JP7367371B2 - Artificial leather and its manufacturing method - Google Patents

Description

The present invention consists of a fiber entangled body made by blending ultrafine fibers containing black pigment and ultrafine fibers not containing black pigment, and a polymeric elastic body, and has a uniform surface hue in dyeing colors from light to dark. The present invention relates to an artificial leather having a good texture and excellent light resistance, and a method for producing the same.

BACKGROUND OF THE INVENTION Artificial leather that resembles natural leather and is composed of a fiber entanglement mainly made of a thermoplastic resin and an elastic polymer has superior characteristics compared to natural leather, such as high durability and uniform quality. Therefore, it is used not only as a material for clothing, but also in various fields such as vehicle interior materials, interiors, shoes, and clothing. In particular, when artificial leather is used for vehicle interior materials, etc., it is required to have excellent color development and high light resistance that can withstand actual use.

However, it is known that as the fiber diameter of the ultrafine fibers becomes smaller, the specific surface area of the ultrafine fibers increases, making it difficult to dye them in deep colors and resulting in poor color development. On the other hand, attempts are sometimes made to dye the dye by increasing the concentration of the dye in order to produce a deep color, but in that case, the amount of dye used increases, which increases the cost and also reduces the quality of artificial leather. Fastness such as light fastness and abrasion fastness deteriorates. Therefore, a method of adding a black pigment such as carbon black to ultrafine fibers, a method of using so-called spun-dyed fibers, has been proposed. On the other hand, in the above method, spun-dyed fibers of each hue are required in order to correspond to hues such as light colors or intermediate colors between light colors and dark colors.

In order to solve the above problems, in artificial leather using ultra-fine fibers, as a means to achieve both light color or intermediate color between light color and dark color and fastness, we have developed a method of combining dyed fibers with pigments such as carbon black added to ultra-fine fibers and non-dyed fibers. A method of blending spun-dyed fibers has been proposed (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2018-178297

In the technology disclosed in Patent Document 1, two or more hues are produced by uniformly dispersing spun-dyed fibers in which pigments are added to ultrafine fibers and non-spun dyed fibers in water using a papermaking method to form a sheet. Even if the fibers are used, it appears to have substantially one hue, and it is possible to achieve a uniform surface hue. Further, by arbitrarily changing the mixing ratio of spun-dyed fibers and non-spun-dyed fibers constituting the sheet-like material, it is possible to develop colors from gray to black. However, in the papermaking method, it is difficult to provide bulkiness to the sheet, and as a result, it tends to be difficult to attach the elastic polymer to the sheet. As a result, there is a problem that the elasticity of the artificial leather decreases, resulting in the artificial leather having a hard, paper-like texture.

The present invention has been made in view of the above circumstances, and its purpose is to improve dyeing colors from light to dark colors in artificial leather made of a fiber entangled body made of a thermoplastic resin and a polymeric elastomer. An object of the present invention is to provide an artificial leather having a uniform surface hue, a good texture, and excellent light resistance, and a method for producing the same.

As a result of repeated studies by the present inventors in order to achieve the above object, it was found that a fiber entanglement consisting of ultrafine fibers containing a black pigment and ultrafine fibers not containing a black pigment was combined with a polymeric elastomer at a specific mass ratio. It has been found that by adding this, it is possible to create artificial leather that has a uniform surface hue and good texture in dyed colors ranging from light to dark, and also has excellent light resistance.

The present invention has been completed based on these findings, and according to the present invention, the following inventions are provided.

That is, the artificial leather of the present invention is made of a polyester resin, and is made of ultrafine fibers A having an average single fiber diameter of 1.0 μm or more and 6.0 μm or less, and a polyester resin , and has an average single fiber diameter of 1.0 μm or more and 6.0 μm or less. An artificial leather comprising a fiber entangled body consisting of ultrafine fibers B having a diameter of 0 μm or more and 6.0 μm or less, and a polymeric elastomer containing a black pigment, which satisfies all of the following requirements 1 to 5 .
Requirement 1: The ultrafine fiber A contains a black pigment, and the content of the black pigment is 0.01% by mass or more and 1.0% by mass or less based on the mass of the ultrafine fiber A.
Requirement 2: The mass ratio of the ultrafine fibers A in the fiber entangled body is 10% by mass or more and 90% by mass or less.Requirement 3: The variation in the occupation rate of the ultrafine fibers B on the surface of the fiber entangled body is 10% or less. is
Requirement 4: The L ^* value of the surface of the fiber entangled body is 25 or more and 80 or less.
Requirement 5 : The mass ratio of the polymeric elastomer in the artificial leather is 15% by mass or more and 50% by mass or less. According to a preferred embodiment of the artificial leather of the present invention, the black pigment contained in the polymeric elastomer is The content is 0.01% by mass or more and 2.0% by mass or less.

According to a preferred embodiment of the artificial leather of the present invention, the black pigment meeting requirement 1 above is carbon black.

According to a preferred embodiment of the artificial leather of the present invention, the black pigment contained in the polymeric elastomer is carbon black.

The method for producing artificial leather in the present invention includes the following steps (1) to (4).
Step (1): Ultrafine fiber developed fiber A ₀ with a fiber length of 25 mm or more and 90 mm or less, and microfine fiber developed fiber B ₀ with a fiber length of 25 mm or more and 90 mm or less, are mixed so that the mass ratio of the ultrafine fiber developed fiber A ₀ is 10 Step (2) of manufacturing a fiber entangled body by opening the blended raw cotton so as to have a content of not less than 90% by mass and then needle punching: the ultrafine fiber-expressing fiber A ₀ and the Ultrafine fiber-expressing fiber B ₀ is made of ultrafine fiber A with an average single fiber diameter of 1.0 μm or more and 6.0 μm or less, and a polyester resin, and the average single fiber diameter is 1.0 μm or more. Process for developing ultrafine fibers B having a diameter of 6.0 μm or less Step (3): Adding a polymeric elastic body containing a black pigment to the mass of the artificial leather in an amount of 15% by mass or more and 50% by mass or less, Obtaining a sheet-like product Step (4): Raising and dyeing the sheet-like product According to a preferred embodiment of the method for producing artificial leather of the present invention, the ultrafine fiber-expressing fiber A ₀ and The ultrafine fiber development type fiber _B0 has crimps.

