Pile artificial leather

Abstract

The present invention uses a flocked artificial leather, which comprises a non-woven fabric as an aggregate of ultrafine fibers and a polymer elastomer imparted to the non-woven fabric, and has a flocked surface formed by flocking the ultrafine fibers on at least one surface. The fineness of the ultrafine fibers is 0.5 dtex or less, and the tensile strength is 6 to 9 mN. A plurality of ultrafine fibers form a fiber bundle. In a region other than the fiber surface layer portion, the ultrafine fibers forming the fiber bundle are not restricted by the polymer elastomer. The content ratio of the polymer elastomer is 16 to 40%, and the apparent density of the flocked artificial leather is 0.38 g / cm<supgt;3< / supgt; or more.

Description

Technical Field

[0001] The present invention relates to a napped artificial leather which can be preferably used as a surface material of clothing, shoes, furniture, car seats, sundry goods, and the like. Background Art

[0002] Currently, napped artificial leathers such as suede-like artificial leather and nubuck-like artificial leather are known. The napped artificial leather has a napped surface, and the napped surface includes napped fibers formed by napping one side of a nonwoven fabric impregnated with a polymer elastic body. Such napped artificial leathers are required to have wear resistance.

[0003] Regarding the wear resistance of raised nap artificial leather, for example, the following patent document 1 discloses a suede-like artificial leather, which is obtained by extracting a component of the mixed fiber after imparting the polymer elastomer to a leather-like sheet formed by ultrafine fibers and a polymer elastomer, and then imparting the polymer elastomer again, thereby restricting the ultrafine fibers that form a fiber bundle with the polymer elastomer.

[0004] In addition, the following patent document 2 discloses a soft and wear-resistant artificial leather, which is obtained by applying a treatment liquid containing inorganic salts dissolved and mixed in an aqueous polyurethane emulsion with an average particle size of 0.1 to 2.0 μm to a non-woven sheet containing a fiber layer formed by ultrafine fibers with a single fiber fineness of less than 0.5 denier as a surface fiber layer, and heating and drying the treated liquid.

[0005] Patent Document 3 listed below discloses an artificial leather obtained by preparing an artificial leather base, swelling a polymer elastic body, and then bonding ultrafine fibers and the polymer elastic body by compression.

[0006] In addition, the following patent document 4 discloses a napped artificial leather comprising a nonwoven fabric formed by entangled fibers and a polymer elastomer, wherein the 100% modulus (A) of the polymer elastomer and the content ratio (B) of the polymer elastomer satisfy the relationship B≥-1.8A+40, A>0.

[0007] In addition, the following patent document 5 discloses a sheet-like article, which uses artificial leather comprising a non-woven fabric mainly composed of ultrafine fibers and an elastic polymer, wherein the non-woven fabric is composed of a non-woven fabric containing ultrafine long fibers, the ultrafine long fibers contain polyester as a main component, the polyester contains 1 to 500 ppm of a component derived from 1,2-propylene glycol, and the CV value of the unit area weight in the width direction of the sheet-like article is less than 5%.

[0008] In addition, the napped artificial leather also has the following problems: the napped surface is rubbed, causing the ultrafine fibers to be unthreaded or broken, or the ultrafine fibers free on the surface are further rubbed and entangled, causing pilling, which is a phenomenon in which small spherical lumps such as hair balls are generated.

[0009] As methods for suppressing pilling of napped artificial leather, there are known methods of increasing the degree of cohesion of the ultrafine fibers forming the nonwoven fabric, or increasing the content of the polymer elastic body impregnated into the nonwoven fabric or foaming the polymer elastic body to restrict the ultrafine fibers; or weakening the strength of the ultrafine fibers to make them easy to break. However, there are the following problems: when the content of the polymer elastic body impregnated into the nonwoven fabric is increased to strengthen the restriction of the ultrafine fibers, the hand feel will become harder, and when the actual volume is increased by foaming the polymer elastic body to strengthen the restriction force, the manufacturing cost will increase. In addition, if the strength of the ultrafine fibers is weakened to make them easy to break, pilling will become less likely to occur, but on the other hand, there is a problem of reduced wear resistance.

[0010] Regarding a napped artificial leather having excellent pilling resistance, the following Patent Document 6 discloses a napped artificial leather having improved cohesion of ultrafine fibers, and the napped surface is subjected to a surface peeling treatment before and after which the napped surface is peeled off, and the napped surface is measured by a spectrophotometer based on L * a * b * L of the color system * The rate of change in value is less than +9%.

[0011] As a technique for improving the wear resistance of napped artificial leather, for example, Patent Document 7 below discloses a napped artificial leather in which a polymer elastomer obtained from a water dispersion of the polymer elastomer is present at the root of the naps and in the vicinity thereof.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Laid-Open No. 51-75178

[0015] Patent Document 2: Japanese Patent Application Laid-Open No. 06-316877

[0016] Patent Document 3: Japanese Patent Application Publication No. 2001-81677

[0017] Patent Document 4: WO2019 / 058924 Pamphlet

[0018] Patent Document 5: Japanese Patent Application Publication No. 2019-26996

[0019] Patent Document 6: Japanese Patent Application Publication No. 2017-106127

[0020] Patent Document 7: Japanese Patent Application Publication No. 2011-74541 Summary of the invention

[0021] Problems to be solved by the invention

[0022] The suede-like artificial leather disclosed in Patent Document 1 has improved wear resistance, but has a problem of hard hand feeling due to the restriction of ultrafine fibers by the polymer elastic body. In addition, the artificial leather disclosed in Patent Document 2 also has a problem of hard hand feeling despite improved wear resistance. In addition, the artificial leather disclosed in Patent Document 3 also has a problem of hard hand feeling when trying to fully improve wear resistance due to the restriction of ultrafine fibers by the polymer elastic body. In addition, the artificial leather disclosed in Patent Document 4 has improved wear resistance, but has a problem of not being able to fully improve resistance to friction and discoloration due to the fall of ultrafine fibers. In addition, the artificial leather disclosed in Patent Document 5 also has a problem of hard hand feeling due to the restriction of ultrafine fibers by the polymer elastic body, although the wear resistance is improved.

[0023] In addition, the napped artificial leather disclosed in Patent Document 6, which has an improved degree of cohesion of ultrafine fibers, has an improved pilling resistance, but has a problem of a hard feel. In addition, the napped artificial leather disclosed in Patent Document 7 also has an excellent abrasion resistance, but has a problem of a hard feel because the ultrafine fibers are restrained by the polymer elastic body.

[0024] An object of the present invention is to provide a napped artificial leather having a beautiful napped appearance, high abrasion resistance, high resistance to rubbing and discoloration, and a soft touch.

[0025] Solutions to the problem

[0026] One embodiment of the present invention relates to a napped artificial leather, comprising a nonwoven fabric as an entangled body of ultrafine fibers and a polymer elastic body imparted to the nonwoven fabric, and having a napped surface on at least one side in which the ultrafine fibers are napped, the fineness of the ultrafine fibers is 0.5 dtex or less, and the tensile strength is 6 to 9 mN, a plurality of ultrafine fibers form a fiber bundle, and in an area other than a fiber surface layer, the ultrafine fibers forming the fiber bundle are not restricted by the polymer elastic body, the content ratio of the polymer elastic body is 16 to 40% by mass, and the apparent density of the napped artificial leather is 0.38 g / cm 3As described above, based on such raised artificial leather, raised artificial leather with a beautiful raised appearance, high abrasion resistance, high friction and discoloration resistance, and a soft hand feeling can be obtained. It should be noted that the ultrafine fibers not being restricted by the polymer elastomer means that the ultrafine fibers forming the non-woven fabric form a fiber bundle formed by removing the sea component from the sea-island composite fiber, and within the ultrafine fiber bundle formed by removing the sea component from the sea-island composite fiber, the fibers are not adhered to each other by the polymer elastomer. It should be noted that in the case where the fibers in the ultrafine fiber bundle are not adhered to each other by the polymer elastomer, even if the polymer elastomer adheres to a part of the outer periphery of the ultrafine fiber bundle, the ultrafine fibers are not restricted by the polymer elastomer.

