artificial leather

Abstract

The purpose of the present invention is to provide a natural leather-like artificial leather with a pattern, which can also be applied to artificial leather containing black pigment in ultrafine fibers or polymer elastomers with excellent wear resistance and fine design. The artificial leather of the present invention includes a fiber winding body and a polymer elastomer, and the fiber winding body contains a non-woven fabric composed of ultrafine fibers with an average single fiber diameter of 1 to 10 μm and containing a thermoplastic resin as a component. At least one surface of the artificial leather is a design surface having at least a raised portion and a fusion portion. When the content of the thermoplastic resin in the raised portion is set to 100 parts by mass, the content of the thermoplastic resin in the fusion of the fusion portion is 99 to 100 parts by mass, and the difference between the thickness of the raised portion and the thickness of the fusion portion is 0.05 to 0.20 mm, and the following formulas (1) to (3) are satisfied respectively. ΔE* ab ≧5…(1)0≦ΔH* ab ≦1…(2)2D≦φ≦150…(3)

Description

Technical Field

[0001] The present invention relates to artificial leather, in particular to an artificial leather provided with a fine and well-designed pattern and having excellent abrasion resistance. Background Art

[0002] Artificial leather, primarily composed of a fiber-entangled structure composed of a nonwoven fabric made of ultrafine fibers containing a thermoplastic resin and a polymer elastomer, offers superior characteristics compared to natural leather, such as high durability and uniform quality. It is used not only as a raw material for clothing but also in various fields, including vehicle interior materials, interior trim, shoes, and clothing. In recent years, due to the diversification of consumer demands, demand for artificial leather with patterned surfaces and higher design qualities has increased in all fields.

[0003] Printing and embossing are generally known methods for imparting patterns to artificial leather. While printing allows for a flexible pattern to be applied to artificial leather, it also requires improved wear resistance for printed patterns in applications such as interior materials for vehicles and homes, which are susceptible to wear during use. Embossing, on the other hand, can yield artificial leather with relatively excellent wear resistance, but it is difficult to produce fine patterns or a wide variety of products. Furthermore, embossing heats the entire artificial leather, resulting in a degraded texture.

[0004] Therefore, in order to improve the wear resistance of the above-mentioned pattern or the deterioration of the feel, the following method is proposed: printing black pigments such as graphite and carbon black on the raised surface of artificial leather, and then heating and melting only the fibers of the black pigment printed part by infrared irradiation, thereby fixing the black pigment on the fibers and forming dark recesses.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2001-371478 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, the technology disclosed in Patent Document 1 has the following problems: each pattern requires plate making, which takes time to correct or change the pattern, and it is difficult to express delicate patterns. In addition, it is not applicable to black solution-dyed fibers designed to contain black pigment in the fiber itself to improve dye fastness, or artificial leather designed to contain black pigment in the polymer elastomer to achieve uniform color development.

[0010] Therefore, the present invention is made in view of the above situation, and its purpose is to provide a patterned natural leather-like artificial leather that can also be used for the following artificial leather, wherein the artificial leather includes a fiber winding body and a polymer elastomer, and the fiber winding body contains a non-woven fabric composed of ultrafine fibers containing a thermoplastic resin as a constituent element, in which the artificial leather has a pattern with excellent wear resistance and excellent slender design, and contains black pigment in the ultrafine fibers or the polymer elastomer.

[0011] Technical means to solve the problem

[0012] The present inventors have conducted repeated studies to achieve the above-mentioned purpose. As a result, the present inventors have found that: at least one surface of the artificial leather is provided with a design surface having a pile portion and a fusion portion, the content ratio of the thermoplastic resin in the fusion portion is set to a specific ratio, the difference between the thickness of the pile portion and the thickness of the fusion portion, the color difference ΔE* between the pile portion and the fusion portion are controlled, and the color difference ΔE* between the pile portion and the fusion portion is controlled. ab and hue difference ΔH* ab , and the size of the fusion product is set within a specific range, thereby obtaining an artificial leather that exhibits a slender design and excellent wear resistance.

[0013] The present invention has been accomplished based on the above findings, and the present invention can provide the following inventions.

[0014] That is, the artificial leather of the present invention includes a fiber winding body and a polymer elastomer, and the fiber winding body contains a non-woven fabric composed of ultrafine fibers with an average single fiber diameter of 1 μm to 10 μm and containing a thermoplastic resin as a constituent element, wherein at least one surface of the artificial leather is a designed surface having at least a raised portion and a fusion portion, and when the content of the thermoplastic resin in the raised portion is set to 100 parts by mass, the content of the thermoplastic resin in the fusion product of the fusion portion is 99 parts by mass to 100 parts by mass, and the difference between the thickness of the raised portion and the thickness of the fusion portion is 0.05 mm to 0.20 mm, and respectively satisfies the following formulas (1) to (3).

[0015] ΔE* ab ≧5…(1)

[0016] 0≦ΔH* ab ≦1…(2)

[0017] 2D≦φ≦150…(3)

[0018] Where, ΔE* ab It is the International Commission on Illumination (CIE) LAB1976 L*a*b* color difference between the raised part and the fused part, ΔH* abis the CIELAB 1976 hue difference between the raised portion and the fused portion, D is the average single fiber diameter (μm) of the ultrafine fibers, and φ is the size (μm) of the fused product.

[0019] According to a preferred embodiment of the artificial leather of the present invention, the ultrafine fibers further contain a black pigment in addition to the thermoplastic resin.

[0020] According to a preferred embodiment of the artificial leather of the present invention, the elastic polymer contains a black pigment.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to obtain an artificial leather that exhibits a delicate design and is excellent in abrasion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram illustrating and explaining a method for measuring the difference between the thickness of the napped portion and the thickness of the fused portion.

[0024] Figure 2 This is a diagram illustrating and explaining the method for measuring the size φ of a fusion.

[0025] [Explanation of Symbols]

[0026] A: The highest point in the thickness direction of the artificial leather

[0027] B: The lowest point in the thickness direction of the artificial leather

[0028] C: Example 1 of Determination of Fusion Size

[0029] D: Example 2 of Determination of Fusion Size

[0030] E: Example 3 of Determination of Fusion Size

[0031] F: Example 4 of Determination of Fusion Size DETAILED DESCRIPTION

[0032] The artificial leather of the present invention includes a fiber winding body and a polymer elastomer, wherein the fiber winding body contains a non-woven fabric composed of ultrafine fibers with an average single fiber diameter of 1 μm to 10 μm and containing a thermoplastic resin as a constituent element, and at least one surface of the artificial leather is a designed surface having at least a raised portion and a fusion portion, and when the content of the thermoplastic resin in the raised portion is set to 100 parts by mass, the content of the thermoplastic resin in the fusion portion is 99 parts by mass to 101 parts by mass, and the difference between the thickness of the raised portion and the thickness of the fusion portion is 0.05 mm to 0.20 mm, and respectively satisfies the following formulas (1) to (3).

[0033] ΔE* ab≧5…(1)

[0034] 0≦ΔH* ab ≦1…(2)

[0035] 2D≦φ≦150…(3)

[0036] Here, ΔE* ab is the CIELAB1976L*a*b* color difference between the raised part and the fused part, ΔH* ab is the CIELAB 1976 hue difference between the raised portion and the fused portion, D is the average single fiber diameter of the ultrafine fibers (μm), and φ is the size of the fused product (μm). These components are described in detail below, but the present invention is not limited to the scope of the following description as long as it does not exceed the scope of the present invention.

