JP2014005564A - Grained artificial leather and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide grained artificial leather which develops flexibility similar to that of natural leather with a high-class feeling and a bend crease appearance while keeping a high peel strength of a grain surface layer.SOLUTION: The grained artificial leather includes: an artificial leather substrate including a fiber entangled body of an ultrafine fiber having an average fineness of 0.001 to 0.5 decitex and a first polymer elastic body impregnated in and applied to the fiber entangled body; and a grain surface layer including a second polymer elastic body formed on the surface of the artificial leather substrate. In a virtual cross section perpendicular to the thickness direction of the surface of the side which contacts the grain surface layer of the artificial leather substrate, the number density of the ultrafine fibers in the cross section is 1000/mmor more on average, and an area ratio of the first polymer elastic body which is exposed on the surface is 20% or less on average.

Description

  The present invention relates to a silver-tone artificial leather having both high peel strength of a silver surface layer and flexibility and foldability similar to natural leather having a high-class feeling and a method for producing the same.

  Conventionally, a silver-coated artificial artificial material obtained by forming a silver surface layer made of a polymer elastic body such as polyurethane elastomer on the surface of an artificial leather base material in which a fiber entangled body is impregnated with a polymer elastic body such as polyurethane elastomer. Leather is known.

  As an artificial leather base material, various improvements have been made in order to approximate the texture of natural leather with a high-class feeling. Specifically, for example, an artificial leather base material excellent in flexibility and fullness obtained by impregnating an elastic resin into a fiber entangled body made of ultrafine fibers of 1 dtex or less and wet coagulating is known. Further, as a flexible artificial leather base material, a fiber entanglement made of ultrafine fibers obtained by selectively removing only the sea component from a fiber entanglement of sea island type fiber containing polyethylene or the like that can be selectively extracted as a sea component. Artificial leather substrates containing coalescence are also known.

  On the other hand, various silver surface layers formed on the surface of an artificial leather substrate are also known. The silver layer is generally required to have high peel strength and high wear resistance. In order to improve the peel strength and wear resistance, a method for improving the peel strength and wear resistance by increasing the thickness of the silver surface layer is known. However, if the silver layer is too thick, the softness of the artificial leather with silver will decrease, or the crease will appear as if the silver layer has been lifted away from the texture of the natural leather. There was a problem.

  As a technique for improving the flexibility of a silver-finished artificial leather, for example, the following Patent Document 1 discloses a fibrous sheet having a three-dimensional entangled structure composed of polyamide ultrafine fibers having a single fiber fineness of 0.2 denier or less. A method for producing a flexible leather-like sheet is disclosed in which a urethane polymer is applied to at least one surface of the material to form a silver surface, and then subjected to a shrinkage treatment by drying with an emulsion of an aromatic alcohol and drying. Patent Document 2 below is a weft knitted fabric in which a fiber base material layer has a double-sided knitted structure in a synthetic leather in which a polyurethane resin skin layer is laminated on a fiber base material surface via a polyurethane resin adhesive layer, and Disclosed is a synthetic leather in which the polyurethane resin forming the polyurethane resin skin layer is a silicone-modified non-yellowing polycarbonate polyurethane resin. Patent Document 3 below is characterized in that a coating layer made of polyurethane resin is formed on a fibrous base material made of ultrafine fibers and a polymer elastic body, and then a solvent-based paint containing a nitrocellulose derivative is applied. Disclosed is a method for producing a silver-finished leather-like sheet.

  In artificial leather with a silver tone, high peel strength and abrasion resistance are often contradictory to the sensibility aspects such as excellent flexibility and crease, and it is difficult to balance these in a balanced manner. Neither method has solved such a problem.

Japanese Patent Publication No.06-94629 Japanese Patent Laid-Open No. 9-31862 JP-A-2005-171451

  As mentioned above, if the silver surface layer is made too thick in order to improve the peel strength and abrasion resistance of the silver layer in the silver-tone artificial leather, the flexibility of the silver-tone artificial leather decreases, There was a tendency for folds to appear as if the silver surface layer was raised. The present invention solves such problems, that is, a silver-tone artificial leather that exhibits flexibility and crease feeling similar to high-quality natural leather while maintaining high peel strength of the silver layer. The purpose is to provide.

  The present inventors have intensively studied means for improving the texture such as flexibility and crease feeling while maintaining a high peel strength of the silver surface layer. Among them, it was found that the silver surface layer of the silver-tone artificial leather partially lifted or peeled off from the artificial leather substrate due to bending. And as a result of earnestly examining such means for suppressing partial lifting and peeling of the silver layer, the present invention has been conceived.

That is, one aspect of the present invention is an artificial leather base material comprising a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement. A virtual cross section perpendicular to the thickness direction of the surface on the side in contact with the silver surface layer of the artificial leather base material, the silver surface layer containing the second polymer elastic body formed on the surface of the artificial leather base material In which the number density of the cross-section of the ultrafine fibers is an average of 1000 / mm ² or more and the area ratio of the first polymer elastic body exposed on the surface is an average of 20% or less It is leather. In such a silver-tone artificial leather, a large number of ultrafine fibers that are raised in a direction perpendicular to the thickness direction are present on the surface of the artificial leather base material in contact with the silver surface layer. In addition, the proportion of ultrafine fibers held by the second polymer elastic body forming the silver surface layer increases. In addition, since there are not too many first polymer elastic bodies on the surface of the artificial leather base on the side in contact with the silver surface layer, the second polymer elastic body forming the silver surface layer is an artificial leather base. It penetrates sufficiently to the inner layer of the material. As a result, the silver surface layer is densely and firmly fixed by the anchor effect of the ultrafine fibers, and maintains a high peel strength, and the silver surface layer is difficult to lift.

  The ultrafine fibers form a fiber bundle, and it is preferable that the average length of the lying fiber bundle is 200 μm or less among the fiber bundles observed in the virtual cross section. The lying fiber bundle whose average length exceeds 200 μm is a part of the fiber entangled body, but is not sufficiently entangled. Accordingly, when the silver surface layer is fixed to a lying fiber bundle having an average length exceeding 200 μm, the effect of improving the peel strength of the silver surface layer tends to be reduced.

In addition, when the number density of the cross-section of the ultrafine fibers is 3000 / mm ^{2 on} average, the number density of the ultrafine fibers that have penetrated into the silver face layer is increased, so that the silver face layer is made of ultrafine fibers. Reinforcement increases wear resistance.