According to the artificial leather of the present invention, since the fiber entanglement consisting of the ultrafine fibers containing a black pigment and the ultrafine fibers not containing a black pigment is provided with a polymer elastic body at a specific mass ratio, the color changes from pale to light. It has a uniform surface hue in dyed colors up to deep colors, a soft and good texture, and also has excellent light resistance because it contains a specific proportion of ultrafine fibers containing black pigment. It is possible to obtain artificial leather. The artificial leather of the present invention can be used in a wide range of applications, from furniture, chairs and vehicle interior materials to clothing, but as described above, it has a uniform surface hue and good texture, and has excellent light resistance, so it is especially useful. It can be suitably used for vehicle interior materials.

The artificial leather of the present invention is made of a polyester resin, and is made of ultrafine fibers A having an average single fiber diameter of 1.0 μm or more and 6.0 μm or less, and a polyester resin , and has an average single fiber diameter of 1.0 μm or more. An artificial leather comprising a fiber entangled body consisting of ultrafine fibers B having a diameter of 6.0 μm or less , and a polymer elastic body containing a black pigment, which satisfies all of the following requirements 1 to 5 .
Requirement 1: The ultrafine fiber A contains a black pigment, and the content of the black pigment is 0.01% by mass or more and 1.0% by mass or less based on the mass of the ultrafine fiber A.
Requirement 2: The mass ratio of the ultrafine fibers A in the fiber entangled body is 10% by mass or more and 90% by mass or less.Requirement 3: The variation in the occupation rate of the ultrafine fibers B on the surface of the fiber entangled body is 10% or less. is
Requirement 4: The L ^* value of the surface of the fiber entangled body is 25 or more and 80 or less.
Requirement 5 : The mass ratio of the polymer elastic body in the artificial leather is 15% by mass or more and 50% by mass or less.The constituent elements will be explained in detail below, but the present invention does not exceed the gist thereof. The invention is not limited to the scope described in .

[Fiber entangled body]
In the present invention, the ultrafine fibers A and B constituting the fiber entanglement are made of polyester resin because they have excellent durability, heat resistance, and especially mechanical strength.

Examples of the polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, and polyethylene-1,2- Examples include bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate. Among them, polyethylene terephthalate, which is most commonly used, or a polyester copolymer mainly containing ethylene terephthalate units is preferably used.

The polyester resin used for the ultrafine fiber A and the ultrafine fiber B may contain inorganic particles such as titanium oxide particles, lubricants, heat stabilizers, ultraviolet absorbers, etc., depending on various purposes and within a range that does not impede the purpose of the present invention. agent, conductive agent, heat storage agent, antibacterial agent, etc. can be added.

Furthermore, the ultrafine fiber A contains a black pigment. As this black pigment, carbon-based black pigments such as carbon black and graphite, insulating black pigments such as titanium black, and oxide-based black pigments such as triiron tetroxide and composite oxides of copper and chromium can be used. However, it is preferable to use carbon black because it has a small particle size and can be easily dispersed uniformly.

On the other hand, ultrafine fiber B does not substantially contain black pigment. The phrase "substantially does not contain black pigment" as used herein refers to the use of polyester resin that does not contain black pigment as the raw material for ultrafine fiber B during the production of artificial leather, and the condition of the artificial leather When determining the black pigment content of ultrafine fiber B, if the black pigment is not detected when the content is measured using the method for measuring the black pigment content in ultrafine fibers described below, or if the black pigment content of ultrafine fiber B is It means that the mass proportion in B is 0.001% by mass or less. Since the ultrafine fibers B do not substantially contain black pigment, when the ultrafine fibers A and B are blended together, a color ranging from light to dark can be produced.

The cross-sectional shape of the ultrafine fiber A and the ultrafine fiber B is preferably round from the viewpoint of processing operability; It is also possible to adopt an irregular cross-sectional shape such as a T-shape or a U-shape.

The average single fiber diameter of the ultrafine fibers A and B is preferably 1.0 μm or more and 10.0 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 effects can be achieved in color development after dyeing, light fastness and abrasion fastness, and stability during spinning. On the other hand, by setting the thickness to 10.0 μm or less, preferably 6.0 μm or less, and more preferably 4.5 μm or less, artificial leather with excellent surface quality that is dense and soft to the touch can be obtained.

In the present invention, the average single fiber diameter of the ultrafine fibers shall be calculated by the following method.
(1) Take a scanning electron microscope (SEM) photograph of a cross section of the artificial leather, and randomly select 10 circular or nearly circular elliptical ultrafine fibers.
(2) Measure the single fiber diameter, calculate the arithmetic average value of 10 fibers, and round it to the second decimal place.
(However, if ultrafine fibers with atypical cross sections are used, the diameter of the single fibers shall be determined by first measuring the cross-sectional area of the single fibers and calculating the diameter when the cross section is assumed to be circular. )
Further, the black pigment used in the present invention preferably has an arithmetic average particle diameter of 0.01 μm or more and 0.30 μm or less in the ultrafine fibers.

The particle size here refers to the particle size when the black pigment is present in the ultrafine fibers, and is generally referred to as the secondary particle size.

When the arithmetic mean of the particle diameter is 0.01 μm or more, more preferably 0.05 μm or more, or 0.30 μm or less, more preferably 0.25 μm or less, and even more preferably 0.20 μm or less, color development and spinning It has excellent stability and yarn strength.

In the present invention, the arithmetic mean of particle diameters shall be calculated by the following method.
(1) An ultrathin section with a thickness of 5 to 10 μm is prepared in the cross-sectional direction of the plane perpendicular to the longitudinal direction of the ultrafine fiber.
(2) Observe the cross section of the fiber in the ultrathin section using a transmission electron microscope (TEM) at 10,000 times magnification.
(3) Using image analysis software, measure the circle equivalent diameter of the pigment particle size included in the 2.3 μm x 2.3 μm field of view of the observed image at 20 points.
(4) Calculate the average value (arithmetic mean) of the measured particle diameters at 20 points.

The proportion of the black pigment contained in the ultrafine fibers A is preferably 0.01% by mass or more and 2.0% by mass or less based on the mass of the ultrafine fibers A. By setting the above proportion to 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, artificial leather with excellent color development from light to deep colors can be obtained. be able to. On the other hand, by setting the content to 2.0% by mass or less, more preferably 1.5% by mass or less, it is possible to obtain artificial leather with high physical properties such as yarn strength.

In the present invention, the proportion of black pigment contained in ultrafine fiber A shall be calculated by the following method.
(1) Artificial leather is immersed in a solution containing dimethylformamide, etc., the polymer elastic body is removed, and ultrafine fibers are collected.
(2) Regarding the collected ultrafine fibers, dissolve the polyester component using a mixed solution of phenol and tetrachloroethane, and extract only the black pigment.
(3) Perform a generated gas analysis on the extracted black pigment, and create a calibration curve for the generated gas derived from the black pigment.
(4) After de-dying the artificial leather, extract the polymeric elastomer using dimethylformamide or the like to make only ultrafine fibers, and then collect ultrafine fibers A.
(5) Perform an emitted gas analysis on the collected ultrafine fiber A, and calculate the proportion of black pigment contained in the ultrafine fiber A from the detected intensity of the emitted gas derived from the black pigment and the calibration curve created in (3).

