 1, zinc yellow type 2), These are some examples. Also, as for organic pigments, Phthalocyanine, anthraquinone, quinacridone, dioxazine, isoindolinone, isoindoline, indigo, quinophthalone, diketopyrrolopyrrole, perylene, perinone, and other condensed polycyclic organic pigments. Insoluble azo compounds such as benzimidazolone, condensed azo compounds, and azomethine azo compounds. These are some examples. These can be used individually or in combination of two or more.

[0057] 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.

[0058] 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) Cut out 10 random 1cm x 1cm test pieces from the artificial leather. (ii) The cross-section of the specimen 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 bristles or the edge of the resin part 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. Next, the 25% distance and the 35% distance of the distance between virtual line 181 and virtual line 182 are determined, and the portion P of the specimen is determined. C To decide. (iii) Part P of the test specimen C Ten fibers are randomly selected from the cross-section perpendicular to the thickness direction. (iv) The cross-section of the selected fiber is imaged at a magnification of 10,000x using a scanning electron microscope (SEM, for example, the VHX-D510 model manufactured by Keyence Corporation). However, if the entire cross-section of the fiber does not fit into one field of view, five random fields of view are imaged per fiber. (v) Use image analysis software (e.g., "ImageJ") to measure the area of ​​the fiber cross-section and the area of ​​the pigmented 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 percentage (%) = (Total area of ​​pigment portion [μm²] 2 ]) / (Area of ​​fiber cross-section [μm 2 ])×100...(formula) (vii) Repeat steps (iv) to (vi) for the other nine fibers to calculate the area ratio of pigment for all fibers. (viii) Repeat steps (ii) to (vii) for the other nine test specimens, calculate the arithmetic mean (%) of the area ratio of pigment per fiber (100 fibers) of all test specimens, and round to the third decimal place.

[0059] [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 composite fibers are long fibers. Being long fibers not only results in artificial leather with high mechanical strength, but also makes it less likely for the fibers to come loose from the artificial leather, resulting in artificial leather with good abrasion resistance. Here, in this embodiment, "long fiber" means a substantially continuous fiber with a fiber length of 100 mm or more, not a short fiber that has been intentionally cut after spinning. More specifically, it means a fiber that is not a short fiber that has 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.

[0060] 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.

[0061] [Artificial leather] An artificial leather according to one embodiment of the present invention 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.

[0062] 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 observed from a 200 μm square field of view of the surface having the pile (hereinafter sometimes abbreviated as "surface fiber end count") 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.

[0063] In this invention, the number of surface fiber ends is measured and calculated by the following measurement. (i) Cut out five 2cm x 2cm test pieces at random. (ii) The surface of the specimen is made to stand upright using a lint brush or the like, and the surface is photographed in three places at a magnification of 500x using a scanning electron microscope (for example, the "VHX-D510" manufactured by Keyence Corporation). (iii) Randomly extract a 200 μm square field of view from the captured image and count the number of fiber ends. Here, "fiber end" refers to the end of a fiber that is observed independently. However, if the end of a fiber is attached to another fiber aligned in the same direction and appears as one, it will not be counted as a fiber end. (iv) Calculate the arithmetic mean of the number of fiber ends obtained from all captured images and round it to the first decimal place.

[0064] 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.

[0065] The length of the standing pile is measured and calculated by the following method. (i) Using a lint brush or the like, raise the nap of the artificial leather and prepare a 1 mm thick thin section in the cross-sectional direction of a surface perpendicular to the longitudinal direction of the artificial leather. (ii) Take a 100x magnification image of the cross-section of the artificial leather using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). (iii) In the captured SEM image, draw a virtual line 351 passing through the tip 33 of the pile portion 31, as illustrated in the conceptual cross-sectional diagram of the artificial leather shown in Figure 3, and use this as the reference line for one surface. Similarly, draw a virtual line 352 passing through the end 34 of the other surface of the artificial leather, and use this as the reference line for the other surface. The virtual lines 351 and 352 are to be parallel straight lines, and the distance between the virtual lines 351 and 352 is to be maximized. Then, according to the schematic cross-sectional diagram of the artificial leather shown in Figure 3, draw perpendicular lines S1 to S on the virtual line 351 at intervals of 200 μm. 10 Pull. (iv) Mark P1 at the point where the boundary line between the arrow portion 31 and the base portion 32 intersects with the perpendicular line S1, and mark Q1 at the point where the tip of the arrow portion 51 intersects with the perpendicular line S1. (v) Similarly, the perpendicular S2~S 10 Points P2 to P are shown above. 10 , points Q2~Q 10 Mark each of them. (vi) Let R1 be the distance between point P1 and Q1 (hair length), and similarly R 10 We calculate up to that point and then calculate the average value (arithmetic mean).

[0066] Furthermore, the pile length can be adjusted by the grit size and amount of sanding used during the pile-raising process by sandpaper grinding.

[0067] Furthermore, it is preferable that the artificial leather of this embodiment has a resin layer on at least a portion of the surface on the side having the pile portion. Such artificial leather may be, for example, as illustrated in Figure 4, in which substantially the entire surface on the side having the pile portion 41 is covered with a resin layer 43 (so-called grain-like artificial leather), or as illustrated in Figure 5, in which a portion of the surface on the side having the pile portion 51 is covered with a resin layer 53 (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 composite 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.

[0068] 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.

[0069] The resin of the resin layer according to this embodiment is preferably a polyurethane resin 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, or polyvinyl chloride. It 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, it may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. Among these resins of the resin layer, polyurethane resin is preferred from the viewpoint of flexibility and cushioning properties.

[0070] Furthermore, in this embodiment, the artificial leather preferably satisfies the following equation 1 when the number of regions β in the portion where regions α and β are connected in the order of region α, region β, region α, region β... is the number of connections N.

[0071] 0.1N C ≤N S1 ≤0.5N C ...(Formula 1) Here, N C is the aforementioned part P C In the above, the number of connected composite fibers is N, N S1 This is the portion P from one of the surfaces to the virtual line A. S1 This is the number of connections N of the composite fibers in the above-mentioned structure. As will be explained later, the number of connections N is the number of regions β that exist when the regions are connected in a chain-like fashion, as exemplified in 61a of Figure 6, starting from any region α and counting clockwise until returning to the starting region α. ​​Therefore, in the composite fiber cross-section exemplified in Figure 6, the number of connections N is the number of regions β63 adjacent to region α62, resulting in 12 in Figure 6(a) and 3 in Figure 6(b).