[0037] [Fiber winding body]

[0038] As thermoplastic resins used in the ultrafine fibers of the present invention, any resin that can be formed into a fiber form, such as "polyethylene terephthalate, polybutylene terephthalate, and polyester elastomers," polyamide resins such as "polyamide 6, polyamide 66, and polyamide elastomers," polyurethane resins, polyolefin resins, and acrylonitrile resins, can be used. However, from the perspective of durability, especially mechanical strength, heat resistance, etc., polyester resins can be preferably used.

[0039] Examples of the polyester resin include polyethylene terephthalate, polyethylene trimethylene terephthalate, polyethylene tetramethylene terephthalate, polyethylene cyclohexylene dimethylene terephthalate, polyethylene 2,6-naphthalene dicarboxylate, and polyethylene 1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate. Among these, polyethylene terephthalate, which is the most commonly used, or a polyester copolymer primarily comprising ethylene terephthalate units is preferably used.

[0040] In addition, as the polyester resin, a single polyester or two or more different polyesters may be used. However, when two or more different polyesters are used, from the perspective of compatibility of the two or more components, the difference in intrinsic viscosity (IV value) of the polyesters used is preferably 0.50 or less, and more preferably 0.30 or less.

[0041] In the present invention, the intrinsic viscosity is calculated by the following method.

[0042] (1) 0.8 g of a sample polymer was dissolved in 10 mL of o-chlorophenol.

[0043] (2) Using an Ostwald viscometer at 25°C, the relative viscosity η was calculated using the following formula: r, rounded to the third decimal place.

[0044] η r =η / η0=(t×d) / (t0×d0)

[0045] Intrinsic viscosity (IV value) = 0.0242η r +0.2634

[0046] (Here, η represents the viscosity of the polymer solution, η0 represents the viscosity of o-chlorophenol, t represents the falling time of the solution (seconds), and d represents the density of the solution (g / cm 3 ), t0 represents the falling time of o-chlorophenol (seconds), d0 represents the density of o-chlorophenol (g / cm 3 )).

[0047] The average single fiber diameter of the ultrafine fibers of the present invention is 1 μm or more and 10 μm or less. By setting the average single fiber diameter of the ultrafine fibers to 1.0 μm or more, preferably 1.5 μm or more, excellent color development after dyeing, light fastness, friction fastness, and stability during spinning can be achieved. On the other hand, by setting the average single fiber diameter to 10.0 μm or less, preferably 6.0 μm or less, and more preferably 5.0 μm or less, a dense, soft-touch artificial leather with excellent surface quality can be obtained.

[0048] In the present invention, the so-called average single fiber diameter of ultrafine fibers is set as the following average single fiber diameter: by taking a scanning electron microscope (SEM, such as "VHX-D500 / D510" or "VE-7800" manufactured by KEYENCE Co., Ltd.) photograph of the cross-section of artificial leather, 10 circular or nearly circular elliptical ultrafine fibers are randomly selected, the single fiber diameter is measured and the arithmetic mean of the 10 fibers is calculated, and the result is rounded off to the second decimal place.

[0049] Furthermore, the cross-sectional shape of the ultrafine fibers of the present invention is preferably a circular cross-section from the viewpoint of processability, but may also have an elliptical, flat, triangular or other polygonal shape, a fan-shaped, a cross-shaped, a hollow shape, a Y-shaped, a T-shaped, or a U-shaped cross-section. In such cases, the average single fiber diameter of the ultrafine fibers is determined by first measuring the cross-sectional area of ​​the single fibers and calculating the diameter if the cross-section were considered to be circular, thereby determining the single fiber diameter.

[0050] In the present invention, particularly when artificial leather is to be dark colored, the polyester resin constituting the ultrafine fibers preferably contains a black pigment or a colored fine-particle oxide pigment having an average particle size of 0.05 μm to 0.20 μm.

[0051] The particle size mentioned here refers to the particle size of the black pigment or the color fine-particle oxide pigment in a state where the black pigment or the color fine-particle oxide pigment exists in the ultrafine fibers, and refers to a particle size generally called a secondary particle size.

[0052] By setting the average particle size to preferably 0.05 μm or greater, more preferably 0.07 μm or greater, the black pigment or colored fine-particle oxide pigment is retained within the ultrafine fibers, thereby preventing it from falling out of the ultrafine fibers. Furthermore, by setting the average particle size to preferably 0.20 μm or less, more preferably 0.18 μm or less, and even more preferably 0.16 μm or less, excellent spinning stability and yarn strength are achieved.

[0053] The content (A) of the black pigment or colored fine-particle oxide pigment contained in the polyester resin forming the microfiber is preferably set to 0.5% by mass or more and 2.0% by mass or less relative to the mass of the microfiber. By setting the pigment ratio to preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and even more preferably 0.9% by mass or more, excellent deep color rendering is achieved. By setting the pigment ratio to preferably 2.0% by mass or less, more preferably 1.8% by mass or less, and even more preferably 1.6% by mass or less, artificial leather with high physical properties such as strength and elongation can be produced.

[0054] As the black pigment used in the present invention, carbon-based black pigments such as carbon black or graphite, or oxide-based black pigments such as composite oxides of ferrosoferric oxide, copper, and / or chromium, can be used. Carbon black is preferred because it is easy to obtain a fine-particle black pigment and has excellent dispersibility in polymers.

[0055] The colored fine-particle oxide pigment in the present invention refers to a colored pigment among fine-particle oxide pigments, and white oxide pigments such as zinc oxide and titanium oxide are not included in the colored fine-particle oxide pigments.

[0056] Colored particulate oxide pigments can use known pigments close to the target color, and examples thereof include iron hydroxyhydroxide (such as "TM Yellow 8170" manufactured by Dainichi Seika Co., Ltd.), iron oxide (such as "TM Red 8270" manufactured by Dainichi Seika Co., Ltd.), and cobalt aluminate (such as "TM Blue 3490E" manufactured by Dainichi Seika Co., Ltd.).

[0057] Furthermore, inorganic particles such as titanium oxide particles, lubricants, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antimicrobial agents may be added to the thermoplastic resin forming the ultrafine fibers as needed within a range that does not hinder the purpose of the present invention.

[0058] The artificial leather of the present invention includes a fiber entanglement body containing a nonwoven fabric composed of ultrafine fibers containing the thermoplastic resin as one of the components.

[0059] In the present invention, the so-called "fiber winding body containing non-woven fabric as a constituent element" means a form in which the fiber winding body is in the form of non-woven fabric, a form in which the fiber winding body is formed by intertwining and integrating non-woven fabric and fabric as described later, and a form in which the fiber winding body is formed by intertwining and integrating non-woven fabric and a substrate other than fabric.

[0060] By forming a fiber-entangled body containing a nonwoven fabric as a component, a uniform and elegant appearance or feel can be obtained when the surface is raised.

[0061] Nonwoven fabrics can be formed into long-fiber nonwovens primarily composed of filaments and short-fiber nonwovens primarily composed of fibers less than 100 mm in diameter. Long-fiber nonwovens are preferred because they provide superior strength in artificial leather. On the other hand, short-fiber nonwovens increase the number of fibers oriented in the thickness direction of the artificial leather compared to long-fiber nonwovens, resulting in a denser surface when raised.

