WO2021085427A1

WO2021085427A1 - Artificial leather and production method therefor

Info

Publication number: WO2021085427A1
Application number: PCT/JP2020/040288
Authority: WO
Inventors: 大介弘中; 義幸田所; 慶一郎阪田; 正也川嵜; 挙山本; 久貴池端
Original assignee: 旭化成株式会社
Priority date: 2019-10-30
Filing date: 2020-10-27
Publication date: 2021-05-06
Also published as: US20220372698A1; KR20220062099A; JP7282908B2; EP4053330A4; EP4053330A1; CN114630935A; JPWO2021085427A1

Abstract

Provided is an artificial leather that has texture (stiffness), a luxuriant feel (dispersibility of fiber bundles), and a slick feel (resin clusters of appropriate size) and can be used suitably as a seat cover material or interior design material for interiors, cars, airplanes, railway cars, etc. and garment accessory products. This artificial leather comprises a fiber sheet and a polyurethane resin and is characterized in that: the fiber sheet comprises at least a fiber layer (A) that forms a first outer surface of the artificial leather; the k-nearest neighbor distance proportion (k=9, radius r=20µm) between cross-sections of single fibers configuring the fiber layer (A) in a thickness direction cross-section of the artificial leather is 10-80%; the cross-sectional polyurethane resin area ratio in a thickness direction cross-section of the fiber layer (A) is 10-30%; and the standard deviation of the cross-sectional polyurethane resin area ratio in a thickness direction cross-section of the fiber layer (A) is 25% or less.

Description

Artificial leather and its manufacturing method

The present invention relates to an artificial leather having both a texture (rigid and soft value), a dense feeling (dispersibility of fiber bundles), and a moist feeling (a resin lump of an appropriate size) and a method for producing the same.

Artificial leather composed mainly of fiber sheet (fiber base material) such as non-woven fabric and polyurethane (hereinafter also referred to as PU) resin is difficult to realize with natural leather such as easy care, functionality, and homogeneity. It has excellent characteristics, such as clothing, shoes, bags, and leather and interior materials for seats for interiors, automobiles, aircraft, railroad vehicles, etc., and clothing materials such as ribbons and emblem base materials. It is preferably used in.

Conventionally, as a method for producing such artificial leather, a fiber sheet is impregnated with an organic solvent solution of PU resin and then immersed in a non-solvent (for example, water or an organic solvent) of PU resin to immerse the PU resin. A method of wet coagulation is generally adopted. For example, in Patent Document 1 below, an organic solvent-based PU resin using N, N-dimethylformamide is used as the organic solvent that is the solvent for the PU resin. However, since organic solvents are generally highly harmful to the human body and the environment, there is a strong demand for a method that does not use organic solvents in the production of artificial leather.

In the following Patent Document 2, a method of using an aqueous dispersion type PU resin dispersion liquid in which the PU resin is dispersed in water is studied instead of the conventional organic solvent-based PU resin, but the aqueous dispersion type PU resin dispersion The sheet-like material obtained by impregnating the liquid with a fiber sheet and solidifying the PU resin has a problem that the texture tends to be hard. One of the main reasons is the difference between the two coagulation methods. That is, the coagulation method of the organic solvent-based PU resin dispersion liquid is a "wet coagulation method" in which PU molecules are precipitated and solidified by substituting the organic solvent in which PU molecules are dissolved with water, and the PU membrane is used. When viewed, it forms a low-density porous film. Therefore, even when the PU resin is impregnated into the fiber sheet and solidified, the bonding points between the fiber and the PU resin are present in dots, and the PU resin tends to have a porous structure, so that the PU resin becomes a soft sheet-like material. On the other hand, the water-dispersed PU resin is a "dry heat coagulation method" in which the hydration state of PU molecules dispersed in water is disintegrated mainly by heating and the PU molecules are solidified by aggregating each other. The obtained PU film structure is a dense non-porous film. Therefore, the adhesion between the fiber and the PU resin becomes dense, and the entangled portion of the fiber is strongly gripped, so that the texture becomes hard. In order to improve the texture by applying this water-dispersible PU resin, that is, to suppress the gripping of the fiber entanglement points by the PU resin, a technique for making the structure of the PU resin in the sheet-like material a porous structure has been proposed. A sheet-like material containing a water-dispersible PU resin, a foaming agent, an anionic surfactant, and / or a PU resin dispersion liquid containing an amphoteric surfactant is applied to the fiber sheet. The porous structure of the PU resin inside the sheet can be expressed regardless of the type of foaming agent and PU, and the raised length is as uniform as that of artificial leather to which the organic solvent-based PU resin is applied. It is disclosed that it is possible to produce a sheet-like material having a graceful surface quality excellent in a feeling of fineness and a good texture that is flexible and has an excellent feeling of repulsion.
However, in the sheet-like material obtained by the method described in Patent Document 2, the gap between the ultrafine fiber bundle and the PU resin is large (the PU resin has a porous structure), and the PU resin is strong in the ultrafine fiber bundle. As a result of the suppression of adhesion to the PU resin, some softening of the texture is observed, but the cross-sectional PU resin area ratio is still relatively high, the dispersibility of the PU resin is not sufficient, and the dispersibility of the single fiber is Has not been considered.

