Artificial leather, method for producing same, interior material for vehicle, and seat

Abstract

An artificial leather which contains, as a main constituent element, fibers that are formed from a polyester resin and have an average single fiber diameter of 2.0-7.0 [mu] m, the fibers being long fibers and dispersed as single fibers, the heat of fusion [Delta] Hm being 10-100 J / g, and the half-value width of the melting peak being 9 DEG C or more. Provided is an artificial leather having both a beautiful and high-grade appearance and mechanical properties at a high level, and also provided is a method for producing an artificial leather capable of further reducing the burden on the environment and improving productivity.

Description

Technical Field

[0001] The present invention relates to artificial leather having beautiful appearance and physical properties, a method for producing the same, and a vehicle interior material and a seat made of the artificial leather. Background Art

[0002] Artificial leather with a pile-covered surface obtained from ultrafine fibers has a beautiful appearance and is therefore used in a wide range of fields such as clothing, furniture, and automobile interior materials. Such artificial leather is made into a uniform sheet by a method of cross-laying a web obtained from short fibers of an ultrafine fiber production type, thereby achieving a high level of appearance and physical properties.

[0003] However, in recent years, there has been a growing demand for higher levels of appearance and physical properties, and there has been a demand for simplification of processes due to an increase in environmental awareness.

[0004] For example, Patent Document 1 proposes an ultrafine polyester stretched fiber for papermaking, which is a polyester stretched fiber with a fineness of less than 0.5 dtex and a specific fiber length, characterized in that a certain amount of polyether-polyester copolymer is attached to the fiber surface based on the fiber weight, and the moisture retention rate is above a certain value.

[0005] In addition, Patent Document 2 proposes a method for manufacturing mechanical materials for artificial leather, which includes the following steps: a step of forming a fiber web with ultrafine fiber generating fibers that can produce ultrafine fibers with an average single fineness of less than 0.5 dtex; a step of configuring a brush belt in such a manner that the front end of the brush contacts at least one side of the fiber web, holding the ultrafine fiber generating fibers protruding from the fiber web in the brush, and needle-punching the fiber web to obtain a bonded non-woven fabric; a step of making the bonded non-woven fabric contain a polymer elastomer; and a step of converting the ultrafine fiber generating fibers into a fiber bundle of ultrafine fibers with an average single fineness of less than 0.5 dtex.

[0006] In addition, Patent Document 3 proposes a method for manufacturing suede-like artificial leather, which is characterized in that a high-speed fluid stream is sprayed on a non-woven fiber web containing ultrafine fibers of 0.5 denier or less as essential components, or on a composite sheet having an organic woven fabric laminated on the back or inner layer of the non-woven fiber web, so that the constituent fibers are entangled, and an elastic polymer is filled into the gaps in the non-woven fabric or a non-woven fabric-like object having at least one non-woven fabric layer surface to manufacture artificial leather, and then the surface of the non-woven fabric layer of the non-woven fabric or the non-woven fabric-like object is subjected to a raising treatment, and then a paste that prevents the filling of the elastic polymer is applied to the raised surface, and then the elastic polymer is filled and the paste is removed.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-339257

[0010] Patent Document 2: International Publication No. 2006 / 134966

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 55-084479 Summary of the invention

[0012] Problems to be solved by the invention

[0013] In the case where the technology disclosed in Patent Document 1 is used as the base material of artificial leather, or in the case where artificial leather is obtained by the process of papermaking ultrafine fibers disclosed in Patent Document 3, it can be considered that the process is simplified compared with the previous artificial leather in that there is no need for the process of producing ultrafine fibers. On the other hand, in order to evenly disperse the fibers in water, it is necessary to shorten the fiber length, and it is difficult to obtain an artificial leather with a beautiful and high-grade appearance and high physical properties. In addition, in order to prevent the fibers from tangling in water, the fibers need to be rigid. Therefore, it is also difficult to soften the touch of the pile.

[0014] On the other hand, according to the manufacturing process based on the spunbond method disclosed in Patent Document 2 and the manufacturing process based on the meltblowing method disclosed in Patent Document 3, the process of forming a web of crimped short fibers, which is usually used in the manufacture of artificial leather, can be omitted. It can also be considered that the simplification of the process will be easier than that of conventional artificial leather in this regard. In addition, unlike the technology disclosed in Patent Document 1 and the process of making ultrafine fibers disclosed in Patent Document 3, it is not necessary to disperse them in water, so it can be considered that it is easy to suppress the rigidity of the fibers to a low level, and it is relatively easy to obtain artificial leather with a soft tactile pile. However, in the technology disclosed in Patent Document 2, since ultrafine fiber generating fibers are used, the ultrafine fibers generated by the same ultrafine fiber generating fibers are easily aggregated to form fiber bundles, and it is difficult to obtain a sheet with a uniform appearance in which the fibers are dispersed one by one. In addition, with the meltblowing method disclosed in Patent Document 3, the rigidity of the fibers becomes too soft, resulting in a touch without toughness and difficulty in obtaining sufficient physical properties.

[0015] Therefore, an object of the present invention is to provide an artificial leather that has both an elegant and high-quality appearance and mechanical properties at a high level, and to provide a method for producing artificial leather that can further reduce environmental burden and improve productivity.

[0016] Means for solving problems

[0017] In order to solve the above problems, the present invention has the following configuration.

[0018] [1] Artificial leather comprising as main components fibers formed from a polyester resin and having an average single fiber diameter of 2.0 μm to 7.0 μm, wherein the fibers are long fibers and dispersed in the form of single fibers, the heat of fusion ΔHm of the artificial leather being 10 J / g to 100 J / g, and the half-value width of the melting peak being 9°C or more.

[0019] [2] The artificial leather according to [1], which has pile on at least one surface.

[0020] [3] The artificial leather according to [1] or [2], further comprising as a constituent a layer formed of reinforcing fibers having an average single fiber diameter of 5.0 μm to 25.0 μm.

[0021] [4] The artificial leather according to any one of [1] to [3], further comprising polyurethane as a constituent, wherein the content of the polyurethane is 5% by mass or more and 50% by mass or less.

[0022] [5] The artificial leather according to any one of [1] to [3], wherein the cross-sectional irregularity of the fiber is 1.00 to 1.15.

[0023] [6] A method for producing artificial leather as described in any one of [1] to [5] above, comprising the following steps: after a molten polyester resin is ejected from a spray hole of a spinneret at a single-hole ejection rate of 0.05 g / min to 0.30 g / min, a gas at a temperature of -15°C to 50°C is blown onto the polyester resin in at least a portion of an area within 200 mm from the ejection hole to form filaments, and at least in an inlet, the filaments are pulled by a gas at a temperature of -15°C to 50°C at a spinning speed Vs (m / min) of 3,000 m / min to 7,000 m / min to obtain a web formed by fibers having an average single fiber diameter of 2.0 μm to 7.0 μm.

[0024] [7] The method for producing artificial leather according to [6], wherein the ratio Vq / Vs of the gas flow rate Vq (m / min) when the gas is blown to the spinning speed Vs (m / min) is set to 3×10 -3 Above 30×10 -3 the following.

[0025] [8] The method for producing artificial leather according to [6] or [7] above, wherein the distance between the ejection hole and the introduction port is set to be 100 mm to 3,000 mm.

[0026] [9] The method for producing artificial leather according to any one of [6] to [8] above, wherein the hole diameter of the ejection hole is 0.05 mm or more and 0.30 mm or less.

[0027]

[10] A vehicle interior material comprising the artificial leather described in any one of [1] to [5] above.

