TWI447281B - Substrate for artificial leather and process for manufacturing it - Google Patents

Description

Substrate for artificial leather and preparation method thereof

The present invention relates to a substrate for artificial leather. When the base material for artificial leather is used, it is possible to produce a beautiful fluffy appearance having an extremely high density, and also excellent in color developability, excellent surface friction durability such as peeling resistance, and fluff having a soft and swellable texture. Artificial leather, or grain-like artificial leather with high smoothness and fine wrinkles, and high adhesion and peeling strength and soft and swellable texture.

Conventionally, on the surface of a substrate formed of a fiber bundle and a polymeric elastomer, a pile-like artificial leather such as a pile formed of the fiber bundle or a nappuck-like artificial leather such as a nubuck-like artificial leather is formed. Leather is known. Fluffy artificial leather, not only requires an appearance (closer to the surface texture of natural leather), texture (both soft touch feeling and appropriate expansion or fullness), colorimetry (color sharpness or concentration) and other sensibility In addition, the physical properties such as light resistance, peeling resistance, and abrasion resistance are required to meet the high standards, and various proposals for solving such problems have been made.

In order to satisfy the requirements of appearance or texture, for example, a method of forming ultrafine fibers using fibers constituting artificial leather is generally used. A method of producing artificial leather formed of ultrafine fibers is a method in which a composite fiber such as an island-in-season or a multi-layer bonding type is divided, or a component is removed by decomposition or extraction to form an ultrafine fiber bundle. In the non-woven fabric formed of the ultrafine fiber bundle obtained from the conjugate fiber, the artificial leather or the grain-like artificial leather of the base material for artificial leather containing the polymer elastic body is used. Or the texture is very high. However, when the fineness is refined, there is a disadvantage that the color developability is lowered and the sharpness or the concentration feeling is remarkably deteriorated, and in particular, in the case of the fluffy artificial leather, all the high quality requirements cannot be satisfied.

In the method of producing a nonwoven fabric structure for use in a base material for artificial leather, generally, the spun fiber is formed into a short fiber having a length of 100 mm or less, and the object is formed into a desired unit by a stencil method or a papermaking method. The area-weight non-woven web, which is required to have a plurality of sheets of the nonwoven web, is most commonly used by a needle punching method or a non-woven method to complex the fibers. A nonwoven fabric structure having a desired bulkiness or degree of complexation is produced by such a method, and a substrate for artificial leather is produced. The use of the fluff-like artificial leather or the grain-like artificial leather of the base material for artificial leather can be evaluated particularly in terms of texture. However, the short fibers constituting the non-woven fabric structure are fixed in the substrate by the complexation treatment between the fibers or the polymer elastomer contained therein, but with the fluffy surface of the fluffy artificial leather or the grain of the artificial leather of the grain-like artificial leather. At the bonding interface of the layer, since the fiber length is short, the tendency to easily pull off or fall off the non-woven fabric structure cannot be avoided. By this tendency, there is a case where the important surface physical properties such as the rubbing durability of the pile surface or the adhesion peeling strength of the grain layer are lowered. In order to solve this problem, in general, for example, in order to increase the degree of complexation of the nonwoven fabric structure, to bond the fibers, or to strengthen the restraint between the fibers, a method comprising a large amount of the polymer elastomer is employed. However, when the degree of complexation is increased and the content of the polymeric elastomer is increased, the texture of the artificial leather is remarkably deteriorated, and the appearance, texture, and surface physical properties cannot be satisfied at the same time.

Code for improving the peeling resistance of fluff fibers of fluffy artificial leather For the surface friction durability, for example, it is proposed to impregnate a polyvinyl alcohol (hereinafter abbreviated as PVA) by a needle-punched nonwoven fabric formed of a sea-island type fiber which is formed of an ultrafine fiber bundle formed of ultrafine fibers of 0.8 denier or less. The aqueous solution is dried and fixed to pseudo-fix the shape of the non-woven fabric; the organic component dissolved in the sea-island component of the sea-island type fiber is extracted to remove sea components; and the urethane-containing dimethylformamide is impregnated ( Hereinafter, the solution is solidified by a solution of DMF); then, the fluff-like artificial leather obtained by raising the surface (see Patent Document 1). It is proposed to have a diameter larger than one-fourth of the fiber diameter in the ultrafine fibers, and to add inert coarse particles to the fibers.

In Patent Document 2, a leather base is obtained by impregnating a DMF solution of a polyurethane in a needle-punched nonwoven fabric formed of sea-island type fibers, and then solidifying the sea component. The material is raised to produce fluffy artificial leather. The fiber bundle constituting the substrate is an ultrafine fiber of fine fibers (A) of 0.02 to 0.2 denier and fineness of less than 1/5 of the average fineness of the fine fibers (A) and less than 0.02 denier ( B) is formed, and the ratio of the number of the pieces (A/B) is 2/1 to 2/3. The polymer elastic body is substantially not contained in the inside of the fiber bundle, and the ratio (A/B) of the fine fibers (A) to the ultrafine fibers (B) in the pile fibers is 3/1 or more.

In addition, a method of dissolving a polymer elastomer in which a solvent is present in the root portion of the pile fiber and fixing the root portion of the pile fiber to improve the peeling resistance of the pile artificial leather has been proposed (see Patent Document 3).

In Patent Document 4, when a long-fiber non-woven fabric of fluffy artificial leather which can be converted into an extremely fine surface touch feeling is proposed, when the needle is treated by the needling treatment, the long fibers are actively cut off on the surface of the non-woven fabric. It was found that the cut ends of the fibers of 5 to 100/mm ² were subjected to the complexation treatment in the long-fiber non-woven fabric to solve the deformation problem. Further, in any cross section parallel to the thickness direction of the non-woven fabric, there are 5 to 70 fiber bundles per 1 cm width (in other words, in any cross section parallel to the thickness direction of the non-woven fabric, by needle punching in thickness) The direction-aligned fibers have a range of 5 to 70 in a width of 1 cm, and the total area occupied by the fiber bundles is in a range of 5 to 70% of the cross-sectional area on any cross section perpendicular to the thickness of the nonwoven fabric.

Patent Document 5 proposes a long fiber which can be converted into an ultrafine fiber of 0.5 denier or less, the long fiber has a crimp of 10% or less, and the non-woven fabric has a fiber density of 0.25 to 0.50 g/cm ^{3 .} The long fiber is woven with non-woven fabric.

However, in the method described in Patent Document 1, since the sea component of the sea-island type fiber is extracted and removed, the DMF solution of the polyurethane is subjected to impregnation and solidification treatment, and the polyurethane invades the ultrafine fiber bundle. Internally, texture hardening cannot be avoided. Further, since coarse particles are added to the fibers, a soft texture or a hand touch feeling cannot be obtained.

In the method described in Patent Document 2, since the DMF solution of the polyurethane is impregnated and solidified before the sea component of the sea-island type fiber is extracted and removed, substantially no polyamine is present in the outer portion and the inner portion of the ultrafine fiber bundle. Under the carbamate, a soft texture or a hand touch can be obtained. However, since the ultrafine fiber bundle is not fixed by the polyurethane, the peeling resistance is insufficient.

According to the method described in Patent Document 3, since only a part of the polymeric elastomer present on the outermost surface of the substrate such as leather is dissolved, only the fluff fibers are used. The root portion is fixed, and the fixing effect of the fiber inside the leather substrate is lacking, and the fixing ability to the polymer elastic body of the fiber is low, and the fiber having a denier resistance of 0.01 denier or more cannot be improved.

Patent Document 4 is a method for producing a long-fiber non-woven fabric structure, and has a cut end portion without lowering the physical properties as much as possible below the target level. However, the practical problem is that since a considerable amount of long fibers are cut, the fiber continuity due to the advantage of the long fibers causes the effect of improving the strength of the nonwoven fabric to be lowered, and the characteristics of the long fibers cannot be sufficiently produced. Further, in the complexation treatment of Patent Document 4, it is not necessary to form the long fibers from the surface of the long-fiber non-woven fabric through the inside and the opposite surface, and the long fibers are not cut over the surface to form 5 to 100 pieces. A very large number of cut ends of /mm ² are performed. Therefore, when a general complexing treatment is used, the needling treatment must be carried out under relatively strong conditions, and not only the fibers are difficult to be complexed, but most of the fibers which are originally long fibers are changed into short fibers, and the non-woven fabric is formed into long fibers. Directly to the different states of the complex, the result is easy to become close to the texture of artificial leather obtained from the conventional short fiber non-woven fabric. The quality is not easy to produce the high quality artificial leather for the purpose of the present invention.

In the method described in Patent Document 5, when only the value of the fiber density is observed, a long-fiber non-woven fabric having high denseness can be obtained. However, since the densification method is only a needle punching treatment and a pressing treatment, the obtained nonwoven fabric structure is only scattered. A high-quality artificial leather for the purpose of the present invention cannot be obtained with a gap of about 100 μm to a few hundred μm. More specifically, depending on the fiber diameter or the needling condition, the non-woven structure after the needling treatment essentially has a gap of about several hundred μm to a few mm, and then one of the fibers is thermally softened. When it is processed and pressed in the thickness direction, the sea component is simultaneously hardened in a state where the thickness direction is collapsed, and only the shape is fixed, and the void itself remains directly. Therefore, since the size of the collapsed voids is restored to the original size by the sea component when the sea component is removed, a structure having a gap of about 100 μm to several hundreds μm is formed.

JP-A-53-34903 (p. 3 to 4) Patent Document 2: JP-A-7-173778 (pages 1 to 2) Patent Document 3: JP-A-57-154468 Japanese Laid-Open Patent Publication No. 2000-273769 (pages 3 to 5) Patent Document 5: Japanese Patent Laid-Open No. Hei 11-200219 (pages 2 to 3)

In the past, the fluffy artificial leather could not have both a beautiful, dense fluffy feel and the color development of the ultrafine fiber fluff; a soft feeling of expansion and fullness; a soft surface feel of the fine fiber fluff and a typical surface friction of peeling resistance Durability, etc. In the grain-like artificial leather, it is not possible to balance the balance between the granule portion and the base portion, for example, the smoothness is high, the hard wrinkles are hard, and the softness of the base material portion is soft. The balance of the nature; the texture of the grain surface and the base portion with a soft feeling of expansion and fullness; the high flexibility of the base portion, the soft texture, and the adhesion to the grain-substrate interface Typical surface mechanical properties and so on.

The present invention provides a base material for artificial leather, which is a performance of a sensory surface having a high level and a conventionally opposite performance, and a property of a physical surface. By using the substrate of the present invention, it is possible to obtain an artificial leather having both high quality and high physical properties which are not conventionally known.

In order to achieve the above problems, the inventors of the present invention have further studied the results of the review and completed the present invention. In other words, the present invention relates to a substrate for artificial leather, which satisfies the following (1) to (4): (1) extremely elongated fiber bundles, so that 8 to 70 bundles of extremely thin fibers having a cross-sectional shape of about circular shape are bundled. (2) The extremely long fiber bundle has a cross-sectional area of 170 to 700 μm ² and an aspect ratio of 4.0 or less. (3) In any cross section parallel to the thickness direction of the nonwoven fabric structure, the cross section of the extremely elongated fiber bundle is 1,500 to 3,000. The range of /mm ² is present, and (4) the void size between the ultrafine fiber bundles is 70 μm or less in any cross section parallel to the thickness direction of the nonwoven fabric structure.

Further, the present invention relates to a method for producing a substrate for artificial leather, which comprises the following steps (a) to (d), (a) using a heat-shrinkable polymer for an island component and a water-soluble polymer for a sea component; The island-type long fiber with a ratio of 8 to 70 islands, a sea-island cross-sectional area of 5:95 to 60:40, and a cross-sectional area of 70 to 350 μm ² is melt-spun, so that the object is not cut. Breaking, gathering in a random alignment state on the collecting surface to produce a sheet-like long-fiber web, (b) making the long-fiber web as many overlapping combinations as needed, using at least 6 needles a step of manufacturing a non-woven fabric structure by performing needle punching on both sides and causing the island-in-the-sea long fibers to be three-dimensionally coupled to each other under the condition that at least one of the knitting needles is penetrated and the needles of the knitting needle are penetrated. (c) The non-woven fabric structure is subjected to a wet heat treatment under the condition that the sea component polymer is plasticized and the island component polymer is shrunk, and is subjected to hot pressing treatment as required, and is made in a cross section parallel to the thickness direction. The cross section of the island-type long fiber is in the range of 1000 to 3500 pieces/mm ² The densification step, (d) the step of removing the sea component from the sea-island type long fiber by water or an aqueous solution to become a very elongated fiber bundle.

In the base material for artificial leather of the present invention, since the ultrafine cellulose is aggregated into a dense state which is not conventionally known, a surface state which is extremely dense and excellent in smoothness can be obtained. When the base material for artificial leather of the present invention is used, surface friction which is superior to natural leather and has a smooth and elegant appearance or touch feeling without deterioration, color developability, texture with a feeling of expansion, and peeling resistance can be obtained. Fluffy artificial leather with excellent durability. Further, it is possible to obtain a grain-like artificial leather which is superior to the natural leather and which has a texture which is not deteriorated, smooth and soft, and has excellent surface strength such as texture and adhesion peeling strength.

[Best Mode for Carrying Out the Invention]

The substrate for artificial leather of the present invention can be obtained, for example, by sequentially performing the following steps (a) to (d).

Step (a) The island component is made of a heat-shrinkable polymer, and the sea component is a water-soluble polymer, and the sea component polymer and the island component polymer are extruded from a nozzle for composite spinning, and the sea-island type long fiber is subjected to melt spinning treatment.