[0062] When using a short-fiber nonwoven fabric, the ultrafine fibers preferably have a fiber length of 25 mm to 90 mm. By setting the fiber length to preferably 90 mm or less, more preferably 80 mm or less, and even more preferably 70 mm or less, good quality and feel are achieved. On the other hand, by setting the fiber length to preferably 25 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more, artificial leather with excellent abrasion resistance can be produced.

[0063] The basis weight of the nonwoven fabric constituting the artificial leather of the present invention is measured according to "6.2 Mass per unit area (International Organization for Standardization, ISO) method" of Japanese Industrial Standard (JIS) L1913:2010 "General nonwoven fabric test methods" and is preferably 50 g / m 2 Above 400g / m 2 By setting the unit area weight of the nonwoven fabric to preferably 50 g / m 2 More than 80 g / m 2 On the other hand, by setting the weight to preferably 400 g / m 2 Below, more preferably 300g / m 2 The following can produce an artificial leather with excellent formability and softness.

[0064] In order to improve the strength or shape stability of the artificial leather of the present invention, it is preferable to laminate a woven fabric inside or on one side of the nonwoven fabric and entangle the woven fabric to achieve integration.

[0065] As the type of fiber constituting the fabric used when the fabric is intertwined and integrated, it is preferred to use filament yarn, spun yarn, mixed composite yarn of filament yarn and spun yarn, etc. From the perspective of durability, especially mechanical strength, it is more preferred to use multifilament containing polyester resin or polyamide resin.

[0066] Furthermore, from the viewpoint of mechanical strength and the like, it is preferred that the fibers constituting the woven fabric do not contain a black pigment or a colored fine-particle oxide pigment.

[0067] By setting the average single fiber diameter of the fibers constituting the fabric to preferably 50 μm or less, more preferably 15 μm or less, and even more preferably 13 μm or less, not only can an artificial leather with excellent softness be obtained, but even when the fibers of the fabric are exposed on the surface of the artificial leather, the color difference from the pigmented ultrafine fibers after dyeing is small, thereby preventing the uniformity of the surface color. Furthermore, by setting the average single fiber diameter to preferably 1 μm or more, more preferably 8 μm or more, and even more preferably 9 μm or more, the morphological stability of the resulting artificial leather product is improved.

[0068] In the present invention, the average single fiber diameter of the fibers constituting the fabric is set as the following average single fiber diameter: by taking a scanning electron microscope (SEM, such as "VHX-D500 / D510" or "VE-7800" manufactured by KEYENCE Co., Ltd.) photograph of the cross-section of artificial leather, 10 fibers constituting the fabric are randomly selected, the single fiber diameters of the fibers are measured, and the arithmetic mean of the 10 fibers is calculated, and the result is rounded off to the second decimal place.

[0069] When the fibers constituting the woven fabric are multifilaments, the total fineness of the multifilaments is measured using "8.3 Fineness" "8.3.1 Normal fineness b) Method B (Simplified Method)" of JIS L1013:2010 "Testing Methods for Chemical Filament Yarns" and is preferably 30 dtex or more and 170 dtex or less.

[0070] By setting the total fineness of the yarns constituting the fabric to preferably 170 dtex or less, an artificial leather with excellent softness can be obtained. On the other hand, setting the total fineness to preferably 30 dtex or greater is preferred, as this not only improves the morphological stability of the artificial leather product but also reduces the exposure of the fibers constituting the fabric to the surface of the artificial leather when the nonwoven fabric and the fabric are intertwined and integrated by needle punching or the like. In this case, the total fineness of the warp and weft multifilament yarns is preferably the same.

[0071] Furthermore, the twist count of the yarns constituting the fabric is preferably set to 1000 T / m or more and 4000 T / m or less. By setting the twist count to preferably 4000 T / m or less, more preferably 3500 T / m or less, and further preferably 3000 T / m or less, an artificial leather having excellent softness can be obtained. By setting the twist count to preferably 1000 T / m or more, more preferably 1500 T / m or more, and further preferably 2000 T / m or more, damage to the fibers constituting the fabric can be prevented when the nonwoven fabric and the fabric are intertwined and integrated by needle punching, etc., and the mechanical strength of the artificial leather is excellent, which is preferred.

[0072] [Polymer elastomer]

[0073] As the polymer elastic body used in the artificial leather of the present invention, polyurethane, polyurea, polyurethane-polyurea elastomer, polyacrylic acid, acrylonitrile-butadiene elastomer, styrene-butadiene elastomer, etc. can be used. However, polyurethane is preferably used from the viewpoint of flexibility and cushioning properties.

[0074] In addition, the polymer elastomer may also include polyester, polyamide, and polyolefin elastomer resins, acrylic resins, and ethylene vinyl acetate resins. The elastic polymer may be soluble in an organic solvent or dispersed in water; either type may be used.

[0075] The polyurethane used in the present invention may be either an organic solvent-based polyurethane used in a state of being dissolved in an organic solvent or a water-dispersible polyurethane used in a state of being dispersed in water. Furthermore, the polyurethane used in the present invention may preferably be a polyurethane obtained by reacting a polymer diol with an organic diisocyanate and a chain extender.

[0076] As the polymer diol, for example, polycarbonate diol, polyester diol, polyether diol, silicone diol, and fluorine diol can be used, and copolymers of these can also be used. Among them, the use of polycarbonate diol is a preferred form from the viewpoint of hydrolysis resistance and wear resistance.

[0077] The polycarbonate diol can be produced by, for example, a transesterification reaction between an alkane diol and a carbonate, or a reaction between phosgene or a chloroformate and an alkane diol.

[0078] Examples of the alkane diol include linear alkane diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol; branched alkane diols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanediol; aromatic diols such as bisphenol A; glycerol, trimethylolpropane; and pentaerythritol. In the present invention, polycarbonate diols obtained from individual alkane diols and copolymerized polycarbonate diols obtained from two or more alkane diols may also be used.

[0079] Examples of the polyester diol include polyester diols obtained by condensing various low-molecular-weight polyols with polybasic acids.

[0080] As the low molecular weight polyol, for example, one or more selected from ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, and cyclohexane-1,4-dimethanol can be used.

[0081] Furthermore, adducts obtained by adding various alkylene oxides to bisphenol A can also be used.

[0082] Examples of the polybasic acid include one or more selected from succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydroisophthalic acid.

[0083] Examples of the polyether diol used in the present invention include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymeric glycols obtained by combining these.

[0084] When the molecular weight of the polyurethane elastomer is constant, the number average molecular weight of the polymer diol is preferably in the range of 500 to 4000. By setting the number average molecular weight to preferably 500 or more, more preferably 1500 or more, the artificial leather can be prevented from becoming hard. In addition, by setting the number average molecular weight to preferably 4000 or less, more preferably 3000 or less, the strength of the polyurethane can be maintained.

[0085] Examples of the organic diisocyanate used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylene diisocyanate, and aromatic diisocyanates such as diphenylmethane diisocyanate and toluene diisocyanate. These can also be used in combination.

