Artificial leather, its manufacturing method and artificial leather substrate

Abstract

The objective of this invention is to provide an artificial leather with moderate breathability and a soft feel, excellent flame retardancy, and a texture and elegant appearance similar to natural suede. This artificial leather comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer; one surface having a napped surface, and the other surface having a flame-retardant surface; and satisfying the following requirements 1 and 2: Requirement 1: At least a plurality of openings are provided on the flame-retardant surface. Requirement 2: The viscosity of the flame retardant is 0.1 N / cm² or more and 2.0 N / cm² or less.

Description

[Technical Field]

[0001] This invention relates to an artificial leather composed of a fiber complex containing extremely fine fibers, a polymer elastomer, and a functional agent (flame retardant, etc.), possessing moderate breathability and a soft feel, excellent flame retardancy, and a touch and elegant appearance similar to natural suede. Furthermore, this invention relates to an artificial leather substrate with good opening-forming properties for obtaining this artificial leather. [Previous Technology]

[0002] It is known that artificial leather, which is composed of fiber complexes containing extremely fine fibers and polymer elastomers, has a napped texture. Compared with natural leather, it has superior characteristics such as higher breathability or durability and uniform quality. It is not only used as a material for clothing, but also as interior material for public transportation aircraft such as airplanes, ships, and railway vehicles, as well as interior material for vehicles, decoration materials, building materials, and general merchandise.

[0003] In the aforementioned fields, there is a frequent requirement for artificial leather to have high flame-retardant properties. In areas where flame retardancy is required, artificial leather is generally infused with flame retardants. In particular, in vehicle interior materials, adequate ventilation is needed to accommodate ventilation systems, due to the density or material composition of the artificial leather and the control of openings.

[0004] However, in order to make artificial leather flame-retardant, methods such as applying flame retardant to the very fine fibers, applying flame retardant to the entire artificial leather, or applying flame retardant to one side of the artificial leather are used.

[0005] However, it is known that artificial leather obtained by such methods is extremely difficult to make flame-retardant because the polymer elastomers such as polyurethane that constitute it and the extremely fine thermoplastic synthetic fibers that constitute nonwoven fabrics, knitted fabrics or woven fabrics have different structures that make it flame-retardant.

[0006] In response to this issue of flame retardancy, there are proposals to use organophosphorus copolymerized polyester in the fine fibers of artificial leather (for example, see Patent Document 1); or to use polyurethane polymer elastomer copolymerized with organophosphorus components in the polymer elastomer of artificial leather (for example, see Patent Document 2); or to attach or absorb diaryl aminophosphate flame retardant into the fine fibers (for example, see Patent Document 3).

[0007] Alternatively, there are proposals for: a method of applying a matrix layer composed of flame-retardant and heat-resistant fibers to the back surface and then complexing it (e.g., see Patent Document 4); or a method of partially applying a flame-retardant coating in an area ratio of 60-90% to ensure adequate breathability when the back surface of the artificial leather is coated with a flame-retardant (e.g., see Patent Document 5); and a method of forming ventilation holes penetrating the artificial leather (e.g., see Patent Document 6). [Prior Art Documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2002-115183 [Patent Document 2] Japanese Patent Application Publication No. 2002-201574 [Patent Document 3] Japanese Patent Application Publication No. 2012-229508 [Patent Document 4] Japanese Patent Application Publication No. 2014-25156 [Patent Document 5] Japanese Patent Publication No. 2013-520581 [Patent Document 6] International Publication No. 2014 / 097999 [Summary of the Invention]

[0009] (The problem that the invention aims to solve)

[0010] The technology disclosed in Patent Document 1, compared to polyester commonly used in microfibers, results in reduced spinnability and dye staining during manufacturing due to the copolymerization of organophosphorus components. Furthermore, because the fiber strength of microfibers or the rubbing fastness of artificial leather are reduced, it is difficult to use in applications requiring high light resistance and high abrasion resistance.

[0011] The technology disclosed in Patent Document 2, in order to prevent deterioration over the years and to give artificial leather strength and feel, involves copolymerizing the polyurethane component, which is an important component, with an organophosphorus component. Compared with ordinary polyurethane, this design reduces the feel and durability.

[0012] The technology disclosed in Patent Document 3, when the above-mentioned diarylaminophosphate flame retardant is applied without the use of an adhesive, will cause the flame retardant to fall off during use, resulting in unstable flame retardancy. On the other hand, when an adhesive is used for attachment, the surface of the artificial leather becomes hard to the touch. Moreover, as disclosed in the prior art of Patent Document 3, when a water-soluble flame retardant such as guanidine phosphate is applied to the entire artificial leather, the napped surface absorbs moisture, and during the drying process, the guanidine phosphate dissolves and migrates to the surface due to the moisture, resulting in a ring-shaped staining phenomenon, the so-called "watermark," which causes significant damage to the design of the artificial leather.

[0013] The technology disclosed in Patent Document 4 requires that the flame-retardant heat-resistant fibers be set to a sufficient basis weight in order to ensure a certain degree of flame retardancy. This reduces the density of the complexed structure of the artificial leather, which can easily damage its elegant appearance and soft feel. The same problems also exist with methods that insert the fibers into the interior for integrated complexation and methods that blend flame-retardant heat-resistant fibers into the constituent fibers.

[0014] The technology disclosed in Patent Document 5 cannot achieve sufficient flame retardancy because the flame retardant is applied in a dot matrix pattern, and the prepared artificial leather is not breathable enough, so it cannot simultaneously achieve the density required to present an elegant appearance and the breathability required to cope with, for example, ventilation systems.

[0015] Furthermore, in the technology disclosed in Patent Document 6, when using a punching roller for perforation processing, the debris after perforation is prone to clog the sheet or punching roller, making mass production difficult.

[0016] In summary, the technologies disclosed in Patent Documents 1 to 6, which consist of a fiber complex containing extremely fine fibers that are not easily flame-retardant and a polymer elastomer, cannot provide artificial leather that takes into account both flame retardancy and other important properties (especially moderate breathability, a soft feel like natural suede, and an elegant appearance).

[0017] Therefore, the present invention was made in view of the above-mentioned facts, and its object is to provide: artificial leather with moderate breathability and soft feel, excellent functionality (flame retardancy, etc.), and a touch and elegant appearance similar to natural suede. Furthermore, an artificial leather substrate with good opening-forming properties is provided for obtaining the artificial leather. (Technical means to solve the problem)

[0018] In order to achieve the above-mentioned objective, the inventors conducted in-depth research and found that artificial leather composed of ultra-fine fiber complexes, polymer elastomers and functional agents (such as flame retardants) can provide artificial leather with good formability even when openings are provided, and can take into account both functional properties (such as flame retardancy) and other important properties, by setting the form of the functional agent (such as flame retardant) within a specific range and setting the viscosity of the functional agent (such as flame retardant) within a specific range.

[0019] The present invention is based on these findings and the following inventions are provided according to the present invention.

[0020] The artificial leather of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastomer, wherein one surface has a napped surface and the other surface has a flame-retardant surface with a flame retardant, and satisfies the following requirements 1 and 2: Requirement 1: At least a plurality of openings are provided on the flame-retardant surface. Requirement 2: The viscosity of the flame retardant is 0.1 N / cm² or more and 2.0 N / cm² or less.

[0021] In the preferred form of the artificial leather according to the present invention, the opening ratio of the flame-retardant surface is 1% or more and 40% or less.

[0022] According to a preferred embodiment of the artificial leather of the present invention, the artificial leather is provided with a plurality of openings on the napped surface and the flame-retardant surface, and at least one portion of the openings is a through opening that extends from the napped surface to the flame-retardant surface.

[0023] According to a preferred embodiment of the artificial leather of the present invention, the fiber complexing system comprising the fiber complex containing extremely fine fibers is integrally formed with the knitted / woven fabric (a).

[0024] According to a preferred embodiment of the artificial leather of the present invention, the flame-retardant surface is formed by laminating knitted / woven fabric (b).

[0025] According to the preferred form of the artificial leather of the present invention, the presence ratio of the flame retardant in the thickness direction satisfies the following formula: 0.001≦W / W0≦0.7 where W is the thickness (mm) of the flame retardant surface where the flame retardant is present; W0 is the thickness (mm) of the entire artificial leather.

[0026] In the preferred form of the artificial leather according to the present invention, the flame retardant is a phosphorus compound.

[0027] In the preferred form of the artificial leather according to the present invention, the density of the fiber complex containing the above-mentioned polymeric elastomer is 0.20 g / cm3 or more and 0.50 g / cm3 or less.

[0028] Furthermore, the method for manufacturing artificial leather of the present invention involves coating one surface of a pile sheet-like material composed of a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, with a flame retardant having an adhesive strength of 0.1 N / cm2 or more and 2.0 N / cm2 or less to form a flame retardant surface, and at least a plurality of openings are provided on the flame retardant surface.

[0029] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastomer; wherein one surface has a napped surface and the other surface has a functional surface with a functional agent; wherein the viscosity of the functional agent is 0.1 N / cm² or more and 2.0 N / cm² or less. Furthermore, the artificial leather substrate can be made into the artificial leather of the present invention simply by forming an opening, but it can also be used as artificial leather on its own.

[0030] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer; wherein one surface has a napped surface and the other surface has a functional surface with a functional agent; wherein the coefficient of kinetic friction of the functional surface is 0.15 or more and 0.60 or less, and the stiffness of the artificial leather substrate is 30 mm or more and 150 mm or less.

[0031] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastomer; wherein one surface has a napped surface and the other surface has a functional surface with a functional agent; wherein the amount of the functional agent attached is 2 to 30% by mass relative to the artificial leather substrate. (Effects compared to prior art)

[0032] According to the present invention, artificial leather with moderate breathability and soft feel, excellent functionality (flame retardancy, etc.), and a touch and elegant appearance similar to natural suede can be obtained. Furthermore, an artificial leather substrate with good opening-forming properties for obtaining the artificial leather can be obtained.

Implementation Method

[0033] The artificial leather of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastomer, wherein one surface has a napped surface and the other surface has a flame-retardant surface with a flame retardant, and satisfies the following requirements 1 and 2: Requirement 1: At least a plurality of openings are present on the flame-retardant surface. Requirement 2: The viscosity of the flame retardant is 0.1 N / cm² or more and 2.0 N / cm² or less.

[0034] The fine fibers contained in the fiber complex are preferably 60% or more, and more preferably 80% or more by weight.

[0035] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, wherein one surface has a napping surface and the other surface has a functional surface with a functional agent; wherein the viscosity of the functional agent is 0.1 N / cm2 or more and 2.0 N / cm2 or less.

[0036] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, wherein one surface has a napped surface and the other surface has a functional surface with a functional agent; wherein the coefficient of dynamic friction of the functional surface is 0.15 or more and 0.60 or less, and the stiffness of the artificial leather is 30 mm or more and 150 mm or less.

[0037] The artificial leather substrate of the present invention comprises: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, wherein one surface has a napped surface and the other surface has a functional surface with a functional agent; wherein the amount of the functional agent attached is 2 to 30% by mass relative to the artificial leather substrate. Hereinafter, these constituent elements will be described in detail, but the present invention is not limited to the scope described below without departing from its spirit.

[0038] [Fiber Complex] The fiber complex system constituting the artificial leather of the present invention comprises extremely fine fibers, with an average single fiber diameter of 0.1 μm or more and 10 μm or less. By setting the average single fiber diameter of the extremely fine fibers to 0.1 μm or more, preferably 1.5 μm or more, excellent color development after dyeing, lightfastness, rubbing fastness, and stability during spinning can be achieved, and artificial leather with strength capable of withstanding actual use can be obtained. On the other hand, by setting it to 10.0 μm or less, preferably 6.0 μm or less, and more preferably 4.5 μm or less, artificial leather with softness, density, soft touch, and excellent surface appearance quality can be obtained.