Another aspect of the present invention is an artificial leather comprising a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement. A first step for producing an intermediate sheet of the base material, a second step for performing surface adjustment by adjusting the thickness of the intermediate sheet, and a second polymer elastic body on the exposed surface formed by the surface exposure A third step of forming a silver surface layer, and in the observation surface when the exposed surface is observed with a scanning electron microscope, the average number density of the cross-section of the ultrafine fibers is 1000 pieces / mm ² or more, and The method for producing silver-finished artificial leather is adjusted so that the area ratio of the first polymer elastic body is an average ratio of 20% or less. According to such a method, the surface of the exposed surface formed is aligned in a raised manner to expose a large number of ultrafine fibers, and the ratio of the ultrafine fibers held by the second polymer elastic body is Get higher. In addition, since the first polymer elastic body does not appear much in the vicinity of the exposed surface, the second polymer elastic body sufficiently penetrates into the artificial leather substrate when forming the silver layer. It becomes easy. As a result, the silver surface layer is densely and firmly fixed by the anchor effect of the ultrafine fibers, maintains high peel strength, and makes the silver surface layer difficult to lift.

  Further, the ultrafine fibers form a fiber bundle, and the second step is such that the average length of the lying fiber bundle is 200 μm or less among the fiber bundles observed on the SEM observation surface of the exposed surface. It is preferable to provide the process of taking out. The lying fiber bundle with an average length of more than 200 μm is part of the fiber entanglement, but not fully entangled. Accordingly, when the second polymer elastic body forming the silver surface layer is held by such a fiber bundle and fixed, the silver surface layer tends to float or peel easily. Therefore, by removing the lying fiber bundle having an average length of more than 200 μm before the formation of the silver layer, the second polymer elastic body forming the silver layer is formed of a sufficiently entangled ultrafine fiber. It becomes easier to grip. Further, when a long fiber bundle lies on the exposed surface, the second polymer elastic body forming the silver layer is not sufficiently penetrated into the artificial leather substrate. Therefore, by removing such a fiber bundle, the second polymer elastic body forming the silver layer easily penetrates into the artificial leather substrate.

  In the second step, the surface of the artificial leather substrate is chamfered so that the average nap length of the ultrafine fibers raised from the exposed surface is 150 μm or less on the observation surface of the cross section parallel to the thickness direction of the artificial leather base. It is preferable to provide a process. In such a case, the second polymer elastic body for forming the silver surface layer sufficiently grips the ultrafine fibers that lie on the exposed surface, and the peel strength is further improved, There is a tendency that the second polymer elastic body forming the silver layer easily penetrates into the inside of the artificial leather base material, and tends to easily grasp the sufficiently entangled ultrafine fibers.

  The first step is a step of forming an ultrafine fiber generating fiber entangled body capable of forming ultrafine fibers, and an emulsion of the first polymer elastic body having heat-sensitive gelling property on the ultrafine fiber generating fiber entangled body. And impregnating and gelling the emulsion, followed by drying, and converting the ultrafine fiber-generating fiber entangled body into a fiber entangled body of ultrafine fibers. The amount (mass ratio) of the fibers is preferably 5/95 to 30/70. When the emulsion of the polymer elastic body has a heat-sensitive gelation property, the emulsion gels without being migrated by heating. When an ordinary emulsion is impregnated into a fiber entangled fiber and dried, the emulsion in the inner layer moves to the surface layer of the fiber entangled fiber as the drying of the emulsion proceeds from the surface, and the polymer elasticity of the surface layer A phenomenon called migration that increases body concentration occurs. According to the production method of the present invention, migration of the emulsion to the surface layer due to thermal gelation is suppressed. Thereby, the polymer elastic body can be uniformly present in the thickness direction without being ubiquitous on the surface layer of the ultrafine fiber generating fiber entangled body. At this time, by adjusting in advance such that the amount of the first polymer elastic body / the amount (mass ratio) of the ultrafine fibers is 5/95 to 30/70, the polymer elastic body on the SEM observation surface of the exposed surface It becomes easy to make the area ratio of 20% or less.

  In addition, the third step is a step of forming a silver surface layer by laminating a silver surface skin layer film formed in advance on the exposed surface via an adhesive layer. It is preferable because it is easy to stabilize.

  ADVANTAGE OF THE INVENTION According to this invention, the silver-tone artificial leather which can express the softness | flexibility and crease feeling similar to high-quality natural leather, maintaining the high peeling strength of a silver surface layer is obtained.

The schematic cross section of the cross section parallel to the thickness direction of the silver-tone artificial leather of this embodiment is shown. 2 is a scanning electron microscope (SEM) photograph of a sliced surface of an artificial leather base material obtained in Example 1. FIG. 2 is a SEM photograph of a cross section in the thickness direction of an artificial leather base material obtained in Example 1. FIG. 4 is a SEM photograph of a cross section in the thickness direction of a slice surface obtained in Example 3. FIG.

  In the silver-tone artificial leather according to the present invention, for example, as shown in the schematic cross-sectional view of FIG. 1, the ultrafine fibers 1 a forming the fiber entanglement in the artificial leather base material 1 enter the silver surface layer 2. Yes. As a result, the silver layer 2 is firmly fixed by the anchor effect of the ultrafine fibers 1a. An embodiment of a silver-tone artificial leather according to the present invention will be described in detail while explaining its production method.

The silver-tone artificial leather of the present embodiment includes, for example, a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement. A first step of producing an intermediate sheet of an artificial leather base material, a second step of performing a surface adjustment by adjusting the thickness of the intermediate sheet, and a second polymer elastic body on the exposed surface formed by the surface alignment And a third step of forming a silver surface layer containing, on the observation surface when the exposed surface is observed with a scanning electron microscope, the average number density of the cross-section of the ultrafine fibers is 1000 pieces / mm ² or more And it manufactures by adjusting so that the area ratio of a 1st polymeric elastic body may become a ratio of 20% or less on average. Hereinafter, each process is demonstrated in order.

  The first step is an artificial leather-based intermediate sheet comprising a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement. Is a process of manufacturing.

  In the production of the intermediate sheet, first, a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex is produced. The shape of the fiber constituting the fiber entangled body is not particularly limited, but from the viewpoint of improving the crease and surface quality of the artificial leather with silver tone, the sea-island type fiber obtained by using a method such as a mixed spinning method or a composite spinning method is used. It is preferable that it is an ultrafine fiber obtained by making such an ultrafine fiber generation type fiber ultrafine. Specifically, for example, melt spinning a microfiber-generating fiber such as a sea-island type fiber including a sea component made of a selectively removable resin and an island component made of a resin for forming a microfiber, A fiber web is produced.

