Artificial leather, method for manufacturing the same, and artificial leather base material

Abstract

The present invention addresses the problem of providing an artificial leather that exhibits excellent flame resistance while maintaining moderate ventilation and soft texture, and that offers an elegant appearance and a feel similar to natural suede, said artificial leather being configured to: have an elastic polymer body and an interlaced fiber body which comprises ultrafine fibers having an average monofilament diameter of 0.1-10 μm; have a napped surface having a nap on one surface and have a flame-resistant surface containing a flame retardant on the other surface; and fulfill requirement 1 and requirement 2 indicated below. Requirement 1: At least the flame-resistant surface having a plurality of openings formed therein. Requirement 2: The flame retardant having a tackiness of 0.1-2.0 N / cm2.<sp / >

Description

Technical Field

[0001] The present invention relates to an artificial leather composed of a fiber complex containing ultrafine fibers, a polymer elastomer, and a functional agent (such as a flame retardant), which has excellent flame retardancy while having appropriate breathability and a soft texture, and has a touch like natural suede and an elegant appearance. Further, it relates to an artificial leather substrate having good formability of openings for obtaining the artificial leather.

Background Art

[0002] Conventionally, artificial leather composed of a fiber complex made of ultrafine fibers and a polymer elastomer and having pile has characteristics such as high breathability, durability, and quality uniformity, which are superior compared to natural leather, and is used not only as a material for clothing but also in various fields such as interior materials for public transportation such as airplanes, ships, and railway vehicles, interior materials for vehicles, interior materials, building materials, and miscellaneous goods.

[0003] In the above-mentioned fields, artificial leather is often required to have a high level of flame retardant performance, and in fields where flame retardancy is required, it is common to add a flame retardant to the artificial leather. Among them, in interior materials for vehicles, especially in order to cope with the ventilation system, appropriate breathability is required by controlling the density and material composition of the artificial leather and the openings.

[0004] By the way, in order to impart flame retardancy to artificial leather, methods such as imparting a flame retardant to ultrafine fibers, imparting a flame retardant to the whole artificial leather, or applying and imparting a flame retardant to one side of the artificial leather are adopted.

[0005] However, the artificial leather obtained by these methods has different mechanisms of developing flame retardancy between the polymer elastomer such as polyurethane constituting it and the ultrafine thermoplastic synthetic fibers constituting the non-woven fabric, woven fabric, or knitted fabric, and it is known that it is very difficult to make the whole artificial leather flame retardant.

[0006] To address these flame retardancy challenges, there are proposals such as using an organophosphorus copolymer polyester for the ultrafine fibers of artificial leather (see, for example, Patent Document 1), using a polyurethane polymer elastic body copolymerized with an organophosphorus component for the polymer elastic body of artificial leather (see, for example, Patent Document 2), or attaching and exhausting a diarylphosphoamide-based flame retardant to the ultrafine fibers (see, for example, Patent Document 3).

[0007] Alternatively, methods have been proposed for laminating and integrating a substrate made of flame-retardant heat-resistant fibers on the back surface (see, for example, Patent Document 4), or for partially applying a flame retardant to the back surface of artificial leather so that the area ratio is 60-90% in order to ensure a certain degree of breathability (see, for example, Patent Document 5), and for forming ventilation holes that penetrate the artificial leather (see, for example, Patent Document 6). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2002-115183 [Patent Document 2] Japanese Patent Publication No. 2002-201574 [Patent Document 3] Japanese Patent Publication No. 2012-229508 [Patent Document 4] Japanese Patent Publication No. 2014-25156 [Patent Document 5] Special Publication No. 2013-520581 [Patent Document 6] International Publication No. 2014 / 097999 [Overview of the project] [Problems that the invention aims to solve]

[0009] In the technology disclosed in Patent Document 1, the copolymerization of organophosphorus components compared to polyester commonly used in ultrafine fibers results in reduced spinnability and dyeability during manufacturing. Furthermore, the yarn strength of the ultrafine fibers and the abrasion fastness of the artificial leather are reduced, making it difficult to use in applications requiring high lightfastness and high abrasion resistance.

[0010] In the technology disclosed in Patent Document 2, an organophosphorus component is copolymerized with the polyurethane component, which is an important constituent material for giving artificial leather strength and texture without deterioration over time. This design results in a decrease in texture and durability compared to ordinary polyurethane.

[0011] In the technology disclosed in Patent Document 3, if the diarylphosphoamide flame retardant is applied without using a binder, the flame retardant may fall off during use, resulting in unstable flame retardancy. On the other hand, if it is applied with a binder, the surface of the artificial leather becomes hard to the touch. In addition, as disclosed in the background art of Patent Document 3, when a water-soluble flame retardant such as guanidine phosphate is applied to the entire artificial leather, after the pile surface absorbs moisture and then dries, the guanidine phosphate dissolves due to the moisture and migrates to the surface, causing a phenomenon known as "edge staining," which forms ring-shaped stains and significantly impairs the aesthetic appeal of the artificial leather.

[0012] In technologies such as those disclosed in Patent Document 4, it is necessary to use a sufficient amount of flame-retardant heat-resistant fibers to ensure a certain level of flame retardancy, which reduces the density of the interwoven structure of the artificial leather, and can easily impair its elegant appearance and flexible texture. Methods of inserting and interwoven the fibers internally, or methods of blending flame-retardant heat-resistant fibers into the constituent fibers, have similar problems.

[0013] In the technology disclosed in Patent Document 5, the flame retardant is applied in a dot pattern, so sufficient flame retardancy is not obtained, and the spare artificial leather does not have sufficient breathability. As a result, it is not possible to achieve both the density required for an elegant appearance and the breathability necessary to accommodate, for example, a ventilation system.

[0014] Furthermore, in technologies such as those disclosed in Patent Document 6, the waste material after punching tends to clog the sheet or punching roll during the perforation process, making mass production difficult.

[0015] In summary, the technologies disclosed in Patent Documents 1 to 6 have not been able to provide artificial leather that combines flame retardancy with other important properties (in particular, moderate breathability, a soft texture like natural suede, and an elegant appearance) in an artificial leather composed of a fiber entanglement body made of ultrafine fibers that are difficult to make flame-retardant and a polymer elastic body.

[0016] Therefore, the present invention has been made in view of the above circumstances, and its objective is to provide an artificial leather that has moderate breathability and a flexible texture while being highly functional (flame retardant, etc.), and having a touch and elegant appearance similar to natural suede. Furthermore, it is also objective to provide an artificial leather base material that has good opening formation properties for obtaining the said artificial leather. [Means for solving the problem]

[0017] In order to achieve the above objectives, the inventors conducted extensive research and found that in artificial leather consisting of an ultrafine fiber entanglement, a polymer elastic body, and a functional agent (flame retardant, etc.), by specifying the form of the functional agent (flame retardant, etc.) and the tackiness of the functional agent (flame retardant, etc.) within a specific range, it is possible to provide artificial leather that has good formability even if an opening is provided in the artificial leather, and that achieves both functionality (flame retardancy, etc.) and other important properties.

[0018] This invention was completed based on these findings, and according to this invention, the following inventions are provided.

[0019] The artificial leather of the present invention comprises a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, wherein one surface is a pile surface having a raised nap, and the other surface is a flame retardant surface having a flame retardant, and satisfies the following requirements 1 and 2. Requirement 1: The flame-retardant surface has at least a plurality of openings. Requirement 2: The tackiness of the flame retardant is 0.1 N / cm². 2 More than 2.0N / cm 2 The following applies:

[0020] According to a preferred embodiment of the artificial leather of the present invention, the opening ratio of the flame-retardant surface is 1% or more and 40% or less.

[0021] According to a preferred embodiment of the artificial leather of the present invention, the artificial leather has a plurality of openings in the pile surface and the flame-retardant surface, and at least a portion of the openings are through-openings that penetrate from the pile surface to the flame-retardant surface.

[0022] According to a preferred embodiment of the artificial leather of the present invention, the fiber entanglement body is formed by integrating the fiber entanglement body made of the ultrafine fibers with a woven or knitted fabric (a).

[0024] According to a preferred embodiment of the artificial leather of the present invention, the ratio of the flame retardant in the thickness direction satisfies the following formula. 0.001 ≤ W / W0 ≤ 0.7 Here, W is the thickness (mm) from the flame-retardant surface where the flame retardant is present, and W0 is the total thickness (mm) of the artificial leather.

[0025] According to a preferred embodiment of the artificial leather of the present invention, the flame retardant includes a phosphorus-based compound.

[0026] According to a preferred embodiment of the artificial leather of the present invention, the density of the fiber entanglement containing the polymeric elastic material is 0.20 g / cm³. 3 More than 0.50g / cm 3 The following applies:

[0027] Furthermore, the present invention relates to a method for manufacturing artificial leather, in which a pile-like sheet made of a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm and a polymer elastic body is applied to one surface of the sheet-like material with a tackiness of 0.1 N / cm². 2 More than 2.0N / cm 2 A flame retardant is applied to form a flame retardant surface, and at least a plurality of openings are provided on the flame retardant surface.

[0028] The artificial leather base material of the present invention comprises a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm, and a polymer elastic body, wherein one surface is a pile surface having a raised nap, and the other surface is a functional surface having a functional agent, and the tackiness of the functional agent is 0.1 N / cm 2 More than 2.0N / cm 2 The following applies. Note that the artificial leather base material can be modified to form the artificial leather of the present invention by creating openings, but it can also be used as artificial leather itself.

[0029] The artificial leather base material of the present invention comprises a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, wherein one surface is a pile surface having a piled surface and the other surface is a functional surface having a functional agent, the dynamic friction coefficient of the functional surface is 0.15 or more and 0.60 or less, and the rigidity of the artificial leather base material is 30 mm or more and 150 mm or less.

[0030] The artificial leather substrate of the present invention comprises a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, wherein one surface is a pile surface having raised fibers and the other surface is a functional surface having a functional agent, and the amount of the functional agent attached is 2 to 30% by mass relative to the artificial leather substrate. [Effects of the Invention]

[0031] According to the present invention, it is possible to obtain artificial leather that has appropriate breathability and a soft texture, is excellent in functionality (such as flame retardancy), has a touch like natural suede, and has an elegant appearance. Further, it is possible to obtain an artificial leather substrate that has good formability of openings for obtaining the artificial leather.

Mode for Carrying Out the Invention

[0032] The artificial leather of the present invention has a fiber complex body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, and one surface is a pilose surface having pile, and the other surface is a flame-retardant surface having a flame retardant, and satisfies the following requirements 1 and requirement 2. Requirement 1: It has a plurality of openings at least on the flame-retardant surface. Requirement 2: The tackiness of the flame retardant is 0.1 N / cm 2 or more and 2.0 N / cm 2 or less.

[0033] The ultrafine fibers contained in the fiber complex body are preferably 60% or more, more preferably 80% or more, by weight ratio.

[0034] The artificial leather substrate of the present invention has a fiber complex body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, and one surface is a pilose surface having pile, and the other surface is a functional surface having a functional agent, and the tackiness of the functional agent is 0.^{} 2 1 N / cm or more and 2.0 N / cm 2 or less.

[0035] The artificial leather substrate of the present invention has a fiber complex body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, and one surface is a pilose surface having pile, and the other surface is a functional surface having a functional agent, and the kinetic friction coefficient of the functional surface is 0.15 or more and 0.60 or less, and the rigidity-flexibility of the artificial leather is 30 mm or more and 150 mm or less.