[0086] As the chain extender, preferably used are amine-based chain extenders such as ethylenediamine and methylenedianiline, or diol-based chain extenders such as ethylene glycol. In addition, polyamines obtained by reacting polyisocyanate with water can also be used as the chain extender.

[0087] To improve water resistance, abrasion resistance, and hydrolysis resistance, the polyurethane used in the present invention may be used in combination with a crosslinking agent. The crosslinking agent may be an external crosslinking agent added as a third component to the polyurethane, or an internal crosslinking agent that preliminarily introduces reaction sites that form a crosslinking structure into the polyurethane molecular structure. Internal crosslinking agents are preferred because they allow for more uniform formation of crosslinking sites within the polyurethane molecular structure, thereby reducing the loss of flexibility.

[0088] As the cross-linking agent, a compound having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, or the like can be used.

[0089] Furthermore, the polymeric elastomer may optionally contain pigments such as carbon black, dyes, antioxidants, antioxidants, light stabilizers, antistatic agents, dispersants, softeners, setting regulators, flame retardants, antibacterial agents, and deodorants. In particular, the polymeric elastomer of the present invention preferably contains a black pigment.

[0090] Generally speaking, the content of a polymeric elastomer in artificial leather can be appropriately adjusted depending on the type of polymeric elastomer used, the method for producing the polymeric elastomer, and its feel or physical properties. However, in the present invention, the content of the polymeric elastomer is preferably set to 10% by mass or more and 60% by mass or less relative to the mass of the fiber-wound body. By setting the content of the polymeric elastomer to preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, the bonds formed between fibers by the polymeric elastomer can be strengthened, thereby improving the wear resistance of the artificial leather. On the other hand, by setting the content of the polymeric elastomer to preferably 60% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, the artificial leather can be made more flexible.

[0091] [Artificial leather]

[0092] The artificial leather of the present invention comprises the aforementioned fiber-entangled body and the aforementioned polymeric elastomer. Furthermore, at least one surface of the artificial leather is a designed surface having at least a raised portion and a fused portion. The designed surface herein refers to the surface located outermost in the finished product. Furthermore, the raised portion refers to a portion of the surface having raised pile containing ultrafine fibers, and the fused portion refers to a portion where the thermoplastic resin primarily constituting the ultrafine fibers is fused together into a mass, i.e., a portion where a fused product exists.

[0093] In terms of design effects, the raised portion preferably has a raised length and directional flexibility sufficient to leave a mark due to a change in the direction of the raised pile when drawn with a finger, so-called finger marks.

[0094] More specifically, the pile length of the surface pile portion is preferably from 200 μm to 500 μm, more preferably from 250 μm to 450 μm. By setting the pile length preferably to 200 μm or more, the surface pile is coated with the polymeric elastomer, which prevents exposure of the polymeric elastomer from the surface of the artificial leather, thereby achieving an artificial leather with uniform color development. Furthermore, when the fiber-wound body constituting the artificial leather is formed by intertwining and integrating a nonwoven fabric and a woven fabric, setting the pile length of the surface pile portion within the above range is preferred because it allows sufficient coverage of the fibers of the woven fabric located near the surface of the artificial leather. On the other hand, by setting the pile length preferably to 500 μm or less, an artificial leather with excellent design effects and wear resistance can be achieved.

[0095] In the present invention, the nap length of the napped portion on the surface of the artificial leather is calculated by the following method.

[0096] (1) The raised nap portion of the surface of the artificial leather is inverted using a lint brush or the like, and a thin slice having a thickness of 1 mm is prepared in the cross-sectional direction of a surface perpendicular to the longitudinal direction of the artificial leather.

[0097] (2) Observe the cross section of the napped portion of the surface of the artificial leather at 90x magnification using a scanning electron microscope (SEM, such as "VHX-D500 / D510" or "VE-7800" manufactured by KEYENCE Corporation).

[0098] (3) In the captured SEM image, the height of the layer consisting only of ultrafine fibers was measured at ten locations at intervals of 200 μm along the width direction of the cross section of the napped portion of the surface of the artificial leather.

[0099] (4) The average value (arithmetic mean) of the heights of the layer containing only ultrafine fibers at the ten measured locations was calculated.

[0100] In the artificial leather of the present invention, the content of the thermoplastic resin in the fused portion is 99 parts by mass or more and 101 parts by mass or less, based on 100 parts by mass of the thermoplastic resin in the raised portion. Thus, by eliminating the difference in content between the raised portion and the fused portion, the mechanical properties of the artificial leather are improved.

[0101] In the present invention, the ratio of the content of the thermoplastic resin in the fusion portion to the content of the thermoplastic resin in the napped portion of the artificial leather is calculated by the following method.

[0102] (1) For the napped part, use a nuclear magnetic resonance (NMR) device to measure 1 The content ratio of the thermoplastic resin as the main component was calculated from the peak area obtained by H-NMR.

[0103] (2) For the fused portion, the content ratio of the same thermoplastic resin as the main component of the raised portion is calculated in the same manner as in (1).

[0104] (3) The content ratio of the thermoplastic resin in the fusion portion is calculated when the content ratio of the thermoplastic resin in the napped portion is 100 parts by mass.

[0105] Furthermore, in the artificial leather of the present invention, the difference between the thickness of the pile portion and the thickness of the fused portion is 0.05 mm or more and 0.20 mm or less. By setting the difference between the thickness of the pile portion and the thickness of the fused portion to 0.05 mm or more, preferably 0.07 mm or more, and more preferably 0.10 mm or more, an artificial leather with sufficient pattern visibility and excellent design can be produced. By setting the difference between the thickness of the pile portion and the thickness of the fused portion to 0.20 mm or less, preferably 0.19 mm or less, and more preferably 0.18 mm or less, a decrease in softness caused by excessive fusion of ultrafine fibers or thermal degradation of the polymer elastomer can be prevented, resulting in an excellent hand feel.

[0106] The difference between the thickness of the raised portion and the thickness of the fused portion is a value obtained by observing a cross section perpendicular to the thickness direction of the artificial leather at a magnification of 200 times using a scanning electron microscope (SEM, such as "VHX-D500 / D510" or "VE-7800" manufactured by KEYENCE Co., Ltd.), and measuring the height difference between the raised portion and the fused portion as the value obtained by the above method. Figure 1 The distance AB between the highest point A and the lowest point B shown in the example is rounded off for the average value of the randomly selected convex portion 20. Here, the lowest point B is selected as the lower one of the positions where the slope of the inclination of the two end portions disappears (0°) in the convex portion.

[0107] The artificial leather of the present invention preferably has a pile portion thickness of 0.2 mm to 2.8 mm, as measured by "6.1 Thickness (ISO Method)" in JIS L1913:2010, "Test Methods for General Nonwoven Fabrics," Method 6.1.1A. By setting the thickness of the artificial leather to 0.2 mm or greater, more preferably 0.3 mm or greater, and even more preferably 0.4 mm or greater, the leather not only exhibits excellent processability during production but also has a substantial feel and excellent hand. On the other hand, by setting the thickness to 2.8 mm or less, more preferably 2.7 mm or less, and even more preferably 2.6 mm or less, the leather can be made into an artificial leather with excellent formability and flexibility.

[0108] The important thing about the artificial leather of the present invention is the color difference ΔE* between the raised portion and the fused portion. ab and hue difference ΔH* ab The following equations (1) and (2) are satisfied respectively.