[0039] The "average single fiber diameter of the ultrafine fiber" in this invention is calculated by taking a scanning electron microscope (SEM) image of the cross-section of artificial leather, randomly selecting 10 round or nearly round elliptical ultrafine fibers, measuring the single fiber diameter, and calculating the arithmetic mean of the 10 fibers, rounding to the second decimal place. However, when using ultrafine fibers with irregular cross-sections, the cross-sectional area of ​​the single fiber is measured first, and the diameter of the single fiber is obtained by calculating the diameter when the cross-section is regarded as a circle.

[0040] The ultrafine fibers constituting the fiber complex of the artificial leather of the present invention can be various synthetic fibers including: polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, poly(p-hydroxyethyl)cyclohexyldimethyl 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. From the viewpoint of superior strength, dimensional stability, lightfastness, and dyeability, polyester fibers including polymers such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate are preferred. Furthermore, ultrafine fibers of different materials can also be mixed in the fiber complex without compromising the purpose of the present invention.

[0041] From the point of view of processing operability, the cross-sectional shape of the ultrafine fiber is preferably circular, but it can also be: elliptical, flat and triangular polygonal shapes; fan-shaped and cross-shaped, hollow, Y-shaped, T-shaped and U-shaped irregular cross-sections.

[0042] In the extremely fine fibers constituting the fiber complex, inorganic particles such as titanium oxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents may also be added for various purposes.

[0043] In order to achieve excellent dark color development, the resin constituting the ultrafine fiber can be a polyester resin, and the polyester resin contains pigment with an average particle size of 0.05 μm or more and 0.20 μm or less. The term "particle size" here refers to the particle size of the pigment in the ultrafine fiber, which is generally called "secondary particle size". By setting the average particle size to 0.05 μm or more, preferably 0.07 μm or more, the pigment is trapped inside the ultrafine fiber, thus preventing it from falling off the ultrafine fiber. Furthermore, by setting it to 0.20 μm or less, preferably 0.18 μm or less, and more preferably 0.16 μm or less, it can achieve excellent stability and fiber strength during spinning. The average particle size is calculated according to the following method. (1) An ultrathin slice with a thickness of 5 to 10 μm is made in the cross-sectional direction perpendicular to the long side of the ultrafine fiber. (2) The fiber cross-section in the ultrathin section was observed using a transmission electron microscope (TEM) at 10,000x magnification. (3) Using image analysis software, the equivalent circle diameter of the pigment particles at 20 locations within a 2.3μm × 2.3μm field of view was determined. If there were fewer than 20 locations with pigment particles in the 2.3μm × 2.3μm field of view, the equivalent circle diameter of all existing pigment particles was determined. (4) The average value (arithmetic mean) of the 20 measured particle sizes was calculated.

[0044] In order to achieve excellent dark color development properties, the present invention uses a polyester resin as the resin constituting the ultrafine fibers, and the polyester resin contains pigment. The pigment content in the polyester resin forming the ultrafine fibers is preferably 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 properties can be 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, artificial leather with high physical properties such as strength can be obtained. The pigment system can be carbon-based black pigments such as carbon black or graphite; or oxide-based black pigments such as iron(III) oxide or copper-chromium composite oxide. From the viewpoint of easily obtaining finer particle sizes and excellent dispersibility with polymers, carbon black is preferred. Colored microparticle oxide pigments can use known pigments that closely resemble the target color, such as: iron oxide (e.g., Dai Nippon Seika Co., Ltd.'s "TM YELLOW 8170"), iron oxide (e.g., Dai Nippon Seika Co., Ltd.'s "TM RED 8270"), cobalt aluminate (e.g., Dai Nippon Seika Co., Ltd.'s "TM BLUE 3490E"), etc.

[0045] One of the constituent elements of the artificial leather of the present invention is a fiber complex containing extremely fine fibers. Examples of fiber complex systems include knitted fabrics, woven fabrics, and non-woven fabrics. Furthermore, these fiber complexes contain polymeric elastomers inside or outside, and can be appropriately differentiated according to the cost and characteristics required for each application or purpose. From a cost perspective, knitted and woven fabrics are preferred; from the perspective of a substantial feel or the appearance quality created by micro-pilling, fiber complexes filled with non-woven fabrics or polymeric elastomers are preferred.

[0046] When the fiber complexing system uses knitted / woven fabrics, examples of knitted fabrics include plain weave, woven fabric, satin weave, and various knitted fabrics based on such knitted structures. Furthermore, examples of woven fabrics include warp knitting, weft knitting represented by Tricot warp knitting, patterned knitting, and various woven fabrics based on such knitting structures.

[0047] When using nonwoven fabrics in a fiber complexation system, the following types of nonwoven fabrics can be applied: general short-fiber nonwoven fabrics, long-fiber nonwoven fabrics, needle-punched nonwoven fabrics, paper-woven nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, and electrospun nonwoven fabrics, etc., and all nonwoven fabrics listed in various categories. Here, from the viewpoint of having a substantial hand feel or an appearance quality caused by fine napping, nonwoven fabrics are preferred.

[0048] In the view of superior durability or abrasion resistance of artificial leather, it is preferable to use polymeric elastomers containing polymers either inside or outside the fibrous complex. In particular, from the point of view of flexibility, it is preferable to contain a polymer elastomer inside the fibrous complex.

[0049] Furthermore, the artificial leather of the present invention, from the viewpoint of excellent mechanical strength, preferably makes the fiber ligature integrated with the knitting / braid (a) in ligation. Preferably, the fiber complex is a nonwoven fabric and contains a knit / braid (a) within it. Even better, the fiber joint is a non-woven fabric, and the knit / braid (a) is a knit, which enables the balance of appearance, flexibility, and strength to be optimal.

[0050] In the above-mentioned knit / braid (a) that is integrated with the fiber complex, the yarn constituting the knit / braid (a) is preferably using a synthetic fiber comprising: polyester, polyamide, polyethylene, or polypropylene, or a copolymer class thereof. Wherein, synthetic fibers constituted of polyester, polyamide and such copolymers may be used alone or in complexes or in mixtures. Also, the yarns constituting the knitting / braid (a) are available: raw yarns, plus yarns, and blends of raw yarns and short fibers. From the point of view of durability, especially mechanical strength, it is better to use multifilaments constructed of polyester-based resins or polyamide-based resins.

[0051] By setting the average single fiber diameter of the fibers constituting the above knitting / braid (a) below 50.0 μm, preferably less than 15.0 μm, and preferably less than 13.0 μm, not only can an artificial leather with excellent softness be obtained, even if the surface of the artificial leather has fibers of exposed knitted / braided material, the chromaticity and surface chromaticity is not even small after dyeing with the extremely fine fibers containing pigments. On the other hand, by setting the average single fiber diameter of the fibers constituting the knitting / braid (a) to be above 1.0 μm, preferably above 8.0 μm, and preferably above 9.0 μm, the morphological stability of the product when used as artificial leather can be improved. The average single fiber diameter of the fibers constituting the knitting / braid (a) above was calculated by taking a scanning electron microscope (SEM) photograph of the artificial leather section, randomly selecting 10 fibers constituting the knitting, determining the single fiber diameter of those fibers and calculating the arithmetic mean of 10, rounding to the second decimal place. When the fibers constituting the knitting / braid (a) above are complex yarns, the total fineness of the compound yarns is determined according to "8.3.1 Metric Fiberness b) B (Simplified Method)" of "8.3 Fiberness" of JIS L1013:2010 "Test Methods for Chemical Fiber Raw Silk Yarns", preferably set to above 30dtex and below 170dtex. By setting the total fibers of the yarns constituting the knit / braid (a) described above to less than 170dtex, artificial leather with excellent flexibility is obtained. On the other hand, by setting the total fineness to more than 30dtex, not only can the stability of the product form as artificial leather be improved, but when the fiber joint is set as a non-woven fabric, when the knitting / braid (a) is integrated using needle rolling, etc. When the knit / braid (a) is a knit, the better total fiber of the complex yarn of the warp and the weft is set to the same total fiber. Also, the number of yarns constituting the above knitting is preferably set to more than 1000T / m and less than 4000T / m. By setting the pin number below 4000T / m, preferably below 3500T / m, preferably below 3000T / m, artificial leather with excellent softness can be obtained is above 1500T / m, preferably above 2000T / m, when the use of needle rolling, etc. to make the non-woven fabric and knitted knitted integrated, can prevent the fiber constituent knitted fiber damage, so that the artificial leather has excellent mechanical strength.

[0052] The knitted / knitted fabric (a) described above may also be a knitted / knitted fabric containing two or more polymers compounded into parallel or eccentric core-sheath type composite fibers (hereinafter sometimes referred to as "parallel type composite fibers"). For example, parallel type composite fibers containing two or more polymers with different intrinsic viscosities (IV) will cause stress concentration on the high viscosity side during stretching, resulting in 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 step, generating strain within the single fiber and exhibiting three-dimensional coil-like curling. This three-dimensional coil-like curling results in the elasticity exhibited when used as artificial leather.

[0053] When the fiber complex is made of nonwoven fabric, a uniform and pleasant appearance or feel can be obtained when the surface is napped. The nonwoven fabric can be in the form of long-fiber nonwoven fabric mainly composed of raw filaments, or short-fiber nonwoven fabric mainly composed of fibers less than 100mm. When the fibrous substrate is made of long-fiber nonwoven fabric, artificial leather with excellent strength can be obtained, which is preferable. On the other hand, when it is made of short-fiber nonwoven fabric, compared to long-fiber nonwoven fabric, the number of fibers aligned in the thickness direction of the artificial leather can be increased, and when napping is applied, the surface of the artificial leather can have a higher density.

[0054] When using short-fiber nonwoven fabric, the fiber length of the ultrafine fibers is preferably 25mm or more and 90mm or less. By setting the fiber length to 90mm or less, preferably 80mm or less, and even more preferably 70mm or less, good appearance quality and feel can be achieved. On the other hand, by setting the fiber length to 25mm or more, preferably 35mm or more, and even more preferably 40mm or more, artificial leather with excellent abrasion resistance can be achieved.

[0055] The basis weight of the fiber complex comprising extremely fine fibers constituting the artificial leather of the present invention is determined according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General Nonwoven Fabrics Test Methods", preferably in the range of 50 g / m2 or more and 600 g / m2 or less. By setting the basis weight of the above-mentioned nonwoven fabric to 50 g / m2 or more, preferably 100 g / m2 or more, artificial leather with a substantial feel and excellent hand feel can be obtained. On the other hand, by setting it to 600 g / m2 or less, preferably 450 g / m2 or less, artificial leather with excellent formability and softness can be obtained. Even when the knitted / woven fabric (a) is integrated into the fiber complex, the basis weight of the fiber complex is preferably still within the above-mentioned basis weight range.

[0056] [Polymer Elastomer] The artificial leather of the present invention contains a polymer elastomer. Preferably, the polymer elastomer is contained within the fiber complex. By containing the polymer elastomer internally, the softness, morphological stability, or abrasion resistance of the artificial leather can be improved. This polymer elastomer system differs from functional agents (flame retardants, etc.) described later, and must serve as a binder for the fiber complex.

[0057] The aforementioned polymeric elastic system may use, for example, polyurethane, styrene-butadiene rubber (SBR), nitrile rubber (NBR), and acrylic resin, wherein, preferably, polyurethane is used as the main component. By using polyurethane, artificial leather with a feel and elegant appearance similar to natural suede, as well as physical properties capable of withstanding actual use, can be obtained.