Further, Patent Document 3 below describes a sheet-like material having a uniform feeling comparable to that of artificial leather to which an organic solvent-based PU resin is applied, and having an elegant surface quality and a good texture, a manufacturing method thereof, and further. By applying a water-dispersible PU resin, a porous structure of the PU resin is achieved, and a sheet-like material with crease recovery and flexibility that closely resembles artificial leather to which an organic solvent-based PU resin is applied and its manufacturing method. In order to provide, as a solution thereof, a sheet form in which a polymer elastic body having a hydrophilic group (for example, an aqueous dispersion type PU resin) is added as a binder to a fiber sheet composed of ultrafine fibers and / or ultrafine fiber bundles. In the cross section of the material cut in the thickness direction of the sheet-like material, the occupancy ratio of the portion of the ^{polymer elastic body observed in the cut surface that has a cross-sectional area of 50 μm 2 or more independently is} Those having an artificial leather cross section area of 0.1% or more and 5.0% or less in the observation field are disclosed, and as a manufacturing method thereof, a fiber sheet made of ultrafine fibers has a polymer elasticity having a hydrophilic group. In a method for producing a sheet-like material in which a body is applied as a binder, a dispersion liquid containing the polymer elastic body and a thickener is applied to a fiber sheet, and the polymer is added to hot water at a temperature of 50 to 100 ° C. It has been proposed to solidify the elastic body. In the same document, as the thickener, guar gum or the like having high thixotropy at a low concentration is used, and if the dispersion is thixotropy, the viscosity is lowered by applying force by stirring or the like, and the dispersion is said. Can be uniformly impregnated in the fiber sheet, and the viscosity is restored by allowing the fiber sheet to stand after further applying force, so that the dispersion liquid impregnated in the fiber sheet falls off from the fiber sheet. It is stated that it will be difficult.
However, in the sheet-like material obtained by the method described in Patent Document 3, the size of the water-dispersed PU resin is controlled (the PU resin mass is miniaturized), and as a result, the resin falls off, the texture, and the appearance. Although a slight improvement in quality is observed, the cross-sectional PU resin area ratio is high, the dispersibility of the PU resin is not sufficient, and the dispersibility of the single fiber has not been studied.

