JP2006045737A - Artificial leather having excellent shape stability and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an artificial leather, comprising producing a uniform fiber laminate interlacement product not causing bends, wrinkles and basis weigh irregularity and then using the fiber laminate interlacement product to produce the artificial leather, by which the artificial leather having excellent shape stability enabling the control of longitudinal elongation and the like in the production process and giving a good hand not hardened. <P>SOLUTION: This method for producing the artificial leather comprising a fiber interlacement product and a polymer elastomer imparted into the fiber interlacement product is characterized by sequentially performing the following processes (1) to (4). (1) A process for laminating a staple fiber web to a woven or knitted fabric capable of being substantially extracted away with water, and then subjecting the laminated product to an integrally interlacing treatment to produce the fiber laminated interlacement product, (2) a process for thermally shrinking the fiber laminated interlacement product, (3) a process for imparting a polymer elastomer into the fiber laminated interlacement product, and (4) a process for extracting the woven or knitted fabric with water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  By producing artificial leather via a fiber laminate entangled body, the present invention makes it possible to make the resulting artificial leather folds, wrinkles and uneven spots, and to achieve longitudinal elongation in the production process. Therefore, the present invention provides an artificial leather that has excellent shape stability and good texture due to suppression of curing.

Conventionally, artificial leather has been developed mainly consisting of ultrafine fibers and polymer elastic bodies. Artificial leather made of such ultrafine fibers is superior in suede, surface touch and flexibility. It has been highly evaluated as a material similar to natural leather. In addition, in the manufacture of artificial leather, it has been proposed to improve the texture, increase the fiber density and strength, or provide bulkiness and stretchability by applying a shrinkage treatment.
Moreover, as a method for forming the fiber entangled body, a needle punch method is generally used. That is, it is a method in which a needle is repeatedly inserted into a fiber web, and the fiber is hooked and entangled with a barb on the side surface of the needle or a recessed portion attached to the needle tip. However, even if a general fiber web is previously spread evenly with a cross wrapper, random web, gas-liquid flow, etc. and then overlapped, the nonwoven fabric is compared with the basis weight at the center in the width direction of the nonwoven fabric made of fiber web during needle punching. There was a tendency for the fabric weight at both ends in the width direction to become higher.
In addition, when passing through various processes in the manufacture of artificial leather, a large amount of tension is applied in the vertical direction, making it easy to stretch in the vertical direction. In addition, when finished in a suede-like artificial leather, there was a problem that the fluff density in the surface appearance was reduced or its spots were generated, and the obtained artificial leather was liable to have a low form stability.

  Many proposals have been made to solve these problems. For example, a raw fiber supply apparatus configured to prevent spot weight without reducing the spinning amount has been proposed (see, for example, Patent Document 1). However, although this apparatus improves the unevenness of the fiber web, it has not yet improved the unevenness of the fiber due to the shape change in the needle treatment. In addition, as a measure for improving spot weight generated during needle processing, a short needle that can entangle fibers and a long needle that does not substantially entangle the fibers or that is ½ or less of the entanglement capability of the short needles. And a method of needle punching a fiber web has been proposed (see, for example, Patent Document 2). However, long needles tend to bend, bend, and easily cause needle streaks in the resulting fiber entanglement, and the fiber entanglement tends to increase in elongation. Separately from the above method, 0.01 to 1.0% by weight of the oil agent is attached to the short fiber web while controlling the web in the width direction so that the end portion is less than the center portion. There has even been proposed a method of improving the spot weight that occurs during needle processing by applying a needle punch (for example, Patent Document 3). However, in this method, not only the oil agent is applied at the time of producing the short fibers, but the oil agent must be applied again at the time of laminating the web, which is troublesome, and the oil agent is easily applied to the surface layer of the web. It was difficult to uniformly adhere in the thickness direction, and it was difficult to say that it was sufficiently satisfactory in improving the spot weight.

On the other hand, a fiber web made of fibers that can be made ultrafine and a knitted fabric are entangled and integrated by entanglement, and then subjected to treatment including ultrafine treatment, polymer elastic body application treatment, and napping treatment. Regarding a method for producing a sheet obtained, a method for producing artificial leather excellent in stretchability that removes a knitted fabric after shrinking in a length direction and / or a width direction by performing a heat treatment, and also includes ultrafine fibers A shrinkable sheet that shrinks 10% or more in the length direction by shrinkage treatment is bonded to the surface of at least one side of an artificial leather composed of a fiber entangled body and a polymer elastic body. There have been proposed methods for producing artificial leather with excellent stretchability that removes water (for example, Patent Document 4 and Patent Document 5). However, although these methods are effective in terms of form stability, mechanical removal processing such as buffing must be performed when the woven or knitted fabric to be inserted is finally removed, which is troublesome. The adjustment of the buffing process becomes difficult, and the surface is easily roughened unnecessarily, or the tension is easily applied in the processing direction by passing an extra step. Furthermore, there were many very useless parts regarding manufacturing costs.
In addition, if the woven or knitted fabric to be inserted is composed of components that can be extracted with a solvent, the surface of the product will not be unnecessarily roughened by extracting the solvent, but the product may be removed by repeated nip treatment during the extraction of the solvent. The feeling of swelling was impaired and the texture of the product was inferior.
As described above, the conventional technology has not yet realized what is sufficiently satisfied with respect to form stability and texture, such as suppressing the uneven appearance of the fiber entangled body and extending longitudinally when passing through each process in the production of artificial leather. .

Japanese Patent Laid-Open No. 11-247032 (page 1-3) JP-A-48-53062 (pages 367-370) JP 2000-265350 A (page 1-5) JP 2003-13368 A (page 1-3) JP 2003-89983 A (page 1-5)

  By producing artificial leather via a fiber laminate entangled body, the present invention makes it possible to make the resulting artificial leather folds, wrinkles and uneven spots, and to achieve longitudinal elongation in the production process. Therefore, the present invention provides an artificial leather that has excellent shape stability and good texture due to suppression of curing.

That is, the present invention provides a method for producing artificial leather, characterized in that the following steps (1) to (4) are sequentially performed when producing an artificial leather in which a polymer elastic body is provided inside a fiber entangled body. It is.
(1) The process of manufacturing a fiber lamination entangled body by carrying out an entanglement integration process, after laminating | knitting the woven / knitted fabric which consists of a fiber which can be substantially extracted by water extraction with a short fiber web,
(2) a step of thermally shrinking the fiber laminate entangled body,
(3) A step of providing a polymer elastic body inside the fiber laminate entangled body,
(4) a step of extracting and removing the woven or knitted fabric with water,
Further, it is preferable that the short fiber web is an ultra-fine fiber generating fiber composed of a water-soluble polymer component and a poorly water-soluble polymer component, and the water extractable / removable fiber constituting the woven or knitted fabric is α- having 4 or less carbon atoms. It preferably comprises a modified polyvinyl alcohol containing 1 to 20 mol% of olefin units and / or vinyl ether units and having a saponification degree of 90 to 99.99 mol%.
Moreover, this invention is the artificial leather obtained by the above-mentioned manufacturing method, and also is a suede-like artificial leather obtained by carrying out raising treatment of this artificial leather.