[0109] ΔE* ab ≧5…(1)

[0110] 0≦ΔH* ab ≦1.0…(2)

[0111] By dividing ΔE* ab Setting ΔH* to 5 or more, preferably 5.5 or more, and more preferably 6 or more, can provide a pattern with sufficient visibility. ab By setting the value to 0 or more and 1.0 or less, preferably 0 or more and 0.9 or less, and more preferably 0.8 or less, sufficient visibility can be ensured while imparting a harmonious and elegant design to the pattern without being glaring.

[0112] Furthermore, the color difference ΔE* between the raised part and the fused part ab and hue difference ΔH* ab The measurement was performed as follows.

[0113] (1) Using a spectrophotometer (e.g., "CM-2600d" manufactured by Konica Minolta Japan Co., Ltd.), measure five random locations on the napped portion of the surface, and use the average values ​​as the average lightness L*, average hue a*, and average hue b* of the napped portion.

[0114] (2) Similarly, five locations on the fused portion of the surface were measured, and the average values ​​thereof were taken as the average lightness L*, average hue a*, and average hue b* of the fused portion.

[0115] (3) Based on the obtained average brightness L*, average hue a*, and average hue b*, the color difference ΔE* between the raised portion and the fused portion is calculated using the following formula: ab and hue difference ΔH* ab.

[0116] ΔL*=(average brightness L* of the raised portion)-(average brightness L* of the fused portion)

[0117] Δa*=(average brightness a* of the raised portion)-(average brightness a* of the fused portion)

[0118] Δb*=(average brightness b* of the raised portion)-(average brightness b* of the fused portion)

[0119] ΔE* ab ={(ΔL*) 2 +(Δa*) 2 +(Δb*) 2} 1 / 2

[0120] ΔC*={(Δa*) 2 +(Δb*) 2} 1 / 2

[0121] ΔH* ab ={(Δa*) 2 +(Δb*) 2 -(ΔC*) 2} 1 / 2

[0122] Here, when the size of the fusion portion is less than 3 mm in diameter, a plurality of fusion portions are cut out to form a state in which they are arranged without gaps, and the measurement can be performed using the same method as above.

[0123] It is also important that the artificial leather of the present invention satisfies the following formula (3).

[0124] 2D≦φ≦150…(3)

[0125] Here, D is the average single fiber diameter (μm) of the ultrafine fibers, and φ is the size (μm) of the fusion. By setting the size φ (μm) of the fusion to 2D or greater (2D ≤ v, the same applies hereinafter), preferably 2.5D or greater (2.5D ≤ φ), and more preferably 3D or greater (3D ≤ φ), an artificial leather with a sufficiently visible pattern can be produced. On the other hand, by setting the size of the fusion to 150 μm or less (φ ≤ 150, the same applies hereinafter), preferably 140 μm or less (φ ≤ 140), and more preferably 130 μm or less (φ ≤ 130), clear pattern boundaries and fine patterns can be expressed, resulting in excellent design.

[0126] In the present invention, the fusion product of the fusion portion of the artificial leather is calculated by the following method.

[0127] (1) Observe the fusion portion of the artificial leather surface at 300 times magnification using a scanning electron microscope (SEM, such as "VHX-D500 / D510" or "VE-7800" manufactured by KEYENCE Corporation).

[0128] (2) Figure 2 As shown in the example, the maximum diameter of the circle that can be included in the fusion is measured (5 μm scale). Figure 2 , then a circle with a diameter of 150 μm may be included at location C, a circle with a diameter of 140 μm may be included at location D, a circle with a diameter of 170 μm may be included at location E, and a circle with a diameter of 200 μm may be included at location F.

[0129] (3) For the fusion sites of ten randomly selected sites, the maximum diameter of the circle that can be included in the fusion was measured, and the maximum value was taken as the fusion size.

[0130] The artificial leather of the present invention preferably has a rubbing fastness of the napped portion measured using "9.1 Crockmeter Type I (Crock Meter Method)" of JIS L0849:2013 "Test Methods for Color Fastness to Rubbing" and a light fastness measured using "7.2 Exposure Method a) First Exposure Method" of JIS L0843:2006 "Test Methods for Color Fastness to Xenon Arc Light" of Grade 4 or higher. A rubbing fastness and light fastness of Grade 4 or higher can prevent fading and staining of clothing during actual use.

[0131] Furthermore, in an abrasion resistance test measured according to "8.19.5E Method (Martindale Method)" in "8.19 Abrasion Strength and Friction Discoloration" of JIS L1096:2010 "Test Methods for Textile and Knitted Fabrics," the artificial leather of the present invention exhibits a mass loss of preferably 10 mg or less, more preferably 8 mg or less, and even more preferably 6 mg or less, after 20,000 abrasions with a pressing load of 12.0 kPa. A mass loss of 10 mg or less can prevent contamination caused by lint shedding during actual use.

[0132] The artificial leather of the present invention preferably has a tensile strength of 20 N / cm to 200 N / cm in any measuring direction as measured according to "6.3.1 Tensile Strength and Elongation (ISO Method)" of JIS L1913:2010 "General Nonwoven Fabric Test Methods".

[0133] If the tensile strength is preferably 20 N / cm or more, more preferably 30 N / cm or more, and further preferably 40 N / cm or more, the artificial leather can be made excellent in morphological stability and durability. If the tensile strength is preferably 200 N / cm or less, more preferably 180 N / cm or less, and further preferably 150 N / cm or less, the artificial leather can be made even more excellent in formability.

[0134] [Manufacturing method of artificial leather]

[0135] The artificial leather of the present invention is preferably produced by including the following steps (1) to (5).

[0136] Step (1): a step of producing an ultrafine fiber-forming fiber having an island-in-sea composite structure, wherein the island-in-sea composite structure comprises an island portion containing a thermoplastic resin and a sea portion containing a readily soluble polymer.

[0137] Step (2): a step of manufacturing a fibrous base material having ultrafine fiber-forming fibers as a main component

[0138] Step (3): A step of developing ultrafine fibers having an average single fiber diameter of 1 μm or more and 10 μm or less from a fibrous substrate mainly composed of ultrafine fiber-developing fibers

[0139] Step (4): A step of imparting a polymer elastic body to a fibrous substrate having ultrafine fibers or ultrafine fiber-forming fibers as a main component

[0140] Step (5): Step of forming a design surface on at least one surface

[0141] Hereinafter, each step will be described in detail.

[0142] <Process for producing ultrafine fiber-forming fibers>

[0143] In this step, an ultrafine fiber-developing fiber having a sea-island type composite structure is produced, wherein the island portion is formed by a thermoplastic resin and the sea portion is formed by a readily soluble polymer.

[0144] As the ultrafine fiber-forming fiber, the following island-in-the-sea composite fiber is used: thermoplastic resins with different solvent solubilities serve as a sea portion (easily soluble polymer) and an island portion (poorly soluble polymer). The sea portion is dissolved and removed using a solvent, thereby leaving the island portion as the ultrafine fibers. By using an island-in-the-sea composite fiber, appropriate spaces can be created between the island portions, i.e., between the ultrafine fibers within the fiber bundle, after the sea portion is removed. This is preferable from the perspective of the feel and surface quality of artificial leather.