[0027] In addition, it is preferable that the tensile strength of the ultrafine fiber is the tensile strength A (mN) in the range of 6.5 to 8 mN, and the apparent density of the raised artificial leather is 0.38 to 0.48 g / cm 3 , and the content ratio B of the polymer elastomer satisfies 3.125×A ≤ B. Based on such raised artificial leather, raised artificial leather with further high pilling resistance can be obtained.

[0028] In addition, from the viewpoint of easily obtaining a raised artificial leather with a soft hand feeling by appropriately separating the polymer elastomer from the ultrafine fibers even when the amount of the polymer elastomer is increased, it is preferable that the polymer elastomer is a solvent-based polyurethane.

[0029] In addition, the foaming ratio of the polymer elastomer is preferably 0 to 5% by mass. In the case where the polymer elastomer is foamed at a high magnification, the volume of the polymer elastomer increases and surrounds the ultrafine fibers. As a result, the ultrafine fibers are less likely to shed, and the pilling resistance is improved. However, in order to foam the polymer elastomer at a high magnification, it is necessary to adjust the additives or increase the coagulation temperature. Therefore, from the viewpoint of an increased manufacturing cost tendency, it is not preferable.

[0030] In addition, from the viewpoint of the fibers after raising on the raised surface being less likely to shed and the fibers after raising being less likely to stand up due to friction, thereby improving the appearance grade, it is preferable that a part of the polymer elastomer present in the surface layer portion adheres to the vicinity of the root of the ultrafine fibers after raising.

[0031] In addition, from the viewpoint of easily obtaining the raised artificial leather as described above, it is preferable that the ultrafine fibers are formed by dissolving and removing the sea component from the sea-island composite fiber with an organic solvent.

[0032] In addition, from the viewpoint of easily obtaining the raised artificial leather as described above, it is preferable that the non-woven fabric is a spunbond non-woven fabric containing ultrafine fibers of long fibers.

[0033] Effects of the Invention

[0034] According to the present invention, a flocked artificial leather having a beautiful flocked appearance, high abrasion resistance, high friction and discoloration resistance, and a soft hand feeling can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is an explanatory diagram for explaining a method for measuring the tensile strength of ultrafine fibers.

[0036] Figure 2 A graph showing the plot of the content ratio (B) of the polymer elastomer with respect to the tensile strength (A) of the ultrafine fibers contained in the flocked artificial leather obtained in Examples 7 to 20.

[0037] Figure 3 A graph showing the plot of the content ratio (B) of the polymer elastomer with respect to the tensile strength (A) of the ultrafine fibers contained in the flocked artificial leather obtained in Examples 21 to 33 and Comparative Examples 8 to 11. DETAILED DESCRIPTION OF THE INVENTION

[0038] The flocked artificial leather of the present embodiment includes a non-woven fabric as an aggregate of ultrafine fibers and a polymer elastomer imparted to the non-woven fabric, and has a flocked surface formed by raising ultrafine fibers on at least one surface. The fineness of the ultrafine fibers is 0.5 dtex or less, and the tensile strength is 6 to 9 mN. A plurality of ultrafine fibers form a fiber bundle. In a region other than the fiber surface layer portion, the ultrafine fibers forming the fiber bundle are not restricted by the polymer elastomer. The content ratio of the polymer elastomer is 16 to 40% by mass, and the apparent density is 0.38 g / cm 3 The above. Hereinafter, for the flocked artificial leather of the present embodiment, while explaining an example of its manufacturing method, it will be described in detail.

[0039] The non-woven fabric as an aggregate of ultrafine fibers is a non-woven fabric of a fiber bundle of ultrafine fibers in which a plurality of ultrafine fibers form a fiber bundle. Such a non-woven fabric is obtained by subjecting sea-island type (matrix-microregion type) composite fibers to an aggregation treatment and then to an ultrafine fiberization treatment.

[0040] As a method for manufacturing the aggregate of ultrafine fibers, that is, the non-woven fabric, the following method can be cited: The sea-island type composite fibers are melt-spun to produce a web, the web is subjected to an aggregation treatment, and then the sea component is selectively removed from the sea-island type composite fibers to form ultrafine fibers. In addition, the sea-island type composite fibers can be densified by performing a fiber shrinkage treatment such as a heat shrinkage treatment using steam, hot water, or dry heat in any process before removing the sea component of the sea-island type composite fibers to form ultrafine fibers.

[0041] As a method for manufacturing a nonwoven fabric, there can be mentioned a method of forming a nonwoven fabric of long fibers by collecting, without cutting, sea-island type conjugate fibers spun by the spunbond method onto a nonwoven fabric. Further, as another method, the sea-island type conjugate fibers after melt spinning can be crimped and cut, and the raw cotton of the short fibers of the obtained sea-island type conjugate fibers can be carded to form a nonwoven fabric of short fibers. Among them, from the viewpoints of easy adjustment of the bonding state and high bulkiness, a nonwoven fabric of long fibers from sea-island type conjugate fibers spun by the spunbond method is particularly preferably used. Further, in order to impart morphological stability to the formed nonwoven fabric, a melt bonding treatment can also be carried out. Hereinafter, an example of using long fibers of sea-island type conjugate fibers will be described in detail as a representative example.

[0042] It should be noted that long fibers do not refer to short fibers intentionally cut after spinning, but continuous fibers. More specifically, for example, they are not filaments or continuous fibers intentionally cut into short fibers with a fiber length of about 3 to 80 mm. In order to form long fibers, the fiber length of the sea-island type conjugate fibers before ultrafine fibrillation is preferably 100 mm or more, and it is technically possible to manufacture, and as long as it is not inevitably cut during the manufacturing process, the fiber length can also reach several meters, several hundred meters, several kilometers or longer. It should be noted that due to needling during bonding and surface polishing, sometimes a part of the long fibers is inevitably cut during the manufacturing process to form short fibers.

[0043] Examples of the type of resin for the island component that becomes ultrafine fibers include: modified poly(ethylene terephthalate) (PET) such as poly(ethylene terephthalate), isophthalic acid-modified PET, sulfonic acid group isophthalic acid-modified PET, cationic dye-dyeable PET, etc.; aromatic polyesters such as poly(butylene terephthalate), poly(hexylene terephthalate); aliphatic polyesters such as polylactic acid, poly(ethylene succinate), poly(butylene succinate), poly(butylene succinate adipate), poly(hydroxybutyrate-hydroxyvalerate) resin; nylons such as nylon 6, nylon 66, nylon 10, nylon 11, nylon 12, nylon 6-12; polyolefins such as polypropylene, polyethylene, polybutene, poly(methylpentene), chlorinated polyolefin, etc. of fibers. It should be noted that modified PET is obtained by substituting at least a part of the ester-forming dicarboxylic acid monomer units or diol monomer units of unmodified PET with substitutable monomer units. Specific examples of the modified monomer units substituting the dicarboxylic acid monomer units include, for example, units from isophthalic acid, sodium isophthalate sulfonate, sodium naphthalene dicarboxylate sulfonate, adipic acid, etc. substituting the terephthalic acid unit. In addition, specific examples of the modified monomer units substituting the diol monomer units include, for example, units from diols such as butanediol, hexanediol, etc. substituting the ethylene glycol unit.

[0044] In addition, in the sea-island type composite fiber, dark pigments such as carbon black, white pigments such as zinc white, lead white, lithopone, titanium dioxide, precipitated barium sulfate and barite powder, weathering agents, mildew-proof agents, hydrolysis-proof agents, lubricants, fine particles, friction resistance adjusters, etc. can be incorporated as needed within the range that does not impair the effects of the present invention.