In the nozzle for a composite spinning, a nozzle hole having a cross-sectional state in an arbitrary number of ranges of 8 to 70 in which the island component polymer is dispersed in the sea component polymer is arranged in a plurality of linear parallel rows and columns. Constructor Preferably.

In the obtained fiber cross section, the relative supply of the sea component polymer and the island component polymer is adjusted at an arbitrary ratio of the area ratio (ie, the polymer volume ratio) in the range of sea/island = 5/95 to 60/40. The amount or supply pressure is discharged from the nozzle in a molten state under a temperature condition in which the nozzle temperature is any temperature within a temperature range of 180 to 350 °C.

The cross-sectional area of the obtained island-type long fiber is any value in the range of 70 to 350 μm ² , and the single-denier degree, for example, the island component polymer is polyethylene terephthalate, and the sea component polymer is water-soluble thermoplastic polyvinyl alcohol. In view of the ratio of the area of the composite polymer, any value in the range of 0.9 to 4.9 dtex is preferable, and more preferably any value in the range of 1.9 to 3.9 dtex.

In the case of the island-type long fibers which have been melted and spun, the surface area of the mesh is formed by laminating in a random alignment state, and the desired area weight (preferably 10 to 1000 g/m ² ) is produced. Long fiber web.

Step (b), using the cross-layer laminate or the like as the above-mentioned long-fiber fiber web, and using a cross stitch in a thickness direction, at least six needles are used, and at least one of the needles is used. The needle hook is under the condition of penetration, and the needle-punching treatment is performed simultaneously or alternately from both sides, so that the fiber is three-dimensionally complexed, and the island-type long fiber is 400-2000/mm ^{2 in} the cross section parallel to the thickness direction. Any density within the range exists to produce an extremely dense, assembled nonwoven structure of island-type long fibers. The long-fiber fiber web can be used to impart oil or anti-static effect alone or to control the oil resistance of the needle and to control the friction between the fibers at any stage after the production and until the complex treatment. Oil agent when resisting.

Step (c) The non-woven fabric obtained by the step (b) is subjected to a wet heat treatment under the condition that the sea component polymer is plasticized and the island component polymer is shrunk, and additional hot pressing treatment is performed as needed. The cross section of the island-in-the-sea long fibers is dense and gathered in a range of 1000 to 3,500 / mm ² in a cross section parallel to the thickness direction. The above-mentioned wet heat treatment is, for example, a method of introducing an environment in which saturated steam is continuously supplied; and the sea component polymer is allowed to expand to the nonwoven fabric structure until it is desired. After a sufficient amount of water in the plasticizing treatment, a method of heating the moisture in the nonwoven fabric structure by heating electromagnetic waves such as gas or infrared rays, or a method of combining the same may be employed. In addition to the effect of densifying the fiber structure, the above-mentioned hot press treatment is expected to have an effect of fixing the form of the nonwoven fabric structure or to smooth the surface.

The average apparent density of the nonwoven fabric structure after the densification treatment in the step (c), for example, when the island component polymer is polyethylene terephthalate or the sea component polymer is water-soluble thermoplastic polyvinyl alcohol, Any value in the range of 0.3 to 0.8 g/cm ³ is preferred. Moreover, the average apparent density is obtained by a method of not applying a compressive load, for example, by a cross-sectional observation method by an electron microscope or the like. The basis weight of the nonwoven fabric structure is usually preferably from 100 to 2,000 g/cm ³ .

Step (d) (d) The sea component polymer is extracted from the sea-island type long fibers constituting the nonwoven fabric structure by water or an aqueous solution to become a very elongated fiber bundle.

According to the substrate for artificial leather obtained as described above, the effects of the present invention can be obtained by sequentially performing the following steps (e) to (h), and are more suitable for having a wool-like, nubuck leather A base material for artificial leather such as a natural leather such as a fluffy artificial leather having no deteriorated appearance or a touch feeling.

Engineering (e) A solution, an aqueous dispersion or a melt of an extractable polymer is applied to at least one side of the nonwoven structure, and the extractable polymer is subjected to a curing treatment.

Step (f) An aqueous dispersion of a polymeric elastomer is applied to the same surface to cure the polymeric elastomer.

Step (g) The easily extractable polymer is removed from the non-woven structure.

Step (h) The surface of the polymer elastic body is applied by pressing and polishing, and the surface gap size between the ultrafine fiber bundles is set to 200 μm from the surface of the polishing treatment side of any cross section parallel to the thickness direction of the nonwoven fabric structure. Densification is carried out in the range of 10 to 40 μm.

Further, in the above method for producing a substrate for artificial leather, the present invention can be obtained by performing the following step (i) as needed before the step (d) or after the step (d) is carried out The effect is more suitable for a base material for artificial leather of a grain-like artificial leather excellent in texture such as a feeling of one of the coating layers.

Step (i) a solution or water dispersion of a polymer elastomer in a non-woven structure The liquid and the polymer elastomer are hardened.

In the following, the method for achieving the present invention will be described in more detail.

The sea-island type fiber constituting the nonwoven fabric structure of the present invention is a multi-component yarn composite fiber formed of at least two types of polymers, and is distributed in a sea component polymer mainly composed of a fiber outer peripheral portion in a fiber cross section. A fiber having a cross-sectional morphology of a different type of island component polymer. The island component polymer of the present invention is distributed in a circular cross-sectional shape by the action of surface tension and the ratio of the sea component polymer to the island component polymer. Further, the term "circular" as used herein refers to a shape such as a character or a nearly circular shape, and refers to a polygonal shape or an elliptical shape which is close to a circle. The sea-island type fiber can be extracted or decomposed by the sea component polymer at a suitable stage before or after the treatment by forming a non-woven fabric structure having a desired density and then considering the desired impregnated polymer elastomer. By removing it, it is possible to produce a fiber bundle in which a plurality of fibers which are formed of a residual island component polymer and which are thinner than the original sea-island type fibers are bundled. The sea-island type fiber can be produced by a conventional spinning method (mixed spinning) method or a spinning method of a typical multi-component yarn composite fiber of a composite spinning method. In the sea-island type fiber, the sea-component polymer in the fiber cross-section is mainly composed of the outer peripheral portion of the fiber, and when the outer peripheral portion of the fiber is formed by a plurality of components, which are formed by a petal shape or an overlapping shape, and the like, The needling treatment is such that cracking, bending, cutting, etc., which are caused by typical fiber complexing treatment, are extremely rare, and the degree of densification can be further improved by the complexing treatment. Further, when the sea-island type fiber is compared with the peel-off type composite fiber, since the anisotropy in the in-plane direction perpendicular to the fiber axis is small, each of the ultrafine fibers can be obtained. When the ultrafine fiber bundle having a fineness, that is, a high uniformity of the cross-sectional area, is a non-woven fabric structure, a very large number of fiber bundles can be collected with a density which is not conventionally known. Therefore, the nonwoven fabric structure of the present invention is produced by using sea-island type fibers when these effects are obtained in a peeling-separated type composite fiber which does not have a petal shape or an overlapping shape.

The polymer constituting the island-type fiber island component and the heat-shrinkable polymer are important. For example, polyethylene terephthalate (hereinafter abbreviated as PET), polypropylene terephthalate (hereinafter referred to as PTT), polybutylene terephthalate (hereinafter referred to as PBT), polyester elasticity Polyester-based resin such as a body or a modified product thereof; each of heat-shrinkable polymerization having a conventional fiber forming ability, such as a heat-shrinkable polyamine-based resin, a heat-shrinkable polyolefin-based resin, or the like Things. Among these, by using PET, PTT, PBT, or a polyester-based resin such as such a modified polyester, it is possible to obtain a dense fiber bundle which is obtained by heat shrinkage and which is densely packed for the purpose of the present invention. The base material for artificial leather formed by the nonwoven fabric structure can be characterized by having an inductive surface such as a dense surface feeling and a feeling of fullness, or a practical property such as abrasion resistance, light resistance, or form stability. Better for leather goods. The island component polymer preferably has a melting point (hereinafter abbreviated as Tm) of 160 ° C or higher, and a fiber-forming crystalline resin having a Tm of 180 to 330 ° C. When the Tm of the island component polymer is lower than 160 ° C, the form stability of the obtained ultrafine fibers cannot reach the level of the object of the present invention, and in particular, the practical properties of the artificial leather product are not good. In the present invention, the Tm system uses a differential scanning calorimeter (hereinafter abbreviated as DSC), and in a nitrogen gas atmosphere, at a temperature rising rate of 10 ° C / min, from room temperature, and depending on the required temperature to 300 to 350 ° C, Then cooling The peak top temperature of the endothermic peak of the polymer observed at room temperature and at a temperature increase rate of 10 ° C /min and a temperature increase of 300 to 350 ° C. In the present invention, a colorant, an ultraviolet absorber, a heat stabilizer, a deodorant, an antifungal agent, and other various stabilizers of an antibacterial agent may be added to the polymer constituting the ultrafine fibers.

The polymer constituting the sea component of the island-type fiber is important as a water-soluble polymer. Further, since it is necessary to make the sea-island type fiber into an ultrafine fiber bundle, it is necessary to make the solubility or decomposition property of the island component polymer to be used for the solvent or the decomposing agent different, and in terms of spinning stability, the island component polymer is A polymer having a small affinity and having a smaller melt viscosity than the component polymer under spinning conditions or a polymer having a surface strength smaller than that of the island component polymer is preferred. In a preferred embodiment, a modified polyester such as a compound containing polyvinyl alcohol, polyethylene glycol or an alkali metal sulfonate, or a water-soluble polymer such as polyethylene oxide is preferred. The sea component polymer is a polyvinyl alcohol-based resin (hereinafter collectively referred to as PVA) such as a polyvinyl alcohol homopolymer or a polyvinyl alcohol-based copolymer. Here, the water-soluble polymer refers to a polymer which can be dissolved or removed by decomposition under heat, pressure, or the like by an aqueous solution of water or an aqueous alkali solution or an acidic aqueous solution. When such a water-soluble polymer is used as a sea component, the sea component polymer is expanded in an instant when the nonwoven fabric structure is subjected to a wet heat treatment. The plasticized substrate can be obtained with a dense leather surface, and the substrate for artificial leather formed by the densely assembled nonwoven fabric structure of the ultrafine fiber bundle of the present invention can be obtained with almost no resistance to the shrinkage of the island component polymer. The characteristics of the inductive surface such as texture and fullness, or the practical properties such as abrasion resistance, light resistance, or form stability. Better for good artificial leather products.

The PVA can be obtained by saponifying a resin having a vinyl ester unit as a main constituent unit. A vinyl compound monomer for forming a vinyl ester unit, such as vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl hexanoate, vinyl laurate, vinyl stearate, benzoic acid Among them, vinyl acetate, trimethyl vinyl acetate, and ethylene carbonate, among them, it is easy to obtain PVA, and vinyl acetate is preferable.

The PVA may be a uniform PVA or a modified PVA into which a copolymerization unit is introduced, and it is preferable to use a modified PVA in terms of melt spinning property, water solubility, and fiber properties. By appropriately selecting the kind of the copolymerized monomer used in the modification, the sea-island type fiber can be stably produced without lowering the water solubility of the PVA. The type of the copolymerized monomer, in terms of copolymerization property, melt spinning property, and water solubility of the fiber, an α-olefin having a carbon number of 4 or less such as ethylene, propylene, 1-butene or isoamylene; Further, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, and n-butyl vinyl ether are preferred. The content of the copolymerization unit in the PVA is preferably from 1 to 20 mol%, more preferably from 4 to 15 mol%, and most preferably from 6 to 13 mol%. Further, when the copolymerization unit is ethylene, since the physical properties of the fiber become high, it is more preferable to modify the PVA with ethylene. The ethylene unit content in the ethylene-modified PVA is preferably 4 to 15 mol%, more preferably 6 to 13 mol%.

The PVA is produced by a conventional method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method. Among these, a bulk polymerization method or a solution polymerization method in which polymerization is carried out in a solvent other than a solvent or an alcohol is usually employed. An alcohol used as a solvent for solution polymerization, such as methanol, ethanol, A lower alcohol such as propanol. For copolymerization, use a, a'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), benzammonium peroxide, n-propyl peroxidation A conventional initiator such as an azo initiator such as a carbonate or a peroxide initiator. The polymerization temperature is not particularly limited and is preferably in the range of 0 to 150 °C.

The viscosity average degree of polymerization of the above PVA (hereinafter referred to as the degree of polymerization) is preferably 200 to 500, more preferably 250 to 470, and most preferably 300 to 450. When the degree of polymerization is 200 or more, the melt viscosity is stably combined and has a sufficiently high value. When the degree of polymerization is 500 or less, the melt viscosity is easily discharged from the spinning nozzle, and has a sufficiently low value. Further, by using a polymerization degree of 500 or less, that is, a low polymerization degree PVA, there is an advantage that the dissolution rate when removed by water or an aqueous solution is increased. The degree of polymerization of PVA is determined by the following formula based on JIS-K6726.

P=([η]×10 ³ /8.29) ^(1/0.62)

(P is the viscosity average degree of polymerization, [η] is the intrinsic viscosity measured in water at 30 ° C after re-saponification of PVA and purification)

The saponification degree of the above PVA is preferably from 90 to 99.99 mol%, more preferably from 93 to 99.77 mol%, more preferably from 95 to 99.55 mol%, and most preferably from 97 to 99.33 mol%. When the degree of saponification is 90 mol% or more, the thermal stability is good, and it is difficult to carry out thermal decomposition or saponification treatment at the time of melt spinning, and when the degree of saponification is 99.99 mol% or less, PVA can be stably produced.