[0058] In the polyurethane forming the polymer elastomer, it is preferable to contain 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.

[0059] The term “particle size” here refers to the particle size of the black pigment (b) when it exists in the polymer elastomer, and is generally referred to as “secondary particle size”.

[0060] By setting the average particle size to 0.05 μm or more, preferably 0.07 μm or more, the black pigment (b) is trapped inside the polymer elastomer, thus preventing it from detaching from the ultrafine fibers. Furthermore, by setting it to 0.20 μm or less, preferably 0.18 μm or less, and even more preferably 0.16 μm or less, excellent dispersibility can be achieved when impregnating the polymer elastomer.

[0061] If the particle size variation coefficient (CV) is 75% or less, better 65% or less, better 60% or less, exceptionally good 55% or less, or best 50% or less, the particle size distribution can be reduced, and smaller particles can be prevented from falling off the surface of the polymer elastomer or obvious aggregated particles can be precipitated in the impregnation tank.

[0062] In this invention, the average particle size and the coefficient of variation (CV) are calculated according to the following method. (1) An ultrathin section with a thickness of 5~10μm is prepared in the cross-sectional direction perpendicular to the long side of the artificial leather. (2) The cross-section of the polymer elastomer in the ultrathin section is observed at 10000x magnification using a transmission electron microscope (TEM). (3) Using image analysis software, the equivalent circle diameter of the black pigment (b) particles contained in 20 locations in the 2.3μm×2.3μm field of view is measured. When there are fewer than 20 locations of black pigment (b) particles in the 2.3μm×2.3μm field of view, the equivalent circle diameter of all black pigment (b) particles present is measured. (4) The average value (arithmetic mean) and the coefficient of variation (CV) are calculated for the particle size at the 20 locations measured. In addition, in this invention, the coefficient of variation is calculated by the following formula: Coefficient of variation of particle size (%) = (standard deviation of particle size) / (arithmetic mean of particle size) × 100.

[0063] The black pigment (b) in this invention can be: carbon-based black pigments such as carbon black or graphite; or oxide-based black pigments such as iron oxide, copper-chromium composite oxide, etc. From the viewpoint of easily obtaining finer particle sizes and excellent dispersibility with polymers, carbon black is preferred as the black pigment.

[0064] The polyurethane used in this invention can be either organic solvent-based polyurethane used in a dissolved state or water-dispersible polyurethane used in a dispersed state. Furthermore, the polyurethane used in this invention is preferably a polyurethane obtained by reacting a high molecular weight glycol, an organic diisocyanate, and a chain elongating agent.

[0065] The aforementioned polymeric diol system may include, for example, polycarbonate diols, polyester diols, polyether diols, polysiloxane diols, and fluorinated diols, or copolymers of these combinations. Among these, from the viewpoint of hydrolysis resistance and abrasion resistance, polycarbonate diols are preferred.

[0066] The above-mentioned polycarbonate diol system can be manufactured by transesterification reaction of alkyl diol with carbonate, or by reaction of phosgene or chloroformate with alkyl diol.

[0067] Furthermore, examples of alkyldiols include: straight-chain alkyldiols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol; or branched alkyldiols such as neopentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanediol; aromatic diols such as bisphenol A; glycerol, trimethylolpropane, and pentaerythritol. The present invention can employ any one of the following: polycarbonate diols obtained from individual alkyldiols, and copolymerized polycarbonate diols obtained from two or more alkyldiols.

[0068] Furthermore, polyester diols can be exemplified by polyester diols obtained by condensing various low molecular weight polyols with polyacids.

[0069] The low molecular weight polyol system may use, for example, one or more of the following: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 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, 1,4-cyclohexanediol, and 1,4-cyclohexanediol.

[0070] Furthermore, adducts that cause bisphenol A to add to various epoxides may also be used.

[0071] Furthermore, examples of polyacid systems include one or more of the following: succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, p-phthalic acid, and hexahydroisophthalic acid.

[0072] Examples of polyether diols used in this invention include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols in combination with the like.

[0073] The number average molecular weight of the polymer glycol is preferably in the range of 500 or higher and 4000 or lower when the molecular weight of the polyurethane elastomer is constant. By setting the number average molecular weight to preferably 500 or higher, and more preferably 1500 or higher, the hardening of artificial leather can be prevented. Furthermore, by setting the number average molecular weight to 4000 or lower, and more preferably 3000 or lower, the strength of polyurethane can be maintained.

[0074] Examples of the organic diisocyanates used in this invention include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and phenyl diisocyanate; or aromatic diisocyanates such as diphenylmethane diisocyanate and methyl phenyl diisocyanate, and combinations thereof may also be used.

[0075] Preferably, the chain elongating agent can be an amine-based chain elongating agent such as ethylenediamine or methylenebisphenylamine; or a diol-based chain elongating agent such as ethylene glycol. Furthermore, polyamines obtained by reacting polyisocyanate with water can also be used as chain elongating agents.

[0076] The polyurethane used in this invention may also be used 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 pre-introduced into the polyurethane molecular structure as a crosslinking reaction site. From the viewpoint that crosslinking points can be formed more uniformly within the polyurethane molecular structure and that this reduces the decrease in flexibility, an internal crosslinking agent is preferred.

[0077] The crosslinking agent can be a compound having: isocyanate group, acezoline group, carbodiimide group, epoxy group, melamine resin, and silicone group, etc.

[0078] Furthermore, various additives may be included in polymer elastomers for various purposes, such as: flame retardants such as "phosphorus-based, halogen-based and inorganic-based"; antioxidants such as "phenol-based, sulfur-based and phosphorus-based"; ultraviolet absorbers such as "benzotriazole-based, diphenyl ketone-based, salicylate-based, cyanoacrylate-based and oxaloacetamide-based"; light stabilizers such as "hindered amine-based or benzoate-based"; hydrolysis stabilizers such as polycarbodiimide; plasticizers, antistatic agents, surfactants, coagulation regulators and dyes, etc.

[0079] Generally, the content of the aforementioned polymeric elastomer in artificial leather can be appropriately adjusted considering the type of polymeric elastomer used, the manufacturing method of the polymeric elastomer, and its feel or physical properties. However, in this invention, the content of the polymeric elastomer is preferably 10% by mass or more and 60% by mass or less relative to the mass of the fiber complex. By setting the aforementioned polymeric elastomer content to 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more, the bonding between fibers by the polymeric elastomer can be strengthened, thereby improving the abrasion resistance of the artificial leather. On the other hand, by setting the aforementioned polymeric elastomer content to 60% by mass or less, preferably 45% by mass or less, and more preferably 40% by mass or less, the softness of the artificial leather can be increased.

[0080] According to the preferred form of the artificial leather of the present invention, the density of the fiber complex containing the aforementioned polymeric elastomer, that is, the density of the fiber complex containing the polymeric elastomer (excluding the density of the artificial leather excluding the knitted / woven fabric (b) and flame retardant described later), is preferably 0.20 g / cm3 or more and 0.50 g / cm3 or less. By setting the density to 0.20 g / cm3 or more, preferably 0.25 g / cm3, the artificial leather can have sufficient morphological stability, dimensional stability, and strength. Furthermore, the artificial leather can be made dense, and the opening can be a neat opening without any tearing or other defects. On the other hand, by setting the density to 0.50 g / cm3 or less, preferably 0.45 g / cm3 or less, the artificial leather can have good breathability and softness.

[0081] [Functional Agents (Flame Retardants, etc.)] The functional agents used in this invention refer to preparations that impart functional properties to fiber products, such as flame retardancy, stain resistance, yellowing resistance, NOx resistance, slip resistance, water repellency, oil repellency, color migration resistance, abrasion resistance, odor control, durability, softness, and elasticity. The functional agents (flame retardants, etc.) used in the artificial leather of this invention have a viscosity of 0.1 N / cm² or more and 2.0 N / cm² or less. By setting the viscosity of the above-mentioned functional agents (flame retardants, etc.) to 0.10 N / cm² or more, preferably 0.15 N / cm² or more, and more preferably 0.20 N / cm² or more, when the functional agents (flame retardants, etc.) are applied and dried, the functional agents (flame retardants, etc.) can be fixed to the fiber complex with sufficient adhesion, and the dried functional agents (flame retardants, etc.) will not fall off even at high temperatures. By setting the viscosity to 2.00 N / cm² or less, preferably 1.60 N / cm² or less, and even more preferably 1.00 N / cm² or less, the opening will not be blocked by fiber debris composed of fibers, polymer elastomers, and functional agents (such as flame retardants) after the opening is formed, thus ensuring good opening formation. Furthermore, even if perforations occur during opening formation, the needle holes will not be blocked by fiber debris, allowing for continuous processing. Additionally, the structure of uniformly dispersed and adhered functional agents (such as flame retardants) results in a soft feel to the artificial leather. In this invention, the viscosity of the functional agent (such as flame retardants) refers to a value obtained by measurement and calculation as follows: (1) The functional agent (such as flame retardants) is heated to 60°C. (2) Using a viscosity meter, a stainless steel probe (contact pressure 24.5 N / cm²) is pressed onto the functional agent (such as flame retardants) at a speed of 6 mm / min and held for 5 seconds. (3) After (2), read the maximum load when tearing at 6 mm / min. (4) Repeat (2) to (3) 5 times, and round the arithmetic mean of the obtained values ​​to the third decimal place.

[0082] Furthermore, in order to reliably obtain the aforementioned adhesion, opening properties, and softness even with temperature changes, the viscosity of the functional agent (flame retardant, etc.) when heated to 40°C is preferably 0.05 N / cm² or more and 1.00 N / cm² or less, and more preferably 0.01 N / cm² or more and 0.50 N / cm² or less at 20°C. In particular, regarding the viscosity at 20°C, the lower the surface adhesion of the functional surface (flame retardant, etc.), the better, in terms of the handling properties of artificial leather sheets at room temperature, such as forming or sewing. By setting the viscosity of the functional agent within the above range, the resistance when the artificial leather is released from the roller is reduced, and the handling properties of the artificial leather can be improved in the next step of the operation. In addition, the viscosity measurement of the functional agent (flame retardant, etc.) when heated to 40°C or 20°C is performed in the same manner as above, except that the heating in (1) is changed to 40°C or 20°C.

[0083] The functional agent (flame retardant, etc.) may also be a resin itself composed of a polymer compound having functional functional groups. However, in addition to low molecular weight compounds having functional components (flame retardant components, etc.), it is preferable to contain a resin in order to obtain functional durability. The resin is selected from, for example, acrylic resin, ethyl carbamate resin, polyester resin, vinyl acetate resin, etc., without particular limitation. From the viewpoint of adhesion and heat resistance to fiber complexes or knitted / woven fabrics, acrylic resin with good balance is preferred. The amount of the adhesive resin is not limited to a specific value. It is preferable to use a range of 5 to 50% by mass relative to the total mass of functional components (flame retardant components, etc.) contained in the functional agent (flame retardant, etc.). If it is less than 5% by mass, the flame retardant is prone to powder component shedding. If it exceeds 50% by mass, there is a possibility of impairing the feel of the artificial leather. From the viewpoint of adhesion, it is preferable to use a resin with low rubber elasticity. For example, regarding acrylic resins, acrylamide resins have better adhesion than acrylonitrile resins, making them superior. Furthermore, most resins generally have a hard feel; reducing the amount of resin used can soften the feel. Using ethylene-vinyl acetate resin, which has higher adhesion, can improve adhesion and tack even in small amounts. Therefore, when reducing the amount of resin used, resins containing ethylene-vinyl acetate are preferable.

