JP2018003191A - Sheet-like product and method for producing the same and grained artificial leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like product that is light-weight and that is excellent in peel strength of the sheet-like product and a resin layer when made into a grained artificial leather by forming the resin layer on a surface of the sheet-like product, and to provide a method for producing the same.SOLUTION: The sheet-like product comprises a fiber entangled body mainly formed of ultra fine fibers having an average single fiber diameter of 0.1-10 μm and an elastic polymer as components. The ultra fine fiber has hollow parts communicated with a fiber surface and existing in a fiber axis direction continuously. The ultra fine fiber has a hollowness of 20-70% in a cross section.SELECTED DRAWING: Figure 1

Description

  The present invention provides a sheet-like material that is lightweight and has excellent peel strength between the sheet-like material and the resin layer when a resin layer is formed on the surface of the sheet-like material to form an artificial leather with silver, a method for producing the same, and silver It is related with artificial leather.

  So-called artificial leather with silver, which is formed by coating or laminating a resin such as polyurethane on a fibrous base material, has characteristics such as excellent flexibility and mechanical properties not found in natural leather, It is used in a wide range of applications such as bags, belts, and school bags.

  In these applications, lightness is one of the important required characteristics, and various studies have been made to reduce the weight of the substrate. For example, in order to obtain a lightweight sheet-like substrate from a bulky nonwoven fabric, a method using a fiber structure formed from hollow fibers is known.

  Patent Document 1 proposes an artificial leather made of ultrafine fibers having a hollow portion of 0.1 to 8.0 denier obtained by direct spinning. Patent Document 2 proposes an artificial leather base that obtains hollow ultrafine fibers of 0.1 dtex or less from a sea-island type composite fiber having a core-sheath type island component. In either case, the artificial leather base is reduced in weight by applying hollow fibers.

Japanese Patent No. 3924360 Japanese Patent No. 4004938

  However, a resin layer is formed on the surface of the substrate in order to make the artificial leather with silver, but in order to strengthen the peel strength between the resin layer and the substrate, the amount of the resin layer applied is increased, and the resin enters the substrate. Since it is necessary to increase the amount, the light weight effect as an artificial leather with silver is diminished. That is, it is difficult to achieve both weight reduction of the artificial leather with silver and strong peel strength between the resin layer and the substrate.

  In view of the above-mentioned problems of the prior art, the present invention provides a sheet-like material that achieves both lightness and excellent peel strength between a substrate and a resin layer when made into artificial leather with silver, and a method for producing the same. It is.

  The sheet-like material of the present invention is a sheet-like material comprising a fiber entangled body mainly composed of ultrafine fibers having an average single fiber diameter of 0.1 to 10 μm and an elastic polymer as constituent components, wherein the ultrafine fibers are on the fiber surface. The sheet is characterized in that the communicating hollow portion is an ultrafine fiber continuously present in the fiber axis direction, and the hollow ratio is 20 to 70% in the cross section of the ultrafine fiber.

  According to the present invention, the resin layer is formed on the surface of the sheet-like material simultaneously with the light weight by applying to the sheet-like material the ultrafine hollow fiber in which the hollow portion communicating with the fiber surface continuously exists in the fiber axis direction. A sheet-like material that can simultaneously achieve high peel strength between the sheet-like material and the resin layer can be obtained.

Cross-sectional schematic diagram perpendicular to the fiber axis direction of the ultrafine fiber of the present invention

  The sheet-like material of the present invention is a sheet-like material comprising a fiber entangled body mainly composed of ultrafine fibers having an average single fiber diameter of 0.1 to 10 μm and an elastic polymer as constituent components, wherein the ultrafine fibers are on the fiber surface. The sheet is characterized in that the communicating hollow portion is an ultrafine fiber continuously present in the fiber axis direction, and the hollow ratio is 20 to 70% in the cross section of the ultrafine fiber.

  The ultrafine fibers forming the fiber entangled body constituting the sheet-like material of the present invention have an average single fiber diameter of 0.1 to 10 μm. By making the average single fiber diameter larger than 0.1 μm, sufficient mechanical strength can be imparted to the sheet-like material, and when the average single fiber diameter is less than 10 μm, the flexibility of the sheet-like material can be obtained. A more preferable range of the average single fiber diameter is 1 to 6 μm.

  Examples of the polymer constituting the ultrafine fiber include polyester, polyamide, polyolefin, acrylic, polyphenylene sulfide, and the like. Examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, potytrimethylene terephthalate, and polylactic acid. Examples of the polyamide include nylon 6, nylon 66, nylon 610, nylon 12, and the like. Examples of the polyolefin include polyethylene and polypropylene. In particular, from the viewpoint of weight reduction of the sheet-like material, polyamide and / or polyolefin having a small specific gravity of the polymer is preferable.

  The polymer may be obtained from recycled raw materials or plant-derived raw materials from the viewpoint of environmental considerations. The polymer may be copolymerized with other components and may contain additives such as particles, flame retardants and antistatic agents.

  The fiber entangled body mainly composed of the ultrafine fibers of the present invention is a nonwoven fabric and is produced by the following method. Short fiber nonwoven fabric obtained by forming a laminated web using a card or cross wrapper and then needle punching or water jet punching, long fiber nonwoven fabric obtained from spunbond method or melt blow method, and papermaking method The nonwoven fabric obtained by (1) can be adopted. Among these, short fiber nonwoven fabrics and spunbond nonwoven fabrics are preferably used because those having good thickness uniformity and the like can be obtained.

  The fiber length of the short fiber in the short fiber nonwoven fabric is preferably 25 to 90 mm. By setting the fiber length to 25 mm or more, a sheet-like material having excellent abrasion resistance can be obtained by entanglement. Moreover, the sheet-like material excellent in the compression characteristic of the sheet-like material can be obtained by setting the fiber length to 90 mm or less. The fiber length is more preferably 30 to 80 mm.