The Tm of the above PVA is preferably 160 ° C or more in consideration of the spinning property, more preferably 170 to 230 ° C, more preferably 175 to 225 ° C, and most preferably 180 to 220 ° C. When the Tm is 160 ° C or higher, the PVA can be avoided by reducing the crystallinity. Fiber strength is reduced. Further, PVA has good heat stability and good fiber formability. When the Tm is 230 ° C or lower, the melt spinning temperature can be sufficiently lowered to a temperature lower than the decomposition temperature of the PVA, and the ultrafine fiber bundle forming long fibers can be stably produced.

The proportion of the sea component polymer which is contained in the island-type fiber is preferably such that the ratio of the area ratio of the fiber cross-section is set to 5 to 60%, and preferably 10 to 50%. When the proportion of the sea component polymer in the sea-island type fiber is less than 5%, the spinning stability of the sea-island type fiber is lowered, and the industrial productivity is not good. In addition, when the sea-island type fiber is subjected to wet heat shrinkage by reducing the amount of sea components, the effect of alleviating the friction or interference of the island component is insufficient, and the intended shrinkage state and densification are not obtained, and the impregnation is high in the nonwoven fabric structure. When the solution or the aqueous dispersion of the molecular elastomer is hardened, the sea component is removed, and the void formed between the ultrafine fiber bundle and the polymeric elastomer is insufficient. As a result, the object of the present invention such as a feeling of expansion or a feeling of fullness, a dense surface feeling, and the like cannot be obtained. In addition, when the proportion of the sea component polymer is more than 60%, the shape or distribution state of the island component on the sea-island fiber cross-section becomes unstable, and not only the quality stability is poor, but also the island-type fiber is wet-shrinked, and the island component having the shrinking ability is obtained. The relativeness is insufficient, or the contraction state and the compactness of the purpose cannot be obtained. As a result, the effects of the object of the present invention cannot be obtained. In addition, the higher the proportion of the sea component polymer, the less the amount of the ultrafine fibers in the base material for artificial leather after removing the sea component, and the amount of the polymer elastomer which must be contained in the case where the form stability is a desired level is remarkably increased. The tendency is to increase the load on industrial production in terms of energy or cost when recycling the removed sea component polymer, and the load on the global environment. It will also increase. Therefore, it is preferable to set the ratio of the sea component polymer to be lower in the range allowed by the above various factors.

In the present invention, the sea-island type fiber is in the form of long fibers. In general, the long fiber is a fiber which is not cut into a fiber length of about 10 to 50 mm as long fibers, and the fiber length of the long fiber cannot be uniform. However, in order to achieve the effect of the present invention, the fiber length of the long fiber before the ultrafine refining is preferably 100 mm or more, and is technically manufacturable and physically impossible to cut, and may be several m, several hundred m, several km, or The fiber length of these above.

In the spinning process of the island-type fiber, a nozzle for composite spinning is used. An island component polymer flow path having an average of any number of 8 to 70 ranges in one nozzle hole, and a sea component polymer flow path disposed under the channel for enclosing the island component polymer The plurality of nozzle holes are arranged at equal intervals in a straight line or a circular shape, and are arranged in a plurality of rows in a concentric shape when they are in a straight line or in a circular shape. The island-in-sea type composite fiber in a molten state formed by the sea component polymer and the island component polymer is continuously discharged from each nozzle hole. At any stage from below the nozzle hole to the suction device described below, the cooling air is substantially cooled and hardened by the cooling air, and a jet is used. The suction device such as a nozzle acts on the high-speed air stream, and the composite fiber is uniformly stretched and refined under the target fineness. The high-speed airflow acts at any speed in the range of 1000 to 6000 m/min for the average spinning speed of the general spinning machine. Further, depending on the texture of the obtained fiber web, the composite fiber is opened by a collision plate or a gas flow, and is attracted to the opposite side of the net on the collecting surface of the conveyor belt-like movable net or the like. set. Stacked to form a long fiber web.

When the nozzle for composite spinning is arranged concentrically, generally, one nozzle-shaped suction device is used for one nozzle. Therefore, most of the island-in-the-sea fibers are bundled into the center point of the concentric circle at the time of attraction. In general, since a plurality of nozzles are arranged in a straight line to obtain a desired amount of spinning, almost no fibers exist between the sea-island type fiber bundles discharged from adjacent nozzles. Therefore, in order to make the texture of the fiber web uniform, it is important to perform the fiber opening treatment. When the nozzles for composite spinning are arranged in parallel, a slit-like suction device that opposes a straight line of the nozzle is used. Therefore, when the island-in-the-sea type fibers between the columns arranged in parallel are attracted, they are bundled, and when compared with the nozzles arranged in a concentric shape, a more uniform texture web can be obtained. When this point is compared with a concentric arrangement, it is better to arrange it in a side-by-side configuration.

The resulting long fiber web is preferably subjected to partial heating or cooling by compression, embossing or the like in a subsequent step depending on the desired form stability, and is preferably melted. The sea component polymer has a lower melt viscosity than the island component polymer, and is heated or cooled at any temperature within a temperature range of about 60 to 120 ° C without application to a high temperature of the melting temperature, without constituting the long fiber. The cross-sectional shape of the island-type fiber of the fiber web is greatly lost, and the texture of the long-fiber fiber web can be sufficiently maintained in the subsequent steps. In addition, the form stability of the long fiber web can be improved to a level of handleability such as reelability.

The conventional artificial leather is a generally used method for cutting a short fiber into a fiber web by a cutting machine, and not only a patterning machine but also an oil agent and a crimping treatment suitable for passing through a pattern machine must be used. A series of large-scale equipment such as the length of the fiber, the transfer of the original cotton after cutting, and the opening of the fiber have problems in terms of production speed, stable production, and cost. Moreover, the other method of passing short fibers is a papermaking method, but since the method also requires an accessory device such as a cutting machine device, there is still the same problem as the above method, since the basis weight of the non-woven fabric that can be manufactured stays at about 200 g. The value of /m ² is very limited in its use for artificial leather products. In the method of using the short fibers, the production method of the present invention is carried out in a single step without forming a fiber web from the spinning, and the apparatus is very compact and simple, and is excellent in production speed or cost. Further, since there is no problem that recombination occurs by combining various conventional steps and equipment, stability and productivity are also excellent. In addition, when compared with a nonwoven fabric structure which is formed by a conventional fiber or a polymer elastic body, the nonwoven fabric structure obtained from the long fiber and the artificial leather base using the same The material or the artificial leather exhibits excellent characteristics in terms of physical stability such as form stability, mechanical strength, surface friction durability, and adhesion strength of the grain surface.

According to the production method of the present invention, fibers having a very small fiber diameter which cannot be used by a conventional patterning machine can be used, and since the crimping treatment is not required, the fiber itself cannot be made bulky, and self-mechanical accumulation is possible. At the stage, it is possible to stably obtain a state in which the non-woven fabric structure is more extremely dense, and by combining the following methods, it is possible to obtain an extremely high-quality artificial leather which is impossible to realize by conventional artificial leather.

Regarding the fiber diameter, when manufacturing a nonwoven fabric structure using conventional short fibers, it is necessary to have a fiber diameter of a certain amount or more suitable for a fiber opening device or a pattern machine. Specifically, the cross-sectional area must be 200 μm ² or more, and in consideration of industrial safety productivity, fibers having a thickness of about 300 to 600 μm ^{2 are} generally used. In the production method of the present invention, since the fiber thickness used is not limited by the apparatus, ultrafine fibers having a cross-sectional area of 100 μm ² or less may be used, but the cross-sectional area must be obtained when the density of the non-woven fabric structure for the purpose of the present invention is obtained. of 70 ~ 350μm ^2, to form a step following after the stability, handling capability, preferably to 80 ~ 300μm ^2. By using the long fiber of the cross-sectional area, the obtained long fiber web can be obtained in any cross section parallel to the thickness direction, and the cross section of the fiber which is almost perpendicular to the cross section is 100 to 600 pieces/mm ² (preferably 150~). The fiber distribution state in the average density of 500/mm ² ) range, and the dense non-woven fabric structure of the present invention can be finally obtained by the complexation or shrinkage of the subsequent steps.

In the present invention, the compactness of the nonwoven fabric structure constituting the base material for artificial leather obtained is important, in other words, it is necessary to improve the compactness of the nonwoven fabric structure constituting the surface layer portion of the base material for artificial leather. Therefore, the cross-sectional area of the extremely elongated fiber bundle obtained by removing the sea component polymer from the sea-island type fiber must be at least 700 μm ² or less. When the cross-sectional area of 700 μm ² or less, for example, the polymer constituting the extremely elongated fiber is ethylene terephthalate, the fine fiber bundle has a fineness of approximately 10 dtex or less. In order to form a substrate for artificial leather which can produce extremely high-quality fluff-toned artificial leather or densely creased grain-like artificial leather, it is necessary to have a dense structure of the nonwoven fabric obtained by the fiber bundle of the thickness. . In other words, in order to shorten the artificial fluff of the n-wool leather-like ultrafine fiber fluff and have a dense surface texture, the cross-sectional area of the ultra-long fiber bundle is preferably 500 μm ² or less, more preferably 400 μm ² or less. The lower limit of the cross-sectional area of the extremely thin fiber bundle does not affect the characteristics of the base material for artificial leather, and the strength of the artificial leather is significantly reduced, the surface friction durability, etc. The manufacturing step of the artificial leather is limited. In the present invention, the cross-sectional area of the extremely elongated fiber bundle must be at least 170 μm ² or more, preferably 180 μm ² or more, and more preferably 190 μm ² or more.

In the present invention, the number of extremely elongated fibers constituting a bundle of ultrafine fiber bundles is such that the flexibility of the extremely elongated fiber bundle, that is, the ease of complexation in the nonwoven fabric structure or the resulting flexible substrate for artificial leather. The number of the properties is eight or more, and the flexibility of the extremely long fiber bundle, the deformability of the cross-sectional shape, and the color developability of the base material for artificial leather finally obtained are 70 or less. In addition, the number of extremely elongated fibers is preferably from 10 to 60, more preferably from 12 to 45. When the number of the extremely thin fibers is seven or less, the flexibility of the extremely long fiber bundle is not good, and the ratio of the number of restraint strips, that is, the composition of the extremely elongated fiber bundle, when the polymer elastic body is contained in the nonwoven fabric structure is not preferable. When the proportion of the number of the strips disposed on the outermost circumference of the number of the strips is large, depending on the polymer elastomer, the flexibility of the extremely long fiber bundle is easily impaired, and the texture of a small amount of the polymer elastomer is easily cured. Therefore, it is easy to display the texture of the base material for artificial leather due to the spot of the state of the polymer elastomer, and it is difficult to confirm the value as an industrial product. In addition, when the number of extremely thin fibers is more than 70, one strip of the extremely long fibers itself is excellent in flexibility, but the contact area between the extremely elongated fibers in the extremely elongated fiber bundle is increased and is in conflict with each other. There is a tendency for the flexibility to deteriorate. Further, in the cross-sectional shape of the extremely elongated fiber bundle, it is deformed by a compressive force perpendicular to the fiber axis, that is, it is easy to cause flattening, and constitutes a fiber bundle. When the fibers are widened, the fiber bundles are liable to become loose, the bulkiness of the fiber bundles is increased, and the critical value of the densification of the nonwoven fabric structure is lowered. The bulkiness is also the same at the stage of the sea-island type fiber, and the fiber is easily flattened in cross-sectional shape, and the filling effect of the fiber cross-section of the non-woven fabric structure is lowered, and the densification is prevented before the sea component is removed.

For this reason, it is understood that at least 70 or less of the fiber bundles are not easily flattened, and the flatness of the extremely long fiber bundle of the base material for artificial leather finally obtained must be 4.0 or less, preferably 3.0 or less. Moreover, the surface of the substrate for artificial leather is remarkable by the flattening of the extremely elongated fiber bundle, and the width of the fiber bundle, that is, the projection size of the extremely elongated fiber bundle when viewed from the surface is preferably 10 to 60 μm, preferably 15 ~45μm is better. When the projection size of the extremely long fiber bundle is larger than 60 μm, the densification of the fiber bundle is insufficient, and in particular, as the pile-like artificial leather, the bundle of the woven fibers which can form the pile is reduced, and only the surface of the pile having a low appearance quality can be obtained. In addition, when the projection size of the extremely thin fiber bundle is less than 10 μm, the fiber bundle is extremely easy to be densified, but the fiber bundle is not completely flattened, and the diameter of the fiber bundle itself is less than 10 μm, which is very fine, especially even if fluff is formed. In the case of the fluff of the artificial leather, since the fiber bundle is easily cut by the raising process, the pile is reduced, and it is difficult to obtain a good appearance quality, and the surface has poor abrasion resistance.

When the non-woven fabric structure of the base material for artificial leather is formed by forming the extremely elongated fiber bundle having the above characteristics, the number of cross-sections of the extremely elongated fiber bundle which is almost perpendicular to the cross section can be obtained in any cross section parallel to the thickness direction thereof. 1500~3000/mm ² , an extremely dense fiber assembly structure that is not known. When the amount is less than 1500/mm ² , only the density of the ultrafine fiber bundle is reduced, and a space in which the ultrafine fiber bundle is not present is generated, and when the number density of the ultrafine fiber bundle is reduced, there is no uniform dispersion. There is almost no tendency to have a loose range of dense range. When the space generated between the ultrafine fiber bundles becomes large, a continuous film of a thick polymer elastomer is formed, and the texture of the artificial leather becomes hard, with a great coarseness. The plaque causes the appearance of a surface appearance or deterioration of surface properties. When it is more than 3,000/mm ² , the observer is a dense fiber assembly formed by the base material for artificial leather of the present invention, and only the nonwoven fabric structure is forcibly compressed in the thickness direction by hot pressing treatment or the like. By the contraction force of the woven fabric or the like which is bonded to the nonwoven fabric structure, the structure which is forcibly compressed in the longitudinal direction or the width direction is collapsed and flattened in the direction in which the ultrafine fiber bundle is compressed, and the physical properties are lowered or On the contrary, the texture will become harder, preferably 2000~2700/mm ² .