[0036] The artificial leather substrate of the present invention comprises a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm, and a polymer elastic body, wherein one surface is a pile surface having a raised nap, and the other surface is a functional surface having a functional agent, and the amount of the functional agent attached is 2 to 30% by mass relative to the artificial leather substrate. These components will be described in detail below, but the present invention is not limited in any way to the scope described below, as long as it does not exceed the gist of the invention.

[0037] [Fiber entanglement] The fibrous composite constituting the artificial leather of the present invention comprises ultrafine fibers, with an average single fiber diameter of 0.1 μm to 10 μm. By setting the average single fiber diameter of the ultrafine fibers to 0.1 μm or more, preferably 1.5 μm or more, excellent effects are obtained in terms of color development after dyeing, lightfastness and friction fastness, and stability during spinning, resulting in artificial leather with sufficient strength for practical use. On the other hand, by setting the diameter to 10.0 μm or less, preferably 6.0 μm or less, and more preferably 4.5 μm or less, an artificial leather with excellent surface quality that is flexible, dense, and soft to the touch can be obtained.

[0038] In this invention, the average single fiber diameter of ultrafine fibers is calculated by taking a scanning electron microscope (SEM) photograph of the cross-section of artificial leather, randomly selecting 10 ultrafine fibers that are circular or nearly circular in shape, measuring the single fiber diameter, calculating the arithmetic mean of the 10 fibers, and rounding to two decimal places. However, if ultrafine fibers with an irregular cross-section are used, the single fiber diameter is determined by first measuring the cross-sectional area of ​​the single fiber and calculating the diameter when the cross-section is considered to be circular.

[0039] As the ultrafine fibers of the fibrous entanglement constituting the artificial leather of the present invention, various synthetic fibers can be used, including polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylenedimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, and polyethylene-1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate, polyamides such as polyamide 6 and polyamide 66, and polymers such as acrylic polyethylene and polypropylene. Among these, polyester fibers made from polymers such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate are preferred due to their excellent strength, dimensional stability, lightfastness, and dyeability. Furthermore, ultrafine fibers of different materials can be mixed in the fibrous entanglement, as long as the objectives of the present invention are not impaired.

[0040] While a round cross-section is preferable for the cross-sectional shape of ultrafine fibers from the viewpoint of ease of processing and operation, other irregular cross-sectional shapes such as elliptical, flat, triangular, sector-shaped, cross-shaped, hollow, Y-shaped, T-shaped, and U-shaped can also be adopted.

[0041] Depending on the purpose, the ultrafine fibers constituting the fiber entanglement can be supplemented with inorganic particles such as titanium dioxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents.

[0042] In order to achieve excellent deep color development in the present invention, the resin constituting the ultrafine fibers may be a polyester resin, and the polyester resin may contain a pigment with an average particle size of 0.05 μm or more and 0.20 μm or less. The particle size referred to here is the particle size when the pigment is present in the ultrafine fibers, and is generally called the secondary particle size. By setting the average particle size to 0.05 μm or more, preferably 0.07 μm or more, the pigment is held inside the ultrafine fibers, so that it does not fall off the ultrafine fibers. Furthermore, by setting it to 0.20 μm or less, preferably 0.18 μm or less, and more preferably 0.16 μm or less, excellent stability during spinning and yarn strength are obtained. The average particle size shall be calculated by the following method. (1) Prepare ultrathin sections with a thickness of 5-10 μm in the cross-sectional direction of a plane perpendicular to the longitudinal direction of the ultrafine fiber. (2) Observe the fiber cross-section in the ultrathin section at 10,000x magnification using a transmission electron microscope (TEM). (3) Using image analysis software, measure the equivalent circular diameter of pigment particles contained within a 2.3 μm × 2.3 μm field of view of the observed image at 20 points. If there are fewer than 20 pigment particles contained within a 2.3 μm × 2.3 μm field of view, measure the equivalent circular diameter of all present pigment particles. (4) Calculate the average value (arithmetic mean) for the 20 measured particle sizes.

[0043] In order to achieve excellent dark color development in the present invention, when the resin constituting the ultrafine fibers is a polyester resin and pigment is included in the polyester resin, it is preferable that the pigment content in the polyester resin forming the ultrafine fibers be 0.5% by mass or more and 2.0% by mass or less relative to the mass of the ultrafine fibers. By setting the pigment ratio to 0.5% by mass or more, preferably 0.7% by mass or more, and more preferably 0.9% by mass or more, excellent dark color development is achieved. By setting the pigment ratio to 2.0% by mass or less, preferably 1.8% by mass or less, and more preferably 1.6% by mass or less, an artificial leather with high physical properties such as strength can be obtained. As the pigment, carbon-based black pigments such as carbon black and graphite, or oxide-based black pigments such as triiron tetroxide and copper-chromium composite oxides can be used. From the viewpoint of easily obtaining fine particle sizes and excellent dispersibility in polymers, it is preferable that the pigment be carbon black. As chromatic fine particle oxide pigments, known pigments close to the target color can be used, such as iron oxyhydroxide (e.g., "TM Yellow 8170" manufactured by Dainichi Seika Co., Ltd.), iron oxide (e.g., "TM Red 8270" manufactured by Dainichi Seika Co., Ltd.), and cobalt aluminate (e.g., "TM Blue 3490E" manufactured by Dainichi Seika Co., Ltd.).

[0044] The artificial leather of the present invention has a fiber entanglement made of ultrafine fibers as one of its components. Examples of fiber entanglements include woven fabrics, knitted fabrics, nonwoven fabrics, etc., and furthermore, these fiber entanglements may contain a polymeric elastic material inside or outside them, and can be appropriately selected according to the cost and characteristics required for each application and purpose. In terms of cost, woven fabrics and knitted fabrics are preferably used, while in terms of a rich texture and quality due to fine pile, nonwoven fabrics and fiber entanglements filled with polymeric elastic materials are preferably used.

[0045] When woven or knitted fabrics are used as the fiber entanglement, examples of woven fabrics include plain weave, twill weave, satin weave, and various fabrics based on these weave structures. As for knitted fabrics, warp knitting, weft knitting (represented by tricot knitting), lace knitting, and various knitted fabrics based on these weave structures can all be used.

[0046] When nonwoven fabrics are used as the fiber entanglement material, all nonwoven fabrics expressed in various categories, such as general short-fiber nonwoven fabrics, long-fiber nonwoven fabrics, needle-punched nonwoven fabrics, papermaking nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, and electrospinned nonwoven fabrics, can be applied. In this case, nonwoven fabrics are preferred in terms of their substantial texture and the quality due to their fine pile.

[0047] Including a polymeric elastic material inside or outside the fiber entanglement is more preferable in terms of improving the durability and abrasion resistance of the artificial leather. In particular, including a polymeric elastic material inside the fiber entanglement is preferable from the viewpoint of flexibility.

[0048] Furthermore, in the artificial leather of the present invention, it is preferable to intertwine and integrate the fiber entanglement body and the woven or knitted fabric (a) in order to have excellent mechanical strength. More preferably, the fiber entanglement body is a nonwoven fabric and contains the woven or knitted fabric (a) inside it. Even more preferably, the fiber entanglement body is a nonwoven fabric and the woven or knitted fabric (a) is a woven fabric, which provides an optimal balance of appearance, flexibility, and strength.

[0049] In the woven or knitted fabric (a) that is integrated with the fiber entanglement, synthetic fibers made of polyester, polyamide, polyethylene, or polypropylene, or copolymers thereof, are preferably used as the yarn constituting the woven or knitted fabric (a). Among these, synthetic fibers made of polyester, polyamide, and copolymers thereof can be used alone, in combination, or in mixture. Furthermore, as the yarn constituting the woven or knitted fabric (a), filament yarn, spun yarn, and blended yarn of filaments and staple fibers can be used. From the viewpoint of durability, and especially mechanical strength, it is more preferable to use multifilaments made of polyester resin or polyamide resin.

[0050] By setting the average single fiber diameter of the fibers constituting the woven fabric (a) to 50.0 μm or less, more preferably 15.0 μm or less, and even more preferably 13.0 μm or less, not only is it possible to obtain artificial leather with excellent flexibility, but even when the fibers of the woven fabric are exposed on the surface of the artificial leather, the difference in hue between them and the ultrafine fibers containing pigment after dyeing is reduced, so the uniformity of the hue on the surface is not impaired. On the other hand, by setting the average single fiber diameter of the fibers constituting the woven fabric (a) to 1.0 μm or more, more preferably 8.0 μm or more, and even more preferably 9.0 μm or more, the morphological stability of the product as artificial leather is improved. The average single fiber diameter of the fibers constituting the woven fabric (a) is calculated by taking a scanning electron microscope (SEM) photograph of the cross-section of the artificial leather, randomly selecting 10 fibers constituting the fabric, measuring the single fiber diameter of those fibers, calculating the arithmetic mean of the 10 fibers, and rounding to the second decimal place. When the fibers constituting the woven or knitted fabric (a) are multifilaments, the total fineness of the multifilaments is measured by "8.3 Fineness" of "8.3.1 Total Fineness b) Method B (Simplified Method)" in JIS L1013:2010 "Test Methods for Chemical Fiber Filament Yarns," and is preferably 30 dtex or more and 170 dtex or less. By setting the total fineness of the yarn constituting the woven or knitted fabric (a) to 170 dtex or less, an artificial leather with excellent flexibility can be obtained. On the other hand, setting the total fineness to 30 dtex or more is preferable not only because it improves the morphological stability of the product as artificial leather, but also because, when the fiber entanglement is made into a nonwoven fabric, the fibers constituting the woven or knitted fabric (a) are less likely to be exposed on the surface of the artificial leather when the woven or knitted fabric (a) is entangled and integrated by needle punching or the like. When the woven or knitted fabric (a) is a woven fabric, it is preferable that the total fineness of the warp and weft multifilaments be the same. Furthermore, it is preferable that the number of twists in the yarn constituting the aforementioned fabric be between 1000 T / m and 4000 T / m.By setting the twist count to 4000 T / m or less, more preferably 3500 T / m or less, and even more preferably 3000 T / m or less, an artificial leather with excellent flexibility can be obtained. By setting the twist count to 1000 T / m or more, more preferably 1500 T / m or more, and even more preferably 2000 T / m or more, it is possible to prevent damage to the fibers constituting the fabric when the nonwoven fabric and the woven fabric are intertwined and integrated by needle punching or the like, and the artificial leather will have excellent mechanical strength, which is preferable.

[0051] The woven or knitted fabric (a) may also be a woven or knitted fabric containing composite fibers (hereinafter sometimes referred to as side-by-side or similar composite fibers) in which two or more polymers are compounded in a side-by-side or eccentric core-sheath type. For example, in side-by-side or similar composite fibers consisting of two or more polymers with different intrinsic viscosity (IV), stress concentration on the high-viscosity side during stretching causes different internal strains between the two components. Due to this internal strain, the high-viscosity side shrinks significantly due to the difference in elastic recovery rate after stretching and the difference in thermal shrinkage during the heat treatment process, causing strain within the single fiber and resulting in three-dimensional coil-type crimping. This three-dimensional coil-type crimping gives rise to the stretchability of the artificial leather.