[0145] As a method for spinning ultrafine fiber-developing fibers having an island-in-sea composite structure, from the perspective of obtaining ultrafine fibers with uniform single fiber fineness, it is preferred to use an island-in-sea composite die to arrange the sea portion and the island portion and spin a polymer array.

[0146] As the sea portion of the island-in-sea composite fiber, polyethylene, polypropylene, polystyrene, copolyesters obtained by copolymerizing sodium sulfoisophthalic acid or polyethylene glycol, and polylactic acid can be used. From the viewpoint of spinning properties and easy dissolution, polystyrene or copolyesters are preferably used.

[0147] In the method for producing artificial leather of the present invention, when using sea-island composite fibers, it is preferred that the fibers have an island portion strength of 2.5 cN / dtex or greater. By having an island portion strength of 2.5 cN / dtex or greater, more preferably 2.8 cN / dtex or greater, and even more preferably 3.0 cN / dtex or greater, the abrasion resistance of the artificial leather can be improved, and a decrease in friction fastness associated with fiber shedding can be suppressed.

[0148] In the present invention, the strength of the island portion of the sea-island type composite fiber is calculated by the following method.

[0149] (1) Bundle 10 island-in-the-sea composite fibers with a length of 20 cm.

[0150] (2) After dissolving and removing the sea part from the sample of (1), the sample was air-dried.

[0151] (3) Using "8.5 Tensile Strength and Elongation" of "8.5.1 Standard Time Test" in JIS L1013:2010 "Test Methods for Chemical Filament Yarns", 10 tests (N=10) were conducted under the conditions of a grip length of 5 cm, a tensile speed of 5 cm / min, and a load of 2 N.

[0152] (4) The arithmetic mean value (cN / dtex) of the test results obtained in (3) was rounded off to the second decimal place and was used as the strength of the island portion of the sea-island type composite fiber.

[0153] <Process for manufacturing fibrous substrate>

[0154] In this process, the spun ultrafine fiber-forming fibers are opened and then formed into a fiber web using a crosslapper or the like, and then entangled to obtain a nonwoven fabric. The fiber web can be entangled to obtain a nonwoven fabric by needle punching or water jet punching.

[0155] As mentioned above, the nonwoven fabric may be either short-fiber or long-fiber. However, short-fiber nonwoven fabrics have more fibers in the thickness direction of the artificial leather than long-fiber nonwoven fabrics, and thus a dense feel can be obtained on the surface of the artificial leather during raising.

[0156] When a staple nonwoven fabric is produced as a nonwoven fabric, the obtained ultrafine fiber-developing fibers are preferably crimped, cut to a predetermined length to obtain raw fibers, and then opened, laminated, and intertwined to obtain a staple nonwoven fabric. The crimping or cutting process can be performed using known methods.

[0157] Furthermore, when the artificial leather comprises a fabric, the obtained nonwoven fabric is laminated with the fabric and then intertwined and integrated. The intertwined integration of the nonwoven fabric and the fabric can be achieved by laminating the fabric on one or both sides of the nonwoven fabric, or by sandwiching the fabric between multiple nonwoven fabric webs and then entangled with the fibers of the nonwoven fabric and the fabric by needle punching or hydroentanglement.

[0158] The apparent density of the nonwoven fabric containing ultrafine fiber-forming fibers after needle punching or hydroentanglement is preferably 0.15 g / cm 3 Above and 0.45g / cm 3 By setting the apparent density to preferably 0.15 g / cm 3 The above results in sufficient morphological stability and dimensional stability of the artificial leather. 3 Thereby, a sufficient space for providing the polymer elastic body can be maintained.

[0159] In order to increase the density of the fibers, it is also preferable to subject the nonwoven fabric to a heat shrinkage treatment using warm water or steam.

[0160] Next, the water-soluble resin may be added to the nonwoven fabric by impregnating the nonwoven fabric with an aqueous solution of the water-soluble resin and drying the impregnated nonwoven fabric.

[0161] <Process for developing ultra-fine fibers>

[0162] In this step, the obtained fibrous base material is treated with a solvent to develop ultrafine fibers having an average single fiber diameter of 1 μm to 10 μm.

[0163] The ultrafine fibers can be visualized by immersing a nonwoven fabric containing the island-in-the-sea composite fibers in a solvent to dissolve and remove the sea portion of the island-in-the-sea composite fibers.

[0164] When the ultrafine fiber-developing fiber is a sea-island composite fiber, an organic solvent such as toluene or trichloroethylene can be used as a solvent to dissolve and remove the hemisphere, if the hemisphere is polyethylene, polypropylene, or polystyrene. Alternatively, an aqueous alkaline solution such as sodium hydroxide can be used if the hemisphere is copolyester or polylactic acid. Furthermore, a hydrothermal solution can be used if the hemisphere is a water-soluble thermoplastic polyvinyl alcohol-based resin.

[0165] <Process of Imparting the Polymer Elastomer>

[0166] In this step, a solution of a polymeric elastomer is impregnated into a fibrous substrate primarily composed of ultrafine fibers or ultrafine fiber-developing fibers and then solidified to impart the polymeric elastomer. Methods for attaching the polymeric elastomer to a nonwoven fabric include impregnating the nonwoven fabric (fiber-entangled body) with a solution of the polymeric elastomer and then performing wet coagulation or dry coagulation. The appropriate method is selected depending on the type of polymeric elastomer used.

[0167] As a solvent used when providing polyurethane as a polymeric elastic body, N,N'-dimethylformamide, dimethyl sulfoxide, etc. can be preferably used. Alternatively, a water-dispersible polyurethane liquid obtained by dispersing polyurethane in water as an emulsion can be used.

[0168] The polymeric elastic body may be applied to the fibrous base material before or after ultrafine fibers are developed from the ultrafine fiber-developing fibers.

[0169] <Process of cutting the sheet in half and grinding it>

[0170] From the viewpoint of production efficiency, it is also preferable that the sheet-like article to which the polymer elastic body is applied, obtained after completing the above steps, is cut in half in the thickness direction to form two sheets.

[0171] Furthermore, the surface of the sheet-like article to which the polymer elastomer is applied, or the surface of the sheet-like article after being cut in half, may be subjected to a napping treatment. The napping treatment may be applied by grinding with sandpaper or a roll sander. The napping treatment may be applied to only one side of the sheet-like article, or to both sides.

[0172] In the case of applying a napping treatment, a lubricant such as a silicone emulsion may be applied to the surface of the sheet before the napping treatment. In addition, by applying an antistatic agent before the napping treatment, grinding powder generated from the sheet by grinding is less likely to accumulate on the sandpaper.

[0173] <Dyeing process of sheet materials>

[0174] The sheet is also preferably dyed. Examples of such dyeing include: immersion dyeing using a jigger dyeing machine or a jet dyeing machine, thermosol dyeing using a continuous dyeing machine, or dyeing of the napped surface using roller printing, screen printing, inkjet printing, sublimation printing, and vacuum sublimation printing. Among these, a jet dyeing machine is preferred for achieving a soft feel and excellent quality and taste.

[0175] <Step of forming a designed surface on at least one surface of a sheet-like object>

[0176] In this step, a design surface is formed on at least one surface of the sheet obtained in the previous steps. Thus, an arbitrary pattern is imparted to at least one surface of the sheet, thereby obtaining the artificial leather of the present invention.