When the nonwoven fabric structure is densified by a complexing treatment or the like, the base material of the artificial nonwoven fabric is densified by a complexing treatment or the like, and the cross-sectional area of the fiber becomes 300 to 600 μm when it is a very fine fiber bundle. ^Since the thickness is about ² , the density of the nonwoven fabric structure is insufficient, and the density of the cross section of the ultrafine fiber bundle is as high as 200 to 600 pieces/mm. ² , there are also about 750 / mm ² . Assuming that a non-woven fabric having a number density of the ultrafine fiber bundles of more than 750/mm ² is produced in the prior art, the fiber bundle itself is damaged by excessive needling treatment, and compression is forced by the above-described hot pressing or the like. The treatment may cause the cross-sectional shape of the fiber bundle to be greatly deformed, or the densification by the treatment alone may result in a large spot in the void between the fiber bundles, and the obtained substrate for artificial leather and the object of the present invention The difference is completely different. Further, in the conventional nonwoven fabric structure in which the number density of the fiber bundles is about 200 to 600 pieces/mm ² , when the polymer elastic body is contained in the fiber bundle, the number density of the ultrafine fiber bundles is reduced, A continuous film of a thick polymer elastic body is formed between the ultrafine fiber bundles, and the texture of the composite structure of the non-woven fabric structure and the polymer elastic body becomes a hard feeling more than necessary, and the fibers or the polymer elastomer are densely dispersed everywhere. In the range in which the collection exists and in the range in which the fibers and the polymeric elastomer are almost completely absent, it is impossible to obtain a person having a large coarse patch. In this case, the nonwoven fabric structure of the present invention has an ultra-dense structure in which extremely fine fiber bundles are extremely densely and uniformly aggregated, and when a polymer elastomer is contained in the nonwoven fabric structure, a polymer formed between the ultrafine fiber bundles can be formed. The thickness of the continuous film of the elastomer is reduced, and the element formed by the polymer elastic body is also smaller, and can be uniformly distributed. Therefore, it is possible to suppress the occurrence of significant coarse spots on the inside of the substrate for artificial leather.

In the present invention, when the nonwoven fabric structure is formed by the extremely long fiber bundle satisfying the above requirements, the fiber diameter of the extremely elongated fiber itself is not particularly limited, and at least the pile portion is formed in order to form a pile surface having a beautiful appearance or touch with the object of the present invention. The medium-length slender fiber is preferably 0.8 to 15 μm, more preferably 1.0 to 13 μm, particularly preferably 1.2 to 10 μm, and most preferably 1.5 to 8.5 μm. When the fiber diameter of the extremely elongated fiber is more than 15 μm, the appearance quality when the pile-like artificial leather is adversely affected, for example, the surface of the pile has a spot, and the smoothness of the touch is impaired, so that it is not desired. In addition, when the fiber diameter of the ultra-long fiber is less than 1.0 μm, the fluff-like artificial leather is dense, but the overall appearance quality or surface characteristics are adversely affected. For example, the surface of the pile is whitened and resistant. The surface abrasion resistance such as peeling property also deteriorates.

When the weight per unit area or thickness of the obtained long fiber web is insufficient, the rubbing treatment is performed at a desired unit weight area and thickness (a long fiber web is supplied in a direction perpendicular to the flow direction of the step, and almost All are folded in the width direction, or the web supplied in a direction parallel to the flow direction of the step is folded toward its length) or the volume is made to overlap a plurality of long fiber webs. When the form stability of the non-woven fabric structure formed by the sea-island type fiber or the denseness of the fiber is insufficient, when the sea-island type fiber of the non-woven fabric structure is aligned in the thickness direction, the conventional method such as a needle punching method is used. Mechanical complexation treatment. Thereby, a three-dimensional complexing treatment can be performed between the fibers constituting the long fiber web, in particular, the layers adjacent to the layered long fiber web which is rubbed or laminated. When the complexing treatment is performed by the needle punching method, the type of the knitting needle (the shape or number of the knitting needle, the shape or depth of the thread, the number or position of the thread), and the number of needles of the knitting needle (needle knitting needle) are appropriately selected. The density of the needles of the needles in the voids and the needling density per unit area of the number of strokes acting on the unit area of the long fiber web, and the needling depth of the needles (for the long fiber web) Various processing conditions such as the depth of the action of the knitting needle are implemented.

The type of the knitting needle can be appropriately used in the same manner as in the case of producing artificial leather using conventional short fibers, but the number of the knitting needle, the depth of the thread, and the number of the thread are particularly important in terms of the effect of the present invention. It is preferable to use a knitting needle of the following type.

The number of the knitting needle is a factor that affects the density or surface quality obtained after the treatment, and at least the blade portion (the filament formed at the front end of the knitting needle) The size of the part must be less than 30 (thin) (the height of the cross-sectional shape is a regular triangle, or the diameter of the circle is about 0.73 ~ 0.75mm), preferably 32 (about 0.68 ~ 0.70mm) ) The range of ~46 (about 0.33~0.35mm), and the better is the range of 36 (about 0.58~0.60mm)~43 (about 0.38~0.40mm). The size of the blade portion is larger than that of the No. 30 (thick) needle, the degree of freedom of the shape or depth of the thread is high, and the strength or durability of the needle is better, but on the contrary, a large aperture remains on the surface of the nonwoven structure. The needle piercing mark does not produce a dense fiber assembly state or surface quality for the purpose of the present invention. Further, since the friction between the fibers in the long fiber web and the knitting needle becomes too large, it is necessary to provide an excessive amount of the oil for needling treatment, which is not desirable. Further, the knitting needle having a blade portion smaller than the size of 46, is not industrially produced in terms of strength or durability, and it is impossible to set a twist of a proper depth in the present invention. The cross-sectional shape of the blade portion is preferably an equilateral triangle in the present invention in terms of easy stretchability of the fiber or a small frictional force.

The depth of the crepe of the present invention is the height from the deepest portion of the crepe to the front end of the crepe. The general shape of the silk is the height corresponding to the height of the front end of the yarn protruding from the side of the needle (also known as the upward bending), and the depth of the deepest part of the thread formed from the side of the needle to the inside (also The height called the slit depth). The depth of the filature is at least the diameter of the island-in-the-sea fiber, preferably 120 μm or less. When the depth of the silk is lower than the diameter of the island-type fiber, the island-type fiber is extremely difficult to be hooked into a silk, so it is not desirable. Further, when the depth of the twisted yarn is more than 120 μm, the fiber is liable to be hooked. On the contrary, a large-aperture needle sticking tends to remain on the surface of the nonwoven fabric structure, and it is difficult to obtain a dense fiber assembly state or surface quality for the purpose of the present invention. and Further, the depth of the ruthenium yarn is preferably any multiple of the range of 1.7 to 10.2 times the diameter of the sea-island type fiber, and more preferably from the range of 2.0 to 7.0 times. When the depth of the silk is less than 1.7 times, the sea-island type fiber is not easily hooked into a silk, and even if the number of needles is increased, the complexing effect cannot be obtained. Further, when it is more than 10.2 times, the hook of the island-type fiber is improved. The ease of silk, of course, there is a tendency for the damage of the island-type fiber to be cut or broken, and it is not desirable.

The number of twisted yarns of the present invention is appropriately selected under the effect of the desired complexing effect within the range of 1 to 9 needle hooks, and in order to obtain the dense non-woven fabric structure necessary for the present invention, the needle-punching complex treatment is mainly The knitting needle to be used, that is, the knitting needle used for the needle punching treatment of at least 50% of the number of needle punches described below, must have six needle hooks. Further, in the present invention, the number of threads of the knitting needle used in the needle-punching treatment is not necessarily one, and for example, one needle hook and six needle hooks, three needle hooks, and six needles may be appropriately combined. Needle hooks, 6 needle hooks and 9 needle hooks, 1 needle hook, 6 needle hooks and 9 needle hooks, etc., can be used in any order. In a needle having a plurality of needle hooks, the position of each thread is completely different from the distance from the front end of the needle, and there are several twists of the same distance. In the latter knitting needle, for example, the cross-sectional shape of the blade portion is an equilateral triangle, and each of the three apexes is attached to a front end of each of the hooks, and a knitting needle is attached at the same distance. In the present invention, the knitting needle mainly used in the complexing treatment is the knitting needle of the former. This is a knitting needle with a plurality of needle hooks at the same distance. Since the blade portion having the knitting needle is thick and the thickness of the thread is large, the complexing effect is high, but the blade portion is excessive. Significant shortcomings of thick and silky. In addition, the use of the latter weaving When the needle is excessively subjected to the needling treatment, since a plurality of fibers of ten to several tens of strands are formed at one place, the position in the thickness direction of the nonwoven fabric structure is excessively distributed, so that it is difficult to obtain the object of the present invention. The tendency of dense structures. In other words, in any cross section parallel to the thickness of the nonwoven fabric structure, there are many fibers which are almost parallel to the cross section, and the number density of fibers perpendicular to the cross section tends to be extremely reduced. However, since a strong complexing effect can be obtained even with a small number of twisted yarns, it is preferable to use the latter knitting needle in the partial complexing treatment. For example, in any stage from the initial stage to the middle stage of the complexation treatment, the knitting needle of the latter is subjected to complexation treatment without damaging the dense structure of the target, and then the method of forming the dense structure of the target using the knitting needle of the former is One of the preferred forms. Further, in the present invention, when the number of twisted yarns is six needle hooks, the total number of twisted yarns that pass through the nonwoven fabric structure at the tip end of the needle to the twisted yarn that does not penetrate and substantially acts on the nonwoven fabric structure is obtained. It does not contain silk which does not act on the portion of the nonwoven structure. For example, when the number of twisted yarns formed in the knitting needle is 9 needle hooks, when the needle piercing is deepest at the deepest point, when the three needle hook yarns are left in the non-woven fabric structure, the processing conditions are substantially The number of twists is equal to the effect of acupuncture treatment of 6 needle hooks.

The total number of needles of the needles is preferably any value in the range of 800 to 4000 needles/cm ² , more preferably in the range of 1000 to 3500 needles/cm ² . When the knitting needle having a plurality of twists at the same distance is used, the number of needles to be subjected to the needling treatment is about 300 needles/cm ² or less, preferably about 10 to 250 needles/cm ² . When a needle having a plurality of twisted yarns at the same distance as described above is used and a needle punching treatment of more than 300 needles/cm ² is performed, since the fibers are mostly aligned in the thickness direction, even a needle punching treatment using another knitting needle is used. Further, it is difficult to increase the number density of the nonwoven fabric structure, such as heat shrinkage treatment or press treatment. When the total number of needles of the knitting needle is less than 800 needles/cm ² , not only the densification is insufficient, but in particular, the integration of the nonwoven fabric structure by the fiber complexing treatment between the different layers of the long fiber web is insufficient. When the amount of the needle is more than 4,000 needles/cm ² or less, depending on the shape of the needle, the needle of the fiber may be damaged by cutting or cracking, and the damage of the fiber is particularly serious. The form stability of the nonwoven fabric structure is greatly reduced and the compactness is also lowered.

The obtained nonwoven fabric structure and the substrate for artificial leather have mechanical properties such as dimensional stability and tensile strength, and alignment properties of fibers in the thickness direction, and the thickness of the long fiber web is higher than that of the needle. More effective is better. Therefore, the depth of needling of the needle is preferably set to be at least the depth of the filament at the foremost end side of the needle passing through the entire thickness of the long fiber web. In particular, in the knitting needle in which the twisted yarn which is necessary for the present invention is six needle hooks, in order to maximize the complexing effect of the object of the present invention, it is important that all of the twisted yarns have no through-seam. In other words, the filament that is furthest from the front end acts on the needle by the depth of the needle stuck in the long fiber web. When all the filaments were passed, the dense fibers of the purpose of the present invention could not be obtained because the filaments of the six hooks protruded from the entire long fiber web through the long fibers of the hook yarn. The number of the filaments that have not passed through the long fiber web is preferably 2 needle hooks to 5 needle hooks of the 6 needle hooks, and more preferably 3 needle hooks or 4 needle hooks. Further, in order to realize a dense structure which is not conventionally known, the needle punching treatment of 50% or more of the number of needle punches must be set in the front end of the needle. In order to penetrate the depth of the long fiber web, it is preferred to set the twisting of 70% or more of the needle at the front end of the needle to the depth of the needled web of the long fiber web. However, when the depth of the acupuncture treatment is too deep, when the silk thread is 6 needle-crochet needles, not only the above-mentioned dense structure cannot be obtained as described above, but also the needle thread is 1 needle hook, 2 needle hooks, and 3 needle hooks. 4 needle hooks, 5 needle hooks, or 7 needle hooks, 8 needle hooks, 9 needle hooks, or 10 needle hooks or more, that is, depending on the number of silks, The damage of the fiber is remarkable due to the twisted yarn, and the fiber tends to be cut when it is extremely extreme, or the needle stick tends to remain on the surface of the nonwoven fabric structure. Therefore, when setting the needling condition, it is necessary to pay special attention to such a situation. .