  In addition, in this embodiment, although the case where a sea island type fiber is used as an ultra fine fiber generation type fiber is explained in detail, even if an ultra fine fiber generation type fiber other than a sea island type fiber is used, an ultra fine fiber generation type fiber is used. Alternatively, the fine fiber may be directly spun. In addition, as a specific example of the ultrafine fiber generating type fiber other than the sea-island type fiber, a plurality of ultrafine fibers are formed by lightly bonding immediately after spinning, and a plurality of ultrafine fibers are formed by unraveling by mechanical operation. Examples of such a separation-dividing fiber and a petal-type fiber in which a plurality of resins are alternately gathered in a petal shape in the melt spinning process are used, and any fiber that can form ultrafine fibers is used without particular limitation. .

  Specific examples of the resin for forming ultrafine fibers, which are island components of sea island type fibers, include, for example, polyethylene terephthalate (PET), isophthalic acid modified PET, sulfoisophthalic acid modified PET, polybutylene terephthalate, polyhexamethylene terephthalate. Aromatic polyester such as polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalylate copolymer, etc .; polyamide 6, polyamide 66, polyamide 10 Polyamides such as polyamide 11, polyamide 12 and polyamide 6-12; polyolefins such as polypropylene, polyethylene, polybutene, polymethylpentene and chlorinated polyolefin; ethylene units Modified polyvinyl alcohol and modified polyvinyl alcohol containing 5 to 70 mol%; and polyurethane elastomer, polyamide elastomer, and a thermoplastic resin such as an elastomer such as polyester elastomer. These thermoplastic resins may be used alone or in combination of two or more. Among these, PET, isophthalic acid-modified PET, polylactic acid, polyamide 6, polyamide 12, polyamide 6-12, a copolymer of these polyamides, and polypropylene are excellent in productivity such as spinnability, and can be obtained with a silver coating. It is preferable from the viewpoint of excellent mechanical properties of artificial leather.

  It should be noted that the resin for forming the ultrafine fiber is various additives within a range not impairing the object and effect of the present invention, specifically, for example, a catalyst, an anti-coloring agent, a heat-resistant agent, a flame retardant, a lubricant, Antifouling agent, fluorescent brightening agent, matting agent, coloring agent, gloss improver, antistatic agent, fragrance, deodorant, antibacterial agent, acaricide, inorganic fine particles etc. may be blended as required Good.

  The sea component of the sea-island fiber is a component that is selectively extracted and removed by a solvent or selectively decomposed and removed by hot water or a decomposing agent when the sea-island fiber is converted into a fiber bundle of ultrafine fibers. . Therefore, as the resin that forms the sea component, a resin that has higher extraction and removal properties by the solvent and decomposition and removal properties by hot water or a decomposing agent than the resin that forms the island components is selected. In addition, from the viewpoint of spinning stability of sea-island type fibers, the resin has a low affinity with the resin that forms the island component, and the melt viscosity and / or surface tension is lower than the resin that forms the island component under the spinning conditions. Is preferably used.

  Specific examples of the resin for forming the sea component of such sea-island fibers include, for example, polyethylene, polypropylene, polystyrene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, styrene-ethylene copolymer. , Styrene-acrylic copolymer, and polyvinyl alcohol resins such as water-soluble thermoplastic polyvinyl alcohol (water-soluble PVA). Among these, water-soluble PVA is particularly preferable because it can be produced without using an organic solvent.

  The saponification degree of the water-soluble PVA resin is 90 to 99.99 mol%, more preferably 93 to 99.98 mol%, particularly 94 to 99.97 mol%, particularly 96 to 99.96 mol%. % Is preferable. When the degree of saponification of the water-soluble PVA resin is within such a range, the water-soluble PVA resin is excellent in water solubility, excellent in thermal stability, excellent in melt spinnability, and excellent in biodegradability. Is obtained.

  As a method for forming a fiber web, a method of forming a long fiber web without cutting ultrafine fiber generating long fibers such as sea-island long fibers spun by a spunbond method or the like is preferably used.

  For example, sea-island long fibers are extruded from a spinneret for sea-component polymer and island-component polymer, melt-spun, and after the molten sea-island long fibers discharged from the base are cooled by a cooling device, an air jet nozzle, etc. By using a suction device of the above, it is pulled and refined by a high-speed air current at a speed corresponding to a take-up speed of 1000 to 6000 m / min so as to achieve a desired fineness, and is deposited on a collection surface such as a mobile net. To form an unstretched long fiber web. In addition, if necessary, the obtained long fiber web may be partially crimped, for example, by pressing to stabilize the form. Such a long fiber web manufacturing method is advantageous in production because it does not require a series of large-scale equipment such as a raw cotton supply device, a fiber opening device, and a card machine, which is essential in the conventional fiber web manufacturing method using short fibers. . In addition, since the long fiber web and the artificial leather obtained by using the same tend to have low fiber bulk and tend to have high fiber density, the conventional short fiber web and artificial manufactured using the same are used. Compared to leather, it excels in mechanical properties such as peel strength. In addition, by increasing the density of the long fibers, it is easy to reproduce the fullness and fine creases that resemble natural leather.

  The spinning temperature (die temperature) in melt spinning is, for example, higher than the melting points of the sea component and island component resins, and the range of 180 to 350 ° C. is likely to cause a melting point peak and a sub-endothermic peak to exist. To preferred.

The average cross-sectional area of the sea-island long fibers is not particularly limited, but is preferably 30 to 800 μm ² . The average area ratio between the sea component and the island component in the cross section corresponding to the volume ratio between the sea component and the island component of the sea-island long fibers is not particularly limited, but is preferably 5/95 to 70/30. Moreover, although the fabric weight of the obtained long fiber web is not specifically limited, 10-1000 g / m < ² > is preferable.

A web entangled sheet, which is an entangled body of ultrafine fiber-generating fibers, is formed by stacking a plurality of the long fiber webs obtained as described above and performing an entanglement treatment. Specifically, after a plurality of long fiber webs are stacked in the thickness direction using a cross wrapper or the like, needle punching is performed under the condition that at least one barb penetrates from both outer sides simultaneously or alternately. At this time, by adjusting the punching density when the needle is driven in the direction perpendicular to the thickness direction, etc., the cross section of the ultrafine fibers is adjusted to be exposed to 1000 / mm ² or more on the slice surface to be formed later. be able to. The punching density is not particularly limited, but is preferably in the range of 500 to 5000 punches / cm ² from the viewpoint that the fibers can be sufficiently entangled while suppressing damage to the sea-island long fibers by the needle.