Hereinafter, the present invention will be described in detail.
The present invention relates to a production method for producing a fiber laminated entangled body by entangled and integrating a short fiber web and a woven or knitted fabric that can be extracted by water extraction, and suppressing the thickness unevenness and the unevenness of the artificial leather obtained. is there. Moreover, it is related with the manufacturing method which suppresses the longitudinal elongation of the artificial leather at the time of a process by manufacturing artificial leather via this fiber lamination entanglement body. That is, when forming the fiber laminate entangled body, the inserted woven or knitted fabric does not cause uneven spots between the center portion and both end portions of the fiber laminate entangled body, and a uniform fiber laminate entangled body can be produced. In addition, the insertion of the woven or knitted fabric enables the longitudinal elongation to be suppressed in the fiber laminate entanglement manufacturing process, the heat shrink process, or the subsequent artificial leather manufacturing process, and does not impair the quality of the artificial leather. Excellent in properties. Furthermore, after the polymer elastic body is impregnated, the inserted woven or knitted fabric can be removed only by water extraction without grinding and without solvent extraction, thereby softening the texture and reducing the surface quality. The leather can be manufactured.

The short fiber constituting the fiber entangled body of the present invention may be either a fiber obtained by direct spinning or a fiber obtained from an ultrafine fiber generating fiber, but from the viewpoint of spinning stability, an ultrafine fiber generating fiber It is preferable that In particular, the fineness after the ultrafine fiber is preferably 0.0003 to 0.4 dtex, more preferably 0.003 to 0.2 dtex, and even more preferably 0.007 to 0.1 dtex. A fiber generating fiber is preferred. As the fineness of such an ultrafine fiber-generating fiber, a range of 1 to 15 dtex is preferable in terms of excellent processability after spinning.
It is important that the short fiber has an average fiber length of 18 to 110 mm. If the fiber length is 18 mm or more, effective entanglement is possible, and if the fiber length is 110 mm or less, the process passability such as card processing is excellent. However, when post-processing such as slicing or buffing is performed thereafter, the short fibers may be cut before reaching the final product, and some fibers that are less than 18 mm may be included. Since the fibers are generated after effective entanglement is achieved, the effect of the present invention is not impaired. In addition, the average fiber length is more preferably 20 to 80 mm from the viewpoint of the process passability.

  The ultrafine fiber generating fiber is preferably composed of a water-soluble polymer component and a poorly water-soluble polymer component from the viewpoint of environmental friendliness. The water-soluble polymer component indicates a component from which the component is extracted and removed by an aqueous solution, and the poorly water-soluble polymer component indicates a component that is difficult to extract and remove by an aqueous solution. And, as long as at least one component is extracted and removed by water extraction treatment with an aqueous solution, an ultra-fine fiber generation type fiber composed of a water-soluble polymer component and a poorly water-soluble polymer component is a sea-island type composite fiber, a mixed spinning type fiber, etc. Any of the multicomponent composite fibers may be used. As the water-soluble polymer component used in the present invention, a known polymer can be used as long as it is a polymer that can be extracted with an aqueous solution (sometimes referred to as an aqueous solvent). Polymers (hereinafter sometimes abbreviated as PVA) are preferably used. PVA can be easily dissolved and removed with water, especially hot water, and the structure of crimping is very high due to the shrinkage behavior when it is extracted and removed with an aqueous solvent. It is dense and can produce artificial leather with an excellent texture like natural leather, and the decomposition and dissolution reaction of ultra-fine fiber components and polymer elastic body components is practical during water extraction treatment. Therefore, the thermoplastic resin and the polymer elastic body component used for the ultrafine fiber component are hardly limited, and they are preferably used from the viewpoint of environmental considerations.

The PVA may be a homopolymer or a modified polyvinyl alcohol introduced with a copolymer unit. However, from the viewpoints of melt spinnability, water solubility, fiber properties, and shrinkage characteristics during extraction processing, the copolymer unit may be Preferably, the introduced PVA is an α-olefin having 4 or less carbon atoms such as ethylene, propylene, 1-butene, isobutene, methyl vinyl ether, ethylene vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether. More preferred are vinyl ethers such as Moreover, it is preferable that 1-20 mol% of units derived from α-olefins having 4 or less carbon atoms and / or vinyl ethers are present in PVA. Furthermore, when the α-olefin is ethylene, the fiber physical properties are improved, and therefore, it is more preferable to use PVA in which 4 to 15 mol% of ethylene units are particularly modified.
The saponification degree is preferably 90 to 99.99 mol%, more preferably 92 to 99.98 mol%, further preferably 94 to 99.96 mol%, and particularly preferably 95 to 99.95 mol%. When the saponification degree is less than 90 mol%, the thermal stability of PVA is poor and satisfactory composite melt spinning cannot be performed by thermal decomposition or gelation. On the other hand, PVA having a saponification degree larger than 99.99 mol% is difficult to produce stably.
In addition, when PVA of the type that elutes into water at room temperature is used as the water-soluble polymer component, the water-soluble polymer component may elute during impregnation and contaminate the polymer elastic water dispersion. Because the polymer elastic body impregnated by exposing the ultrafine fiber part due to partial elution of the functional polymer component directly binds the ultrafine fiber and the texture of the artificial leather is hard and easily damaged, the hot water at 60 to 100 ° C. It is preferable to use an elution type PVA as the water-soluble polymer component. Furthermore, by eluting the water-soluble polymer component with hot water at 60 to 100 ° C., the shrinkage behavior of the fiber entanglement occurs and the structure is easily crimped, so that an artificial leather base having an excellent texture similar to that of natural leather can be obtained. This is preferable.