In order to suppress the damage or cutting of the fiber by the needling treatment, and to suppress the charging or heat generated by the strong friction between the knitting needle and the fiber, the manufacturing process of the long fiber web is followed by It is preferred to impart an oil agent in any stage prior to the combination of the treatment steps. The method of imparting may be a conventional coating method such as a spray coating method, a reversible roll coating method, a contact roll coating method, a slit coating method, or the like, wherein the spray coating method is non-contact to the long fiber web and can be used in A low viscosity oil agent which is impregnated in a short time in the inner layer of the long fiber web is preferred. Moreover, after the manufacturing step of the long fiber web referred to herein, the sea-island type fiber is subjected to melt spinning treatment, and is captured on a collecting surface of a mobile net or the like. After the stage of accumulation. In the present invention, the oil agent to be applied before the complexation treatment may be an oil agent formed of one component, or may be added by using a plurality of oil agents having different effects, or may be sequentially imparted thereto. . The oil agent used in the present invention is a friction effect between the knitting needle and the fiber, and the smoothing effect of the friction between the metal and the polymer is high. The oil agent is preferably a mineral oil-based oil agent or a polyoxyalkylene-based oil agent, and in the latter case, an oil agent mainly composed of dimethyloxane is more preferable. When using a polyoxyalkylene-based or high-smoothing oil agent, when the smoothing effect is too strong, the effect of the hooking of the silk yarn will cause a significant decrease in the complexing effect, in particular, the suppression of the coefficient of friction between the fibers is remarkable. In the case where it is lowered and the complex state cannot be maintained, it is more preferable to use an oil agent having a high combined friction effect, for example, a mineral oil type oil agent. However, since the seawater component of the sea-island type fiber of the present invention uses a water-soluble polymer, water or an aqueous solution is used when the fiber is changed into a very fine fiber bundle, and in particular, the polyoxyalkylene-based oil agent is not removed at the same time as the ultrafine fiber bundle is removed until At the stage of the base material for artificial leather, it is likely to remain on the surface of the ultrafine fiber or the surface of the polymeric elastomer. Therefore, when the obtained base material for artificial leather is used for the fluff-like artificial leather, the oil agent forming treatment spot (for example, the stained state is spotted) remaining in the water bath treatment which is typically performed by the dyeing treatment, or After the processing in the bath or the like is not completely removed, the residual oil agent weakens the fixed state of the pile fibers on the nonwoven fabric structure, and is easily peeled off, etc., in particular, it is necessary to pay attention to the use of polyoxyalkylene-based oil. Agent. When a mineral oil-based oil agent is used in combination with a polyoxyalkylene-based oil agent, it is preferable to use a surfactant (for example, a polyoxyalkylene-based surfactant or the like as an antistatic agent) when the static electricity is remarkable by friction.

In the non-woven fabric structure in the formation stage of the sea-island type fiber, the final necessary average number density (the number of the unit cross-section of the fiber cross-section which is almost perpendicular to the cross-section in the cross section parallel to the thickness direction) is 1000 to 3500 pieces/mm ^{2 .} Preferably, it is 1100~3000 pieces/mm ² , and more preferably any value in the range of 1200~2500 pieces/mm ² . In order to obtain a dense structure having the average density range, after the complexing treatment such as needling treatment, heat shrinkage treatment by hot air, warm water, steam or the like is used. By combining one or more of these treatments, a dense structure for the purpose of the present invention can be finally obtained. Of course, in addition to the complexation treatment or the shrinkage treatment, it is preferred to carry out the pressing treatment. When the pressing treatment and the complexing treatment are used, the treatment may be performed before or after the complexation treatment, or the pressing treatment and the complexation treatment may be simultaneously performed. Further, when used in combination with the shrinking treatment, it can be carried out before or after the shrinking treatment, but the pressing treatment and the shrinking treatment are carried out simultaneously, and the shrinkage state becomes uneven, so that it is not desired.

The heat shrinkage treatment is carried out after the needling treatment, and at least the wet heat treatment must be carried out in the present invention. The wet heat treatment is a heat shrinkage treatment in which the non-woven fabric structure after the needle-punching treatment is applied or in a high-temperature, high-humidity gas atmosphere under the desired compactness. For example, when the density of the nonwoven fabric having an average density of about 800 to 1100/mm ² is obtained, first, densification is performed by acupuncture treatment until 350 to 750/mm ² , and then the target compactness is performed. Heat shrinkage treatment. In order to carry out the heat shrinkage treatment, the long fiber web must be formed of a sea-island type fiber containing a heat-shrinkable component, and a long fiber web made of a shrinkable fiber in addition to the sea-island type fiber is used, and the laminate is additionally manufactured. A shrinkable fiber web is preferred. In order to obtain a heat-shrinkable island-in-sea type fiber, a heat-shrinkable polymer may be used as the sea component polymer, the island component polymer, or both, but in the present invention, at least the above heat is used. The shrinkable polymer acts as an island component polymer. The conditions of the wet heat shrinkage treatment are as long as at least the island component polymer has sufficient shrinkage action and the sea component polymer is expanded. It is not particularly limited, and it can be appropriately set depending on the heat shrinkage treatment method to be used or the treatment amount of the object to be treated, for example, by continuously supplying saturated water vapor, and controlling it in a controlled manner. A method of introducing a temperature of 65 to 100 ° C and a relative humidity of 70 to 100% in any environment of temperature and humidity, or for expanding the sea component polymer in the nonwoven structure. The plasticizer can be supplied with a sufficient amount of water, or supplied by the subsequent method to shrink the island component polymer and the sea component polymer. A preferred method is a method in which heat required for plasticization is continuously applied to the nonwoven fabric structure. The method of imparting heat to the non-woven fabric structure having moisture is introduced into a method of controlling the environment in which temperature is sought, a method of causing the air of the temperature to act directly on the nonwoven fabric structure, or an electromagnetic wave such as infrared rays is applied thereto. A method in which the nonwoven fabric structure acts and the nonwoven fabric structure is heated to a desired temperature is a preferred example. When the area of the non-woven fabric is widened, it is easy to generate spots in a heat-shrinkable state depending on the influence of its own weight, and the purpose of controlling the length of the shrinkage is to control the length of the sheet-like nonwoven structure, Depending on the position in the width direction, it is preferable to control different temperature conditions.

In order to densify the nonwoven fabric structure formed of the sea-island type fiber, the following impregnation treatment of the polymer elastomer is carried out in advance, in addition to the complexing treatment or the heat shrinkage treatment by the above-mentioned needling treatment, It is preferred to use a pressing treatment. For example, when the average density of the non-woven fabric is about 1000 to 1200/mm ² , the heat shrinkage treatment can be performed until the densification is 600 to 900/mm ² , and the pressing is performed as a target. Compactness. Specific examples of the pressing treatment are as follows: a method of directly pressing in a wet state after the above-mentioned wet heat shrinkage treatment, a method of pressing in a wet heat shrinkage treatment, a dry state, and a state in which a part of moisture remains without drying at all. The method of suppression, etc. For example, the temperature of the press treatment is a method of hardening the softening component at a temperature lower than the surface temperature of the nonwoven fabric structure and pressing the surface before the heat cooling of the wet heat shrinkage treatment or the drying treatment, and the surface of the nonwoven fabric structure. A method of softening a component at a higher temperature, and then evaporating and compressing the water. By adopting this treatment method, since the densification by the press treatment is performed almost simultaneously with the heat shrinkage treatment, the uniform densification state can be obtained only by performing the press treatment, and excellent production efficiency can be obtained. In the sea-island type fiber constituting the non-woven fabric structure, the softening temperature of the sea component polymer is lower than the softening temperature of the island component polymer by 20 ° C or more, preferably 30 ° C or less, and is subjected to a heat shrinkage treatment. It is more effective by densification. At this time, by heating from the softening temperature of the near-sea component polymer to a temperature range lower than the softening temperature of the island component polymer and the contraction temperature of the island component polymer is higher, only the sea component polymerization in the sea-island type fiber The shrinkable island component polymer is shrunk in a state where the object is softened or nearly softened, and the degree of freedom of the island component is increased. When the shrinkage is sufficiently performed, when the nonwoven fabric structure is subjected to a pressing treatment in a state where the softening temperature of the sea component polymer is not lowered, the nonwoven fabric structure is compressed to a more dense state, and the article is cooled to room temperature. A nonwoven fabric structure fixed in a desired dense state can be obtained. In addition to the advantages of densification of the press treatment, for example, the surface of the nonwoven fabric structure can be fixed in a more smooth state. By the smoothing treatment, the extremely dense collection state of the ultrafine fiber bundle of the largest feature among the substrates for artificial leather of the present invention can be more effectively produced. In other words, since the surface of the base material for artificial leather can be made smoother, the amount of polishing of the pile forming treatment by the rubbing treatment or the like can be reduced when the pile-like artificial leather is produced, and when the granular artificial leather is produced, there is no The surface of the substrate is subjected to heat pressing, rubbing treatment or the like to form a very fine grain layer having a smooth thickness of 50 μm or less.

In the dense non-woven fabric structure having a number density of 1,000 to 3,500 / mm ² and preferably 1300 to 3,000 / mm ² , the high content of the sea component polymer is required before or after removal. Molecular elastomer. The method to be contained, for example, a solution or dispersion containing a polymer elastomer, and a method of solidifying by a conventional hydrazine method or a wet method. The impregnation method may be a treatment in which a non-woven fabric structure is immersed in a bath filled with a polymer elastomer liquid, and then twisted in a liquid-containing state by a pressing roll or the like, that is, a dipping method or a bar coating method. Any of various conventional coating methods such as a method, a knife coating method, a roll coating method, a vertical coating method, and a spray coating method. There may be one method or a combination of several methods.

The polymer elastomer contained in the nonwoven fabric structure may be any conventional user of the substrate for artificial leather, and may be used, for example, a polyurethane elastomer, an acrylonitrile elastomer, or an olefin. The elastomer, the polyester elastomer, the acrylic elastomer, preferably at least one selected from the group consisting of polyurethane elastomers and acrylic elastomers. The polyurethane elastic system may be at least one polymer polyol selected from the group consisting of polyester diols, polyether diols, polyether ester diols, and polycarbonate diols having an average molecular weight of 500 to 3,000. And at least one selected from the group consisting of 4,4'-diphenylmethane diisocyanate and isophorone A polyisocyanate such as an aromatic group, an alicyclic system or an aliphatic diisocyanate such as a cyanate ester or a hexamethylene diisocyanate is used as a main component, and at least one ethylene glycol and B are combined at a predetermined molar ratio. a low molecular compound having two or more active hydrogen atoms such as a diamine, and various polyamine groups obtained by polymerization in a one-stage or multi-stage manner by a melt polymerization method, a bulk polymerization method, a solution polymerization method, or the like. The content of the polymer polyol component which is contained in the formate elastomer or the polyurethane elastomer is preferably from 15 to 90% by mass. Further, the acrylic elastomer has a glass transition temperature of the homopolymer of -90 to -5 ° C, preferably a non-crosslinkable monomer, for example, at least one selected from the group consisting of methyl acrylate and n-butyl acrylate. a soft component such as isobutyl acrylate, isopropyl acrylate, n-hexyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, and the glass transition temperature of its homopolymer is 50 to 250 ° C a range, preferably a non-crosslinkable monomer, for example at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, methacrylic acid cyclohexane A hard component such as an ester or (meth)acrylic acid is reacted with a monofunctional or polyfunctional ethylenically unsaturated monomer unit obtained by forming a crosslinked structure or an ethylenically unsaturated monomer unit introduced into a polymer chain to form a cross. The compound obtained by the combination structure, for example, at least one selected from the group consisting of ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4- Crosslinking formation of butanediol di(meth)acrylate Various acrylic elastomers obtained by polymerization of an ethylenically unsaturated monomer formed from a component. A base material for artificial leather obtained by using a polyurethane elastomer as a main body elastomer, which is excellent in balance of texture or mechanical properties, and contains durability It is also better in terms of balance. Further, when the acrylic elastomer is used as a base material for an artificial leather, when the acrylic elastomer is compared with the polyurethane elastomer, the adhesion to the extremely long fiber bundle is low, and the pile fixing effect at the time of formation of the pile is lacking. It is not easy to form a fluffy artificial leather, and since the degree of hardening of the texture can be suppressed in terms of content, it is more preferable to form a grain-like artificial leather. The polymer elastomer may be mixed with different types, or may be different in number, and may contain a polymer such as a synthetic rubber or a polyester elastomer as needed in addition to the polymer elastic body containing the main body. A polymeric elastomer composition of an elastomer.

The polymer elastomer liquid such as a solution or a dispersion of a polymer elastomer is impregnated into the nonwoven fabric structure, and then the polymer elastomer is solidified by a conventional hydrazine method or a wet method to obtain polymer elasticity. The body is fixed in the body of the non-woven fabric. The formula method referred to herein means a method in which all of the solvent or the dispersant is removed by a drying treatment or the like to fix the polymer elastomer in the nonwoven fabric structure. In addition, the wet method referred to herein means a non-woven fabric structure in which all of the polymer elastomer is impregnated with a non-solvent or a coagulant of a polymeric elastomer, and a polymer to which a sensible gelling agent or the like is added is used. The elastomer liquid is a method in which the impregnated nonwoven fabric structure is subjected to heat treatment, and the solvent or the dispersant is removed in advance to fix the polymer elastomer in the nonwoven fabric structure or to be completely fixed. Further, in order to completely fix the solidified polymeric elastomer, it is preferred to carry out a curing treatment such as heat treatment after removing the solvent or the dispersing agent.