  In the non-woven fabric, not only the above-mentioned ultrafine fibers but also other polymer fibers can be mixed within a range not impairing the effects of the present invention. Examples of other polymer fibers to be mixed include fibers made of a thermoplastic resin such as polyester, polyamide, polyolefin, acrylic, and polyphenylene sulfide.

  The nonwoven fabric used in the present invention can be laminated with a woven fabric or a knitted fabric on the nonwoven fabric for the purpose of improving the strength. In the case where the nonwoven fabric and the woven or knitted fabric are laminated and integrated with a needle punch, in order to prevent damage to the fibers constituting the woven or knitted fabric by the needle punch, it is preferable that the yarn of the woven or knitted fabric is a strong twisted yarn. The twist number of the yarn constituting the woven or knitted fabric is preferably in the range of 700 T / m to 4500 T / m.

  The sheet-like material of the present invention comprises a fiber entangled body and an elastic polymer as constituent components. An elastic polymer refers to a polymer having rubber elasticity at room temperature. Due to the binder effect of the elastic polymer, it is possible not only to prevent the ultrafine fibers from falling out of the sheet-like material, but also to impart an appropriate cushioning property.

  Examples of elastic polymers include polyurethane elastomers, polyureas, polyacrylic acid, ethylene / vinyl acetate elastomers and acrylonitrile / butadiene elastomers and styrene / butadiene elastomers, polyvinyl alcohol, and polyethylene glycol. Is preferably a polyurethane elastomer. The elastic polymer can contain a plurality of elastic polymers.

  Examples of the polyurethane elastomer particularly preferably used in the present invention include polyurethane and polyurethane / polyurea elastomer.

  As the polyurethane elastomer used in the present invention, a polyurethane elastomer obtained by a reaction of a polymer diol, an organic diisocyanate and a chain extender is preferably used.

  As the polymer diol, for example, a polycarbonate diol, a polyester diol, a polyether diol, a silicone diol, and a fluorine diol can be employed, and a copolymer combining these can also be used. Among these, from the viewpoint of hydrolysis resistance, it is preferable to use a polycarbonate diol and a polyether diol.

  The polycarbonate-based diol can be produced by transesterification of alkylene glycol and carbonate, or reaction of phosgene or chloroformate with alkylene glycol.

  Examples of the alkylene glycol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and the like. Linear alkylene glycol, and branched alkylene glycols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol and 2-methyl-1,8-octanediol Alicyclic diols such as 1,4-cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylolpropane, and pentaerythritol. In the present invention, both polycarbonate-based diols obtained from individual alkylene glycols and copolymerized polycarbonate-based diols obtained from two or more types of alkylene glycols can be employed.

  Examples of the polyester diol include polyester diols obtained by condensing various low molecular weight polyols and polybasic acids.

  Examples of the low molecular weight polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-propane. Diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, and One kind or two or more kinds selected from cyclohexane-1,4-dimethanol can be used.

  Further, addition products obtained by adding various alkylene oxides to bisphenol A can also be used.

  Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro One kind or two or more kinds selected from isophthalic acid can be mentioned.

  Examples of the polyether-based diol used in the present invention include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols obtained by combining them.

  The number average molecular weight of the polymer diol is preferably in the range of 500 to 4000 when the molecular weight of the polyurethane-based elastomer is constant. By making the number average molecular weight preferably 500 or more, more preferably 1500 or more, it is possible to prevent the sheet-like material from becoming hard. Moreover, the intensity | strength as a polyurethane-type elastomer is maintainable by making a number average molecular weight into 4000 or less, More preferably, 3000 or less.

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

  As the chain extender, amine chain extenders such as ethylenediamine and methylenebisaniline, and diol chain extenders such as ethylene glycol can be preferably used. Moreover, the polyamine obtained by making polyisocyanate and water react can also be used as a chain extender.

  The elastic polymer used in the present invention may be used in combination with a crosslinking agent for the purpose of improving hydrolysis resistance and the like.

  In addition, the elastic polymer used in the present invention includes pigments such as carbon black, dyes, antioxidants, light-proofing agents, antistatic agents, dispersants, softeners, flame retardants, antibacterial agents, and deodorants as necessary. Such additives can be blended.

  It is preferable that the content rate of an elastic polymer is 5-200 mass% with respect to a fiber entanglement body. Depending on the content of the elastic polymer, the surface state, cushioning properties, hardness, strength, and the like of the sheet-like material can be adjusted. When the content is 5% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more, fiber dropping can be reduced. On the other hand, when the content is 200% by mass or less, more preferably 100% by mass or less, and still more preferably 80% by mass or less, a state in which ultrafine fibers are uniformly dispersed on the sheet surface can be obtained.

  As a cross-sectional shape perpendicular to the fiber axis direction of the ultrafine fiber in the present invention, a hollow portion communicating with the fiber surface continuously exists in the fiber axis direction. The continuity of the hollow portion is confirmed by performing cross-sectional observation of ultrafine (hollow) fibers extracted from the sheet-like material at a plurality of locations in the fiber axis direction. That is, the hollow portion is continuously present in the fiber axis direction, and the hollow portion is continuously communicated with the fiber surface in the fiber axis direction.

  This will be described with reference to FIG. The hollow portion Sb is a cross section perpendicular to the fiber axis direction of the ultrafine fiber, and the hollow fiber A can be closed by a tangent line B that closes one opening portion. In the enclosed area, that is, the area Sa surrounded by the thick line, the polymer constituting the ultrafine fiber excluding the hollow fiber A, that is, the area surrounded by the tangent and the inner peripheral portion of the fiber cross section. As a result, the weight of the sheet-like material is reduced and a resin layer is formed on the surface, and when the artificial leather with silver is formed, the resin of the resin layer enters the hollow portion from the opening, and the bonding area between the resin and the ultrafine fibers is increased. The peeling strength can be increased by the increasing anchor effect.

