Artificial leather and artificial leather manufacturing method

Abstract

To provide an artificial leather that is dyed only with naturally derived dye and has washing fastness and light fastness.SOLUTION: An artificial leather consists of a fiber entangled body containing a nonwoven fiber formed of polyester fibers containing dye as a constituent, and elastomer. Ratio of the naturally derived dye in the dye is 98 mass% or more and 100 mass% or less. Washing fastness (discoloration) specified in AATCC-61 1-A method of the artificial leather is rank 3 or higher and light fastness specified in JIS L0842 is rank 3 or higher.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to artificial leather dyed with naturally occurring dyes and a method for producing the same. [Background technology]

[0002] Suede-like artificial leather is generally composed of a fiber-entangled body containing a nonwoven fabric made of polyester-based fibers as a component, and a polymeric elastomer, and is used in a wide range of fields such as automobile interior materials, furniture, miscellaneous goods, clothing, etc. From the viewpoint of design, artificial leather is often colored, and dyeing with chemical dyes, particularly disperse dyes, is a common method for dyeing polyester-based fibers. On the other hand, in recent years, there has been an increasing demand for environmental considerations, and dyeing techniques that use dyes derived from natural sources (natural dyes) rather than chemical dyes are required for dyeing artificial leather. Natural dyes are obtained from plants and animals and have a lower environmental impact than chemical dyes. However, when dyeing synthetic fibers, there is generally an issue of low wash fastness and low light fastness.

[0003] As a technique for solving such problems, for example, Patent Documents 1 and 2 propose a production method for dyeing synthetic fibers including polyester fibers by using a cationic compound in combination to improve washing fastness and a chemical dye in combination to improve light fastness. On the other hand, Patent Document 3 proposes a manufacturing method in which polyester fibers can be dyed with natural dyes without metal mordants by setting the dyeing temperature within a specific range. According to this invention, polyester fibers with subdued colors can be obtained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-127536 [Patent Document 2] JP 2012-233081 A [Patent Document 3] Japanese Patent Application Publication No. 10-072787 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the dyed products obtained by the methods disclosed in Patent Documents 1 and 2 are suppressed from discoloring / fading due to washing or exposure to light, they are not dyed using only natural dyes, and therefore have the problem that the environmental impact cannot be significantly reduced. Conversely, the dyed product obtained by the method disclosed in Patent Document 3 can be dyed only with natural dyes, but has the problem that it is not resistant to discoloration / fading due to washing or exposure to light.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an artificial leather that can be dyed only with naturally derived dyes and yet has both good washing fastness and good light fastness. [Means for solving the problem]

[0007] Means for Solving the Problems The present inventors have conducted intensive research in order to achieve the above-mentioned object, and have discovered that, for a sheet including a polymer elastomer and a fiber-entangled body including, as a component, a nonwoven fabric made of dye-containing polyester fibers, by setting the dyeing temperature within a certain range and adopting a structure in which naturally occurring dyes penetrate into the polyester fibers, it is possible to obtain artificial leather that is dyed only with naturally occurring dyes and that has both good wash fastness and good light fastness. The present invention has been completed based on these findings, and provides the following inventions.

[0008] [1] An artificial leather comprising a fiber entanglement body containing a nonwoven fabric made of dye-containing polyester fibers as a component, and a polymer elastomer, wherein the proportion of naturally derived dyes in the dye is 98% by mass or more and 100% by mass or less, and the artificial leather has a washing fastness (discoloration) of grade 3 or higher as defined by the AATCC-61-2006 1-A method, and a light fastness of grade 3 or higher as defined by JIS L0842:2021. [2] The artificial leather according to [1], wherein the artificial leather contains a cationic compound. [3] The artificial leather according to [1] or [2], wherein the polyester-based fiber further contains an ultraviolet absorbing agent. [4] The artificial leather according to any one of [1] to [3] above, wherein the fiber-entangled body further contains a woven or knitted fabric as a component. [5] The artificial leather according to any one of [1] to [4], wherein the mass ratio of the polymer elastomer to the artificial leather is 2 mass % or more and 50 mass % or less. [6] The artificial leather according to any one of [1] to [5] above, wherein the average single fiber diameter of the polyester-based fibers is 1.0 μm or more and 10.0 μm or less. [7] A method for producing artificial leather, comprising dyeing a sheet containing a fiber-entangled body including a nonwoven fabric made of polyester-based fibers as a component and a polymer elastomer using a dye formulation in which the ratio of dyes of natural origin to the total dye is 98% by mass or more and 100% by mass or less, and under conditions in which the maximum temperature of the dye solution in the dye bath is 100°C or more and 130°C or less, to obtain artificial leather having a washing fastness (discoloration) of grade 3 or more as specified by the AATCC-61-2006 1-A method and a light fastness of grade 3 or more as specified by JIS L0842:2021. [8] The method for producing an artificial leather according to [7] above, further comprising the step of adding a cationic compound to the sheet before the dyeing and / or in the same bath as the dyeing. [9] The method for producing an artificial leather according to [7] or [8] above, wherein an ultraviolet absorber is applied to the sheet before the dyeing and / or in the same bath as the dyeing. Effect of the Invention

[0009] According to the present invention, an artificial leather containing a nonwoven fabric made of polyester fiber as a component and dyed only with dyes of natural origin can be obtained. In particular, the artificial leather of the present invention has a feature of being able to achieve both washing fastness and light fastness, and therefore can be suitably used for miscellaneous goods, small items, clothing, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The artificial leather of the present invention is an artificial leather consisting of a fiber entanglement body containing as a component a nonwoven fabric made of dye-containing polyester fibers, and a polymer elastomer, in which the proportion of naturally derived dyes in the dye is 98% by mass or more and 100% by mass or less, and the artificial leather has a washing fastness (discoloration) of grade 3 or more as defined by the AATCC-61-2006 1-A method, and a light fastness of grade 3 or more as defined by JIS L0842:2021. The components are described in detail below, but the present invention is not limited to the scope described below as long as it does not exceed the gist of the present invention, and various modifications are possible without departing from the gist of the present invention.

[0011] [Fiber entanglement] The fiber-entangled body according to the present invention includes a nonwoven fabric made of polyester fibers as a component. In the present invention, the polyester fibers refer to fibers made of a polyester resin described below. The polyester resin refers to a resin in which the molar fraction of the polyester units in the repeating units is 80 mol % to 100 mol %. Examples of the polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polyethylene-1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate, polylactic acid, etc. Among them, polyethylene terephthalate, which is the most widely used, or a polyester copolymer mainly containing ethylene terephthalate units, i.e., the molar fraction of the ethylene terephthalate units in the repeating units is 50 mol% to 99 mol% is preferably used as the polyester resin.

[0012] As the polyester-based resin, a single polyester or two or more different polyesters may be used. When two or more different polyesters are used, from the viewpoint of compatibility of the two or more components, it is preferable that the difference in intrinsic viscosity (IV value) of the polyesters used is 0.50 or less, and more preferably 0.30 or less. In the present invention, the intrinsic viscosity of the polyester resin is a value calculated by the following method. (1) Dissolve 0.8 g of the sample polymer in 10 mL of orthochlorophenol. (2) Relative viscosity η measured using an Ostwald viscometer at a temperature of 25°C r Calculate using the formula below and round off to the third decimal place. η r = η / η 0 =(t × d) / (t 0 ×d 0 ) Intrinsic viscosity (IV value) = 0.0242 η r +0.2634 (Here, η is the viscosity of the polymer solution, η 0 is the viscosity of orthochlorophenol, t is the time it takes for the solution to fall (sec), and d is the density of the solution (g / cm 3 ), t 0 is the fall time of orthochlorophenol (seconds), d 0 is the density of orthochlorophenol (g / cm3 ) and

[0013] In the present invention, the polyester resin may contain carbon black. Carbon black is easy to obtain a black pigment with a fine particle size and has excellent dispersibility in polymers. Therefore, by containing carbon black, an artificial leather having excellent deep and uniform color development, excellent color fastness and abrasion resistance can be obtained. In addition to carbon black, inorganic particles such as titanium oxide particles, lubricants, heat stabilizers, conductive agents, heat storage agents, antibacterial agents, and the like can be added to the polyester resin according to various purposes, within the scope of not impairing the object of the present invention.