The concentration of the polymer elastomer solution, that is, the content of the polymer elastomer in the polymer elastomer solution is preferably from 0.1 to 60% by mass. Polymer elastomer In the liquid, a coloring agent such as a dye or a pigment, a coagulating agent, an antioxidant, an ultraviolet absorber, a fluorescent agent, an antifungal agent, or the like is appropriately blended in a range that does not impair the properties of the substrate for artificial leather finally obtained. Soaking agent, antifoaming agent, smoothing agent, water repellent, oil repellent, tackifier, extender, hardening accelerator, foaming agent, water-soluble polymer compound such as polyvinyl alcohol or carboxymethyl cellulose, etc. Various additives blended in the polymer elastomer liquid contained in the base material for artificial leather. The amount of the polymer elastomer or the polymer elastomer composition contained in the nonwoven fabric structure is appropriately adjusted depending on the required mechanical properties, durability, texture, etc., for the purpose of use, but is formed by a very fine fiber bundle. When the unit volume weight of the nonwoven fabric structure is 100, the basis weight of the polymer elastomer is preferably in the range of 1 to 80% by mass, more preferably in the range of 2 to 60% by mass, and 5 to 40. The range of mass % is the best. When the content of the polymer elastomer is less than 1% by mass, the polymer elastomer is not uniformly contained, so that the content of the polymer elastomer in the substrate for artificial leather is intense, and the quality of the substrate for artificial leather is high. It is not easy to stabilize. In addition, when the content of the polymer elastic body is more than 80% by mass, the nonwoven fabric structure is extremely dense, and the texture of the base material for artificial leather is significantly hardened, and the rubber feeling is strong, which is not desirable.

In the present invention, the method of removing the sea component polymer from the sea-island type fiber constituting the nonwoven fabric structure before or after the inclusion of the polymer elastomer is a non-solvent or non-dispersant agent of the island component polymer, and the content is high. When the molecular elastomer is removed, the method of treating the nonwoven fabric structure with a liquid having a non-solvent or non-dispersant liquid of the polymer elastomer and having a solvent or a dispersant of the sea component polymer. For example, when a polymer which is soluble in water such as polyvinyl alcohol or the like is used as the sea component polymer, the polymer may be removed by warm water at a soluble temperature, and the above-mentioned sulfonic acid may be used. When the alkali-decomposable modified polyester which is copolymerized with an alkali metal salt compound or the like is used as a sea component polymer, an aqueous solution of an alkaline decomposing agent such as an aqueous sodium hydroxide solution can be removed at an appropriate temperature. By the sea component polymer removal treatment, the sea-island type fiber is made into a very elongated fiber bundle formed of an island component polymer, and the artificial manufacture of the invention having a basis weight of preferably 300 to 1800 g/m ^{2 is obtained} . Leather substrate.

The base material for artificial leather obtained by converting the sea-island type fiber into a very long-length fiber bundle is different from the conventional base material for artificial leather, and is formed, for example, between extremely thin fiber bundles in addition to the above points. The void size is 70 μm or less, preferably a minimum value of 60 μm or less, and a uniform, small-sized spot. In this process, the sea-island type fiber is spun and laminated to form a three-dimensionally entangled nonwoven fabric structure. (1) The cross-sectional area is about 350 μm ² or less, that is, the fiber diameter is about 21 μm or less, and it is difficult to flatten. The island-type fiber of the island number is spun, and the fiber web is directly formed in the long fiber form, and the non-woven fabric structure is formed in a state in which it is difficult to achieve an undesirably large volume between the substrates for forming the artificial leather, (2) When the long fiber web is subjected to the three-dimensional complexing treatment, the needles of the six needle hooks are used in the needle punching process of the main body, and the filaments are passed through in the thickness direction, and the same is performed over a wide range. In the non-woven fabric structure in which the fibers are in a continuous state and are randomly arranged, the densification and the three-dimensional complexation treatment are performed in an excellent balance without being in a unique fiber arrangement state, thereby forming the non-woven fabric structure. The fiber is laminated on the cross section of the body at a sufficiently high number density, and (3) the water-soluble polymer and the heat-shrinkable polymer are combined as a constituent component of the island-in-the-sea fiber, and the heat shrinkage treatment is performed on the wet Carried out under ambient, non-woven structure to be densified by thermal contraction, the sea component in the instant expansion. Plasticized, the island component can be shrunk to a near-ideal level. However, in order to shrink the fiber diameter of the island component to a near-ideal level, the sea-island fiber is easily shrunk along the fiber axis, which is not easy. Achieving the effect of conventional sea-island fibers by eliminating random riots to eliminate adjacent fibers during shrinkage, and (4) for dissolving and decomposing sea components, due to the molecular size of the more conventional organic solvents Small, polar water as a medium, the diffusion rate of solvent molecules in the sea component polymer is relatively fast, and the state of self-expansion to dissolution is stable, so that the dissolved matter of the sea component polymer is sequentially discharged outside the structure, since it must be applied In the case of a hydraulic or mechanical hard force or the like, the non-woven fabric structure of the present invention which is extremely densified does not enlarge the gap size between the ultrafine fiber bundles, and can easily discharge the components of the sea component decomposition product. , all are the result of being compounded.

In the obtained base material for artificial leather, in order to produce a fluff-like artificial leather which is more uniform in the gap between the ultrafine fiber bundles and has a more compact appearance quality, or a wrinkle-like fine-grained artificial leather In the case of a substrate for artificial leather, it is preferred to apply an extractable polymer solution, an aqueous dispersion or a solution on the surface of the front side of the artificial leather product to harden the easily extractable polymer. The present invention is applied to the surface of the artificial leather product in the rubbing treatment of the subsequent step, in order to obtain a densified non-woven fabric structure which is not conventionally possessed, and at the same time, a smoother and uniform fluff surface can be obtained. Applying an aqueous dispersion of a polymeric elastomer to the surface to make the polymer elastic After the body hardening, when the easily extractable polymer is previously supplied, the article is removed by dissolution or the like. Then, the surface to which the polymeric elastomer is applied is subjected to pressurization and polishing treatment, thereby not only polishing and removing the surface from the original surface to a depth of 20 to 200, but also from the surface after the polishing treatment to about 100 to 300 μm. The depth range allows the nonwoven fabric to be more dense. Further, the polymeric elastomer may be supplied to the surface in advance to smooth the surface or the inside of the substrate for artificial leather by rubbing treatment or calendering treatment. The obtained base material for artificial leather was not only smoothed by the rubbing treatment, but also evaluated that the average void size between the ultrafine fiber bundles from the surface to the range of 200 μm was in the range of 10 to 40 μm, and an extremely uniform dense state was formed.

Examples of the easily extractable polymer, such as polyvinyl alcohol, polyurethane elastomer, acrylic elastomer, polyethylene glycol, paraffin wax, polyethylene wax, and the like. Examples of the polymeric elastomer, such as a polyurethane elastomer or an acrylic elastomer, are the same as those of the polymeric elastomer contained in the nonwoven fabric structure. The coating method of the easily extractable polymer or the polymeric elastomer can be, for example, a conventional gravure coating method, a rotary screen coating method, a spray coating method, a reversible roll coating method, or the like, in which a gravure coating method is used. It is preferred in terms of the balance between the viscosity of the applied liquid and the amount of coating. In the case of the rubbing treatment, the surface of the artificial leather substrate can be observed while the surface of the artificial leather substrate is evaluated by the rubbing treatment by the sandpaper and the pressure level of the sandpaper, and the cross-sectional state of the artificial leather substrate after the treatment is appropriately adjusted and set. At the optimum value.

The obtained base material for artificial leather is cut into several pieces in the thickness direction as needed in the case of producing the artificial leather described above, so that the surface on the inside is advanced. Grinding or the like is performed to adjust the thickness, and the surface of the inner surface or the surface is treated with a liquid containing a solvent of a polymer elastomer or a very fine fiber bundle. Then, at least the surface of the surface is subjected to a raising treatment by a rubbing treatment or the like to form a fiber fluff surface mainly composed of ultrafine fibers, and a fluffy artificial leather such as a fluffy or nubuck leather shape can be obtained. Further, a coating layer formed of a polymeric elastomer is formed on the surface of the surface to obtain a grain-like artificial leather.

When the fiber fluff surface is formed, any conventional method such as rubbing treatment or brushing treatment using sandpaper or card clothing can be used. Further, a solvent which dissolves or expands the polymeric elastomer or the ultrafine fiber bundle before or after the raising treatment, for example, when the polymeric elastomer is a polyurethane elastomer, can be applied to the surface of the raising treatment. When a treatment liquid containing dimethylformamide (DMF) or the like is applied, or when the ultrafine fiber bundle is a polyamide resin, a treatment liquid containing a phenol compound such as resorcin can be applied to the surface of the raising treatment. Thereby, the restraint state of the ultrafine fiber bundle due to the adhesion of the polymeric elastomer or the ultrafine fiber bundle, the ultrafine fiber fluff length of the fluffy artificial leather, the surface friction durability, and the like can be finely adjusted.

In the formation of the coating layer formed of the polymeric elastomer, a method of supplying the liquid containing the polymeric elastomer directly on the surface of the substrate for artificial leather or coating the liquid on a supporting substrate such as a release paper can be used. Any of the conventional methods such as a method of bonding to a substrate for artificial leather. The polymer elastic body used for the coating layer to be formed is a conventional polymer elastic body which is a coating layer of a conventional grain-like artificial leather, as long as it is the same as the polymer elastic body contained in the conventional polymer elastic body. The body can be used, both can be used. When the thickness of the coating layer to be formed is about 300 μm or less, the grain-like artificial leather which is balanced with the sufficient texture of the substrate for artificial leather of the present invention is not particularly limited. When the outer surface of the artificial leather substrate of the present invention is produced, the extremely fine and uniform surface layer of the grain-like artificial leather obtained by forming the dense aggregate state of the ultrafine fiber bundle has a thickness of about 100 μm or less, preferably about The coating layer is formed in a range of 80 μm or less, more preferably about 3 to 50 μm, and by forming the coating layer of the thickness, a grain-like artificial leather having a very fine natural leather-like wrinkle can be obtained.

The pile-like artificial leather or the grain-like artificial leather is dyed in a preferred embodiment at any stage after the sea-island type fiber becomes an extremely elongated fiber bundle. In the present invention, any dye which is appropriately selected, such as a disperse dye, a reactive dye, an acid dye, a metal stinky dye, a sulphur dye, a vulcanization dye, or the like, which is appropriately selected depending on the kind of the optical fiber, may be used, and a pad dyeing machine is used. A dyeing method of a conventional dyeing machine generally used for dyeing a conventional artificial leather such as a jigger, a circular machine, or a dyeing machine. Further, in addition to dyeing, it is mechanically treated in a state of sputum, and a retracting treatment in a wet state such as a dyeing machine or a washing machine, a softener treatment, a flame retardant or an antibacterial agent, and deodorization are performed. Functional imparting treatment such as a functional agent, a water- and oil-repellent agent, a treatment agent for a polyoxyalkylene-based resin or a fibrin-containing resin, a tactile modifier such as a resin for imparting a fixability, a coloring agent, or a coating resin for coating a coating The processing such as the creative imparting treatment of the resin other than the above is preferable. The base material for artificial leather of the present invention has a structure in which the ultrafine fiber bundles are very densely gathered, and is treated in a wet state by a retracting treatment or a softening agent, since the texture can be remarkably improved, and the grain-like artificial leather is selected. Good deal with. For example, in the case of the retracting treatment, by treating the water containing the surfactant in a temperature range of about 60 to 140 ° C, it is possible to obtain a soft feeling, a swelling feeling, and a denseness which are superior to natural leather without deterioration. The artificial leather that has its own sense of fullness will not be damaged.

Next, the embodiments of the present invention will be described by way of specific examples, and the present invention is not limited by the embodiments. Moreover, the parts and % in the examples are not particularly limited and refer to the mass.

(1) Cross-sectional area, number of bundles, and flattening ratio of island-type fibers or extremely thin fiber bundles For any cross section parallel to the thickness direction of the sample, use a scanning electron microscope (about 100 to 300 times) to observe, and randomly select 20 island-in-the-sea fibers that are almost perpendicular to the cross-section from the observation direction, or extremely slender. Fiber bundles. Then, the number of bundles, the flattening ratio, and the projection size of each of the selected sea-island type fibers or the ultrafine fiber bundles are re-observed and obtained as needed to expand by about 1000 to 3000 times. The flatness ratio is determined by the cross-sectional shape of the fiber or the fiber bundle, and the length of the longest portion and the length perpendicular to the length are measured. The former is the value of the longest portion, and the length of the longest portion is usually perpendicular to the thickness direction. length.

Next, regarding the selected 20 island-type fibers or ultrafine fiber bundles, the cross-sectional area is measured, the maximum cross-sectional area and the minimum cross-sectional area are removed, and the remaining 18 cross-sectional areas are calculated by the arithmetic average method to obtain the island type constituting the sample. The cross-sectional area of the fiber, or the ultrafine fiber bundle.

Moreover, the cross-sectional area of the ultrafine fiber bundle refers to the outer circumference of the fiber bundle. The area enclosed by the fibers and the wires connecting the fibers. In addition, when the number of bundles is such that the number of bundles of the respective fiber bundles is not constant and has a distribution, the maximum number of strips and the minimum number are eliminated, and the number of bundles of 18 ultrafine fiber bundles is removed. The number of clusters of the island-type fibers or the number of ultrafine fibers constituting the sample was obtained by an arithmetic average method.

(2) The number density of the island-in-the-sea fiber or the ultra-long fiber of the cross section of the substrate for artificial leather, and the void size and the average void size between the island-in-the-sea fiber or the ultrafine fiber bundle, and any cross section parallel to the thickness direction of the sample, and scanning is used. An electron microscope (about 100 to 300 times) was observed, and a continuous cross-sectional range was observed under a total observation area of about 0.3 to 0.5 mm ² . In the observation direction, when the length of the island-in-the-sea fiber or the number of the ultrafine fibers is almost perpendicular, the number of the determined cross-sections is calculated, and the total number of divisions is divided by the observation area to obtain every 1 mm ^{2 .} The number of island-type fibers or ultrafine fiber bundles present on the top. This observation was performed on at least five observations of one sample, and the minimum value was used as the number density of the sample.