[0084] When the functional agent is a flame retardant and the combustion mode is set to carbonization, the resin of the flame retardant can also be other resins that will not affect the formation of carbides such as vinyl acetate or vinyl acetate copolymer resin, such as acrylic resin, SBR resin, and MBR resin. In particular, if the flame retardant further contains acrylic resin, it can improve the softness of the hand feel and the water resistance of the flame retardant.

[0085] There are no particular restrictions on the types of flame-retardant components of the flame retardant. From the perspective of water marks, it is preferably water-insoluble or hardly water-soluble. The so-called "water mark" here refers to artificial leather to which a flame retardant is applied. When water droplets are attached to either side of the front and back surfaces and then naturally dried, white spots or stains appear in the wetted part. From the perspective of meeting current environmental hormone regulations, it is preferably a dehalogenated one. Examples of dehalogenated flame retardants include phosphorus-containing compounds, nitrogen-containing compounds, phosphorus-nitrogen compounds, sulfonamide compounds, phosphorus-sulfonamide compounds, sulfur-nitrogen-containing compounds, etc. These can be used alone or in combination of multiple ones. From the perspective of flame retardant performance, phosphorus compounds are preferred. Examples of phosphorus compounds include guanidine phosphate, phosphoric acid urethane, phosphate esters, phosphoric acid ester amides, ammonium polyphosphate, triphenyl phosphate, tris(dimethylphenyl) phosphate and other aromatic phosphate esters, etc. Particularly preferred is ammonium polyphosphate-based flame retardant with a relatively high phosphorus content. Also, in order to make it hardly water-soluble, it is preferably a type coated with melamine resin or silica-based resin. Inorganic flame retardants can use known flame retardants such as aluminum hydroxide, titanium oxide, zinc oxide, expandable graphite, magnesium hydroxide, calcium carbonate, zinc borate, ammonium polyphosphate, and red phosphorus. It is preferably to use polyphosphate-based flame retardants with excellent processability and durability.

[0086] The combustion mode of the flame retardant includes a carbonization type that forms a carbonized film and a melting type that makes the fire source drop, but it is not limited to any mode. In the flame retardant evaluation under sufficient flame retardant conditions, from the perspective of flame retardant stability, the melting type is preferred.

[0087] The flame retardant evaluation of the artificial leather of the present invention is based on the combustion test specification (horizontal burning speed) of automotive interior materials in the Federal Motor Vehicle Safety Standard (FMVSS), No. 302. A horizontal holding test piece (350 mm × 100 mm) is ignited with a 38 mm flame for 15 seconds, and the burning speed from the A mark to the B mark for 254 mm is judged according to the following criteria. ・In the case of self-extinguishing before reaching the A mark, the judgment category is set as "non-combustible" and it is evaluated as qualified. ・In the case of self-extinguishing after exceeding the A mark, when the burning distance is within 50 mm and the burning time is within 60 seconds, the judgment category is set as "self-extinguishing" and it is evaluated as qualified. ・In the case of not self-extinguishing, but the burning speed between the marks is below 4 inches / minute (about 101.6 mm / min), the judgment category is set as "burning below the specified speed" and it is evaluated as qualified. ・In the case of not self-extinguishing and the burning speed between the marks exceeding 4 inches / minute (about 101.6 mm / min), the judgment category is evaluated as "burning exceeding the specified speed" and it is evaluated as unqualified.

[0088] Furthermore, for example, when applying a carbonized agent such as a stain repellent to artificial leather, by making the flame retardant carbonized, the amount of carbonization can be increased, resulting in good flame retardancy, which can be combined with the material of the artificial leather to form a selected combustion mode. When a carbonized flame retardant is selected, by choosing a resin that is easy to carbonize, the aforementioned flame retardant components can be reduced, which is better in terms of cost. For example, a vinyl-containing resin that can generate a carbonized skeleton during combustion.

[0089] The vinyl resin system includes at least one selected from vinyl acetate resin, ethylene-vinyl acetate copolymer resin, acrylic-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, and branched fatty acid ethylene-vinyl acetate copolymer resin. The carbides generated from these vinyl acetates, or from the combination of vinyl acetate copolymer resins and phosphorus compounds, promote flame retardancy, and are particularly preferred in terms of effectively enhancing the flame retardancy properties of artificial leather against horizontal burning.

[0090] The amount of flame retardant applied must be determined from the perspective of ensuring the necessary flame retardant properties and reducing hand stiffness. It should be increased or decreased according to the basis weight, thickness, fine fibers, polymer type of the elastomer, and fiber complex type of the artificial leather. From the perspective of balancing flame retardancy and hand feel, it is preferable to contain 2-30% by mass relative to the artificial leather. The amount of flame retardant applied is preferably 10-200 g / m², more preferably in the range of 20-100 g / m². The amount of flame retardant applied can be calculated, for example, from the mass after application minus the mass before application, or from the artificial leather after application, or by elemental peak analysis such as fluorescence X-ray diffraction.

[0091] From the viewpoint of coating penetration, the solution used to apply the flame retardant to artificial leather preferably has a viscosity of 500-10000 mPa·s at room temperature, and may contain a viscosity modifier if necessary. More preferably, the viscosity is 1500-9000 mPa·s, and ideally 2500-7000 mPa·s. This allows for a better range of the thickness direction of the flame retardant, resulting in softer artificial leather with higher flame retardancy. There is no particular limitation on the method for measuring the viscosity of the solution; a standard method using a rotational viscometer can be employed. From the viewpoint of preventing watermark formation, the viscosity modifier used to adjust the viscosity of the solution is preferably sparingly soluble in water, such as an alkali-thickening acrylic resin or ethylene oxide higher fatty acid ether.

[0092] In this invention, in addition to the above-mentioned components, aluminum hydroxide, magnesium hydroxide, metal oxides, etc. may also be used as flame retardant additives in the flame retardant.

[0093] The amount of attachment of functional agents (refractory agents, etc.), from the point of view of ensuring necessary functional properties, and reducing hand hardening, must be determined by the opening of the artificial leather substrate, according to the base weight, thickness, extremely fine fibers, polymer types of polymer elastomers, and fiber complexes of artificial leather. The imparting amount of functional agents (refractory agents, etc.) is preferably in the range of 10~200g / m2, and more preferably in the range of 20~100g / m2.

[0094] [Knitted / braided (b)] The above functional surfaces (refractory equal facets) of the artificial leather of the present invention are, preferably, faces made of a build-up of knitted / braided (b). That is, on the functional surface (refractory, etc.) side of the opposite side of the velvet surface of the artificial leather, the artificial leather can be made as having a stronger strength or combined with a softness by setting further to the state of the fiber bonded volume layer knit / braid (b). In this case, as described above, the fiber complex may also contain a knit / braid (a), which may be selected in conjunction with the respective purposes of the knit / braid (a), knit / braid (b).

[0095] The type of knitting / braid used in the present invention may adopt: a weft braid represented by a warp knit or a Tricot warp braid; a floral braid and various braids based on such braiding;

[0096] The types of yarns constituting a knit / braid (b) may be used, for example: raw yarns, added yarns, and blended yarns of raw yarns and short fibers.

[0097] The preferential density of knitted / braided (b) is 0.10g / cm3 or more and 0.60g / cm3 or less. By setting the density of knit / braid (b) to above 0.10g / cm3, preferably above 0.15g / cm3, artificial leather with good form retention can be made. On the other hand, by setting the density of knit / braid (b) to less than 0.60g / cm3, preferably less than 0.50g / cm3, functional agents (refractory agents, etc.) can be penetrated into the interior and can become artificial leather with excellent softness.

[0098] The thickness of the knitted / knitted fabric (b) is preferably 0.10~2.50 mm, more preferably 0.15~1.50 mm, and especially preferably 0.20~1.00 mm. If the thickness of the knitted / knitted fabric (b) is less than 0.10 mm, the processability and strength when laminated with the above-mentioned fiber complex will deteriorate; if the thickness is greater than 2.50 mm, there is a tendency to impair softness and breathability.

[0099] There is no limitation on the method of laminating the fiber complex with the knitted / woven fabric (b), and a bonding method using an adhesive is generally adopted. Examples of adhesives include thermoplastic resins such as polyester resin, copolymer polyester resin, nylon resin, and acrylic resin; or moisture-curing resins such as polysiloxane rubber, polystyrene rubber, and polyurethane resin. Preferably, a thermoplastic resin with excellent processability is used, and nylon resin with excellent hydrolysis resistance is preferred. For artificial leather containing very fine fibers, from the viewpoint of good rubbing fastness, a moisture-curing resin that can be processed with a lower heat resistance is preferred.

[0100] The thickness of the adhesive layer is set within a range that provides sufficient adhesion without compromising the softness and breathability of the artificial leather, preferably 1~300μm.

[0101] When the adhesive is a thermoplastic resin, the softening temperature of the thermoplastic resin is preferably 70~160℃, more preferably 80~120℃. If the softening temperature is below 70℃, softening may occur during processing and actual use; if the softening temperature is above 160℃, the softening treatment during bonding may impair the feel and friction resistance of the artificial leather.

[0102] [Artificial Leather] The artificial leather of the present invention has the above-mentioned fiber complex and the above-mentioned polymer elastomer, and one of its surfaces has a napped surface and the other surface has a flame-retardant surface with the above-mentioned flame retardant.

[0103] First, one surface of the artificial leather of the present invention has a napped surface. That is, napping 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 napping, from the point of view of design effect, the napping shape is preferably such that when a finger slides across it, a mark is left due to the change in the napping direction, that is, the napping length and direction softness to the extent of the so-called "fingerprint". The napping shape is provided on the other surface (back side) of the product surface of the artificial leather. For example, a flame retardant is applied after napping is formed on the back side of the fiber complex. Also, when the back side of the fiber complex is layered with knitted / woven fabric (b), it can be arranged that the front and back sides of the fiber complex are napped, and a flame retardant is applied to the layered knitted / woven fabric (b), so that the napped part on the back side of the fiber complex contains the flame retardant, and the flame retardant surface has a napped shape.

[0104] More specifically, when the surface of the product is a napped surface, the nap length of this 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 nap length to 50 μm or more, the nap is covered with the polymer elastomer, thus preventing the polymer elastomer from being exposed on the surface of the artificial leather product, thereby obtaining an elegant appearance. Furthermore, when the fiber complex constituting the artificial leather contains knitted / woven fabric (a) integrated into it, or when the fiber complex itself is composed of knitted / woven fabric, by setting the nap length within the above range, the knitted / woven fabric structure near the product surface of the artificial leather can be sufficiently covered, thereby obtaining a natural-like elegant appearance, which is preferable in this respect. On the other hand, by setting the nap length to 500 μm or less, artificial leather with excellent design effect and wear resistance can be obtained.

[0105] In this invention, the nap length of the artificial leather is calculated according to the following method. (1) Using a cotton brush or the like, a thin slice with a thickness of 1 mm is made in the direction perpendicular to the long side of the artificial leather cross section, with the nap of the artificial leather in an inverted state. (2) The cross section of the artificial leather is observed at 90x magnification using a scanning electron microscope (SEM). (3) In the SEM image, the height of 10 napped portions (layers composed only of ultrafine fibers) is measured at 200 μm intervals along the width direction of the artificial leather cross section. (4) The average value (arithmetic mean) of the measured heights of the 10 napped portions (layers composed only of ultrafine fibers) is calculated.