[0014] Next, the polyester fiber according to the present invention preferably has an average single fiber diameter of 1.0 μm or more and 10.0 μm or less. By having the average single fiber diameter of the polyester fiber be 1.0 μm or more, preferably 1.5 μm or more, the artificial leather has excellent color development after dyeing, light fastness and friction fastness, and stability during spinning. On the other hand, by having the average single fiber diameter of the polyester fiber be 10.0 μm or less, preferably 6.0 μm or less, more preferably 4.5 μm or less, the artificial leather has a dense feel, is soft, and has excellent surface quality. From the viewpoint of processing operability, the cross-sectional shape of the polyester-based fiber is preferably a round cross-section, but cross-sectional shapes of irregular cross-sections such as an ellipse, a polygon such as a "triangle, a square, a pentagon, or a hexagon" (including those with rounded corners), a sector, a cross, a hollow, a Y-shape, a T-shape, or a U-shape may also be used.

[0015] In the present invention, the average single fiber diameter of polyester fibers is calculated by taking a scanning electron microscope (SEM, for example, Keyence Corporation's "VHX-D500 / D510 type") photograph of the cross section of the artificial leather, randomly selecting 10 polyester fibers that are circular or elliptical and close to circular, measuring the single fiber diameter, calculating the arithmetic average value of the 10 fibers, and rounding off to the first decimal place. However, when a polyester fiber with a modified cross section is used, the cross section area of ​​the single fiber is first measured, and the diameter (circle equivalent diameter) is calculated when the cross section is considered to be circular to obtain the diameter of the single fiber.

[0016] The polyester fiber according to the present invention preferably further contains an ultraviolet absorber. By containing an ultraviolet absorber in the polyester fiber, decomposition of the naturally derived dye contained in the polyester fiber by ultraviolet light can be suppressed, and the light fastness can be improved. The ultraviolet absorber used in the present invention refers to a compound having a structure that can absorb ultraviolet light, become excited, and release the energy of the ultraviolet light as thermal energy. Specifically, benzotriazole-based compounds having a benzotriazole group such as "2-(2'-hydroxy-5'-methylphenyl)benzotriazole" and triazine-based compounds such as "2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol" can be used.

[0017] The fiber-entangled body according to the present invention contains a nonwoven fabric made of the polyester-based fibers as a constituent element. In the present invention, the term "a fiber-entangled body containing a nonwoven fabric as a constituent element" refers to an embodiment in which the fiber-entangled body is composed only of a nonwoven fabric, or an embodiment in which the fiber-entangled body further contains a woven or knitted fabric as a constituent element, as described below, for example, an embodiment in which the fiber-entangled body is formed by entanglement of a nonwoven fabric and a woven or knitted fabric. The fiber-entangled body containing a nonwoven fabric as a constituent element can provide a uniform and elegant appearance and texture when the surface is raised.

[0018] The nonwoven fabric generally has a long fiber nonwoven fabric mainly composed of filaments and a short fiber nonwoven fabric mainly composed of fibers having a fiber length of 100 mm or less. When the fibrous substrate is a long fiber nonwoven fabric, it is preferable because it produces an artificial leather with excellent strength. On the other hand, when the fibrous substrate is a short fiber nonwoven fabric, it is possible to increase the fibers oriented in the thickness direction of the artificial leather compared to the case of a long fiber nonwoven fabric, and therefore, when the surface is raised, it produces an artificial leather with a high density on the surface.

[0019] In the artificial leather of the present invention, the fiber-entangled body further includes a woven or knitted fabric as a component, and for example, as described above, an embodiment in which the nonwoven fabric and the woven or knitted fabric are entangled and integrated is also preferred. In this way, an artificial leather with improved strength and shape stability is obtained. Examples of the fiber-entangled body "further including a woven or knitted fabric as a component" include a structure in which the fiber-entangled body is laminated in the order of nonwoven fabric / woven or knitted fabric, a structure in which the fiber-entangled body is laminated in the order of nonwoven fabric / woven or knitted fabric / nonwoven fabric, and a structure in which the fiber-entangled body is laminated in the order of nonwoven fabric / woven or knitted fabric / woven or knitted fabric. Among these, from the viewpoint of the surface quality and strength of the artificial leather, a structure in which the fiber-entangled body is laminated in the order of nonwoven fabric / woven or knitted fabric, and a structure in which the fiber-entangled body is laminated in the order of nonwoven fabric / woven or knitted fabric / nonwoven fabric are more preferred.

[0020] In the present invention, the woven or knitted fabric is a general term for woven fabrics and knitted fabrics. When the woven or knitted fabric is a woven fabric, examples of the weave structure include plain weave, twill weave, satin weave, etc., and when the woven or knitted fabric is a knitted fabric, examples of the knit structure include weft knits such as "plain knit, rib knit, pearl knit" and warp knits such as "single denbigh knit, single atlas knit, single cord knit, double denbigh knit, double atlas knit, double cord knit, half tricot knit". Among them, when the woven fabric has a plain weave structure, it is particularly preferable because it can be made into an artificial leather with excellent strength. As the type of fiber constituting the woven or knitted fabric, it is preferable to use filament yarn, spun yarn, a mixed composite yarn of filament yarn and spun yarn, etc., and from the viewpoint of abrasion resistance, particularly mechanical strength, etc., it is more preferable to use a multifilament made of a polyester-based resin or a polyamide-based resin.

[0021] The average single fiber diameter of the fibers constituting the woven or knitted fabric is preferably 1.0 μm or more and 50.0 μm or less. By making the average single fiber diameter of the fibers constituting the woven or knitted fabric preferably 50.0 μm or less, more preferably 40.0 μm or less, and even more preferably 30.0 μm or less, not only can the artificial leather have excellent flexibility, but also, even if the fibers of the woven or knitted fabric are exposed on the surface of the artificial leather, the hue difference with the polyester fibers of the nonwoven fabric after dyeing is small, so that the artificial leather does not lose the uniformity of the hue of the surface. On the other hand, by making the average single fiber diameter preferably 1.0 μm or more, more preferably 8.0 μm or more, and even more preferably 9.0 μm or more, the shape stability of the product, at least a part of which is the artificial leather of the present invention, is improved.

[0022] In the present invention, the average single fiber diameter of the fibers constituting the woven or knitted fabric is calculated by taking a scanning electron microscope (SEM) photograph of the cross section of the artificial leather, randomly selecting 10 fibers constituting the woven or knitted fabric, measuring the single fiber diameter of the selected fibers, calculating the arithmetic average value of the 10 fibers, and rounding off to one decimal place.

[0023] When the fibers constituting the woven or knitted fabric are multifilament, the total fineness of the multifilament is measured according to "8.3.1 Correct fineness b) Method B (simplified method)" of "8.3 Fineness" of JIS L1013:2010 "Testing methods for chemical fiber filament yarns," and the total fineness is preferably 30 dtex or more and 170 dtex or less. The total fineness of the multifilaments is 170 dtex or less, which results in an artificial leather with excellent flexibility. On the other hand, the total fineness of the multifilaments is 30 dtex or more, which not only improves the shape stability of the product at least a part of which is the artificial leather of the present invention, but also makes it difficult for the fibers constituting the woven or knitted fabric to be exposed on the surface of the artificial leather when the nonwoven fabric and the woven or knitted fabric are entangled and integrated by needle punching or the like, which results in an artificial leather with excellent design, which is preferable.