[0052] When the interwoven fibers are formed into a nonwoven fabric, a uniform and elegant appearance and texture can be obtained when the surface is napped. Nonwoven fabrics can take two forms: long-fiber nonwoven fabrics, which are mainly composed of filaments, and short-fiber nonwoven fabrics, which are mainly composed of fibers 100 mm or less in length. When a long-fiber nonwoven fabric is used as the fibrous base material, it is preferable because it can produce artificial leather with excellent strength. On the other hand, when a short-fiber nonwoven fabric is used, it is possible to have more fibers oriented in the thickness direction of the artificial leather compared to the case of a long-fiber nonwoven fabric, and the surface of the artificial leather can be made to have a high density when napped.

[0053] When using short-fiber nonwoven fabric, the fiber length of the ultrafine fibers is preferably 25 mm to 90 mm. By setting the fiber length to 90 mm or less, more preferably 80 mm or less, and even 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 even more preferably 40 mm or more, an artificial leather with excellent abrasion resistance can be obtained.

[0054] The basis weight of the fiber entanglement material, which is made up of ultrafine fibers and constitutes the artificial leather according to the present invention, was measured according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General nonwoven fabric testing methods", and was 50 g / m². 2 More than 600g / m 2 The following range is preferable: The basis weight of the nonwoven fabric is 50 g / m². 2 Above, a comfortable 100g / m 2 By doing so, it is possible to produce a high-quality artificial leather with a substantial feel and excellent texture. On the other hand, 600g / m 2 More preferably, 450 g / m² 2 By doing the following, a flexible artificial leather with excellent moldability can be obtained. Even when woven or knitted fabrics (a) are intertwined and integrated, the basis weight of the intertwined fiber body is preferably within the aforementioned basis weight range.

[0055] [Polymer elastic material] The artificial leather of the present invention contains a polymeric elastic body. Preferably, the polymeric elastic body is contained within the fiber entanglement. By containing a polymeric elastic body, the flexibility, dimensional stability, and abrasion resistance of the artificial leather are improved. Unlike the functional agents (flame retardants, etc.) described later, the polymeric elastic body must serve as a binder for the fiber entanglement.

[0056] As the aforementioned polymeric elastic material, polyurethane, styrene-butadiene rubber (SBR), nitrile rubber (NBR), and acrylic resin can be used, and among these, polyurethane is preferably used as the main component. By using polyurethane, it is possible to obtain artificial leather that has a touch and elegant appearance similar to natural suede, as well as physical properties that can withstand actual use.

[0057] The polyurethane forming the polymeric elastic body preferably contains a black pigment (b) with an average particle size of 0.05 μm or more and 0.20 μm or less, and a coefficient of variation (CV) of 75% or less.

[0058] The particle size referred to here is the particle size of the black pigment (b) when it is present in a polymeric elastic material, and is generally called the secondary particle size.

[0059] By setting the average particle size to 0.05 μm or more, preferably 0.07 μm or more, the black pigment (b) is held within the polymer elastic material, thereby suppressing its shedding from the ultrafine fibers. Furthermore, by setting the particle size to 0.20 μm or less, preferably 0.18 μm or less, and more preferably 0.16 μm or less, excellent dispersibility is achieved when impregnating the polymer elastic material.

[0060] When the coefficient of variation (CV) of particle size is 75% or less, preferably 65% ​​or less, more preferably 60% or less, even more preferably 55% or less, and most preferably 50% or less, the particle size distribution becomes smaller, suppressing the shedding of small particles from the surface of the polymer elastic material and the precipitation of significantly aggregated particles into the impregnation tank.

[0061] In this invention, the average particle size and coefficient of variation (CV) are calculated by the following method. (1) Prepare ultrathin sections with a thickness of 5-10 μm in the cross-sectional direction of a surface perpendicular to the longitudinal direction of the artificial leather. (2) Observe the cross-section of the polymeric elastic material in the ultrathin section at 10,000x magnification using a transmission electron microscope (TEM). (3) Using image analysis software, measure the equivalent circular diameter of the black pigment (b) particles contained within a 2.3 μm × 2.3 μm field of view of the observed image at 20 points. If there are fewer than 20 black pigment (b) particles contained within a 2.3 μm × 2.3 μm field of view, measure the equivalent circular diameter of all present black pigment (b) particles. (4) For the 20 measured particle sizes, calculate the average value (arithmetic mean) and the coefficient of variation (CV). In this invention, the coefficient of variation shall be calculated using the following formula. The coefficient of variation (%) of particle size = (standard deviation of particle size) / (arithmetic mean of particle size) × 100.

[0062] In the present invention, the black pigment (b) can be a carbon-based black pigment such as carbon black or graphite, or an oxide-based black pigment such as triiron tetroxide or a copper-chromium composite oxide. From the viewpoint of easily obtaining fine particle sizes and having excellent dispersibility in polymers, the black pigment is preferably carbon black.

[0063] The polyurethane used in this invention can be either an organic solvent-based polyurethane used in a dissolved state in an organic solvent, or a water-dispersible polyurethane used in a dispersed state in water. Furthermore, the polyurethane used in this invention is preferably a polyurethane obtained by the reaction of a polymer diol, an organic diisocyanate, and a chain extender.

[0064] Examples of the polymer diols used include polycarbonate-based diols, polyester-based diols, polyether-based diols, silicone-based diols, and fluorine-based diols. Copolymers combining these can also be used. Among these, polycarbonate-based diols are preferred from the viewpoint of hydrolysis resistance and abrasion resistance.

[0065] The above-mentioned polycarbonate diols can be produced by transesterification of alkylene glycol and carbonate ester, or by reaction of phosgene or chlorformate ester with alkylene glycol.

[0066] Examples of alkylene glycols include linear alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol; branched alkylene glycols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanediol; aromatic diols such as bisphenol A; glycerin; trimethylolpropane; and pentaerythritol. In the present invention, either polycarbonate diols obtained from individual alkylene glycols or copolymerized polycarbonate diols obtained from two or more alkylene glycols can be used.

[0067] Furthermore, examples of polyester diols include polyester diols obtained by condensing various low molecular weight polyols with polybasic acids.

[0068] Examples of low molecular weight polyols include one or more selected from ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, and cyclohexane-1,4-dimethanol.

[0069] In addition, adducts obtained by adding various alkylene oxides to bisphenol A can also be used.

[0070] Examples of polybasic acids include one or more selected from succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydroisophthalic acid.

[0071] Examples of polyether-based diols used in the present invention include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols combining these.

[0072] The number-average molecular weight of the polymer diol is preferably in the range of 500 to 4000 when the molecular weight of the polyurethane elastomer is constant. By setting the number-average molecular weight to preferably 500 or more, and more preferably 1500 or more, it is possible to prevent the artificial leather from becoming hard. Furthermore, by setting the number-average molecular weight to 4000 or less, and more preferably 3000 or less, it is possible to maintain the strength of the polyurethane.

[0073] Examples of organic diisocyanates used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, as well as aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate. These can also be used in combination.

[0074] Preferably, amine-based chain extenders such as ethylenediamine and methylenebisaniline, and diol-based chain extenders such as ethylene glycol can be used. Alternatively, polyamines obtained by reacting polyisocyanate with water can also be used as chain extenders.

[0075] The polyurethane used in this invention may be combined with a crosslinking agent to improve water resistance, abrasion resistance, and hydrolysis resistance. The crosslinking agent may be an external crosslinking agent added to the polyurethane as a third component, or an internal crosslinking agent that introduces reaction sites to form a crosslinked structure into the polyurethane molecular structure beforehand can be used. From the viewpoint of forming crosslinked sites more uniformly within the polyurethane molecular structure and reducing the decrease in flexibility, it is preferable to use an internal crosslinking agent.

[0076] Compounds containing isocyanate groups, oxazoline groups, carbodiimide groups, epoxy groups, melamine resins, and silanol groups can be used as crosslinking agents.

[0077] Furthermore, polymeric elastic materials may contain various additives depending on the purpose, such as flame retardants (e.g., phosphorus-based, halogen-based, and inorganic types), antioxidants (e.g., phenol-based, sulfur-based, and phosphorus-based types), UV absorbers (e.g., benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based, and oxalic acid anilide-based types), light stabilizers (e.g., hindered amine-based and benzoate-based types), hydrolysis-resistant stabilizers (e.g., polycarbodiimide), plasticizers, antistatic agents, surfactants, coagulation modifiers, and dyes.

[0078] Generally, the content of the polymeric elastic material in artificial leather can be adjusted as appropriate, taking into account the type of polymeric elastic material used, the manufacturing method of the polymeric elastic material, and the texture and physical properties. However, in the present invention, it is preferable that the content of the polymeric elastic material be 10% by mass or more and 60% by mass or less relative to the mass of the fiber entanglement. By setting the content of the polymeric elastic material to 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, the bonding between fibers by the polymeric elastic material can be strengthened, and the abrasion resistance of the artificial leather can be improved. On the other hand, by setting the content of the polymeric elastic material to 60% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, the artificial leather can be made more flexible.

[0079] According to a preferred embodiment of the artificial leather of the present invention, the density of the fiber entanglement containing the polymer elastic body, i.e., the density of the fiber entanglement with the polymer elastic body (density of the woven fabric (b) and the artificial leather without flame retardant, as described later), is 0.20 g / cm³. 3 More than 0.50g / cm 3 Preferably, the density is 0.20 g / cm³. 3 Preferably 0.25 cm 3 By doing so, the artificial leather will have sufficient shape stability, dimensional stability, and strength. Furthermore, the artificial leather will become denser, resulting in a clean opening without fraying or other defects. On the other hand, the density will be 0.50 g / cm³. 3 The following is preferably 0.45 g / cm³ 3 The following measures improve the breathability and flexibility of the artificial leather.

[0080] [Functional agents (flame retardants, etc.)] The functional agents used in this invention refer to agents that impart functionality to textile products such as flame retardancy, stain resistance, yellowing resistance, NOx resistance, grip, water repellency, oil repellency, color transfer resistance, abrasion resistance, odor resistance, durability, flexibility, and stretchability. The functional agents (flame retardants, etc.) used in the artificial leather of this invention have a tackiness of 0.1 N / cm 2 More than 2.0N / cm 2 The following applies: The tackiness of the functional agent (flame retardant, etc.) is 0.10 N / cm². 2 Preferably 0.15 N / cm² 2 The above is more preferably 0.20 N / cm². 2 As a result of the above, when the functional agent (flame retardant, etc.) is applied and dried, the functional agent (flame retardant, etc.) adheres sufficiently to the fiber entanglement, and the functional agent (flame retardant, etc.) does not fall off even in high-temperature environments after drying. Tackiness: 2.00 N / cm 2 Preferably, 1.60 N / cm² 2 More preferably, 1.00 N / cm 2The following conditions ensure good opening formation, as fiber debris consisting of fibers, polymeric elastic material, and functional agent (flame retardant, etc.) does not clog the opening after it has been formed. Furthermore, if the opening is formed by punching, continuous processing is possible without fiber debris clogging the needle holes. In addition, the functional agent (flame retardant, etc.) is uniformly dispersed and bonded, resulting in a flexible texture for the artificial leather. In this invention, the tackiness of the functional agent (flame retardant, etc.) is defined as a value obtained by measuring and calculating as follows. (1) Heat the functional agent (flame retardant, etc.) to 60°C. (2) Using a tack meter, a stainless steel probe (contact pressure 24.5 N / cm) is applied to the functional agent (flame retardant, etc.). 2 Press the object at a speed of 6 mm / min and hold for 5 seconds. (3) After (2), read the maximum load when peeling at 6 mm / min. (4) Repeat steps (2) and (3) five times, and round the arithmetic mean of the obtained values ​​to the third decimal place.