The artificial leather of the present invention has ultrafine fibers in the form of fiber entanglements. By forming the fiber entangled body, a uniform and elegant appearance and texture can be obtained when the surface is brushed.

The forms of fiber entangled bodies include long fiber entangled bodies mainly composed of filaments and short fiber entangled bodies mainly composed of fibers of 100 mm or less. In the case where the base material of the fiber layer constituting the artificial leather is a long fiber entanglement, it is preferable because an artificial leather with excellent strength can be obtained. On the other hand, in the case of a short fiber entanglement, more fibers can be oriented in the thickness direction of the artificial leather than in the case of a long fiber entanglement, and the surface of the artificial leather when raised has a high density. It can make you feel.

It is important that the mass ratio of the ultrafine fibers A in the fiber entangled body of the present invention is 10% by mass or more and 90% by mass or less. By setting the mass ratio of ultrafine fibers A to 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, artificial leather with excellent light fastness can be obtained. On the other hand, by setting the content to 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, it is possible to obtain artificial leather with excellent hue variations in dark colors.

It is important that the variation in the occupancy of the ultrafine fibers B on the surface of the fiber entangled body is 10% or less. By controlling the variation in occupancy to 10% or less, more preferably 7.5% or less, still more preferably 5% or less, a fiber entangled body with a uniform surface hue can be obtained.

In the present invention, it is assumed that the variation in occupancy rate is calculated by the following method.
(1) Randomly take 10 surface images of the fiber entangled body at 100 times magnification using a digital microscope.
(2) Using image analysis software, each captured surface image is binarized, and the occupancy rate of white (corresponding to the location where ultrafine fiber B is present) in the total area is calculated for 10 points.
(3) Find the average value (arithmetic mean) and standard deviation of the calculated occupancy rates of the 10 points, and calculate the variation (CV) of the occupancy rates using the following formula.
・CV=standard deviation/average value×100
Furthermore, the surface brightness (L ^* value) of the fiber entangled body of the present invention can be adjusted by adjusting the mixing ratio of ultrafine fibers A and ultrafine fibers B, and the surface brightness (L ^* value) is preferably 25 or more and 80 or more. By setting the ratio to be more preferably 30 or more and 75 or less, and still more preferably 35 or more and 70 or less, it is possible to develop hues ranging from light to dark. Note that the surface brightness refers to "3.3 CIE1976 brightness index" in JIS Z8781-4:2013 "Color measurement - Part 4: CIE1976L ^* a ^* b ^* color space", with the surface of the fiber entangled body as the measurement surface. It refers to the L ^* value defined by . In the present invention, the L ^* value is measured 10 times using a spectrophotometer, and the arithmetic mean of the measurement results is employed as the L ^* value of the fiber entangled body.

The basis weight of the fiber entangled body constituting the artificial leather according to the present invention is measured according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General nonwoven fabric testing method", and is 50 g/m2 ^or more. It is preferable that it is 400 g/m ² or less. By setting the basis weight of the fiber entangled body to 50 g/m ² or more, more preferably 80 g/m ^{2 or} more, it is possible to obtain artificial leather with a full feeling and excellent texture. On the other hand, by setting it to 400 g/m ² or less, more preferably 300 g/m ² or less, a flexible artificial leather with excellent moldability can be obtained.

[Elastic polymer]
The elastic polymer that constitutes the artificial leather of the present invention is a binder that holds the ultrafine fibers that constitute the artificial leather. , polyurethane, polyurethane, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and acrylic resin. Among these, it is a preferred embodiment to use polyurethane as the main component. By using polyurethane, it is possible to obtain artificial leather that has a solid feel, a leather-like appearance, and physical properties that can withstand practical use. In addition, "being a main component" as used in the present invention means that the mass of polyurethane is more than 50% by mass with respect to the mass of the entire elastic polymer body.

When polyurethane is used in the present invention, either organic solvent-based polyurethane, which is used in a state dissolved in an organic solvent, or water-dispersed polyurethane, which is used in a state where it is dispersed in water, can be employed. Moreover, as the polyurethane, a polyurethane obtained by the reaction of a polymer diol, an organic diisocyanate, and a chain extender is preferably used.

In addition, depending on the purpose, various additives are added to the polymer elastomer, such as pigments such as carbon black, flame retardants such as ``phosphorus-based, halogen-based, and inorganic'', and ``phenol-based, sulfur-based, and phosphorus-based''. Antioxidants such as ``benzotriazole type, benzophenone type, salicylate type, cyanoacrylate type and oxalic acid anilide type'', UV absorbers such as ``hindered amine type and benzoate type'', polycarbodiimide It may contain hydrolysis stabilizers such as, plasticizers, antistatic agents, surfactants, coagulation regulators, dyes, and the like.

In order to achieve excellent light resistance in the present invention, it is preferable that the polymeric elastomer contains a black pigment as a pigment. As the black pigment in the present invention, carbon-based black pigments such as carbon black and graphite, insulating black pigments such as titanium black, oxide-based black pigments such as triiron tetroxide, and composite oxides of copper and chromium may be used. However, it is preferable to use carbon black because it has a small particle size and can be easily dispersed uniformly.

The proportion of the black pigment contained in the elastomer polymer is preferably 0.01% by mass or more and 2.0% by mass or less based on the mass of the elastomer polymer. By setting the above proportion to 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, artificial leather with excellent light resistance can be obtained. On the other hand, by setting the content to 2.0% by mass or less, more preferably 1.5% by mass or less, artificial leather with excellent friction fastness can be obtained.