In addition, since spinning of PVA at a high temperature causes deterioration of spinnability, the poorly water-soluble polymer component of the present invention can be a known ultrafine fiber. For example, it is particularly limited as long as it is a component such as polyamide, polyester and polyolefin Not what you want. The melting point of the poorly water-soluble polymer component constituting the ultrafine fiber is preferably selected as appropriate, and the poorly water-soluble polymer component constituting the ultrafine fiber is a water-soluble polymer extracted and removed in the process of forming the ultrafine fiber. From the viewpoint of spinning stability of the ultrafine fiber generating fiber, it is preferable to select a thermoplastic component having a melting point between 60 ° C. and the melting point of the component. For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate copolymerized with isophthalic acid, polyester resin typified by polybutylene terephthalate copolymerized with isophthalic acid, or nylon 6, nylon 11, nylon 12, etc. Polyamide resins are preferred. The melting point of the water-soluble polymer component is preferably 160 to 230 ° C. from the viewpoint of spinnability.
In addition, as a mass ratio of the water-soluble polymer component and the hardly water-soluble polymer component constituting the ultrafine fiber-generating fiber, the range of water-soluble polymer component / little water-soluble polymer component = 10/90 to 60/40 is When cross-section is good and water-soluble polymer is easy to completely cover ultrafine fibers, uniform penetration inside the fiber entangled body is obtained, which is advantageous for uniform impregnation, or when artificial leather base is used Since the cross-sectional formability is good, the fine fibers generated are uniform, which is preferable in that the texture of the resulting artificial leather is not impaired.

The fiber constituting the short fiber of the present invention may contain a pigment. In this case, if the final product needs a light-colored system, that is, a color developability as a light color or a light color, a small amount of pigment is required, and the addition of the pigment inside the ultrafine fiber is at a low concentration. That is, when the color of the appearance required as the final product is light, the amount of pigment added to the inside of the ultrafine fibers is preferably 0 to 1% by mass, and in the case of medium color, 1 to 2% by mass is preferable, and the dark color In this case, the content is preferably 2 to 5% by mass, and if it exceeds 5% by mass, the spinning processability is inferior, the fiber strength is lowered, and the resulting tear strength of the artificial leather is inferior.
As the pigment to be used, for example, inorganic pigments such as titanium oxide, carbon black, chrome red, and molybdenum red, and organic pigments such as phthalocyanine-based and anthraquinone-based organic pigments that are usually used for polymer deposition can be used. In particular, when carbon black is used, the average primary particle size of carbon black is determined from the fact that carbon black is mixed and integrated in the polymer constituting the ultrafine fiber and is easily embedded in the polymer constituting the ultrafine fiber. Is preferably 10 to 60 nm. When the average primary particle size of the carbon black is less than 10 nm, it is difficult to obtain uniform fibers due to the tendency of the carbon black to aggregate during spinning, and the quality stability of color spots, physical spots, etc. This problem tends to occur, and the spinnability tends to decrease. Conversely, when the average primary particle size of carbon black exceeds 60 nm, when the resulting artificial leather is suede, the light fastness and color developability tend to decrease, and the filter is clogged during the spinning process. Tends to occur and the spinnability tends to decrease. Carbon black generally exists as an aggregate of a plurality of primary particles (hereinafter referred to as an aggregate), but carbon black is present in a mixed and integrated manner in the polymer constituting the ultrafine fiber, and mainly contains the ultrafine fiber. The average particle diameter of the aggregate is more preferably 20 to 200 nm because it is easily embedded in the polymer constituting it and has good color developability, light fastness and spinnability. In addition, in other inorganic pigments and organic pigments, the average particle size is more preferably 20 to 200 nm for the same reason.
In addition, as a method for adding the pigment, in order to improve the dispersibility of the pigment in the polymer constituting the ultrafine fiber, the polymer and the pigment constituting the ultrafine fiber are kneaded using a compound facility such as an extruder and then pelletized. It is preferable to adopt the master batch method. In addition, a stabilizer such as a copper compound, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a flame retardant, and a plasticizer are included in the ultrafine fiber component as long as the purpose and effect of the present invention are not impaired. Further, a lubricant and a crystallization rate retarder may be added during the polymerization reaction or in the subsequent steps. The type of fine particles is not particularly limited, and for example, inert fine particles such as silica, alumina, titanium oxide, calcium carbonate, and barium sulfate can be added. These may be used alone or in combination of two or more. In some cases, spinnability and stretchability may be improved.

The above-mentioned ultrafine fiber-generating fiber is usually drawn after spinning, but may be drawn once after being discharged from the spinning nozzle and then drawn, or may be drawn before winding, and any method may be used. The stretching method is usually hot stretching, but may be performed using any of hot air, a hot plate, a hot roller, a water bath, and the like. However, when one component of the ultrafine fiber-generating fiber is a water-soluble polymer component, it is preferable to draw with hot air that is less affected by moisture.
In the present invention, it is necessary to suppress the longitudinal elongation at the time of passing through the manufacturing process in order to improve the unevenness of the artificial leather and the unevenness of the thickness of the artificial leather, and further improve the shape stability without impairing the quality of the artificial leather. Therefore, it is necessary to insert a woven or knitted fabric. At that time, it is important to use a knitted or knitted fabric that can easily form a monolithic structure with the short fibers because the shape stability becomes good. Further, in the production of artificial leather, it is necessary that a polymer elastic body is provided inside the fiber entangled body. However, since the polymer elastic body directly holds the woven or knitted fabric without voids and hardens the artificial leather, in the present invention, In order to suppress the hardening of the leather, it is necessary that the fiber can be easily removed by water extraction. If water extraction is not possible, when removing the woven or knitted fabric, it must be treated by grinding such as buffing, and the surface condition may be unnecessarily roughened, and the surface appearance of the product may be greatly impaired. Short fibers that do not need to be ground must be ground, increasing the overall grinding amount and increasing the cost. Or if it is a woven or knitted fabric that can be extracted with a solvent, it is necessary to repeat the dip / nip process when removing the solvent, and it takes a lot of time, and the repeated dip / nip process compresses the artificial leather, resulting in a feeling of swelling. It will be chipped and inferior in texture.