[0081] Furthermore, in order to obtain the above-mentioned adhesion, openability, and softness stably even with temperature changes, the tackiness when the functional agent (flame retardant, etc.) is heated to 40°C should be 0.05 N / cm. 2 More than 1.00N / cm 2 The following is preferable, with a tackiness of 0.01 N / cm at 20°C. 2 More than 0.50N / cm 2 The following is preferable. In particular, for handling purposes such as molding and sewing of artificial leather sheets at room temperature, it is preferable that the tackiness at 20°C is low on the surface of the functional side (flame retardant side, etc.). By setting the tackiness of the functional agent within the above range, resistance is reduced when unrolling the artificial leather, improving the handling of the artificial leather in subsequent processes. The measurement of tackiness when the functional agent (flame retardant, etc.) is heated to 40°C or 20°C shall be performed using the same method as in (1) above, except that the heating temperature is changed to 40°C or 20°C.

[0082] The functional agent (flame retardant, etc.) may be the resin itself, which is a polymer compound having a functional functional group. However, it is preferable that it contains a resin in addition to a low molecular weight compound having a functional component (flame retardant component, etc.) in order to obtain durability of the functionality. The resin can be selected from, for example, acrylic resin, urethane resin, polyester resin, vinyl acetate resin, etc., and is not particularly limited, but it is preferable that it be an acrylic resin that has a good balance from the viewpoint of adhesion to fiber entanglement and woven / knitted fabrics, as well as heat resistance and adhesion. The amount of this binder resin is not limited to a specific value, but it is preferably used in the range of 5 to 50% by mass of the total mass of the functional component (flame retardant component, etc.) contained in the functional agent (flame retardant, etc.). If it is 5% by mass or less, the flame retardant is prone to shedding of powder components, and if it exceeds 50% by mass, the texture of the artificial leather may be impaired. From the viewpoint of tackiness, for example, a resin with low rubber elasticity is preferably used. For example, in the case of acrylic resins, acrylamide-based resins are preferable to acrylonitrile-based resins because they have better tackiness. Furthermore, resins generally tend to have a hard texture, but by reducing the amount of resin used, the texture can be softened. Using highly adhesive ethylene vinyl acetate resin results in high adhesion and tackiness even in small amounts, so it is preferable to include ethylene vinyl acetate when it is desirable to reduce the amount of resin used.

[0083] When the functional agent is a flame retardant and the combustion mode is carbonization, other resins that do not affect the formation of carbonized material, such as vinyl acetate or vinyl acetate copolymer resin, may be used as the resin of the flame retardant, for example, acrylic resin, SBR resin, or MBR resin. In particular, if the flame retardant further contains acrylic resin, the effects of softening the texture and improving the water resistance of the flame retardant to water can be obtained.

[0084] While there are no particular restrictions on the type of flame retardant component used in flame retardants, non-water-soluble or poorly water-soluble components are preferred from the viewpoint of "marking." Here, "marking" refers to the phenomenon in which, when moisture, such as water droplets, adheres to artificial leather treated with a flame retardant from either the front or back side, and then dries naturally, the wet area becomes covered with white spots or stains. From the viewpoint of complying with recent regulations on endocrine disruptors, it is preferable to use dehalogenated flame retardants. Examples of dehalogenated flame retardants include phosphorus-containing compounds, nitrogen-containing compounds, phosphorus nitrogen compounds, sulfoamide compounds, phosphorus sulfoamide compounds, and sulfur nitrogen compounds, and these can be used individually or in combination. From the viewpoint of flame retardancy, phosphorus compounds are preferred. Examples of phosphorus compounds include guanidine phosphate, carbamate phosphate, phosphate ester, phosphate ester amide, ammonium polyphosphate, and aromatic phosphate esters such as triphenyl phosphate and trixylenyl phosphate. In particular, ammonium polyphosphate flame retardants with a high phosphorus content are preferred, and those coated with melamine resin or silicon oxide resin are preferred to further reduce water solubility. Known inorganic flame retardants such as aluminum hydroxide, titanium dioxide, zinc oxide, expandable graphite, magnesium hydroxide, calcium carbonate, zinc borate, ammonium polyphosphate, and red phosphorus can be used, but it is preferable to use polyphosphate-based flame retardants which have excellent processability and durability.

[0085] The combustion modes of flame retardants include carbonization, which forms a carbonized film, and melting, which involves the falling of the ignition source. Neither mode is strictly limited to one, but in flame retardancy evaluation when sufficient flame retardancy is achieved, the melting mode is preferable from the viewpoint of flame retardancy stability.

[0086] In the artificial leather of the present invention, the flame retardancy shall be evaluated based on the combustion test standard (horizontal combustion rate) for automotive interior materials of the U.S. Federal Motor Vehicle Safety Standards (FMVSS), No. 302, by holding a test piece (350 mm x 100 mm) horizontally and applying a 38 mm flame for 15 seconds, and determining the flame retardancy based on the combustion rate over a distance of 254 mm between mark A and mark B, according to the following criteria. If the material extinguishes before reaching the A mark, the judgment category will be "non-combustible," and it will be considered a pass. If the device self-extinguishes beyond mark A, and the burning distance is within 50 mm and the burning time is within 60 seconds, the judgment category will be "self-extinguishment" and the device will be deemed to have passed. • If the firewood does not self-extinguish, but the burning rate between the markings is 4 inches / minute (approximately 101.6 mm / minute) or less, the judgment category will be "burning below the specified rate," and the firewood will be deemed to pass. If the firewood does not extinguish on its own and the burning rate between the markings exceeds 4 inches / minute (approximately 101.6 mm / minute), the judgment category will be "burning exceeding the specified rate," and the firewood will be deemed unacceptable.

[0087] Furthermore, if a carbonizing agent such as a stain repellent is applied to artificial leather, for example, using a carbonizing flame retardant increases the amount of carbonization, resulting in improved flame retardancy, and the combustion mode can be selected according to the material composition of the artificial leather. When a carbonizing flame retardant is selected, selecting a resin that easily carbonizes for the flame retardant resin reduces the aforementioned flame retardant components, which is preferable from a cost standpoint. For example, there are vinyl group-containing resins that form a carbonized skeleton during combustion.

[0088] The vinyl group-containing resin preferably includes at least one selected from vinyl acetate resin, ethylene vinyl acetate copolymer resin, acrylic vinyl acetate copolymer resin, vinyl vinyl acetate copolymer resin, and branched fatty acid vinyl vinyl acetate copolymer resin. This is preferable because the formation of carbides by using these vinyl acetate or vinyl acetate copolymer resins in combination with phosphorus compounds promotes flame retardancy, and is particularly effective in improving the flame retardancy properties of artificial leather against horizontal combustion.

[0089] The amount of flame retardant applied must be determined from the standpoint of ensuring the necessary flame retardancy while minimizing hardening of the texture. It will increase or decrease depending on the basis weight, thickness, ultrafine fibers, polymer type of the high-molecular-weight elastic material, and fiber entanglement type of the artificial leather, but it is preferable to contain 2 to 30% by mass relative to the artificial leather in order to achieve both flame retardancy and texture. The amount of flame retardant applied is 10 to 200 g / m². 2 Preferably, and more preferably, 20-100 g / m²2 It is best to keep it within the specified range. The amount of flame retardant applied can be calculated, for example, by subtracting the mass after application from the mass after application. However, if calculating from the artificial leather after application, it can also be calculated using elemental peak analysis such as X-ray fluorescence.

[0090] The solution used when applying the flame retardant to the artificial leather preferably has a viscosity of 500 to 10,000 mPa·s at room temperature from the viewpoint of coating penetration, and may contain a viscosity modifier as needed. The viscosity is more preferably 1,500 to 9,000 mPa·s, and even more preferably 2,500 to 7,000 mPa·s. By doing so, the abundance ratio of the flame retardant in the thickness direction, which will be described later, will be within a suitable range, and a more flexible and flame-retardant artificial leather can be obtained. The method for measuring the viscosity of the above solution is not particularly limited, but a commonly used rotational viscometer measurement method is used. The viscosity modifier used when adjusting the viscosity of the above solution is preferably poorly soluble in water from the viewpoint of preventing the occurrence of edge formation, and is preferably, for example, an alkali-thickening type acrylic resin or an ethylene oxide higher fatty acid ether.

[0091] In this invention, in addition to the above-mentioned components, the flame retardant further contains aluminum hydroxide as a flame retardant enhancer. Other materials such as nium, magnesium hydroxide, and metal oxides can also be used.

[0092] The amount of functional agent (flame retardant, etc.) to be applied must be determined from the viewpoint of ensuring the necessary functional performance, minimizing hardening of the texture, and the openability of the artificial leather base material. It will increase or decrease depending on the basis weight, thickness, ultrafine fibers, polymer type of high-molecular elastic material, and fiber entanglement type of the artificial leather, but it is preferable to contain 2 to 30% by mass relative to the artificial leather in order to satisfy the above characteristics. The amount of functional agent (flame retardant, etc.) to be applied is 10 to 200 g / m². 2 Preferably, and more preferably, 20-100 g / m² 2 It is best to keep it within the specified range.

[0101] [Artificial leather] The artificial leather of the present invention comprises the aforementioned fiber entanglement body and the aforementioned polymer elastic body, wherein one surface is a pile surface having a piled surface, and the other surface is a flame retardant surface having the aforementioned flame retardant.

[0102] First, in the artificial leather of the present invention, one surface is a napped surface. That is, the nap may be present only on the surface that becomes the product surface of the artificial leather, or it may be present on both sides. When the surface that becomes the product surface has a napped surface, from the viewpoint of design effect, it is preferable that the napped shape has a nap length and directional flexibility such that when the nap is traced with a finger, the direction of the nap changes and leaves a mark, a so-called finger mark. As an example of a form in which the other surface (back surface) of the artificial leather has a napped surface relative to the product surface, a flame retardant may be applied after forming a napped surface on the back surface of a fiber entanglement composite. Furthermore, when a woven or knitted fabric (b) is laminated on the back surface of a fiber entanglement composite, the front and back surfaces of the fiber entanglement composite are made napped, and a flame retardant is applied to the surface of the laminated woven or knitted fabric (b), thereby making the flame retardant present in the napped portion on the back surface of the fiber entanglement composite, and thus the flame retardant surface can have a napped surface.

[0103] More specifically, when the surface that will become the product surface is a pile surface, the pile length on that surface is preferably 50 μm or more and 500 μm or less, and more preferably 100 μm or more and 450 μm or less. By setting the pile length to 50 μm or more, the pile covers the polymer elastic material, suppressing the exposure of the polymer elastic material to the product surface of the artificial leather, thereby obtaining an elegant appearance. Furthermore, when a woven or knitted fabric (a) is intertwined and integrated with the fiber entanglement that constitutes the artificial leather, or when the fiber entanglement itself is made of a woven or knitted fabric, setting the pile length within the above range is preferable because it can sufficiently cover the structure of the woven or knitted fabric near the product surface of the artificial leather, thus obtaining a natural-like, elegant appearance. On the other hand, by setting the pile length to 500 μm or less, an artificial leather with excellent design effect and abrasion resistance can be obtained.