  The cross-sectional shape perpendicular to the fiber axis direction of the ultrafine fiber is sufficient if the hollow portion communicating with the fiber surface is continuously present in the fiber axis direction. For example, there are substantially C type, substantially U type, and substantially V type. Can be mentioned. The cross-sectional shape is not particularly limited as long as the hollowness described below is satisfied.

  The hollow ratio of the ultrafine fiber is 20 to 70%. Preferably it is 35 to 60%. If it is less than 20%, a sufficient anchoring effect cannot be obtained when the resin layer is formed, and a high peel strength cannot be obtained. If it exceeds 70%, the fiber shape cannot be maintained, and the hollow portion is crushed. Therefore, the bulky structure cannot be maintained, and the weight of the sheet-like material cannot be reduced.

  The method for measuring the hollowness is, for example, using a scanning electron microscope (VE-7800 manufactured by SEM KEYENCE) with a cross section (referred to as a fiber cross section) perpendicular to the fiber axis direction of the ultrafine fibers in the sheet-like material. Measured 30 single fibers randomly observed in a field of view of 30 μm × 30 μm at a magnification of 3000 ×, and as shown in FIG. 1, a tangent line B that closes the opening is drawn, and the tangent line and the fiber cross section Sb / Sa × 100 depending on the area ratio of the area surrounded by the outer contour, that is, the area of the region Sa surrounded by the thick line, and the area surrounded by the tangent and the inner periphery of the fiber cross section, that is, the area of the hollow portion Sb. (%).

  In the present invention, a nonwoven fabric formed by entanglement of a bundle of ultrafine fibers (ultrafine fiber bundle) is preferably used from the viewpoint of the strength of the sheet-like material.

  As a form of the ultrafine fiber bundle, the ultrafine fibers may be somewhat separated from each other, may be bonded or not bonded, may be partially bonded, and the ultrafine fibers are aggregated. It can also take forms.

The basis weight of the sheet-like material of the present invention is preferably in the range of 100 to 500 g / m ² . When the basis weight is preferably 100 g / m ² or more, more preferably 150 g / m ² or more, sufficient form stability and dimensional stability can be obtained for the sheet-like material. On the other hand, when the basis weight is preferably 500 g / m ² or less, more preferably 300 g / m ² or less, sufficient flexibility for the sheet-like material can be obtained.

  The thickness of the sheet-like material of the present invention is preferably in the range of 0.1 to 10 mm. By making the thickness preferably 0.1 mm or more, and preferably 0.3 mm or more, sufficient form stability and dimensional stability can be obtained. On the other hand, sufficient flexibility can be obtained by setting the thickness to preferably 10 mm or less, more preferably 5 mm or less.

  In the sheet-like material of the present invention, it is preferable that at least one surface is subjected to napping treatment. By the napping treatment, the thickness of the sheet-like material becomes uniform, and the resin can be uniformly applied or laminated when the resin layer is formed on the surface.

  The sheet-like material of the present invention may be used as artificial leather with silver by forming a resin layer made of a resin on one or both sides. That is, the artificial leather with silver of the present invention is characterized in that a resin layer is formed on at least one side of the sheet-like material of the present invention.

  Examples of the resin forming the resin layer include polyurethane, acrylic elastic body, silicone elastic body, diene elastic body, nitrile elastic body, fluorine elastic body, polystyrene elastic body, polyolefin elastic body, and polyamide system. Examples thereof include resin emulsions such as emulsions of elastomers such as elastic bodies, suspensions, dispersions or solutions. These may be used alone or in combination of two or more. Of these, polyurethane is preferred because of its excellent wear resistance and mechanical properties. The resin component may contain a colorant, an ultraviolet absorber, a surfactant, a flame retardant, an antioxidant, and the like as necessary.

  The resin layer may be either a foam layer or a dry layer made of an elastic polymer, or a combination of both.

  The thickness of the resin layer is preferably in the range of 0.03 to 3 mm. By setting the thickness to preferably 0.03 mm, more preferably 0.05 mm or more, sufficient wear resistance can be obtained for the artificial leather with silver. On the other hand, by setting the thickness to 3 mm or less, more preferably 0.5 mm or less, sufficient flexibility can be obtained for the artificial leather with silver.

  Moreover, it is preferable that the thickness of the artificial leather with silver after resin layer formation is the range of 0.2-12 mm, More preferably, it is the range of 0.4-5 mm.

  Next, the sheet-like material of the present invention and the manufacturing method thereof will be described.

  The hollow fiber of the present invention is preferably obtained from an ultrafine fiber expression type fiber, and more preferably obtained from a sea-island type composite fiber. The ultrafine hollow fiber used in the present invention has a sea component (easily soluble) inside the island component (slightly soluble) in the cross section perpendicular to the fiber axis direction of the sea-island composite fiber, and the inside and outside of the island component. It can be obtained by forming a composite fiber in which the sea components distributed in the sea are continuous, that is, a so-called Nakaumi-Irishima island-type composite fiber.

  By dissolving and removing the sea components of the Nakaumi-inland island type composite fiber with a solvent or the like, it is possible to obtain a hollow fiber in which hollow portions communicating with the fiber surface continuously exist in the fiber axis direction.

  Examples of the sea component of the sea-island fiber include polyethylene, polypropylene, polystyrene, copolymer polyester obtained by copolymerizing sodium sulfoisophthalate, polyethylene glycol, and the like, polylactic acid, and PVA.