The fiber constituting the woven or knitted fabric needs to be a fiber that can be substantially extracted by water extraction, and the water extraction component used at that time is a polymer that can be extracted with an aqueous solution (sometimes referred to as an aqueous solvent). In this case, known polymers can be used, but it is preferable to use polyvinyl alcohol copolymers (hereinafter sometimes abbreviated as PVA) that are soluble in an aqueous solvent, and are used for short fiber webs as described above. PVA is preferred.
Furthermore, when the ultrafine fiber that forms the short fiber uses a water-soluble polymer component, it is the same as the water-soluble polymer component that forms the woven or knitted fabric. Well, it is more preferable in that it suppresses the deterioration of texture and the occurrence of spotted spots caused by applying an unnecessary load.
Further, the woven or knitted fabric composed of the above-mentioned fibers of the present invention preferably forms 10 to 650 T / m, more preferably 15 to 500 T / m, as the number of twists of the woven or knitted fabric in order to form an integral structure with the short fiber web. . If it is less than 10 T / m, the single yarn of the knitted or knitted fabric is completely scattered when entangled with the short fiber web, and the damaged yarn is greatly exposed to the surface. Since the woven or knitted fabric is finally extracted and removed, the woven or knitted fabric itself does not affect the appearance of the product. It is likely to occur and as a result, the appearance may be deteriorated. When the twist number exceeds 650 T / m, it is difficult to obtain an integrated structure in which the short fibers and the woven or knitted fabric are entangled strongly, and when the shrinkage difference occurs between the short fibers and the woven or knitted fabric, the fiber entangled body is wrinkled. In addition, there is a texture difference due to a difference in shrinkage, and the product after extraction and removal of the woven or knitted fabric becomes non-uniform, which is inappropriate for obtaining a texture of natural leather-like. The woven or knitted fabric basis weight can be set as appropriate depending on the purpose, is preferably ^{20~200g / m 2, 30~150g / m} 2 is more preferable. If the basis weight is less than 20 g / m ² , the shape of the woven or knitted fabric becomes very loose, and the shape stability of the woven fabric such as misalignment is lacking. If the basis weight exceeds 200 g / m ² , the woven or knitted fabric becomes dense, and the woven or knitted fabric becomes dense. The penetration of the woven web is insufficient, and high entanglement does not progress, making it difficult to produce a structure that is separated and integrated. As the types of woven and knitted fabrics, weft knitting represented by warp knitting and tricot knitting, lace knitting and various knittings based on these knitting methods, or plain weaving, twill weaving, satin weaving and weaving these The various woven fabrics are not particularly limited. Which one to select, such as tissue or density, may be determined appropriately according to the purpose.

And it can entangle using a well-known method as a fiber lamination entanglement body of this invention. For example, the ultrafine fiber generating fiber obtained above is first crimped and then stapled, and a short fiber web is formed by a card, a cross wrapper, a random weber, or the like. Then, the woven or knitted fabric composed of the fibers that can be substantially removed by water extraction is laminated on the surface layer, the lower layer, or the intermediate layer of the short fiber web, and the fibers are entangled by needle punching. The needle punching condition is preferably such that the needle needle barb penetrates to the surface of the laminate and the number of needle punches is 400 to 5000 punch / cm ² , more preferably 1000 to 2000 punch / cm ² . It is a condition. Needle punching is preferably performed from both sides of a laminate in which a nonwoven fabric and a woven or knitted fabric are overlapped from the viewpoint of obtaining an appearance for natural leather. That is, it is preferable in that it is easy to obtain a fiber laminated entangled body having a monolithic structure in which the reinforcing knitted fabric constituting fibers are exposed on the surface side of the nonwoven fabric and the nonwoven fabric constituting fibers are exposed on the surface side of the woven or knitted fabric. .

  The obtained fiber laminate entangled body needs to be subjected to shrinkage treatment in order to increase the fluff density of the fiber by heat shrinking the fiber laminate entangled body to obtain a good texture, and may be hot pressed as necessary. Preferably, the area of the fabric is reduced to 40 to 90% before shrinkage by this shrinkage treatment. This shrinking treatment provides a dense structure, and the shrinkage is so low that the degree of shrinkage is 90% or more of the area before shrinkage, the feeling of denseness is not obtained, and the texture is deteriorated. Conversely, less than 40% of the area before shrinkage In the case of such large shrinkage, the texture is hardened, which is not preferable. The shrinkage treatment is preferably performed by leaving the entangled body in an atmosphere of 160 to 200 ° C. for 0.5 to 3 minutes. In addition, as described above, when there is a shrinkage difference between the short fiber and the woven or knitted fabric in the shrinking treatment, wrinkles may occur in the fiber entangled body. However, when the woven or knitted fabric has an integral structure, wrinkles are generated. There is an advantage that it can be suppressed, and further, the woven or knitted fabric suppresses the longitudinal elongation due to the longitudinal tension during the process passage, and the shrinkage not only in the transverse direction but also in the longitudinal direction is enabled, so that excessive shrinkage only in the transverse direction is suppressed. It becomes easy to shrink uniformly, and accordingly, it is possible to suppress the occurrence of thickness spots and spotted spots.

  The surface exposure degree of each single fiber constituting the woven or knitted fabric, that is, the surface exposure degree of each single fiber constituting the woven or knitted fabric is 0 on the surface opposite to the woven or knitted fabric between the woven and knitted fabric and the nonwoven fabric composed of short fibers. It is preferably 3 to 20%, more preferably 1 to 15%, still more preferably 2 to 10%. If it is less than 0.3%, the entangled state of the short fiber and the woven or knitted fabric is weak, and unlike an entangled body having a tightly entangled integral structure, wrinkles are likely to occur during shrinkage. On the other hand, if it exceeds 20%, a fiber laminated entangled body having a tightly entangled monolithic structure can be obtained, but the appearance tends to deteriorate, and the damage to the woven or knitted fabric is great, so the appearance in the final product after extraction of the woven or knitted fabric Tends to decrease.

In addition, the evaluation method of the surface exposure degree said by this invention is demonstrated next.
<Embedded paraffin under reduced pressure>
Paraffin mp68-70 ° C
Hot plate uchi NHP-1
<Microtome>
Device HM360 manufactured by MICROM
<Microscope>
Device SMZ1000 manufactured by Nikon
<Method>
1) The entangled integrated product of the obtained nonwoven fabric (A) and woven or knitted fabric (B) is embedded in reduced-pressure paraffin (approximately 80 ° C., aspirator reduced pressure). Of course, a polymer elastic body may be provided.
2) Cut about 100μ from the surface with a microtome.
3) Magnify 100 times with an optical microscope, and further magnify it 2 times and take a picture 4) Perform image analysis with a personal computer, and the area of the woven / knitted fabric fibers on the nonwoven fabric (A) side (P) is measured. (1cm x 1cm)
Surface exposure degree = 100 × P / (nonwoven fabric constituting fiber composed of short fibers + woven fabric constituting fiber) area The method of obtaining the denominator (nonwoven fabric constituting fibers composed of short fibers + woven fabric constituting fibers) area is as follows: The occupation ratio of the constituent fibers is obtained from the apparent density and the specific gravity of the fiber-entangled constituent fibers, and the value obtained by the calculation is defined as (nonwoven fabric constituent fibers consisting of short fibers + woven / knitted constituent fibers) area. In addition, when the woven or knitted fabric constituting fiber is shown as lying in the horizontal direction instead of as a fiber cross section, the area is obtained by excluding the fiber.