[0024] Furthermore, the twist number of the yarns constituting the woven or knitted fabric is preferably 1000 T / m or more and 4000 T / m or less. By having the twist number of 4000 T / m or less, more preferably 3500 T / m or less, and even more preferably 3000 T / m or less, an artificial leather with excellent flexibility is obtained, and by having the twist number of 1000 T / m or more, more preferably 1200 T / m or more, and even more preferably 1300 T / m or more, damage to the fibers constituting the woven or knitted fabric can be prevented when the nonwoven fabric and the woven or knitted fabric are entangled and integrated by needle punching or the like, and an artificial leather with excellent mechanical strength is obtained, which is preferable.

[0025] [Polymer elastomer] The artificial leather of the present invention contains a polymeric elastomer. In the present invention, "containing a polymeric elastomer" refers to a state in which a polymeric elastomer is contained in the central 40% of the artificial leather, excluding 30% of the thickness direction from both surfaces excluding the napped portions, and can be determined by the following procedures (1) to (7). (1) With the napped surface of the artificial leather laid down using a lint brush or the like, a thin section 1 mm thick is prepared in the cross-sectional direction of the artificial leather from a randomly selected position on the artificial leather. (2) Using a scanning electron microscope (SEM, for example, Keyence Corporation's VHX-D500 / D510), observe the cross section of the thin section of (1), excluding 30% of the cross section from both surfaces in the thickness direction, and the remaining central 40%. (3) In the SEM images taken, the presence or absence of any substances other than the fibers that make up the fiber-entangled structure is confirmed. (4) If there are any substances other than the fibers that make up the fiber-entangled body, remove them by peeling off the substances applied to the surface layer of the artificial leather. (5) Remove 30% of the thickness of both surfaces of the artificial leather, excluding the napped portions, by polishing or other means, leaving only the central 40%. (6) The test piece (5) is dissolved in N,N-dimethylformamide (DMF) and hexafluoro-2-propanol (HFIP), and the presence or absence of the polymer elastomer is confirmed by performing a composition analysis of the solute in the DMF solution after dissolution and the insoluble matter in HFIP. In the composition analysis, the presence or absence of the polymer elastomer is confirmed by, for example, infrared spectroscopy (IR) or the like. (7) When the structure of a polymer elastomer described below can be confirmed in either the solute in the DMF solution or the insoluble matter in HFIP, it is deemed to contain a polymer elastomer.

[0026] Since this polymeric elastomer is a binder that holds the polyester fibers that make up the artificial leather, in consideration of the soft feel of the artificial leather of the present invention, it is preferable to use polyurethane as the main component of the polymeric elastomer used. Note that, in the present invention, "main component" means that the mass of polyurethane is more than 50 mass% of the total mass of the polymeric elastomer.

[0027] In the present invention, the polyurethane resin preferably used as the polymeric elastomer can be either an organic solvent-based polyurethane resin used in a state dissolved in an organic solvent, or a water-dispersed polyurethane resin used in a state dispersed in water. Here, in the present invention, the water-dispersed polyurethane resin refers to a polyurethane resin having a hydrophilic group and a solubility in DMF of less than 40g / 100g-DMF (less than 40g of the polyurethane can be dissolved in 100g of DMF). Conversely, a polyurethane resin having a solubility in DMF of 40g / 100g-DMF or more (more than 40g of the polyurethane can be dissolved in 100g of DMF) is considered to be an organic solvent-based polyurethane resin.

[0028] In addition, examples of polyurethane resins that can be preferably used in the present invention include polyurethane resins obtained by reacting a polymer diol, an organic diisocyanate, and a chain extender. Each of these will be described below.

[0029] <1> Polymer Diol As the above-mentioned polymer diol, for example, polycarbonate-based diol, polyester-based diol, polyether-based diol, silicone-based diol and fluorine-based diol can be adopted, and copolymers of these can also be used. Among them, from the viewpoint of hydrolysis resistance and abrasion resistance, it is more preferable to use polycarbonate-based diol. When the molecular weight of the polyurethane resin 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, it is possible to prevent the artificial leather from becoming hard. In addition, by setting the number average molecular weight to preferably 4000 or less, more preferably 3000 or less, it is possible to maintain the strength of the polyurethane resin.

[0030] <2> Organic Diisocyanates Examples of organic diisocyanates preferably used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, and aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, and these can also be used in combination.

[0031] <3> Chain extender The chain extender preferably used in the present invention is preferably an amine-based chain extender such as ethylenediamine or methylenebisaniline, or a diol-based chain extender such as ethylene glycol. Also, a polyamine obtained by reacting a polyisocyanate with water can be used as the chain extender.

[0032] <4> Other Ingredients In the present invention, the polyurethane resin preferably used as the polymeric elastomer can be used in combination with a crosslinking agent for the purpose of improving water resistance, abrasion resistance, hydrolysis resistance, etc. The crosslinking agent may be an external crosslinking agent added to the polyurethane resin as a third component, or an internal crosslinking agent that introduces reactive points that will become a crosslinked structure in advance into the molecular structure of the polyurethane resin can be used. The internal crosslinking agent is more preferable from the viewpoint of reducing the decrease in flexibility because it can form uniform crosslinking points in the molecular structure of the polyurethane resin. In addition, the polymer elastomer may contain various additives depending on the purpose, for example, flame retardants such as "phosphorus-based, halogen-based, and inorganic-based" antioxidants, such as "phenol-based, sulfur-based, and phosphorus-based" antioxidants, ultraviolet absorbers such as "benzotriazole-based, triazine-based, benzophenone-based, salicylate-based, cyanoacrylate-based, and oxalic acid anilide-based" ultraviolet absorbing agents, such as "hindered amine-based and benzoate-based" light stabilizers, hydrolysis-resistant stabilizers such as "carbodiimide-based and oxazoline-based", plasticizers, antistatic agents, surfactants, coagulation adjusters, carbon black, and dyes.

[0033] In general, the content of the polymer elastomer in the artificial leather can be appropriately adjusted in consideration of the type of polymer elastomer used, the manufacturing method of the polymer elastomer, and the texture and physical properties, but in the present invention, the content of the polymer elastomer is preferably 2% by mass or more and 50% by mass or less based on the mass of the artificial leather. By making the content of the polymer elastomer 2% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, it is possible to not only strengthen the bond between the fibers by the polymer elastomer, but also to perform dyeing with a low dye concentration. On the other hand, by making the content of the polymer elastomer 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, it is possible to obtain an artificial leather with a soft texture, and to suppress dye contamination of other fabrics that are washed at the same time during washing.

[0034] In the present invention, the content (mass %) of the polymer elastomer in the artificial leather is a value measured and calculated by the following procedure. (1) Randomly take three test pieces measuring 10 cm x 10 cm from the artificial leather. (2) If there is a substance applied to the surface of the artificial leather, remove that layer by peeling it off, etc. (3) In the method (7) for confirming whether or not the polymer elastomer is contained, if the structure of the polymer elastomer is confirmed on the solute side in the DMF solution, carry out step (5), and if the structure of the polymer elastomer is confirmed on the insoluble side of the HFIP, carry out step (6) to calculate the content of the polymer elastomer. If the structure of the polymer elastomer is confirmed in both DMF and HFIP, the larger of the values ​​calculated in steps (5) and (6) is used as the content of the polymer elastomer. (4) The test piece is immersed in DMF and dried at 25° C. for 24 hours. The mass ratio of the test piece before and after dissolution is calculated using the following formula, and the arithmetic average value (%) of the three test pieces is rounded off to the first decimal place to calculate the content of the polymer elastomer. (Sample mass before dissolution (g) - Sample mass after dissolution and drying (g)) / (Sample mass before dissolution (g)) x 100 (5) The test piece is immersed in HFIP and dried at 25° C. for 24 hours. The mass ratio of the test piece before and after dissolution is calculated using the following formula, and the arithmetic average value (%) of the three test pieces is rounded off to the first decimal place to calculate the content of the polymer elastomer. (Sample mass after dissolution (g)) / (Sample mass before dissolution (g)) x 100