[0072] The aforementioned N S1Regarding the range of Equation 1 for, the lower limit is preferably 0.1 N C or more, more preferably 0.2 N C or more, resulting in a composite fiber resistant to friction, and ultimately, artificial leather with good abrasion resistance. On the other hand, the above N S1 Regarding the upper limit of the range of Equation 1 for, it is preferably 0.5 N C or less, more preferably 0.4 N C or less, resulting in a flexible composite fiber, and ultimately, artificial leather with a smooth touch of raised hair.

[0073] Further, in the artificial leather of the present embodiment, when the number of regions β in the portion where the region α and the region β are connected in the order of region α, region β, region α, region β... is defined as the connection number N, it is preferable to satisfy the following Equation 2.

[0074] 0.1 N C ≦ N S2 ≦ 0.5 N C ···(Equation 2) Here, N C is the connection number N of the composite fiber in the portion P C , and N S2 is the connection number N of the composite fiber in the portion P S2 from the virtual line D to the other surface.

[0075] In the present embodiment, the above N C , the above N S1、 N S2 is measured and calculated by the following method. (i) In the portion P C , prepare the elastic modulus images of the region α in three fields obtained by the method described in the method for measuring and calculating the elastic modulus and average elastic modulus of the region α (with the display scale of the elastic modulus from 20 MPa to 400 MPa), and the elastic modulus images of the region β in three fields obtained by the method described in the method for measuring and calculating the elastic modulus and average elastic modulus of the region β (with the display scale of the elastic modulus from 1000 MPa to 5000 MPa). (ii) Determine the number of Region β in the sequentially connected parts of the elastic modulus images of two regions in the same visual field in the order of Region α, Region β, Region α, Region β, ···. Note that when connecting like a chain, starting from an arbitrary Region α, count clockwise, and the number of Region β existing until reaching the starting Region α again is the connection number N. (iii) Repeat for the remaining two visual fields, and the value obtained by rounding to the first decimal place the arithmetic mean value of the average connection numbers of Region β in the three visual fields is Part P C The connection number N of Region β in C shall be used. (iv) By the same operation, the connection number N of Region β in Part P S1 from the one surface to the virtual line A S1 and the connection number N of Region β in Part P S2 from the virtual line D to the other surface S2 are measured.

[0076] And the artificial leather of the present embodiment further When the part from the one surface to the virtual line A is Part P S1 , When the part from the virtual line D to the other surface is Part P S2 , it is preferable to satisfy the following Formulas 3 to 5.

[0077] 0.00 ≦ r PS1 < 0.05 ··· (Formula 3) 0.00 ≦ r PS2 < 0.05 ··· (Formula 4) 0.00 ≦ r PC < 0.05 ··· (Formula 5) Here, r PS1 is the curvature of the thermoplastic resin fibers in Part P S1 , r PC is the curvature of the thermoplastic resin fibers in Part P C , r PS2 is the curvature of the thermoplastic resin fibers in Part P S2 . Furthermore, equations 3-5 must be satisfied, that is, the curvature r of the thermoplastic resin fiber PS1 , r PC , r PS2 (All values ​​are unitless) However, if all values ​​are between 0.00 and 0.05, the artificial leather will have superior strength. On the other hand, curvature r PS1 , r PC , r PS2 However, in all cases, preferably less than 0.05 (r PS1 , r PC , r PS2 <0.05), more preferably 0.04 or less (r PS1 , r PC , r PS2 ≤0.04), more preferably 0.03 or less (r PS1 , r PC , r PS2 Having a tensile strength of ≤0.03 results in artificial leather with higher tensile strength.

[0078] Furthermore, the curvature r of the thermoplastic resin fiber PS1 , r PC , r PS2 (All values ​​are unitless) are measured and calculated using the following method. (i) Cut out four 1cm x 1cm test pieces randomly from the artificial leather. (ii) The cross-section of the specimen is photographed 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, a virtual line (181 in Figure 1, hereafter simply referred to as virtual line 181) passing through the tip of the bristles or the edge of the resin part is drawn using the method described above, and a virtual line (182 in Figure 1, hereafter simply referred to as virtual line 182) passing through the edge of the other surface is drawn. Next, the 5% distance between virtual line 181 and virtual line 182 is calculated. (iii) The specimen is embedded in epoxy resin, and using a cryomicrotome (e.g., Leica "Ultracut-UCT"), a portion of the specimen P is cut from the surface having the piled or resin portion of the specimen by the distance determined in (ii). S1 A precise cross-section perpendicular to the thickness direction is fabricated. (iv) Part of the test specimen P S1 A precise cross-section perpendicular to the thickness direction is imaged at 300x magnification using a scanning electron microscope (SEM, for example, the "VHX-D510" manufactured by Keyence Corporation). (v) Select five fibers randomly from the acquired SEM images. (vi) As shown in Figure 7, measure the distance L between a 100 μm long chord 74 parallel to the baseline 73 that is in contact with the two curved portions opposite to the vertex 72 in the curved portion of the fiber, and the vertex 72, and calculate the curvature using the following formula.

[0079] Curvature (unitless) = L (μm) / 100 (μm) ... (formula) (vii) The same measurements were performed on the other test specimens, and the curvature was determined for all fibers. The arithmetic mean (unitless) of the obtained values ​​was rounded to the third decimal place to obtain the value r PS1 (Units not specified) (viii) 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 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 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, the artificial leather has good abrasion resistance. 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, the artificial leather has a flexible texture.

[0081] In this embodiment, the thickness of the resin layer is measured and calculated 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 (μm), and rounding it to the first decimal place.

[0082] Furthermore, the artificial leather of this embodiment may also preferably contain polyurethane resin. In particular, the portion P C By incorporating polyurethane resin, an artificial leather with a resilient texture is produced. Preferably, the polyurethane used is obtained by the reaction of a polymer diol, an organic diisocyanate, and a chain extender.

[0083] 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 diols, polyether diols, polycarbonate diols, or polyester polyether diols, with 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.

[0084] 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.

[0085] Generally, the polyurethane resin content in artificial leather can be adjusted as appropriate, taking into account 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.