In the present invention, the proportion of black pigment contained in the elastomer polymer shall be calculated by the following method.
(1) Artificial leather is immersed in a mixture of phenol and tetrachloroethane to dissolve the ultrafine fibers and collect the polymer elastic body.
(2) The collected elastic polymer is made into a solution using dimethylformamide or the like, and only the black pigment is extracted.
(3) Perform gas emission analysis on the extracted black pigment and create a calibration curve for gas generated from the black pigment.
(4) After the elastic polymer contained in the artificial leather is made into a solution using dimethylformamide or the like, the dimethylformamide or the like is removed to solidify the elastic polymer again.
(5) Perform an evolved gas analysis on the polymer elastic body obtained in (4), and from the detected intensity of the generated gas derived from the black pigment and the calibration curve created in (3), the polymer elastic body constituting the artificial leather Calculate the proportion of black pigment contained in

Generally, the content of the elastic polymer in artificial leather can be adjusted as appropriate, taking into account the type of elastic polymer used, the method of manufacturing the elastic polymer, and the texture and physical properties. In this case, it is important that the content of the polymeric elastomer is 15% by mass or more and 50% by mass or less based on the mass of the artificial leather. By setting the content of the elastic polymer to 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, the bond between the fibers by the elastic polymer can be strengthened, The wear resistance of artificial leather can be improved. On the other hand, by setting the content of the polymeric elastomer to 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less, the artificial leather can be made more flexible. can.

[Artificial leather]
In the artificial leather of the present invention, it is a preferable embodiment that the surface has nape. The nap may be present only on the surface of the artificial leather, or it is also acceptable to have it on both sides. In the case where the surface has piloerection, the piloere formation has enough length and directional flexibility to produce so-called finger marks, which leave marks due to changes in the direction of the piloes when traced with a finger from the viewpoint of design effect. It is preferable. More specifically, the nap length on the surface is preferably 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more. On the other hand, if the nap length is too long, the durability of the artificial leather against friction will be reduced, so it is preferably 400 μm or less, and more preferably 350 μm or less. To determine the length of the nap on the surface, take a SEM photo of the cross section of the artificial leather at a magnification of 50x with the nap of the artificial leather standing on end using a lint brush, etc., and measure the height of the nap (layer consisting only of ultra-fine fibers) by 10 points. Calculated by measuring and calculating the average value.

The artificial leather of the present invention has a thickness of 0.2 mm or more as measured by "6.1.1 A method" in "6.1 Thickness (ISO method)" of JIS L1913:2010 "General nonwoven fabric test method". It is preferable that it is 1.2 mm or less. By setting the thickness of the artificial leather to 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.4 mm or more, it not only has excellent processability during manufacturing, but also has a full and excellent texture. It becomes something. On the other hand, by setting the thickness to 1.2 mm or less, more preferably 1.1 mm or less, still more preferably 1.0 mm or less, a flexible artificial leather with excellent moldability can be obtained.

The artificial leather of the present invention has a friction fastness measured by "9.1 Friction tester type I (crockmeter) method" of JIS L0849: 2013 "Dyeing fastness test method against friction" and JIS L0843: 2006 "Xenon It is preferable that the light fastness measured by ``7.2 Exposure method a) 1st exposure method'' of ``Test method for dye fastness to arc lamp light'' is grade 4 or higher. By having a friction fastness and a light fastness of grade 4 or higher, it is possible to prevent discoloration and staining of clothes, etc. during actual use.

In addition, the artificial leather of the present invention has been tested in "8.19.5 E method (Martindale method)" in "8.19 Abrasion strength and friction discoloration" of JIS L1096:2010 "Testing methods for textiles and knitted fabrics". In the measured abrasion resistance test, the press load is 12.0 kPa, and the weight loss of the artificial leather after being worn 20,000 times is preferably 10 mg or less, more preferably 8 mg or less, and 6 mg or less. It is more preferable that When the weight loss is 10 mg or less, contamination due to fluff falling during actual use can be prevented.

[Manufacturing method of artificial leather]
The artificial leather of the present invention is manufactured by including the following steps (1) to (4).
Step (1): Ultrafine fiber developed fiber A ₀ with a fiber length of 25 mm or more and 90 mm or less, and microfine fiber developed fiber B ₀ with a fiber length of 25 mm or more and 90 mm or less, are mixed so that the mass ratio of the ultrafine fiber developed fiber A ₀ is 10 Step (2) of manufacturing a fiber entangled body by opening the blended raw cotton so as to have a content of not less than 90% by mass and then needle punching: the ultrafine fiber-expressing fiber A ₀ and the Step (3) of removing the easily soluble components of ultrafine fiber expression type fiber B ₀ : The content of the polymeric elastic body containing the black pigment is 15% by mass or more and 50% by mass or less based on the mass of the artificial leather. Step (4) of applying and obtaining a sheet-like product: Step of raising and dyeing the sheet-like product The details of each step will be explained below.

<Step 1>
In this step, first, ultrafine fiber expression type fiber A ₀ and ultrafine fiber expression type fiber B ₀ are manufactured. Examples of the ultrafine fiber developed fiber A ₀ and the ultrafine fiber developed fiber B ₀ include sea-island composite fibers and mixed spun composite fibers. Among these, sea-island composite fibers are preferred because ultrafine fibers of 5.0 μm or less can be easily and stably produced.

When using a sea-island composite fiber, an ultrafine fiber-expressing fiber _A0 , which is a sea-island composite fiber, in which the ultrafine fiber A made of a polyester resin containing a black pigment forms the island portion, and the easily soluble polymer forms the sea portion; An ultrafine fiber-expressing fiber _B0 is produced which is a sea-island composite fiber in which the ultrafine fiber B made of a polyester resin containing no black pigment forms the island portion and the easily soluble polymer forms the sea portion.

The ultrafine fiber developed fiber A ₀ and the ultrafine fiber developed fiber B ₀ are sea-island composite fibers in which the sea part (easily soluble polymer) and the island part (slightly soluble polymer) are thermoplastic resins having different solvent solubility. This refers to fibers in which the island portions are made into ultrafine fibers by dissolving and removing the sea portions using a solvent or the like. By using sea-island composite fibers, it is possible to provide appropriate voids between the islands, that is, between the ultrafine fibers inside the fiber bundle when removing the sea areas, which is preferable from the viewpoint of the texture and surface quality of the artificial leather. As a method for spinning sea-island composite fibers, a method using a polymer mutual array in which a sea-island type composite spinneret is used and spun by arranging sea parts and island parts mutually produces ultrafine fibers with uniform single fiber fineness. It is preferable from this point of view. Note that this fiber can be manufactured by a known method.

In this manufacturing process, it is preferable that ultrafine fiber developed fiber A ₀ and ultrafine fiber developed fiber B ₀ be crimped by crimping after stretching.

The proportion of the black pigment contained in _the island component of the microfiber-expressing fiber A ₀ is determined in order to achieve both the color development of the artificial leather and the suppression of the decrease in yarn strength of the micro-fine fiber. It is preferably 0.01% by mass or more and 2.0% by mass or less based on the mass. Even when the ultrafine fiber developed fiber A ₀ is not a sea-island composite fiber, the amount should be 0.01% by mass or more and 2.0% by mass or less based on the mass of the hardly soluble polymer that constitutes the microfiber developed fiber A ₀ . It is preferable.