[0177] In the method for producing artificial leather of the present invention, laser irradiation is preferably used for forming the design surface, i.e., for imparting the pattern. A CO2 laser having a wavelength in the infrared region is more preferred. Furthermore, a pulsed laser or a CW laser (continuous wave laser) can also be preferably used as the laser oscillator.

[0178] The average power of the laser beam is preferably 70W to 300W, and the focal diameter is preferably 0.5mm or less. By setting the average power and focal diameter to these ranges, the energy density calculated from the power and focal diameter can be set to 70 / (π×0.25×0.25) to 300 / (π×0.25×0.25)≒350(W / mm 2 )~1500(W / mm 2 By setting the energy density within these ranges, the ultrafine fibers containing the thermoplastic resin can be heated sufficiently to the temperature required for melting, and overheating can be prevented to suppress thermal degradation, so it is preferred. A more preferred range is an energy density of 500 (W / mm 2 )~1000(W / mm 2 ). In addition, from the perspective of productivity, the feed speed of the laser beam is preferably 5 m / min or more.

[0179] The artificial leather of the present invention obtained by the above-exemplified production method has a natural leather-like soft touch and excellent design properties, and is also excellent in abrasion resistance, and can be widely used in applications ranging from furniture, chairs, and vehicle interior materials to clothing.

[0180] Example

[0181] Next, the present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

[0182] [Measurement method and processing method for evaluation]

[0183] (1) Average single fiber diameter of ultrafine fibers (μm):

[0184] In the measurement of the average single fiber diameter of the ultrafine fibers, observation was performed using a scanning electron microscope "VHX-D500 / D510" manufactured by KEYENCE Corporation, and the average single fiber diameter was calculated.

[0185] (2) Thermoplastic resin content in the napped portion and the thermoplastic resin content in the fused portion (%):

[0186] The content of the thermoplastic resin in the napped portion and the content of the thermoplastic resin in the fused portion were measured using “JNM-A400” manufactured by JEOL Ltd., an NMR.

[0187] (3) The difference between the thickness of the pile part and the thickness of the fusion part (mm):

[0188] The cross section perpendicular to the thickness direction of the artificial leather was observed at a magnification of 100 times using a scanning electron microscope (SEM, "VHX-D500 / D510" manufactured by KEYENCE Co., Ltd.), and the height difference between the observed raised part and the fused part was measured. Figure 1 As an example, the distance AB between the highest point A and the lowest point B is evaluated as the average value of 20 randomly selected convex portions. The lowest point B is selected as the lower one of the positions where the slope of the inclination of the two end portions of the convex portion disappears (0°).

[0189] (4) Color difference ΔE* between the raised part and the fused part ab and hue difference ΔH* ab :

[0190] The spectrophotometer used was a "CM-2600d" manufactured by Konica Minolta Japan Co., Ltd., with an illuminant D of 65, a viewing angle of 10 degrees, and a measurement diameter of 3 mmφ. Measurements were performed in a reflective setting under optical conditions based on JIS Z8781-4:2013 "Colorimetry - Part 4: CIE 1976 L*a*b* color space."

[0191] (5) Fusion size (μm):

[0192] To measure the size of the fusion portion of the artificial leather, a scanning electron microscope "VHX-D500 / D510" manufactured by KEYENCE Corporation was used.

[0193] (6) Pile length of artificial leather (μm):

[0194] For the measurement of the nap length of the artificial leather, a scanning electron microscope "VHX-D500 / D510" manufactured by KEYENCE Corporation was used.

[0195] (7) Pattern visibility:

[0196] Ten healthy subjects visually inspected the artificial leather for three seconds from a distance of 2 meters. If eight or more people could visually identify the pattern (identifiable as a polka dot pattern), the result was graded as (A); if 5-7 people could visually identify the pattern, the result was graded as (B); if 3-4 people could visually identify the pattern, the result was graded as (C); and if less than two people could visually identify the pattern, the result was graded as (D). Grades A and B were considered acceptable.

[0197] (8) Vividness of the pattern:

[0198] Ten healthy subjects visually inspected and evaluated the clarity of the pattern boundary. Artificial leather rated as clear by at least eight subjects (smooth and realistic pattern boundaries) was assigned an "A" rating, those rated as clear by 5-7 subjects were assigned a "B" rating, those rated as clear by 3-4 subjects were assigned a "C" rating, and those rated as clear by 2 or fewer subjects were assigned a "D" rating. Results of A and B were considered acceptable.

[0199] (9) Feel:

[0200] Ten panelists evaluated the feel of the artificial leather. Those rated good (excellent softness) by eight or more panelists were assigned an "A" rating, those rated good by five to seven panelists were assigned a "B" rating, those rated good by three to four panelists were assigned a "C" rating, and those rated good by two or fewer panelists were assigned a "D" rating. A and B ratings were considered acceptable.

[0201] [Example 1]

[0202] <Process of producing raw cotton>

[0203] Ultrafine fiber-developing fibers having a sea-island type composite structure including island components and sea components were melt-spun under the following conditions.

[0204] Island component: The island component is a mixture of the following components P1 and P2 at a mass ratio of 95:5

[0205] P1 Polyethylene terephthalate A with an intrinsic viscosity (IV value) of 0.73

[0206] P2 is a masterbatch containing 20% ​​by mass of carbon black (average particle size: 0.02 μm, coefficient of variation (CV): 20%) as a black pigment (a1) in the polyethylene terephthalate A based on the mass of the masterbatch.

[0207] Sea component: Polystyrene with a melt flow rate (MFR) of 65 g / 10 min

[0208] Die: Sea-island composite die with 16 islands / hole

[0209] Spinning temperature: 285℃

[0210] Island / Sea Quality Ratio: 90 / 10

[0211] ·Dispensing volume: 1.8g / (minute / hole)

[0212] Spinning speed: 1100m / min

[0213] The yarn was then stretched to 3.0 times its original length in a spinning oil bath at 90°C. After crimping using a press-type crimper, it was cut into 51 mm lengths to obtain raw cotton for island-in-the-sea composite fibers with a single fiber fineness of 5.9 dtex. The ultrafine fibers obtained from these island-in-the-sea composite fibers had an average staple fiber diameter of 5.5 μm and a strength of 3.4 cN / dtex. The average particle size of the carbon black in the ultrafine fibers was 0.07 μm, and the coefficient of variation (CV) of the particle size was 30%.

[0214] <Process for manufacturing fibrous substrate>

[0215] First, the raw cotton obtained as described above is carded and cross-lapped to form a laminated web. 2 The needle punching process was carried out with the number of needles to obtain a unit area weight of 510g / m 2 And the thickness of the non-woven fabric is 2.1mm.

[0216] <Process for developing ultra-fine fibers>

[0217] The nonwoven fabric obtained as above is subjected to shrinkage treatment using a hot liquid at 96°C. Thereafter, a polyvinyl alcohol (PVA) aqueous solution prepared to a concentration of 12% by mass and a saponification degree of 88% is impregnated into the nonwoven fabric subjected to shrinkage treatment using a hot liquid. Furthermore, it is squeezed using a roller, and the PVA is migrated using hot air at a temperature of 120°C while being dried for 10 minutes, thereby obtaining a PVA-containing sheet having a PVA mass of 25% relative to the mass of the sheet substrate. The PVA-containing sheet obtained in the above manner is immersed in trichloroethylene, and the mangling and compression using a mangle are performed ten times. Thus, the dissolution and removal of the sea portion and the compression treatment of the PVA-containing sheet are performed, thereby obtaining a PVA-containing sheet in which ultrafine fiber bundles endowed with PVA are entangled.