[0106] An important feature of the artificial leather of the present invention is that it has a plurality of openings on the aforementioned functional surface (such as the flame retardant surface). The term "opening" in the present invention is not limited to a hole (through opening) formed in the artificial leather from the napped surface to the functional surface (such as the flame retardant surface), but also includes, for example, cases where the knitted / woven fabric (b) and the opening do not overlap in the planar direction and do not constitute a through opening. An example of the latter is the pre-formation of openings on the knitted / woven fabric (b) containing the functional agent (such as the flame retardant), followed by layering onto the fiber complex. The shape of the opening can be any shape to suit the desired design, and can be: circular, elliptical, flat, triangular, or other polygonal shapes; fan-shaped, cross-shaped, hollow, Y-shaped, T-shaped, and U-shaped irregular shapes. There are no particular restrictions on the arrangement of the openings; they can be arranged regularly or irregularly. However, from the perspective of ensuring uniform breathability and strength of the artificial leather as a whole, a regular arrangement at predetermined intervals is preferable. The aperture of the openings, from the perspective of balancing the overall breathability and strength of the artificial leather, is preferably 0.1~3.0mm, and more preferably 0.5~2.5mm.

[0107] Furthermore, in the artificial leather of the present invention, the opening ratio of the aforementioned functional surface (such as the flame retardant surface) is 1% or more and 40% or less, which is preferable from the viewpoint of balancing the overall breathability and strength of the artificial leather. That is, by setting it to 1% or 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, preferably 20% or less, and more preferably 15% or less, an artificial leather with excellent strength can be obtained.

[0108] Furthermore, in the artificial leather of the present invention, it is preferable that the napped surface and the functional surface (such as the flame retardant surface) are each provided with a plurality of openings, and at least one portion of the openings is a through opening that extends from the napped surface to the functional surface (such as the flame retardant surface). This results in an artificial leather with superior breathability.

[0109] The thickness direction shape of the through opening can be, for example, cylindrical, with the same aperture diameter on the napped surface and the functional surface (such as the flame retardant surface), or a mortar-shaped through opening with different aperture diameters on the napped surface and the functional surface (such as the flame retardant surface). That is, the shape of the through opening can be selected considering the design and mechanical properties of the artificial leather.

[0110] In the artificial leather of the present invention, the thickness direction ratio of the above-mentioned functional agent (flame retardant, etc.) preferably satisfies the following formula:

[0111] 0.001≦W / W0≦0.7 Here, W is the thickness (mm) of the functional surface (surface of the flame retardant, etc.) where the functional agent (flame retardant, etc.) exists; W0 is the overall thickness (mm) of the artificial leather. By setting the thickness ratio of the functional agent (flame retardant, etc.) to 0.001 or more, preferably 0.01 or more, and even more preferably 0.05 or more, artificial leather with excellent functionality (flame retardancy, etc.) can be obtained. On the other hand, by setting the thickness ratio of the functional agent (flame retardant, etc.) to 0.7 or less, preferably 0.5 or less, and even more preferably 0.3 or less, artificial leather with excellent breathability and softness can be obtained.

[0112] Furthermore, the thickness ratio of the aforementioned functional agents (flame retardants, etc.) is obtained by taking / preparing three SEM samples, randomly selecting five locations from the observation images of each cross-section, measuring W and W0 at each location, and then calculating W / W0 using the arithmetic mean. When the functional agent (flame retardant, etc.) cannot be specifically identified from ordinary SEM images, a method can be used, for example, to determine whether resin containing elemental peaks is a functional agent using SEM-EDX. For example, in the case of flame retardants, a method can be used to determine whether resin containing phosphorus elemental peaks is a flame retardant.

[0113] Furthermore, from the viewpoint of functionality (flame retardancy, etc.), the preferred form of artificial leather is a layer of knitted / woven fabric (b) on a fiber complex, and a functional agent (flame retardant, etc.) is present on the knitted / woven fabric (b).

[0114] A preferred form of the functional surface (flame retardant, etc.) of artificial leather is that the functional agent (flame retardant, etc.) is present on the surface of the functional surface (flame retardant, etc.), and the area ratio of the functional agent (flame retardant, etc.) on the functional surface (flame retardant, etc.) is 10-100%. The above area ratio is obtained by taking / preparing 3 SEM test samples, randomly selecting 5 locations in the 50x magnification observation image of the surface of each functional surface (flame retardant, etc.), taking SEM images, and after binarization processing, calculating the arithmetic mean of the area ratio of the functional agent (flame retardant, etc.) present relative to the total area after deducting the opening from the 50x image area, and then using the arithmetic mean to calculate. By setting the area ratio to 10% or more, and even better to 30% or more, artificial leather with excellent functionality (flame retardancy, etc.) and stability can be achieved. When polyurethane foam is laminated onto the back of artificial leather, such as in automotive interior materials, the peel strength between the functional surface (flame retardant surface, etc.) and the polyurethane foam can be improved by increasing the smoothness of the functional surface.

[0115] The thickness of the artificial leather of the present invention, as measured by "6.1.1 A" of "6.1 Thickness (ISO Method)" in JIS L1913:2010 "General Nonwoven Fabrics Test Methods", is preferably in the range of 0.2 mm or more and 2.5 mm or less. By setting the thickness of the artificial leather to 0.2 mm or more, preferably 0.3 mm or more, and more preferably 0.4 mm or more, not only is the processability during manufacturing excellent, but it can also become a material with a substantial feel and excellent hand feel. On the other hand, by setting the thickness to 2.5 mm or less, preferably 2.0 mm or less, and more preferably 1.5 mm or less, it can become an artificial leather with excellent formability and softness.

[0116] The artificial leather of the present invention preferably achieves a rubbing fastness of grade 3 or higher according to the "9.1 Rubbing Tester Type I (Rubbing Decolorization Tester) Method" of JIS L0849:2013 "Test Method for Color Fastness to Rubbing" and a lightfastness of grade 3 or higher according to the "7.2 Exposure Method a) First Exposure Method" of JIS L0843:2006 "Test Method for Color Fastness to Xenon Arc Light". By achieving a rubbing fastness and lightfastness of grade 3 or higher, it can prevent color fading or staining of clothing during actual use.

[0117] The artificial leather of the present invention, in the abrasion resistance test determined according to JIS L1096:2010 "Test Methods for Knitted and Braided Fabrics" "8.19 Abrasion Strength and Color Change Due to Friction" "8.19.5 E Method (Martindale Method)", preferably, after 20,000 abrasion cycles with a pressure of 12.0 kPa, the mass reduction of the artificial leather is less than 20 mg, more preferably less than 15 mg, and especially preferably less than 10 mg. By reducing the mass to less than 20 mg, shedding can be prevented during actual use.

[0118] The tensile strength of the artificial leather of the present invention, as measured according to JIS L1913:2010 "Test Methods for General Nonwoven Fabrics" "6.3.1 Tensile Strength and Elongation (ISO Method)", is preferably 20~400 N / cm in any measurement direction. If the tensile strength is 20 N / cm or more, preferably 30 N / cm or more, and more preferably 40 N / cm or more, the artificial leather has excellent morphological stability or durability, and is therefore preferred. Furthermore, if the tensile strength is 400 N / cm or less, preferably 300 N / cm or less, and more preferably 250 N / cm or less, it becomes an artificial leather with excellent formability.

[0119] The artificial leather of the present invention conforms to "8.21 Stiffness" of JIS L1096:2010 "Test Methods for Knitted and Braided Fabrics" and the stiffness measured by the cantilever method is preferably 30~150mm, more preferably 50~130mm, from the viewpoint of feel and softness.

[0120] In JIS L1096:2010 "Test Methods for Knitted and Braided Fabrics", under "8.26 Breathability" Method A (Frazier type method), the artificial leather of the present invention, in order to balance flame retardancy and breathability, has a preferred breathability of 1~400 cm³ / cm² / sec, a more preferred breathability of 20~300 cm³ / cm² / sec, and an especially preferred breathability of 70~250 cm³ / cm² / sec. Furthermore, in the present invention, breathability is greatly affected by the opening, but from the viewpoint of stuffiness or bacterial growth, even those with breathability as fiber complexes are still good. Therefore, the breathability of fiber complexes without openings is preferably 1~100 cm³ / cm² / sec, and more preferably 2~50 cm³ / cm² / sec.

[0121] The basis weight of the artificial leather of the present invention, measured according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General Nonwoven Fabrics Test Method", is preferably in the range of 50 g / m2 or more and 800 g / m2 or less. By setting the basis weight of the above-mentioned nonwoven fabric to 50 g / m2 or more, preferably 100 g / m2 or more, and more preferably 150 g / m2 or more, artificial leather with a substantial feel and excellent hand feel can be obtained. On the other hand, by setting it to 800 g / m2 or less, preferably 600 g / m2 or less, and more preferably 500 g / m2 or less, artificial leather with excellent formability and softness can be obtained.

[0122] The artificial leather substrate used to manufacture the artificial leather with an opening of the present invention, according to JIS L1096:2010 "Test Methods for Knitted and Braided Fabrics" "8.21 Stiffness", and based on the stiffness measured by the cantilever method, from the viewpoint of the feel and softness of the artificial leather after the opening is formed, is preferably 30mm or more and 150mm or less, more preferably 50mm or more and 130mm or less. Furthermore, by setting the stiffness to 30mm or more and 150mm or less, the opening can be easily formed in the artificial leather substrate. When the opening is formed using a hollow perforating chisel, such as a perforating chisel, the artificial leather substrate debris hollowed out in the opening easily falls off from the hollow part of the perforating chisel, resulting in good productivity of the opening forming process.

[0123] The coefficient of kinetic friction of the functional surface of the artificial leather substrate of the present invention, in terms of the formability of the opening and the productivity of the opening forming process, is preferably 0.15 or higher and 0.60 or lower. The coefficient of friction affects the ease of sliding between the functional agent and the opening tool (perforating chisel, hollow needle, drill, etc.) when the opening method involves, for example, perforation (perforating chisel, hollow needle, drill, etc.).

[0124] Regarding the artificial leather substrate of the present invention, in terms of the characteristics of the aforementioned artificial leather, the formation of the aforementioned opening, and the productivity of the opening-forming process, the amount of the functional agent adhering to the artificial leather substrate is preferably 2 to 30% by mass. If the amount of the functional agent adhering is less than 2% by mass, the fiber debris that is hollowed out at the opening of the artificial leather substrate is prone to disperse, and in the case of perforation chiseling, it is not easy to fall off from the hollow portion. Furthermore, if the amount of the functional agent adhering is greater than 30% by mass, for example, in the case of perforation chiseling, the debris is prone to block the hollow portion. The amount of adhering is calculated from the weight change before and after coating, similar to the amount applied, but it can also be calculated using chemical analysis such as fluorescence X-rays.

[0125] [Method for Manufacturing Artificial Leather] The artificial leather of the present invention is preferably manufactured by coating one side of a pile sheet-like material composed of a fiber complex with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, with a flame retardant having an adhesive strength of 0.1 N / cm² or more and 2.0 N / cm² or less to form a flame retardant surface, and the flame retardant surface having at least a plurality of openings. Details of each step will be described below.

[0126] <Steps for Manufacturing Ultrafine Fiber Expressive Fibers> The ultrafine fibers constituting the artificial leather of the present invention can be manufactured using conventional methods, such as island spinning, blending spinning, and split-type composite spinning for synthetic fiber manufacturing. In terms of productivity, such as fiber complex formation, it is preferable to use ultrafine fiber expressive fibers composed of two or more polymeric substances with different solubilities in solvents.

[0127] In the ultrafine fiber expression step, an ultrafine fiber expression fiber is manufactured that forms an island-type composite structure in which an island portion is composed of a resin that becomes ultrafine fibers and a sea portion is formed by an easily soluble polymer.