[0045] In order to form a non-woven fabric of a fiber bundle containing ultrafine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN, the following methods can be exemplified. The following methods can be cited: As the island component of the sea-island type composite fiber for manufacturing ultrafine fibers, a thermoplastic resin with a relatively high intrinsic viscosity and melting point is selected, and as the sea component, a thermoplastic resin that solidifies more slowly than the island component is selected, and a melt spinning is performed by applying a spinning draft (ejection speed / spinning speed) of a certain level or more to the island component.

[0046] Regarding the intrinsic viscosity of the resin of the island component for obtaining ultrafine fibers, from the viewpoint of easily forming ultrafine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN, it is preferably 0.55 to 0.8 dl / g, and more preferably about 0.55 to 0.75 dl / g. When the intrinsic viscosity of the thermoplastic resin that becomes the island component is too low, there is a tendency for the tensile strength of the obtained ultrafine fibers to decrease. In addition, when the intrinsic viscosity of the thermoplastic resin that becomes the island component is too high, melt spinning becomes difficult, and it is difficult to obtain ultrafine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN.

[0047] In addition, as the resin of the sea component that is subsequently extracted and removed or decomposed and removed, a resin with different solubility or decomposability from the resin of the island component and low compatibility can be used. Such a resin can be appropriately selected according to the type of the resin of the island component and the manufacturing method. Specifically, for example, olefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, resins such as polystyrene, styrene-acrylic copolymer, styrene-ethylene copolymer that are soluble in organic solvents and can be dissolved and removed by organic solvents, water-soluble resins such as water-soluble polyvinyl alcohol can be cited. Among them, from the viewpoint of enabling melt spinning even for resins of the island component with a high intrinsic viscosity, a resin that can be dissolved and removed by organic solvents is preferred, and polyethylene is particularly preferred.

[0048] The web of the sea-island type composite fiber can be manufactured by the spunbond method, and the spunbond method is as follows: Using a composite spinning nozzle in which a plurality of spinnerets are arranged in a given pattern, the molten stock of the sea-island type composite fiber is continuously ejected from the spinning orifice of the composite spinning nozzle at a given ejection speed, cooled while using a high-speed air flow, and stretched while being stacked on a conveyor belt-like movable net. In order to impart morphological stability to the net stacked on the net, thermocompression can be performed.

[0049] The number of island components that become ultrafine fibers in the cross-section of the sea-island composite fiber is preferably 5 to 200, more preferably 10 to 50, and particularly preferably 10 to 30, from the viewpoint of easily forming a fiber bundle of ultrafine fibers having appropriate voids.

[0050] At this time, as the melt spinning conditions of the sea-island composite fiber, the following conditions are preferred. From the viewpoint of easily obtaining ultrafine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN, when the ejection speed of the molten resin ejected from one hole of the spinning nozzle is set to A (g / min), the molten specific gravity of the resin is set to B (g / cm 3 ), the area of one hole is set to C (mm 2 ), and the spinning speed is set to D (m / min), the conditions set so that the spinning draft calculated by the following formula is in the range of 200 to 500, and further 250 to 400, are preferred.

[0051] ·Spinning draft = D / (A / B / C)

[0052] As the crimping treatment method, the following methods can be cited. For example, after laminating multiple layers of the long fiber web in the thickness direction using a cloth laminating device or the like, needling and high-pressure water jet treatment are performed under the condition that at least one or more hooks penetrate from both sides simultaneously or alternately. In addition, as the needling density of the needling treatment, from the viewpoint of easily obtaining high abrasion resistance, it is preferably 1500 to 5500 needles / cm 2 , more preferably 2000 to 5000 needles / cm 2 or so. When the needling density is too low, there is a tendency for the abrasion resistance to decrease, and when the needling density is too high, there is a tendency for the fibers to be cut off and the crimping degree to decrease.

[0053] In addition, at any stage from the spinning process of the sea-island composite fiber to the crimping treatment, an oil agent and an antistatic agent can be applied to the web. In addition, a shrinkage treatment of immersing the web in warm water at about 70 to 150 °C can be performed as needed to pre-densify the crimped state of the web.

[0054] As the unit area weight of the crimped web formed by crimping the web, it is preferably 100 to 2000 g / m 2in the range of about. In addition, a treatment of further increasing the fiber density and the degree of entanglement can be carried out by heat-shrinking the entanglement net as needed. Further, in order to further densify the entanglement net densified by the heat-shrinking treatment, fix the shape of the entanglement net, smooth the surface, etc., a treatment can be carried out by a hot roll with a surface temperature set to 100 to 150 °C as needed, or the entanglement net heated to above the softening point of the resin constituting the fiber can be pressed by a cooling roll with a surface temperature set below the softening point, thereby further increasing the fiber density. In particular, when pressing with a cooling roll with a surface temperature set 30 °C or lower lower than the softening point, the surface becomes smoother, so it is particularly preferred.

[0055] In the production of pile artificial leather, in order to impart shape stability and a substantial feeling, a polymer elastomer is impregnated and imparted to an entanglement net formed by entangling sea-island type composite fibers before removing the sea component. In this way, by impregnating and imparting a polymer elastomer to an entanglement net formed by entangling sea-island type composite fibers before removing the sea component, voids formed by removing the sea component can be formed between the ultrafine fibers of the fiber bundle after removing the sea component. As a result, the ultrafine fibers inside the fiber bundle are not restricted by the polymer elastomer, and thus, pile artificial leather having a soft touch can be obtained. It should be noted that when a polymer elastomer is impregnated and imparted to a non-woven fabric of ultrafine fibers of a fiber bundle formed by removing the sea component from sea-island type composite fibers, the polymer elastomer enters the voids of the fiber bundle, and thus, the ultrafine fibers inside the fiber bundle forming the fiber bundle are restricted by the polymer elastomer to obtain pile artificial leather having a hard touch.

[0056] Specific examples of the polymer elastomer include, for example: polyurethane, acrylonitrile elastomer, olefin elastomer, polyester elastomer, polyamide elastomer, acrylic elastomer, etc. Among them, polyurethane is particularly preferred. Specific examples of polyurethane include, for example: polycarbonate urethane, polyether urethane, polyester urethane, polyether ester urethane, polyether carbonate urethane, polyester carbonate urethane, etc. The polyurethane can be a polyurethane (solvent-based polyurethane) obtained by impregnating a non-woven fabric with a solution obtained by dissolving polyurethane in a solvent such as N,N-dimethylformamide (DMF) and then wet-curing the polyurethane; or it can be a polyurethane (aqueous polyurethane) obtained by impregnating a non-woven fabric with an emulsion obtained by dispersing polyurethane in water and then drying and curing it. Among them, from the viewpoint that even if the amount of polyurethane is increased, the polyurethane can be appropriately separated from the ultrafine fibers and it is easy to obtain pile artificial leather having a soft touch, solvent-based polyurethane is particularly preferred.

[0057] It should be noted that within the range not damaging the effects of the present invention, pigments such as carbon black, colorants such as dyes, solidification regulators, antioxidants, ultraviolet absorbers, fluorescent agents, mildew-proof agents, penetrants, defoaming agents, lubricants, waterproof agents, oil-proof agents, thickeners, extenders, curing accelerators, foaming agents, water-soluble high molecular compounds such as polyvinyl alcohol and carboxymethyl cellulose, inorganic fine particles, conductive agents, etc. can also be incorporated into the high molecular elastomer.

[0058] The content ratio of the high molecular elastomer impregnated into the pile artificial leather is 16 to 40% by mass. By containing the high molecular elastomer in such a ratio, a pile artificial leather with excellent balance between abrasion resistance and soft touch can be obtained.