[0086] In this invention, the percentage of polyurethane resin in artificial leather refers to the value measured and calculated by the following method. (i) Cut out five 2cm x 2cm test pieces and measure the mass of each test piece. When cutting test pieces from a product made of artificial leather, randomly select pieces from areas excluding seams and embossed parts of the product, and use them after adjusting to standard conditions of 20±2℃ and 65±4% relative humidity. (ii) The artificial leather is immersed in a solvent that elutes ultrafine fibers and reinforcing fibers, or a solvent that elutes polyurethane resin, and the polyurethane resin content (g) is calculated from the change in mass before and after elution. For example, in the case of artificial leather containing organic solvent-based polyurethane resin, the artificial leather is often immersed in N,N'-dimethylformamide to dissolve and remove the polyurethane resin, and then the polyurethane resin content (g) is calculated by measuring the mass of the remaining ultrafine fibers and reinforcing fibers. (iii) Divide the polyurethane resin content obtained in (ii) by the mass (g) of the test piece obtained in (i) to calculate the polyurethane resin content percentage (mass%). (iv)(ii) to (iii) are performed on all test specimens, and the arithmetic mean (mass%) of the polyurethane resin content (mass%) obtained is calculated and rounded to the first decimal place.

[0087] Furthermore, the polyurethane resin according to this embodiment may contain a pigment. Examples of such pigments include those described as pigments for the composite fibers.

[0088] 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.

[0089] In this embodiment, the total pigment content in the polyurethane resin is measured and calculated by the following method. (i) Total of 1m from artificial leather 2 A random sample of the test specimen is cut out, and its mass is measured. When cutting a test specimen from a product containing artificial leather, it is randomly taken from a part of the product excluding seams and embossed areas, and used after being adjusted to standard conditions of 20±2°C and 65±4% relative humidity. (ii) The test specimen is thoroughly immersed in a solvent that elutes polyurethane resin to elute the polyurethane resin. The polyurethane resin content w is then determined from the change in mass before and after elution. U The mass (g) of the reinforcing fibers, such as the remaining ultrafine fibers, is calculated. For example, in the case of artificial leather containing organic solvent-based polyurethane resin, the total content (g) of polyurethane resin and the pigment contained in the polyurethane resin is often calculated by immersing the test piece in N,N'-dimethylformamide to dissolve and remove the polyurethane resin, and then measuring the mass (g) of the remaining ultrafine fibers and other reinforcing fibers. (iii) The remaining ultrafine fibers are subjected to ultrasonic cleaning, and the pigment in the polyurethane resin attached to the ultrafine fibers is recovered by filtering the washing solution. 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) (v)(iii), (iv) Mass w of the pigment P1 (g), w P2 (g) The sum of these gives the amount of pigment in the polyurethane resin 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) (vi)(ii) to (v) are performed on all test pieces, and the arithmetic mean (mass%) of the pigment content (mass%) of the obtained polyurethane resin is calculated and rounded to the third decimal place.

[0090] [Manufacturing method for artificial leather] The method for manufacturing artificial leather according to this embodiment is as follows for artificial leather, namely, At least one surface of the artificial leather has a piled portion having a piled portion and / or a resin layer, In a cross-section parallel to the thickness direction of the artificial leather, A virtual line B is drawn from the reference line of the surface having the pile portion and / or resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. Each is drawn, and the portion from the virtual line B to the virtual line C is part P C In that case, Said part P C In this, the composite fiber is Region α where the elastic modulus at 25°C, as measured by atomic force microscopy, is between 20 MPa and 400 MPa, A region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, It has, A method for manufacturing artificial leather, wherein the region α and the region β have portions that connect in the order of region α, region β, region α, region β, region α, The process involves extruding thermoplastic resin from the discharge hole of the die, then blowing gas to form a yarn including at least a portion of the area within 200 mm from the discharge hole, and then pulling the yarn at a spinning speed of 3000 m / min to 7000 m / min to form a composite fiber. The process involves collecting the aforementioned composite fibers to form a fiber web, The process includes polishing at least one surface of the fiber web to form a piled portion having raised fibers on that surface, and further, The aforementioned discharge hole is located in section P. A and section P B These are arranged alternately, The aforementioned section P A From this, thermoplastic resin A, whose elastic modulus at 25°C is measured by atomic force microscopy and is between 15 MPa and 400 MPa, is extruded. The aforementioned section P B From there, thermoplastic resin B, whose elastic modulus at 25°C is measured by atomic force microscopy to be between 1000 MPa and 5000 MPa, is extruded. The temperature of the gas shall be between -15°C and 50°C. Details of each step are 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 invention, and it goes without saying that various modifications are possible without departing from the gist of the invention.

[0091] <Process for forming composite 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 a composite fiber.

[0092] 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 These are arranged alternately. In addition, The aforementioned section P A From this, thermoplastic resin A, whose elastic modulus at 25°C is measured by atomic force microscopy and is between 15 MPa and 400 MPa, is extruded. The aforementioned section P B From this, thermoplastic resin B, whose elastic modulus at 25°C is measured by an atomic force microscope and is between 1000 MPa and 5000 MPa, is extruded.

[0093] In this process, the discharge hole is located in section P. A and section P B These are arranged alternately. In particular, as illustrated in Figure 8, section P A and section P B It is preferable to discharge from nozzles that are alternately arranged on the circumference (in Figure 8, section P B 82B is filled 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 82A.) Furthermore, 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.

[0094] 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 Tm、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.

[0095] Furthermore, thermoplastic resin B has a melting point T m、B The melting point (°C) is preferably between 200°C and 300°C. 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 artificial leather with a uniform texture.

[0096] 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 to 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 preferably setting the temperature to 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.

[0097] 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 composite fibers.

[0098] 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 composite fiber 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.

[0099] In this embodiment, the area ratio of the pigment in the composite fiber (when measured and calculated from the composite fiber) is measured and calculated by the following method. (i) Cut out 10 random 1cm x 1cm test pieces from the artificial leather. (ii) The cross-section of the specimen 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 bristles or the edge of the resin part 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. Next, the 25% distance and the 35% distance of the distance between virtual line 181 and virtual line 182 are determined, and the portion P of the specimen is determined. C To decide. (iii) Part P of the test specimen C Ten fibers are randomly selected from the cross-section perpendicular to the thickness direction. (iv) The cross-section of the selected fiber is imaged at a magnification of 10,000x using a scanning electron microscope (SEM, for example, the VHX-D510 model manufactured by Keyence Corporation). However, if the entire cross-section of the fiber does not fit into one field of view, five random fields of view are imaged per fiber. (v) Use image analysis software (e.g., "ImageJ") to measure the area of ​​the fiber cross-section and the area of ​​the pigmented 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 percentage (%) = (Total area of ​​pigment portion [μm²] 2 ]) / (Area of ​​fiber cross-section [μm 2 ])×100...(formula) (vii) Repeat steps (iv) to (vi) for the other nine fibers to calculate the area ratio of pigment for all fibers. (viii) Repeat steps (ii) to (vii) for the other nine test specimens, calculate the arithmetic mean (%) of the area ratio of pigment per fiber (100 fibers) of all test specimens, and round to the third decimal place.