[0028]

[11] A seat made using the artificial leather described in any one of [1] to [5] above.

[0029] Effects of the Invention

[0030] According to the artificial leather of the present invention, both a beautiful and high-grade appearance and mechanical properties can be achieved at a high level. Moreover, according to the method for producing artificial leather of the present invention, the environmental burden can be further reduced and productivity can be improved. In addition, due to the excellent properties of the artificial leather, it can be particularly suitably used in vehicle interior materials or seats. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a conceptual cross-sectional view for illustrating and explaining one embodiment of the production apparatus for artificial leather according to the present invention. DETAILED DESCRIPTION

[0032] The artificial leather of the present invention is an artificial leather comprising fibers formed of a polyester resin and having an average single fiber diameter of 2.0 μm or more and 7.0 μm or less as main components, the fibers are long fibers and dispersed in the form of single fibers, and the heat of fusion (ΔHm) of the artificial leather is 10 J / g or more and 100 J / g or less. The components are described in detail below, and the present invention is not limited to the scope of the following description as long as it does not exceed the gist of the present invention, and various changes can be made within the scope of the gist of the present invention.

[0033] Here, in the present invention, “containing fibers as a main component” means that the fibers are contained in a portion excluding a layer formed of reinforcing fibers and polyurethane described later from the artificial leather so that the mass ratio of the fibers is 50 mass % or more.

[0034] In addition, in the present invention, the so-called "long fiber" refers to a substantially continuous fiber with a fiber length of 100 mm or more, which is not a short fiber intentionally cut after spinning. More specifically, for example, it refers to a fiber that is not intentionally cut into a short fiber with a fiber length of about 3 to 80 mm. However, in the process of manufacturing artificial leather, after the polyester resin is spun into a sheet, the cut portion of the fiber, such as the fiber at the end formed by cutting the sheet, or the fiber on the surface formed by forming a pile on the surface of the sheet, is still considered as a long fiber even if it is cut into a certain length.

[0035] In the present invention, the fiber "dispersed in the form of single fibers" means that there is no fiber bundle on the surface where multiple fibers are gathered to form thick fibers. This state can be confirmed by observation with a stereo microscope or an electron microscope. Specifically, a randomly selected area of ​​1 cm×1 cm is observed, and fiber bundles in which 10 or more fibers are gathered and continuous within a length range of 1 mm or more are counted. In 10 areas, the number of fiber bundles is counted in the same way. If the average value is 3 or less, the fiber is judged to be "dispersed in the form of single fibers."

[0036] [fiber]

[0037] The artificial leather of the present invention comprises fibers formed of a polyester resin as a main component, and thus can be produced to have both a beautiful and high-quality appearance and mechanical properties at a high level and excellent durability.

[0038] Examples of the polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polylactic acid, and polyester elastomers. Among these, polyethylene terephthalate and polybutylene terephthalate are more preferred from the perspective of the feel and practical performance of the processed product, and polyethylene terephthalate is particularly preferred.

[0039] It should be noted that, in the present invention, the so-called polyester resin refers to each polyester resin such as the above-mentioned polyethylene terephthalate, their mixtures, copolymers, and those obtained by adding additives to these resins. Such additives are substances added or contained according to various purposes within the range that does not hinder the purpose of the present invention, and specifically, inorganic particles such as titanium oxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, antibacterial agents, etc. can be cited.

[0040] Moreover, in the artificial leather of the present invention, the average single fiber diameter of the above-mentioned fibers is 2.0 μm or more and 7.0 μm or less. If it deviates from this range, a soft and smooth touch cannot be obtained, the shape of the nonwoven fabric is unstable, and the handling property is poor. The lower limit of the range of the average single fiber diameter is preferably 2.5 μm or more, and more preferably 3.0 μm or more, whereby the morphological stability of the artificial leather becomes higher. On the other hand, the upper limit of the range of the average single fiber diameter is preferably 6.0 μm or less, and more preferably 5.0 μm or less, whereby the artificial leather becomes softer.

[0041] In addition, in the artificial leather of the present invention, the average single fiber diameter (μm) means a value calculated as follows.

[0042] (1) Cut out five test pieces of 2 cm x 2 cm.

[0043] (2) A cross section of the test piece is photographed using a scanning electron microscope (“VHX-D510” manufactured by KEYENCE CORPORATION or a differential scanning calorimeter having equivalent performance).

[0044] (3) Randomly select 20 circular or nearly circular elliptical fibers.

[0045] (4) Measure the diameters of 20 single fibers.

[0046] (5) (2) to (4) are performed on all test pieces, and the arithmetic mean value (μm) of the single fiber diameters obtained is calculated and rounded off to the second decimal place.

[0047] In the artificial leather of the present invention, the fibers are long fibers because long fibers not only easily provide high strength but also prevent the fibers from falling off from the artificial leather, thereby providing good wear resistance.

[0048] In the artificial leather of the present invention, the fibers are dispersed in the form of single fibers. The ultrafine fibers constituting the artificial leather are dispersed in the form of single fibers, so that the entire artificial leather has a uniform structure and a high-quality appearance can be obtained.

[0049] Generally, in artificial leather using ultrafine fiber-generating fibers, a process such as entanglement is performed to form a structure in the form of ultrafine fiber-generating fibers. In the ultrafine fiber-generating process, a plurality of ultrafine fibers in the ultrafine fiber-generating fibers form a fiber bundle, and thus are not dispersed in the form of single fibers. If the structure is formed by such a fiber bundle, there is a tendency to form an entangled portion and a surface with the size of the fiber bundle, so it is difficult to easily obtain a uniform structure as expected in the present invention. Furthermore, depending on the situation, a clear lighting effect may not be obtained, and the quality may deteriorate.

[0050] It should be noted that even if a part of the artificial leather contains a structure in which the fiber bundles are entangled due to manufacturing constraints, as long as the ultrafine fibers that substantially constitute the artificial leather are dispersed in the form of short fibers, the content ratio of the structure in which the fiber bundles are entangled is within the range that does not impair the effect of the present invention. However, sometimes the effect of the present invention cannot be fully obtained, so it is necessary to pay attention.

[0051] Moreover, in the artificial leather of the present invention, the cross-sectional profile of the aforementioned fiber is preferably 1.00 or more and 1.15 or less. If the profile is 1.00, which is the lower limit, it means that the cross section of the fiber is a perfect circle, and as the profile increases, the cross section of the fiber deforms from the perfect circle to different directions. The upper limit of the range of the profile is more preferably 1.10 or less, and further preferably 1.05 or less, whereby the anisotropy of the fiber is further suppressed when it is bent, so that when a pile is formed on the surface of the artificial leather, the pile formed on the surface of the artificial leather is easy to be neat, and an artificial leather with a high-grade feel can be made.

[0052] In addition, in the artificial leather of the present invention, the irregularity degree means a value calculated as follows.

[0053] (1) Cut out five test pieces of 2 cm x 2 cm. When the test pieces are cut out from a product using artificial leather, randomly collect them from the product except for the seams and embossed portions.

[0054] (2) A cross section of the test piece is photographed using a scanning electron microscope (“VHX-D510” manufactured by KEYENCE CORPORATION or a differential scanning calorimeter having equivalent performance).

[0055] (3) 10 fibers are randomly selected and, in order to observe the accurate shape of each fiber cross section, images are taken in a direction in which the fiber side faces of the corresponding fibers are not captured at all or are minimized.

[0056] (4) For a selected fiber cross section, the fiber irregularity (unitless) is calculated by dividing the diameter (μm) of the smallest circumscribed circle of the cross section by the diameter (μm) of the largest inscribed circle of the cross section.