[0035] [Artificial leather] The artificial leather of the present invention includes the fiber-entangled body and the polymeric elastomer. The artificial leather of the present invention has a ratio of naturally derived dyes in the dyes contained in the polyester-based fibers of 98% by mass or more and 100% by mass or less. Here, in the present invention, the ratio of naturally derived dyes contained in the polyester-based fibers is 14 The value is obtained by measuring the C concentration and is measured and calculated according to the following procedure. (1) The artificial leather is immersed in methanol and squeezed several times to obtain a methanol extract of the dye, and the methanol is removed by evaporation to obtain the dye contained in the artificial leather. (2) The carbon isotopes ( 12 C. 13 C. 14 C) are separated using the mass difference of the atoms, and the abundance of each isotope atom is measured. (3) The proportion of naturally occurring dyes in the dye was calculated by rounding off the first decimal place using the following formula for the abundance of the obtained isotope atoms. Proportion of naturally derived dyes in dyes = ( 14 C(sample) / 14 C (standard material))×100

[0036] Next, the artificial leather of the present invention has a washing fastness (discoloration) of grade 3 or higher as defined by the AATCC-61-2006 1-A method, and a light fastness of grade 3 or higher as defined by JIS L0842:2021. Details are described below.

[0037] First, the artificial leather of the present invention has a washing fastness (discoloration) of grade 3 or higher as specified by the AATCC-61-2006 1-A method. The upper limit is grade 5. When the discoloration of the artificial leather in the washing fastness measurement is grade 3 or higher, the color does not fade even after repeated washing, and good color development can be maintained. Moreover, the artificial leather of the present invention preferably has a washing fastness (staining) of grade 3 or higher as specified by the AATCC-61-2006 1-A method, with the upper limit being grade 5. When the staining on cotton fabric in the washing fastness measurement is grade 3 or higher, the color does not transfer to other clothes during washing, and the artificial leather can be handled in the same way as ordinary clothes and miscellaneous goods.

[0038] In the present invention, the washing fastness (discoloration) of the artificial leather as defined by the AATCC-61-2006 1-A method and the washing fastness (staining) as defined by the AATCC-61-2006 1-A method are measured and calculated as follows. (1) Randomly take test pieces measuring 5 cm x 10 cm from the artificial leather. (2) Place the brushed side facing up, place a multifiber standard attachment cloth (a cloth containing six types of fibers: acetate, cotton, polyamide, polyester, acrylic, and wool) conforming to the AATCC standard on top, and sew the edges together to create the test cloth. (3) Place the test cloth and 100 mL of 5 g / L soap solution in the test bottle, set the test bottle in a laundermeter-type washing test machine, and wash at 40°C for 45 minutes. (4) After removing the test cloth and rinsing it with water, the discoloration of the surface of the artificial leather on which the standard multi-fiber cloth was attached is graded using a gray scale for discoloration (specified in JIS L0804:2004 "Gray scale for discoloration"). Also, the staining of the surface of the standard multi-fiber cloth on which the artificial leather was attached is graded using a gray scale for staining (specified in JIS L0805:2005 "Gray scale for staining"). At this time, if the degree of staining of the standard multi-fiber cloth varies among the six fibers, the staining grade of the fiber with the lowest grade is used as the staining grade. In order to make the washing fastness (discoloration) of artificial leather grade 3 or higher as specified by the AATCC-61-2006 1-A method, the dyeing temperature should be within the range described below to increase the amount of dye present in the polyester fiber, a cationic compound should be added to strengthen the adhesion of the dye to the polyester fiber, or a resin should be added after dyeing to make the dye less likely to fall off, and it is particularly preferable to increase the amount of dye in the polyester fiber or to strengthen the adhesion of the dye. In order to make the washing fastness (staining) of artificial leather grade 3 or higher as specified by the AATCC-61-2006 1-A method, the dyeing temperature should be within the range described below to increase the amount of dye present in the polyester fiber, a cationic compound should be added to strengthen the adhesion of the dye to the polyester fiber, a resin should be added after dyeing to make the dye less likely to fall off, or a natural dye that does not stain other fibers even if it falls off should be used.

[0039] The artificial leather of the present invention has a light fastness of grade 3 or higher as specified in JIS L0842:2021. The upper limit is grade 5. When the discoloration of the artificial leather in the light fastness measurement is grade 3 or higher, fading of the artificial leather due to natural light can be suppressed. In the present invention, the light fastness of the artificial leather as defined in JIS L0842:2021 is measured and calculated as follows. (1) Randomly take two test pieces measuring 3 cm x 6.5 cm from the artificial leather. (2) With the brushed side facing out, two test pieces are subjected to level 3 and level 4 irradiation in a carbon arc light resistance tester, and the level is determined by comparing with the discoloration on the blue scale.

[0040] Furthermore, in order to achieve a light fastness of grade 3 or higher as specified in JIS L0842:2021 for artificial leather, it is possible to select dyes of natural origin that are less likely to be decomposed by ultraviolet light, to increase the amount of dye present in the polyester fiber by adjusting the dyeing temperature, or to add ultraviolet absorbers and antioxidants.

[0041] The artificial leather of the present invention preferably contains a cationic compound. By adhering the cationic compound to the surface of the artificial leather, it is possible to prevent the dye from coming off during washing and to suppress discoloration of the artificial leather during washing. The cationic compound used in the present invention is a general term for organic compounds that form cations when dissolved in water. Specific examples include basic amine compounds such as "polyvinylamine, polyallylamine", ammonium salt compounds such as "quaternary ammonium salts, tertiary amine salts", and basic amino acids such as "lysine, arginine".

[0042] In the artificial leather of the present invention, the weight of the artificial leather is 100 g / m 2 More than 600g / m 2 The weight of the artificial leather is preferably 100 g / m 2 More preferably, 150 g / m 2This makes it possible to produce an artificial leather that combines a thick design, abrasion resistance, and strength as a fabric. 2 Less than 550 g / m 2 This results in an artificial leather with excellent flexibility. In the present invention, the weight per unit area of ​​the artificial leather is measured and calculated as follows. (1) Randomly take three test pieces measuring 5 cm x 5 cm from the artificial leather. (2) Measure the mass of the artificial leather to one decimal place. (3) Divide the mass of the artificial leather by the area of ​​the test piece to calculate the basis weight of each artificial leather sample. The arithmetic average value (g / m2) of the three test pieces is calculated. 2 ) is rounded off to the first decimal place to calculate the weight of the artificial leather.

[0043] [Manufacturing method of artificial leather] A preferred embodiment of the method for producing the artificial leather of the present invention is a method for dyeing a sheet containing a fiber entanglement body containing a nonwoven fabric made of polyester fibers as a component and a polymeric elastomer using a dye blend in which the proportion of naturally derived dyes is 98% by mass or more and 100% by mass or less, and the maximum temperature of the dyeing solution in the dye bath is 100 ° C. or more and 130 ° C. or less, to obtain an artificial leather having a washing fastness (discoloration) of 3 or more as defined by the AATCC-61-2006 1-A method and a light fastness of 3 or more as defined by JIS L0842:2021. Each of the above steps will be described in more detail below.

[0044] (a) forming a sheet The sheet including the fiber-entangled body containing, as a component, a nonwoven fabric made of polyester fibers, and the polymeric elastomer can be preferably formed as follows. First, in regard to the fiber entanglement, in order to form a nonwoven fabric made of polyester fibers, there can be mentioned a method of directly spinning polyester fibers having the above-mentioned average single fiber diameter into a nonwoven fabric, a method of first forming ultrafine fiber-developing fibers into a nonwoven fabric, and then developing polyester fibers having the above-mentioned average single fiber diameter from the nonwoven fabric, etc. Among them, from the viewpoint of excellent operability and ability to obtain fibers having a uniform single fiber diameter, it is preferable to adopt the method of first forming a nonwoven fabric using ultrafine fiber-developing fibers.