  In the present invention, when a polymer elastic body is imparted to the fiber laminate entangled body, a known technique such as a dip nip method can be used. However, an aqueous dispersion of a polymer elastic body is used in terms of environmental friendliness. preferable. In the case of a combination in which a fiber laminate entangled body composed of a short fiber web composed of a water-soluble polymer component and a poorly water-soluble polymer component is impregnated with an aqueous dispersion of a polymer elastic body, a water-soluble polymer is formed when nip treatment is performed. Ingredients may be squeezed out and the polymer elastic water dispersion may be contaminated. In this case, the permeability of the polymer elastic water dispersion to the water-soluble polymer component and the impregnation pressure are used together, and the polymer elastic water dispersion supply amount and A resin impregnation method capable of impregnating a predetermined amount of resin only by controlling the concentration is preferable. For example, the impregnation device is provided with edges at the inlet and outlet when the fiber laminate entanglement passes through the impregnation device, and further provided with side walls in the direction perpendicular to the processing direction, that is, in the transverse direction of the fiber laminate entanglement (width direction). A liquid reservoir chamber surrounded by the edge and the side wall is formed, and a predetermined amount of the polymer elastic body aqueous dispersion is pressurized into the fiber laminate entangled body by a pump from a slit-like discharge port in the liquid reservoir chamber. What is supplied by infiltration is preferred. The side wall is not particularly limited as long as the liquid in the liquid storage chamber can be sealed. It is preferable that the interval between the side walls provided on both sides in the crossing direction of the coalescence (supply width of the polymer elastic body aqueous dispersion) is narrower than the width of the fiber laminate entanglement, and each side wall is at least 5 cm inside from each fiber entanglement side. More preferably. The impregnation apparatus may be provided above, below, or both above and below the fiber laminate entangled body, but it is industrially advantageous that it is installed at one place downward from the viewpoint of workability and cost. .

The above impregnation method adjusts the permeability and impregnation pressure of the polymer elastomer aqueous dispersion to the fiber laminate entangled body, without using a complicated process, and without increasing the impregnation pressure. It is possible to impregnate the polymer elastic water dispersion in a uniform state in a short time. Therefore, first, with respect to the permeability of the polymer elastic water dispersion, the penetration time of the polymer elastic water dispersion into the fiber laminate entangled body is preferably 10 seconds or less, more preferably 5 seconds or less, More preferably 2 seconds or less. When the time exceeds 10 seconds, all of the polymer elastic water dispersion supplied to the fiber laminate entangled body cannot be uniformly and sufficiently impregnated inside the fiber laminate entangled body, and the polymer elastic body aqueous dispersion does not sufficiently penetrate the fiber laminate entangled body. It overflows from the united supply surface and contaminates the periphery of the solution supply unit, and further, the amount of impregnated resin inside the fiber laminate entangled unit tends to be insufficient.
In addition, the osmosis | permeation time here means the relative osmosis | permeation time of a polymeric elastic body aqueous dispersion and a fiber lamination | entanglement entanglement body. It is dropped into the entangled body, and the time from the time of dropping until the polymer elastic body aqueous dispersion completely penetrates is measured. Moreover, completely penetrating means a state in which it can be visually confirmed that the polymer elastic water dispersion is not raised on the fiber laminate entangled body. Then, the treatment may be carried out after appropriately adjusting the viscosity and concentration of the polymer elastomer aqueous dispersion so as to achieve a suitable infiltration time of the present invention. When the density of the fiber laminated entangled body is 0.40 to 0.90 g / m ³ , the viscosity of the polymer elastic body aqueous dispersion is preferably 2 to 80 cpoise, and the combination with a concentration of 30 to 60% has a penetration time of 10 This is preferable because it can be easily set to less than a second. The concentration of the elastic polymer aqueous dispersion is more preferably 35 to 50% by mass. If it is less than 30% by mass, migration tends to occur in the drying step, and if it exceeds 60% by mass, the above-mentioned permeation time tends to increase, and the amount of the impregnated resin tends to decrease.
In addition, when the combination of the viscosity and concentration of the fiber laminate entangled body and the polymer elastic water dispersion is the same combination as described above, and the penetration time exceeds 10 seconds, the polymer elastic water dispersion is used to improve the permeability. It is preferable to add a surfactant appropriately to 10 seconds or less. As the surfactant to be added, known ones such as a wetting agent, a penetrating agent and a leveling agent can be used. Among them, sulfones such as di-2-ethylhexyl sulfosuccinate sodium salt, dioctyl ester sodium sulfosuccinate and sodium dodecylbenzenesulfonate Acid salt type anionic surfactant: sulfate ester type anionic surfactants such as sodium lauryl sulfate ester, sulfated oleic acid butyl ester sodium salt, sodium dibutylnaphthalenesulfonate: polyethylene glycol mono-4-nonylphenyl ether, polyethylene Polyethylene glycol type nonionic surfactants having an HLB value of 6 to 16, such as glycol-mono-octyl ether and polyethylene glycol-mono-decyl ether: fluorinated surfactant, silicon-based surfactant It is preferred to use at least one member selected from the surface active agent.

In the above-described impregnation method, it is necessary to adjust the impregnation pressure while the permeability of the polymer elastomer aqueous dispersion to the fiber laminated entangled body satisfies the above range. In particular, in order to more uniformly impregnate the polymer laminated body with the polymer elastic body, the impregnation pressure of the polymer elastic body to be supplied is 1,000 to 100,000 Pa, depending on the density and basis weight of the fiber laminated entangled body. Is preferable, 2,000-80,000 Pa is more preferable, and 2,000-50,000 Pa is more preferable. If it is less than 1,000 Pa, the polymer elastic water dispersion to be supplied cannot sufficiently permeate the fiber laminate entangled body of the artificial leather substrate from the polymer elastic material supply surface to the opposite side. The texture is reduced. On the other hand, when it exceeds 100,000 Pa, the permeability is good, but the supplied polymer elastic body leaks from the supply surface, the surroundings are contaminated, and the workability is lowered. As the fiber laminate entangled body impregnated with the impregnation pressure of the polymer elastic body aqueous dispersion in the above range, it is necessary to use a fiber laminate entangled body having a permeability of the polymer elastic body aqueous dispersion of 10 seconds or less. More preferably, the density of the fiber laminate entangled body is 0.40 to 0.90 g / cm ³ and the basis weight is 600 to 1500 g / m ² . The impregnation pressure of the polymer elastic water dispersion here refers to the pressure in the reservoir chamber in contact with the fiber laminate entangled body, and a hydraulic pressure measuring device is installed in the reservoir chamber. Can be sought. The hydraulic pressure measuring device here is not particularly limited as long as it can measure.