[0057] (5) (2) to (4) are performed on all test pieces, and the arithmetic mean (unitless) of the obtained irregularity is rounded off to the third decimal place.

[0058] [Artificial leather]

[0059] The artificial leather of the present invention comprises the aforementioned fiber as a main component. Moreover, the melting heat ΔHm of the artificial leather of the present invention is 10 J / g or more and 100 J / g or less. In the present invention, the melting heat ΔHm refers to the melting heat ΔHm derived from polyester, and the larger the melting heat ΔHm, the higher the crystallinity of the resin constituting the fiber. It should be noted that the melting heat of the present invention is measured and calculated based on the mass of the fiber formed by the polyester resin in the artificial leather as described later. Moreover, even if polyurethane is included, it is measured in the state of the artificial leather, and the content ratio of the polyurethane is deducted, and the mass of the fiber formed by the polyester resin in the artificial leather is measured and calculated based on the mass of the fiber formed by the polyester resin in the artificial leather. When the melting heat ΔHm of the artificial leather deviates from the range of 10 J / g or more and 100 J / g or less, it is impossible to expect the mechanical properties of the fiber to be improved, and broken threads and fluff will occur, and it is impossible to make an artificial leather with a soft and gentle touch.

[0060] The lower limit of the range of the heat of fusion ΔHm is preferably 20 J / g or more, more preferably 30 J / g or more, whereby the crystallinity of the resin constituting the fiber is further developed, and thus the mechanical properties of the fiber are further improved, and the generation of broken wires and fuzz can be suppressed. As a result, artificial leather with better mechanical properties can be produced. On the other hand, the upper limit of the range of the heat of fusion ΔHm is preferably 60 J / g or less, more preferably 45 J / g or less, whereby excessive crystallization can be suppressed, and thus artificial leather with a softer and gentler touch can be produced.

[0061] In addition, in the artificial leather of the present invention, the heat of fusion ΔHm means a value measured and calculated as follows.

[0062] (1) Cut out five test pieces of 2 cm x 2 cm. When cutting test pieces from artificial leather products, randomly pick them from the product except for seams and embossed parts, and use them under standard conditions adjusted to 20±2°C and 65±4% relative humidity.

[0063] (2) Using a differential scanning calorimeter (differential scanning calorimeter "Q20" manufactured by TA Instruments Japan Co., Ltd. or a differential scanning calorimeter having equivalent performance), the temperature was raised from 20°C to 300°C at a rate of 10°C / min, and the heat of fusion (J) was measured from the heat balance of the melting peak located between 200°C and 300°C. At this time, if there is an exothermic peak between 100°C and 200°C, the value obtained by subtracting the exothermic heat (J) from the above-mentioned heat of fusion (J) was used as the heat of fusion (J).

[0064] (3) The heat of fusion (J) is divided by the mass (g) of the fiber formed by the polyester resin to obtain the heat of fusion ΔHm. At this time, when the artificial leather contains components other than the polyester resin such as polyurethane, the artificial leather is immersed in a solvent that dissolves the ultrafine fibers (fibers with an average single fiber diameter of 2.0 μm or more and 7.0 μm or less in the artificial leather) and the reinforcing fibers described below, or in a solvent that dissolves the polyurethane, and the heat of fusion ΔHm is calculated based on the change in mass before and after dissolution. For example, in the case of artificial leather containing organic solvent-based polyurethane, the artificial leather is often immersed in N,N'-dimethylformamide, and after the polyurethane is dissolved and removed, the mass of the remaining ultrafine fibers and reinforcing fibers is measured, thereby calculating the mass of the fiber formed by the polyester resin.

[0065] (4) Perform (2) to (3) for all test pieces, calculate the arithmetic mean (J / g) of the heat of fusion ΔHm obtained, and round off to the first decimal place.

[0066] The heat of fusion ΔHm can be adjusted to the above range by, for example, the spinning speed, spinning temperature, cooling conditions, molecular weight of the polyester resin, type of copolymer components of the polyester resin, copolymerization ratio, type and amount of additives such as crystal nucleating agents, etc.

[0067] The half-value width of the melting peak of the artificial leather of the present invention is 9° C. or more. In the present invention, the so-called melting peak refers to the melting peak derived from polyester, and the larger the half-value width, the easier it is to achieve both physical properties and soft touch. If the half-value width of the melting peak of the artificial leather is less than 9° C., it is impossible to obtain an artificial leather with soft and soft touch.

[0068] The lower limit of the half-value width of the melting peak is preferably 11°C or more, more preferably 13°C or more, so that artificial leather with a softer and gentle touch can be obtained. The upper limit is not particularly limited, but is preferably 20°C or less, more preferably 18°C ​​or less, and further preferably 16°C or less from the perspective of easily improving the mechanical properties of the fiber.

[0069] It should be noted that in the present invention, the half-value width of the melting peak is a value obtained simultaneously with the measurement of the heat of fusion. Specifically, it is a value obtained by reading the half-value width (°C) at the melting peak located between 200°C and 300°C in (2) of the measurement of the heat of fusion.

[0070] The half width of the melting peak can be adjusted to the above range by, for example, adjusting the spinning speed, spinning temperature, cooling conditions, molecular weight of the polyester resin, copolymer components of the polyester resin, and adding additives such as a crystal nucleating agent.

[0071] The artificial leather of the present invention has the characteristics of achieving both a beautiful and high-grade appearance and mechanical properties at a high level, further reducing the environmental burden, and improving productivity. It can adopt various appearances such as a silver surface effect surface without pile, a suede-like surface with pile, and a nappa-like surface. Among them, it is a preferred embodiment to have pile on at least one surface. In the present invention, the so-called "pile-having" surface refers to a surface having a nap layer of ultrafine fibers, and the ultrafine fibers have a length and direction softness to the extent that a so-called finger mark can be revealed by running a finger across the surface.

[0072] The artificial leather of the present invention is composed of long fibers and therefore has high physical properties. To obtain even higher physical properties, the artificial leather is preferably made into an artificial leather comprising a layer composed of reinforcing fibers having an average single fiber diameter of 5.0 μm to 25.0 μm as a constituent element.

[0073] The upper limit of the average single fiber diameter of the reinforcing fiber is preferably 25.0 μm or less, more preferably 15.0 μm or less, and further preferably 13.0 μm or less, thereby obtaining an artificial leather having excellent softness. On the other hand, the lower limit of the average single fiber diameter is preferably 5.0 μm or more, more preferably 7.0 μm or more, and further preferably 10.0 μm or more, thereby improving the morphological stability of the product as an artificial leather.

[0074] It should be noted that in the present invention, the average single fiber diameter of the reinforcing fibers is a value calculated as follows: a scanning electron microscope (SEM) photograph of a cross section of artificial leather is taken, 10 reinforcing fibers constituting a layer formed by reinforcing fibers are randomly selected, the single fiber diameters of the fibers are measured, and the arithmetic mean value (μm) of the 10 fibers is calculated, and the arithmetic mean value (μm) after rounding off to the second decimal place is calculated. In the case of using fibers with a special cross section, the cross-sectional area (μm) of the fibers is first measured in the same manner as in the case of measuring and calculating the average single fiber diameter of the fibers constituting artificial leather. 2 ), calculate the diameter when the cross section is regarded as a circle, that is, the equivalent circle diameter, thereby obtaining the diameter (μm) of the fiber. In addition, when the reinforcing fiber is a multifilament as described later, the diameter of the single fiber constituting the multifilament is set as the average single fiber diameter of the reinforcing fiber.