  The fiber ultrafine treatment (sea removal treatment) of the sea-island fiber can be performed by immersing the sea-island fiber in a solvent and squeezing the solution. As the solvent for dissolving the sea component, when the sea component is polyethylene, polypropylene, or polystyrene, an organic solvent such as toluene or trichloroethylene is used. Further, when the sea component is a copolyester or polylactic acid, an alkaline aqueous solution such as sodium hydroxide or hot water is used.

  Since the ultrafine fiber of the present invention can be a hollow fiber in which hollow portions communicating with the fiber surface are continuously present in the fiber axis direction, the solvent during the fiber ultrafine treatment can easily dissolve sea components. When there is no hollow part communicating with the fiber surface, the solvent that dissolves the sea component dissolves the sea component only from the fiber cross section, so the longer the fiber length, the more difficult it is to dissolve the sea component in the hollow part. It takes time for the conversion process.

  For the fiber ultrafine treatment, apparatuses such as a continuous dyeing machine, a vibro-washer type seawater removal machine, a liquid dyeing machine, a Wins dyeing machine, and a jigger dyeing machine can be used.

  The sea component can be dissolved and removed at any timing before the impregnation with the elastic polymer, after the impregnation, and after the raising treatment. When the sea removal treatment is performed before the elastic polymer is applied, the elastic polymer is in close contact with the ultrafine fibers, and the ultrafine fibers can be strongly gripped, so that the wear resistance of the sheet-like material becomes better. On the other hand, when sea removal treatment is performed after applying an elastic polymer, voids are generated between the elastic polymer and the ultrafine fibers due to the sea component removed from the sea, so the ultrafine fibers are not directly held by the elastic polymer. In addition, the compression property of the sheet-like material is improved.

  The mass ratio of the sea component to the island component in the sea-island composite fiber used in the present invention is preferably in the range of sea component: island component = 10: 90 to 80:20. When the mass ratio of the sea component is less than 10% by mass, the island component is not sufficiently thinned. Further, when the mass ratio of the sea component exceeds 80 mass%, the productivity is lowered because the ratio of the eluted component is large. The mass ratio of the sea component and the island component is more preferably in the range of sea component: island component = 20: 80 to 70:30.

  In the present invention, when drawing an ultrafine fiber expression type fiber typified by a sea-island type composite fiber, after winding the undrawn yarn once, it is drawn separately, or the undrawn yarn is taken up and drawn continuously. Any method can be employed, such as. Stretching can be appropriately performed by a method of stretching by one to three stages by wet heat, dry heat, or both. Next, the stretched sea-island type composite fiber is preferably crimped and cut into a predetermined length to obtain a raw nonwoven fabric. A usual method can be used for crimping and cutting.

  The composite fiber used in the present invention is preferably given buckling crimp. This is because buckling crimps improve the entanglement between the fibers when a short fiber nonwoven fabric is formed, and enables high density and high entanglement. In order to impart buckling crimp to the composite fiber, a normal stuffing box type crimper is preferably used, but in order to obtain a preferable crimp retention coefficient in the present invention, the processing fineness, crimper temperature, crimper weight and It is a preferable aspect to adjust the indentation pressure and the like as appropriate.

The crimp retention coefficient of the ultrafine fiber-expressing fiber to which buckling crimp is imparted is preferably in the range of 3.5 to 15, more preferably in the range of 4 to 10. When the crimp retention coefficient is 3.5 or more, the rigidity in the thickness direction of the nonwoven fabric is improved when the nonwoven fabric is formed, and the entanglement property in the entanglement process such as needle punching can be maintained. Further, by setting the crimp retention coefficient to 15 or less, the fiber web is excellent in fiber opening in carding without excessive crimping.
The crimp retention coefficient here is expressed by the following equation.
- crimp retention factor ^{_{= (W / L-L 0}} ) 1/2
W: Crimp extinction load (load when crimp is fully extended: mg / dtex)
L: Fiber length under crimp extinction load (cm)
L ₀ : Fiber length (cm) under 6 mg / dtex. Mark 30.0 cm.

  As a measuring method, first, a load of 100 mg / dtex is applied to the sample, and then the load is increased in increments of 10 mg / dtex to confirm the state of crimping. A load is applied until the crimp is fully extended, and the length of the marking (elongation from 30.0 cm) in a state where the crimp is fully extended is measured.

  The single fiber fineness of the composite fiber used in the present invention is preferably in the range of 2 to 10 dtex, more preferably in the range of 3 to 9 dtex, from the viewpoint of entanglement such as a needle punching process.

  It is preferable that the shrinkage rate at a temperature of 98 ° C. is 5 to 40%, and more preferably 10 to 35% in the Nakaumi-inland island type composite fiber used in the sheet-like material of the present invention. By setting the shrinkage rate within this range, the fiber density can be improved by hot water treatment, and a sense of fulfillment like genuine leather can be obtained.

Specifically, the shrinkage rate is measured by first applying a load of 50 mg / dtex to a bundle of composite fibers and marking 30.0 cm (L ₀ ). Then, for 10 minutes in hot water at a temperature of 98 ° C., the length before and after processing _{(L 1)} was _measured, to calculate the _{(L 0 -L 1) / L} 0 × 100. The measurement is carried out three times, and the average value is taken as the shrinkage rate.

  In the present invention, the number of fibers in the ultrafine fiber bundle is preferably 8 to 1000 fibers / bundle, more preferably 10 to 800 fibers / bundle. When the number of fibers is less than 8 / bundle, the fineness of the ultrafine fibers is poor, and for example, mechanical properties such as wear tend to decrease. Further, when the number of fibers is more than 19000 / bundle, the spreadability at the time of napping is lowered, the fiber distribution on the napped surface becomes non-uniform, and the resin is formed when forming the resin layer on the surface of the sheet-like material. Cannot be applied or laminated uniformly.