[0104] In this invention, the pile length of the artificial leather is calculated by the following method. (1) Using a lint brush or the like, raise the nap of the artificial leather and prepare a 1 mm thick section in the cross-sectional direction of a surface perpendicular to the longitudinal direction of the artificial leather. (2) Observe the cross-section of the artificial leather at 90x magnification using a scanning electron microscope (SEM). (3) In the captured SEM image, the height of the pile (layer consisting only of ultrafine fibers) is measured at 10 points at 200 μm intervals in the width direction of the cross-section of the artificial leather. (4) Calculate the average value (arithmetic mean) of the heights of the 10 measured pile sections (layers consisting only of ultrafine fibers).

[0105] In the artificial leather of the present invention, it is important that the functional surface (the surface containing the flame retardant, etc.) has multiple openings. In the present invention, "openings" are not limited to portions where holes (through-openings) penetrate the artificial leather from the pile surface to the functional surface (the surface containing the flame retardant, etc.), but also include cases where, for example, the woven fabric (b) and the openings do not overlap in the surface direction and therefore do not form through-openings. An example of the latter is a form in which openings are formed in advance in a woven fabric (b) containing a functional agent (flame retardant, etc.) and laminated onto a fiber entanglement assembly. The shape of these openings can be any shape according to the desired design, and can be round, elliptical, flat, triangular, or other polygonal shapes, fan-shaped, cross-shaped, hollow, Y-shaped, T-shaped, or U-shaped. The arrangement pattern of the openings is not particularly limited and may be arranged regularly or irregularly, but from the viewpoint of exhibiting uniform breathability and strength throughout the artificial leather, it is preferable that they be arranged regularly at predetermined intervals. From the viewpoint of achieving both breathability and strength for the entire artificial leather, the diameter of the openings is preferably 0.1 to 3.0 mm, and more preferably 0.5 to 2.5 mm.

[0106] Furthermore, in the artificial leather of the present invention, it is preferable that the opening ratio of the functional surface (flame retardant surface, etc.) be 1% or more and 40% or less, from the viewpoint of achieving both breathability and strength of the artificial leather as a whole. In other words, by setting it to 1% or more, more preferably 2% or more, an artificial leather with excellent breathability can be obtained. On the other hand, by setting it to 40% or less, more preferably 20% or less, and even more preferably 15% or less, an artificial leather with excellent strength can be obtained.

[0107] Furthermore, in the artificial leather of the present invention, it is preferable that the pile surface and the functional surface (flame retardant surface, etc.) each have a plurality of openings, and at least a portion of these openings are through-openings that penetrate from the pile surface to the functional surface (flame retardant surface, etc.). By doing so, an artificial leather with better breathability can be made.

[0108] The shape of the through-opening in the thickness direction can be, for example, cylindrical, where the hole diameters of the openings on the pile surface and the functional surface (flame retardant surface, etc.) are the same, or it can be a mortar-shaped through-opening where the hole diameters of the openings on the pile surface and the functional surface (flame retardant surface, etc.) are different. In other words, the shape of the through-opening can be selected considering the design and mechanical properties of the artificial leather.

[0109] In the artificial leather of the present invention, it is preferable that the ratio of the functional agent (flame retardant, etc.) in the thickness direction satisfies the following formula.

[0110] 0.001 ≤ W / W0 ≤ 0.7 Here, W is the thickness (mm) from the functional surface (the surface containing the flame retardant, etc.) where the functional agent (flame retardant, etc.) is present, and W0 is the total thickness (mm) of the artificial leather. By setting the thickness ratio of this functional agent (flame retardant, etc.) to 0.001 or more, more preferably 0.01 or more, and even more preferably 0.05 or more, an artificial leather with excellent functionality (flame retardancy, etc.) can be produced. On the other hand, by setting the thickness ratio of this functional agent (flame retardant, etc.) to 0.7 or less, more preferably 0.5 or less, and even more preferably 0.3 or less, an artificial leather with excellent breathability and flexibility can be produced.

[0111] The thickness-direction abundance ratio of the functional agent (flame retardant, etc.) is obtained by taking and preparing three SEM measurement samples, randomly selecting five locations in the observation image of each cross-section, measuring W and W0 at each location, and calculating W / W0 using the arithmetic mean. If the functional agent (flame retardant, etc.) cannot be identified from a normal SEM image, it is calculated using a method such as identifying resins containing elemental peaks as functional agents using SEM-EDX. For example, in the case of flame retardants, it is calculated using a method such as identifying resins containing phosphorus elemental peaks as flame retardants.

[0112] Furthermore, a preferred form of artificial leather from the viewpoint of functionality (flame retardancy, etc.) is one in which a woven or knitted fabric (b) is laminated onto a fiber entanglement body, and a functional agent (flame retardant, etc.) is unevenly distributed on the woven or knitted fabric (b).

[0113] A preferred form of the functional surface (flame retardant surface, etc.) of artificial leather is that the functional agent (flame retardant, etc.) is present on the surface of the functional surface (flame retardant surface, etc.), and the area ratio of the functional agent (flame retardant, etc.) on the functional surface (flame retardant surface, etc.) is preferably 10 to 100%. The above area ratio is obtained by taking and preparing three samples for SEM measurement, randomly selecting five locations in the 50x magnification observation image of the surface of each functional surface (flame retardant surface, etc.), taking SEM images, and after binarization processing, calculating the area ratio of the area where the functional agent (flame retardant, etc.) is present relative to the total area obtained by subtracting the aperture from the 50x magnification image area. By setting the area ratio to preferably 10% or more, and more preferably 30% or more, it is possible to produce artificial leather with excellent functionality (flame retardancy, etc.) and stability of functionality (flame retardancy, etc.). For example, when laminating polyurethane foam to the back surface of artificial leather such as vehicle interior material, the smoothness of the functional surface (flame retardant surface, etc.) is increased, which improves the peel strength with respect to the polyurethane foam.

[0114] The artificial leather of the present invention preferably has a thickness measured by "6.1.1 Method A" of "6.1 Thickness (ISO Method)" in JIS L1913:2010 "General Nonwoven Fabric Testing Methods" within the range of 0.2 mm to 2.5 mm. 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 a substantial feel and superior texture. On the other hand, by setting the thickness to 2.5 mm or less, more preferably 2.0 mm or less, and even more preferably 1.5 mm or less, it is possible to obtain a flexible artificial leather with excellent moldability.

[0115] The artificial leather of the present invention preferably has a friction fastness of grade 3 or higher, as measured by "9.1 Type I friction tester (clock meter) method" of JIS L0849:2013 "Test method for color fastness to friction" and a lightfastness of grade 3 or higher, as measured by "7.2 Exposure method a) First exposure method" of JIS L0843:2006 "Test method for color fastness to xenon arc light". Having a friction fastness and lightfastness of grade 3 or higher prevents color fading and staining of clothing, etc., during actual use.

[0116] In the abrasion resistance test of the present invention, measured by "8.19 Abrasion Resistance and Friction Discoloration Resistance" "8.19.5 Method E (Martindale Method)" of "Test Methods for Woven and Knitted Fabrics" in JIS L1096:2010, the mass loss of the artificial leather after 20,000 cycles of abrasion with a pressing load of 12.0 kPa is preferably 20 mg or less, more preferably 15 mg or less, and even more preferably 10 mg or less. A mass loss of 20 mg or less prevents shedding of fibers during actual use.

[0117] The artificial leather of the present invention preferably has a tensile strength of 20 to 400 N / cm in any measurement direction, as measured by "6.3.1 Tensile strength and elongation (ISO method)" of JIS L1913:2010 "General nonwoven fabric test methods". A tensile strength of 20 N / cm or more, more preferably 30 N / cm or more, and even more preferably 40 N / cm or more is preferable because it provides excellent morphological stability and durability for the artificial leather. Furthermore, a tensile strength of 400 N / cm or less, more preferably 300 N / cm or less, and even more preferably 250 N / cm or less results in an artificial leather with excellent moldability.

[0118] The artificial leather of the present invention preferably has a stiffness of 30 to 150 mm according to the cantilever method in JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics" "8.21 Stiffness and Softness", and is more preferably 50 to 130 mm, from the viewpoint of texture and flexibility.

[0119] The artificial leather of this invention achieves both flame retardancy and breathability in the breathability of 1 to 400 cm² according to Method A (Fragile type method) of "8.26 Breathability" of JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics". 3 / cm 2 It is preferably / sec, and more preferably 20-300 cm 3 / cm 2 / sec, more preferably 70-250cm 3 / cm 2 The value is / sec. Furthermore, in this invention, while breathability is greatly influenced by the openings, a breathable fiber entanglement is also preferable from the viewpoint of preventing stuffiness and promoting bacterial growth. Therefore, the breathability of a fiber entanglement without openings is 1 to 100 cm. 3 / cm 2 It is preferably / sec, more preferably 2 to 50cm 3 / cm 2 It is / sec.

[0120] The basis weight of the artificial leather of the present invention was measured in accordance with "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General nonwoven fabric testing methods," and was 50 g / m². 2 More than 800g / m2 The following range is preferable: The basis weight of the nonwoven fabric is 50 g / m². 2 Above, a comfortable 100g / m 2 More preferably 150 g / m² 2 By doing so, it is possible to produce a high-quality artificial leather with a substantial feel and excellent texture. On the other hand, 800g / m 2 More preferably 600g / m² 2 More preferably 500 g / m 2 By doing the following, it is possible to create a flexible artificial leather with excellent moldability.

[0121] For manufacturing the artificial leather having openings according to the present invention, the artificial leather base material preferably has a rigidity of 30 mm to 150 mm according to the cantilever method in "8.21 Rigidity" of JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics" from the viewpoint of the texture and flexibility of the artificial leather after opening formation, and more preferably 50 mm to 130 mm. Furthermore, by setting the rigidity to 30 mm to 150 mm, it becomes easier to form openings in the artificial leather base material. For example, when forming openings with a hollow punch such as a hole punch, the scraps of the artificial leather base material punched out at the opening can easily escape from the hollow part of the punch, resulting in good productivity in the opening formation process.

[0122] In the present invention, it is preferable that the dynamic friction coefficient of the functional surface of the artificial leather base material is 0.15 or more and 0.60 or less, in terms of ease of opening formation and productivity of the opening formation process. The friction coefficient affects the slipperiness between the functional material and the opening tool (punch, hollow needle, drill, etc.) when the opening method is perforation (punch, hollow needle, etc.) or drilling.

[0123] In the present invention, it is preferable that the amount of functional agent attached to the artificial leather base material is 2 to 30% by mass relative to the artificial leather base material, in terms of the above-mentioned characteristics of the artificial leather, the ease of forming the openings, and the productivity of the opening formation process. If the amount of functional agent attached is less than 2% by mass, the fiber scraps punched out at the openings of the artificial leather base material tend to unravel, and in the case of a punch, for example, they become difficult to remove from the hollow part. Also, if the amount of functional agent attached is greater than 30% by mass, the scraps tend to clog the hollow part, for example, in the case of a punch. The amount of attachment can be calculated from the weight change before and after application, similar to the amount of attachment, but it can also be calculated by chemical analysis such as fluorescent X-ray.