[0075] The layer formed of the reinforcing fibers may be a woven fabric layer. The basic weave of the woven fabric layer may be twill or satin, but a plain weave that is less likely to cause weaving defects may be preferably used.

[0076] As the type of fiber constituting the woven fabric layer, filament yarn, spun yarn, mixed composite yarn of filament yarn and spun yarn, etc. are preferably used. From the viewpoint of durability, especially mechanical strength, multifilament obtained from polyester resin or polyamide resin is more preferably used.

[0077] Furthermore, in the case of a multifilament constituting the aforementioned woven fabric, the twist number of the multifilament is preferably set to 1,000 T / m to 4,000 T / m. By setting the upper limit of the range of the twist number to 4,000 T / m or less, more preferably 3,500 T / m or less, and further preferably 3,000 T / m or less, an artificial leather having excellent softness can be obtained. On the other hand, by setting the lower limit of the range of the twist number to 1,000 T / m or more, more preferably 1,500 T / m or more, and further preferably 2,000 T / m or more, when the nonwoven fabric and the woven fabric are entangled and integrated by needle punching, etc., it is possible to prevent damage to the fibers constituting the woven fabric, and the mechanical strength of the artificial leather is excellent, which is preferred.

[0078] In order to adjust the feel and physical properties of the artificial leather of the present invention, it is further preferred to prepare an artificial leather containing polyurethane as a constituent element. As the polyurethane, a polyurethane obtained by reacting a polymer diol, an organic diisocyanate and a chain extender is preferably used.

[0079] As the polymer diol used in the polyurethane of the present invention, at least one polymer diol selected from polyester diol, polyether diol, polycarbonate diol, or polyester polyether diol having an average molecular weight of 500 to 3,000 can be used. Preferably, the polyurethane contains a polyether diol or polycarbonate diol having excellent hydrolysis resistance and which is not easily damaged in the case of repeated washing as a binder.

[0080] In addition, the polyurethane according to the present invention may contain various additives according to the purpose, for example, pigments such as carbon black, flame retardants such as phosphorus-based, halogen-based and inorganic-based flame retardants, antioxidants such as phenol-based, sulfur-based and phosphorus-based antioxidants, ultraviolet absorbers such as benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based and oxalic acid anilide-based ultraviolet absorbers, hindered amine-based, benzoate-based light stabilizers, hydrolysis stabilizers such as polycarbodiimide, plasticizers, antistatic agents, surfactants, coagulation regulators and dyes.

[0081] Usually, the proportion of polyurethane in artificial leather can be suitably adjusted considering the type of polyurethane used, the method for manufacturing polyurethane and the feel and physical property of desired artificial leather, etc. In the artificial leather of the present invention, the proportion of polyurethane is preferably set to 5% by mass or more and 50% by mass or less. By making the lower limit of the scope of the proportion of polyurethane to be 5% by mass or more, more preferably 10% by mass or more, the wear resistance of artificial leather can be improved. On the other hand, by making the upper limit of the scope of the proportion of polyurethane to be 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, the softness of artificial leather can be made higher.

[0082] In addition, in this invention, the content rate of polyurethane in artificial leather means the value measured and calculated by the following method.

[0083] (1) Cut out five test pieces of 2 cm x 2 cm and measure the mass of the test pieces. When test pieces are cut out from a product made of artificial leather, randomly collect them from the product except for the seams and embossed parts and use them under standard conditions adjusted to 20±2°C and 65±4% relative humidity.

[0084] (2) The artificial leather is immersed in a solvent that dissolves the ultrafine fibers and reinforcing fibers, or in a solvent that dissolves the polyurethane, and the polyurethane content (g) is calculated based on the mass change before and after dissolution. For example, in the case of artificial leather containing organic solvent-based polyurethane, the artificial leather is often immersed in N,N'-dimethylformamide, and after the polyurethane is dissolved and removed, the mass of the remaining ultrafine fibers and reinforcing fibers is measured, thereby calculating the polyurethane content (g).

[0085] (3) The polyurethane content obtained in (2) was divided by the mass (g) of the test piece obtained in (1) to calculate the polyurethane content (mass %).

[0086] (4) (2) to (3) were performed on all test pieces, and the arithmetic mean (mass %) of the polyurethane content ratios (mass %) obtained was calculated and rounded off to the first decimal place.

[0087] [Manufacturing method of artificial leather]

[0088] The method for producing artificial leather of the present invention comprises the steps of: after a molten polyester resin is ejected from an ejection hole of a spinneret under the condition of a single-hole ejection rate of 0.05 g / min to 0.30 g / min, a gas of -15°C to 50°C is blown to the polyester resin so as to include at least a part of a region within 200 mm from the ejection hole to form a filament; and the filament is drawn by the gas of -15°C to 50°C at least in an inlet at a spinning speed of 3,000 m / min to 7,000 m / min to obtain a web formed of fibers having an average single fiber diameter of 2.0 μm to 7.0 μm. The "inlet" in the present invention refers to a portion where the wind speed of the drawn gas is the highest between the ejection hole and the web, and is generally a portion where the cross-sectional area of ​​the passage through which the resin ejected from the ejection hole passes to become the filament is the smallest between the ejection hole and the web. The details of the production method will be described later. Of course, in this part, the present invention is not limited to the scope of the following description as long as it does not exceed the gist of the present invention, and various changes can be made without departing from the gist of the present invention.

[0089] First, in the method for producing artificial leather of the present invention, the molten polyester resin is ejected from the ejection hole of the spinneret under the condition of a single hole ejection amount of 0.05 g / min to 0.30 g / min. If the single hole ejection amount deviates from the range of 0.05 g / min to 0.30 g / min, stable spinnability cannot be obtained within the range of the spinning speed described later, or fibers with an average single fiber diameter of 7.0 μm or less for obtaining an artificial leather with a beautiful appearance cannot be easily obtained. It should be noted that in the present invention, the single hole ejection amount (g / min) refers to the ejection amount (g) of the polyester resin ejected from one ejection hole (single hole) of the spinneret per unit time (minute). The lower limit of the range of the single hole ejection amount is preferably set to 0.07 g / min or more, and more preferably set to 0.09 g / min or more, so that more stable spinnability can be obtained within the range of the spinning speed described later. On the other hand, the upper limit of the range of single-hole ejection volume is preferably set to less than 0.25 g / minute, and more preferably set to less than 0.20 g / minute, so that fibers with an average single fiber diameter of less than 7.0 μm can be more easily obtained within the range of spinning speeds described later for obtaining artificial leather with a beautiful appearance.

[0090] At this time, the aperture of the aforementioned ejection hole is preferably set to be 0.05 mm or more and 0.30 mm or less. As for the lower limit of the range of the aperture, it is more preferably set to be 0.07 mm or more, and further preferably set to be 0.09 mm or more, so as to effectively suppress the adhesion of stains and the like, thereby causing the spinnability to decrease over time. On the other hand, as for the upper limit of the range of the aperture, it is more preferably set to be 0.25 mm or less, and further preferably set to be 0.20 mm or less, so as to more easily obtain a stable spinning state. In the present invention, when the ejection hole is not a perfect circle, the diameter of a perfect circle with the same hole area (equivalent circle diameter) is referred to as the aperture.