  As a method of obtaining a nonwoven fabric which is a fiber entangled body constituting the sheet-like material of the present invention, a method of entanglement of a composite fiber web with a needle punch or a water jet punch, a spunbond method, a melt blow method, a paper making method, etc. are adopted Among them, a method of undergoing a treatment such as needle punching or water jet punching is preferably used in order to obtain the above-described ultrafine fiber bundle mode.

  As described above, the non-woven fabric may be formed by laminating and integrating the non-woven fabric and the woven or knitted fabric, and a method of integrating these by needle punch, water jet punch or the like is preferably used.

  In the needle used for the needle punching process, the number of needle barbs (cuts) is preferably 1 to 9. By using one or more needle barbs, efficient fiber entanglement becomes possible. On the other hand, by making the needle barb preferably 9 or less, fiber damage can be suppressed.

  The number of composite fibers such as ultrafine fiber-expressing fibers caught on the barb is determined by the shape of the barb and the diameter of the composite fiber. Therefore, the barb shape of the needle used in the needle punching process has a kick-up of 0-50 μm, an undercut angle of 0-40 °, a throat depth of 40-80 μm, and a throat length of 0.5. The thing of -1.0mm is used preferably.

Moreover, it is preferable that the number of punching is 1000-8000 / cm < ² >. By setting the number of punchings to preferably 1000 / cm ² or more, denseness can be obtained and high-precision finishing can be obtained. On the other hand, when the number of punching is preferably 8000 / cm ² or less, deterioration of workability, fiber damage, and strength reduction can be prevented.

  In addition, in the case of laminating and integrating a woven / knitted fabric and a nonwoven fabric composed of ultrafine fiber-expressing fibers, the barb direction of the needle of the needle punch is preferably 90 ± 25 ° which is perpendicular to the traveling direction of the woven / knitted fabric and the nonwoven fabric. This makes it difficult to hook easily damaged wefts.

  Moreover, when performing a water jet punch process, it is preferable to perform water in the state of a columnar flow. Specifically, it is a preferred embodiment that water is ejected from a nozzle having a diameter of 0.05 to 1.0 mm at a pressure of 1 to 60 MPa.

The apparent density of the nonwoven fabric composed of the composite fiber after the needle punching process or the water jet punching process is preferably 0.15 to 0.45 g / cm ³ . By making the apparent density preferably 0.15 g / cm ³ or more, the sheet-like product can have sufficient form stability and dimensional stability. On the other hand, when the apparent density is preferably 0.45 g / cm ³ or less, a sufficient space for applying the elastic polymer can be maintained.

  From the viewpoint of densification, it is preferable that the non-woven fabric made of the Nakaumi Ikumi-island type ultrafine fiber-expressing fiber thus obtained is contracted by dry heat or wet heat or both, and further densified. . In addition, the nonwoven fabric can be compressed in the thickness direction by calendaring or the like.

  In addition, in order to obtain denseness and uniformity of the fiber distribution on the surface of the sheet-like material, the elastic polymer is a fiber entanglement such as a nonwoven fabric in which a fiber bundle of ultrafine fibers is entangled. It is a preferred embodiment that it is not substantially present in. When the elastic polymer is present even inside the fiber bundle, the elastic polymer is present by adhering to each ultrafine fiber, so that the opening property during the buffing process is poor.

As a method of obtaining a form in which the elastic polymer does not substantially exist inside the fiber bundle of ultrafine fibers, for example, the elastic polymer is used as a solution,
(1) A fiber entangled body composed of ultra-fine fiber-expressing sea-island fibers is impregnated with the elastic polymer solution and solidified, and then the sea components of the sea-island fibers are dissolved in a solvent that does not dissolve the elastic polymer. How to dissolve and remove,
(2) A fiber entangled body composed of ultra-fine fiber-expressing sea-island fibers is provided with polyvinyl alcohol having a saponification degree of preferably 80% or more to protect most of the surroundings of the sea-island fibers. A method in which the sea component is dissolved and removed with a solvent that does not dissolve polyvinyl alcohol, and then the elastic polymer solution is impregnated and solidified, and then the polyvinyl alcohol is removed is preferably used.

  As the polyvinyl alcohol, polyvinyl alcohol having a saponification degree of 80% or more is preferably used.

  N, N-dimethylformamide, dimethyl sulfoxide, or the like is preferably used as a solvent used for imparting polyurethane as an elastic polymer, but it may be used as a water-dispersed polyurethane liquid in which polyurethane is dispersed as an emulsion in water. it can.

  In the case of using an organic solvent-based polyurethane, it can be coagulated by dry heat coagulation, wet coagulation, or a combination thereof, and wet coagulation in which the coagulation is performed by immersion in water is preferably used. By wet coagulation, the polyurethane does not concentrate at the entanglement point of the ultrafine fibers, and the polyurethane itself becomes porous. Therefore, the degree of freedom between the ultrafine fibers is increased, and a flexible sheet-like material can be obtained.

  The temperature of wet coagulation is not particularly limited.

  After the elastic polymer is applied to the fiber entangled body, dividing the obtained elastic polymer-added sheet-like material into half or several sheets in the sheet thickness direction is a preferable aspect with excellent production efficiency.

  The sheet-like material of the present invention may have napping on at least one surface of the sheet-like material.

  The raising treatment for forming the napped fibers of the ultrafine fibers on the surface of the sheet-like material of the present invention can be performed by a grinding method using a sandpaper or a roll sander. Before the raising treatment, a lubricant such as a silicone emulsion may be applied to the sheet.