The following Patent Document 4 describes a three-dimensional entangled non-woven fabric and a polymer for the purpose of providing a base material for artificial leather having excellent mechanical properties, flexibility, texture, and light weight. A base material for artificial leather made of an elastic body, and the following requirement (1): The polymer elastic body is discontinuously present on the surface of the fiber forming the three-dimensional entangled non-woven fabric; Requirement (2): Artificial leather The average area of the inscribed circle of the gap excluding the area of the inscribed circle of the gap of less than ^{350 μm 2 in the} cross section parallel to the thickness direction of the base material ^{is 1250 μm 2} or less; and Requirement (3): Base for artificial leather Check clearance inscribed circle the number of empty gaps inscribed circle area 350 ~ 3000 .mu.m ² in a cross section parallel to the thickness direction of the wood is, the total air gap inscribed circle number to is 85%; meet for artificial leather base The material has been proposed. Such a base material for artificial leather is subjected to a step of impregnating a three-dimensional entangled non-woven fabric with an aqueous dispersion type PU resin dispersion liquid in which polyvinyl alcohol (hereinafter, also referred to as PVA) resin is added and coagulating it to form a polymer elastic body. It is obtained by passing through. In Patent Document 4, the polymer elastic body has a certain release structure from the fiber and is discontinuously present on the fiber surface, and the PU resin is uniformly dispersed inside, so that the interfiber voids are uniformly distributed. It is said that an artificial leather base material used for sports shoes and the like, which has excellent mechanical properties, is flexible, lightweight, and has an excellent texture can be obtained.
However, in the base material for artificial leather obtained by the method described in Patent Document 4, the dispersibility of the water-dispersible PU resin is improved, and although it is flexible and lightweight, the dispersibility of the single fiber is not good. , It lacks a sense of precision. Further, the base material for artificial leather described in Patent Document 4 is mainly used for "smooth" artificial leather having a grain-like appearance.

The following Patent Document 5 describes a sheet-like material, particularly a leather-like sheet-like material having excellent long-term good surface touch, color development and appearance quality, and an average single fiber diameter thereof for the purpose of providing a method for producing the same. A sheet-like material containing a polymer elastic body inside a fiber sheet containing 0.3 to 7 μm ultrafine fibers and having fluff on the surface, 0.2 μm in the thickness direction from the surface of the sheet-like material. For the fluffy fibers existing within, the average value of the shortest interfiber distance between one of the 100 randomly selected fluffy fibers and the closest fluffy fiber was 10 to 30 μm, and the fibers were randomly selected. A sheet-like material has been proposed in which the standard deviation of the interfiber distance between the surrounding 20 fluffy fibers selected in order of proximity to one of the 100 extracted fibers is 10 or less. There is. The sheet-like material is obtained in the following step 1: a step of removing the sea component of the fiber sheet containing sea-island type fibers to develop ultrafine fibers; step 2: a step of alkali-reducing the ultrafine fibers of the fiber sheet containing the ultrafine fibers. Step 3: A step of imparting a polymer elastic body to the obtained fiber sheet after the above steps 1 and 2; Step 4: After the above step 3, the obtained sheet-like material is subjected to the thickness direction. It is said that it is obtained by a step of raising at least one surface of a sheet-like material obtained by halving and halving. In Patent Document 5, it is preferable to perform a treatment for uniformly dispersing the ultrafine fibers after the alkali weight reduction treatment of the ultrafine fibers, and for the treatment for uniformly dispersing the ultrafine fibers, showering with water is applied to the fiber sheet after the alkali weight reduction. There are a method of immersing the fiber sheet in water and applying a water stream such as a vibro washer to disperse the fiber sheet, and a method of applying a water stream with a water jet punch to disperse the fibers. As a result, the dispersal of the ultrafine fibers becomes uniform, and by using fibers with good color development with an average single fiber diameter of 0.3 to 7 μm, it is not a temporary improvement of the surface touch by applying a drug, but a fluffing especially in the long term. It is described that a sheet-like material having a good dispersed state, a good surface touch (no rough feel), uniform fluffing, an elegant appearance quality, and excellent color development can be obtained.
However, in the process of uniformly dispersing the ultrafine fibers as described in Patent Document 5, the process of applying a water stream such as a vibro washer to disperse the fibers does not have sufficient dispersibility of the fibers, and the PU Since the dispersibility of the resin is also inferior, neither the dense feeling nor the moist feeling is sufficient, and the texture (rigid / soft value) is unknown.

As described above, in the prior art, in artificial leather obtained by impregnating a fiber sheet using sea-island type fibers with PU resin, the texture (rigidity / softness value) is improved by enhancing the dispersibility of the fibers and the dispersibility of the PU resin. ), Denseness (dispersity of fiber bundles), and moistness (appropriate size of PU resin mass) have been various attempts to provide artificial leather, but the texture (rigid and soft value) and denseness. There is a trade-off between the feeling and the moist feeling (appropriate size of the PU resin lump), and the texture (rigid and soft value), the dense feeling (dispersity of the fiber bundle), and the moist feeling (the appropriate size of the PU resin lump). ) Satisfying the level of artificial leather and its manufacturing method have not yet been achieved.