[0124] [Manufacturing method for artificial leather] The artificial leather of the present invention is a pile-like sheet made of a fiber entanglement body consisting of ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm and a polymer elastic material, with a tackiness of 0.1 N / cm² on one side. 2 More than 2.0N / cm 2 It is preferable that the product be manufactured by applying the following flame retardant to create a flame-retardant surface, and by ensuring that at least multiple openings are provided on the flame-retardant surface. The details of each step are described below.

[0125] <Process for manufacturing ultrafine fiber-generating fibers> The ultrafine fibers constituting the artificial leather of the present invention can be manufactured by conventionally known methods, such as the sea-island spinning method, the mixed spinning method, and the split-type composite spinning method used in synthetic fiber manufacturing. Using ultrafine fiber-generating fibers composed of two or more polymeric substances with different solubility in solvents is preferable in terms of productivity, such as the formation of fiber entanglements.

[0126] In the ultrafine fiber generation process, an island-type composite structure is produced in which island portions made of resin that will become ultrafine fibers are formed, and the easily soluble polymer forms the sea portion, thereby producing an ultrafine fiber generation type fiber.

[0127] As a type of fiber that generates ultrafine fibers, a sea-island type composite fiber is used, in which thermoplastic resins with different solvent solubility are used as a sea portion (easily soluble polymer) and an island portion (poorly soluble polymer), and the sea portion is dissolved and removed using a solvent or the like to make the island portion into ultrafine fibers. By using a sea-island type composite fiber, it is possible to provide appropriate voids between the island portions, i.e., between the ultrafine fibers inside the fiber bundle, when the sea portion is removed, which is preferable from the viewpoint of the texture and surface quality of artificial leather.

[0128] As a method for spinning ultrafine fibers having a sea-island type composite structure, a method using a polymer interconnected array that uses a sea-island type composite die and spins the sea portion and island portion in an interconnected manner is preferred from the viewpoint of obtaining ultrafine fibers with uniform single fiber fineness.

[0129] As for the method of incorporating pigment into the island portion, either a method can be employed in which the pigment is kneaded into the resin of the island portion and then spun using resin chips, or a method can be employed in which a masterbatch of resin kneaded with pigment is prepared in advance, and the masterbatch is mixed with another resin chip to spin the yarn.

[0130] For the "sea" portion of the sea-island type composite fiber, polyethylene, polypropylene, polystyrene, copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid or polyethylene glycol, and polylactic acid can be used. However, from the viewpoint of spinnability and ease of elution, polystyrene and copolymerized polyester are preferably used.

[0131] In the method for manufacturing artificial leather of the present invention, when using sea-island type composite fibers, it is preferable to use sea-island type composite fibers in which the strength of the island portion is 2.5 cN / dtex or more. By having an island portion strength of 2.5 cN / dtex or more, more preferably 2.8 cN / dtex or more, and even more preferably 3.0 cN / dtex or more, the abrasion resistance of the artificial leather can be improved and the decrease in friction fastness due to fiber shedding can be suppressed.

[0132] In the present invention, the strength of the island portion of the sea-island type composite fiber is calculated by the following method. (1) Bundle together 10 pieces of sea-island type composite fiber, each 20 cm long. (2) After dissolving and removing the sea tissue from the sample in (1), air dry it. (3) The test is performed 10 times (N=10) in accordance with "8.5 Tensile strength and elongation" of "8.5 Standard time test" in JIS L1013:2010 "Test method for chemical fiber filament yarn", under the conditions of grip length 5 cm, tensile speed 5 cm / min, and load 2 N. (4) The arithmetic mean (cN / dtex) of the test results obtained in (3) is rounded to two decimal places and the resulting value is taken as the strength of the island portion of the sea-island type composite fiber.

[0133] <Process for manufacturing fiber entanglements> Conventional methods for manufacturing entangled fiber fabrics, such as woven or nonwoven fabrics, using ultrafine fibers or sea-island composite fibers, can be applied. Preferably, the spun ultrafine fiber-generating fibers are opened and then formed into a fiber web using a cross wrapper or the like, and then entangled to obtain a nonwoven fabric. As a method for entangling the fiber web to obtain a nonwoven fabric, needle punching or water jet punching can be used.

[0134] As mentioned above, both short-fiber and long-fiber nonwoven fabrics can be used as the form of the nonwoven fabric. However, with short-fiber nonwoven fabrics, there are more fibers oriented in the thickness direction of the artificial leather compared to long-fiber nonwoven fabrics, resulting in a denser surface texture when the artificial leather is napped.

[0135] When producing a short-fiber nonwoven fabric, the obtained ultrafine fiber-generating fibers are preferably crimped and cut to a predetermined length to obtain raw fibers, which are then opened, laminated, and interwoven to obtain the short-fiber nonwoven fabric. Known methods can be used for the crimping and cutting processes.

[0136] Furthermore, if the artificial leather includes a woven or knitted fabric (a), the resulting nonwoven fabric and the woven or knitted fabric (a) are laminated and then intertwined and integrated. To intertwine and integrate the nonwoven fabric and the woven or knitted fabric (a), the woven or knitted fabric (a) can be laminated to one or both sides of the nonwoven fabric, or the woven or knitted fabric (a) can be sandwiched between multiple nonwoven fabric webs, and then the fibers of the nonwoven fabric and the woven or knitted fabric (a) can be intertwined by processes such as needle punching or water jet punching.

[0137] The apparent density of a nonwoven fabric made of ultrafine fiber-generating fibers after needle punching or water jet punching is 0.15 g / cm³. 3 More than 0.45g / cm 3 Preferably, the apparent density is 0.15 g / cm³. 3 By doing so, the sheet material can be obtained with sufficient morphological and dimensional stability. On the other hand, the apparent density is preferably 0.45 g / cm³. 3 By doing the following, it is possible to maintain sufficient space for imparting a polymeric elastic material.

[0138] In addition, it is preferable to subject the aforementioned nonwoven fabric to heat shrinkage treatment using hot water or steam in order to improve the density of the fibers.

[0139] Next, the nonwoven fabric can be impregnated with an aqueous solution of a water-soluble resin and dried to impregnate it with the water-soluble resin. By impregnating the nonwoven fabric with the water-soluble resin, the fibers are fixed and dimensional stability is improved.

[0140] <Process for generating ultrafine fibers> When using sea-island type composite fibers, this process involves treating the resulting fibrous substrate with a solvent to produce ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm.

[0141] The ultrafine fiber formation process can be carried out by immersing a nonwoven fabric made of sea-island type composite fibers in a solvent and dissolving and removing the sea portion of the sea-island type composite fibers.

[0142] When the ultrafine fiber-generating fiber is a sea-island type composite fiber, the solvent used to dissolve and remove the sea portion can be an organic solvent such as toluene or trichloroethylene if the sea portion is polyethylene, polypropylene, or polystyrene. If the sea portion is copolymerized polyester or polylactic acid, an alkaline aqueous solution such as sodium hydroxide can be used. If the sea portion is a water-soluble thermoplastic polyvinyl alcohol-based resin, hot water can be used.

[0143] <Process for imparting polymeric elasticity> In this process, a polymer elastomer solution is impregnated into a fiber entanglement mainly composed of ultrafine fibers or ultrafine fiber-generating fibers, and then solidified to impregnate it with a polymer elastomer. Methods for fixing the polymer elastomer to the fiber entanglement include wet solidification or dry solidification after impregnation with the polymer elastomer solution, and these methods can be appropriately selected depending on the type of polymer elastomer used.

[0144] When imparting polyurethane as a polymeric elastic material, N,N'-dimethylformamide and dimethyl sulfoxide are preferred solvents. Alternatively, a water-dispersible polyurethane solution, in which polyurethane is dispersed as an emulsion in water, may be used.

[0145] Furthermore, the addition of the polymeric elastic material to the fiber entanglement may be done before generating ultrafine fibers from the ultrafine fiber generating type fiber, or it may be done after generating ultrafine fibers from the ultrafine fiber generating type fiber.

[0146] <Process of cutting and polishing a fiber entanglement containing a polymeric elastic material> After completing the above process, the fiber entanglement body to which the polymer elastic material has been added is also preferably cut in half in the thickness direction to form two half-sheets of fiber entanglement body, from the viewpoint of manufacturing efficiency.

[0147] Furthermore, a napped surface can be formed on a fiber entanglement composite or a halved sheet-like material to which the aforementioned polymeric elastic material has been applied. The napped surface can be applied by grinding using sandpaper or a roll sander. The napped surface can be applied to one side only or to both sides.

[0148] When applying a napping treatment, a lubricant such as a silicone emulsion can be applied to the surface of the fiber entanglement before the napping treatment. In addition, applying an antistatic agent before the napping treatment makes it less likely for grinding dust generated by grinding to accumulate on the sandpaper. In this way, a napped sheet-like material with a raised nap surface is formed.

[0149] <Process for dyeing a pile-like sheet material> It is preferable to subject the above-mentioned pile-like sheet material to a dyeing treatment. This dyeing treatment can include, for example, immersion dyeing using a jigger dyeing machine or a liquid flow dyeing machine, thermosol dyeing using a continuous dyeing machine, or printing on the pile surface using roller printing, screen printing, inkjet printing, sublimation printing, and vacuum sublimation printing. Among these, using a liquid flow dyeing machine is preferable from a quality and grade standpoint because it provides a flexible texture. Furthermore, various resin finishing processes can be applied after dyeing as needed.

[0150] <Process for laminating and integrating woven or knitted fabrics (b)> It is preferable to laminate (b) the woven or knitted fabric with adhesive onto the side opposite to the piled surface of the piled sheet (or the piled surface on the product side if both sides have piled surfaces). The adhesive can be applied in a predetermined amount using devices such as rotary screens, knife roll coaters, gravure roll coaters, kiss roll coaters, and calender coaters. Among these, it is preferable to form a discontinuous adhesive layer using a rotary screen or gravure roll coater because it provides a good texture as artificial leather. Forming a discontinuous adhesive layer prevents hardening of the texture and reduction of breathability of the artificial leather. The above-mentioned discontinuous adhesive layer refers to a mixture of areas where adhesive is present and areas where it is not present on the horizontal surface of the woven or knitted fabric or piled sheet that is the adhesive surface, for example, by arranging the adhesive in a dot pattern.

[0151] When a thermoplastic resin is used as the adhesive, the materials can be bonded together by heat compression. Heat compression can be performed using methods such as a heat roll. When using a heat roll, it is preferable to set the temperature of the heat roll on the woven or knitted fabric side higher than the temperature of the heat roll on the surface sheet side. When a wet-curing resin is used as the adhesive, bonding is promoted under appropriate temperature and humidity conditions known as curing.

[0152] When heat-pressing with a heat roll, the roll temperature on the woven or knitted fabric side is preferably 80 to 180°C, and more preferably 100 to 160°C. If the roll temperature on the woven or knitted fabric side is lower than 80°C, bonding will take longer and the process load will increase. Also, if the roll temperature on the woven or knitted fabric side is higher than 180°C, the texture of the artificial leather will become rough and hard.