[0059] The foaming ratio of the high molecular elastomer is preferably in the range of 0 to 5% by mass. When the high molecular elastomer is foamed at a high magnification, the high molecular elastomer surrounds the ultrafine fibers, so the filaments are less likely to come off, and the pilling resistance is further improved. However, since it is necessary to adjust additives or increase the solidification temperature, there is a tendency for the manufacturing cost to increase.

[0060] By removing the resin of the sea component from the non-woven fabric formed by bonding sea-island type composite fibers, a pile artificial leather substrate can be obtained, in which the ultrafine fibers forming the fiber bundle are not restricted by the high molecular elastomer and the non-woven fabric containing the aggregate of the ultrafine fibers and the high molecular elastomer impregnated into the non-woven fabric. As a method for removing the resin of the sea component from the sea-island type composite fibers, known methods for forming ultrafine fibers as follows can be used without particular limitation: treating the non-woven fabric formed by bonding sea-island type composite fibers with a solvent or decomposing agent capable of selectively removing only the resin of the sea component.

[0061] For the artificial leather substrate obtained in this way, it can be sliced into a given thickness as needed. The unit area weight of the artificial leather substrate obtained in this way is preferably 140 to 3000 g / m 2 , and more preferably 200 to 2000 g / m 2 .

[0062] In addition, by polishing one or both sides of the artificial leather substrate, which is a non-woven fabric of ultrafine fibers impregnated with a high molecular elastomer, a pile artificial leather substrate with a pile surface formed by raising the fibers on the surface layer can be obtained. The polishing is preferably carried out using sandpaper or emery paper with a grit size of 120 to 600, and more preferably about 320 to 600. Thereby, a pile artificial leather substrate having a pile surface with pile fibers on one or both sides can be obtained.

[0063] It should be noted that for the raised hair surface of the raised hair artificial leather substrate, in order to prevent the extremely fine fibers after raising on the raised hair surface from being prone to wire breakage and from being easily raised due to friction, thereby improving the appearance quality, a solvent that does not dissolve the extremely fine fibers but only swells or dissolves the polymer elastomer can be gravure-coated on the raised hair surface of the raised hair artificial leather substrate, so as to cement the extremely fine fiber bundles with the polymer elastomer. By coating the solvent as described above on the raised hair surface of the raised hair artificial leather substrate, the polymer elastomer around the extremely fine fiber bundles swells or dissolves, and the polymer elastomer infiltrates in a way that fills the gaps within the extremely fine fiber bundles. As the solvent, a solvent that does not dissolve the extremely fine fibers formed by polyester, polyamide, etc. but only swells or dissolves the polymer elastomer is selected. Specifically, for example, by using a mixed solvent of a good solvent for the polymer elastomer and a solvent with low dissolving ability, and adjusting the ratio of the good solvent to the solvent with low dissolving ability, the degree of adhesion between the polymer elastomer and the extremely fine fibers can be controlled.

[0064] For example, when the polymer elastomer is polyurethane, a mixed solution in any proportion of dimethylformamide (hereinafter referred to as DMF), tetrahydrofuran (hereinafter referred to as THF) as good solvents and acetone, toluene, cyclohexanone, ethyl acetate, butyl acetate, etc. with low dissolving ability can be used. As the mixing ratio of the good solvent to the solvent with low dissolving ability, it is appropriately selected in the range of 10:90 to 90:10 by weight ratio. As the temperature of the solvent during coating, the range of 10 to 60 °C is preferred.

[0065] In addition, a polymer elastomer can be further imparted to locally cement the vicinity of the roots of the extremely fine fibers after raising. Specifically, for example, by coating a solution or emulsion containing a polymer elastomer on the raised hair surface and then drying, the polymer elastomer is cured. By imparting a polymer elastomer to locally cement the vicinity of the roots of the extremely fine fibers after raising present on the raised hair surface, the vicinity of the roots of the fibers present on the raised hair surface is restricted by the polymer elastomer, and the extremely fine fibers become less likely to come loose. As a specific example of the polymer elastomer imparted to the raised hair surface, the same polymer elastomer as described above can be used. Considering the view that the roots of the extremely fine fibers can be firmly fixed without making the raised hair surface too hard, the amount of the polymer elastomer imparted to the raised hair surface is preferably 1 to 10 g / m 2 , and more preferably 2 to 8 g / m 2 .

[0066] It should be noted that the fixation of the ultra-fine fibers by the polymer elastomer means that when observing the cross-section in the thickness direction of the pile artificial leather using a scanning electron microscope, the ultra-fine fibers are fixed in a manner restricted by the polymer elastomer. In addition, the surface layer part refers to the area where the polymer elastomer is locally fixed near the root of the ultra-fine fibers. Specifically, for example, with respect to the total thickness of the pile artificial leather, it is the area within 10% or less, and further 5% or less in the thickness direction from the root of the pile. It should be noted that the total thickness of the pile artificial leather refers to the thickness excluding the pile.

[0067] For the pile artificial leather substrate with a pile surface, in order to further adjust the hand feeling, shrinkage processing for imparting softness, kneading softening processing, or finishing processing such as reverse sealing brushing treatment, antifouling treatment, hydrophilic treatment, lubricant treatment, softener treatment, antioxidant treatment, ultraviolet absorber treatment, fluorescent agent treatment, flame retardant treatment, etc. can also be carried out.

[0068] Dyeing the pile artificial leather substrate with a pile surface can produce pile artificial leather. The dye can be appropriately selected according to the type of ultra-fine fibers. For example, when the ultra-fine fibers are formed of a polyester resin, it is preferably dyed with disperse dyes or cationic dyes. Specific examples of disperse dyes include, for example: benzene azo dyes (monoazo, bisazo, etc.), heterocyclic azo dyes (thiazole azo, benzothiazole azo, quinoline azo, pyridine azo, imidazole azo, thiophene azo, etc.), anthraquinone dyes, condensed dyes (quinophthalone, styryl, coumarin, etc.). These dyes are commercially available as dyes with, for example, the prefix "Disperse". They can be used alone or in combination of two or more. In addition, as the dyeing method, a high-pressure liquid flow dyeing method, a jigger dyeing method, a hot melt continuous dyeing machine method, a dyeing method using a sublimation printing method, etc. can be used without particular limitation.

[0069] Thus, the pile artificial leather of this embodiment can be obtained. The fineness of the ultra-fine fibers forming the non-woven fabric contained in the pile artificial leather is 0.5 dtex or less, and the tensile strength is 6 - 9 mN. By including a non-woven fabric formed of a fiber bundle of such ultra-fine fibers, a pile artificial leather with both a beautiful pile appearance, high abrasion resistance, high friction discoloration resistance, and a soft hand feeling can be obtained.

[0070] The fineness of the ultrafine fibers forming the nonwoven fabric is 0.5 dtex or less, preferably 0.07 to 0.5 dtex, more preferably 0.1 to 0.3 dtex, and particularly preferably 0.15 to 0.25 dtex. When the fineness of the ultrafine fibers exceeds 0.5 dtex, it is difficult to obtain a beautiful flocked appearance. In addition, when the fineness of the ultrafine fibers is too low, there is a tendency for the abrasion resistance to deteriorate. It should be noted that the fineness is obtained as follows: A cross-section parallel to the thickness direction of the flocked artificial leather is photographed at a magnification of 3000 times using a scanning electron microscope (SEM), and the average value is calculated based on the diameters of 15 uniformly selected fibers using the density of the resin forming the fibers.

[0071] In addition, the tensile strength of the ultrafine fibers forming the nonwoven fabric is 6 to 9 mN, preferably 6.5 to 8 mN. When the tensile strength of the ultrafine fibers is less than 6 mN, the ultrafine fibers on the flocked surface become too easy to break, and when the flocked surface is rubbed by other objects, the flocks are likely to fall off, and the flocks will contaminate other objects, thereby reducing the rubbing fastness to color (rubbing color fastness). In addition, when the tensile strength of the ultrafine fibers exceeds 9 mN, the ultrafine fibers on the flocked surface become too difficult to break. When polishing is performed to form the flocked surface in the manufacturing process of the flocked artificial leather, the ultrafine fibers of the flocks become long, and it is difficult to obtain a beautiful flocked appearance, or when the flocked surface is rubbed by other objects, the ultrafine fibers are difficult to break, and the pilling resistance decreases.