Japanese Patent No. 4089324 Japanese Unexamined Patent Publication No. 2014-25165 International Publication No. 2015/129602 JP-A-2017-8478 JP-A-2015-161040

In view of the above-mentioned problems of the prior art, the problems to be solved by the present invention are low harmfulness to the human body and the environment, texture (rigidity and softness value), tightness (dispersity of fiber bundles), and It is an object of the present invention to provide artificial leather and a method for producing the same, which have a satisfactory level of moistness (appropriate size of PU resin lump).

As a result of diligent research and experiments to solve the above problems, the present inventors unexpectedly found that artificial leather having the following characteristics could solve the problems, and completed the present invention. It is an invention.
That is, the present invention is as follows.
[1] An artificial leather containing a fiber sheet and a polyurethane resin, wherein the fiber sheet contains at least a fiber layer (A) constituting the first outer surface of the artificial leather, and the thickness of the artificial leather. The k proximity distance ratio value (k = 9, radius r = 20 μm) between the single fiber cross sections constituting the fiber layer (A) in the directional cross section is 10% or more and 80% or less, and the fiber layer (A). ), The cross-sectional polyurethane resin area ratio in the thickness direction cross section is 10% or more and 30% or less, and the standard deviation of the cross-sectional polyurethane resin area ratio in the thickness direction cross section of the fiber layer (A) is 25% or less. The artificial leather to be characterized.
[2] In a three-dimensional image of the fiber layer (A) by X-ray CT, the space size is the diameter of the largest sphere that enters the space excluding the fibers constituting the fiber layer (A) and the polyurethane resin. The artificial leather according to the above [1], wherein the average value (average space size) in the thickness direction of the fiber layer (A) is 5 μm or more and 35 μm or less.
[3] The fiber sheet has two or more layers composed of a fiber layer (A) constituting the first outer surface and a scrim and / or a fiber layer (B) in contact with the fiber layer (A). The artificial leather according to the above [1] or [2], which has a structure.
[4] The artificial leather according to any one of [1] to [3], wherein the average diameter of the single fibers constituting the fiber layer (A) is 1.0 μm or more and 8.0 μm or less.
[5] The artificial leather according to any one of [1] to [4] above, wherein the polyurethane resin is a water-dispersible polyurethane resin.
[6] The artificial leather according to any one of [1] to [5], wherein the adhesion ratio of the polyurethane resin to the fiber sheet is 15% by mass or more and 50% by mass or less.
[7] The artificial leather according to any one of [1] to [6] above, wherein the hardness and softness value is 28 cm or less.
[8] The artificial leather according to any one of [1] to [7], wherein the fiber sheet is made of polyester fiber.
[9] The artificial leather according to any one of [1] to [8] above, which has a feeling of fineness of 4.0 grade or higher.
[10] The following steps:
A step of forming a fiber web from Kaijima short fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the island component single fibers are exposed; and water flow dispersion on the obtained fiber sheet. The process of applying treatment to obtain a fiber sheet in which single fibers are dispersed;
The method for producing artificial leather according to any one of the above [1] to [9], which comprises.
[11] The following steps:
The fiber sheet in which the single fibers are dispersed is impregnated with a water-dispersed polyurethane resin dispersion liquid containing hot water-soluble resin fine particles, and then the polyurethane resin is fixed by heating to form a sheet filled with the polyurethane resin. A step of obtaining a product; and a step of removing the hot water-soluble resin fine particles from the obtained sheet-like material using hot water;
The production method according to the above [10], further comprising.
[12] The production method according to the above [10] or [11], wherein the hot water-soluble resin fine particles are polyvinyl alcohol resins.
[13] The water flow dispersion treatment is carried out using a plurality of nozzles having a nozzle hole spacing of 1.0 mm or less and a nozzle hole diameter of 0.05 mm or more and 0.30 mm or less. The production method according to any one of [12].
[14] The production method according to any one of [10] to [13], wherein the water flow dispersion treatment is carried out using a plurality of nozzles that discharge a water flow having a disturbance of 10% or more.
[15] The production method according to any one of [11] to [14], wherein the solid content concentration of the aqueous dispersion type polyurethane resin dispersion liquid is 10% by weight or more and 35% by weight or less.
[16] The production according to any one of [11] to [15] above, wherein the content of the hot water-soluble resin fine particles in the water-dispersible polyurethane resin dispersion is 1% by weight or more and 20% by weight or less. Method.