Then, in the same observation direction, all the ranges except the cross-section of the island-in-the-sea fiber or the ultrafine fiber bundle are used as the voids, and the largest circle connected to the sea-island type fiber or the cross section of the ultrafine fiber bundle is drawn, and the circle is measured. diameter. When the gap is continuously present in a wide range, a plurality of circles are drawn without overlapping the circles, and a circle having the largest diameter among the plurality of circles drawn is measured. In addition, the fiber bundles are almost completely adhered to each other in the observation direction, and the partial voids existing under the fiber bundles are removed from the evaluation target in the observation direction. Moreover, in the presence of close contact, it means that it is close to and extremely thin with the constituent fiber bundles. The fiber has a fiber diameter equal to or less than the same. Among the diameters of the measured circles, the maximum value in the observation direction was used as the void size between the ultrafine fiber bundles of the sample. Further, regarding the circle diameter measured by 20 voids which are randomly selected in the observation direction, the arithmetic mean value of 18 of the maximum value and the minimum value is removed as the average gap size between the ultrafine fiber bundles.

(3) Appearance evaluation of fluffy artificial leather The five-person assessor selected by the manufacturer in the field of artificial leather evaluated the appearance of the fluffy artificial leather by visual inspection and the following evaluation, and the evaluation by the most evaluator was used as the evaluation result of the appearance.

A: The density of the surface of the pile is extremely high, and there is no unevenness and extremely smooth when touched by the hand.

B: The compactness of the surface of the pile is slightly thicker, or the density of the whole part is significantly lowered, and the thick part is scattered, and the touch is slightly uneven when touched by the hand.

C: The whole is a thick fluff surface, which is quite uneven when touched by a hand.

(4) Texture evaluation of fluffy artificial leather When the thickness of the obtained fluffy artificial leather is less than 0.8 mm, it is sewn into a golf glove, and when it is 0.8 to 1.2 mm in thickness, it is sewn into a jacket, and when the thickness is more than 1.2 mm, it is sewn into a sofa chair. By wearing a five-person evaluator selected by the manufacturer in the field of artificial leather, the texture of the fluffy artificial leather was evaluated on the basis of the following evaluation, and the evaluation by the most evaluator was used as the evaluation result of the texture.

A: It has a soft, swellable feeling and a feeling of fullness, and the feeling of use of the sewn product is good.

B: The feeling of softness, swelling, and fullness are all slightly insufficient textures. The feeling of use of the product is insufficient (the texture or the feeling of use has the same degree as the conventional fluffy artificial leather).

C: The feeling of softness, swelling, and feeling of fullness is greatly deteriorated, or the texture is greatly deteriorated, and the feeling of use of the sewn product is poor (the texture or the feeling of fullness is more unsatisfactory than the conventional fluffy artificial leather).

(5) Evaluation of surface friction durability of fluff-like artificial leather The surface of the obtained pile-like artificial leather was subjected to a rubbing treatment under the conditions of a load of 12 kPa and a number of rubbing of 50,000 times based on the Martini Lu friction test method specified in JIS L1096. When the mass difference (friction reduction) before and after the treatment was 50 mg or less, it was judged that the abrasion resistance was good. Further, the state of occurrence of peeling of the surface of the pile-like artificial leather before and after the treatment (increase or decrease) was compared by the following criteria. When the abrasion resistance was good and the peeling-producing state was A or B, it was evaluated that the surface friction durability was excellent.

A: No peeling was increased (a decrease in peeling due to cutting of fluff or the like was observed).

B: Although the peeling situation was slightly increased, there was almost no increase in the peeling situation with a hard feeling when touched by the hand.

C: The peeling situation was remarkably increased, and the peeling situation with a hard feeling when touched by a hand was significantly increased.

[Examples] Example 1

Each of the ethylene-modified polyvinyl alcohol (the content of the ethylene unit was 8.5 mol%, the degree of polymerization was 380, and the degree of saponification was 98.7 mol%) as a sea component polymer, and the isophthalic acid as an island component polymer was changed. The polyethylene terephthalate (the content of the isophthalic acid unit is 6.0 mol%) is melted. In a composite spinning nozzle in which a cross section of an island component polymer having 25 uniform cross-sectional areas distributed in a sea component polymer and a plurality of nozzle holes are arranged in parallel, a sea component polymer and an island component polymer in a cross section The average area ratio was supplied to the molten polymer in a pressure ratio of sea component/island component = 25/75, and was discharged from the nozzle hole at a nozzle temperature of 250 °C. Adjusting the pressure of the airflow at an average spinning speed of 3600 m/min. The nozzle type suction device is subjected to a spinning process by stretching and refining the sea-island type fiber having an average cross-sectional area of 177 μm ² (about 2.4 dtex), and sucking the object from the inner side and continuously collecting it on the net. By adjusting the moving speed of the net to adjust the amount of accumulation, and by pressing the embossing roll kept at 80 ° C with a linear pressure of 70 kg / cm, the weight per unit area is 30 g / m ² , and there is a cross section parallel to the thickness direction. A cross-section of 220-250/mm ² island-type fibers, and a long-fiber web having a stable shape up to the extent that it can be taken up.

By spraying an oil agent mainly composed of a mineral oil-based smoothing oil agent and mixing an antistatic agent on the surface of the long fiber web after embossing, the fiber web is continuously folded and formed by using a cross lamination device. 14 layer layered long fiber web. Then, a three-dimensional complexing treatment was carried out by a needle punching method of a needle punching treatment on a layered long fiber fiber web to obtain a non-woven fabric structure having a sea-island type fiber having a number density of 500 pieces/mm ² . The condition of the needling treatment is that the needle number is 40, the depth of the thread is 40 μm, the number of twisted yarns of one needle hook, the needle A of the equilateral triangle section, and the needle punching of the silk thread in the thickness direction from both sides Depth, the depth of the needle punched through the two sides from the twisting direction to the thickness direction is pre-combined, that is, the length of the folded long fiber web is not peeled off, and the knitting needle number is 42 and the depth of the thread is 40μm, the number of twisted yarns with 6 hooks, the needle B of the equilateral triangle cross section, the depth of the needles through which the three needle hooks are threaded in the thickness direction from both sides, and the island-in-the-sea fiber to the desired level and thickness direction Complexation is performed for complexation. The needling treatment of the knitting needle B was carried out from the total number of needles of 1700 needles/cm ² from both sides.

Then, after uniformly spraying and applying water at 18 ° C on both surfaces of the nonwoven fabric structure, secondly, in an environment having a temperature of 75 ° C and a relative humidity of 95%, almost no tension is applied in any direction in the longitudinal direction and the width direction. Under the action of frictional stress, the wet heat shrinkage treatment is carried out under the condition of continuous passage for 4 minutes, so that the island-in-sea type fibers are nearly uniform. Then, before the non-woven fabric structure was dried, it was subjected to a press treatment between metal rolls kept at 120 ° C to compress and smooth the surface, and then dried, and then the entire nonwoven fabric structure was introduced into an environment of 120 ° C to be dried. An extremely dense non-woven fabric structure having a number density of 1,900 g/m ² per unit area and a sea-island type fiber having a number density of 1,900 g/mm ² in a cross section parallel to the thickness direction was obtained.

An aqueous dispersion of a polyurethane composition mainly composed of a polycarbonate elastomer/ether urethane as a polymer elastomer (solid content concentration: 11% by mass) was impregnated into the obtained nonwoven structure. In the non-woven fabric of mass 100, the liquid content of the polymer elastomer liquid is 50, and after pressing with a metal roll, the surface temperature of the nonwoven fabric body is 80 ° C, and the infrared heater is acted upon. The thermosetting treatment was carried out for 1 minute, and finally, the water was dried in an environment of 120 ° C, and then directly introduced into an environment of 150 ° C for hardening treatment for 2 minutes to store the polyurethane composition. It lies in the gap between the island-type fibers. Next, in a liquid flow dyeing machine, it is treated by hot water at 90 ° C for 20 minutes, and the modified polyvinyl alcohol in the sea-island type fiber is extracted and removed, and then the water is dried by introducing the environment at 120 ° C to obtain The non-woven fabric structure formed of the extremely elongated fiber bundle of the modified polyethylene terephthalate contains a polyurethane composition and a base material for artificial leather of the present invention having a thickness of about 1.4 mm.

When observing the extremely thin fiber bundles in the cross section of the obtained substrate for artificial leather, the cross-sectional area is distributed in the range of 200 to 400 μm ² on average of 250 μm ² , so that 25 pieces have an almost uniform fiber diameter and are approximately circular. Very elongated fiber bundles of cross-sectional shape. In the case where the fiber bundle is not flattened in the thickness direction, the flattening ratio of the fiber bundle is at most 2.5, almost all lower than 2.0, and the projection size is 40 μm. Further, the number density of the extremely elongated fiber bundles in the cross section parallel to the thickness direction was 2,500 / mm ² , the gap size between the ultrafine fiber bundles was 52 μm, and the average void size was 35 μm.

Example 2

The base material for artificial leather obtained in Example 1 was divided into two in the thickness direction by the slicing, and the divided surface was rubbed with a sandpaper to have a thickness of 0.67 mm. On the surface which was not subjected to the rubbing treatment, a 6% aqueous solution of polyvinyl alcohol was applied twice with a 55 mesh gravure roll, dried, and then the same polycarbonate/ether as the user of Example 1 impregnated. An aqueous dispersion (solid content concentration: 6 mass%) of a polyurethane-based polyurethane-based composition was applied three times with a 75-mesh gravure roll and dried. The non-embossed sandpaper which is fixed to the surface by the twisting machine is pressed and rubbed to impart fluffing and whole hair to form a fine layer of modified polyethylene terephthalate. The fluff formed by the fibers. Further, after dyeing with a disperse dye using a liquid flow dyeing machine, the bristles were subjected to a bristles treatment to obtain a beige fluffy artificial leather. The obtained fluffy artificial leather has a number density of 2700 pieces/mm ² in the range of 200 μm in the thickness direction from the side of the fluff surface in a cross section parallel to the thickness direction, and the density is extremely high and has a natural similarity. The leather fluffy cow leather has a beautiful fluff appearance, and the texture and surface friction durability are extremely good, and it is a fluff-like artificial leather having the effect of the present invention. The evaluation results are shown in Table 1.

Comparative example 1

In Example 1, except that the island component polymer constituting the sea-island type fiber of the long fiber web was changed to Nylon 6, the sea-island type fiber was spun under an average cross-sectional area of 307 μm ² (about 3.6 dtex). An embossed stabilized long fiber web having a basis weight of 30 g/m ² was obtained in the same manner as in Example 1. On the surface of the obtained long fiber web, an oil agent was applied in the same manner as in Example 1, and then a layered long fiber web was produced by a cross laminator. Next, in the layered long fiber web, the preliminary complexing treatment was performed with the knitting needle A in the same manner as in Example 1, and the knitting needle number was 42, the yarn depth was 40 μm, and the number of the yarns was 1 needle. The knitting needle C of the equilateral triangle cross section, so that the sea-island type fiber is entangled in the thickness direction, and the total number of needles is 3500 needles/cm ² from both sides. deal with. In the obtained nonwoven fabric structure, wet heat treatment and press treatment were carried out in the same manner as in Example 1 to obtain a nonwoven fabric structure having a basis weight of 700 g/m ² .

In the obtained nonwoven structure, in the same manner as in Example 1, the polyurethane composition was present in the void of the sea-island type fiber, and then the modified polyvinyl alcohol in the sea-island type fiber was extracted and removed, and then obtained. The nonwoven fabric structure formed of the extremely long fiber bundle of Nylon 6 contains a base material for artificial leather having a polyurethane composition of about 1.4 mm in thickness. Then, the obtained base material for artificial leather was subjected to a two-division treatment and a rubbing treatment in the same manner as in Example 2 to form a pile formed of a very fine fiber of Nylon 6, and then a liquid dyeing machine was used, and a metal wrong was used. The hydrochloric acid dye was subjected to a dyeing treatment in the same color tone as in Example 2, and a wool-like artificial leather of beige color was produced by performing the entire hair processing. The obtained fluffy artificial leather has an appearance of a rough fluff which can be achieved by a conventional fluffy artificial leather because the density is insufficient, and the surface friction durability is not particularly excellent, and it is impossible to have a texture of a hard and bone texture. The level of the object of the present invention is met. The evaluation results are shown in Table 1.

Comparative example 2

In the first embodiment, the sea-island type fiber which is the sea-island type fiber constituting the long-fiber fiber web is spun, except that the nozzle for composite spinning which can form the cross-section of the polymer having 100 island components is used, and the embodiment 1 An embossed stabilized long fiber web having a basis weight of 30 g/m ² was obtained in the same manner. On the surface of the obtained long fiber web, an oil agent was applied in the same manner as in Example 1, and then a layered long fiber web was produced by a cross laminator. Next, in the same manner as in Example 1, the complexing treatment was carried out by a needle punching treatment. The obtained nonwoven fabric structure was subjected to hot press treatment without applying water to obtain a nonwoven fabric structure having a basis weight of 970 g/m ² .