[0072] It should be noted that the tensile strength of the ultrafine fibers is the tensile strength of each ultrafine fiber forming the flocked artificial leather on average. It is the maximum stress when measuring the s-s curve of each ultrafine fiber on average in the tensile strength mode at a slider speed of 1 mm / min using a micro tensile tester (Micro Autograph) as described later, and it is the average value of the maximum stresses measured for 5 ultrafine fibers.

[0073] In addition, the apparent density of the flocked artificial leather is 0.38 g / cm 3 or more, preferably 0.4 g / cm 3 or more, more preferably 0.4 to 0.7 g / cm 3 and particularly preferably 0.4 to 0.5 g / cm 3 and especially preferably 0.4 to 0.48 g / cm 3 . By setting the apparent density like this, a flocked artificial leather with an excellent balance between a fullness without dead folds and a soft hand feeling is obtained. When the apparent density of the flocked artificial leather is less than 0.38 g / cm 3In the case where the sense of fullness is low, dead folds are likely to occur, and fibers are likely to be pulled out due to the friction with the raised surface, making it difficult to obtain a beautiful raised appearance. In addition, when the apparent density of the raised artificial leather is too high, it is likely to be difficult to obtain a soft hand feeling.

[0074] For the raised artificial leather of this embodiment, it is preferable that the tensile strength of the ultra-fine fiber is the tensile strength A (mN) in the range of 6.5 to 8 mN, and the apparent density of the raised artificial leather is 0.38 to 0.48 g / cm 3 , and the content ratio B of the polymer elastomer satisfies 3.125×A ≤ B.

[0075] As shown in the following examples, in relation to the tensile strength A (mN) of the ultra-fine fiber in the range of 6.5 to 8 mN, by making the content ratio of the polymer elastomer satisfy the relational expression of 3.125×A ≤ B, and making the apparent density of the raised artificial leather be 0.38 to 0.48 g / cm 3 , a raised artificial leather with particularly high pilling resistance can be obtained.

[0076] Examples

[0077] Hereinafter, the present invention will be described more specifically by way of examples. It should be noted that the scope of the present invention is not subject to any limiting interpretation of the examples.

[0078] First, the evaluation methods used in this example are summarized and described below.

[0079] 〈Fineness〉

[0080] For fineness, a cross-section in the thickness direction of the raised artificial leather was photographed at 3000 times using a scanning electron microscope (SEM). Fifteen cross-sections of the ultra-fine fibers observed in the obtained images were randomly selected, the cross-sectional areas were measured, the average value of the cross-sectional areas was calculated, and the fineness was converted based on the density of each resin.

[0081] 〈Tensile Strength〉

[0082] The tensile strength of one ultra-fine fiber was measured at Shimadzu Testing Technology Co., Ltd. by the method described below. First, a mold frame 1 was prepared by cutting a rectangular window W with a height of 1 mm in the central part of a thick paper 1 as shown in Figure 1 (a). On the other hand, ultra-fine fibers 2 with a length of 3 mm or more forming a non-woven fabric were taken out from the cut artificial leather. Then, as shown in Figure 1 (b), the ultra-fine fibers 2 were fixed to the mold frame 1 with an adhesive 3 and an adhesive tape 4 in such a way that the ultra-fine fibers 2 passed vertically through the central part of the window W. Then, as shown in Figure 1As shown in (c), the frame C1 on one side of the forming window W of the mold frame 1 was cut with scissors. Then, in a gas atmosphere of 23°C and 50% RH, as Figure 1 shown in (d), the upper and lower frames of the mold frame 1 were respectively clamped between the upper and lower chucks 11 and 12 with a chuck distance of 1 cm of the Micro Autograph 10 (MST-X HR-U0.5N KIT, manufactured by Shimadzu Corporation). Then, as Figure 1 (e) and Figure 1 shown in (f), the other frame C2 of the forming window W of the mold frame 1 was also cut with scissors S. Then, as Figure 1 shown in (g), the stress when the slider 13 of the Micro Autograph 10 was raised at a speed of 1 mm / min was measured, and an s-s curve was plotted therefrom. The point where the s-s curve starts to rise was taken as the zero point. Then, the maximum stress in the s-s curve was obtained, and the average value of the maximum stresses of 5 ultra-fine fibers was taken as the tensile strength.

[0083] 〈Polymer elastomer content〉

[0084] The weight (W1) of about 10 g of a part of the pile artificial leather was measured. Then, this part was immersed in dimethylformamide for a certain period of time and then subjected to pressing treatment. By repeating the above process, polyurethane, that is, the polymer elastomer, was extracted. Then, the non-woven fabric as the remaining part after extraction was dried, and the weight (W2) of the dried non-woven fabric was measured. Then, the polymer elastomer content (B) was calculated according to the mathematical formula of polymer elastomer content (B) = (W1 - W2) / W1 × 100 (%).

[0085] 〈Apparent density〉

[0086] The thickness (mm) and the weight per unit area (g / cm 2 ) were measured in accordance with JIS L 1913, and the apparent density (g / cm 3 ) was calculated based on their values.

[0087] 〈Foaming ratio of polymer elastomer (polyurethane)〉

[0088] Using a scanning electron microscope (SEM), three photos were taken at a magnification of 300 times of the average position of the part 300 μm away from the surface of the cross-section parallel to the thickness direction of the pile artificial leather, and each image was printed on A4-sized paper. Then, the printed paper was overlapped on an OHP (Overhead projector) sheet. Then, on the OHP sheet, the foamed parts of polyurethane as a polymer elastomer were blackened and transferred. At this time, the voids containing fibers inside were regarded as the voids formed when the sea component was removed from the sea-island composite fiber and not regarded as foamed parts, and only the independent voids not containing fibers inside were regarded as foamed parts. Then, the pattern of the OHP sheet after blackening the foamed parts was obtained by a scanner to form an image.

[0089] In addition, the printed paper was overlapped on the OHP sheet, and all the areas where polyurethane existed and contained foamed parts on the OHP sheet were blackened and transferred. Then, the OHP sheet after blackening all the areas where polyurethane existed and contained foamed parts was obtained by a scanner to form an image.

[0090] Then, using an image processing device (image-pro plus, manufactured by Media Cybernetics), the total area of the blackened part of all the areas where polyurethane existed was obtained from the obtained image. In addition, the total area of the blackened part of the foamed parts was measured.

[0091] Then, based on the total area of the blackened part of all the areas where polyurethane existed and the total area of the blackened part of the foamed parts, the calculation was carried out by the formula: foaming rate of polyurethane (%) = total area of the blackened part of the foamed parts / total area of the blackened part of all the areas where polyurethane existed × 100.

[0092] 〈Intrinsic viscosity of the resin for forming ultrafine fibers〉

[0093] Regarding the intrinsic viscosity of the resin for forming ultrafine fibers, a solution was prepared by dissolving the resin in a mixed solvent of phenol / tetrachloroethane (volume ratio 1 / 1) as a solvent, and the viscosity of the solution was measured at 30 °C using an Ubbelohde viscometer (HRK-3 type manufactured by Hayashi Seisakusho) to obtain the intrinsic viscosity.

[0094] 〈Spinning draft〉

[0095] Let the ejection speed of the molten resin ejected from one hole of the spinning nozzle be A (g / min), the specific gravity of the molten resin be B (g / cm 3 ), the area of one hole be C (mm 2 ), and the spinning speed be D (m / min), and the calculation was carried out by the following formula.