[0218] <Process of Imparting the Polymer Elastomer>

[0219] The PVA-coated sheet obtained above was impregnated with a dimethylformamide (DMF) solution of polyurethane containing carbon black (average primary particle size 0.02 μm, coefficient of variation CV: 20%) as a black pigment (b) and containing polyurethane at a solids concentration of 13%. The kelp-free PVA sheet immersed in the DMF solution of polyurethane was then squeezed with a roller. The sheet was then immersed in a 30% by mass aqueous DMF solution to solidify the polyurethane. The PVA and DMF were then removed using a hot solution and impregnated with a silicone oil emulsion adjusted to a concentration of 1% by mass. The silicone lubricant was applied to the sheet at a total weight of 0.4% by mass relative to the combined weight of the fibrous substrate and the polyurethane, and then dried with hot air at 110°C for 10 minutes. This produced a polyurethane-coated sheet with a thickness of 1.7 mm and a polyurethane weight of 29% by mass relative to the weight of the fibrous substrate.

[0220] <Half-cutting and raising process>

[0221] The polyurethane sheet obtained above was cut in half so that the thickness was 1 / 2, and the surface of the cut surface was ground by 0.3 mm using 180-grade circular sandpaper to obtain a napped sheet with a thickness of 0.6 mm.

[0222] <Dyeing and finishing process>

[0223] The napped sheet obtained as described above was dyed using a jet dyeing machine. A recipe was used to adjust the L* value of the dyed sheet to 22 using a black dye at 120°C. The sheet was then dried at 100°C for 7 minutes to obtain ultrafine fibers with an average single fiber diameter of 5.5 μm and a weight per unit area of ​​255 g / m².2 , a dyed sheet with a thickness of 0.7 mm and a pile length of 330 μm.

[0224] <Pattern-adding Process>

[0225] To the artificial leather that obtains as described, use carbon dioxide laser (pulse oscillation type) irradiator of wavelength 10.6 μ m, give the pattern of polka dot pattern (a regular triangle of 5mm on one side is configured to zigzag lattice shape with the interval of 10mm).At this moment, the feed speed with the length direction of dyeing sheet is that the moving speed 9m / min of the laser processing point on the width direction of 11cm / min, pulse frequency 50kHz, average power 110W, focusing diameter 0.5mm, dyeing sheet processes, obtains artificial leather.The artificial leather that obtains has excellent pattern recognition and distinctness, feel.Result is shown in Table 1.

[0226] [Example 2]

[0227] A patterned artificial leather was obtained in the same manner as in Example 1, except that the patterning step was performed at an average power of 150 W. The obtained artificial leather had excellent pattern visibility, clarity, and hand feel. The results are shown in Table 1.

[0228] [Example 3]

[0229] In the process of producing the raw cotton, only P1 was used as the island component, and a patterned artificial leather was obtained in the same manner as in Example 2. The obtained artificial leather had excellent pattern visibility, clarity, and hand feel. The results are shown in Table 1.

[0230] [Example 4]

[0231] Artificial leather was produced in the same manner as in Example 2, except that the island / sea mass ratio in the raw cotton production step was set to 80 / 20, the discharge rate was set to 1.2 g / (min / hole), the stretching ratio was set to 2.7 times, and the average short fiber diameter of the ultrafine fibers was set to 4.4 μm. The resulting artificial leather had excellent pattern visibility, clarity, and hand feel. The results are shown in Table 1.

[0232] [Comparative Example 1]

[0233] In the patterning step, a printing paste of the following composition was printed using a screen printer, dried, and then irradiated with near-infrared light having a dominant wavelength of 750 μm at a cloth speed of 4 m / min. Artificial leather was obtained in the same manner as in Example 3, except that the printing paste was irradiated with near-infrared light having a dominant wavelength of 750 μm at a cloth speed of 4 m / min. The obtained artificial leather was found to have a poor feel due to the infrared irradiation, heating and curing of not only the printed areas but also the black pigment-containing elastomer. The results are shown in Table 1.

[0234] <Printing paste composition>

[0235] 35.5 parts by mass of original paste (guar gum solid content 15%)

[0236] · Dyeing agent (S-10 from Nippon Chemical Products Co., Ltd.) 30.0 parts by mass

[0237] Carrier (Teryl Carrier FPL manufactured by Meisei Chemical Co., Ltd.) 5.0 parts by mass

[0238] 1.5 parts by mass of graphite powder

[0239] Disperse dye (Japan Chemical Products Co., Ltd.) 8.0 parts by mass

[0240] 20.0 parts by mass of water.

[0241] [Comparative Example 2]

[0242] Artificial leather was obtained in the same manner as in Example 2 except that the average power in the patterning step was set to 300 W. Perforations were observed in the fusion portion of the patterned artificial leather. The results are shown in Table 1.

[0243] [Comparative Example 3]

[0244] Artificial leather was obtained in the same manner as in Example 2 except that the average power in the patterning step was set to 190 W. The obtained artificial leather had poor pattern clarity and poor hand feel. The results are shown in Table 1.

[0245] [Comparative Example 4]

[0246] Artificial leather was obtained in the same manner as in Example 2 except that the average power in the patterning step was set to 60 W. The obtained artificial leather had poor visibility and clarity of the pattern. The results are shown in Table 1.

[0247] [Table 1]

[0248]

Claims

1. An artificial leather comprising a fiber winding body and a polymer elastic body, wherein the fiber winding body comprises a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 1 μm to 10 μm inclusive and containing a thermoplastic resin, and the polymer elastic body contains a black pigment, wherein: At least one surface of the artificial leather is a designed surface having at least a raised portion and a fused portion, the raised portion being a portion having raised pile containing ultrafine fibers on the surface, the fused portion being a portion where thermoplastic resin constituting the ultrafine fibers is fused into a block, the raised pile length of the raised portion being 200 μm or more and 500 μm or less, the content of the thermoplastic resin in the fused product of the fused portion being 99 parts by mass or more and 100 parts by mass when the content of the thermoplastic resin in the raised portion is 100 parts by mass, the difference between the thickness of the raised portion and the thickness of the fused portion being 0.05 mm or more and 0.19 mm or less, and the following formulas (1) to (3) are satisfied respectively. ΔE* ab ≧5···(1) 0≦ΔH* ab ≦1···(2) 2D≦φ≦150···(3) Where, ΔE* ab It is the International Illumination Commission LAB1976 L*a*b* color difference between the raised part and the fused part, ΔH* ab is the International Illumination Commission LAB1976 hue difference between the raised portion and the fusion portion, D is the average single fiber diameter of the ultrafine fiber, and its unit is μm, φ is the size of the fusion, and its unit is μm, wherein the size of the fusion is obtained by measuring the maximum diameter of a circle that can be contained in the fusion for the fusion portions of ten randomly selected locations, and taking the maximum value as the size of the fusion. 2 . The artificial leather according to claim 1 , wherein the ultrafine fibers further contain a black pigment in addition to the thermoplastic resin.

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