[0100] 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 written 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 AThis refers to the amount of resin (g) discharged per minute from one section. And, section P during discharge. B The 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 62 and 63.

[0101] 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 composite fibers are formed within the spinning speed range 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 a moderate rebound when gripped can be obtained, as long as composite fibers are formed within the spinning speed range described later.

[0102] 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 composite fibers are formed within the spinning speed range 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 ABy 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 composite fibers are formed within the spinning speed range described later.

[0103] 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 for the section, (section P B (Single-section discharge volume) × (Section P) B The ratio of (number of sections) can be calculated as follows: The ratio of (1) to (2) 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 increases, it becomes easier to form composite fibers that connect in the order of regions α, region β, region α, region β, region α without forming sea-island type fibers, and an artificial leather with an elegant and high-quality appearance and excellent deformability that can follow complex shapes such as vehicle parts can be obtained. On the other hand, as the single-section discharge amount of thermoplastic resin B increases, an artificial leather with high tensile strength and excellent abrasion resistance can be easily obtained.

[0104] 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.

[0105] 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 composite fibers can be suppressed, and artificial leather with a uniform touch can be obtained.

[0106] Furthermore, the temperature of the gas in this process is set to be between -15°C and 50°C. By setting the lower limit of the gas temperature range to -15°C or higher, preferably -10°C or higher, and 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 50°C or lower, preferably 40°C or lower, and more preferably 30°C or lower, the discharged yarn can be sufficiently cooled.

[0107] 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.

[0108] 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 excellent mechanical properties.

[0109] Then, the fibers are pulled at a spinning speed of 3000 m / min to 7000 m / min to form composite fibers. It is preferable to use an ejector for this pulling, and a rectangular ejector is more preferable from the viewpoint of preventing unevenness in weight distribution in the width direction.

[0110] Regarding the spinning speed, it is preferable that the spinning speed (hereinafter sometimes referred to as Vs(m / min)) be between 3000 m / min and 7000 m / min. Regarding the lower limit of the spinning speed Vs(m / min) range, 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, ensures sufficient molecular orientation of the polyester resin, resulting in a moderately firm texture, excellent mechanical properties, resistance to wrinkles and stretching, and a molded artificial leather that maintains its shape well. On the other hand, regarding the upper limit of the spinning speed Vs(m / min) range, 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, allows for more stable pulling of the gas-blown yarn, resulting in a uniformly textured artificial leather.

[0111] In this invention, the spinning speed Vs (m / min) refers to a value measured and calculated by the following method. (i) Collect the composite fibers pulled by the aforementioned threads and photograph the fiber cross-section at a magnification of 3000x using a scanning electron microscope (for example, a "VHX-D510" manufactured by Keyence Corporation). (ii) Randomly select 10 fiber cross-sections of the composite fiber, measure the cross-sectional area of ​​each composite fiber, and calculate the average cross-sectional area of ​​the composite fiber S (μm²) from the arithmetic mean. 2 Calculate ). (iii) From the discharge amounts of thermoplastic resin A and thermoplastic resin B during spinning, the discharge amount W of thermoplastic resin A per composite fiber A (g / min) and the discharge volume W of thermoplastic resin B per composite fiber. B Calculate the density (g / min). Also, the density ρ of thermoplastic resin A at 20°C. A (g / cm 3 ) 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 composite 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 rate Vs (m / min) based on the following formula and round it to the first decimal place. Vs=(W A +W B )÷F×10000 (formula).

[0112] 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 unevenness in the composite 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 unevenness in the composite fibers and a uniform touch.

[0113] 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 × 10 -3 By doing so, the aforementioned yarn can be sufficiently cooled, resulting in artificial leather with less fineness variation in the composite fibers and a uniform touch. On the other hand, the upper limit of the Vq / Vs range is preferably 30 × 10 -3 Below, 20×10 -3 More preferably 10 × 10 -3 By doing the following, the threads can be pulled more stably, and artificial leather with a uniform texture can be obtained.

[0114] <Process for forming a fiber web> In this process, the composite fibers are collected to form a fiber web.

[0115] 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.

[0116] 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.

[0117] <Process for forming a sheet substrate> The process can also include a step of forming a sheet substrate by laminating multiple fiber webs to achieve a desired basis weight, and then intertwining the fibers using a needle punching method or a water jet punching method. In this way, artificial leather with good abrasion resistance can be obtained.

[0118] Furthermore, regarding the fiber web (including those made of multiple layers), the melting point T of the thermoplastic resin A 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 composite fibers will be fused with the thermoplastic resin A or thermoplastic resin B, whichever has the lower melting point, thus making it possible to obtain artificial leather that has both a moderate rebound and flexibility when gripped.

[0119] 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 B m、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.

[0120] <Process for forming polyurethane-coated sheets> Furthermore, in the method for manufacturing artificial leather according to the present embodiment, a step of applying polyurethane to the fiber web or the sheet substrate to form a polyurethane-coated sheet may be included.

[0121] In this step, according to desired properties, 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 an aqueous dispersion type polyurethane liquid in which a mixture containing at least a polymer diol, an organic diisocyanate, and a chain extender, that is, polyurethane or its precursor, is dispersed as an emulsion in water (aqueous dispersion method) is preferably used. In the case of the former solvent method, for example, after immersing the heat-treated sheet substrate in the polyurethane solution and then drying, a method of substantially coagulating and solidifying the polyurethane precursor, or after immersing the heat-treated sheet substrate in the polyurethane solution and then immersing it in another solvent in which polyurethane is insoluble to cause coagulation can be employed. On the other hand, in the case of the latter aqueous dispersion method, for example, after immersing the heat-treated sheet substrate in the aqueous dispersion type polyurethane liquid and then drying, a method of coagulating by a dry coagulation method or the like can be used.