[0128] The ultra-fine fiber performance fiber system uses thermoplastic resins with different solvent solubility as sea parts (easily soluble polymers) and island parts (difficult-to-soluble polymers). By using solvents to dissolve and remove the sea parts, the island parts become micro-fine fibers, forming an island-type composite fiber. By using island-type composite fibers, when removing the sea parts, appropriate gaps can be created between the island parts, that is, between the ultra-fine fibers inside the fiber bundle, thus resulting in better hand feel and surface appearance quality from the perspective of artificial leather.

[0129] From the viewpoint of obtaining ultrafine fibers with a sea-island composite structure, the method of spinning ultrafine fibers with uniform single fiber fineness is preferably to use a sea-island composite spinneret and to use a polymer inter-arrangement body in which the sea part and the island part are arranged to be spun.

[0130] The method of making the island part contain pigment can be any of the following: using resin fragments in which pigment is mixed with the resin of the island part and spinning, or preparing a masterbatch in which pigment has been mixed with resin in advance, and then mixing the masterbatch with other resin fragments and spinning.

[0131] The marine system of the island-type composite fiber can be: a copolymer polyester by copolymerizing polyethylene, polypropylene, polystyrene, sodium isophthalate sulfonate or polyethylene glycol; and polylactic acid, etc. From the viewpoint of yarn production or easy solubility, polystyrene or copolymer polyester is preferred.

[0132] In the method for manufacturing artificial leather of the present invention, when using island-type composite fibers, it is preferable to use island-type composite fibers with an island strength of 2.5 cN / dtex or higher. By having an island strength of 2.5 cN / dtex or higher, more preferably 2.8 cN / dtex or higher, and even more preferably 3.0 cN / dtex or higher, the abrasion resistance of the artificial leather can be improved, and the decrease in frictional strength caused by fiber shedding can be suppressed.

[0133] In this invention, the island strength of the island-type composite fiber is calculated by the following method. (1) Bundle 10 island-type composite fibers with a length of 20cm. (2) After dissolving and removing the sea part from the sample in (1), air dry. (3) According to JIS L1013:2010 "Test Methods for Chemical Fibers", "8.5 Tensile Strength and Elongation" "8.5.1 Standard Time Test", 10 tests (N=10) are performed under the conditions of a holding length of 5cm, a tensile speed of 5cm / min, and a load of 2N. (4) The arithmetic mean (cN / dtex) of the test results obtained in (3) is rounded to two decimal places and set as the island strength of the island-type composite fiber.

[0134] <Steps for Manufacturing Fiber Complexes> Ultrafine fibers or island-type composite fibers can be manufactured using conventional fiber complex manufacturing methods for forming knitted / woven fabrics or nonwoven fabrics. Preferably, the spun ultrafine fibers are opened, then a fiber web is formed using methods such as cross-wrapping, and finally complexed to obtain a nonwoven fabric. Methods for complexing the fiber web to obtain a nonwoven fabric include: needle punching, water jet perforation, etc.

[0135] The form of the non-woven fabric is as described above. Both short fiber non-woven fabric and long fiber non-woven fabric can be used. If it is short fiber non-woven fabric, there are more fibers in the thickness direction of the artificial leather than in long fiber non-woven fabric. When napping is performed, the surface of the artificial leather can obtain a higher density.

[0136] When the nonwoven fabric is a short-fiber nonwoven fabric, it is preferable to perform a crimping process on the obtained ultrafine fiber phenotype fibers, cut them to a predetermined length to obtain raw cotton, and then perform fiber opening, lamination, and complexation to obtain the short-fiber nonwoven fabric. The crimping and cutting processes can be carried out using known methods.

[0137] Furthermore, when the artificial leather contains knitted / woven fabric (a), the obtained nonwoven fabric and knitted / woven fabric (a) are laminated and then bonded together. When bonding the nonwoven fabric and knitted / woven fabric (a), knitted / woven fabric (a) is layered on one or both sides of the nonwoven fabric, or knitted / woven fabric (a) is sandwiched between multiple nonwoven fabric webs, and then needle punching or water jet perforation is used to make the fibers of the nonwoven fabric and knitted / woven fabric (a) entangled with each other.

[0138] The nonwoven fabric composed of ultrafine fibers that have undergone needle-punching or water-jet perforation treatment preferably has an apparent density of 0.15 g / cm³ or higher and 0.45 g / cm³ or lower. By setting the apparent density to 0.15 g / cm³ or higher, the sheet material can obtain sufficient morphological and dimensional stability. On the other hand, by setting the apparent density to 0.45 g / cm³ or lower, sufficient space can be maintained for imparting polymer elastomers.

[0139] In order to improve the density of the fibers, the above-mentioned nonwoven fabrics also undergo heat shrinkage treatment using warm water or steam in the better state sample.

[0140] Next, the nonwoven fabric is impregnated with an aqueous solution of a water-soluble resin, and the water-soluble resin can also be applied by drying. By applying a water-soluble resin to the nonwoven fabric, the fibers are fixed and the dimensional stability is improved.

[0141] <Steps for expressing ultrafine fibers> In the case of using island-type composite fibers, the obtained fibrous substrate is treated with a solvent in this step to express ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less.

[0142] The microfiber processing system can be implemented by immersing a nonwoven fabric made of island-type composite fibers in a solvent, thereby removing the sea portion of the island-type composite fibers by dissolving them.

[0143] When the ultrafine fiber is a sea-island type composite fiber, as a solvent to dissolve and remove the sea portion, organic solvents such as toluene or trichloroethylene can be used when the sea portion is polyethylene, polypropylene, or polystyrene. Furthermore, when the sea portion is a copolymer polyester or polylactic acid, an alkaline aqueous solution such as sodium hydroxide can be used. Also, when the sea portion is a water-soluble thermoplastic polyvinyl alcohol resin, hot water can be used.

[0144] <Step of Assembling Polymer Elastomer> This step involves impregnating a fiber complex, primarily composed of ultrafine fibers or ultrafine fiber phenotype fibers, with a solution of polymer elastomer and then solidifying it, thereby imparting a polymer elastomer. The method for fixing the polymer elastomer to the fiber complex involves impregnating the fiber complex with a solution of polymer elastomer followed by wet or dry solidification; the appropriate method may be selected depending on the type of polymer elastomer used.

[0145] The solvent used when imparting polyurethane as a polymeric elastomer is preferably N,N'-dimethylformamide or dimethyl sulfoxide. Alternatively, an aqueous polyurethane dispersion in water, in which polyurethane is dispersed in an emulsion form, may be used.

[0146] In addition, the polymer elastomer can be applied to the fiber complex before the ultrafine fiber is generated from the ultrafine fiber phenotype fiber, or it can be applied after the ultrafine fiber phenotype fiber is generated from the ultrafine fiber phenotype fiber.

[0147] <Step of cutting and grinding the fiber complex containing polymer elastomer> From the point of view of manufacturing efficiency, the fiber complex formed by completing the above steps and imparting polymer elastomer is preferably cut in half in the thickness direction to form two fiber complex half sheets.

[0148] Furthermore, a napping treatment can be applied to the fiber complex formed by the above-mentioned polymer elastomer or the halved sheet to form a napped surface. The napping treatment can be performed by grinding with sandpaper or a roller sander. The napping treatment can be performed on only one side or on both sides.

[0149] When performing the napping process, a lubricant such as a polysiloxane emulsion can be applied to the surface of the fiber complex before the napping process is performed. Furthermore, by applying an antistatic agent before the napping process, the grinding powder generated during grinding is less likely to accumulate on the sandpaper. In this way, a napped sheet with a napped surface can be formed.

[0150] <Steps for dyeing napped sheets> It is preferable to perform a dyeing process on the aforementioned napped sheets. This dyeing process can be performed using, for example: liquid dyeing using a roll dyeing machine or a liquid dyeing machine; immersion dyeing using a continuous dyeing machine; or dyeing the napped surface using roller dyeing, screen dyeing, inkjet dyeing, sublimation dyeing, or vacuum sublimation dyeing. Among these, from the viewpoint of obtaining a soft hand feel and from the viewpoint of quality or appearance quality, a liquid dyeing machine is preferred. Furthermore, various resin finishing processes can be performed after dyeing as needed.

[0151] <Step of performing layering integration on knitted / woven fabric (b)> On the opposite side of the napped surface of the napped sheet (in the case where both sides have napped surfaces, this refers to the napped surface that becomes one of the product surfaces), it is preferable to perform layering integration on the knitted / woven fabric (b) using an adhesive. The adhesive can be applied using devices such as rotary screens, blade roller coaters, gravure roller coaters, contact roller coaters, and calender coaters, with a fixed amount applied. Among these, in order to give the artificial leather a good hand feel, it is preferable to use a rotary screen or a gravure roller coater to form a discontinuous adhesive layer. By forming a discontinuous adhesive layer, the hand feel of the artificial leather can be prevented from hardening or the breathability reduced. The aforementioned "discontinuous adhesive layer" refers to a horizontal surface of the knitted / woven fabric or napped sheet that is the bonding surface, where there are portions where the adhesive is present and portions where it is not present, for example, the adhesive is distributed in dots.

[0152] When using a thermoplastic resin as the adhesive, hot pressing can achieve a seamless bond. Hot pressing can be achieved using methods such as heated rollers. When using heated rollers, it is preferable to have the temperature of the heated roller on the knitted / woven fabric side higher than the temperature of the heated roller on the outer sheet side. When using a wet-curing resin as the adhesive, bonding is promoted under appropriate temperature and humidity conditions, commonly referred to as "curing".

[0153] When using heated rollers for heat bonding, the roller temperature on the knitted / woven fabric side is preferably 80~180℃, more preferably 100~160℃. If the roller temperature on the knitted / woven fabric side is below 80℃, the bonding process will take longer and the workload will increase. Furthermore, if the roller temperature on the knitted / woven fabric side is above 180℃, the artificial leather will feel rough and stiff.

[0154] <Step of applying a functional agent (flame retardant, etc.)> By applying a functional agent (flame retardant, etc.) to one surface of the above-mentioned pile sheet to form a functional surface (flame retardant surface), an artificial leather substrate can be obtained. Here, a functional agent (flame retardant, etc.) with a viscosity of 0.1 N / cm² or more and 2.0 N / cm² or less is applied to form a functional surface (flame retardant surface). Alternatively, the coefficient of kinetic friction (JIS K 7125) of this functional surface is 0.15 or more and 0.60 or less, and the stiffness of the artificial leather substrate is set to 30 mm or more and 150 mm or less. This step forms a functional surface (flame retardant surface, etc.) on the opposite surface of the pile surface (in the case where both sides have pile surfaces, this refers to the pile surface that becomes the product surface) of the pile sheet.

[0155] Methods for forming a functional surface (such as a flame-retardant surface) include, for example, applying the functional surface (such as a flame-retardant surface) to the aforementioned laminated sheet of piled fabric or knitted / woven fabric (b) using an apparatus such as a rotary screen, a blade roller coater, a gravure roller coater, a contact roller coater, or a calender coater. Although it is also possible to apply the functional agent (such as a flame retardant) and then transfer it to the surface by drying, the stability of the surface layer is poor. Alternatively, the above-mentioned piled treatment can be further performed after applying the functional agent (such as a flame retardant) and drying. Or, the functional agent (such as a flame retardant) can be applied to the knitted / woven fabric (b) in advance, and then the knitted / woven fabric (b) can be laminated on the opposite surface of the piled surface of the piled sheet (in the case where both sides have piled surfaces, it refers to the piled surface that becomes the product side) to form a functional surface (such as a flame-retardant surface).