By such a process, the sea-island long fibers are entangled three-dimensionally, and the sea-island long fibers are present at an average density of, for example, 600 to 4000 / mm ² in a cross section parallel to the thickness direction. Thus, an entangled long fiber web in which sea-island type long fibers are gathered very densely is obtained. The basis weight of the entangled long fiber web is preferably 100 to 2000 g / m ² . The long fiber web may be provided with a silicone oil agent or a mineral oil oil agent such as a needle breakage preventing oil agent, an antistatic oil agent, or an entanglement improving oil agent at any stage from the production to the entanglement treatment. preferable.

  The entangled long fiber web is preferably subjected to a heat shrink treatment. By such heat shrinking treatment, the entangled state of the long fiber web is further densified, the shape retention is improved, and the fibers are prevented from coming off.

  Examples of the heat shrink treatment include heat shrink treatment with water vapor and treatment immersed in warm water at 70 to 150 ° C., and heat shrink treatment with water vapor is particularly preferable. The heat shrink treatment with water vapor is performed, for example, by adding moisture to the entangled long fiber web so that the sea component is 10 to 200% by mass, and then the relative humidity is 70% or more, and further 90% or more. It is preferable to heat-treat for 60 to 600 seconds in a heated steam atmosphere of 60 to 130 ° C. When the heat shrink treatment is performed under such conditions, the sea component resin plasticized with water vapor is compressed and deformed by the shrinkage force of the long fibers of the island component resin and becomes denser.

As a shrinkage rate of the entangled long fiber web by the heat shrink treatment, the following formula:
[(Area before shrinkage treatment−Area after shrinkage treatment) / Area before shrinkage treatment] × 100
Is preferably 35% or more, more preferably 35 to 90%, and particularly preferably 40 to 80%.

  And the 1st polymeric elastic body is impregnated and given to the web entanglement sheet which is the fiber entanglement body of the long fiber web obtained as mentioned above. Specifically, for example, the web entangled sheet is impregnated with a liquid containing the first polymer elastic body, and then the first polymer elastic body is solidified, whereby the web entangled sheet has the first The polymer elastic body is impregnated.

  As the first polymer elastic body, a polymer elastic body conventionally used when producing an artificial leather base material can be used without any particular limitation. Specific examples thereof include a polyurethane resin, an acrylic resin, a polyamide resin such as a polyamide elastomer, a polyester resin such as a polyester elastomer, an elastic polystyrene resin, an elastic polyolefin resin, and the like. These may be used alone or in combination of two or more. Among these, polyurethane resins are particularly preferable because they are excellent in flexibility and fulfillment.

  As a specific example of the method for impregnating the web entangled sheet with the first polymer elastic body, for example, an emulsion containing the first polymer elastic body such as polyurethane emulsion or acrylic emulsion is added to the web entangled sheet. A method of solidifying by impregnation and then drying is preferable.

  In addition, when a web entangled sheet is impregnated with an emulsion containing a general polymer elastic body and dried, the emulsion of the inner layer moves to the surface layer of the web entangled sheet as the drying of the emulsion proceeds from the surface, and the surface layer There is a tendency that a so-called migration phenomenon occurs, in which polymer elastic bodies are ubiquitous. When migration occurs, in the thickness direction of the web entangled sheet, the distribution of the polymer elastic body becomes non-uniform so that a large amount of the first polymer elastic body is exposed on the slice surface described later, There exists a tendency for the form stability of a sheet to fall. Generation | occurrence | production of such a migration is suppressed by using the emulsion of the polymeric elastic body which has heat-sensitive gelling property.

  When an emulsion containing a polymer elastic body has a heat-sensitive gelling property, a web entangled sheet is impregnated with the emulsion of a polymer elastic body having a heat-sensitive gelling property, and then hot air, steam, microwave, heat By treating with a water bath or the like, before the inner layer emulsion migrates to the surface layer of the web entangled sheet, the polymer elastic body is gelled or solidified by heat and fixed uniformly in the thickness direction.

  The emulsion of a polymer elastic body having heat-sensitive gelation properties is obtained by emulsifying a polymer elastic body using a nonionic surfactant having a low hydrophilic / lipophilic balance (HLB) as an emulsifier, or by heating a polymer elastic body with an emulsion. Is obtained by adding a heat-sensitive gelling agent that gels the emulsion. Specific examples of the heat-sensitive gelling agent include inorganic salts such as calcium chloride, polyethylene glycol type nonionic surfactant, polyvinyl methyl ether, polypropylene glycol, silicone polyether copolymer, polysiloxane and the like. These may be used alone or in combination of two or more.

  As described above, the web entangled sheet is impregnated with the first polymer elastic body by impregnating the web entangled sheet with an aqueous liquid such as an emulsion containing the first polymer elastic body and then drying. Can be granted. As a ratio of the first polymer elastic body impregnated in the web entangled sheet, the mass ratio of the solid content amount of the first polymer elastic body / the amount of ultrafine fibers formed is 5/95 to 30/70, Is preferably adjusted to a ratio of 10/90 to 20/80. If the ratio of the first polymer elastic body is too low, the fiber retainability when slicing the slice or the like is deteriorated, and the shape of the cross section is not stable, so that a smooth surface is less likely to be formed. There is. Further, when the ratio of the first polymer elastic body is too high, it is difficult to make the area ratio of the polymer elastic body occupying the exposed surface expressed by slicing or the like 20% or less, and the silver obtained Toned artificial leather has a rubber-like or resin-like texture peculiar to polymer elastic bodies, and it tends to be difficult to obtain a supple texture similar to high-quality natural leather.

  As the liquid containing the first polymer elastic body, an aqueous liquid such as the above-described aqueous emulsion is preferable because it does not use an organic solvent and has a small environmental load. Examples of the aqueous liquid of the first polymer elastic body include an aqueous emulsion of the polymer elastic body, an aqueous suspension of the polymer elastic body, and an aqueous solution in which the polymer elastic body is dissolved in an aqueous medium. Can be mentioned.

  The drying condition of the aqueous liquid containing the first polymer elastic body is not particularly limited as long as the first polymer elastic body is dried and solidified and sufficiently cured. For example, in the case of an aqueous emulsion, there may be mentioned conditions such as drying at a temperature of about 100 to 160 ° C. for 1 to 20 minutes.

  And, by selectively removing the sea component of the sea-island long fibers contained in the web entangled sheet impregnated with the first polymer elastic body obtained as described above, ultrafine fibers are obtained. .