[0045] As the ultrafine fiber-producing fiber, an islands-in-sea type composite fiber is used, in which thermoplastic resins having different solvent solubilities are used as a sea part (easily soluble polymer) and an island part (slightly soluble polymer), and the sea part is dissolved and removed using a solvent or the like to make the island parts into polyester-based fibers having the above-mentioned average single fiber diameter. The use of islands-in-sea type composite fiber is preferable from the viewpoint of the soft feel and surface quality of the artificial leather, because it is possible to provide appropriate gaps between the island parts, i.e., between the ultrafine fibers inside the fiber bundle, when the sea part is removed. As a method for spinning ultrafine fiber-producing fibers having an islands-in-sea type composite structure, a method using a spinneret for islands-in-sea type composite fibers, in which the sea part and the island part are mutually arranged and spun, is preferred from the viewpoint of obtaining ultrafine fibers with a uniform single fiber diameter.

[0046] As the sea component of the islands-in-sea type composite fiber, polyethylene, polystyrene, copolymer polyesters copolymerized with "sodium sulfoisophthalic acid or polyethylene glycol," etc., polylactic acid, polyvinyl alcohol, and copolymers thereof, etc. can be used. From the viewpoints of spinnability, ease of elution, etc., polystyrene and copolymer polyesters are preferably used.

[0047] In the method for producing the artificial leather of the present invention, it is preferable to use islands-in-sea type composite fibers in which the strength of the island components is 2.0 cN / dtex or more. By making the strength of the island components 2.0 cN / dtex or more, more preferably 2.3 cN / dtex or more, and further preferably 2.8 cN / dtex or more, the abrasion resistance of the artificial leather can be improved and the decrease in friction fastness due to the falling off of fibers can be suppressed. In the present invention, the strength of the island components of the islands-in-sea type composite fiber is calculated by the following method. (1) Ten islands-in-the-sea composite fibers, each 20 cm long, are bundled together. (2) After dissolving and removing the sea component from the sample (1), air-dry it. (3) In accordance with JIS L1013:2010 "Test methods for chemical fiber filament yarn", "8.5 Tensile strength and elongation", "8.5.1 Standard time test", the test shall be carried out 10 times under the conditions of a grip length of 5 cm, a pulling speed of 5 cm / min, and a load of 2 N (N=10). (4) The arithmetic mean value (cN / dtex) of the test results obtained in (3) above, rounded off to one decimal place, shall be the strength of the island components of the islands-in-sea type composite fiber.

[0048] The spun ultrafine fiber-developing fibers are then opened and formed into a fiber web by a cross wrapper or the like, and entangled to obtain a fiber-entangled body containing a nonwoven fabric as a constituent element. Methods that can be used to obtain a fiber-entangled body containing a nonwoven fabric as a constituent element by entangling the fiber web include needle punching and water jet punching. As for the form of the nonwoven fabric, either a short fiber nonwoven fabric or a long fiber nonwoven fabric can be used as described above. In the case of a short fiber nonwoven fabric, the number of fibers oriented in the thickness direction of the artificial leather is greater than in the case of a long fiber nonwoven fabric, and it is possible to obtain a high degree of density and a soft texture on the surface of the artificial leather when it is raised.

[0049] When a staple fiber nonwoven fabric is used as the nonwoven fabric, the islands-in-sea type composite fibers obtained in the step of forming the islands-in-sea type composite fibers are preferably subjected to a crimping process, cut to a predetermined length to obtain raw cotton, and then opened, laminated, and entangled to obtain a staple fiber nonwoven fabric. The crimping process and cutting process can be performed by known methods.

[0050] When using a short fiber nonwoven fabric, the average fiber length of the ultrafine fiber-developing fiber (the polyester fiber in the resulting artificial leather) is preferably 25 mm or more and 90 mm or less. By making the average fiber length 90 mm or less, more preferably 80 mm or less, and even more preferably 70 mm or less, good quality and soft feel can be obtained. On the other hand, by making the average fiber length 25 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more, an artificial leather with excellent abrasion resistance can be obtained.

[0051] Furthermore, when a woven or knitted fabric is to be included in the fiber entanglement body, the nonwoven fabric obtained by the above-mentioned method and the woven or knitted fabric can be laminated and integrated. The nonwoven fabric and the woven or knitted fabric can be integrated by laminating the woven or knitted fabric on one or both sides of the nonwoven fabric, or by sandwiching the woven or knitted fabric between multiple sheets of nonwoven fabric and then entangling the fibers of the nonwoven fabric and the woven or knitted fabric by needle punching, water jet punching, or the like.

[0052] The basis weight of the fiber entanglement or nonwoven fabric constituting the artificial leather according to the present invention is 50 g / m2, as measured according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General nonwoven fabric test method". 2 More than 700g / m 2 The nonwoven fabric or fiber entanglement body preferably has a basis weight of 50 g / m or less. 2 More preferably, 80 g / m 2 When the weight of the nonwoven fabric or the fiber-entangled body is 700 g / m or more, the artificial leather has a sense of fullness and excellent texture. 2 Less than 600g / m 2 The artificial leather will be flexible if it meets the following requirements.

[0053] The apparent density of the nonwoven fabric made of islands-in-the-sea type composite fibers after needle punching or water jet punching is 0.15 g / cm 3 More than 0.45g / cm 3 The apparent density is preferably 0.15 g / cm or less. 3 By setting the density to 0.45 g / cm or more, the artificial leather can have sufficient shape stability and dimensional stability. 3 By setting the thickness to the range below, a sufficient space for imparting the polymeric elastomer can be maintained, and voids in the cross section can be maintained, thereby achieving a soft feel. It is also a preferred embodiment that the fiber entanglement is subjected to a heat shrinkage treatment with hot water or steam in order to improve the denseness of the fibers.

[0054] The water-soluble resin can also be added by impregnating the fiber-entangled body with an aqueous solution of the water-soluble resin and drying it. By adding the water-soluble resin to the fiber-entangled body, the fibers are fixed and the dimensional stability is improved. Here, in the present invention, the water-soluble resin refers to a resin that is soluble in water or hot water (meaning water at 80°C to 100°C), and specific examples thereof include polyacrylamide, polyvinyl alcohol, and carboxymethyl cellulose.

[0055] The fiber entanglement is then treated with a solvent or solution, which is one method for forming polyester fibers having an average single fiber diameter of 1.0 μm to 10.0 μm. The formation of polyester fibers by this method can be carried out by immersing the above-mentioned fiber entanglement in a solvent or solution to dissolve and remove the sea component of the islands-in-sea type composite fiber.

[0056] As a solvent for dissolving and removing the sea component, when the sea component is polyethylene or polystyrene, an organic solvent such as toluene or trichloroethylene can be used. When the sea component is a copolymer polyester or polylactic acid, an alkaline aqueous solution such as sodium hydroxide can be used. When the sea component is a water-soluble thermoplastic polyvinyl alcohol resin, hot water can be used.

[0057] Then, the fiber-entangled body, the main component of which is polyester-based fibers or ultrafine fiber-developing fibers (island-in-sea composite fibers), is impregnated with a solution of the polymer elastomer, and the polymer elastomer is solidified to form a sheet containing the fiber-entangled body and the polymer elastomer. As a method for solidifying the polymer elastomer, there is a method in which the fiber-entangled body is impregnated with a solution of the polymer elastomer, and then the solution is wet-coagulated or dry-coagulated, and these methods can be appropriately selected depending on the type of polymer elastomer used.