[0122] <Step of forming a pile portion> In this step, at least one surface of the fiber web is polished to form a pile portion having piles on the one surface. In this step, the sheet substrate and the polyurethane-coated sheet are also treated as a fiber web. Also, hereinafter, the sheet that has undergone this step may be referred to as a pile sheet.

[0123] Preferably, this polishing can be performed on at least one surface of the fiber web or the polyurethane-coated sheet using sandpaper or a roll sander. In particular, using sandpaper allows for uniform removal of regions α and β of the composite fiber. To uniformly remove regions α and β of the composite fiber, it is preferable to reduce the grinding load during 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".

[0124] <Process for applying a resin layer> The process may further include a step of providing a resin layer on at least one surface of any of the fiber web, the sheet substrate, the polyurethane-coated sheet, the pile sheet, or any of these sheets that have undergone other finishing processes described later (hereinafter referred to as "sheet-like material" in this process). Hereafter, a sheet that has undergone this process may be referred to as a resin-coated sheet.

[0125] In this process, methods for forming the resin layer include, for example, coating a molded 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 it with water and drying it, and finally bonding it to the resin layer formed on the release paper mentioned above.

[0126] 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.

[0127] 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.

[0128] <Other finishing processes> In the method for manufacturing artificial leather according to this embodiment, it is preferable to perform various 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.

[0129] 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.

[0130] 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 adding a kneading effect at the same time as dyeing can result in more flexible artificial leather. The temperature of the dyeing solution during 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 during 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.

[0131] Alternatively, various post-processing steps such as perforation, embossing, stitching, foil printing, resin printing, inkjet printing, laser etching, and lamination of films or polyurethane foam to the back of the substrate can be performed in conjunction with the molding process to improve strength and facilitate integral molding. Furthermore, woven or knitted fabrics may be further laminated onto the molded artificial leather, or onto the artificial leather before molding, provided that the deformation ability of the artificial leather is not drastically reduced, and these can be integrated by bonding or sewing.

[0132] [Uses 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, interior materials for vehicles, seats, CD curtains, DVD curtains, base materials for polishing pads, various polishing cloths, and other industrial materials.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] Furthermore, clothing containing the artificial leather described above is also preferably used because it can make use of the characteristics of being particularly excellent in flexibility and abrasion resistance. Examples of such clothing include trousers, skirts, dresses, sweaters, cardigans, jackets, coats, etc., and at least a part thereof, for example, the front body, the back body, sleeves, collars, pockets, etc. preferably contain the above artificial leather. Of course, these front bodies, etc. may be the artificial leather itself.

Examples

[0137] Next, the present invention will be specifically described based on examples. However, the present invention is not limited only to these examples.

[0138] [Measurement method] Each characteristic value in the examples was measured and calculated by the following method. In the measurement of each physical property, those without special description were measured based on the above method.

[0139] (1) Content ratio of polyurethane resin The content ratio (mass%) of the polyurethane resin in the artificial leather was measured and calculated by the above method using N,N'-dimethylformamide as a solvent for eluting the polyurethane resin.

[0140] (2) Portion P C Average elastic modulus of region α and region β at 25°C measured by atomic force microscope for thermoplastic resin fibers in Portion P C The average elastic modulus of region α and region β at 25°C measured by atomic force microscope for thermoplastic resin fibers in portion P was measured and calculated by the above method using "Ultracut-UCT" manufactured by Leica as a cryomicrotome, "NanoScope V Dimension Icon" manufactured by Bruker Japan Co., Ltd. of probe microscope as an atomic force microscope, and RTESPA type silicon probe "RTESPA-150" manufactured by Bruker Japan Co., Ltd. as a probe of the probe microscope.

[0141] (3) Part P C , P S1 , P S2 The number of connections between regions α and β in this region N C , N S1 , N S2 Part P C , P S1 , P S2 The number of connections between regions α and β in this region N C , N S1 , N S2 The (unitless) value was measured and calculated using the aforementioned scanning electron microscope "VHX-D510" and the method described above.

[0142] (4) Curvature r of thermoplastic resin fiber PS1 , r PC , r PS2 Curvature r of thermoplastic resin fibers PS1 , r PC , r PS2 (Unitless) was measured and calculated using the method described above with a scanning electron microscope, the "VHX-D510" manufactured by Keyence Corporation.

[0143] (5) Pile length, number of surface fiber ends The pile length (μm) and the number of surface end fibers were measured and calculated using the method described above, employing a scanning electron microscope, the "VHX-D510" manufactured by Keyence Corporation.

[0144] (6) Determination of whether or not a surface is provided with a resin layer, and the thickness of the resin layer. Whether or not a surface has a resin layer, and the thickness (μm) of the resin layer, were evaluated using the aforementioned method with a scanning electron microscope, specifically the "VHX-D510" model manufactured by Keyence Corporation.

[0145] (7) Weight and thickness of artificial leather Weight (g / m²) of artificial leather 2The mass was measured 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". In addition, the thickness (μm) of the artificial leather was measured using a dial thickness gauge (manufactured by Ozaki Seisakusho Co., Ltd., product name "Peacock® H").

[0146] (8) Area ratio of pigment in composite fibers to the cross-section of the composite fiber The area percentage (%) of pigment within the composite fiber cross-section 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".