  As a method for selectively removing the sea component, the first method is to use a solvent or a decomposing agent that does not dissolve and decompose the resin that forms the island component but selectively dissolves or decomposes only the resin that forms the sea component. A method of treating a web entangled sheet impregnated with a polymer elastic body is exemplified. Specifically, for example, when the resin that forms the island component is a polyamide-based resin or a polyester-based resin, and the resin that forms the sea component is a water-soluble PVA resin, hot water of 85 to 100 ° C. is used as the solvent. . In addition, when the resin that forms the island component is a polyamide-based resin or a polyester-based resin, and the resin that forms the sea component is an easily alkali-degradable modified polyester, an alkaline decomposing agent such as an aqueous sodium hydroxide solution is used as the decomposing agent. Used. Among these, in particular, a water-soluble PVA resin is used as the resin for the sea component, and the water component is treated by treatment in hot water at 85 to 100 ° C. for 100 to 600 seconds until the removal rate of the sea component reaches 95% by mass or more. It is preferable to extract and remove the conductive PVA resin. In this way, by converting the sea-island long fibers into ultrafine fibers, ultrafine fibers existing in a fiber bundle are formed. In addition, when processing with warm water, since generation | occurrence | production of the volatile substance which generate | occur | produces when using an organic solvent in the case of an extraction process is suppressed, environmental impact is low and it is preferable also on occupational health.

Thus, the intermediate | middle of the artificial leather base material containing the fiber entanglement of the fiber bundle of the fine fiber of average fineness 0.001-0.5 dtex, and the 1st polymer elastic body impregnated to the fiber entanglement A body sheet is formed. The average fineness of the ultrafine fibers in the formed intermediate sheet is 0.001 to 0.5 dtex, preferably 0.005 to 0.3 dtex, and more preferably 0.01 to 0.2 dtex. When the average fineness of the ultrafine fibers is less than 0.001 dtex, the mechanical properties of the silver-tone artificial leather obtained when the fiber strength becomes too low are lowered. On the other hand, if it exceeds 0.5 dtex, the fiber density cannot be increased because the fiber itself is bulky, and the sense of fullness of the resulting silver-tone artificial leather decreases. As the basis weight of the fiber-entangled body of ultrafine fibers of the intermediate in the sheet to be formed, it is preferably about 140~3000g / m ^2. The thickness of the intermediate sheet is not particularly limited, but specifically, for example, it is preferably 0.5 to 4.0 mm, and more preferably 0.8 to 3.0 mm.

  Next, the second step of performing the surface adjustment by adjusting the thickness by slicing or buffing the intermediate sheet will be described.

  In the second step, the intermediate sheet is sliced and divided into a surface substantially perpendicular to the thickness direction (a surface substantially parallel to the surface of the intermediate sheet). Alternatively, the thickness is adjusted by buffing. Specifically, in the case of slicing, for example, depending on the thickness of the intermediate sheet, for example, the band knife is about 0.2 to 2.0 mm, further about 0.4 to 1.5 mm per sheet. Slice into multiple pieces using a machine.

By adjusting the thickness of the intermediate sheet, an exposed surface such as a sliced surface is formed, and the cross section of the ultrafine fibers cut substantially parallel to the exposed surface is exposed. In the method for producing a silver-tone artificial leather according to the present embodiment, the cross-section of the ultrafine fibers is present so that the number density is 1000 pieces / mm ² or more, and the area ratio of the first polymer elastic body is an average. A silver layer is formed on the exposed surface adjusted to a ratio of 20% or less as described later.

On the exposed surface formed in this step, the cross section of the ultrafine fibers is 1000 / mm ² or more, preferably 2000 / mm ² or more, more preferably 3000 / mm ² or more. In this way, when there are many cross-sections of ultrafine fibers on the exposed surface, the number of ultrafine fibers supporting the silver surface layer formed on the surface increases, and the silver-tone artificial leather base with excellent peel strength A material is obtained. Since the fibers forming the cross section of such ultrafine fibers are continuously connected to the inside of the artificial leather substrate, the silver surface layer is supported more firmly than the ultrafine fibers lying on the surface. Therefore, the integrity of the artificial leather base material and the silver surface layer is enhanced, and only the silver surface layer is prevented from being lifted, and the occurrence of floating wrinkles due to the silver surface layer being lifted is suppressed. In addition, wear resistance is improved by the large number of ultrafine fibers entering the silver surface layer.

  The exposed surface formed in this step is characterized in that the area ratio of the first polymer elastic body is 20% or less, preferably 15% or less, more preferably 10% or less. Thus, since the area ratio of the first polymer elastic body exposed on the exposed surface is as small as 20% or less, even if it is a thin silver surface layer, for example, an adhesive that fixes the silver surface layer or the silver surface layer Ingredients can easily penetrate into the interior. And the ratio of the ultrafine fiber hold | gripped by the 2nd polymer elastic body which forms a silver surface layer at the time of formation of a silver surface layer becomes high. As a result, the peel strength is increased because the silver layer is firmly fixed by the anchor effect of the ultrafine fibers. On the other hand, since the surface layer of the exposed surface is not firmly fixed by the first polymer elastic body, it has a low resilience similar to the texture of natural leather with a high-class feeling, rather than the elastic texture unique to the polymer elastic body. A supple texture with a sense of fulfillment is obtained. When the area ratio of the first polymer elastic body exposed on the exposed surface exceeds 20%, the flexibility is lost, and the ratio of the fibers held by the silver surface layer when the silver surface layer is formed is low. Therefore, the peel strength decreases.

  The average raised length of the ultrafine fibers raised from the exposed surface is preferably 150 μm or less, more preferably 120 μm or less, and particularly preferably 100 μm or less on the exposed surface formed in this step. In such a case, the second polymer elastic body for forming the silver surface layer sufficiently grips the ultrafine fibers that lie on the exposed surface, and the peel strength tends to further improve. is there.

  In addition, when the ultrafine fibers form a fiber bundle, it is preferable to perform chamfering by buffing or the like so that the average length of the lying fiber bundle is 200 μm or less, and further 150 μm or less. The lying fiber bundle with an average length of more than 200 μm is part of the fiber entanglement, but not fully entangled. Accordingly, when the second polymer elastic body forming the silver surface layer is held by such a fiber bundle and fixed, the silver surface layer tends to float or peel easily. Therefore, by removing the lying fiber bundle having an average length exceeding 200 μm before forming the silver surface layer, the second polymer elastic body forming the silver surface layer is sufficiently intertwined. It becomes easier to grip the fiber. In addition, when a long fiber bundle lies on the surface of the artificial leather base material on which the silver surface layer is formed, the second polymer elastic body forming the silver surface layer is the artificial leather base material. There is also a tendency that the inside does not sufficiently penetrate. Therefore, by removing such a fiber bundle, the second polymer elastic body forming the silver layer easily penetrates into the artificial leather substrate.