[0091] Furthermore, in the method for producing artificial leather of the present invention, after the molten polyester resin is ejected from the ejection hole of the spinneret, a gas at a temperature of -15°C or higher and 50°C or lower is blown at at least a portion of the region within 200 mm from the ejection hole to form a filament. When obtaining fibers of a normal fineness, since the temperature of the ejection hole is affected and the spinning is easily unstable, blowing at a position close to the ejection hole is generally avoided. However, the inventors of the present application have found that when spinning to obtain ultrafine fibers, the spinning is stabilized by blowing the gas at a position close to the ejection hole.

[0092] It should be noted that the area where the aforementioned gas is blown includes at least a portion of the area within 200 mm from the aforementioned ejection hole. If at least a portion of the area within 200 mm from the aforementioned ejection hole is not included, it is difficult to obtain fibers with an average single fiber diameter of less than 7.0 μm, and artificial leather with a beautiful appearance cannot be obtained. It is preferred to include at least a portion of the area within 150 mm from the aforementioned ejection hole, and it is more preferred to include at least a portion of the area within 100 mm from the aforementioned ejection hole. By doing so, it is easy to obtain fibers with an average single fiber diameter of less than 7.0 μm, which is usually difficult to obtain, and it is easier to obtain artificial leather with a beautiful appearance.

[0093] If the temperature of the gas to be blown deviates from the range of -15°C to 50°C, the temperature near the ejection hole will be excessively lowered, or the ejected polyester resin will not be sufficiently cooled. The lower limit of the temperature range of the gas is preferably set to -10°C or higher, more preferably -5°C or higher, so that the temperature near the ejection hole can be effectively prevented from being excessively lowered. On the other hand, the upper limit of the temperature range of the gas is preferably set to 40°C or lower, more preferably 30°C or lower, so that the ejected polyester resin can be more sufficiently cooled.

[0094] As a gas supply means for blowing the gas, there is a method of supplying the gas with a blower from one direction or a plurality of directions of the polyester resin through a slit nozzle or a rectifying unit.

[0095] Moreover, in the method for manufacturing artificial leather of the present invention, the distance between the ejection hole and the introduction port is preferably set to be greater than 100 mm and less than 3,000 mm. The lower limit of the range of the distance between the ejection hole and the introduction port is preferably set to be greater than 100 mm, more preferably set to be greater than 200 mm, and further preferably set to be greater than 300 mm, so that the fiberization of the molten polyester resin can be fully promoted and stable spinning can be performed more easily. On the other hand, the upper limit of the range of the distance between the ejection hole and the introduction port is preferably set to be less than 3,000 mm, more preferably set to be less than 2,000 mm, and further preferably set to be less than 1,000 mm, so that the filaments formed by the polyester resin ejected from the plurality of ejection holes can be more stably introduced into the introduction port.

[0096] Furthermore, in the method for producing artificial leather of the present invention, the spinning speed Vs (m / min) is set to 3,000 m / min to 7,000 m / min for the filaments at least in the introduction port. If the spinning speed Vs (m / min) deviates from the range of 3,000 m / min to 7,000 m / min, the molecular orientation becomes insufficient, and the tactile feel is not appropriately tough, and an artificial leather having excellent mechanical properties and morphological stability cannot be obtained, or the filaments blown with the gas cannot be stably pulled. The lower limit of the range of the spinning speed Vs (m / min) is preferably set to 3,500 m / min or more, and more preferably set to 4,000 m / min or more, so that the molecular orientation becomes more sufficient, the tactile feel is appropriately tough, and an artificial leather having excellent mechanical properties and morphological stability can be obtained more easily. On the other hand, the upper limit of the spinning speed Vs (m / min) is preferably 6,500 m / min or less, more preferably 6,000 m / min or less, so that the filaments blown with the gas can be pulled more stably.

[0097] In addition, in this invention, the spinning speed Vs (m / min) in the said introduction port is the value measured and calculated by the following method.

[0098] (1) After the aforementioned filaments are pulled and stretched, 10 small samples are randomly collected from the net captured on the collecting net, and surface photographs are taken at 500 to 1,000 times using a microscope. The widths of 10 fibers from each sample, for a total of 100 fibers, are measured, and the single fiber diameter (μm) is calculated from their arithmetic mean.

[0099] (2) The single fiber fineness (dtex) was calculated by rounding off the second decimal place based on the single fiber diameter and the density of the resin used at 20°C, with the mass per 10,000 m length being taken as the single fiber fineness.

[0100] (3) The spinning speed was calculated from the single fiber fineness (dtex) of (2) and the single hole discharge rate (g / min) set under each condition based on the following formula, and the first decimal place was rounded off.

[0101] Spinning speed (m / min) = (10,000 x single hole discharge amount (g / min)) / single fiber fineness (dtex).

[0102] In addition, the lower limit of the temperature range of the gas used when drawing the filaments is preferably set to -10°C or higher, more preferably -5°C or higher, so that the filaments can be cooled more uniformly. On the other hand, the upper limit of the temperature range of the gas is preferably set to 40°C or lower, more preferably 30°C or lower, so that the filaments can be cooled more sufficiently.

[0103] Furthermore, in the method for producing artificial leather of the present invention, the ratio Vq / Vs of the gas flow rate Vq (m / min) and the spinning speed Vs (m / min) when the gas is blown is preferably set to 3×10 -3 Above 30×10 -3 The lower limit of the range of Vq / Vs is preferably 3×10 -3 More preferably, 4×10 -3 More preferably, it is 5×10 -3 On the other hand, the upper limit of the range of Vq / Vs is preferably set to 30×10 -3 Below, more preferably 20×10 -3 Below, it is more preferably set to 10×10 -3 The following makes it possible to pull the thread more stably.

[0104] The above method can obtain a web composed of fibers having an average single fiber diameter of 2.0 μm to 7.0 μm. Furthermore, in the method for producing artificial leather of the present invention, for example, it is preferred to produce the artificial leather by performing at least one of the following steps.

[0105] (1) a step of providing the web with a layer further comprising reinforcing fibers to obtain a sheet substrate;

[0106] (2) a step of heat-treating the sheet substrate by shrinking the web or the sheet substrate by dry heat treatment, wet heat treatment, or both;

[0107] (3) a step of imparting polyurethane to the web, the sheet substrate, or the sheet substrate with polyurethane obtained by heat-treating the sheet substrate;

[0108] (4) a step of performing a raising treatment on at least one surface of any one of the net, the sheet substrate, the heat-treated sheet substrate, or the polyurethane-attached sheet substrate to form a pile sheet;

[0109] (5) A step of post-processing any one of the web, the sheet base, the heat-treated sheet base, the polyurethane-attached sheet base, or the pile sheet.

[0110] It should be noted that, when any of the above-mentioned steps (1) to (5) are not performed, the aforementioned net becomes artificial leather. In addition, when only (1) is performed, the aforementioned sheet substrate becomes artificial leather. In addition, when only (2) is performed, or when (1) and (2) are performed, the aforementioned heat-treated sheet substrate becomes artificial leather. In addition, when only (3) is performed, or when (1) and (3), (2) and (3), or (1) to (3) are performed, the aforementioned sheet substrate with polyurethane becomes artificial leather. The same applies to the pile sheet involved in the step (4). The material obtained after the step (5) will of course become artificial leather. The details of each step are further described below.