[0058] When polyurethane is selected as the polymeric elastomer, the solvent preferably used is N,N-dimethylformamide, dimethylsulfoxide, etc., when the polyurethane is an organic solvent-based polyurethane resin. When the polyurethane is a water-dispersed polyurethane resin, a water-dispersed polyurethane liquid in which the polyurethane is dispersed in water as an emulsion may be used. The polymer elastomer may be applied to the fiber-entangled body before polyester-based fibers are generated from the ultrafine fiber-producing fiber (island-in-sea type composite fiber) or after polyester-based fibers are generated from the ultrafine fiber-producing fiber (island-in-sea type composite fiber).

[0059] Next, one surface of the obtained sheet is ground to form a sheet having nap. From the viewpoint of production efficiency, it is also a preferred embodiment to cut the sheet in half in the thickness direction into two sheets before grinding the surface of the sheet. Then, one surface of the sheet (including the half-cut sheet) can be ground with sandpaper, a roll sander, etc. to form a napped sheet. As described above, it goes without saying that both surfaces can be ground to form napped surfaces on both sides. A lubricant such as a silicone emulsion may be applied to the surface of the sheet prior to grinding.

[0060] (b) Dyeing the sheets Next, a sheet containing a fiber entanglement body containing the nonwoven fabric made of polyester-based fibers as a component and a polymer elastomer is dyed using a dye formulation in which the proportion of naturally derived dyes is 98% by mass or more and 100% by mass or less, and the maximum temperature of the dyeing solution in the dye bath is 100°C or more and 130°C or less, to obtain an artificial leather having a washing fastness (discoloration) of grade 3 or more as specified by the AATCC-61-2006 1-A method and a light fastness of grade 3 or more as specified by JIS L0842:2021.

[0061] In the method for producing the artificial leather of the present invention, first, a dye blend is used in which the ratio of naturally derived dyes to the total dyes is 98% by mass or more and 100% by mass or less. There is no particular restriction on the naturally derived dyes used in the present invention, and they are appropriately selected according to the desired hue of the resulting artificial leather. Only one type of naturally derived dye may be used, or two or more types may be mixed together. The naturally derived dye to be mixed with the naturally derived dye may be any of plant-derived dyes, animal-derived dyes, and mineral-derived dyes.

[0062] As the dyes of natural origin, any of the dyes of plant origin obtained from plants, the dyes of animal origin obtained from insects, and the dyes of mineral origin obtained from minerals can be used, and they may be used in combination. More specifically, the dyes of plant origin include gardenia, madder, indigo, safflower pomegranate, persimmon tannin, onion, etc., the dyes of animal origin include cochineal and lac dye, and the dyes of mineral origin include rock verdigris, lead white, chrome yellow, etc.

[0063] As a method for applying a naturally derived dye to a sheet, it is possible to dye the sheet using a jet dyeing process using a jigger dyeing machine or a jet dyeing machine, a dip dyeing process such as a thermosol dyeing process using a continuous dyeing machine, etc. Among these, it is preferable to use a jet dyeing machine because it is easy to control the temperature and a soft texture can be obtained.

[0064] It is preferable to dye the sheet under conditions where the concentration of the naturally derived dye in the dye solution during dyeing is 2% owf or more and 50% owf or less (the "owf" in % owf is an abbreviation for "on the weight of fiber," and 100% owf indicates that 100% by mass of dye is used relative to the mass of the item to be dyed). By setting the naturally derived dye concentration to 2% owf or more, it becomes possible to dye the artificial leather with naturally derived dye. Also, by setting the naturally derived dye concentration to 50% owf, the amount of dye waste can be reduced, resulting in environmentally friendly artificial leather.

[0065] When dyeing a sheet with a naturally derived dye, the maximum temperature of the dyeing solution in the dye bath is 100° C. or higher and 130° C. or lower. By setting the maximum temperature of the dyeing solution in the dye bath to 100° C. or higher, preferably 102° C. or higher, and more preferably 105° C. or higher, the naturally derived dye penetrates into the polyester fibers, preventing discoloration / fading during washing and discoloration / fading during light resistance. In addition, by setting the maximum temperature of the dyeing solution to 130° C. or lower, preferably 128° C. or lower, and more preferably 125° C. or lower, decomposition of the polymeric elastomer in the sheet can be prevented, and strength as artificial leather can be ensured.

[0066] In the method for producing an artificial leather of the present invention, it is preferable to add a cationic compound before dyeing and / or in the same bath as dyeing. The cationic compound referred to here is the above-mentioned cationic compound. In this way, the cationic compound adheres to the surface of the artificial leather, which can prevent the dye from falling off during washing and suppress discoloration of the artificial leather during washing.

[0067] In this case, the concentration of the cationic compound is preferably 0.05% owf or more and 10% owf or less, regardless of whether it is before dyeing and / or in the same bath as dyeing. By setting the concentration of the cationic compound to 0.05% owf or more, the cationic compound adheres to the artificial leather surface, and the dye can be prevented from falling off during washing. In addition, by setting the concentration of the cationic compound to 10% owf or less, the cationic compound itself does not discolor due to light, and light fastness can be ensured.

[0068] In the method for producing the artificial leather of the present invention, it is preferable to apply an ultraviolet absorbing agent to the polyester fiber before dyeing and / or in the same bath as the dyeing. The ultraviolet absorbing agent referred to here is the ultraviolet absorbing agent described above. By doing so, it is possible to suppress the decomposition of the natural dye contained in the polyester fiber by ultraviolet light and improve the light fastness. In this case, the concentration of the ultraviolet absorber is preferably 2% owf or more and 20% owf or less. By making the concentration of the ultraviolet absorber 2% owf or more, it is possible to prevent the decomposition of the dye during ultraviolet irradiation and ensure light fastness. In addition, by making the concentration of the ultraviolet absorber 20% owf or less, it is possible to reduce the amount of ultraviolet absorber that is not completely absorbed and is discarded.

[0069] (c) Other processes Furthermore, in the method for producing an artificial leather of the present invention, if necessary, the artificial leather can be subjected to post-processing such as finishing treatment, such as adding a finishing agent such as a softener or an antistatic agent after dyeing, hole-making such as perforation, embossing, laser processing, Pinsonic processing, and printing.

[0070] [Miscellaneous goods, accessories, clothing] As described above, the artificial leather of the present invention is characterized by excellent fastness to washing and light, and therefore, the artificial leather can be used as a part of miscellaneous goods, small items, or clothing. Specifically, miscellaneous goods include "bags, shoes, hats," small items include "wallets, pouches," and clothing include "jackets, pants, coats." EXAMPLES

[0071] The present invention will now be described in detail with reference to examples, although the present invention is not limited to these examples.

[0072] [Measurement method] The evaluation methods and measurement conditions used in the examples are described below. Unless otherwise specified, the measurements of each physical property were performed according to the above-mentioned methods. (1) Average single fiber diameter of polyester fibers (μm): The scanning electron microscope (SEM) used was a VHX-D500 / D510 model manufactured by Keyence Corporation, and measurements and calculations were performed according to the above-mentioned methods. (2) Proportion of naturally derived dyes in all dyes (mass%): Measurements and calculations were performed using an accelerator mass spectrometer (AMS) according to the above-mentioned method. (3) Washing fastness (discoloration / staining), light fastness (grade): The washing fastness (discoloration / staining) and light fastness of the artificial leather were evaluated by the above-mentioned methods.

[0073] (4)Environmental friendliness of artificial leather: The dyes were rated on the following three-level scale according to the proportion of naturally derived dyes in the dyes. The good level of the present invention was rated as "◯". · ◯: The proportion of naturally derived dyes in the dye is 98% by mass or more and 100% by mass or less. △: The proportion of naturally derived dyes in the dye is 80% by mass or more and 97% by mass or less. · ×: The proportion of naturally derived dyes in the dye is 0% by mass or more and 79% by mass or less.