The polymer elastic body constituting the polymer elastic body aqueous dispersion supplied to the fiber laminate entangled body in the present invention is not particularly limited as long as it is a polymer elastic body for impregnation used for artificial leather. Polymers and acrylic polymers are preferably used, and examples thereof include polymer dispersions obtained by dispersing the polymers in non-solvents such as water. If necessary, various organic pigments and inorganic pigments may be added. In this case, examples of the organic pigment include phthalocyanine, anthraquinone, quinacridone, dioxazine, perylene, thioindigo, Examples of the inorganic pigment include titanium oxide, carbon black, red pepper, chromium red, molybdenum red, resurge, and iron oxide.
Moreover, after impregnating the polymer elastic body aqueous solution, the polymer elastic body is heated and solidified. Examples of the solidification method include known methods. For example, a dry solidification by heat treatment or a method of heat-sensitive solidification by hot water treatment or steam treatment is preferable.
Further, in the present invention, a method of coagulating the polymer elastic body is added by a known method such as adding a thermosensitive gelling compound to the polymer elastic water dispersion so that it can be uniformly present in the entire fiber laminate entangled body. It is more preferable. A method of solidifying the polymer elastic body so that it can uniformly exist throughout the fiber laminate entangled body is more preferable.
Further, the viscosity may be in a range in which the permeability of the polymer elastic aqueous dispersion is not inhibited, and as described above, 2 to 80 cpoise is preferable, 5 to 60 cpoise is more preferable, and 10 to 50 cpoise is still more preferable.

And in order to perform uniform impregnation inside the fiber laminate entangled body, the supply amount of the polymer elastic body aqueous dispersion is preferably 60 to 100%, more preferably 70 to 99% of the fiber laminate entangled body void amount. . The amount of voids in the fiber laminate entangled body here can be determined by the following calculation method.
[Air gap amount of fiber laminate entangled body]
The void amount of the fiber laminate entangled body processed per unit time was calculated from the following calculation formula.
A = DEFG × (C / D−1) / B
A (cm ³ / min): Fiber laminate entangled void volume B (g / cm ³ ): Density C (g / cm ³ ) of polymer elastomer aqueous dispersion: Density D (g / cm ³ ) of fiber constituent resin ): Apparent density of fiber laminate entangled body (short fiber density × short fiber basis weight / fiber entangled basis weight + woven / knitted fiber density × woven / knitted fabric basis / fiber entangled basis weight)
E (cm): Fiber laminate entangled body thickness F (cm): Polymer elastic body aqueous dispersion coating width G (cm / min): Travel speed The amount of polymer elastic body water dispersion supplied is the fiber laminate entangled air gap When the amount is less than 60%, the amount of impregnation on the polymer elastic dispersion dispersion supply side of the fiber laminate entangled body is different from that on the opposite side, and the distribution of the polymer elastic dispersion within the fiber laminate entanglement is uneven. Therefore, when the artificial leather base made of the fiber laminate entangled body is finished into artificial leather, it is difficult to have a leather-like texture, and the surface feeling when finished into suede-like artificial leather tends to be inferior. On the other hand, when it exceeds 100%, the distribution of the elastic polymer dispersion in the fiber laminate entangled body is uniform, but the surface opposite to the polymer elastic dispersion liquid supply surface of the fiber laminate entangled body due to excessive supply. The polymer elastic water dispersion overflows and contaminates the impregnation equipment such as the roller in contact with it, and the polymer elastic water dispersion adheres to unnecessary portions of the fiber laminate entangled body and passes through the process. Cause problems in workability and workability.

In the impregnation method described above, the fiber laminate entangled body is preferably compressed at a gap of 40 to 99% of the fiber laminate entangled body thickness just before impregnation, and more preferably 70 to 98%. When compressed more than 40% of the fiber laminate entangled body thickness, the friction resistance between the fiber laminate entangled body and the impregnating device is large, and the fiber laminate entangled body cannot be run at a predetermined speed. Therefore, uniform and stable impregnation in the length direction of the fiber laminate entangled body becomes difficult. In addition, when the compression is weaker than 99% of the fiber laminate entanglement thickness, the liquid is easily leaked from the supply surface of the polymer elastomer aqueous dispersion to the fiber laminate entanglement, the surroundings of the impregnation apparatus are contaminated, and a predetermined amount is supplied. In addition, since all of the polymer elastic water dispersion cannot permeate, there is a tendency that the amount of impregnation of the polymer elastic body is insufficient from the estimated amount of use by calculation. Accordingly, if the compression gap is too wide or too narrow, uniform and stable impregnation is difficult. When compressing the fiber laminate entangled body after impregnation, the water-soluble polymer is eluted to contaminate the polymer elastic water dispersion, and the water-soluble polymer component constituting the ultrafine fiber-generating fiber is excessively eluted. Then, the poorly water-soluble polymer component tends to be directly exposed, the polymer elastic body in the polymer elastic body aqueous dispersion directly grips the ultrafine fibers, and the resulting artificial leather has a hard and inferior texture. Therefore, it is necessary to impregnate the fiber laminate entangled body in a compressed state immediately before impregnation. In addition, in the case where the surface layer is formed by excessively adhering to the fiber laminate entangled body supply surface in addition to the polymer polymer aqueous dispersion dispersed in the fiber laminate entangled body soaked and impregnated with a predetermined amount It is also possible to remove the surface layer by providing an edge at the exit of the fiber laminate entangled body.
Further, the above impregnation method can be processed without reducing the production rate as long as the time for the polymer elastic water dispersion to permeate can be secured. Preferably it is 2 m / min or more, More preferably, it should just be 2-10 m / min. If it is less than 2 m / min, penetration of the polymer elastic water dispersion is sufficiently possible, but the productivity is lowered due to slow processing speed, and if it exceeds 10 m / min, it is supplied depending on the penetration time. There may be a case where the entire polymer elastic body aqueous dispersion cannot be completely penetrated, and there is a concern that a predetermined amount of impregnation is difficult. Moreover, even if impregnation is possible, there is a concern that coagulation and drying will be insufficient, and if these are wiped away, treatment at 10 m / min or more is possible.
Moreover, it is preferable to provide the polymer elastic body aqueous dispersion to be impregnated so that the mass ratio of polymer elastic body: fiber entangled body = 5: 95 to 60:40. When finished as artificial leather, the polymer elastic body obtains an effect as a binder for binding fibers. When the amount is less than 5% by mass, the binder effect cannot be sufficiently satisfied. Although the effect is obtained, the physical properties such as tear strength and tensile strength are inferior, and the texture is hard and inferior.