[0111] First, in the aforementioned process of obtaining a sheet substrate, it is also preferred to carry out a process of making the aforementioned web further have a layer formed by reinforcing fibers to obtain a sheet substrate. The layer formed by reinforcing fibers mentioned here refers to a layer formed by reinforcing fibers having an average single fiber diameter of 5.0 μm or more and 25.0 μm or less. By having this layer formed by reinforcing fibers, artificial leather with higher physical properties can be made. As a method for having a layer formed by the aforementioned reinforcing fibers, for example, a method of fusing the layer with the aforementioned web by heat, or bonding it with an adhesive, or using needle punching, water spunlace, etc. to entangle the reinforcing fibers with the fibers constituting the web can be adopted. In particular, since it is easy to entangle the 2.0 μm to 7.0 μm fibers constituting the aforementioned web with the reinforcing fibers, it is a more preferred method to use water spunlace to entangle them.

[0112] In the present invention, in order to make the obtained artificial leather more dense, it is also preferred to shrink the aforementioned net or the aforementioned sheet substrate by dry heat treatment, wet heat treatment, or both to obtain a heat-treated sheet substrate. As a specific example of dry heat treatment, hot air blowing can be cited. In addition, as a specific example of wet heat treatment, immersion in heated water can be cited. In addition, it is also preferred that the sheet subjected to these treatments is further subjected to heat pressing. In this way, the sheet subjected to dry heat treatment and wet heat treatment is made denser, and the form of the sheet can also be fixed or the surface can be smoothed.

[0113] Next, in the above-mentioned step of obtaining the sheet substrate with polyurethane, it is preferred to use a method of dissolving polyurethane or its precursor in a solvent such as N,N'-dimethylformamide, dimethyl sulfoxide (solvent method), and it is also preferred to use a method of using a water-dispersible polyurethane liquid (water dispersion method), wherein the water-dispersible polyurethane liquid is obtained by dispersing polyurethane or its precursor, that is, a mixture containing at least a polymer diol, an organic diisocyanate and a chain extender in water as an emulsion. In the case of the former solvent method, for example, a method of substantially solidifying and curing the precursor of polyurethane by dipping the net or the like in the above-mentioned polyurethane solution or the like and then drying it; or a method of solidifying the net or the like by dipping it in the above-mentioned polyurethane solution or the like and then dipping it in another solvent in which polyurethane is not soluble. On the other hand, in the case of the latter water dispersion method, for example, the net or the like can be solidified by a dry solidification method of dipping the net or the like in the above-mentioned water-dispersible polyurethane liquid or the like and then drying it. During drying, heating can be performed at a temperature that does not damage the performance of the net, the sheet substrate, or the sheet substrate with polyurethane.

[0114] Furthermore, in the aforementioned process of forming a pile sheet, the fluffing treatment performed on at least one surface of the aforementioned net or the like can be performed using sandpaper, a roller sander, or the like. Among them, by using sandpaper, a uniform and dense pile can be formed. In particular, in order to form a uniform pile on the surface of the aforementioned net or the like, it is preferred to reduce the grinding load in the fluffing treatment. As a specific method for reducing the grinding load, for example, a multi-stage polishing with a polishing level of 3 or more and a number of sandpaper used in each level being set to the range of 120 (P120) to 600 (P600) specified in JIS R 6010:2000 "Granularity of abrasive materials for abrasive cloth and paper" is a more preferred method.

[0115] Finally, in the post-processing step, the net or the like may contain functional chemical agents such as dyes, pigments, softeners, anti-pilling agents, antibacterial agents, deodorants, water repellents, light fasteners, and weather fasteners.

[0116] For example, the aforementioned net or the like may also be dyed. As a specific means for dyeing, a liquid flow dyeing machine is preferably used from the viewpoint that the aforementioned net or the like can be rubbed and softened while being dyed. The temperature of the dyeing liquid during dyeing is preferably 100° C. to 150° C. The dye is preferably an acid dye, a metal-containing dye, a reactive dye, etc. In addition, reduction cleaning may be performed after dyeing.

[0117] In addition, for the purpose of improving dyeing uniformity, it is also preferred to use a dyeing auxiliary when dyeing is performed. Furthermore, a finishing treatment of a softener such as an organosilicon compound, an antistatic agent, a water repellent, a flame retardant, and a light fastness agent may also be performed. The finishing treatment may be performed after dyeing or in the same bath as dyeing.

[0118] Alternatively, various hole-forming processes (punching processes), embossing processes, sewing processes, foil processes, resin printing processes, inkjet printing processes, laser etching processes, lamination processes, etc. may be performed as one of the post-processing processes.

[0119] [Interior materials and seats for vehicles]

[0120] The artificial leather of the present invention has high strength and excellent morphological stability, and is therefore suitable for all uses including industrial material uses such as clothing, sundries, shoes and bags, vehicle interior materials, seats, CD cases, DVD cases, polishing pad substrates, various polishing cloths and wiping cloths.

[0121] Among them, the vehicle interior material made of the above-mentioned artificial leather is particularly preferred because it can reduce the environmental load and has the characteristics of a beautiful and high-grade appearance and mechanical properties at a high level. As such a vehicle interior material, for example, it is more preferred that at least a part of the steering wheel, horn switch, shift lever head, dashboard, instrument panel, glove box, floor carpet, foot mat, roof lining, sun visor, auxiliary handle, etc. of the car is the above-mentioned artificial leather. It should be noted that the "vehicle" in the present invention is headed by automobiles, aircraft, railway vehicles, and ships, and also includes vehicles such as carriages, cars, and rickshaws, as well as excavators, cranes, tractors, combine harvesters, etc., which can carry people and animals and move. Part of industrial machinery, construction machinery, and agricultural machinery.

[0122] Alternatively, seats made of the aforementioned artificial leather can also particularly play a role in reducing environmental load and achieving both beautiful and high-grade appearance and mechanical properties at a high level, so they are also preferred. As such a seat, it is more preferred that at least a portion of the surface material of the headrest, seat surface, armrest, footrest, etc., such as the portion in direct contact with the seated person, is made of the aforementioned artificial leather. Of course, the seat of the present invention can be used not only for vehicles such as automobiles, aircraft, railway vehicles, and ships, but also for home use, office use, and store use. It should be noted that the "seat" referred to in the present invention also includes chairs, benches, sofas, couches, stools, Japanese chairs, etc.

[0123] Example

[0124] Next, the present invention will be specifically described based on examples. However, the present invention is not limited to these examples. It should be noted that in the measurement of various physical properties, unless otherwise specified, the measurement was performed based on the above-mentioned method.

[0125] [Measurement method]

[0126] (1) Average single fiber diameter of fibers and reinforcing fibers (μm)

[0127] The average single fiber diameter (μm) of the fibers contained as main components of the artificial leather and the average single fiber diameter (μm) of the reinforcing fibers were measured and calculated by the above-mentioned method using a scanning electron microscope "VHX-D510" manufactured by KEYENCE CORPORATION.

[0128] (2) Dispersion state of fibers in artificial leather

[0129] Regarding the evaluation of whether the fibers are dispersed as single fibers in the artificial leather, a 1 cm×1 cm area on the surface of the artificial leather was randomly selected and evaluated by the above method using a scanning electron microscope "VHX-D510" manufactured by KEYENCE CORPORATION.

[0130] (3) Heat of fusion ΔHm (J / g) and half-value width of melting peak (°C) of artificial leather

[0131] The heat of fusion ΔHm (J / g) of the artificial leather was measured and calculated by the above-mentioned method using a differential scanning calorimeter “Q20” manufactured by TA Instruments Japan Co., Ltd.

[0132] (4) Content ratio of polyurethane in artificial leather (mass %)

[0133] The content ratio of polyurethane in artificial leather is measured and calculated by the above-mentioned method.

[0134] (5) Fiber cross-sectional profile (unitless)

[0135] The degree of irregularity of fibers contained as a main component of artificial leather was measured and calculated by the above-mentioned method using a scanning electron microscope "VHX-D510" manufactured by KEYENCE CORPORATION.