[0074] [Example 1] (a) forming a sheet An islands-in-sea type composite fiber having an islands-in-sea type composite structure consisting of island parts and sea parts was melt spun under the following conditions. Island component: Polyethylene terephthalate A with an intrinsic viscosity (IV value) of 0.73 Sea component: Polystyrene with MFR (Melt Flow Rate, measured according to the test method specified in ISO 1133:1997) of 65g / 10min Spinneret: Spinneret for islands-in-sea composite fiber with 16 islands / hole Spinning temperature: 285℃ ·Island component / sea component mass ratio: 55 / 45 Discharge rate: 1.0g / min. / hole Spinning speed: 1100m / min Next, the islands-in-the-sea type composite fiber was stretched 3.4 times in a spinning oil bath at 90°C. The islands-in-sea composite fiber obtained above was subjected to a crimping process using a push-in crimper, and then cut to a length of 51 mm to form an islands-in-sea composite fiber web having a single fiber fineness of 3.2 dtex. The average single fiber diameter of the polyester fibers obtained from this islands-in-sea composite fiber was 2.0 μm.

[0075] The islands-in-the-sea composite fiber web obtained as described above was used to form a laminated web (nonwoven fabric) through carding and cross-wrapping processes, and then a plain weave fabric (weight 50 g / m2) with a weaving density of 67 warp threads / 2.54 cm and 83 weft threads / 2.54 cm was produced using multifilaments (warp thread: average single fiber diameter: 11.0 μm, total fineness: 84 dtex, 72 filaments, twisted yarn with a twist of 2500 T / m, weft thread: average single fiber diameter: 28 μm, total fineness: 56 dtex, 12 filaments, twisted yarn with a twist of 1500 T / m) made of polyethylene terephthalate with an intrinsic viscosity (IV value) of 0.65. 2 ) (woven or knitted fabric) was laminated on the top and bottom of the laminated web (nonwoven fabric). 2 The fabric is needle punched with the number of punches, and the basis weight is 560g / m 2 Thus, a fiber-entangled body having a thickness of 2.3 mm was obtained. The fiber entanglement obtained as described above was shrunk with hot water at 96°C. The fiber entanglement shrunk with hot water was then impregnated with an aqueous solution of polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) with a saponification degree of 88% and adjusted to a concentration of 5% by mass. The fiber entanglement was then squeezed with a roll and dried with hot air at a temperature of 125°C for 10 minutes while migrating the PVA, to obtain a fiber entanglement with PVA such that the mass ratio of PVA to the mass of the fiber entanglement was 27% by mass. The fiber entanglement with PVA obtained in this manner was immersed in trichloroethylene, and the process of squeezing and compressing with a mangle was performed 10 times. In this way, the sea component was dissolved and removed (sea removal) and the fiber entanglement with PVA was compressed, to obtain a fiber entanglement with PVA in which ultrafine fiber bundles were entangled.

[0076] The fiber-entangled body with PVA obtained by entangling ultrafine fiber bundles as described above was immersed in a dimethylformamide (hereinafter sometimes abbreviated as DMF) solution of polyurethane, which was prepared so that the concentration of solids mainly composed of polyurethane was 11.3% by mass. Then, the fiber-entangled body with PVA immersed in the DMF solution of polyurethane was squeezed with a roll. Next, this fiber-entangled body with PVA was immersed in an aqueous DMF solution with a concentration of 30% by mass to coagulate the polyurethane. Then, the PVA and DMF were removed with hot water, and the fiber-entangled body was impregnated with a silicone oil emulsion liquid adjusted to a concentration of 1% by mass, and a silicone-based lubricant was applied so that the amount applied was 0.5% by mass relative to the total mass of the fiber-entangled body and the polyurethane, and the fiber-entangled body was dried for 10 minutes with hot air at a temperature of 120°C. As a result, a sheet with a thickness of 1.3 mm and a polyurethane mass of 20% by mass relative to the mass of the fiber-entangled body was obtained. The sheet obtained as described above was cut into halves so that each half had a thickness of 1 / 2. Next, the surface layer of the cut surface (the surface formed when cut into halves) of the cut sheet was ground by 0.15 mm using endless sandpaper with a sandpaper size of 240 to obtain a napped sheet with a thickness of 0.50 mm.

[0077] (b) Dyeing the napped sheet The napped sheet obtained as described above was dyed for 45 minutes using a liquid jet dyeing machine at the maximum temperature of the dyeing solution in the dye bath of 120°C. When dyeing the napped sheet, the dyeing was performed under conditions containing 20% ​​owf of gardenia, a naturally derived dye, 6% owf of polyamine-type cationic polymer ("Senkafix E-300" manufactured by Senka Corporation) as a cationic compound, and 5% owf of triazine-based ultraviolet absorber ("Tinuvin400" manufactured by BASF) as an ultraviolet absorber. After that, it was dried at 100°C for 7 minutes, and the polyester-based fiber had an average single fiber diameter of 2.0 μm and a basis weight of 220 g / m 2 A dyed artificial leather having a thickness of 0.55 mm was obtained. The results are shown in Table 1. The artificial leather obtained was excellent in environmental friendliness since the proportion of naturally derived dyes in the dye was 100% by mass, and had excellent fastness to washing and light.

[0078] [Example 2] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) of Example 1, dyeing was performed without using a cationic compound. The results are shown in Table 1. The obtained artificial leather was excellent in environmental friendliness and had good fastness to washing and excellent fastness to light.

[0079] [Example 3] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) of Example 1, dyeing was performed without using an ultraviolet absorber. The results are shown in Table 1. The obtained artificial leather was excellent in environmental friendliness and had excellent fastness to washing and good fastness to light.

[0080] [Example 4] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) of Example 1, dyeing was performed without using a cationic compound and an ultraviolet absorber. The results are shown in Table 1. The obtained artificial leather was excellent in environmental friendliness and had good fastness to washing and fastness to light.

[0081] [Example 5] In the step of dyeing the napped sheet (b) of Example 1, 0.25% owf of a polyamine cationic polymer (Senkafix E-300 manufactured by Senka Co., Ltd.) was added as a cationic compound before dyeing, and then dyeing was performed under conditions containing 20% ​​owf of lac dye, which is a naturally derived dye, and 5% owf of a triazine-based ultraviolet absorber (Tinuvin 400 manufactured by BASF) as an ultraviolet absorber. An artificial leather was obtained in the same manner as in Example 1. The results are shown in Table 1. The obtained artificial leather was environmentally friendly and had good fastness to washing and good fastness to light.

[0082] [Table 1]

[0083] [Example 6] An artificial leather was obtained in the same manner as in Example 5, except that in the step of dyeing the napped sheet (b) of Example 5, dyeing was performed without using an ultraviolet absorber. The results are shown in Table 2. The obtained artificial leather was excellent in environmental friendliness and had good fastness to washing and fastness to light.

[0084] [Example 7] An artificial leather was obtained in the same manner as in Example 1, except that in the (a) sheet-forming step of Example 1, raw cotton adjusted so that the average single fiber diameter of the polyester-based fibers was 3.8 μm was used, no woven or knitted fabric was laminated on the top and bottom of the laminated web (nonwoven fabric), and the mass ratio of polyurethane in the product was 35 mass%. The results are shown in Table 2. The obtained artificial leather was environmentally friendly and had excellent fastness to washing and excellent fastness to light.