  In addition, the artificial leather base material formed in this process is not only slicing for the purpose of thickness adjustment and surface smoothing, but also buffing using contact buffs and emery buffs, and if necessary, sag softening treatment Further, finishing treatment such as reverse seal brushing treatment, antifouling treatment, hydrophilization treatment, lubricant treatment, softener treatment, antioxidant treatment, ultraviolet absorber treatment, fluorescent agent treatment, flame retardant treatment, and the like may be performed. When the buffing treatment is performed, it is preferable to appropriately adjust the paper count, the number of rotations, and the like so that the average nap length of the exposed surface is 150 μm or less.

  Next, the third step of forming a silver surface layer containing the second polymer elastic body on the exposed surface formed by surface exposure will be described.

  In this step, a silver surface layer is formed on the exposed surface of the artificial leather base material by a silver surface layer forming method such as a dry surface forming method or a direct coating method. In the dry surface-forming method, after forming a silver surface coating containing a second polymer elastic body on a support substrate such as a release paper, an adhesive is applied to the surface of the silver surface coating, It is a method of forming a silver layer by sticking to the exit surface, pressing and adhering if necessary, and peeling the release paper. The direct coating method is a method in which a silver resin layer is formed by directly applying a liquid resin or a resin liquid containing a second polymer elastic body to the exposed surface, followed by curing.

  As the second polymer elastic body, a polymer elastic body conventionally used for forming a silver surface layer, such as the same type of polymer elastic body as listed in the first polymer elastic body described above. Can be used without any particular limitation.

  The thickness of the formed silver surface layer is not particularly limited, but is preferably about 300 μm or less, for example, because the balance between mechanical properties and texture can be maintained. In addition, according to the silver-tone artificial leather of this embodiment, since the high peeling strength of a silver surface layer can be maintained, a silver surface layer can also be finished thinly. Specifically, for example, even if a silver surface layer having a thickness of 150 μm or less, further 100 μm or less is formed, high peel strength and wear resistance can be maintained. In addition, by finishing the silver layer thinner, it is possible to obtain a silver-surface artificial leather base material that expresses a very fine natural leather-like fold. In addition, in the silver surface layer formed by the dry surface forming method, the thickness including the adhesive layer is defined as the thickness of the silver surface layer.

  Hereinafter, the present invention will be described more specifically with reference to examples. The scope of the present invention is not limited to these examples.

[Example 1]
Water-soluble thermoplastic PVA resin is used as the sea component, PET with an isophthalic acid modification degree of 6 mol% is used as the island component, the number of islands per fiber is 25, and the sea component / island component is 25/75 (weight) Ratio), a sea-island filament was discharged from the die at 260 ° C. Then, the ejector pressure was adjusted so that the spinning speed was 4000 m / min, and the sea-island long fibers having an average fineness of 2.5 dtex were collected on a net to obtain a long fiber web having a basis weight of 30 g / m ² .

And 12 sheets were piled up by carrying out cross wrapping of the obtained long fiber web, and the needle | hook breaking prevention oil agent was sprayed on this. The entangled long fiber web was obtained by needle punching with a punch density of 2000 punch / cm ² with a 6 barb needle.

  And the entangled long fiber web was heat-shrinked with water vapor. In the heat shrink treatment with water vapor, first, 30% by mass of water is given to the amount of sea components in the entangled long fiber web, and then a heated water vapor atmosphere with a relative humidity of 90% and a temperature of 110 ° C. Under heat treatment for 80 seconds. The area shrinkage rate at this time was 45%.

  Next, the web entangled sheet obtained by the heat shrink treatment was impregnated with anionic self-emulsifying aqueous polyurethane (100% modulus 3.0 MPa) and ammonium sulfate as a heat-sensitive gelling agent. The concentration of the aqueous polyurethane was adjusted so that the mass ratio of the solid content of the aqueous polyurethane / the amount of the island component was 15/85. In order to prevent migration, the aqueous polyurethane dispersion was subjected to gelation treatment in a water vapor atmosphere and then dried at 120 ° C. for 10 minutes.

  Then, the web entangled sheet impregnated with aqueous polyurethane is immersed in hot water at 95 ° C. for 10 minutes to remove sea components to form ultrafine fibers, and then dried at a temperature of 120 ° C. for 10 minutes. An intermediate sheet having a thickness of 2.1 mm was obtained. The amount of aqueous polyurethane in the intermediate sheet / mass ratio of ultrafine fibers was 14.6 / 85.4.

The obtained intermediate sheet was sliced along a plane parallel to the surface thereof to obtain an artificial leather substrate having a thickness of 1.0 mm and a basis weight of 525 g / cm ² . An example of the SEM photograph of the slice surface is shown in FIG. On the slice surface, an average of 3253 cross sections (A in FIG. 2) of ultrafine fibers was observed / mm ² , and an aqueous polyurethane (B in FIG. 2) was observed with an area ratio of 8.2%. Further, an average of 45 lying fiber bundles / mm ^{2 was} observed (C in FIG. 2), and the average length was 140 μm. Moreover, an example of the SEM photograph of the cross section of the thickness direction of an artificial leather base material is shown in FIG. The average napped length of the ultrafine fibers (D in FIG. 3) raised from the slice surface was about 50 μm. In addition, the number density of the cross section of the ultrafine fiber in the slice surface, the area ratio of the aqueous polyurethane, and the average napped length of the ultrafine fiber raised from the slice surface were measured by the following methods.

<Number density of cross section of ultrafine fiber on slice surface>
SEM photographs 200 to 300 times larger than the slice surface were taken, and the number of cross-sections of the ultrafine fibers observed in 10 uniformly selected 1 mm × 1 mm rectangular regions was counted. In addition, the ultrafine fibers that were raised and exposed to 200 μm or more on the surface were excluded from the count. The average value of the 10 points counted in this way was taken as the number density (pieces / mm ² ) of the fiber cross section.

<Area ratio of aqueous polyurethane on slice surface>
An SEM photograph of 100 times the slice surface was taken and printed. Then, in 10 rectangular areas of 1 mm × 1 mm that were selected uniformly, the part where the aqueous polyurethane was exposed on the surface was colored with a fluorescent pen, and the part was accurately cut out with a cutter, and the weight was measured. And the ratio of the area of the water-based polyurethane to the whole slice surface in the printed photograph was computed from the weight ratio. The average value of the 10 points calculated in this way was defined as the area ratio of the aqueous polyurethane in the projected plane of the slice plane.