[0136] (6) Spinning speed Vs (m / min)

[0137] The spinning speed (m / min) in the region below the inlet when producing artificial leather is measured and calculated by the above-mentioned method.

[0138] (7) Appearance evaluation

[0139] Four panelists evaluated the degree of uneven appearance of the artificial leather sample of 10 cm × 10 cm according to the following five-level criteria. Then, the scores judged by each panelist were summed up as the appearance evaluation of the artificial leather, and 3 points or more were considered as passing. The appearance evaluation of the artificial leather is preferably 3.5 points or more, and more preferably 4 points or more.

[0140] 5 points: There is no unevenness (there is no density of fiber, and there is no light and dark of surface color, either)

[0141] 4 points: Good unevenness (between 5 and 3 points)

[0142] 3 points: The unevenness is moderate (the density of fibers and the shade of color are small but can be observed)

[0143] 2 points: Poor unevenness (between 3 points and 1 point)

[0144] 1 point: Poor unevenness (a lot of fiber density and color tone are observed on the entire surface)

[0145] (8) Tactile evaluation

[0146] Four panelists evaluated the touch of a 10 cm x 10 cm artificial leather sample according to the following five-level criteria. Then, the scores of the panelists were summed up as the touch evaluation of the artificial leather, and 3 points or more were considered acceptable. The touch of the artificial leather is preferably 3.5 points or more, and more preferably 4 points or more.

[0147] 5 points: Touch: Excellent (no bumps and smooth touch)

[0148] 4 points: Touch: Good (between 5 and 3)

[0149] 3 points: Touch: Average (some bumps and unevenness are few but can be felt)

[0150] 2 points: Touch: Poor (between 3 points and 1 point)

[0151] 1 point: Touch: Poor (there are many bumps and uneven areas on the entire surface)

[0152] (9) Wear resistance evaluation

[0153] As a Martindale abrasion tester, "Model 406" manufactured by James H. Heal & Co. was used, and as a standard rubbing cloth, "ABRASTIVE CLOTH SM25" manufactured by James H. Heal & Co. was used. A load equivalent to 12 kPa was applied to a circular artificial leather having a diameter of 38 mm, and the appearance of the sample after rubbing was visually observed under the condition of 20,000 times of abrasion and evaluated. Regarding the evaluation criteria, since the appearance of the circular artificial leather having a diameter of 38 mm did not change at all compared with that before rubbing, the case where the number of pilling was 4 or less was recorded as "qualified", and the case where 5 or more was recorded as "unqualified".

[0154] [Example 1]

[0155] (Network Formation)

[0156] Molten polyethylene terephthalate (homopolymer, intrinsic viscosity: 0.65, containing 0.5 wt% of titanium oxide, referred to as "PET" in Tables 1 and 2 and hereinafter) was ejected from a spinning die having an ejection hole having a hole diameter of 0.10 mm and a perfect circle at a single-hole ejection rate of 0.10 g / min. Then, the polyethylene terephthalate was blown with 15°C air at a flow rate of 30.0 m / min in a region 50 mm to 500 mm from the ejection hole to form a filament, and the filament was pulled with 15°C air at a spinning speed of 4,600 m / min in a region below the inlet. At this time, Vq = 30.0 (m / min), Vs = 4,600 (m / min), and therefore Vq / Vs = 6.5×10 -3 . In addition, the distance between the ejection hole and the inlet is 700 mm. Then, the pulled polyethylene terephthalate is captured on a mesh conveyor under suction, thereby obtaining a net formed of fibers having an average single fiber diameter of 4.5 μm and a cross-sectional profile of 1.00. It should be noted that the fibers are dispersed in the form of single fibers.

[0157] (Formation of Sheet Matrix)

[0158] Next, two layers of the obtained web were prepared, and one layer of woven fabric (type of fiber constituting the reinforcing fiber: filament yarn obtained from polyethylene terephthalate (represented as "FY" in Table 1), twist number: 2,500 T / m) with an average single fiber diameter of 15.0 μm was further inserted therebetween as a layer formed of reinforcing fibers to obtain a laminated sheet. The obtained laminated sheet was subjected to water spunlace (represented as "WJP" in Table 1) four times alternately on the front and back at a pressure of 10 MPa to obtain a sheet substrate.

[0159] (Formation of Sheet Base with Polyurethane)

[0160] Then, a water-dispersible polyurethane liquid obtained from polyether diol and diisocyanate (referred to as "liquid A" in Table 1 and hereinafter) is prepared, and the above-mentioned net, etc. are immersed in the water-dispersible polyurethane liquid. Polyurethane is then imparted by a dry coagulation method in which polyurethane is dried at 120°C, thereby obtaining a sheet substrate with polyurethane having a polyurethane content of 23% by mass.

[0161] (Process of forming and post-processing pile sheet)

[0162] Furthermore, one surface of the polyurethane-attached sheet substrate was ground with sandpaper to perform a napping treatment to form nap on the surface. After the nap sheet was formed, it was post-processed and dyed with disperse dyes at 130° C. using a jet dyeing machine to obtain artificial leather. The results are shown in Table 1.

[0163] [Example 2]

[0164] The results are shown in Table 1.

[0165] [Example 3]

[0166] The results are shown in Table 1.

[0167] [Example 4]

[0168] The results are shown in Table 1, except that the shape of the ejection hole was changed so that the degree of irregularity of the cross section of the fiber was changed from 1.00 to 3.00.

[0169] [Example 5]

[0170] The results are shown in Table 2. An artificial leather was obtained in the same manner as in Example 1 except that polyethylene terephthalate (described as "PET2" in Table 2) not containing titanium oxide was used in (net formation).

[0171] [Example 6]

[0172] The results are shown in Table 2, except that the spinning was performed at a single hole discharge rate of 0.09 g / min and a spinning speed of 4,000 m / min in (web formation) in the same manner as in Example 5 to obtain artificial leather.

[0173] [Example 7]

[0174] The results are shown in Table 2, except that the spinning was performed at a single hole discharge rate of 0.07 g / min and a spinning speed of 3,100 m / min in (web formation) in the same manner as in Example 5 to obtain artificial leather.

[0175] [Example 8]

[0176] The results are shown in Table 2, except that the spinning was performed at a single hole discharge rate of 0.13 g / min and a spinning speed of 6,000 m / min in (web formation) in the same manner as in Example 5 to obtain artificial leather.

[0177] [Example 9]

[0178] The results are shown in Table 2, except that the spinning was performed by ejecting from the ejection holes of the spinneret having a hole diameter of 0.20 mm and a perfect circle.

[0179] [Example 10]

[0180] The results are shown in Table 2, except that the spinning was performed by ejecting from the ejection holes of the spinneret having a hole diameter of 0.30 mm and a perfect circle.

[0181] [Example 11]

[0182] The results are shown in Table 3, except that spinning was performed by forming filaments while blowing air in a region 5 mm to 40 mm from the ejection hole.

[0183] [Example 12]

[0184] The results are shown in Table 3, except that spinning was performed by forming filaments while blowing air in a region 150 mm to 600 mm from the ejection hole.

[0185] [Example 13]

[0186] The results are shown in Table 3, except that spinning was performed in the same manner as in Example 5 with the distance between the ejection hole and the introduction port being 1,200 mm.

[0187] [Example 14]

[0188] The results are shown in Table 3, except that the spunlace was performed at a pressure of 25 MPa and polyurethane was not added in the same manner as in Example 5.