[0147] (9) Appearance evaluation For artificial leather without a resin layer on the surface, the appearance quality provided by the raised nap on the surface was evaluated. The evaluation involved randomly cutting 10cm x 10cm test pieces from the artificial leather, placing them with the napped surface facing upwards, and then having 20 individuals skilled in evaluating artificial leather stroke the pieces with their fingers. The lighting effect and surface touch were then evaluated according to the following criteria, and the average score was rounded to two decimal places to obtain the evaluation score. The sum of the lighting effect score and the surface touch score was then used as the overall appearance evaluation score for the artificial leather, with a score of 6.0 or higher considered passing. [Evaluation of lighting effects] The lighting effect was evaluated when the surface of the test specimen was stroked with a finger. The lighting effect refers to the effect where the direction of the pile changes when stroked with a finger, making it appear as if the color has changed. The more pronounced the color change, the more elegant and high-quality the appearance is considered to be. The evaluation criteria are as follows. • 5 points: The marks left by the fingers are clearly visible. • 4 points: Fingerprints are visible (between 3 and 5 points) 3 points: Fingerprints are slightly faint but visible. • 2 points: Fingerprints are not visible unless you look carefully (between 1 and 3 points) • 1 point: No traces of finger stroking are visible. [Surface touch evaluation] 5 points: A moist and pleasant texture • 4 points: Smooth texture (between 3 and 5 points) 3 points: Smooth texture • 2 points: Slightly rough texture (between 1 and 3 points) • 1 point: Feels rough. Furthermore, for artificial leather with a resin layer on its surface, the appearance quality provided by the resin layer was evaluated. For the evaluation, 10cm x 10cm test pieces were randomly cut from the artificial leather, placed with the resin-coated surface facing upwards, and folded in half so that the resin-coated surface was on the outside. A 6cm x 6cm flat plate was gently placed over the entire surface of the folded test piece, and an additional weight was gently placed on top of the plate to apply a load so that the total mass of the plate and weight was 4.0kg. After applying the load for 30 seconds, the plate and weight were removed, and 10 seconds later, 20 people skilled in evaluating artificial leather evaluated the wrinkle condition of the bent part according to the following four criteria. The average score was rounded to two decimal places to obtain the evaluation score, and a score of 2.6 or higher was considered a passing grade. [Condition of creases from folding] • 4 points: No wrinkles are visible in the bent part. • 3 points: Wrinkles can be seen when carefully examining the bent part. • 2 points: There is a slight mark visible on the bent part. • 1 point: Deep wrinkles are visible in the bent area.

[0148] (10) 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.

[0149] (11) 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.

[0150] (12) Elongation at a load of 5 N / cm As an indicator of the moldability of artificial leather, a tensile test was conducted in accordance with "Method A (Strip Method)" of "8.14 Tensile Strength and Elongation" of "8.14.1 JIS Method" in JIS L1096:2020 "Test Methods for Woven and Knitted Fabrics," with a test specimen width of 25 mm, gripping distance of 100 mm, and tensile speed of 100 mm / min. The elongation (%) at a load of 12.5 N was defined as the elongation (%) at 5 N / cm.

[0151] [Thermoplastic resin] The following thermoplastic resins were used in the examples and comparative examples. Hereafter, including in the table, abbreviations may be used as indicated at the beginning. PET1: Polyethylene terephthalate (homopolymer, melting point: 260°C, modulus of elasticity at 25°C measured by atomic force microscopy: 2030 MPa, intrinsic viscosity (IV): 0.65) PET2: PET1 with added carbon black to achieve a pigment content of 5.0% by mass. TPE1: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 4057N (manufactured by Toray Celanese Co., Ltd., melting point: 163°C, modulus of elasticity at 25°C measured by atomic force microscope: 55 MPa) TPE2: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 4767N (manufactured by Toray Celanese Co., Ltd., melting point: 199°C, modulus of elasticity at 25°C measured by atomic force microscope: 93 MPa) TPE3: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 6347 (manufactured by Toray Celanese Co., Ltd., melting point: 215°C, modulus of elasticity at 25°C measured by atomic force microscope: 234 MPa) TPE4: Polyester-based thermoplastic elastomer "Hytrel" (registered trademark) 2751 (manufactured by Toray Celanese Co., Ltd., melting point: 227°C, modulus of elasticity at 25°C measured by atomic force microscope: 692 MPa) PA6: Polyamide 6 (relative viscosity of sulfuric acid: 2.45, melting point: 225°C, modulus of elasticity at 25°C measured by atomic force microscopy: 2517 MPa).

[0152] [Example 1] (Process for forming composite fibers) As the thermoplastic resin A that forms region α, TPE1 is used in section P A The single-compartment discharge rate is 0.36 g / (min / compartment), and PET1 is used as the thermoplastic resin B that forms region β, and compartment P B The single-compartment discharge rate was set to 1.20 g / (min / compartment), and the contents were combined in a hollow annular petal-shaped 24-segment / split-fiber nozzle and discharged from the discharge hole of the nozzle. This discharge hole is located in compartment P, as illustrated in Figure 8. A and section P B A configuration in which and are arranged alternately was used. Also, at this time, the sum of the single-section discharge volumes of thermoplastic resin A in the total discharge volume is the total discharge volume of all sections, (section 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 (this is the total discharge amount for all sections, (section P B (Single-section discharge volume) × (Section P) B It can be calculated using the number of sections. The ratio of (hereinafter, including in the table, it may be abbreviated as "discharge rate ratio") was 23:77.

[0153] Subsequently, in the region 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 the yarn. At a spinning speed Vs = 4600 m / min, the yarn was pulled with 15°C air to form composite fibers. The distance between the discharge port and the inlet was 700 mm.

[0154] (Process of forming a fiber web) Then, the composite fibers were collected on a moving net conveyor under suction to form a fiber web.

[0155] (Process for forming a sheet substrate) The resulting basis weight was 101 g / m². 2 After laminating two fiber webs, they were treated twice each on the front and back sides using a water jet punch (hereinafter abbreviated as WJP, including in the table) at pressures of 7 MPa and 10 MPa, followed by drying with hot air at 100°C. Furthermore, with the surface temperature of the top plate at 180°C and the surface temperature of the bottom plate at 180°C, the apparent density after hot pressing was 0.25 g / cm³. 3 A clearance was created to achieve this, and the sheet base was formed by applying a heat press for 10 seconds.

[0156] (Process for forming polyurethane-coated sheets) First, a water-dispersible polyurethane solution containing a polyetherdiol and an organic diisocyanate was prepared. The sheet substrate obtained above was immersed in this water-dispersible polyurethane solution, and then dried with hot air at 120°C to obtain a polyurethane-coated sheet with a polyurethane resin content of 30% by mass.

[0157] (Process for forming the arranging part) One surface of the obtained polyurethane-coated sheet was polished with 320-grit sandpaper to form a piled area on that surface, thereby creating a piled sheet.

[0158] (Other finishing processes) Artificial leather was obtained by dyeing the obtained pile sheet with a dyeing solution prepared in a ratio of 15 parts by mass of disperse dye (Dianix Black CC-R, manufactured by Dystar Japan Co., Ltd.) per 100 parts by mass of pile sheet, using a jet dyeing machine with the dyeing solution temperature set to 130°C. The results are shown in Table 1.