As a method for incorporating a black pigment into the hardly soluble polymer constituting the ultrafine fiber development type fiber, it is possible to incorporate the black pigment into the polyester resin by spinning using only chips in which the black pigment has been kneaded with the polyester resin in advance. Any of the methods of mixing a masterbatch kneaded with a black pigment and the above-mentioned polyester resin chips and spinning the mixture can be adopted. Among these, the method of mixing with polyester resin chips using a masterbatch is preferred because the amount of pigment contained in the ultrafine fibers can be adjusted as appropriate.

As the easily soluble polymer for the ultrafine fiber development type fiber, polyethylene, polypropylene, polystyrene, copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, etc., and polylactic acid can be used. Among these, polystyrene and copolymerized polyester are preferably used because they are difficult to break and can easily elute the polymer. Various additives such as inorganic particles such as titanium oxide particles, lubricants, heat stabilizers, ultraviolet absorbers, and antibacterial agents can be added to these resins depending on the desired properties.

In the method for producing artificial leather of the present invention, when ultrafine fiber-expressing fibers are used, it is preferable to use ultrafine fiber-expressing fibers whose hardly soluble polymer has a strength of 2.5 cN/dtex or more. When the strength of the hardly soluble polymer is 2.5 cN/dtex or more, more preferably 2.8 cN/dtex or more, and still more preferably 3.0 cN/dtex or more, the abrasion resistance of the artificial leather can be improved. .

In the present invention, the strength of the hardly soluble polymer constituting the microfiber-expressing fiber is calculated by the following method.
(1) Bundle 10 ultrafine fiber expression type fibers with a length of 20 cm.
(2) After dissolving and removing the easily soluble polymer from the sample in (1), air dry it.
(3) JIS L1013:2010 "Chemical fiber filament yarn test method""8.5 Tensile strength and elongation rate""8.5.1 Standard time test", grip length 5 cm, tensile speed 5 cm/min , the test is carried out 10 times under the condition of a load of 2N (N=10).
(4) The arithmetic mean value (cN/dtex) of the test results obtained in (3) is rounded to the second decimal place and the value obtained is calculated as the strength of the hardly soluble polymer constituting the microfiber-expressing fiber. shall be.

Further, the fiber length of the ultrafine fiber-expressing fiber after crimping is preferably 25 mm or more and 90 mm or less. By setting the fiber length to 90 mm or less, more preferably 80 mm or less, and still more preferably 70 mm or less, good quality and texture can be achieved. On the other hand, by setting the fiber length to 25 mm or more, more preferably 35 mm or more, and still more preferably 40 mm or more, artificial leather with excellent abrasion resistance can be obtained.

In the present invention, the fiber length of the ultrafine fiber-expressing fiber that is not crimped or that has been crimped is calculated by the following method.
(1) Collect 10 microfiber-expressing fibers after cutting.
(2) Using a measuring instrument such as a ruler, measure the length of the 10 collected microfiber-expressing fibers (N = 10) if they are not crimped, or if they are crimped. A load of 1 cN is applied to the collected 10 ultrafine fiber-expressing fibers in the longitudinal direction of the ultra-fine fiber-expressing fibers, and then the length is measured (N=10).
(3) The value obtained by rounding off the arithmetic mean value (mm) of the measurement results obtained in (2) to the first decimal place is defined as the fiber length of the microfiber-expressing fiber.

In this step, after spinning, stretching, and crimping, ultrafine fiber developed fiber A ₀ and ultrafine fiber developed fiber B ₀ cut into fiber lengths of 25 mm or more and 90 mm or less are blended. As a method for blending the ultrafine fiber expression type fiber A ₀ and the ultrafine fiber expression type fiber B ₀ , a cotton blending machine having a rotary body having plate-shaped, blade-shaped, or pin-shaped protrusions, an air blender, etc. can be used. .
By blending after shortening the fibers, it is possible to obtain artificial leather in which ultrafine fibers A and B are uniformly dispersed within the artificial leather, and the surface hue of the fiber entanglement can be made uniform. The mass ratio of ultrafine fiber generation type fibers _A0 in the fiber entangled body is 10% by mass or more and 90% by mass or less in the fiber entangled body.

In this step, the spun ultrafine fiber type expression fibers are blended and opened, and then formed into a fiber web using a cross wrapper or the like, and entangled to obtain a fiber entangled body. As a method for entangling fiber webs to obtain a fiber entangled body, needle punching, water jet punching, or the like can be used.

As mentioned above, the form of the fiber entanglement can be either a short fiber entanglement or a long fiber entanglement, but in the case of a short fiber entanglement, the fibers oriented in the thickness direction of the artificial leather are long fiber entanglement. This increases the number of strands compared to , and it is possible to obtain a highly dense texture on the surface of artificial leather when brushed.

The variation in the occupancy of ultrafine fiber type fibers B ₀ on the surface of the fiber entangled body made of ultrafine fiber type fibers after needle punching or water jet punching is 10% or less.

Further, the apparent density of the fiber entangled body is preferably 0.15 g/cm ³ or more and 0.45 g/cm ³ or less. By setting the apparent density to preferably 0.15 g/cm ³ or more, the artificial leather can have sufficient morphological stability and dimensional stability. On the other hand, by setting the apparent density to preferably 0.45 g/cm ³ or less, sufficient space for providing the polymer elastic body can be maintained.

In the present invention, the apparent density of the fiber entangled body shall be calculated by the following method.
(1) Measure the processed weight (kg), processed length (m), processed width (m), and thickness (mm) of the fiber entangled body after needle punching.
(2) The apparent density (g/cm ³ ) of the fiber entangled body is calculated from the measured processed weight, processed length, processed width, and thickness of the fiber entangled body using the following formula.
・Apparent density (g/ ^cm3 ) = Processing weight (kg)/(Processing length (m) x Processing width (m) x Thickness (mm))
It is also a preferable embodiment to subject the fiber entangled body to a heat shrinkage treatment using hot water or steam in order to improve the denseness of the fibers.

Next, a water-soluble resin can be applied by impregnating the fiber entangled body with an aqueous solution of a water-soluble resin and drying it. By adding a water-soluble resin to the fiber entangled body, the fibers are fixed and dimensional stability is improved.

<Step 2>
In this step, the obtained fiber entanglement is treated with a solvent, and the average single fiber diameter of the single fibers is 1.0 μm or more from the ultrafine fiber development type fiber A ₀ and the ultrafine fiber development type fiber B ₀ . Develops ultrafine fibers of 0 μm or less.