[0096] ·Spinning draft = D / (A / B / C)

[0097] 〈Crocking〉

[0098] Using an ATLAS crockmeter CM-5 (manufactured by ATLAS ELECTRIC DEVICES CO), the crocking properties were measured both when dry and when wet.

[0099] The crocking fastness when dry was measured as follows.

[0100] A dry cotton white cloth was mounted on a glass friction member, and the cotton white cloth mounted on the friction member was brought into contact with the raised surface of the pile leather at a load of 900 g and reciprocated 10 times. Then, the cotton white cloth was removed, Cellotape (registered trademark) was pasted on the contaminated part, and a 1.5-pound cylindrical load was reciprocated once and then peeled off from the cotton white cloth.

[0101] On the other hand, the crocking fastness when wet was measured as follows.

[0102] A glass friction member was immersed in distilled water, and then a wet cotton white cloth with excess water removed was mounted. The cotton white cloth mounted on the friction member was brought into contact with the raised surface of the pile leather at a load of 900 g and reciprocated 10 times. Then, the cotton white cloth was removed, dried below 60°C, Cellotape was pasted on the contaminated part, a 1.5-pound cylindrical load was reciprocated once and then peeled off from the cotton white cloth.

[0103] Then, for the crocking fastness both when dry and when wet, the color change of the cotton white cloth was judged according to the staining gray scale (5 grades to 1 grade).

[0104] 〈Color fastness to rubbing〉

[0105] Using a Gakushin type friction tester, a white cloth was prepared in accordance with JIS L 0803, and the surface of the friction measurement piece was rubbed at a load of 200 g such that the friction member mounted with the white cloth reciprocated 30 times per minute for a travel distance of 10 cm, and 100 measurements were made (in accordance with JIS L 0849). The degree of staining contamination generated on the white cloth after 100 measurements was compared with the staining gray scale (in accordance with JIS L 0805), and it was judged as the DRY condition. For the measurement under the WET condition, the white cloth was immersed in distilled water for 10 minutes or more and then taken out, excess water was blotted with a filter paper, and a sample with no dripping was used, and the measurement was carried out by the same method as in the DRY condition, and the same judgment as in the DRY condition was made.

[0106] 〈Pilling resistance〉

[0107] According to JIS L 1096 (6.17.5E method, Martindale method), a test was conducted using a Martindale abrasion tester under the conditions of a pressing load of 12 kPa and 5000 abrasion cycles, and the grade evaluation was carried out according to the following criteria.

[0108] 5: No change

[0109] 4: Only pilling with a maximum diameter less than 1 mm occurred.

[0110] 3: Pilling with a maximum diameter of 1 - 3 mm occurred.

[0111] 2: Pilling with a maximum diameter of 3 - 5 mm occurred.

[0112] 1: A large amount of pilling with a maximum diameter exceeding 5 mm occurred.

[0113] 〈Abrasion amount〉

[0114] For the abrasion amount of the raised-pile artificial leather, according to JIS L 1096 (8.17.5E method, Martindale method), a wear test was carried out using a Martindale abrasion tester with a pressing load of 12 kPa (gf / cm 2 ), and 50,000 abrasion cycles, and the abrasion amount was measured.

[0115] 〈Softness〉

[0116] A softness tester (leather softness measuring device ST300: UK, manufactured by MSA Engineering System Co., Ltd.) was used to measure the softness and hardness. Specifically, a given ring with a diameter of 25 mm was set on the lower bracket of the device, and then the raised-pile artificial leather was set on the lower bracket of the device. Then, a metal needle (diameter 5 mm) fixed to the upper rod was pressed against the raised-pile artificial leather. Then, the upper rod was pressed down, and the values when the upper rod stopped were measured at 5 different positions and the average value was read. It should be noted that the value represents the penetration depth, and the larger the value, the softer it is.

[0117] 〈Hand feeling〉

[0118] The obtained raised-pile artificial leather was bent, and the hardness and softness touch were judged according to the following criteria.

[0119] A: It has a substantial feeling, no dead folds occurred, and it has an excellent softness hand feeling.

[0120] B: It belongs to any one or more of the hand feelings with a lack of substantial feeling, dead folds occurring, and being hard.

[0121] 〈Appearance〉

[0122] The appearance of the obtained raised artificial leather was judged according to the following criteria by visual observation and touch.

[0123] A: The fibers are delicate and loose, with a uniform length, and the raised surface has a soft and smooth touch.

[0124] B: The fibers are rough and loose, with a non-uniform length, and the raised surface has a rough touch and no luster.

[0125] [Example 1]

[0126] Polyethylene (PE) with a melt flow rate (MFR) of 25 (g / 10 min, 190 °C) was used as the resin for the sea component, and a composition obtained by adding 1.0 mass% of carbon black (CB) to polyethylene terephthalate (PET) with an intrinsic viscosity [η] = 0.67 (dl / g) and a melting point of 251 °C was prepared as the resin for the island component. Then, melt compound spinning was carried out at 285 °C so that the mass ratio of the sea component to the island component reached 35 / 65. Specifically, it was ejected from a spinning nozzle with a nozzle diameter (hole diameter) of 0.40 mm at a single-hole ejection rate of 1.5 g / min, and the ejector pressure was adjusted so that the spinning speed became 3450 m / min, and the long fibers were trapped on a net. Spinning was carried out at a spinning draft of 279, and thus a web of sea-island type composite fiber with a fineness of 4.3 dtex was obtained.

[0127] Then, the obtained webs were laminated to form a laminated web. Then, the laminated web was needled at a needling density of 2020 P / cm 2 using a 6-hook needle, and thus a bonded fiber sheet with a unit area weight of 810 g / m 2 was formed.

[0128] Then, the bonded fiber sheet was subjected to a shrinkage treatment in hot water at 90 °C, dried, and then hot-pressed, and thus a heat-shrunk bonded fiber sheet with a unit area weight of 912 g / m 2 , an apparent density of 0.389 g / cm 3 , and a thickness of 2.35 mm was obtained.

[0129] Then, a DMF solution (solid content 18.5 mass%) of a polycarbonate-based non-yellowing polyurethane with a 100% modulus of 4.5 MPa as a polymer elastomer was impregnated into the heat-shrunk bonded fiber sheet so that the proportion of the polymer elastomer relative to the raised artificial leather reached 32 mass%, and then it was immersed in a 30% DMF aqueous solution at 40 °C to solidify the polyurethane.

[0130] Next, while clamping the polyurethane-impregnated holding fiber sheet, it was immersed in toluene at 85°C to dissolve and remove the PE as the sea component, and further dried. In this way, a leatherette substrate with a basis weight of 837 g / m 2 、an apparent density of 0.437 g / cm 3 、and a thickness of 1.91 mm was obtained. This leatherette substrate is a composite of polyurethane and non-woven fabric, and the non-woven fabric is an aggregate of fiber bundles of long fibers of PET of ultra-fine fibers. It should be noted that since the non-woven fabric of ultra-fine fibers is formed by removing the sea component after impregnation with polyurethane, the ultra-fine fibers inside the fiber bundle are not adhered to each other by polyurethane and are not restricted by polyurethane.

[0131] Then, after cutting the leatherette substrate in half, a mixed solvent of DMF / cyclohexanone = 30 / 70 (weight ratio) was coated on the main surface that became the nap surface, and then dried, thereby causing the polyurethane to adhere to the ultra-fine fibers on its surface layer. Then, the cut-back side was ground with #120 paper and the main surface was ground with #320 and #600 paper, that is, both sides were ground, thereby finishing the leatherette substrate with a nap surface formed. Then, the leatherette substrate with a nap surface formed was dyed under high pressure at 120°C using disperse dyes, thereby obtaining a napped artificial leather with a suede-like nap surface. Then, the napped artificial leather was evaluated according to the above evaluation method. The results are shown in Table 1.