[0085] [Example 8] (a) forming a sheet-like material An islands-in-sea type composite fiber having a single fiber fineness of 3.5 dtex and having an islands-in-sea type composite structure consisting of island parts and sea parts was melt spun under the following conditions. Island component: Polyethylene terephthalate A with an intrinsic viscosity (IV value) of 0.73 Sea component: Polyethylene terephthalate copolymerized with 9 mol% sodium 5-sulfoisophthalate Spinneret: Spinneret for islands-in-sea composite fiber with 24 islands / hole Spinning temperature: 285℃ ·Island component / sea component mass ratio: 70 / 30 Next, this islands-in-sea type composite fiber was cut to a length of 5 mm and then immersed in a 10 g / L aqueous sodium hydroxide solution heated to 95°C for 30 minutes, thereby obtaining polyethylene terephthalate fiber with a single fiber fineness of 4.0 μm from which the sea component of the islands-in-sea type fiber had been removed. The polyethylene terephthalate fibers obtained as described above were dispersed in water and subjected to a papermaking process to obtain a fiber having a basis weight of 100 g / m 2 A sheet having a basis weight of 50 g / m was produced and used as the surface fiber layer. 2 A plain weave fabric made of multifilaments (average single fiber diameter: 20.0 μm, total fineness: 82 dtex, 36 filaments) made of polyethylene terephthalate with an intrinsic viscosity (IV value) of 0.65 was inserted between the front and back fiber layers to form a three-layer laminated nonwoven fabric sheet. Next, a three-dimensional entangled structure was obtained by spraying a high-speed water stream. The high-speed water stream was sprayed from a straight-flow nozzle with a hole diameter of 0.15 mm at a pressure of 4.0 MPa from the surface fiber layer side and 3.0 MPa from the back fiber layer side to obtain a three-dimensional entangled structure of the surface fiber layer / plain weave fabric / back fiber layer with a basis weight of 200 g / m 2 The surface fiber layer side of this sheet-like material was ground with endless sandpaper with a grit size of 400. Next, the raised sheet-like material was impregnated with a liquid in which 3% by mass of sodium sulfate was added to 9% by mass of a polyether-based water-dispersed urethane, to obtain a napped sheet.

[0086] (b) Dyeing the napped sheet The napped sheet obtained as described above was dyed using a liquid jet dyeing machine at the maximum temperature of the dyeing solution in the dye bath of 120°C. When dyeing the napped sheet, the dyeing was performed under conditions containing 20% ​​owf of gardenia, a naturally derived dye, 6% owf of polyamine-type cationic polymer ("Senkafix E-300" manufactured by Senka Corporation) as a cationic compound, and 5% owf of triazine-based ultraviolet absorber ("Tinuvin400" manufactured by BASF) as an ultraviolet absorber. After that, it was dried at 100°C for 7 minutes, and the polyester-based fiber had an average single fiber diameter of 4.0 μm and a basis weight of 220 g / m 2 A dyed artificial leather having a thickness of 0.95 mm was obtained. The results are shown in Table 2. The obtained artificial leather was environmentally friendly and had excellent fastness to washing and light.

[0087] [Example 9] An artificial leather was obtained in the same manner as in Example 1, except that in the (a) sheet-forming step of Example 1, raw cotton adjusted so that the average single fiber diameter of the polyester-based fibers was 3.8 μm was used, no woven or knitted fabric was laminated on the top and bottom of the laminated web (nonwoven fabric), and the mass ratio of polyurethane in the product was 55 mass%. The results are shown in Table 2. The obtained artificial leather was environmentally friendly and had good fastness to washing and excellent fastness to light.

[0088] [Table 2]

[0089] [Comparative Example 1] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) in Example 1, a cationic compound and an ultraviolet absorber were not used, a woven or knitted fabric was not laminated on the top or bottom of the laminated web (nonwoven fabric), and the maximum temperature of the dyeing solution was set to 80° C. The results are shown in Table 3. The obtained artificial leather was environmentally friendly, but was poor in fastness to washing (discoloration) and fastness to light because the maximum temperature of the dyeing solution was low.

[0090] [Comparative Example 2] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) of Example 1, the maximum temperature of the dyeing solution was set to 80° C. The results are shown in Table 3. The artificial leather obtained was environmentally friendly, but had poor fastness to washing (discoloration) and fastness to light because the maximum temperature of the dyeing solution was low.

[0091] [Comparative Example 3] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) of Example 1, the maximum temperature of the dyeing solution was set to 150° C. The results are shown in Table 3. The obtained artificial leather was excellent in environmental friendliness, but the polyurethane decomposed due to the high maximum temperature of the dyeing solution, and broke during the measurement of washing fastness, making it inferior as an artificial leather.

[0092] [Comparative Example 4] An artificial leather was obtained in the same manner as in Example 1, except that in the (a) step of forming a sheet-like material in Example 1, raw cotton adjusted so that the average single fiber diameter of the polyester-based fibers was 4.4 μm was used, woven or knitted fabrics were not laminated on the top and bottom of the laminated web (nonwoven fabric), and impregnation with polyurethane was not performed. The results are shown in Table 3. The obtained artificial leather was environmentally friendly, but because it did not contain polyurethane, it broke when washing fastness was measured, and was therefore inferior as an artificial leather.

[0093] [Comparative Example 5] An artificial leather was obtained in the same manner as in Example 1, except that in the step of dyeing the napped sheet (b) in Example 1, the natural dye, gardenia, was used at 10% owf and the synthetic dye, disperse dye, was used at 10% owf. The results are shown in Table 3. The artificial leather obtained had excellent fastness to washing (discoloration) and fastness to light due to the presence of the synthetic dye, but the artificial leather lacked environmental consideration.

[0094] [Table 3]

[0095] As shown in Tables 1 and 2, the artificial leathers of Examples 1 to 9 have a specific range of naturally derived dyes in the dyes and the dyes are contained in polyester fibers, making them environmentally friendly and achieving excellent wash fastness and light fastness. On the other hand, as shown in Table 3, when the artificial leathers of Comparative Examples 1 to 5 had a structure in which the dye was not contained in the polyester fiber or did not have a polymer elastomer, it was difficult to achieve both environmental friendliness and washing fastness and light fastness.

Claims

1. An artificial leather comprising a fiber entanglement body containing, as a component, a nonwoven fabric made of dye-containing polyester fibers, and a polymer elastomer, wherein the proportion of naturally derived dye in the dye is 98% by mass or more and 100% by mass or less, and the artificial leather has a washing fastness (discoloration) of grade 3 or more as defined by AATCC-61-2006 1-A method, and a light fastness of grade 3 or more as defined by JIS L0842:2021.

2. The artificial leather of claim 1 , wherein the artificial leather comprises a cationic compound.

3. The artificial leather according to claim 1 or 2, wherein the polyester fiber further contains an ultraviolet absorbing agent.

4. 3. The artificial leather according to claim 1 or 2, wherein the fiber-entangled body further comprises a woven or knitted fabric as a component.

5. 3. The artificial leather according to claim 1, wherein the mass ratio of the polymeric elastomer to the artificial leather is 2 mass % or more and 50 mass % or less.

6. 3. The artificial leather according to claim 1, wherein the polyester-based fibers have an average single fiber diameter of 1.0 μm or more and 10.0 μm or less.

7. A method for producing an artificial leather, comprising dyeing a sheet containing a fiber-entangled body containing a nonwoven fabric made of polyester-based fibers as a component and a polymer elastomer using a dye blend in which the ratio of naturally derived dyes to the total dye is 98% by mass or more and 100% by mass or less, and under conditions in which the maximum temperature of the dye solution in the dye bath is 100° C. or more and 130° C. or less, to obtain an artificial leather having a washing fastness (discoloration) of grade 3 or more as defined by AATCC-61-2006 1-A method and a light fastness of grade 3 or more as defined by JIS L0842:2021.

8. The method for producing an artificial leather according to claim 7, wherein a cationic compound is applied to the sheet before the dyeing and / or in the same bath as the dyeing.

9. The method for producing an artificial leather according to claim 7 or 8, wherein an ultraviolet absorbing agent is applied to the sheet before the dyeing and / or in the same bath as the dyeing.

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