<Average nap length of slice surface>
A 200 times SEM photograph of an arbitrary 10 cross section parallel to the thickness direction of the artificial leather substrate was taken. And the length from the slice surface of the ultra-fine fiber which is raising is measured, and the average value of 200 was made into the average raising length.

  Next, a silver surface layer was formed on the sliced surface of the obtained artificial leather base material by the dry surface forming method of the following process.

First, an aqueous polyurethane liquid for silver surface coating having the following composition was applied at 100 g / m ² on a release paper, and then dried at 90 ° C. for 1 minute and then at 120 ° C. for 2 minutes to obtain a thickness of 30 μm. An epidermal layer was formed.
(Aqueous polyurethane solution for silver surface coating)
Polycarbonate-based polyurethane (Hydran WLS-210 manufactured by DIC Corporation, solid content 35%): 100 parts by massCarbodiimide-based crosslinking agent (Hydran Assister CS-7 manufactured by DIC Corporation): 4 parts by mass Viscosity (Hydran Assister T-5 manufactured by DIC Corporation): 1.5 parts Brown pigment (Dilack Brown HS-8640 manufactured by DIC Corporation): 10 parts

Next, on the silver surface film formed on the release paper, an aqueous polyurethane liquid for adhesive layer having the composition shown below was applied at 150 g / m ² , and then dried at 90 ° C. for 3 minutes to obtain a thickness. A 60 μm adhesive layer was formed.
(Aqueous polyurethane liquid for adhesive layer)
Polycarbonate polyurethane (Hydran WLA-412 manufactured by DIC Corporation, solid content 45%): 100 parts by mass Thickener (Hydran Assister T-5 manufactured by DIC Corporation): 1.5 parts by mass Modified polyisocyanate crosslinking agent (Hydran Assist C-5 manufactured by DIC Corporation): 10 parts by mass

  A roll having a clearance of 70% of the thickness of the artificial leather base material, placed in such a manner that the adhesive layer side of the silver surface layer on the release paper is placed in contact with the slice surface of the artificial leather base material. Crimped. And after drying at 100 degreeC for 2 minute (s) and aging at 60 degreeC for 2 days, the silver-tone artificial leather was obtained by peeling a release paper. Then, the peel strength, abrasion resistance, flexibility, and generation of creases of the obtained silver-finished artificial leather were evaluated as follows.

<Peeling strength of silver layer>
A test piece was prepared by cutting the artificial leather with silver into 23 cm in the TD direction and 2.5 cm in the MD direction. Then, the adhesive was uniformly applied to a rubber plate having a width of 2.5 cm with the surface cut and heat-treated at 100 ° C. for 2 minutes, and then the silver surface layer side of the test piece was bonded together, and the pressure of ^{2 to 4} kgf / cm ² And then left at room temperature for one day. Then, the front end of the rubber plate to which the test piece is bonded is sandwiched between one chuck and the front end of the silver surface of the test piece is sandwiched between the other chuck, and pulled by a tensile tester at a speed of 100 mm / min. And the artificial leather substrate were peeled off. At this time, the average value of the flat portion of the obtained SS curve was obtained. A value obtained by converting an average value of three test pieces per 1 cm was defined as a peel strength of the silver layer.

<Abrasion resistance (Taber wear)>
A silver-tone artificial leather cut into a circle having a diameter of 13 cm was set on a turntable of a Taber abrasion tester (manufactured by TABER INSTRUMENT Corp). And it was made to wear 1000 times with two wear wheels (H-22 (manufactured by Daito Electron)). The load was set to 1 kg. And the abrasion loss of the silver-tone artificial leather at this time and the state change of the surface were determined. The surface state change was determined according to the following criteria.
First grade: No change in appearance Second grade: Silver surface coating is removed and the adhesive layer is exposed in less than half Grade 3: Silver surface coating is removed and the adhesive layer is exposed in more than half 4th grade: Artificial leather base material is exposed in less than half Grade 5: Artificial leather base material is exposed in more than half range

<Flexibility>
A test piece was prepared by cutting a silver-tone artificial leather into a square of 20 cm in length and 20 cm in width. Then, five panelists selected from those skilled in the art of artificial leather touched the test piece and judged flexibility according to the following criteria.
A: Like high-quality cowhide leather, there was no rebound when touched or bent, and the flexibility was high.
B: There was a standard flexibility to the extent that it could be used as a leather material used for sundries and the like.
C: Strong rebound and poor flexibility.

<Occurrence of creases>
A test piece cut into a square of 20 cm in length and 20 cm in width was visually observed for the shape of a crease generated when the surface was valley-folded so that the upper end and the lower end were combined in the vertical direction, and judged according to the following criteria.
A: A fine and uniform crease similar to that of high-grade cowhide leather was generated on the folded surface.
B: A general crease occurred in a leather material used for miscellaneous goods or the like occurred on the folded surface.
C: Rough creases such as a silver layer partially floating on the folded surface were generated.

  As a result of the evaluation, the peel strength of the silver layer of the obtained silver-tone artificial leather was 4.5 kg / cm, and the peel was caused by the breakage between the artificial leather substrate and the adhesive layer. Moreover, in the abrasion resistance evaluation by Taber abrasion, the abrasion loss was 10 g and the abrasion state was a 2nd grade. Furthermore, the occurrence of softness and creases were both judged as A. The results are shown in Table 1 below.

[Example 2]
An artificial leather substrate having a thickness of 1.0 mm and a weight per unit area of 450 g / cm ² is obtained by the same process and conditions as in Example 1 except that the punch density of needle punching is 650 punch / cm ² instead of 2000 punch / cm ^2. Obtained. The slice plane thus obtained artificial leather substrate, the cross section of the ultrafine fibers are averaged 1115 pieces / mm ² observed, also, an aqueous polyurethane was observed area ratio of 10.3%. Moreover, the average nap length of the ultrafine fibers raised from the slice surface was about 43 μm.