  In addition, applying an antistatic agent before the above-mentioned raising treatment tends to make it difficult for the grinding powder generated from the sheet-like material to be deposited on the sandpaper by grinding.

  The sheet-like material can be dyed depending on the application. As a method for dyeing a sheet-like material, it is preferable to use a liquid dyeing machine because the sheet-like material can be softened by simultaneously giving a stagnation effect. If the dyeing temperature of the sheet-like material is too high, the polymer elastic body may be deteriorated. On the other hand, if it is too low, the dyeing to the fiber becomes insufficient. In general, the dyeing temperature is preferably 80 to 150 ° C, more preferably 110 to 130 ° C.

  The dye can be selected according to the type of fiber constituting the sheet-like material. For example, disperse dyes can be used for polyester fibers, acidic dyes or metal-containing dyes can be used for polyamide fibers, and combinations thereof can be used.

  Moreover, it is also a preferable aspect to use a dyeing assistant when dyeing the sheet-like material. By using a dyeing assistant, the uniformity and reproducibility of dyeing can be improved. In addition, a finishing treatment using a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, a light proofing agent, and an antibacterial agent can be performed in the same bath or after dyeing.

  Moreover, the resin layer which consists of resin may be formed in the sheet-like material of this invention, and you may use as artificial leather with silver. As a method for forming a resin layer, there are a method of directly coating a resin on a sheet-like material, and a dry surface forming method in which a resin film formed on a release paper is adhered to the surface of a sheet-like material via an adhesive layer. Although it is mentioned, it is also a preferable embodiment to form a laminated structure on the surface of the sheet-like material by combining these methods.

The resin coating amount of the resin layer is preferably in the range of 30 to 400 g / m ² , and more preferably in the range of 50 to 300 g / m ² . By setting it as the said range, the balance of a mechanical characteristic and a texture can be maintained.

  When the sheet-like material of the present invention is made of artificial leather with silver by forming a resin layer such as polyurethane on the surface, it is possible to achieve both strong and strong peeling strength between the sheet-like material and the resin layer, It is suitably used as shoes, bags, sports shoes, miscellaneous goods, clothing, and automobile interior materials. Further, the sheet-like material of the present invention can be dyed and processed as a suede-like artificial leather, taking advantage of flexibility and lightness.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited only to a following example.

[Measuring method and processing method for evaluation]
(1) Melting point of polymer:
The melting point of the polymer was determined by using a DSC-7 manufactured by Perkin Elmer Co., and the peak top temperature at which the polymer melted at 2nd run as the melting point of the polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg. The measurement was performed twice, and the average value was taken as the melting point.

(2) Average single fiber diameter of ultrafine fibers in the sheet-like material:
The average single fiber diameter was observed by a scanning electron microscope (VE-7800 manufactured by SEM KEYENCE) at a magnification of 3000 with a cross section perpendicular to the thickness direction of the nonwoven fabric containing ultrafine fibers, and was not observed within a 30 μm × 30 μm field of view. The diameters of 50 single fibers extracted randomly were measured. This was performed at three locations, the diameters of a total of 150 single fibers were measured, and the average value was calculated by rounding off the numbers after the decimal point. When the ultrafine fiber has an irregular cross section, first, the cross-sectional area of the single fiber was measured, and the diameter of the single fiber was calculated by calculating the diameter when the cross section was assumed to be circular.

(3) Hollow rate The hollow rate is 30 μm × 30 μm by observing a cross section perpendicular to the fiber axis direction in a sheet-like material at 3000 times using a scanning electron microscope (VE-7800 manufactured by SEM KEYENCE). 30 single fibers extracted at random within the field of view were measured. In the obtained cross-sectional photograph of the fiber, a tangent that closes the opening is drawn, the area Sa of the portion surrounded by the outer contour of the tangent and the fiber cross section, and the portion surrounded by the inner periphery of the tangent and the fiber cross section Was obtained as Sb / Sa × 100 (%) by the area ratio of the area Sb.

(4) Fabric weight of sheet-like material Measured by the method described in JIS L 1096 (1999) 8.4.2. A test piece of 20 cm × 20 cm to 5 sheets collected, weighed respective mass (g), representing the average value in 1 m ² per mass (g / ^{m 2).}

(5) Peel strength The peel strength of a silver-finished artificial leather in which a silver surface layer was formed on a sheet-like material was measured according to the measurement method defined in JIS K6854-2: 1999. A polyurethane crepe rubber plate (length: 150 mm, width: 27 mm, thickness: 5 mm) was used as the rigid adhesive material, and the flexible adhesive material was cut into three pieces each in the longitudinal and lateral directions. A silver-tone artificial leather having a thickness of 250 mm and a width of 25 mm was used. A test piece was prepared by adhering a silver-finished artificial leather and a rubber plate using a polyurethane-based two-part adhesive so that the adhesive force was sufficiently exhibited. The stress required when the test piece was peeled off at a speed of 50 mm / min and the peel length were measured to obtain a stress-peel length curve. The average peel strength was determined from the obtained curve. The average peel strength obtained for each of the longitudinal direction and the transverse direction was calculated by averaging. The peel strength was good at 100 N / cm or more.

[Example 1]
<Raw cotton>
(Island component polymer)
Polypropylene (PP) having a melting point of 160 ° C. was used.

(Sea component polymer)
Polystyrene (PSt) having a Vicat softening point of 100 ° C. measured according to JIS K7206 was used.

(Spinning / drawing)
Using the above-mentioned sea component polymer and island component polymer, a 14 island / hole sea-island type compound base capable of producing a sea-island composite section having an island component of approximately C-type, a spinning temperature of 285 ° C., island component / sea Melt spinning was performed under the conditions of a mass ratio of components of 44/56, a discharge rate of 1.2 g / min / hole, and a spinning speed of 1200 m / min.