The ultrafine fiber development treatment can be carried out by immersing a fiber entangled body made of microfine fiber development type fibers in a solvent and dissolving and removing the easily soluble polymer of the microfine fiber development type fibers.

As the solvent for dissolving and removing the easily soluble polymer, when the easily soluble polymer is polyethylene, polypropylene, or polystyrene, an organic solvent such as toluene or trichloroethylene can be used. Furthermore, when the easily soluble polymer is copolymerized polyester or polylactic acid, an alkaline aqueous solution such as sodium hydroxide can be used. Moreover, when the easily soluble polymer is a water-soluble thermoplastic polyvinyl alcohol resin, hot water can be used.

<Step 3>
In this process, after impregnating a fiber entangled body mainly composed of ultrafine fibers or ultrafine fiber-expressing fibers with a solution of a polymeric elastic material and solidifying it, a polymeric elastic material containing a black pigment is added to the mass of the artificial leather. 15% by mass or more and 50% by mass or less. As the polymer elastic body, those mentioned above are preferably used. In addition, methods for fixing the polymeric elastic body to the fiber entangled body include a "wet coagulation method" in which the fiber entangled body is impregnated with a solution of the polymeric elastic body and then fixed by immersing it in a coagulation bath; , "dry coagulation method" which involves drying and fixing, etc., and these methods can be selected as appropriate depending on the type of polymer elastic material used.

As the solvent used when applying polyurethane as the polymeric elastomer, N,N'-dimethylformamide, dimethyl sulfoxide, etc. are preferably used. Alternatively, a water-dispersed polyurethane liquid in which polyurethane is dispersed in water as an emulsion may be used.

The polymer elastic material may be applied to the fiber entanglement before generating ultrafine fibers from ultrafine fiber expression type fibers, or after generating ultrafine fibers from ultrafine fiber expression type fibers. Good too.

<Step 4>
From the viewpoint of improving production efficiency, it is also preferable that the sheet-like product to which the polymeric elastic body is applied after completing Step 3 is cut in half in the thickness direction to form two sheet-like products. It is.

Furthermore, the surface of the sheet-like article provided with the above-mentioned elastic polymer material or the sheet-like material provided with the elastic polymer material cut in half can be subjected to a napping treatment. The raising treatment can be performed by grinding using sandpaper, a roll sander, or the like. The napping treatment can be applied to only one surface of the sheet-like material or to both surfaces.

When performing the napping treatment, a lubricant such as a silicone emulsion can be applied to the surface of the sheet-like article before the napping treatment. Further, by applying an antistatic agent before the napping treatment, grinding powder generated from the sheet material during grinding becomes difficult to accumulate on the sandpaper.

The above-mentioned sheet-like material is preferably dyed with a dye having the same color as the black pigment. Examples of this dyeing process include jet dyeing using a jigger dyeing machine or jet dyeing machine, thermosol dyeing using a continuous dyeing machine, roller printing, screen printing, inkjet printing, and sublimation. Printing treatment on the raised surface by printing, vacuum sublimation printing, etc. can be used. Among these, it is preferable to use a jet dyeing machine from the viewpoint of quality and elegance, since a soft texture can be obtained. Moreover, various resin finishing processes can be applied after dyeing, if necessary.

The surface of the above-mentioned sheet-like product can be provided with a design if necessary. For example, post-processing treatments such as perforation, embossing, laser processing, pinsonic processing, and printing can be performed.

The artificial leather of the present invention obtained by the manufacturing method exemplified above has a uniform surface hue and a flexible texture in dyed colors ranging from light to dark colors, and also has excellent durability. It can be used in a wide range of applications, from chairs and vehicle interior materials to clothing, and is particularly suitable for vehicle interior materials because of its excellent light fastness.

Next, the artificial leather of the present invention will be explained in more detail using Examples, but the present invention is not limited to these Examples. Next, the evaluation method and measurement conditions used in the examples will be explained. However, in the measurement of each physical property, unless otherwise specified, the measurement was performed based on the method described above. In addition, hereinafter, the portions described as "Example 6", including those in Table 1, shall be read as "Reference Example 1".

[Measurement method and processing method for evaluation]
A. Arithmetic mean of pigment particle size:
Ultrathin sections in the cross-sectional direction of the plane perpendicular to the longitudinal direction of the ultrafine fibers were prepared using an ultramicrotome "MT6000 model" manufactured by Sorvall. The obtained sections were observed using a transmission electron microscope ("H7700" manufactured by Hitachi High Technologies). Next, the particle diameter of the pigment was measured using image analysis software ("WinROOF" manufactured by Mitani Corporation).

B. Variation in occupancy:
The surface image of the fiber entangled body was taken using a digital microscope "VHX-950F" manufactured by Keyence Corporation. Next, image analysis software "ImageJ" was used to binarize the captured surface image.

C. Black pigment content:
The proportion of black pigment contained in the ultrafine fiber A and the polymeric elastomer was measured using a generated gas analyzer "GCMS-QP2010" manufactured by SHIMADZU.

D. Lightness of fiber entanglement and artificial leather (L ^* value):
The L ^* value defined in 3.3 of JIS Z8781-4:2013 "Colorimetry - Part 4: CIE1976L ^* a ^* b ^* color space" mentioned above was measured using a spectrophotometric system. The measurement was performed 10 times using a color difference meter "CR-310" manufactured by Konica Minolta, and the average thereof was taken as the L ^* value of the fiber entangled body and the artificial leather.

E. Rub fastness of artificial leather:
The degree of contamination of the sample after measurement is determined using the gray scale for contamination specified in JIS L0805:2005 "Gray scale for contamination", and is graded 4 or higher (L ^* a ^* b ^* color difference ΔE ^* _ab by color system) (4.5±0.3 or less) was considered a pass.

F. Light fastness of artificial leather:
After irradiation, the degree of discoloration and fading of the sample was determined using the gray scale for discoloration and fading specified in JIS L0804:2004 "Gray scale for discoloration and fading", and the grade was determined to be grade 4 or higher (L ^* a ^* b ^* color difference ΔE according to color system) ^* _ab is 1.7±0.3 or less) was considered a pass.

G. Abrasion resistance of artificial leather:
James H. as an abrasion tester. Heal & Co. "Model 406" manufactured by the company was subjected to an abrasion resistance test using the company's "Abrasive CLOTH SM25" as a standard friction cloth, and artificial leathers with an abrasion loss of 10 mg or less were passed.