[0153] <Process of adding functional agents (flame retardants, etc.)> A functional agent (such as a flame retardant) is applied to one surface of the aforementioned pile-like sheet material to create a functional surface (the surface with the flame retardant, etc.), thereby obtaining an artificial leather base material. Here, the tackiness is 0.1 N / cm. 2 More than 2.0N / cm 2The following functional agents (flame retardants, etc.) are applied to create a functional surface (flame retardant surface). Alternatively, the dynamic friction coefficient (JIS K 7125) of the functional surface is 0.15 or more and 0.60 or less, and the rigidity of the artificial leather base material is 30 mm or more and 150 mm or less. This process forms the functional surface (flame retardant surface, etc.) on the surface opposite to the pile surface of the pile-like sheet material (if both sides have pile surfaces, the pile surface on the side that will become the product surface).

[0154] One method for forming a functional surface (such as a flame-retardant surface) is to apply it to a laminated sheet formed by laminating the aforementioned pile-like sheet material or woven / knitted fabric (b) using equipment such as a rotary screen, knife roll coater, gravure roll coater, kiss roll coater, and calender coater. It may also be applied by padding and then migrated to the surface during drying, but the stability of the uneven distribution to the surface is inferior. The aforementioned napping treatment may be further applied after drying with the functional agent (flame retardant, etc.). Alternatively, the functional agent (flame retardant, etc.) may be applied to the woven / knitted fabric (b) in advance, and then the woven / knitted fabric (b) may be laminated to the surface opposite to the pile-like surface of the pile-like sheet material (if both sides have pile-like surfaces, the pile-like surface on the side that will become the product surface) to form the functional surface (flame retardant surface, etc.).

[0155] After the functional agent (flame retardant, etc.) is applied, it penetrates into the material. Therefore, the amount applied and the amount of penetration are adjusted by considering factors such as the viscosity of the functional agent (flame retardant, etc.) and the mesh size of the gravure roll, for example. As for drying after applying the functional agent (flame retardant, etc.), drying can be done using a known dryer such as a tenter dryer.

[0156] <Process for forming an opening> Then, the functional (flame retardant, etc.) sheet having the aforementioned functional surface (flame retardant, etc.) is given multiple openings, at least on the functional surface (flame retardant, etc.). Means for creating the openings include perforation, drilling, laser processing, etc. Openings may be formed not only on the functional surface (flame retardant, etc.) but also on the other surface. There is no limit to the timing of opening; for example, the fiber entanglement composite and the woven / knitted fabric (b) may be opened separately and then laminated together. Preferably, the functional agent (flame retardant, etc.) is applied to the laminated sheet, and through-openings are formed using a drill, perforation needle, or hole punch. Artificial leather is obtained by forming these openings.

[0157] After openings are formed in the artificial leather, the contact area becomes smaller than before the openings were formed, resulting in a decrease in the coefficient of dynamic friction of the functional surface. For example, when polyurethane foam is laminated to the functional surface using frame lamination, or from the viewpoint of handling in the next process, a coefficient of dynamic friction of 0.10 to 0.55 is preferable for artificial leather with openings.

[0158] <Post-processing process> Furthermore, artificial leather can be treated with decorative elements on its surface as needed. For example, post-processing treatments such as embossing, laser processing, pin sonic processing, and printing can be applied.

[0159] The artificial leather of the present invention, obtained by the manufacturing method exemplified above, has moderate breathability and a flexible texture, while possessing excellent functionality (flame retardancy, etc.), a touch and elegant appearance similar to natural suede, and can be used in a wide range of applications from vehicle interior materials, interior materials, building materials, and general merchandise. However, due to its excellent functionality (flame retardancy, etc.), it is particularly suitable for use in vehicle interior materials. Furthermore, the artificial leather base material of the present invention, obtained by the manufacturing method exemplified above, has excellent opening-forming properties and is suitable for use in the manufacture of the above-mentioned artificial leather. [Examples]

[0160] Next, the artificial leather of the present invention will be described in more detail using examples, but the present invention is not limited to these examples. Unless otherwise specified, the measurements of each physical property were performed based on the methods described above.

[0161] [Measurement method and evaluation processing method] (1) Average single fiber diameter of ultrafine fibers (μm) For measuring the average single fiber diameter of ultrafine fibers, observation was performed using a Keyence VW-9000 scanning electron microscope, and the average single fiber diameter was calculated.

[0162] (2) Abrasion resistance of artificial leather In the abrasion resistance test measured according to "8.19 Abrasion Resistance and Friction Discoloration Resistance" of "8.19.5 Method E (Martindale Method)" in JIS L1096:2010 "Test Methods for Woven and Knitted Fabrics," a pressing load of 12.0 kPa was applied, and after 20,000 cycles of abrasion, the abrasion state of the artificial leather surface was observed and compared with the surface condition before the test. The degree of abnormality was then graded according to the following criteria. In this evaluation, grades 3 to 5 were considered passing. Grade 5: Not recognized at all. • Grade 4: Slightly noticeable, but hardly noticeable. Grade 3: Clearly noticeable, but not conspicuous. • Grade 2: Somewhat significant abnormalities are observed. • Grade 1: There is a significant abnormality.

[0163] (3) Tensile strength of artificial leather Two 2cm x 20cm test pieces were taken from the artificial leather in any direction, and the tensile strength was measured according to JIS L1913:2010 "General Nonwoven Fabric Testing Methods" "6.3.1 Tensile Strength and Elongation (ISO Method)". The average of the two measured pieces was used as the tensile strength of the artificial leather.

[0164] (4) Appearance quality and touch of artificial leather The appearance quality and touch of the artificial leather were evaluated by 20 evaluators (10 healthy adult men and 10 healthy adult women) who visually judged the following criteria. The evaluation with the highest number of votes was designated as the quality and touch of the artificial leather. In the case of a tie in the number of votes, the higher-rated artificial leather was designated as the quality and touch of that artificial leather. The passing levels for this invention were "A, B, C". A: It has an elegant appearance and a fine surface touch like genuine leather, giving it the highest level of luxury. B: While inferior to genuine leather, it has a somewhat elegant appearance and a slightly finer surface texture, giving it a mid-range level of luxury. ·C: It has an artificial-like elegance and surface touch, possessing a low-end sense of luxury. • D: It lacks elegance and has a rough surface texture, giving it the feel of a low-priced product.

[0165] (5) Evaluation of breathability of artificial leather For the artificial leather to be measured, one 200mm x 200mm test piece was taken from each of five different locations, and measured using Method A (Fragile method) of "8.26 Air permeability" in JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics". The amount of air passing through the test piece (cm³) was determined using the conversion table provided with the tester. 3 / cm 2 The breathability (cm² / sec) was calculated. Furthermore, the average of the five values ​​obtained was used to determine the breathability (cm²). 3 / cm 2 ( / sec)

[0166] (6) Flexibility test of artificial leather The flexibility of the artificial leather was evaluated based on the cantilever method described in "8.21 Rigidity and Softness" of JIS L1096:2010 "Test Methods for Woven and Knitted Fabrics". A 2cm x 15cm test specimen was prepared, placed on a horizontal table with a 45° inclination, and the specimen was slid along the cantilever. The scale was read when the center point of one end of the specimen touched the inclination.

[0167] (7) Flame retardancy test of artificial leather As described above, the evaluation was conducted based on the U.S. Federal Motor Vehicle Safety Standard (FMVSS), No. 302, the combustion test standard (horizontal combustion rate) for automotive interior materials. The size of the test specimen at that time was 350 mm x 100 mm.

[0168] (8) Edge adhesion test of artificial leather Place the artificial leather sample on top and add 3 cm of water to the surface. 3 After applying the solution and allowing it to air dry, the appearance of ring stains or other marks on the sample surface was observed. Samples with clearly visible ring stains or other marks were deemed unacceptable.

[0169] (9) Opening ratio of artificial leather The opening ratio refers to the percentage of the total area occupied by openings on one side of the artificial leather, and specifically refers to the area ratio on the aforementioned side. A 20cm x 20cm sample of artificial leather was scanned by image capture, and the area ratio was calculated by binarization processing. This process was performed on five samples, and the area ratio was determined by the arithmetic mean.

[0170] (10) Ratio of flame retardant in the thickness direction The ratio of flame retardant in the thickness direction was calculated by observing the cross-section of the artificial leather using a Keyence VW-9000 scanning electron microscope (SEM) and employing the method described above.

[0171] (11) Density of fiber entanglement containing polymeric elastic material The density of the fiber entanglements containing polymeric elastics shown in the examples and comparative examples (density of woven fabric (b) and artificial leather without flame retardants) was calculated by measuring the basis weight of the fiber entanglement with polymeric elastics (including woven fabric (a) if present) according to JIS L1913:2010 "General Nonwoven Fabric Testing Methods" "6.2 Mass per Unit Area (ISO Method)" as described above, and dividing it by the thickness of the fiber entanglement with polymeric elastics. Five samples were randomly selected from the fiber entanglement samples containing polymeric elastics, and the average value was used as the density.

[0172] Density (g / cm 3 ) = weight (g / m 2() ÷ thickness (mm) ÷ 1000).

[0173] (12) Tackiness of functional agents The measurements and calculations were performed using the following procedure. (1) The functional agent was heated to 60°C. (2) Using a tack meter (Tack Taster TA-500, manufactured by UBM Co., Ltd.), a stainless steel probe (contact pressure 24.5 N / cm) is applied to the functional agent (flame retardant, etc.) 2 The object was pressed down at a speed of 6 mm / min and held for 5 seconds. (3) After (2), the maximum load when peeling at 6 mm / min was read. (4) Repeat steps (2) and (3) five times, and round the arithmetic mean of the obtained values ​​to the third decimal place. This value was defined as the tackiness at 60°C.

[0174] (13) Coefficient of kinetic friction Three 80mm x 200mm test pieces were taken from the artificial leather, and the functional surface was measured according to JIS K 7125 at a test speed of 100mm / min, with a sliding piece of 63mm x 63mm and a load of 1.92N. The average value was used as the coefficient of dynamic friction.

[0175] [Example 1] <Raw Cotton Manufacturing Process> Using polyethylene terephthalate as the island component and polystyrene as the sea component, and using a sea-island type composite die with 16 islands, melt-spinning was performed with an island / sea mass ratio of 80 / 20, a discharge rate of 1.2 g / (min·hole), and a spinning speed of 1100 m / min. The resulting material was then stretched 2.7 times in a spinning oil solution bath at 90°C. After crimping using a push-type crimping machine, the material was cut to a length of 51 mm to obtain raw cotton of a sea-island type composite fiber with a single fiber fineness of 3.8 dtex.

[0176] <Process for manufacturing fiber entanglements> First, using the raw cotton obtained as described above, a laminated web was formed through carding and cross-wrapping processes. Then, at 2500 strands / cm 2 The needle-punched material has a weight of 540g / m².2 Then, we obtained a nonwoven fabric with a thickness of 2.4 mm.

[0177] <Process for generating ultrafine fibers> The nonwoven fabric obtained as described above was subjected to shrinkage treatment with hot water at 96°C. Then, an aqueous solution of polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) with a concentration of 12% by mass and a saponification degree of 88% was impregnated into the nonwoven fabric that had been shrunk with hot water. Furthermore, this was squeezed with a roll and dried for 10 minutes with hot air at 120°C while migrating the PVA, to obtain a PVA-coated sheet in which the mass of PVA relative to the mass of the sheet substrate was 25% by mass. The PVA-coated sheet thus obtained was immersed in trichloroethylene and subjected to mangle extraction and compression 10 times. This dissolved and removed the PVA and compressed the PVA-coated sheet, obtaining a PVA-coated sheet in which bundles of ultrafine fibers coated with PVA were intertwined. The average single fiber diameter of the ultrafine fibers was 4.4 μm.