  And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

[Example 3]
In the same manner as in Example 1, an intermediate sheet was obtained and sliced. And the artificial leather base material having a thickness of 1.0 mm and a weight per unit area of 494 g / cm ^{2 according} to the same process and conditions as in Example 1 except that the sliced surface was further buffed to remove the lying fiber bundle. Got. An example of the SEM photograph of the slice surface is shown in FIG. The slice plane obtained artificial leather substrate in this manner, the cross section of the ultrafine fibers are averaged 3110 pieces / mm ² observed, also, an aqueous polyurethane was observed area ratio 8.5%. Moreover, the average nap length of the ultrafine fibers raised from the slice surface was about 60 μm. Further, lying average fiber bundles of 23 fibers / mm ^{2 were} observed, and the average length was about 100 μm. And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

[Example 4]
In the same manner as in Example 1, an intermediate sheet was obtained and sliced. Then, the slice surface was buffed to remove the lying fiber bundle, and further buffed to raise, and the thickness was 1.0 mm and the basis weight was 510 g according to the same process and conditions as in Example 1. An / cm ² artificial leather substrate was obtained. The slice plane obtained artificial leather substrate in this manner, the cross section of the ultrafine fibers are averaged 2844 pieces / mm ² observed, also, an aqueous polyurethane was observed area ratio 9.8%. Moreover, the average nap length of the ultrafine fibers raised from the sliced surface was about 147 μm. Further, the average lying fiber bundle was observed at 15 fibers / mm ² and the average length was about 90 μm. And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

[Example 5]
In the same manner as in Example 1, an intermediate sheet was obtained and sliced. Then, an artificial leather base material having a thickness of 1.0 mm and a basis weight of 534 g / cm ² was obtained by the same process and conditions as in Example 1 except that the sliced surface was further subjected to buffing treatment for raising. The slice plane obtained artificial leather substrate in this manner, the cross section of the ultrafine fibers are averaged 3049 pieces / mm ² observed, also, an aqueous polyurethane was observed area ratio of 8.8%. Moreover, the average nap length of the ultrafine fibers raised from the slice surface was about 253 μm. Further, an average of 42 lying fiber bundles / mm ^{2 was} observed, and the average length was about 130 μm. And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

[Comparative Example 1]
An artificial leather substrate having a thickness of 1.0 mm and a weight per unit area of 450 g / cm ² is obtained by the same process and conditions as in Example 1 except that the punch density of needle punching is set to 500 punch / cm ² instead of 2000 punch / cm ^2. Obtained. The slice plane thus obtained artificial leather substrate, the cross section of the ultrafine fibers are averaged 826 / mm ² observed, also, an aqueous polyurethane was observed area ratio 9.1%. Moreover, the average nap length of the ultrafine fibers raised from the slice surface was about 62 μm. And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

[Comparative Example 2]
Except for adjusting the concentration of the aqueous polyurethane emulsion impregnated in the web entangled sheet so that the mass ratio of the solid content of the aqueous polyurethane / the amount of the island component is 15/85. Obtained an artificial leather base material having a thickness of 1.0 mm and a basis weight of 589 g / cm ^{2 according} to the same steps and conditions as in Example 1. The slice plane obtained artificial leather substrate in this manner, the cross section of the ultrafine fibers are averaged 3447 pieces / mm ² observed, also, an aqueous polyurethane was observed area ratio 22.3%. Moreover, the average nap length of the ultrafine fibers raised from the slice surface was about 54 μm. And on the slice surface of the obtained artificial leather base material, a silver-faced artificial leather was obtained by forming a silver surface layer by the same process and conditions as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

  The silver-tone artificial leather of the present invention is preferably used as a skin material for men's shoes, sports shoes, bags, belts, camera cases, school bags, and the like. In particular, the silver-finished artificial leather of the present invention is excellent in peel strength and wear resistance, and thus is used for shoes that require high mechanical properties, particularly sports shoes. In addition, since it has a natural leather-like appearance and texture, it is preferably used for applications that require an excellent appearance, such as bag use and miscellaneous goods.

1 Artificial Leather Base 1a Extra Fine Fiber 2 Silver Surface Layer

Claims (8)

An artificial leather base material including a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement, and a surface of the artificial leather base A silver surface layer containing the second polymer elastic body formed in,
In the virtual cross section perpendicular to the thickness direction of the surface on the side in contact with the silver surface layer of the artificial leather substrate,
The number density of the cross-section of the ultrafine fibers is an average of 1000 / mm ² or more, and the area ratio of the first polymer elastic body exposed on the surface is an average of 20% or less. Toned artificial leather with silver. The ultrafine fibers form a fiber bundle;
2. The silver-finished artificial leather according to claim 1, wherein an average length of the lying fiber bundles of the fiber bundles observed in the virtual cross section is 200 μm or less. The artificial leather with silver tone according to claim 1 or 2, wherein the number density of the cross-section of the ultrafine fibers is an average of 3000 pieces / mm ² or more. An intermediate sheet of an artificial leather base material comprising a fiber entanglement of ultrafine fibers having an average fineness of 0.001 to 0.5 dtex and a first polymer elastic body impregnated in the fiber entanglement. One process,
A second step of chamfering by adjusting the thickness of the intermediate sheet;
A third step of forming a silver surface layer containing a second polymer elastic body on the exposed surface formed by the surface exposure,
In the observation surface when the exposed surface is observed with a scanning electron microscope,
The number density of the cross-section of the ultrafine fibers is adjusted to an average of 1000 / mm ² or more, and the area ratio of the first polymer elastic body is adjusted to an average of 20% or less. A method for producing silver-tone artificial leather. The ultrafine fibers form a fiber bundle;
5. The silver according to claim 4, wherein the second step includes a step of surface-exposing so that an average length of the lying fiber bundles is 200 μm or less among the fiber bundles observed on the observation surface. A method for producing toned artificial leather. The second step includes
The method includes a step of chamfering so that an average napped length of the ultrafine fibers raised from the exposed surface is 150 μm or less on an observation surface by a scanning electron microscope in a cross section parallel to the thickness direction of the artificial leather substrate. Item 6. A method for producing a silver-tone artificial leather according to Item 4 or 5. The first step is
Forming an ultrafine fiber generating fiber entanglement capable of forming the ultrafine fiber;
Impregnating the ultrafine fiber generating fiber entangled body with an emulsion of the first polymer elastic body having heat-sensitive gelation property, allowing the emulsion to gel, and drying;
Converting the ultrafine fiber-generating fiber entanglement into a fiber entanglement of ultrafine fibers,
The amount of the first polymer elastic body / the amount (mass ratio) of the ultrafine fibers is 5/95 to 30/70, The silver-tone artificial leather according to any one of claims 4 to 6 Production method. The third step is
It is the process of forming the said silver surface layer by laminating | stacking the silver surface skin layer film previously formed through the contact bonding layer on the said exposed surface, Silver tone of any one of Claims 4-7 Manufacturing method of artificial leather.