H. Artificial leather surface uniformity:
A total of 20 evaluators, 10 healthy adult men and 10 adult women, performed visual evaluations as described below, and the most frequently evaluated evaluation was taken as surface uniformity. In addition, in the case of the same number of evaluations, the higher evaluation was given to the uniformity of the surface of the artificial leather. In the present invention, a good level is "A or B".
- A: A very uniform surface hue. - B: A uniform surface hue. - C: A highly uneven surface hue. - D: A very uneven surface hue.

I. Artificial leather texture:
A total of 20 evaluators, 10 healthy adult men and 10 adult women, conducted sensory evaluations as described below, and the most frequently evaluated evaluation was taken as the feel of the artificial leather. In addition, in the case of the same number of evaluations, the texture of the artificial leather was given a higher evaluation. In the present invention, a good level is "A or B".
- A: Soft and good texture. - B: Slightly soft and good texture. - C: Slightly hard and bad texture. - D: Tough and bad texture.

[Example 1]
<Step 1>
Sea-island composite fiber A ₀ (island portion: ultrafine fiber A) and sea-island composite fiber B ₀ (island portion: ultrafine fiber B) having a sea-island composite structure were melt-spun under the following conditions.
[Sea-island composite fiber A ₀ ]
- Island part (ultrafine fiber A): A mixture of the following components (a) and (b) at a mass ratio of 95:5 (a) Polyethylene terephthalate A with an intrinsic viscosity (IV value) of 0.73
(b) A masterbatch/Ama where carbon black (average particle diameter: 0.20 μm) is contained as a black pigment in the polyethylene terephthalate A at 20% by mass based on the mass of the masterbatch: MFR is 65g/10 Polystyrene, nozzle: Sea-island composite nozzle with 16 islands/holes, spinning temperature: 285℃
・Island/Ama mass ratio: 80/20
・Discharge amount: 1.2g/(minute/hole)
- Spinning speed: 1100m/min.
[Sea-island composite fiber B ₀ ]
・Island part (ultrafine fiber B): Polyethylene terephthalate A with an intrinsic viscosity (IV value) of 0.73
・Ama: Polystyrene with MFR of 65 g/10 minutes ・Merch: Sea-island type composite ferrule with 16 islands/holes ・Spinning temperature: 285°C
・Island/Ama mass ratio: 80/20
・Discharge amount: 1.2g/(minute/hole)
- Spinning speed: 1100m/min.

Next, each sea-island composite fiber was stretched 2.7 times in a spinning oil bath at 90°C. After crimping using a push-in type crimper, it was cut into a length of 51 mm to obtain a sea-island composite fiber raw cotton having a single fiber fineness of 3.8 dtex. The average single fiber diameter of the ultrafine fibers obtained from this sea-island composite fiber was 4.4 μm.
The raw cotton obtained as described above was mixed using a cotton blending machine equipped with a rotating body having pin-shaped protrusions so that the ratio of ultrafine fibers A and ultrafine fibers B in the fiber entangled body was 50:50 by mass. I mixed it with cotton.

Using the raw cotton obtained as described above, a laminated web was formed through a carding and cross-wrapping process. Then, needle punching was performed using a punch count of 2500 punches/cm ² to obtain a fiber entangled body having a basis weight of 540 g/m ² and a thickness of 2.4 mm. The occupancy rate of the ultrafine fibers B on the surface of the fiber entangled body was 49%, and the variation in the occupancy rate was 6.2%.

<Step 2>
The fiber entangled body obtained as described above was subjected to a shrinkage treatment with hot water at 96°C. Thereafter, the fiber entangled body subjected to shrinkage treatment with hot water was impregnated with a polyvinyl alcohol (PVA) aqueous solution having a saponification degree of 88% and prepared to have a concentration of 12% by mass. Further, this was squeezed with a roll and dried with hot air at a temperature of 120°C for 10 minutes while migrating the PVA, to obtain a PVA-coated sheet in which the mass of PVA was 25% by mass based on the mass of the sheet base. The PVA-coated sheet thus obtained was immersed in trichlorethylene, and squeezed and compressed using a mangle 10 times. As a result, the sea portion was dissolved and removed, and the PVA-coated sheet was subjected to compression treatment, thereby obtaining a PVA-coated sheet in which ultrafine fiber bundles to which PVA was applied were entangled.

<Step 3>
The PVA-coated sheet obtained as described above is immersed in a DMF (dimethylformamide) solution of polyurethane prepared to have a solid content concentration of 13%, the main component of which is polyurethane containing carbon black as a black pigment. I let it happen. Thereafter, the sea-removed PVA-attached sheet soaked in the polyurethane DMF solution was squeezed with a roll. Next, this sheet was immersed in a DMF aqueous solution having a concentration of 30% by mass to coagulate the polyurethane. Thereafter, PVA and DMF were removed with hot water and dried with hot air at a temperature of 110° C. for 10 minutes. As a result, a polyurethane-coated sheet having a thickness of 1.8 mm, a polyurethane mass of 30% by mass relative to the mass of the fiber entangled body, and a carbon black content of 0.1% by mass in the polyurethane was obtained.

<Step 4>
The polyurethane-coated sheet obtained as described above was cut in half so that each half had a thickness of 1/2. Next, the surface layer on the opposite side of the half-cut surface was ground by 0.3 mm using endless sandpaper with a sandpaper count of 180, and the surface layer was brushed so that the nap length on the surface was 300 μm. A napped sheet was obtained.

The raised sheet obtained as described above was dyed using a jet dyeing machine. At this time, the dyed artificial leather was dyed using a disperse dye at 120°C, so that the artificial leather had a brown color with an L ^* value of 26.5, an a* value of 1.4, and a b* value of 1.0. Using. Thereafter, a drying treatment was performed at 100° C. for 7 minutes to obtain artificial leather having an average single fiber diameter of ultrafine fibers of 4.4 μm, a basis weight of 220 g/m ² , and a thickness of 0.7 mm. The obtained artificial leather had excellent abrasion fastness and light fastness, and also had abrasion resistance. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Example 2]
Artificial leather was obtained in the same manner as in Example 1, except that the content of carbon black contained in the polymer elastomer was 1.5% by mass. The obtained artificial leather had excellent abrasion fastness and light fastness, and also had abrasion resistance. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Examples 3 and 4]
Artificial leather was obtained in the same manner as in Example 1, except that the ratio of ultrafine fibers A to ultrafine fibers B in the fiber entanglement was 20:80 and 80:20 by mass. The obtained artificial leather had excellent abrasion fastness and light fastness, and also had abrasion resistance. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Example 5]
Artificial leather was obtained in the same manner as in Example 1 except that the content of carbon black contained in the polymer elastomer was 3.0% by mass. The obtained artificial leather had excellent light fastness and abrasion resistance, although its abrasion fastness was slightly inferior. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Example 6]
Artificial leather was obtained in the same manner as in Example 1 except that the content of carbon black contained in ultrafine fiber A was 3.0% by mass. The obtained artificial leather had excellent abrasion fastness and light fastness, although its abrasion resistance was slightly inferior. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Example 7]
Artificial leather was obtained in the same manner as in Example 1, except that the black pigment contained in ultrafine fiber A was titanium black. The obtained artificial leather had excellent abrasion fastness and light fastness, although its abrasion resistance was slightly inferior. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Example 8]
Artificial leather was obtained in the same manner as in Example 1, except that the black pigment contained in the polymeric elastomer was titanium black. The obtained artificial leather had excellent light fastness and abrasion resistance, although its abrasion fastness was slightly inferior. Furthermore, the surface of the artificial leather had a uniform hue and a good texture. The results are shown in Table 1.