In the obtained nonwoven structure, the polyurethane composition was present in the void of the sea-island type fiber in the same manner as in Example 1, and the modified polyvinyl alcohol in the sea-island type fiber was extracted and removed, and then obtained. The non-woven fabric structure formed of the extremely elongated fiber bundle of the modified polyethylene terephthalate contains a polyurethane composition and a base material for artificial leather having a thickness of about 1.4 mm. Then, the obtained base material for artificial leather was subjected to a two-part treatment and a rubbing treatment in the same manner as in Example 2 to form a pile formed of ultrafine fibers of modified polyethylene terephthalate, followed by dispersion. The dye is dyed and processed and processed into a wool-like artificial leather. When the obtained pile-like artificial leather was observed to be dense, the fiber bundle of the surface layer portion collapsed and flattened in the thickness direction, and the apparent density did not become too high. When the flattening ratio of the fiber bundle is more than 3.0, the most flattened fiber bundle is 4.7. When the surface portion densified by the flattened fiber bundle is raised by rubbing treatment, it returns to the same compactness as the loose portion which is not densified, and as a result, not only the conventional fluff-like artificial leather can be obtained. The level of coarse fluff that is achieved, and the structure in which the surface layer portion is extremely hard for looseness near the center in the thickness direction, and the texture has a hard feeling on the surface of the corrugated cardboard inside, which cannot satisfy the objective of the present invention. . The evaluation results are shown in Table 1. Further, in comparison with Example 2, since the ultrafine fibers forming the piles are finer, the ones dyed to the same color are whitened, and the colors are not deep, which is a lack of high-grade appearance.

Comparative example 3

In the first embodiment, a composite spinning nozzle which can form a cross section of a polymer having 64 island components is used, and an island having a long fiber web is formed with an average cross-sectional area of 485 μm ² (about 6.6 dtex). A long fiber web having an embossed and stabilized basis weight of 30 g/m ² was obtained in the same manner as in Example 1 except that the sea-island type fiber of the fiber type was spun. On the surface of the obtained long fiber web, an oil agent was applied in the same manner as in Example 1, and then a layered long fiber web was produced by a cross laminator. Next, in the layered long fiber web, the preliminary complexing treatment was performed with the knitting needle A and the knitting treatment with the knitting needle B in the same manner as in the first embodiment. In the obtained nonwoven fabric structure, wet heat treatment and press treatment were carried out in the same manner as in Example 1 to obtain a nonwoven fabric structure having a basis weight of 990 g/m ² .

In the obtained nonwoven fabric structure, in the same manner as in Example 1, the polyurethane composition was present in the void of the sea-island type fiber, and the modified polyvinyl alcohol in the sea-island type fiber was extracted and removed, and then obtained. A base material for artificial leather having a polyurethane composition and a thickness of about 1.4 mm in a nonwoven fabric structure formed of a very long fiber bundle of modified polyethylene terephthalate. Then, the obtained base material for artificial leather was subjected to a two-division treatment and a rubbing treatment in the same manner as in Example 2 to form a pile formed of the ultrafine fibers of the modified polyethylene terephthalate. The dyed processing of the disperse dyes and the processing of the whole hair are carried out to produce a beige-colored artificial leather. The obtained fluff-like artificial leather sufficiently has the number of fiber bundles per unit cross-sectional area and has compactness. However, when the flattening ratio of the fiber bundle is more than 4.0, the void size existing between the fiber bundles may have significant spots. And there are large-sized voids in various places, and as a result, not only the appearance of the rough fluff which can be achieved by the conventional fluff-like artificial leather, but also In the case where the amount of surface friction is small and the peeling situation is clearly increased, there is a small amount of core and a feeling of insufficient swelling feeling, and the level of the object of the present invention cannot be satisfied. The evaluation results are shown in Table 1.

Comparative example 4

In Example 1, the average area ratio of the sea component polymer to the island component polymer divided by the cross section is sea component/island component = 20/80, and the average cross-sectional area is 147 μm ² (about 2.0 dtex). A long fiber web having an embossed and stabilized basis weight of 30 g/m ² was produced in the same manner as in Example 1 except that the sea-island type fiber constituting the sea-island type fiber of the long fiber web was spun. On the surface of the obtained long fiber web, an oil agent was applied in the same manner as in Example 1, and then a layered long fiber web was produced by a cross laminator, and a complexing treatment was carried out by the same needling treatment as in Example 1. The obtained nonwoven fabric structure was immersed in a warm water bath at 70 ° C, subjected to heat shrinkage treatment, and further immersed in a hot water bath at 90 ° C without drying treatment to extract and remove the modified polyvinyl alcohol in the sea-island type fiber. Thus, a base material for artificial leather which was formed of a very long fiber bundle of modified polyethylene terephthalate and which did not contain a polyurethane composition and had a basis weight of 845 g/m ² was obtained.

Then, the obtained base material for artificial leather was subjected to a two-division treatment and a rubbing treatment in the same manner as in Example 2 to form a pile formed of ultrafine fibers of polyethylene terephthalate, and then The dyeing processing of the disperse dyes and the processing of the whole hair are made into beige fluffy artificial leather. The obtained fluffy artificial leather is different from the other examples, and has a solid feeling of solidity regardless of the absence of the polyurethane composition. However, when observing the cross section, it was found that the portion where the fiber bundle is very densely packed and the slightly loose portion are mixed, so that the surface of the fluff formed by the rubbing treatment in the fiber bundle of the fiber bundle is the number of fluff from the spot. Many parts are mixed with less parts. When the number density of the extremely thin fiber bundles in the cross section parallel to the thickness direction is evaluated, the number of the vicinity of the surface is 1400/mm ² , the gap size between the ultrafine fiber bundles is 74 μm, and the average void size in the range from the surface to 200 μm. It is 42 μm. As a result, the whole has a rough fluff appearance and does not have the level of meeting the object of the present invention. The evaluation results are shown in Table 1.

Comparative Example 5

In the first embodiment, in addition to the sea-island type fiber constituting the long fiber web, five layers of a polymer capable of forming a component (sea component polymer) and six layers of a fiber component polymer (corresponding to an island component polymer) are overlapped. a nozzle for composite spinning having a cross-sectional shape of overlapping shape, the same ethylene-modified polyvinyl alcohol as in Example 1 as a component-removing polymer, and the same isophthalic acid-modified poly(terephthalic acid) as in Example 1. The ethylene glycol is separately melt-treated as a fiber component polymer. The molten polymer was supplied under a pressure balance of an average area ratio of the component-removing polymer of the cross section to the fiber component polymer of the removal component/fiber component = 35/65, and the average cross-sectional area was 330 μm ² (about 4.4 dtex). In the same manner as in Example 1, except that the sea-island type fiber was spun, a long fiber web having an embossed stability of 30 g/m ² per unit area was obtained. On the surface of the obtained long fiber web, an oil agent was applied in the same manner as in Example 1, and then a layered long fiber web was produced by a cross laminator. Next, in the layered long fiber web, the preliminary complexing treatment was carried out with the knitting needle A in the same manner as in Example 1, and the knitting needle number was 32, the yarn depth was 60 μm, and the number of the yarns was 9 needles. The needle D of the equilateral triangle section is used to make the composite fiber penetrate the thickness in the thickness direction, and the composite fiber is complexed in the thickness direction, and the total number of needles of 600 needles/cm ² is complexed from both sides. (When needle punching is performed with acupuncture D and needle punching of more than 1000 needles/cm ² , most of the problems such as needle breakage occur), and secondly, the needle number is 36 and the thread depth is 80 μm. The needle E of one needle hook and the needle E of the equilateral triangle section were needle-punched at a needle punching depth of 400 needles/cm ² without a needle penetration depth in which the thread was penetrated in the thickness direction. After the needle-punching treatment with the knitting needle E, when the non-woven fabric structure is observed, the cross-section is mostly a fiber bundle that is needle-punched and oriented in the thickness direction, and the end of the fiber due to the cutting is observed on the surface. It is a frequency of 0.5 to 2.5 strips/mm ² . In the obtained nonwoven fabric structure, wet heat treatment and press treatment were carried out in the same manner as in Example 1 to obtain a nonwoven fabric structure having a basis weight of 650 g/m ² .

In the obtained nonwoven structure, the polyurethane composition was present in the void of the sea-island type fiber in the same manner as in Example 1, and then the modified polyvinyl alcohol in the sea-island type fiber was extracted and removed, and then obtained. The nonwoven fabric structure formed of the extremely elongated fiber bundle of the modified polyethylene terephthalate contains a polyurethane composition and a base material for artificial leather having a thickness of about 1.4 mm. Then, the obtained base material for artificial leather was subjected to a two-division treatment and a rubbing treatment in the same manner as in Example 2 to form a pile formed of the ultrafine fibers of the modified polyethylene terephthalate. The dyed processing of the disperse dyes and the processing of the whole hair are carried out to produce a beige-colored artificial leather. In the obtained fluff-like artificial leather, when the cross section is observed, the denseness of the fiber bundle is not only significantly deteriorated as compared with Example 1, but also in the fiber. There are significant spots in the gap between the bundles, and there are large gaps everywhere. Therefore, it is not only impossible to obtain the appearance of the rough fluff which can be achieved by the conventional fluff-like artificial leather, and has a very hard bone feeling. The texture does not meet the level of the object of the present invention. The evaluation results are shown in Table 1.

[Utilization value of industry]

The artificial leather obtained by using the base material for artificial leather of the present invention can be suitably used for clothing made of a jacket or a skirt, a shirt or a jacket, because of its high level of appearance, surface strength, texture and the like. Sneakers or gentlemen's women's shoes for typical shoes, belts for typical clothing, handbags or student backpacks for typical bags, sofas or desks for furniture, for cars or Trains, airplanes, or ships are used for sheets or interior materials of typical transportation tools, sports gloves such as golf gloves, banquet gloves, baseball gloves, etc., and gloves for driving, and gloves for work are typical for various types of gloves. .

The pile-like artificial leather obtained from the substrate for artificial leather of the present invention has extremely high density and has an appearance of a fluffy texture such as natural fluffy leather. Further, it is excellent in color developability, has a feeling of softness and a feeling of fullness, and is excellent in properties such as surface friction durability which is typically excellent in peeling resistance. Moreover, the grain-like artificial leather obtained from the base material for artificial leather of the present invention has high smoothness and has an appearance of a grainy texture of natural leather such as wrinkles. Further, it has excellent properties such as a texture of the base material and the grain surface layer, a feeling of softness, a feeling of expansion, and a strong peeling strength. These artificial leathers are suitable for use in various sports gloves such as clothing, shoes, handbags, furniture, car seats, golf gloves, and the like.

Claims (7)

A base material for artificial leather, which is a base material for artificial leather composed of a non-woven fabric structure of extremely thin fiber bundles, and is characterized by satisfying the following (1) to (4): (1) extremely elongated fiber bundle system 8 to 70 bundles of extremely thin fibers having a cross-sectional shape of approximately circular shape, (2) a very elongated fiber bundle having a cross-sectional area of 170 to 700 μm ² and a flatness ratio of 4.0 or less, and (3) a non-woven structure. In any cross section in which the thickness direction is parallel, the cross section of the extremely thin fiber bundle is in the range of 1500 to 3000 pieces/mm ² , and (4) the gap between the ultrafine fiber bundles in any cross section parallel to the thickness direction of the nonwoven fabric structure. The size is 70 μm or less. The substrate for artificial leather according to the first aspect of the invention, wherein the average gap size between the ultrafine fiber bundles is in the range of 10 to 40 μm from the surface of any cross section parallel to the thickness direction of the nonwoven fabric structure to 200 μm. . A substrate for artificial leather according to claim 1 or 2, which comprises a polymeric elastomer. A pile-like artificial leather characterized by being formed by raising the surface of a substrate for artificial leather according to any one of claims 1 to 3. A method for producing a substrate for artificial leather, which is a method for producing a substrate for artificial leather according to any one of claims 1 to 3, characterized in that the following steps (a) to (d) are sequentially carried out, (a) The island component is made of a heat-shrinkable polymer, and the sea component is a water-soluble polymer. The number of islands is 8 to 70, and the cross-sectional area ratio of sea to island is 5:95 to 60:40, and the cross-sectional area is 70~. 350 μm ² of island-in-the-sea long fiber is subjected to melt spinning treatment, so that the material is aggregated in a random alignment state on the collecting surface without being cut, to produce a sheet-like long fiber web, (b) The long fiber web is subjected to acupuncture from both sides by using at least six needle-wound needles and at least one needle of the needles to be penetrated according to the required overlapping combination of the long fiber webs. a step of three-dimensionally complexing the island-in-a-sea long fibers with each other to produce a non-woven fabric structure, and (c) performing a wet heat treatment on the non-woven fabric structure under the condition that the sea component polymer is plasticized and the island component polymer is shrunk, and Heat-pressing as needed, densifying to a section parallel to the thickness direction That the sea-island long fibers is 1000 to 3500 pieces / mm ² up to the range of the step, (d) water or aqueous solutions by removal of the sea component from the sea-island filaments to step into the bundle of elongated electrode. A method for producing a substrate for artificial leather, which is characterized in that the following steps (e) to (h) are sequentially carried out as a step (d) in the method for producing a substrate for artificial leather according to item 5 of the patent application; a step of (e) applying a solution, an aqueous dispersion or a solution of an extractable polymer on at least one side of the non-woven structure, and hardening the extractable polymer, (f) a step of applying an aqueous dispersion of a polymeric elastomer to the same surface and curing the polymeric elastomer, (g) removing the extractable polymer from the nonwoven structure, and (h) pressing, The surface of the polymer elastic body is surface-coated and densified to a range of 200 μm from the surface of the grinding treatment side of any cross section parallel to the thickness direction of the nonwoven fabric structure, and the average gap size between the ultrafine fiber bundles is 10 Steps in the range of ~40 μm. A method for producing a substrate for artificial leather, characterized in that the following step (i) is carried out as a step before or after the step (d) in the method for producing a substrate for artificial leather according to claim 5 or 6 (i) A step of impregnating a non-woven structure with a solution or an aqueous dispersion of a polymeric elastomer and curing the polymeric elastomer.