[0156] After the functional agent (flame retardant, etc.) is applied, in order to penetrate into the interior, the application amount or penetration amount of the functional agent (flame retardant, etc.) is adjusted by means of adjusting the viscosity of the functional agent (flame retardant, etc.) or by using a screen such as a gravure roller. The drying method after applying the functional agent (flame retardant, etc.) can be carried out by using a known dryer such as a tenter dryer.

[0157] <Step of forming openings> Then, for the functional (flame retardant, etc.) sheet with the functional surface (flame retardant, etc.) already formed, a plurality of openings are provided on at least the functional surface (flame retardant, etc.). The means of providing the openings can be, for example, perforation or drilling, or laser processing. Openings can be formed not only on the functional surface (flame retardant, etc.) but also on the other side. The timing of the openings is not limited; for example, the lamination can be performed after openings are made in the fiber complex and the knitted / woven fabric (b) respectively. Preferably, a functional agent (flame retardant, etc.) is applied to the laminated sheet, and a through opening is formed using a drilling or perforating needle or perforating chisel. Artificial leather can be obtained by forming these openings.

[0158] Since the contact area of ​​the artificial leather after the opening is formed is smaller than that before the opening, the coefficient of dynamic friction of the functional surface is reduced. For example, from the viewpoint of stacking polyurethane foam on the functional surface using frame lamination or other methods, or from the viewpoint of the next step of processing, the coefficient of dynamic friction of the functional surface of the artificial leather with the opening is preferably 0.10 to 0.55.

[0159] <Post-processing steps> Furthermore, artificial leather can also be formed with designed features on its surface, as needed. Post-processing treatments such as embossing, laser processing, ultrasonic processing, and printing can be performed.

[0160] The artificial leather of the present invention, obtained according to the manufacturing method described above, has moderate breathability and a soft feel, and excellent functionality (flame retardancy, etc.). It possesses a touch and elegant appearance similar to natural suede, and therefore can be widely used in vehicle interior materials, decorative materials, building materials, and general merchandise. In particular, from the viewpoint of its excellent functionality (flame retardancy, etc.), it is suitable for use in vehicle interior materials. Furthermore, the artificial leather substrate of the present invention, obtained according to the manufacturing method described above, has excellent opening-forming properties, making it suitable for use in the manufacture of the aforementioned artificial leather. [Example]

[0161] Next, the artificial leather of the present invention will be described in more detail using examples; however, the present invention is not limited to these examples. Furthermore, unless otherwise stated, all physical properties were measured according to the methods described above.

[0162] [Measurement method and evaluation processing method] (1) Average single fiber diameter of ultrafine fiber (μm) The average single fiber diameter of ultrafine fiber was determined by observing with a scanning electron microscope of type "VW-9000" manufactured by KEYENCE Co., Ltd., and the average single fiber diameter was calculated.

[0163] (2) The abrasion resistance of artificial leather was determined according to the abrasion resistance test conducted in accordance with JIS L1096:2010 "Test Methods for Knitted and Woven Fabrics", specifically "8.19 Abrasion Strength and Color Change by Friction" and "8.19.5 E Method (Martindale Method)". The pressure was set to 12.0 kPa, and after 20,000 abrasion cycles, the abrasion condition of the artificial leather surface was observed and compared with the surface condition before the test. The degree of abnormality was judged according to the following levels. In this evaluation, levels 3 to 5 are considered "acceptable". • Level 5: Not detected at all. • Level 4: Slightly detected, but almost imperceptible. • Level 3: Obviously detected, but not noticeable. • Level 2: Slightly noticeable abnormality detected. • Level 1: Obvious abnormality detected.

[0164] (3) Tensile strength of artificial leather Two 2cm×20cm test pieces of artificial leather were taken in any direction and the tensile strength was measured in accordance with the provisions of "6.3.1 Tensile strength and elongation (ISO method)" of JIS L1913:2010 "General nonwoven fabrics test method". The average of the two pieces was taken as the tensile strength of the artificial leather.

[0165] (4) Appearance and Touch Quality of Artificial Leather The appearance and touch quality of artificial leather were evaluated by 20 judges, 10 healthy adult males and 10 adult females, based on visual value. The evaluation with the highest score was assigned as the appearance and touch quality of the artificial leather. In the case of a tie, the higher score was assigned as the appearance and touch quality of the artificial leather. The qualification grades of the present invention are "A, B, C". • A: It has an elegant appearance and dense surface touch like natural leather, presenting the highest quality. • B: Although not as good as natural leather, it has a slightly elegant appearance and slightly dense surface touch, presenting a medium quality. • C: It has an artificial elegance and surface touch, presenting a low quality. • D: It lacks elegance and has a rough surface touch, feeling like a cheap product.

[0166] (5) Evaluation of the air permeability of artificial leather For the artificial leather to be tested, one 200mm×200mm test piece was taken from each of five different locations. The air permeability was measured according to the "8.26 Air permeability" A method (Fraser method) of JIS L1096:2010 "Test methods for knitted and woven fabrics". The conversion table attached to the test apparatus was used to calculate the amount of air passing through the test piece (cm3 / cm2 / sec). Then, the average value of the five calculated values ​​was taken as the air permeability (cm3 / cm2 / sec).

[0167] (6) Softness test of artificial leather The softness of artificial leather was tested according to the cantilever method described in "8.21 Stiffness" of JIS L1096:2010 "Test Methods for Knitted and Braided Fabrics". A 2cm×15cm test piece was made and placed on a horizontal platform with a 45° incline. The test piece was allowed to slide and the scale reading when the center point of one end of the test piece contacted the incline was taken for evaluation.

[0168] (7) The flame retardancy test of artificial leather was conducted as described above, according to the US Federal Motor Vehicle Safety Standard (FMVSS), No. 302, for the combustion test specifications (horizontal burning speed) of automotive interior materials. The test piece size was 350mm × 100mm.

[0169] (8) Water stain test of artificial leather: Place the artificial leather sample, drip 3 cm3 of water onto the surface, and let it dry naturally. Observe the formation of ring stains or the like on the surface of the sample. If ring stains or the like are clearly visible to the naked eye, it is considered unqualified.

[0170] (9) Opening ratio of artificial leather The so-called "opening ratio" refers to the area ratio of the opening portion in the total area of ​​one side of artificial leather, which is called the area ratio in the aforementioned surface. For a 20cm×20cm artificial leather sample, the image was scanned and the area ratio was calculated from the binarization process. This operation was performed on samples from 5 locations, and the area ratio was then obtained from the arithmetic mean.

[0171] (10) The thickness direction of the flame retardant is relative to the cross section of the artificial leather. The cross section was observed using a scanning electron microscope (SEM) of the "VW-9000" type manufactured by KEYENCE Co., Ltd., and the thickness direction of the flame retardant was calculated according to the above method.

[0172] (11) Density of fiber complex containing polymer elastomer The density of the fiber complex containing polymer elastomer shown in the examples and comparative examples (density of artificial leather without knitted / woven fabric (b) and flame retardant) was, as mentioned above, determined by dividing the basis weight of the fiber complex (including knitted / woven fabric (a)) by the thickness of the fiber complex containing polymer elastomer according to "6.2 Mass per unit area (ISO method)" of JIS L1913:2010 "General nonwoven fabric test method". Five samples of fiber complex containing polymer elastomer were randomly selected, and the average value was set as the density.

[0173] Density (g / cm3) = Basis weight (g / m2) ÷ Thickness (mm) ÷ 1000.

[0174] (12) The viscosity of the functional agent is measured and calculated in the following order. (1) Heat the functional agent to 60°C. (2) Using a viscosity meter (Tack Taster TA-500 UBM Corporation), press a stainless steel probe (contact pressure 24.5 N / cm2) onto the functional agent (flame retardant, etc.) at a speed of 6 mm / min and hold for 5 seconds. (3) After (2), read the maximum load when tearing at 6 mm / min. (4) Repeat (2) to (3) 5 times, and round the arithmetic mean of the obtained values ​​to the third decimal place as the viscosity at 60°C.

[0175] (13) The coefficient of kinetic friction was determined by taking three 80mm×200mm test pieces from artificial leather and measuring them according to JIS K 7125 with a test speed of 100mm / min, a sliding piece of 63mm×63mm and a load of 1.92N. The average value was set as the coefficient of kinetic friction.

[0176] [Example 1] <Steps for manufacturing raw cotton> Polyethylene terephthalate was used as the island component, and polystyrene was used as the sea component. A sea-island type composite spinneret with 16 islands was used. Melt spinning was performed at an island / sea mass ratio of 80 / 20, an output rate of 1.2 g / (min·hole), and a spinning speed of 1100 m / min. The resulting yarn was then stretched 2.7 times in a spinning oil bath set to 90°C. After being wound using a press-fit winding machine, the yarn was cut to a length of 51 mm to obtain sea-island type composite fiber raw cotton with a single fiber fineness of 3.8 dtex.

[0177] <Steps for manufacturing fiber complexes> First, using the raw cotton obtained as described above, a laminated web is formed through carding and web forming steps. Then, needle-punching is performed using a punch with a count of 2500 / cm2 to obtain a nonwoven fabric with a basis weight of 540g / m2 and a thickness of 2.4mm.

[0178] <Steps for Derivation of Ultrafine Fibers> The nonwoven fabric obtained as described above is shrunk using hot water at 96°C. Then, a polyvinyl alcohol (hereinafter referred to as "PVA") aqueous solution with a concentration of 12% by mass and a saponification degree of 88% is impregnated in the nonwoven fabric shrunk by hot water. The fabric is then extruded using rollers and dried using hot air at 120°C while transferring the PVA for 10 minutes, resulting in a PVA sheet with a PVA content of 25% by mass relative to the sheet matrix. The PVA sheet obtained in this manner is then immersed in trichloroethylene and subjected to extrusion and compression 10 times using pressure rollers. This process removes the PVA by dissolution and compresses the PVA sheet, resulting in a PVA sheet formed by complexing ultrafine fiber bundles with PVA. The average single fiber diameter of the ultrafine fibers is 4.4 μm.

[0179] <Step of imparting polymeric elastomer> The PVA sheet obtained as described above is impregnated in a dimethylformamide (DMF) solution of polyurethane, with polyurethane as the main component and adjusted to a solid content concentration of 13%. Then, the PVA sheet impregnated in the polyurethane DMF solution and descaled is extruded using rollers. Next, the sheet is impregnated in a 30% by mass DMF aqueous solution to solidify the polyurethane. Then, the PVA and DMF are removed using hot water, and a polysiloxane oil emulsion adjusted to a concentration of 1% by mass is impregnated. The amount of polysiloxane lubricant is 0.5% by mass relative to the total mass of the fiber complex and the polyurethane, and the mixture is dried using hot air at 110°C for 10 minutes. This resulted in a polyurethane sheet with a thickness of 1.8 mm and a polyurethane mass percentage relative to the fiber complex mass of 33%. The density of the polyurethane sheet, which is a fiber complex containing a polymeric elastomer, is 0.35 g / cm³.

[0180] <Steps for cutting in half and napping> The polyurethane sheet obtained as described above is cut in half to a thickness of 1 / 2. Next, using ring sandpaper of grit 180, the surface of the cut half is ground down to 0.3 mm to perform a napping treatment, resulting in a napped sheet with a thickness of 0.6 mm.

[0181] <Dyeing and Finishing Steps> The piled sheet obtained above is dyed with black disperse dye at 120°C using a liquid dyeing machine, followed by reduction washing. Then, it is dried at 100°C for 7 minutes to obtain a dyed sheet with an average single fiber diameter of 4.4μm, a basis weight of 220g / m2, and a thickness of 0.70mm.