[0159] [Example 2] (In the process of forming composite fibers), section P A Artificial leather was obtained in the same manner as in Example 1, except that the single-compartment discharge rate was set to 0.60 g / (min / compartment) and the discharge rate ratio was changed to 33:67. The results are shown in Table 1.

[0160] [Example 3] Artificial leather was obtained in the same manner as in Example 1, except that thermoplastic resin A was changed to TPE2 in the process of forming composite fibers. The results are shown in Table 1.

[0161] [Example 4] Artificial leather was obtained in the same manner as in Example 2, except that thermoplastic resin A was changed to TPE3 in the process of forming composite fibers. The results are shown in Table 1.

[0162] [Comparative Example 1] (The process of forming fibers) Molten PET was discharged from the nozzle at a single-hole discharge rate of 0.10 g / min. The discharge hole used had a diameter of 0.10 mm and a perfectly circular shape.

[0163] Subsequently, in the region 50 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 the yarn. At a spinning speed Vs = 4600 m / min, the yarn was pulled with 15°C air to form single-component fibers. The distance between the discharge port and the inlet was 700 mm.

[0164] (Process of forming a fiber web) Then, the single-component fibers were collected on a moving net conveyor under suction to form a fiber web.

[0165] (Process for forming a sheet substrate) The resulting basis weight was 98 g / m². 2 After laminating two fiber webs, they were treated twice each on the front and back sides using a WJP (Wet Pressing Machine) at pressures of 7 MPa and 10 MPa, followed by drying with hot air at 100°C. Furthermore, the surface temperature of the top plate was set to 180°C and the surface temperature of the bottom plate to 180°C, and the apparent density after hot pressing was 0.25 g / cm³. 3 A clearance was created to achieve this, and the sheet base was formed by applying a heat press for 10 seconds.

[0166] (Process for forming polyurethane-coated sheets) First, a water-dispersible polyurethane solution containing a polyetherdiol and an organic diisocyanate was prepared. The sheet substrate obtained above was immersed in this water-dispersible polyurethane solution, and then dried with hot air at 120°C to obtain a polyurethane-coated sheet with a polyurethane resin content of 30% by mass.

[0167] (Process for forming the arranging part) One surface of the obtained polyurethane-coated sheet was polished with 320-grit sandpaper to form a piled area on that surface, thereby creating a piled sheet.

[0168] (Other finishing processes) Artificial leather was obtained by dyeing the resulting piled sheet with disperse dyes at 130°C using a jet dyeing machine. The results are shown in Table 1.

[0169] [Comparative Example 2] (In the process of forming composite fibers), thermoplastic resin A is converted to PA6, and section P A Artificial leather was obtained in the same manner as in Example 1, except that the single-compartment discharge rate was changed to 1.20 g / (min / compartment) and the discharge rate ratio was changed to 50:50. The results are shown in Table 1.

[0170] [Comparative Example 3] Artificial leather was obtained in the same manner as in Example 1, except that thermoplastic resin A was changed to TPE4 in the process of forming composite fibers. The results are shown in Table 1.

[0171] [Example 5] (Process for forming composite fibers) ~ (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.

[0172] (Step of applying a 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, along with a carbon black-based black pigment, was mixed in a mixer to prepare a resin liquid for forming a resin layer. This resin liquid was applied in a sheet-like manner to release paper having a textured surface using a comma coater, and then treated in a dryer at 100°C for 3 minutes to form a non-porous resin film with a thickness of 80 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. The adhesive-coated surface was placed on the surface of the dyed pile sheet having a piled portion, with the resin layer facing upwards, and pressed together by dry heat pressing 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. After that, the release paper was peeled off to obtain artificial leather with a resin layer formed on the surface. The results are shown in Table 2.

[0173] [Comparative Example 4] (Process for forming composite fibers) ~ (Other finishing processes) A pile sheet was formed in the same manner as in Comparative Example 2, and this pile sheet was dyed using a disperse dye in a jet dyeing machine at 130°C.

[0174] (Step of applying a resin layer) Artificial leather was obtained by forming a resin layer on the surface in the same manner as in Example 5. The results are shown in Table 2.

[0175] [Example 6] Artificial leather was obtained in the same manner as in Example 1, except that thermoplastic resin B was changed to PET2 in the (compound fiber formation process) and the process was carried out using a liquid jet dyeing machine without using dyes in the (other finishing process). The results are shown in Table 3.

[0176] [Example 7] Artificial leather was obtained in the same manner as in Example 6, except that in the process of forming the 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. 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 3.

[0177] [Comparative Example 5] Artificial leather was obtained in the same manner as in Comparative Example 3, 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 3.

[0178] [Comparative Example 6] Artificial leather was obtained in the same manner as in Example 6, except that thermoplastic resin A was replaced with TPE4 in the process of forming the composite fibers. The results are shown in Table 3.

[0179] [Table 1]

[0180] [Table 2]

[0181] [Table 3]

[0182] As shown in Table 1, the artificial leathers with raised nap on the surface of Examples 1 to 4 exhibited an elegant and high-quality appearance and excellent deformability, allowing them to conform to complex shapes such as those of vehicle parts. On the other hand, the artificial leather of Comparative Example 1 had good appearance quality but poor moldability. Furthermore, the artificial leathers of Comparative Examples 2 and 3 were inferior in both appearance quality and moldability.

[0183] Furthermore, as shown in Table 2, the artificial leather with a resin layer on the surface of Example 5 also exhibited excellent deformation capabilities, remaining wrinkled when folded, resulting in an elegant and high-quality appearance, and being able to conform to complex shapes such as those of vehicle parts. On the other hand, Comparative Example 4 remained wrinkled after deformation, resulting in inferior appearance changes.