[Comparative example 1]
Artificial leather was obtained in the same manner as in Example 1, except that the ratio of ultrafine fibers A to ultrafine fibers B in the fiber entanglement was 0:100 in terms of mass ratio, that is, the fiber entanglement was composed only of ultrafine fibers B. . The obtained artificial leather was inferior in fastness to rubbing and fastness to light compared to Example 1. The results are shown in Table 2.

[Comparative example 2]
Artificial leather was obtained in the same manner as in Example 1, except that the variation in the occupancy of ultrafine fibers B on the surface of the fiber entangled body was 15.0%. The obtained artificial leather had large surface hue variations and poor surface hue uniformity compared to Example 1. The results are shown in Table 2.

[Comparative example 3]
The sea-island composite fiber with a single fiber fineness of 3.8 dtex described in Example 1 was cut into a length of 5 mm and then immersed in trichlorethylene to produce ultrafine fibers A and B with a single fiber fineness of 4.4 μm. Fibers A and ultrafine fibers B were dispersed in water so that the mass ratio was 50:50, and a paper sheet having a basis weight of 100 g/m ² was produced by a paper-making method and used as a surface fiber layer. A paper sheet having a basis weight of 50 g/m ² was produced in the same manner and used as the back fiber layer. A woven fabric made of polyester resin was inserted as a scrim between the front fiber layer and the back fiber layer to form a sheet with a three-layer structure. Next, a fiber entangled body was obtained by spraying a high-speed water stream. The surface layer of this fiber entangled body was buffed with sandpaper to obtain a raised fiber entangled body. Next, an elastomer containing a black pigment was applied to the raised fiber entangled body to obtain artificial leather. Note that the mass ratio of the polymer elastic body to the artificial leather was 10% by mass. The obtained artificial leather had a feel inferior to that of Example 1. The results are shown in Table 2.

As shown in Examples 1 to 8 in Table 1, by blending ultrafine fiber A and ultrafine fiber B, the resulting artificial leather has a uniform surface hue in the range from light to dark. It has excellent abrasion fastness and light fastness, and also has abrasion resistance.

On the other hand, as shown in Comparative Example 1, when the fiber entanglement contained in artificial leather is composed only of ultrafine fibers B, it is easy to become contaminated due to the large amount of dye used, and the dye deteriorates due to light irradiation. Since the hue of the fibers changes significantly, the resulting artificial leather has poor fastness to rubbing and fastness to light.

In addition, as shown in Comparative Example 2, when there is a large variation in the occupancy rate of the ultrafine fibers B on the surface of the fiber entangled body, the variation in the hue of the surface becomes large, so that the resulting artificial leather has poor uniformity of the surface hue. becomes.

In addition, as shown in Comparative Example 3, when the proportion of the polymer elastic body to the mass of the artificial leather is small, the bond between the fibers by the polymer elastic body is weak and the flexibility is low, so the resulting artificial leather has a high resistance to It becomes inferior in abrasion resistance and texture.

Claims (6)

Ultrafine fibers A made of polyester resin and having an average single fiber diameter of 1.0 μm or more and 6.0 μm or less and polyester resin and having an average single fiber diameter of 1.0 μm or more and 6.0 μm or less An artificial leather comprising a fiber entangled body consisting of ultrafine fibers B and a polymeric elastic body containing a black pigment, the artificial leather satisfying all of the following requirements 1 to 5 .
Requirement 1: The ultrafine fiber A contains a black pigment, and the content of the black pigment is 0.01% by mass or more and 1.0% by mass or less based on the mass of the ultrafine fiber A.
Requirement 2: The mass ratio of the ultrafine fibers A in the fiber entangled body is 10% by mass or more and 90% by mass or less.Requirement 3: The variation in the occupation rate of the ultrafine fibers B on the surface of the fiber entangled body is 10% or less. is
Requirement 4: The L ^* value of the surface of the fiber entangled body is 25 or more and 80 or less.
Requirement 5 : The mass ratio of the polymer elastic body in the artificial leather is 15% by mass or more and 50% by mass or less. The artificial leather according to claim 1, wherein the content of the black pigment contained in the polymeric elastomer is 0.01% by mass or more and 2.0% by mass or less. The artificial leather according to claim 1 or 2 , wherein the black pigment meeting requirement 1 is carbon black. The artificial leather according to any one of claims 1 to 3 , wherein the black pigment contained in the elastomer polymer is carbon black. The method for producing artificial leather according to any one of claims 1 to 4, comprising the following steps (1) to ( 4 ).
Step (1): Ultrafine fiber developed fiber A ₀ with a fiber length of 25 mm or more and 90 mm or less, and microfine fiber developed fiber B ₀ with a fiber length of 25 mm or more and 90 mm or less, are mixed so that the mass ratio of the ultrafine fiber developed fiber A ₀ is 10 Step (2) of manufacturing a fiber entangled body by opening the blended raw cotton so as to have a content of not less than 90% by mass and then needle punching: the ultrafine fiber-expressing fiber A ₀ and the Ultrafine fiber-expressing fiber B ₀ is made of ultrafine fiber A with an average single fiber diameter of 1.0 μm or more and 6.0 μm or less, and a polyester resin, and the average single fiber diameter is 1.0 μm or more. Process for developing ultrafine fibers B having a diameter of 6.0 μm or less Step (3): Adding a polymeric elastic body containing a black pigment to the mass of the artificial leather in an amount of 15% by mass or more and 50% by mass or less, Obtaining a sheet-like product Step (4): Raising and dyeing the sheet-like product The method for producing artificial leather according to claim 5 , wherein the ultrafine fiber developed fiber A ₀ and the ultrafine fiber developed fiber B ₀ have crimps.