[0178] <Process for imparting polymeric elasticity> The PVA-coated sheet obtained as described above was immersed in a polyurethane dimethylformamide (DMF) solution, which was prepared to have a solid content concentration of 13% with polyurethane as the main component. The desaturated PVA-coated sheet immersed in the polyurethane DMF solution was then squeezed with a roller. Next, this sheet was immersed in a 30% by mass DMF aqueous solution to solidify the polyurethane. Afterward, the PVA and DMF were removed with hot water, and a silicone oil emulsion solution adjusted to a concentration of 1% by mass was impregnated. The amount of silicone lubricant applied was 0.5% by mass relative to the total mass of the fiber entanglement and the polyurethane, and the sheet was dried with hot air at 110°C for 10 minutes. This resulted in a polyurethane-coated sheet with a thickness of 1.8 mm and a polyurethane mass of 33% by mass relative to the mass of the fiber entanglement. The density of the polyurethane-coated sheet, which is a fiber entanglement containing a polymeric elastic material, was 0.35 g / cm³. 3 That was the case.

[0179] <Half-cutting and napping process> The polyurethane-coated sheets obtained as described above were cut in half so that each half had half the thickness. Next, the surface layer of the cut surfaces was sanded to a thickness of 0.3 mm using 180-grit endless sandpaper to create a napped surface, resulting in a 0.6 mm thick napped sheet.

[0180] <Dyeing and finishing processes> The pile sheet obtained as described above was dyed with a black disperse dye using a jet dyeing machine at 120°C and then reduced and washed. After that, it was dried at 100°C for 7 minutes, resulting in an average single fiber diameter of 4.4 μm and a basis weight of 220 g / m². 2 A stained sheet with a thickness of 0.70 mm was obtained.

[0181] <Flame-retardant processing> Flame retardant A was obtained by mixing 20 parts by mass of silicon dioxide resin-treated ammonium polyphosphate (manufactured by Wellchem, phosphorus content 28%, nitrogen content 14%) as the main flame retardant component, 0.2 parts by mass of polyoxyethylene sorbitan monostearate (nonionic surfactant) as a surfactant, 11 parts of methyl acrylate resin with 50% nonvolatile content and 4 parts by mass of melamine cyanurate (nitrogen content 49.4%) as a binder resin, and hydroxyethyl cellulose as a thickener. A flame retardant solution containing 70% by mass of flame retardant A (the viscosity of which was adjusted to 3000 mPa·s with the aforementioned thickener) was applied to one surface of the dyed sheet opposite to the product surface using a screen coater, and then dried at a temperature of 100°C for 7 minutes to obtain a flame retardant-coated sheet in which the amount of flame retardant adhering to the mass of the artificial leather after drying was 20% by mass.

[0182] <Punching process> The above-mentioned flame-retardant-coated sheet was perforated using a perforated board with needles to create holes, thereby obtaining artificial leather (needle diameter: 1.2 mm, vertical pitch: 5 mm, horizontal pitch: 5 mm, opening ratio: 6%). After perforation, the perforated holes were free from fiber debris clogging, and no flame retardant adhered to the edges of the holes, forming clean openings. No fiber debris or flame retardant adhered to the perforated board after processing, even after blowing away debris with air. The resulting artificial leather possessed moderate breathability and a flexible texture, while also exhibiting excellent flame retardancy, a dense touch similar to natural suede, and an elegant appearance. The tackiness of the flame retardant was 0.45 N / cm at 60°C. 2 0.20 N / cm² at 40°C 2 0.14 N / cm² at 20℃ 2 The weight of the artificial leather was 240g / m². 2 The thickness was 0.72 mm. The results are shown in Table 1.

[0183] [Example 2] An ultrafine fiber-generating fiber having a sea-island type composite structure consisting of island and sea components was melt-spun using a sea-island type composite die with 16 islands, with an island / sea mass ratio of 55 / 45, a discharge rate of 1.0 g / (min·hole), and a spinning speed of 1100 m / min. Artificial leather was then obtained in the same manner as in Example 1, except that the stretching ratio in a spinning oil solution bath at 90°C was 3.4 times. The density of the polyurethane-coated sheet was 0.360 g / cm³ 3 The result was higher than in Example 1, with less penetration of the flame retardant, resulting in a W / W0 of 0.07. The average single fiber diameter of the ultrafine fibers was 2.9 μm. The results are shown in Table 1.

[0184] [Example 3] Using the raw cotton described in Example 1, a laminated web was formed through carding and cross-wrapping processes. Then, a twisted yarn made from polyethylene terephthalate multifilaments with an intrinsic viscosity (IV value) of 0.65 (average single fiber diameter: 11 μm, total fineness: 84 dtex, 72 filaments) twisted at 2500 T / m was used for both the warp and weft threads, resulting in a plain weave fabric with a weave density of 95 threads / 2.54 cm in the warp and 76 threads / 2.54 cm in the weft (weight 75 g / m²). 2were laminated above and below the laminated web. Then, needle punching was performed at a punching density of 2500 punches / cm 2 to obtain a non-woven fabric of fiber complex with a basis weight of 700 g / m 2 and a thickness of 3.0 mm, except that the average single fiber diameter of the ultrafine fibers was 4.4 μm, the basis weight was 360 g / m 2 , and an artificial leather with a thickness of 1.0 mm was obtained. A tough artificial leather with higher strength than that of Example 1 was obtained. The results are shown in Table 1.

[0185] [Example 4] A multifilament made of polyethylene terephthalate (total fineness: 48 dtex, 18 filaments) was used to create a tricot fabric using a single tricot machine, and dyed with a black disperse dye to prepare a dyed tricot fabric with a density of 32 warp threads / 2.54 cm and 48 weft threads / 2.54 cm. As an adhesive, a low-melting-point nylon resin (softening temperature 90 °C) was applied in dots at 20 g / m 2 using a gravure roll coater, and then dried with hot air at a temperature of 100 °C to obtain an adhesive-coated tricot. By thermocompression bonding the tricot side to the dyed sheet of Example 3 using a heat roll heated to a temperature of 150 °C, a composite sheet with a basis weight of 440 g / m 2 and a thickness of 1.1 mm was obtained. The composite sheet was subjected to flame retardant treatment and punching in the same manner as in Example 3 to obtain an artificial leather with a basis weight of 490 g / m 2 and a thickness of 1.2 mm. An artificial leather with even higher strength than that of Example 3 was obtained. Since the flame retardant adhered to the entire tricot and the single-component tricot became highly flame retardant, the artificial leather had high flame retardancy. The results are shown in Table 1.

[0186] [Example 5] A circular knit base fabric was knitted in a blister structure using interlaced yarn containing a multifilament (84 dtex / 25 f, average single fiber diameter of ultrafine fibers after desalination: 9 μm) made from a sea-island composite yarn with polyethylene terephthalate as the island component and polystyrene as the sea component, and a multifilament (33 dtex / 12 f) of polyethylene terephthalate. An artificial leather consisting of a fiber entanglement containing a polymeric elastic material was obtained in the same manner as in Example 1, except that the fiber entanglement was used as the circular knit base fabric. The basis weight of the artificial leather was 240 g / m². 2 The thickness was 0.72 mm. Compared to Example 1, it had a lower-grade feel and a relatively hard texture, but an artificial leather with excellent edge grip and punching properties was obtained. The results are shown in Table 1.

[0187] [Example 6] Regarding the flame retardant, flame retardant B was obtained by using 30 parts by mass of a dialkylphosphinate metal salt as the main component of the flame retardant and 15 parts by mass of an acrylic ester copolymer as the binder resin. Except for preparing a flame retardant processing agent solution containing 50% by mass of flame retardant B, the procedure was the same as in Example 4, resulting in a basis weight of 490 g / m². 2 A synthetic leather with a thickness of 1.2 mm was obtained. The tackiness of the flame retardant was 1.50 N / cm at 60°C. 2 0.50 N / cm² at 40°C 2 0.30 N / cm² at 20°C 2 As a result, the flame retardant exhibited high tack at room temperature, less penetration than in Example 4, and high tackiness at 60°C. Although some clogging occurred in the holes and on the punching board needles after punching, an artificial leather with excellent flame retardancy and appearance quality was obtained. The results are shown in Table 1.

[0188] [Example 7] Artificial leather was obtained in the same manner as in Example 4, except that the opening ratio was set to 14%. Compared to Example 4, the flame retardancy was slightly inferior due to the larger number of openings, but an artificial leather with excellent flexibility and other properties was obtained. The results are shown in Table 1.

[0189] [Comparative Example 1] Regarding the flame retardant, artificial leather was obtained in the same manner as in Example 4, except that 5 parts by mass of methyl acrylate resin and 10 parts by mass of acrylonitrile resin were used as the binder components. The result was high tackiness, clogging of the openings during punching, and poor breathability. The results are shown in Table 1.

[0190] [Comparative Example 2] Artificial leather was obtained in the same manner as in Example 4, except that the average single fiber diameter of the ultrafine fibers was set to 11 μm. The result was a rough surface texture lacking elegance. The results are shown in Table 1.

[0191] [Table 1]

[0192] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the intent and scope of the invention.

Claims

1. Artificial leather comprising a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastic body, wherein one surface is a pile surface having a raised nap, and the other surface is a flame retardant surface having a flame retardant, and satisfying all of the following requirements 1 to 4. Requirement 1: The flame-retardant surface has at least a plurality of openings. Requirement 2: The tackiness of the flame retardant is 0.1 N / cm. ２ 2.0N / cm or more ２ The following applies: Requirement 3: The opening ratio of the flame-retardant surface is 1% or more and 40% or less. Requirement 4: The ratio of the flame retardant in the thickness direction satisfies the following equation. 0.05≦W / W 0≦0.5 Here, W is the thickness (mm) from the flame-retardant surface where the flame retardant is present, and W0 is the total thickness (mm) of the artificial leather.

2. The artificial leather according to claim 1, wherein the artificial leather has a plurality of openings in the pile surface and the flame-retardant surface, and at least a portion of the openings are through-openings that penetrate from the pile surface to the flame-retardant surface.

3. The artificial leather according to claim 1 or 2, wherein the fiber entanglement body is formed by integrating the fiber entanglement body containing the ultrafine fibers with a woven or knitted fabric (a).

4. The artificial leather according to any one of claims 1 to 3, wherein the flame retardant comprises a phosphorus-based compound.

5. The density of the fiber entanglement containing the aforementioned polymeric elastic material is 0.20 g / cm³. ３ 0.50g / cm or more ３ The artificial leather according to any one of claims 1 to 4, which is as follows:

6. A method for producing artificial leather according to any one of claims 1 to 5, comprising applying a flame retardant having a tackiness of 0.1 N / cm² to 2.0 N / cm² to one surface of a pile-like sheet made of a fiber entanglement body containing ultrafine fibers with an average single fiber diameter of 0.1 μm to 10 μm and a polymer elastic body, thereby forming a flame-retardant surface, and ensuring that at least a plurality of openings are provided on the flame-retardant surface.

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