[0132]

[0133] [Examples 2 to 6, Comparative Examples 1 to 5]

[0134] In Examples 2 to 5 and Comparative Examples 1, 2, 4, and 5, the intrinsic viscosity, melting point of PET, or the spinning conditions of the sea-island composite fiber were set as shown in Table 1, thereby changing the fineness and tensile strength of the ultra-fine fibers. Except for this, napped artificial leather was obtained and evaluated in the same manner as in Example 1. In addition, in Example 6, the step of coating and drying a mixed solvent of DMF / cyclohexanone = 30 / 70 (weight ratio) on the main surface that became the nap surface in Example 1 was omitted. Except for this, napped artificial leather was similarly manufactured and evaluated. In addition, Comparative Example 3 is an example in which ultra-fine fibers were directly spun to form an aggregate of ultra-fine fibers, and the ultra-fine fibers were restricted by a high molecular elastomer. The results are shown in Table 1.

[0135] [Comparative Example 6]

[0136] A water-soluble polyvinyl alcohol resin (PVA; sea component) and a 6 mol% modified isophthalic acid-modified polyethylene terephthalate with an intrinsic viscosity [η] = 0.59 (dl / g) and a melting point of 240°C (island component) were prepared. Then, at 260°C, with a sea component / island component ratio of 25 / 75 (mass ratio), it was extruded from a melt composite spinning nozzle (number of islands: 12 islands / fiber) at a single-hole extrusion rate of 1.0 g / min. The spinneret pressure was adjusted so that the spinning speed was 3300 m / min, and long fibers with a fineness of 3.0 dtex were collected on a net to obtain a web of sea-island composite fibers.

[0137] The obtained web was cross-laid and laminated to obtain an overlapped body, and an anti-breaking needle oil agent was sprayed. Then, using a needle with 1 hook and a needle number of 42 and a needle with 6 hooks and a needle number of 42, the overlapped body was needled to make it hold together, thereby obtaining a held-together fiber sheet.

[0138] Next, the held-together fiber sheet was steam-treated under the conditions of 110°C and 23.5% RH. Then, after drying it in an oven at 90 - 110°C, it was further hot-pressed at 115°C to obtain a heat-shrunk held-together fiber sheet.

[0139] Next, an emulsion of a polycarbonate-based non-yellowing polyurethane with a 100% modulus of 4.5 MPa as a polymer elastomer (solid content 40 mass%) was impregnated into the heat-shrunk held-together fiber sheet so that the content ratio of the polymer elastomer reached 10 mass%, and then the polyurethane was dried and solidified. Next, while the held-together fiber sheet after being given polyurethane was subjected to a clamping treatment and a high-pressure water flow treatment, it was immersed in hot water at 95°C for 10 minutes to dissolve and remove the PVA as the sea component, and further dried. In this way, a synthetic leather substrate with a fineness of 0.11 dtex and an apparent density of 0.435 / cm 3 was obtained. The synthetic leather substrate is a composite of polyurethane and non-woven fabric, and the non-woven fabric is an aggregate of fiber bundles of ultrafine fiber long fibers.

[0140] Next, after cutting the artificial leather base material in half, a DMF solution of polyurethane (solid content 5%) was coated on the main surface that became the nap surface, and then dried, thereby adhering the polyurethane to the extremely fine fibers on its surface layer. Then, under the conditions of a speed of 3.0 m / min and a rotational speed of 650 rpm, the back surface of the paper cut in half with #120 was ground, and the main surface was ground with #240, #320, and #600 papers, that is, both surfaces were ground, thereby obtaining an artificial leather substrate with a nap surface. Then, using disperse dyes, the artificial leather substrate with a nap surface formed was subjected to high-pressure dyeing at 120 °C, thereby obtaining a nap artificial leather with a suede-like nap surface. Then, the nap artificial leather was evaluated according to the above evaluation method. The results are shown in Table 1.

[0141] [Comparative Example 7]

[0142] In Comparative Example 6, a 6 mol% modified isophthalic acid-modified polyethylene terephthalate with an intrinsic viscosity [η] = 0.67 (dl / g) and a melting point of 251 °C was used instead of a 6 mol% modified isophthalic acid-modified polyethylene terephthalate with an intrinsic viscosity [η] = 0.59 (dl / g) and a melting point of 240 °C. Except for this, an attempt was made to manufacture a nap artificial leather in the same manner as in Comparative Example 6. However, the stability of melt spinning was poor, and spinning could not be carried out.

[0143] Referring to Table 1, the nap artificial leathers of Examples 1 to 6 containing a non-woven fabric formed of extremely fine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN, and with the content ratio of the high molecular elastomer in the range of 16 to 40% by mass all satisfied: the appearance evaluation was A, having a beautiful nap appearance. In addition, the nap artificial leathers of Examples 1 to 6 all satisfied: the rubbing fastness to discoloration was 4 or more under the Dry condition and 3 - 4 or more under the Wet condition, and the color fastness to rubbing was 4 - 5 under the Dry condition and 3 - 4 or more under the Wet condition, having high rubbing fastness to discoloration. In addition, the nap artificial leathers of Examples 1 to 6 all satisfied: having a high abrasion resistance with a wear amount of 40 mg or less. Furthermore, the nap artificial leathers of Examples 1 to 6 all satisfied: the softness was 4.0 mm or more, having a soft hand feeling. Thus, the nap artificial leathers of Examples 1 to 6 with extremely fine fibers having a fineness of 0.5 dtex or less and a tensile strength of 6 to 9 mN, and with the content ratio of the high molecular elastomer in the range of 16 to 40% by mass and the extremely fine fibers forming fiber bundles in the regions other than the surface layer not being restricted by the high molecular elastomer were all nap artificial leathers with a beautiful nap appearance, high abrasion resistance, high rubbing fastness to discoloration, and a soft hand feeling.

[0144] On the other hand, the abrasion loss of the flocked artificial leather of Comparative Example 1 containing a non-woven fabric formed of ultra-fine fibers with a fineness of 0.5 dtex or less but a tensile strength of less than 6 mN was 65.2 mg, and the abrasion resistance was low. It had a low rubbing fastness to discoloration of grade 3 under Wet conditions and a rubbing fastness to color of grade 2-3 under Wet conditions. In addition, the appearance evaluation of the flocked artificial leather of Comparative Example 2 containing a non-woven fabric formed of ultra-fine fibers with a fineness of 0.5 dtex or less but a tensile strength exceeding 9 mN was B, and it did not have a beautiful flocked appearance. Similarly, for the flocked artificial leather of Comparative Example 3 containing a non-woven fabric formed of ultra-fine fibers with a fineness exceeding 0.5 dtex and a tensile strength of 21 mN, and the ultra-fine fibers were restricted by a polymer elastomer, the appearance evaluation was also B, and it did not have a beautiful flocked appearance. In addition, for the flocked artificial leather of Comparative Example 4 containing a non-woven fabric formed of ultra-fine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6.5 mN, but the proportion of the polymer elastomer was 15% by mass, although the abrasion loss was 53.3 mg and it had a certain degree of abrasion resistance, the appearance evaluation was also B, and it did not have a beautiful flocked appearance. In addition, for the flocked artificial leather of Comparative Example 5 containing a non-woven fabric formed of ultra-fine fibers with a fineness of 0.5 dtex or less and a tensile strength of 6.4 mN, but the proportion of the polymer elastomer was 43% by mass, the appearance evaluation was B, and it did not have a beautiful flocked appearance. In addition, for the flocked artificial leather of Comparative Example 6 containing a non-woven fabric formed of ultra-fine fibers with a fineness of 0.5 dtex or less but a tensile strength of 5.3 mN, and the proportion of the polymer elastomer was 10% by mass, the abrasion loss was 76 mg, the abrasion resistance was low, and it had a low rubbing fastness to discoloration of grade 1-2 under Wet conditions and a rubbing fastness to color of grade 1 under Wet conditions.