In the present invention, as described above, when the ultrafine fiber generating fiber is used as the short fiber, the fiber laminate entangled body made of the fiber is impregnated with the polymer elastic body aqueous dispersion, and then the ultrafine fiber and the polymer elastic body are used. The extraction and removal component is removed with a treatment liquid that is a non-solvent and a solvent of the extraction and removal component, and the ultrafine fiber-generating fiber is made ultrafine. In particular, when extracting and removing, from the point of view of environmental problems or the ability to extract and remove water-extractable knitted fabrics at the same time, the extraction and removal components are removed with an aqueous solvent such as hot water or alkaline liquid to obtain ultrafine fiber-generating fibers. A method of ultra-thinning is preferable. In particular, when extracting and removing with hot water, the hot water temperature is preferably 60 to 100 ° C, more preferably 80 to 95 ° C. When the temperature is lower than 60 ° C., it takes time to remove the water-soluble polymer, so that the hot water temperature is preferably higher. However, when a temperature exceeding 100 ° C. is applied, the binding between the resin and the fiber is easy to loosen, and there is a concern that the fiber gripping property of the resin may be lowered.
If the woven or knitted fabric is present near the middle of the fiber laminate entanglement, a certain amount of voids can be created by extracting and removing the woven or knitted fabric, but the woven or knitted fabric in the fiber laminate entangled fabric is closely entangled with short fibers. Since the polymer elastic bodies are combined, there are few polymer elastic bodies, and the slightly existing polymer elastic bodies are in a state where it is difficult to form a large continuous layer. Accordingly, the internal voids are appropriately crushed and are not structurally different from those where no knitted or knitted fabric exists, and hardly affect the appearance, texture and physical properties. Also, when the woven or knitted fabric is present in the middle of the fiber laminated entangled body, the resin slightly adhered to the woven or knitted fabric does not form a large continuous layer as described above. The resin adhering to the fibers remains on the fiber laminated entangled body, and holds the short fibers firmly. Therefore, even when the woven or knitted fabric is present in the fiber laminate entangled body or on the surface layer, the surface after the water-extraction removal of the woven or knitted fabric is not roughened, so that additional processing such as buffing is unnecessary.

  In the present invention, the thickness is adjusted to a desired thickness by pressure heating treatment or division treatment as necessary. Further, at least one surface of the short fiber may be subjected to a raising process such as a buffing process to form an ultrafine fiber raised surface mainly composed of an ultrafine fiber to form a suede-like artificial leather. When the short fiber is an ultrafine fiber generating fiber, a raising process such as a buffing process may be performed before or after the ultrafine fiber generating fiber is ultrafine. In that case, finishing treatment such as stagnation softening and reverse seal brushing can be performed as necessary. Since the suede-like artificial leather obtained in the present invention has less spotted spots, the amount of fibers in the width direction of the product is uniform, and as a result, color spots at both ends and the center are suppressed. A feeling of fullness can be obtained, and at the same time, a good quality without colored spots can be obtained.

In the present invention, the density of the obtained artificial leather is preferably 0.50 to 0.85 g / cm ³ . When the density is less than 0.50 g / cm ³ , physical properties such as tear strength are inferior. When the density is greater than 0.85 g / cm ³ , the flexibility is inferior and the texture is deteriorated. Preferably, it is the range of 0.53-0.80 g / cm < ³ >. The density of conventional artificial leather is in the range of 0.3 to 0.45 g / cm ³ , and it can be said that the artificial leather of the present invention is very high, and this high density is notified to the artificial leather of the present invention to natural leather. It provides a smooth texture, fullness, drape, and excellent mechanical properties.

  The artificial leather of the present invention can be provided with a resin layer as necessary to obtain an artificial leather with a tone with silver or with a semi-silver. Moreover, the nonwoven fabric surface layer part can be melted to form a resin layer by heating the surface and pressing it on a smooth surface. As the resin applied to the surface, an elastic polymer typified by polyurethane or acrylic is preferably used. Further, the coloring treatment may be performed using a very small amount of dye or a small amount of pigment. Further, if necessary, the artificial leather of the present invention is used as an upper layer, and a knitted fabric or a knitted fabric is bonded together as a lower layer, or the raised nail artificial leather of the present invention is used as an upper layer, and the napped-toned artificial leather A layer made of a different kind of fiber from the fibers constituting the layer may be bonded to form a lower layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples. Evaluations such as performance measurement described in the following examples and comparative examples were performed by the following methods.

Polyvinyl terephthalate containing 10 mol% of isophthalic acid (melting point 234 ° C) to which 0.5% by mass of carbon black is added is an island component, contains 10 mol% of ethylene units, has a saponification degree of 98.4 mol%, and a melting point of 210 ° C. A single yarn fineness of 5.5 dtex was obtained by subjecting an alcohol copolymer (Exebar, manufactured by Kuraray Co., Ltd.) to sea components and a composite spinning of 64 islands of islands with a mass ratio of sea / island = 30/70, followed by stretching. A fiber with a density of 1.27 g / cm ³ was obtained. The fiber was crimped, cut to 51 mm, and carded to prepare a short fiber web having a basis weight of 200 g / m ² .

Next, a polyvinyl alcohol copolymer containing 10 mol% of ethylene units, having a saponification degree of 98.4 mol% and a melting point of 210 ° C. (Exeval manufactured by Kuraray Co., Ltd.) is spun and stretched under normal conditions by a roller plate method. Thus, a fiber having a single yarn fineness of 3.1 dtex and a density of 1.25 g / cm ³ was obtained. A woven fabric having a weight per unit area of 80 g / m ² was prepared from this fiber.

The two webs were stacked in advance, and a scrim was stacked thereunder, and then needle punching was performed under the condition of 2500 punch / cm ² . Next, the film was shrunk by 30% by a heat shrink process at 205 ° C. (area retention rate 70%), and further heat-pressed at 175 ° C. to have a basis weight of 630 g / m ² , an apparent density of 0.75 g / cm ³ and a thickness of 0.84 mm. A fiber laminate entangled body was obtained. Moreover, the surface exposure degree of the woven or knitted fiber in this fiber laminated entangled body was 2.0%.

Next, a gray water-dispersed pigment (Ryudye W gray, manufactured by Dainippon Ink & Chemicals, Inc.) and an ether-based polyurethane water-dispersed emulsion (Evaphanol AP-12, manufactured by Nikka Chemical Co., Ltd.) have a solid content of pigment / emulsion = 1.8 / 100. The mixture was mixed in a mass ratio to obtain a polymer elastic water dispersion having a concentration of 40% by mass, a viscosity of 20 cpoise, and a density of 1.02 g / cm ³ .