[0184] Furthermore, as shown in Table 3, the artificial leathers of Examples 7 and 8, which have a piled surface and also contain pigment in the composite fibers, exhibited an elegant and high-quality appearance, excellent deformability that could conform to complex shapes such as vehicle parts, and excellent lightfastness. On the other hand, the artificial leathers of Comparative Examples 5 and 6 were inferior in both appearance quality and moldability, and the artificial leather of Comparative Example 5 also showed inferior lightfastness. [Explanation of symbols]

[0185] 1: Area α 2: Area β 11a: Cross-section of artificial leather with a raised nap on the surface 11b: Cross-section of artificial leather having a resin layer on the surface 12: Pierrection part 13: Base part 14: Surface resin part 15: Tip of the piloerection part 16: Surface resin edge 17: The other surface end 181: Reference line on one surface 182: Reference line of the other surface 191: Part P S1 192: Part P C 193: Part P S2 18A: A virtual line located at a distance of 10% of the thickness of the artificial leather, from the surface having the pile or resin layer toward the other surface. 18B: A virtual line located at a distance of 25% of the thickness of the artificial leather, from one surface having a pile or resin layer toward the other surface. 18C: A virtual line located at a distance of 35% of the thickness of the artificial leather, from the surface having the pile or resin layer toward the other surface. 18D: A virtual line located at a distance of 90% of the thickness of the artificial leather, from one surface having a pile or resin layer to the other surface. 21: Area α 22: Area β 31: Pierrection part 32: Base part 33: Tip of the arranging hair 34: Edge of the other surface 351: Reference line at the tip of the arrowing hair 352: Reference line of the other surface 41: Pierrection part 42: Base part 43: Surface resin layer 51: Pierrection part 52: Base part 53: Resin layer covering a portion of the surface on the side of the arranging pile 61: Composite Fibers 62: Area α 63: Area β 71: Fibers 72: The apex of the curved section 73: Baselines touching two curved sections opposite the apex of the curved section. 74: A 100 μm long string parallel to baseline 73. 81: Nozzle discharge surface 82: Nozzle discharge hole L: Distance between 71 and 74 P n : Points on the boundary line between the arrowhead and the base (n=1~10) Q n : Points at the tips of the upright hairs (n=1~10) R n : Hair length (n=1~10) S n: Perpendicular line to the reference line at the tip of the arranging hair (n=1~10)

Claims

1. Artificial leather comprising a long-fiber nonwoven fabric composed of thermoplastic resin fibers, The aforementioned thermoplastic resin fiber is a composite fiber, The artificial leather has a piled portion having a piled portion and / or a resin layer on at least one surface, 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 resin layer toward 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 resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. A virtual line D is drawn from the reference line of the surface having the pile portion and / or resin layer toward the reference line of the other surface at a distance of 90% of the thickness of the artificial leather. Each is drawn, and the portion from the virtual line B to the virtual line C is part P Ｃ In that case, Said part P Ｃ In this, the composite fiber is 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, A region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, It has, The region α and the region β have a portion that connects in the order of region α, region β, region α, region β, region α. Artificial leather.

2. The artificial leather according to claim 1, wherein when the number of regions β in the portion where regions α and β are connected in the order of region α, region β, region α, region β... is the number of connections N, the following equation 1 is satisfied. 0.1N Ｃ ≦N Ｓ１ ≤0.5N Ｃ ... (Form 1) Here, N Ｃ is the aforementioned part P Ｃ In the above, the number of connected composite fibers N is, N Ｓ１ is the number N of connections of the composite fiber in the portion P from the one surface to the virtual line A Ｓ１ in the above.

3. The artificial leather according to claim 1 or 2, wherein when the number of regions β in the portion where region α and region β are connected in the order of region α, region β, region α, region β... is the number of connections N, the following equation 2 is satisfied. 0.1N Ｃ ≦N Ｓ２ ≤0.5N Ｃ ... (Formula 2) Here, N Ｃ is the aforementioned part P Ｃ In the above, the number of connected composite fibers N is, N Ｓ２ This is the portion P from the virtual line D to the other surface. Ｓ２ This is the number of interconnected composite fibers N.

4. Said part P Ｃ The artificial leather according to claim 1 or 2, wherein the area ratio of the cross-section of region α to the cross-section where the composite fibers are connected is 10% or more and 40% or less.

5. Said part P Ｃ The artificial leather according to claim 1 or 2, wherein the area ratio of the cross-section of region β to the cross-section where the composite fibers are connected is 60% or more and 90% or less.

6. moreover, The portion from one of the surfaces to the dashed line A is part P Ｓ１ , The portion from the aforementioned virtual line D to the other surface is part P. Ｓ２ , In this case, the artificial leather according to claim 1 or 2 satisfies the following formulas 3 to 5. 0.00≦r ＰＳ１ <0.05 ・・・(Equation 3) 0.00≦r ＰＳ２ <0.05 ・・・(Equation 4) 0.00≦r ＰＣ <0.05 ・・・(Equation 5) Here, 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, r ＰＳ２ is the aforementioned part P Ｓ２ This is the curvature of the thermoplastic resin fiber in the given context.

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

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

9. The artificial leather according to claim 8, 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.

10. The artificial leather has a piled portion having a piled portion and / or a resin layer on at least one surface, In a cross-section parallel to the thickness direction of the artificial leather, A virtual line B is drawn from the reference line of the surface having the pile portion and / or resin layer toward 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 resin layer toward the reference line of the other surface at a distance of 35% of the thickness of the artificial leather. Each is drawn, and the portion from the virtual line B to the virtual line C is part P Ｃ In that case, Said part P Ｃ In this, the composite fiber is 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, A region β in which the elastic modulus at 25°C, as measured by an atomic force microscope, is between 1000 MPa and 5000 MPa, It has, A method for manufacturing artificial leather, wherein the region α and the region β have portions that connect in the order of region α, region β, region α, region β, region α, The process involves extruding a thermoplastic resin from the discharge hole of the die, then blowing gas to form a yarn, including at least a portion of the area within 200 mm from the discharge hole, and then pulling the yarn at a spinning speed of 3000 m / min to 7000 m / min to form a composite fiber. The process involves collecting the aforementioned composite fibers to form a fiber web, The process includes polishing at least one surface of the fiber web to form a piled portion having raised fibers on that surface, and further, The aforementioned discharge hole is located in section P. Ａ and section P Ｂ These are arranged alternately, The aforementioned section P Ａ From this, a thermoplastic resin A, whose elastic modulus at 25°C is measured by an atomic force microscope and is between 15 MPa and 400 MPa, is extruded. The aforementioned section P Ｂ From there, thermoplastic resin B, whose elastic modulus at 25°C is measured by atomic force microscopy and is between 1000 MPa and 5000 MPa, is extruded. The temperature of the aforementioned gas is set to be between -15°C and 50°C. A method for manufacturing artificial leather.

11. A method for producing artificial leather according to claim 10, wherein in the step of forming the composite 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 composite fibers to the cross-section of the composite fibers is in the range of 0.01% to 13.00%.

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

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

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

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

16. Clothing comprising artificial leather as described in claim 1 or 2.

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