[0145] [Example 7]

[0146] Polyethylene (PE) with a melt flow rate (MFR) of 25 (g / 10 min, 190 °C) was used as the sea component, and a composition obtained by adding 1.0% by mass of carbon black (CB) to polyethylene terephthalate (PET) with an intrinsic viscosity [η] = 0.67 (dl / g) and a melting point of 251 °C was prepared as the island component. Then, melt compound spinning was carried out at 260 °C such that the sea component / island component reached 35 / 65 (mass ratio). Specifically, it was ejected from a spinning nozzle with a pore diameter of 0.40 mm at a single-hole ejection amount of 1.5 g / min (number of islands: 12 islands / fiber), and the spinneret pressure was adjusted to make the spinning speed reach 3450 m / min, and the long fibers were trapped on a net. Spinning was carried out under a spinning draft of 279, and thus a web of sea-island type composite fibers with a fineness of 4.5 dtex was obtained.

[0147] Then, the total unit area weight was made to reach 600 g / m 2The obtained nets are laminated by cross-laying to form a laminated net. Then, needles with 1 hook and needle number 42 and needles with 6 hooks and needle number 42 are used to needled the overlapping body at 4189 needles / cm 2 to make it hold together, thereby forming a cohered fiber sheet with a basis weight of 840 g / m 2 .

[0148] Then, the cohered fiber sheet is subjected to a shrinkage treatment in hot water at 90 °C, dried in an oven at 90 - 110 °C, and then pressed with a roller, thereby obtaining a heat-shrunk net cohered sheet with a basis weight of 940 g / m 2 , an apparent density of 0.40 g / cm 3 and a thickness of 2.35 mm.

[0149] Then, a DMF solution (solid content 18.5%) of polycarbonate-based non-yellowing polyurethane with a 100% modulus of 3.2 MPa as a polymer elastomer is impregnated into the heat-shrunk cohered fiber sheet so that the content ratio of polyurethane to the raised artificial leather reaches 32% by mass, and then it is impregnated into a 30% aqueous solution of DMF at 40 °C to solidify the polyurethane.

[0150] Next, while clamping the cohered fiber sheet after polyurethane is imparted, it is impregnated into toluene at 90 °C to dissolve and remove the PE as the sea component, and further dried. In this way, an artificial leather substrate with a basis weight of 810 g / m 2 , an apparent density of 0.458 g / cm 3 and a thickness of 1.77 mm is obtained. It is a composite of polyurethane and a non-woven fabric, and the non-woven fabric is a cohered body of a fiber bundle of long fibers of PET of ultrafine fibers. It should be noted that the non-woven fabric of ultrafine fibers is formed by impregnating and then removing the sea component after polyurethane is imparted. Therefore, the ultrafine fibers inside the fiber bundle are not adhered to each other by polyurethane, and the ultrafine fibers are not restricted.

[0151] Then, the artificial leather substrate is cut in half, and a mixed solvent of DMF / cyclohexanone = 30 / 70 (weight ratio) is coated on the main surface that becomes the raised surface and dried. Thus, the polyurethane is adhered to the ultrafine fibers on its surface layer. Then, the cut-back side is ground using #120 paper, and the main surface is ground using #240, #320, and #600, that is, both sides are ground, thereby finishing the artificial leather substrate with a raised surface. Then, using disperse dyes, the artificial leather substrate with a raised surface is subjected to high-pressure dyeing at 120 °C, thereby obtaining a raised artificial leather with a suede-like raised surface. Then, the raised artificial leather was evaluated according to the above evaluation method. The results are shown in Table 2.

[0152]

[0153] [Examples 8 to 22, 24 to 33, Comparative Examples 8 to 10]

[0154] In Examples 8 to 19, 21 to 22, 24 to 33, and Comparative Examples 8 to 10, the intrinsic viscosity, melting point, content ratio of CB, or the spinning conditions of the sea-island composite fiber, the content ratio of the polymer elastomer, the coating and drying of the mixed solvent of DMF / cyclohexanone, etc. were set as shown in Table 2 or Table 3 below. Other than that, a flocked artificial leather was obtained and evaluated in the same manner as in Example 7. In addition, in Example 20, the sea-island composite fiber after melt spinning was crimped and cut, and the raw cotton of the short fibers of the obtained sea-island composite fiber was carded to form a web of short fibers. Other than that, a flocked artificial leather was obtained and evaluated in the same manner as in Example 7. The evaluation results are shown in Table 2 or Table 3 below.

[0155]

[0156] [Example 23, Comparative Example 11]

[0157] In Example 23 and Comparative Example 11, the intrinsic viscosity of PET, the spinning conditions of the sea-island composite fiber, the content ratio of the polymer elastomer, the coating and drying of the mixed solvent of DMF / cyclohexanone, etc. were set as shown in Table 3. Other than that, a flocked artificial leather was obtained and evaluated in the same manner as in Comparative Example 6. The evaluation results are shown in Table 3.

[0158] Figure 2 The figure showing the content ratio (B) of the polymer elastomer plotted against the tensile strength (A) of the ultrafine fibers contained in the flocked artificial leather described in Table 2 is shown. In addition, Figure 3 The figure showing the content ratio (B) of the polymer elastomer plotted against the tensile strength (A) of the ultrafine fibers contained in the flocked artificial leather described in Table 3 is shown.

[0159] Referring to Table 2, the flocked artificial leathers obtained in Examples 7 to 20 are as Figure 2 shown, having a tensile strength (A) in the range of 6.5 to 8 mN, and the content ratio (B)% of the polymer elastomer satisfies 3.125×(A) ≤ (B). Referring to Table 2, these flocked artificial leathers are flocked artificial leathers with excellent properties, including high pilling resistance of 4 or more grades, high abrasion resistance with a wear amount of 40 mg or less, a soft hand feeling with a softness of 3.7 mm or more, fine and loose fibers with a uniform length, and a beautiful flocked appearance with a soft and smooth touch.

[0160] In addition, referring to Table 3, Examples 21, 22, 24 to 27, and 28 to 33 are as Figure 3 shown, having a tensile strength (A) in the range of 6.5 to 8 mN, and the content ratio (B)% of the polymer elastomer does not satisfy 3.125 × (A) ≤ (B). Referring to Table 3, the pilling resistance or abrasion resistance of these flocked artificial leathers is somewhat low. In addition, the feel of Example 23 with a high apparent density is hard.

Claims

1. A pilose artificial leather, which comprises a non-woven fabric as an aggregate of ultrafine fibers and a polymer elastomer imparted to the non-woven fabric, and has a pilose surface formed by raising the ultrafine fibers on at least one side, the fineness of the ultrafine fibers is 0.15 to 0.5 dtex, and the tensile strength A is 6.5 to 8 mN. A plurality of the ultrafine fibers form a fiber bundle, and the unit of A is mN, in a region other than the surface layer portion, the ultrafine fibers forming the fiber bundle are not restricted by the polymer elastomer, the content ratio B of the polymer elastomer is 16 to 40% by mass, and 3.125 × A ≤ B is satisfied, and the unit of B is % by mass, The apparent density of the pile artificial leather is 0.38 to 0.48 g / cm 3 .

2. The pilose artificial leather according to claim 1, wherein, the polymer elastomer is a solvent-based polyurethane.

3. The pilose artificial leather according to claim 1 or 2, wherein, the foaming ratio of the polymer elastomer is 0 to 5% by mass.

4. The pilose artificial leather according to claim 1 or 2, wherein, a part of the polymer elastomer present in the surface layer portion is adhered near the root of the ultrafine fibers after raising.

5. The pilose artificial leather according to claim 1 or 2, wherein, the ultrafine fibers are ultrafine fibers formed by dissolving and removing the sea component from sea-island type composite fibers with an organic solvent.

6. The pilose artificial leather according to claim 1 or 2, wherein, the non-woven fabric is a spunbond non-woven fabric containing the ultrafine fibers of long fibers.

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