Next, a lip coater equipment (a lip direct system manufactured by Hirano Techseed Co., Ltd.) was used as the impregnation equipment, B (density of the polymer elastic body aqueous dispersion): 1.02 g / cm ³ , C (density of the fiber constituent resin): 1. 26 g / cm ³ , D (apparent density of fiber entangled body) 0.75 g / cm ³ , E (thickness of fiber entangled body): 0.84 mm, F (polymer elastic body aqueous dispersion coating width): 170 cm, G (Running speed): Fiber entangled body obtained by ultrafine fiber formation of a polymer elastic body aqueous dispersion in an amount corresponding to 80% of A (fiber entangled void amount) 1733 cm ³ / min calculated from 2.5 m / min / Polymer elastic body = impregnated so as to have a mass ratio of 74/26. Immediately after that, the mixture was heated and solidified and dried in a hot air dryer at 160 ° C. for 3 minutes 30 seconds. Thereafter, unimpregnated portions of 5 cm on both sides were cut, and a polyvinyl alcohol copolymer component was extracted with hot water at 90 ° C. to obtain a base for artificial leather. The obtained substrate for artificial leather had a good appearance with no wrinkles or elongation, and was a substrate for artificial leather having a uniform leather-like texture and excellent physical properties. The surface of the obtained artificial leather essential substrate was subjected to raising treatment by buffing to obtain a suede-like artificial leather.

Next, Sumikaron UL dye (manufactured by Sumitomo Chemical Co., Ltd.) Yellow 3RF 0.24 owf%, Red GF 0.34 owf%, Blue GF 0.70 owf%, Antifade MC-500 (manufactured by Meisei Chemical Co., Ltd.), High pressure dyeing was performed at 130 ° C. using 2 ow% and Disper TL (manufactured by Meisei Chemical Co., Ltd.) 1 g / L. In the production of artificial leather, the change in form from the heat shrinkage of the fiber laminate entangled body to after the dyeing treatment was as small as length × width = 102% × 98%. The obtained suede-like artificial leather had a sense of fulfillment, and the basis weight difference between the center and both ends was as small as 20 g / m ² . In addition, there was no color unevenness at both ends and the center, and the color development of gray was excellent, and the texture such as suede feeling and drape was excellent.

(Weaving and knitting composition change)
The same operation as in Example 1 was performed except that a fabric with a basis weight of 100 g / m ² was used. As a result, the obtained suede-like artificial leather had a sense of fulfillment, and the basis weight difference between the central portion and both ends of the suede-like artificial leather was as small as 15 g / m ² . In addition, there was no color unevenness at both ends and the center, and the color development of gray was excellent, and the texture such as suede feeling and drape was excellent.

(Short fiber component sea component change)
A fiber laminate entangled body was produced in the same manner as in Example 1 except that the short fiber sea component was polyethylene. Next, after performing a hot water shrinkage treatment at 90 ° C., the same operation as in Example 1 was performed except that a polyurethane DMF solution was impregnated as a polymer elastic body by a dip-nip method, and then polyethylene was extracted with toluene. It was. As a result, the obtained suede-like artificial leather had a sense of fulfillment, and the difference in basis weight between the center and both ends of the suede-like artificial leather was as small as 19 g / m ² . In addition, there was no color unevenness at both ends and the center, and the color development of gray was excellent, and the texture such as suede feeling and drape was excellent.

(Shrinkage rate change)
The same operation as in Example 1 was performed except that the heat shrink treatment was performed at 190 ° C. and the area was shrunk by 25% (area retention rate: 70%). The obtained suede-like artificial leather had a feeling of solidity, had no color spots at both ends and the center, and was excellent in gray color development, and was excellent in texture such as suede and drape.

(Fiber laminate density change)
A heat press was performed at 185 ° C. after the heat shrink treatment, and the same operation as in Example 1 was performed except that the density of the fiber laminate entangled body was 0.87 g / cm ³ . As a result, there was no wrinkle or crease in the suede-like artificial leather manufacturing process, and the shape change from after the heat shrinkage of the fiber laminate entangled body to after the dyeing treatment was as small as vertical × horizontal = 101% × 99%. The obtained suede-like artificial leather had no gray spots at both ends and the central part, was excellent in gray color development, and was excellent in texture such as suede feeling and drape.

Comparative example 1 (weaving / knitting change)
Using fabric having a basis weight of 80 g / m ² made of polyethylene, except that the method for removing fabric was carried out with hot toluene extraction method were carried out in the same manner as in Example 1. As a result, in the suede-like artificial leather manufacturing process, there was no wrinkle or crease, and the form stability was excellent. However, when this woven or knitted fabric is removed, extraction with toluene requires repeated dip / nip treatment for polyethylene extraction, which not only takes a lot of processing time, but also the substrate for artificial leather is greatly compressed by dip / nip treatment. The obtained suede-like artificial leather had a difference in basis weight of 15 g / m ² between the central portion and both ends, but the difference was small, but the feeling of swelling was lacking and the texture was inferior.

Comparative example 2 (textile removal method change)
The same operation as in Example 1 was performed except that the fabric of Example 1 was removed by buffing treatment. As a result, in the suede-like artificial leather manufacturing process, there was no wrinkle or breakage, and the change in shape from the heat shrinkage of the fiber laminate entangled body to the dyeing was as small as vertical x horizontal = 102% x 98%. Further, the difference in basis weight between the center portion and both end portions of the obtained suede-like artificial leather was as small as 20 g / m ² . However, the short fiber portion was partly ground and removed by the buffing treatment when removing the fabric, and the resulting artificial leather was thin and inferior in texture.

Comparative Example 3 (no heat shrink treatment)
The same operation as in Example 1 was performed except that the heat shrink treatment was omitted. As a result, there was no wrinkle or crease in the suede-like artificial leather production process, and there was little change in form from heat shrinkage to dyeing of the fiber laminate entangled body. Moreover, the obtained suede-like artificial leather had a small difference in basis weight of 20 g / m ² between the center and both ends of the fiber laminate entangled body. However, the fluff density on the surface of the artificial leather was low and the texture was inferior.

Claims (5)

A method for producing artificial leather, comprising sequentially performing the following steps (1) to (4) when producing an artificial leather in which a polymer elastic body is provided inside a fiber entangled body.
(1) The process of manufacturing a fiber lamination entangled body by carrying out an entanglement integration process, after laminating | knitting the woven / knitted fabric which consists of a fiber which can be substantially extracted by water extraction with a short fiber web,
(2) a step of thermally shrinking the fiber laminate entangled body,
(3) A step of providing a polymer elastic body inside the fiber laminate entangled body,
(4) a step of extracting and removing the woven or knitted fabric with water, The method for producing artificial leather according to claim 1, wherein the short fiber web is an ultrafine fiber-generating fiber comprising a water-soluble polymer component and a poorly water-soluble polymer component. Modified polyvinyl alcohol in which the fiber which can be removed by water extraction and constituting the woven or knitted fabric contains 1 to 20 mol% of α-olefin units and / or vinyl ether units having 4 or less carbon atoms, and has a saponification degree of 90 to 99.99 mol% The manufacturing method of the artificial leather of Claim 1 or 2 consisting of. The artificial leather obtained by the manufacturing method of any one of Claims 1-3. A suede-like artificial leather obtained by raising the artificial leather according to claim 4.