[0189] [Example 15]

[0190] The results are shown in Table 3, except that the raising treatment was not performed in the (forming of the pile sheet and post-processing step) in the same manner as in Example 5, an artificial leather having no pile on any surface was obtained.

[0191] [Example 16]

[0192] (Process of forming and post-processing pile sheet)

[0193] The polyurethane-coated sheet substrate obtained in the same manner as in Example 5 was passed through a press roll heated to 90° C. to perform a smoothing treatment. 2 An ester-based two-component polyurethane solution was applied, dried, and then molded at 160°C using an embossing roller having a leather-like texture, and then dyed at 130°C using a liquid jet dyeing machine using disperse dyes as a post-processing to obtain an artificial leather having no tuft on any surface. The results are shown in Table 3.

[0194] [Comparative Example 1]

[0195] In (net formation), the same polyethylene terephthalate as in Example 1 was used, and the polyethylene terephthalate was blown with air at 15°C at a flow rate of 30.0 m / min in a region 50 mm to 500 mm from the ejection hole to form a filament, and after roller drawing at a spinning speed of 1,600 m / min, a fiber having an average single fiber diameter of 4.5 μm and a cross-sectional profile of 1.00 was produced under a stretching ratio of 2.9 times. The fiber was cut into a fiber length of 5 mm, dispersed in water, and a net for the surface layer and the back layer was made by a papermaking method. The same operation as in Example 1 was performed except that the above-mentioned operation was performed to obtain an artificial leather. It should be noted that the fiber was dispersed in the form of a single fiber. The results are shown in Table 1.

[0196] [Comparative Example 2]

[0197] (Network Formation)

[0198] Polyethylene terephthalate as the island component and polystyrene as the sea component (referred to as "PS" in Table 1) were melted separately by an extruder and weighed in such a way that the mass ratio of the island component to the sea component was 80:20. The sea-island type composite fiber was ejected at a single-hole ejection rate of 2.00 g / min from the ejection hole of the spinneret capable of forming a cross section of 16 island components with uniform cross-sectional areas distributed in the sea component. Thereafter, air below 15°C was blown at a speed of 0.5 m / sec for the molten island component and the sea component in a region 100 to 500 mm from the ejection hole, and the fiber was pulled with air at 15°C so that the spinning speed became 4,600 m / min. At this time, Vq = 30.0 (m / min), Vs = 4,600 (m / min), and therefore Vq / Vs = 6.5×10 -3 . In addition, the distance between the ejection hole and the inlet is 700 mm. Then, the pulled composite fibers are captured on a mesh conveyor under suction to obtain a composite fiber web. It should be noted that the fibers are not dispersed in the form of single fibers, and many bundles of fibers can be seen.

[0199] (Formation of sheet matrix, formation of sea-free sheet)

[0200] Here, a composite fiber web is stacked on the front and back of a scrim with a single fiber diameter of 15 μm, and needle punched to obtain a sheet substrate. The obtained sheet substrate is immersed in trichloroethylene to dissolve and remove the sea component, and a sea-free sheet is obtained by entanglement of a nonwoven fabric formed of fibers with an average single fiber diameter of 4.5 μm and a cross-sectional profile of 1.00.

[0201] (Formation of Sheet Base with Polyurethane)

[0202] The water-dispersible polyurethane liquid (liquid A) used in Example 1 was applied to the sea-removed sheet obtained in this way by an immersion / kneading method so that 3% by mass of a polyurethane resin was attached.

[0203] (Process of forming and post-processing pile sheet)

[0204] Raising treatment and post-processing (dyeing) were performed in the same manner as in Example 1 to obtain artificial leather. The results are shown in Table 1.

[0205] [Comparative Example 3]

[0206] In (net formation), polyethylene terephthalate (PET) was used as in Example 1, and a net of fibers having an average single fiber diameter of 4.5 μm and a cross-sectional profile of 1.00 was obtained by melt-blowing with hot air at 320°C and 0.10 MPa. This was used as a net for the surface layer and the back layer, and artificial leather was obtained in the same manner as in Example 1. It should be noted that the fibers were dispersed in the form of single fibers. The results are shown in Table 2.

[0207] [Table 1]

[0208]

[0209] As shown in Table 1, Examples 1 to 4 had both high appearance, quality, and abrasion resistance used as an index of physical properties. On the other hand, Comparative Examples 1 and 2 had poor appearance and touch.

[0210] [Table 2]

[0211]

[0212] As shown in Table 2, Examples 5 to 10 had high levels of appearance, quality, and wear resistance used as an index of physical properties. On the other hand, Comparative Example 3 was inferior in appearance, touch, and wear resistance.

[0213] [Table 3]

[0214]

[0215] As shown in Table 3, Examples 11 to 16 have both appearance, quality, and abrasion resistance used as an index of physical properties at a high level.

[0216] Description of Reference Numerals

[0217] 1: Spray hole

[0218] 2: Arrow indicating the blowing of gas

[0219] 3: Arrows representing gas-based traction

[0220] 4: The distance from the outlet to the location where the gas is blown

[0221] 5: Distance from the ejection hole to the inlet

[0222] 6: Hopper

[0223] 7: Extruder

[0224] 8: Gear pump

[0225] 9: Spinneret

[0226] 10: Gas supply means

[0227] 11: Silk strips

[0228] 12: Traction means

[0229] 13: Net

[0230] 14: Means of transport

Claims

1. An artificial leather comprising fibers formed from a polyester resin and having an average single fiber diameter of 2.0 μm to 7.0 μm as main components, wherein the fibers are long fibers and dispersed in the form of single fibers, the heat of fusion ΔHm of the artificial leather is from 10 J / g to 100 J / g, and the half-value width of the melting peak is from 9°C to above.

2. The artificial leather according to claim 1, which has a pile on at least one surface. 3 . The artificial leather according to claim 1 , further comprising as a component a layer formed of reinforcing fibers having an average single fiber diameter of 5.0 μm to 25.0 μm.

4. The artificial leather according to claim 1 or 2, further comprising polyurethane as a constituent element, wherein the content of the polyurethane is 5 mass % or more and 50 mass % or less.

5. The artificial leather according to claim 1 or 2, wherein: The fiber has a cross-sectional profile of not less than 1.00 and not more than 1.

15.

6. The method for producing artificial leather according to claim 1, comprising the steps of: after a molten polyester resin is ejected from a spray hole of a spinneret at a single-hole ejection rate of 0.05 g / min to 0.30 g / min, a gas at a temperature of -15°C to 50°C is blown to the polyester resin in at least a portion of an area within 200 mm from the spray hole to form filaments, and at least in an inlet, the filaments are pulled by a gas at a temperature of -15°C to 50°C at a spinning speed Vs (m / min) of 3,000 m / min to 7,000 m / min to obtain a web formed by fibers having an average single fiber diameter of 2.0 μm to 7.0 μm.

7. The method for producing artificial leather according to claim 6, wherein: The ratio Vq / Vs of the gas flow rate Vq (m / min) and the spinning speed Vs (m / min) when the gas is blown is set to 3×10 -3 Above 30×10 -3 the following.

8. The method for producing artificial leather according to claim 6 or 7, wherein: The distance between the ejection hole and the introduction port is set to be 100 mm or more and 3,000 mm or less.

9. The method for producing artificial leather according to claim 6 or 7, wherein: The diameter of the ejection hole is not less than 0.05 mm and not more than 0.30 mm.

10. A vehicle interior material comprising the artificial leather according to claim 1.

11. A seat made of the artificial leather according to claim 1.

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