  Next, the film was drawn in a drawing liquid bath at a temperature of 85 ° C. so that the magnification was 2.7 times, and crimped with a crimper to obtain a sea-island type composite fiber. The obtained sea-island type composite fiber had a single fiber fineness of 3.5 dtex and a shrinkage rate of 11.7% at a temperature of 98 ° C. This composite fiber was cut into a fiber length of 51 mm to obtain a raw cotton of sea-island type composite fiber.

<Nonwoven fabric>
Using the raw cotton, a laminated fiber web was formed through a card and a cross wrapper process. Next, the obtained laminated fiber web is subjected to needle punching with a punch number of 2700 / cm ² to produce a nonwoven fabric (fiber entangled body) having a basis weight of 750 g / m ² and an apparent density of 0.184 g / cm ^3. did. <Sheet>
After shrinking the nonwoven fabric with hot water at a temperature of 98 ° C., this was impregnated with an aqueous PVA (polyvinyl alcohol) solution to obtain a nonwoven fabric having a PVA mass of 51 mass% with respect to the mass of the nonwoven fabric. The nonwoven fabric obtained in this manner was immersed in trichlorethylene to dissolve and remove sea components to obtain a nonwoven fabric (sea removal sheet) made of ultrafine fibers.

  The nonwoven fabric (sea removal sheet) made of ultrafine fibers thus obtained was immersed in a DMF (dimethylformamide) solution of polycarbonate polyurethane as an elastic polymer, and then the polycarbonate polyurethane was coagulated in an aqueous solution. Thereafter, the PVA is removed by immersion in hot water and dried with hot air at a temperature of 110 ° C. for 10 minutes, whereby the nonwoven fabric (polyurethane-containing material) has a polyurethane mass of 59 mass% with respect to the mass of the ultrafine fibers made of island components. Sheet). Thereafter, the non-semi-finished surface of the polyurethane-containing sheet was ground using a JIS # 150 sandpaper to obtain a sheet.

<Artificial leather with silver>
Polyether-based polyurethane was coated with a knife coater on the surface of the sheet-like material that had been subjected to napping treatment so as to have a weight of 110 g / m ² and coagulated in an aqueous solution. Thereafter, a top layer (100 g / m ² ) made of polyether / polycarbonate polyurethane formed on the release paper was adhered to the outermost layer with an adhesive to obtain an artificial leather with silver.

The ultrafine fibers in the obtained artificial leather with silver had an average single fiber diameter of 4.4 μm and a hollow ratio of 45%. Further, the basis weight was 421 g / m ² , and the peel strength was 119 N / cm. The results are shown in Table 1.

[Example 2]
<Raw cotton>
(Island component polymer)
Nylon 6 (Ny) having a melting point of 220 ° C. was used as the island component polymer.

(Sea component polymer)
PET obtained by copolymerizing 8.5 mol% of sodium 5-sulfoisophthalate having a melting point of 240 ° C was used.

(Spinning / drawing)
A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the above sea component polymer and island component polymer were used. The obtained sea-island type composite fiber had a single fiber fineness of 3.6 dtex and a shrinkage rate of 12.4% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
The sheet-like material was treated in the same manner as in Example 1 except that the above-mentioned nonwoven fabric was used and the sea component was dissolved and removed using a 20 g / L sodium hydroxide aqueous solution heated to a temperature of 90 ° C. for 30 minutes. Obtained.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 45%. Further, the basis weight was 456 g / m ² , and the peel strength was 122 N / cm. The results are shown in Table 1.

[Example 3]
<Raw cotton>
(Island component polymer)
The same island component polymer as used in Example 2 was used.

(Sea component polymer)
The same sea component polymer used in Example 1 was used.

(Spinning / drawing)
A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the above sea component polymer and island component polymer were used. The obtained sea-island type composite fiber had a single fiber fineness of 3.6 dtex and a shrinkage rate of 13.0% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 45%. Further, the basis weight was 453 g / m ² , and the peel strength was 125 N / cm. The results are shown in Table 1.

[Example 4]
<Raw cotton>
(Island component polymer)
Polyethylene terephthalate (PET) having a melting point of 260 ° C. was used.

(Sea component polymer)
The same sea component polymer used in Example 1 was used.

(Spinning / drawing)
A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the above sea component polymer and island component polymer were used. The obtained sea-island type composite fiber had a single fiber fineness of 3.8 dtex and a shrinkage rate at a temperature of 98 ° C. of 14.0%.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 45%. Further, the basis weight was 481 g / m ² and the peel strength was 121 N / cm. The results are shown in Table 1.

[Example 5]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A sea-island composite fiber raw cotton was obtained in the same manner as in Example 1 except that the sea component polymer and island component polymer were used, and the discharge rate during spinning was 2.1 g / min / hole. The obtained sea-island type composite fiber had a single fiber fineness of 7.0 dtex and a shrinkage rate of 13.8% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 6.0 μm and a hollow ratio of 45%. The basis weight was 484 g / m ² and the peel strength was 110 N / cm. The results are shown in Table 1.

[Example 6]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the sea component polymer and the island component polymer were used and the mass ratio of the island component / the sea component was 67/33. The obtained sea-island type composite fiber had a single fiber fineness of 3.4 dtex and a shrinkage rate at a temperature of 98 ° C. of 12.2%.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the resulting silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollowness of 24%. The basis weight was 522 g / m ² and the peel strength was 108 N / cm. The results are shown in Table 1.

[Example 7]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A raw cotton of sea-island composite fibers was obtained in the same manner as in Example 1 except that the sea component polymer and the island component polymer were used, and the mass ratio of the island component / the sea component was 27/73. The obtained sea-island type composite fiber had a single fiber fineness of 4.2 dtex and a shrinkage rate of 16.3% at a temperature of 98 ° C.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 63%. Further, the basis weight was 467 / m ² and the peel strength was 113 N / cm. The results are shown in Table 1.