[0182] <Flame-retardant processing> 20 parts by weight of ammonium polyphosphate (manufactured by Wellchem, phosphorus content 28%, nitrogen content 14%) treated with silica-based resin as the main flame-retardant component, 0.2 parts by weight of polyoxyethylene sorbitan monostearate as a surfactant (non-ionic surfactant), 11 parts of methyl acrylate resin with 50% non-volatile components as a binder resin, and 4 parts by weight of melamine cyanurate (nitrogen content 49.4%) are mixed, and hydroxyethyl cellulose is used as a tackifier to obtain flame retardant A. A flame retardant processing agent solution containing 70% by mass of flame retardant A (adjusted to a viscosity of 3000 mPa·s using the aforementioned thickener) was applied to the surface opposite to the product surface of the dyed sheet using a screen coating machine. Then, it was dried at 100°C for 7 minutes to obtain a flame retardant sheet with an adhesion amount of 20% by mass relative to the mass of the dried artificial leather.

[0183] <Perforation Processing> Artificial leather (needle diameter: 1.2 mm, longitudinal spacing: 5 mm, transverse spacing: 5 mm, opening rate: 6%) was obtained by perforating the above-mentioned sheet with flame retardant using a perforated plate with implanted needles. The perforated openings were not clogged with fiber debris, and the edges of the openings were free of flame retardant residue, resulting in a neat opening. After air-blowing away the debris, no fiber debris or flame retardant residue remained on the perforated plate. The obtained artificial leather exhibits moderate breathability and a soft feel, excellent flame retardancy, and a dense texture and elegant appearance similar to natural suede. The viscosity of the flame retardant was 0.45 N / cm² at 60°C, 0.20 N / cm² at 40°C, and 0.14 N / cm² at 20°C. The basis weight of the artificial leather was 240 g / m², and the thickness was 0.72 mm. The results are shown in Table 1.

[0184] [Example 2] Except for the ultrafine fiber exhibiting a composite structure of island and sea components, which is a composite spinneret with 16 islands, and is melt-spun at an island / sea mass ratio of 55 / 45, a feed rate of 1.0 g / (min·hole), and a spinning speed of 1100 m / min, the artificial leather was obtained in the same manner as in Example 1, except that the extension ratio was set to 3.4 times in a spinning oil bath at a set temperature of 90°C. The density of the polyurethane sheet was 0.360 g / cm3, which was higher than that of Example 1, the amount of flame retardant infiltrated was less, and W / W0 = 0.07. The average single fiber diameter of the ultrafine fiber was 2.9 μm. The results are shown in Table 1.

[0185] [Example 3] Using the raw cotton described in Example 1, after forming a laminated network through a carding machine and a cross-wrap step, a complex strand (average single fiber diameter: 11 μm, total fiber: 84 dtex, 72 raw yarns) A 2500T / m stranded yarn is applied to both weft and warp yarns and a plain fabric with a weaving density of 95 strands / 2.54cm and 76 strands / 2.54cm latitude (base weight 75g / m2) is laminated above and below the above laminated web. Then, except for needle rolling treatment using a punch count of 2500 counts / cm2 to obtain a fiber complex nonwoven fabric with a base weight of 700 g / m2 and a thickness of 3.0 mm, an average single fiber diameter of 4.4 μm, a base weight of 360 g / m2, and a thickness of 1.0 mm were obtained in the same manner as in Example 1. becomes a tough artificial leather with higher strength than in Example 1. The results are shown in Table 1 .

[0186] [Example 4] The complex yarn made of polyethylene terephthalate (total fiber: 48 dtex, 18 raw yarn) was made into warp fabric fabric using a single-sided warp knitting machine, dyed using a black disperse dye, and the preparation density was warp 32 strands / 2.54cm, latitude 48 strands / The dyeing of 2.54cm was woven fabric, then the low melting point nylon resin (softening temperature 90°C) of the adhesive was applied 20g / m2 in a dot matrix using a gravure roller coater, and dried using hot air at a temperature of 100°C to obtain the adhesive through the braid. A composite sheet with a base weight of 440 g / m2 and a thickness of 1.1 mm was obtained using a heating roller that was heated to a temperature of 150°C on the side of the warp braid and hot pressed to the dyed sheet of Example 3. An artificial leather with a base weight of 490 g / m2 and a thickness of 1.2 mm was obtained by performing flame-retardant processing, perforation processing in the same manner as in Example 3 for the composite sheet. A higher strength artificial leather is obtained than in Example 3. By attaching a refractory agent to the warp braid as a whole, so that the warp braid of a single component forms a high flame retardancy, artificial leather can present a high flame retardancy result. The results are shown in Table 1 .

[0187] [Example 5] Using a multifilament composed of polyethylene terephthalate (PET) as the island component and polystyrene as the sea component (84 dtex / 25 f, average single fiber diameter of the ultrafine fibers after desea removal: 9 μm), and a cross-processed yarn containing PET multifilament (33 dtex / 12 f), a circular knitted base fabric was formed using a wrinkled structure. Except for forming the circular knitted base fabric from the fiber complex, the artificial leather containing the fiber complex containing a polymer elastomer was obtained in the same manner as in Example 1. The basis weight of the artificial leather was 240 g / m², and the thickness was 0.72 mm. Compared to Example 1, the artificial leather exhibited a lower-grade texture and a stiffer feel, but showed excellent watermark and perforation processing properties. The results are shown in Table 1.

[0188] [Example 6] Except that the flame retardant was prepared by setting 30 parts by mass of dialkylphosphine metal salt as the main component of the flame retardant and 15 parts by mass of acrylate copolymer as the binder resin, and forming a flame retardant processing agent solution containing 50% by mass of flame retardant B, the rest were prepared in the same manner as in Example 4 to obtain artificial leather with a basis weight of 490 g / m2 and a thickness of 1.2 mm. The viscosity of the flame retardant was 1.50 N / cm2 at 60°C, 0.50 N / cm2 at 40°C, and 0.30 N / cm2 at 20°C. The viscosity of the flame retardant was higher at room temperature, and the amount penetrated was less than in Example 4. Due to the higher viscosity at 60°C, some holes or punching pins were blocked after perforation, but artificial leather with excellent flame retardancy and appearance quality could still be obtained. The results are shown in Table 1.

[0189] [Example 7] Except that the opening ratio was set to 14%, artificial leather was obtained in the same manner as in Example 4. Since there were more openings than in Example 4, the flame retardancy was slightly worse, but artificial leather with excellent softness and other properties was still obtained. The results are shown in Table 1.

[0190] [Comparative Example 1] Except that the flame retardant was composed of 5 parts by weight of methyl acrylate resin and 10 parts by weight of acrylonitrile resin in the adhesive components, the artificial leather was obtained in the same manner as in Example 4. It exhibited high viscosity, blockage of openings during perforation, and poor air permeability. The results are shown in Table 1.

[0191] [Comparative Example 2] Except that the average single fiber diameter of the ultrafine fibers was set to 11 μm, the artificial leather was obtained in the same manner as in Example 4. The appearance quality exhibited a rough surface texture without elegance. The results are shown in Table 1.

[0192] [Table 1] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Fiber complex Average single fiber diameter (μm) of ultrafine fibers 4.4 2.9 4.4 4.4 9.0 4.4 4.4 4.4 11.0 Fiber complex non-woven fabric non-woven fabric non-woven fabric non-woven fabric woven fabrics non-woven fabric non-woven fabric non-woven fabric non-woven fabric Knitted / woven fabrics (a) - - Knitted fabrics Knitted fabrics - Knitted fabrics Knitted fabrics Knitted fabrics Knitted fabrics Knitted / woven fabrics (b) - - - warp-knitted fabrics - warp-knitted fabrics warp-knitted fabrics warp-knitted fabrics warp-knitted fabrics polymer elastomers Polyurethane Density of fiber complex containing polymeric elastomers (g / cm³) 3 ) 0.35 0.36 0.40 0.40 0.30 0.40 0.40 0.40 0.42 Flame retardant Flame-retardant main components Ammonium polyphosphate Dialkylphosphine metal salts Ammonium polyphosphate Main resin Methyl acrylate acrylate Methyl acrylate Acrylonitrile Methyl acrylate Viscosity at 60℃ (N / cm) 2 ) 0.45 0.45 0.45 0.45 0.45 1.5 0.45 2.1 0.45 Artificial leather substrate (Before speaking) coefficient of kinetic friction 0.29 0.28 0.31 0.27 0.29 0.41 0.25 0.61 0.31 Stiffness (mm) 70 75 80 95 90 90 90 105 125 artificial leather Thickness (mm) 0.72 0.72 1.0 1.2 0.72 1.2 1.2 1.2 0.72 Basis weight (g / m 2 ) 240 240 360 360 240 360 330 360 362 W / W0 0.10 0.07 0.15 0.21 0.31 0.17 0.21 0.25 0.28 Opening ratio (%) 6 6 6 6 6 6 14 6 6 Ventilation (cm) 3 / cm 2 / sec) 110 105 100 90 110 95 140 65 95 Flame retardancy (mm / min) 25 30 20 10 40 Self-extinguishing 60 30 7 Tensile strength (N / cm) 50 55 70 80 40 78 70 75 82 Appearance quality and feel A A A A C A A A D abrasion resistance 5 4 5 5 3 5 4 5 5 Stiffness (mm) 65 70 75 90 85 85 85 100 120 Watermarks qualified qualified qualified qualified qualified qualified qualified qualified qualified Drilling processability good good good good good Slightly good good bad good

[0193] The present invention is described in detail using a specific form. However, various changes and modifications can be made without departing from the spirit and scope of the present invention, which can be easily conceived by those skilled in the art.

Claims

1. An artificial leather comprising: a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastomer, wherein one surface has a napped surface and the other surface has a flame-retardant surface with a flame retardant, and satisfying the following requirements 1 and 2: Requirement 1: At least a plurality of openings are provided on the flame-retardant surface; the pore size of the openings is 0.1 to 3.0 mm; the opening ratio of the flame-retardant surface is 1% or more and 40% or less; Requirement 2: the viscosity of the flame retardant is 0.1 N / cm² or more and 2.0 N / cm² or less; the amount of the flame retardant attached is 2 to 30% by mass relative to the artificial leather.

2. The artificial leather as claimed in claim 1, wherein, The aforementioned artificial leather has a plurality of openings on the napped surface and the flame-retardant surface, and at least one part of the openings is a through opening that extends from the napped surface to the flame-retardant surface.

3. The artificial leather as claimed in claim 1, wherein, The fiber complex system described above contains the fiber complex formed by the extremely fine fibers described above and is integrated with the knitted / woven fabric (a).

4. The artificial leather as claimed in claim 1, wherein, The aforementioned flame-retardant surface is made of layers of knitted / woven fabric (b).

5. The artificial leather as claimed in claim 1, wherein, The thickness-direction presence ratio of the aforementioned flame retardant satisfies the following formula: 0.001≦W / W0≦0.7 where, W series refers to the thickness (mm) of the flame-retardant surface where the flame retardant exists; W0 series refers to the overall thickness (mm) of the artificial leather.

6. The artificial leather as claimed in claim 1, wherein, The aforementioned flame retardants contain phosphorus compounds.

7. The artificial leather as claimed in claim 1, wherein, The density of the fiber complex containing the above-mentioned polymeric elastomer is above 0.20 g / cm3 and below 0.50 g / cm3.

8. A method for manufacturing artificial leather according to any one of claims 1 to 7, comprising coating a flame retardant having a viscosity of 0.1 N / cm² to 2.0 N / cm² onto one surface of a pile sheet composed of a fiber complex containing extremely fine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, to form a flame retardant surface, and having at least a plurality of openings on the flame retardant surface.