[Example 8]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A raw cotton of sea-island composite fibers was obtained in the same manner as in Example 1 except that the sea-island polymer and the island-component polymer were used and a 45-island / hole sea-island composite base was used. The obtained sea-island type composite fiber had a single fiber fineness of 3.9 dtex and a shrinkage rate of 14.3% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 2.5 μm and a hollow ratio of 45%. Further, the basis weight was 485 g / m ² , and the peel strength was 116 N / cm. The results are shown in Table 1.

[Comparative Example 1]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A sea-island composite fiber raw cotton was obtained in the same manner as in Example 1 except that the sea component polymer and the island component polymer were used and the mass ratio of the island component / the sea component was 78/22. The obtained sea-island type composite fiber had a single fiber fineness of 3.4 dtex and a shrinkage rate at a temperature of 98 ° C. of 10.2%.

<Nonwoven fabric>
Using the above raw cotton, processing was carried out in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 16%. Further, the basis weight was 545 g / m ² , the peel strength was 70 N / cm, and the anchor effect by the C-type fiber was not sufficiently obtained, and the peel strength was poor. The results are shown in Table 1.

[Comparative Example 2]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
Using the above-mentioned sea component polymer and island component polymer, a 14 island / hole sea-island type compound base capable of producing a core-sheath type sea-island composite cross-section having one middle sea component inside the island component is used. A raw material of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the mass ratio of the Nakaumi component / outside sea component was 39/27/34. The obtained sea-island type composite fiber had a single fiber fineness of 4.0 dtex and a shrinkage rate at a temperature of 98 ° C. of 15.3%.

<Nonwoven fabric>
Using the above raw cotton, processing was carried out in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 4.4 μm and a hollow ratio of 45%. The hollow portion was not in communication with the fiber surface. Further, since the basis weight was 489 g / m ² and the peel strength was 65 N / cm, which was a round fiber, the anchor effect was not obtained and the peel strength was poor. The results are shown in Table 1.

[Comparative Example 3]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
Using the sea component polymer and island component polymer described above, each island has 16 islands / hole sea-island type compound spinneret with no sea-sea component, and the island component / sea component mass ratio is 80. A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that it was set to / 20. The obtained sea-island type composite fiber had a single fiber fineness of 4.2 dtex and a shrinkage rate of 13.5% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was carried out in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the resulting silver-tone artificial leather had an average single fiber diameter of 4.4 μm. Further, the basis weight was 580 g / m ² , the peel strength was 59 N / cm, and the basis weight was high. Further, since the fiber was a round fiber having no hollow portion, the anchor effect was not obtained, and the peel strength was poor. The results are shown in Table 1.

[Comparative Example 4]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A sea-island composite fiber raw cotton was obtained in the same manner as in Example 1 except that a two-island / hole sea-island composite base capable of producing a sea-island composite cross section having an approximately C-shaped island component was used. The obtained sea-island type composite fiber had a single fiber fineness of 3.9 dtex and a shrinkage rate of 14.1% at a temperature of 98 ° C.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had an average single fiber diameter of 11.0 μm and a hollow ratio of 45%. Further, the basis weight was 496 g / m ² and the peel strength was 96 N / cm, which was poor. The results are shown in Table 1.

[Comparative Example 5]
<Raw cotton>
(Island component polymer and sea component polymer)
The same island component polymer and sea component polymer used in Example 1 were used.

(Spinning / drawing)
A raw cotton of sea-island type composite fiber was obtained in the same manner as in Example 1 except that the sea component polymer and island component polymer were used and the mass ratio of island component / sea component was 17/83 (hollow ratio 76). % Hollow fiber). The obtained sea-island type composite fiber had a single fiber fineness of 6.8 dtex, and a shrinkage at a temperature of 98 ° C. was 19.2%.

<Nonwoven fabric>
Using the above raw cotton, processing was performed in the same manner as in Example 1 to produce a nonwoven fabric.

<Sheet>
A sheet-like material was obtained in the same manner as in Example 1 except that the above nonwoven fabric was used. Due to the dissolution of the sea component, when immersed in the trichlorethylene solution and squeezed, the hollow crush of the substantially C-shaped cross-section fiber occurred, and the opening of the fiber cross-section was closed. That is, the hollow portion was not in communication with the fiber surface.

<Artificial leather with silver>
Except having used said sheet-like material, it carried out similarly to Example 1, and obtained the silver-tone artificial leather. The ultrafine fibers in the obtained silver-tone artificial leather had the openings in the fiber cross section closed due to the collapse of the hollow portions. The basis weight was 541 g / m ² , and the peel strength was 67 N / cm, which was poor. The results are shown in Table 1.

Sa: Area surrounded by thick line Sb: Hollow part A: Hollow fiber B: Tangent that closes the opening

Claims (4)

  In a sheet-like material comprising a fiber entangled body mainly composed of ultrafine fibers having an average single fiber diameter of 0.1 to 10 μm and an elastic polymer as constituent components, the hollow portion in which the ultrafine fibers communicate with the fiber surface has a fiber axis. A sheet-like product, which is an ultrafine fiber continuously present in a direction, and the hollowness of the ultrafine fiber is 20 to 70%.   2. The sheet-like product according to claim 1, wherein the ultrafine fibers are polyamide and / or polyolefin.   An artificial leather with silver, wherein a resin layer is formed on at least one surface of the sheet-like material according to claim 1 or 2. The method for producing a sheet-like material according to claim 1 or 2, wherein the ultrafine fiber is obtained from an ultrafine fiber-expressing fiber.

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