The artificial leather according to the present invention is excellent in texture (rigid and soft value), tightness (dispersity of fiber bundles), and moist feeling (appropriate size of polyurethane resin mass), and therefore is used for interiors, automobiles, and aircraft. It can be suitably used for clothing products such as skin materials or interior materials for seats for railway vehicles.

FIG. 1 is a conceptual diagram showing a configuration example of artificial leather of reference numeral 1. Since the scrim of reference numeral 11 and the fiber layer (B) of reference numeral 13 are arbitrary, the artificial leather of the present embodiment is referred to as the fiber layer (A) in the case of a single layer of the fiber layer (A) of reference numeral 12. In the case of two layers of scrim or fiber layer (B), there are cases of three layers of fiber layer (A), scrim and fiber layer (B). FIG. 2 is a conceptual diagram illustrating how to obtain the average diameter of the fibers constituting the fiber layer (A). FIG. 3 shows the ratio value (%) of the distance near the single fiber cross section k in the cross section in the thickness direction from the fiber layer (A), the cross-sectional PU resin area ratio, the average diameter of the single fibers, and the surface PU resin area on the first outer surface. It is a conceptual diagram explaining each sampling place of rate and space size. FIG. 4 is an image showing a state in which each single fiber cross section in a predetermined image region is marked by a person in order to obtain a distance ratio value (%) in the vicinity of the single fiber cross section k in the cross section in the thickness direction. FIG. 5 is a conceptual diagram for explaining how to obtain the distance ratio value (%) in the vicinity of the single fiber cross section k in the cross section in the thickness direction. FIG. 6 is a conceptual diagram for explaining how to obtain the cross-sectional or surface PU resin area ratio and its standard deviation. FIG. 7 is a graph comparing Examples and Comparative Examples with respect to the cross-sectional PU resin area ratio (%) and its standard deviation. FIG. 8 is a conceptual diagram showing the nozzle hole spacing when the nozzle holes of the nozzles used for the water flow dispersion treatment are in one row or two or more rows.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments. Unless otherwise specified, the various values of the present disclosure are values obtained by a method described in the [Examples] section of the present disclosure or a method understood by those skilled in the art to be equivalent thereto.

<Artificial leather>
One embodiment of the present invention is an artificial leather containing a fiber sheet and a PU resin, wherein the fiber sheet contains at least a fiber layer (A) constituting the first outer surface of the artificial leather, and The k-near distance ratio value (k = 9, radius r = 20 μm) between the single fiber cross sections constituting the fiber layer (A) in the thickness direction cross section of the artificial leather is 10% or more and 80% or less, and The cross-sectional polyurethane resin area ratio in the thickness direction of the fiber layer (A) is 10% or more and 30% or less, and the standard deviation of the cross-sectional polyurethane resin area ratio in the thickness direction of the fiber layer (A) is 25. % Or less of the artificial leather.

In the present specification, "artificial leather" is defined as "a special non-woven fabric (mainly a fiber layer having a random three-dimensional three-dimensional structure as a base material, PU resin or a similar flexible material" according to the Household Goods Quality Labeling Law. Those using (impregnated with molecular elastic material) ". In addition, according to the definition of JIS-6601, artificial leather is classified into "smooth" which has a grain-like appearance of leather and "nap" which has the appearance of leather suede, velor, etc., depending on its appearance. The artificial leather of the embodiment relates to what is classified as "nap" (ie, suede-like artificial leather having a brushed appearance). The suede-like appearance can be formed by buffing (raising) the outer surface of the fiber layer (A) (that is, the surface to be the first outer surface of the artificial leather) with sandpaper or the like. In the present specification, the first outer surface of the artificial leather is a surface exposed to the outside when the artificial leather is used (for example, in the case of a chair application, the surface on the side that comes into contact with the human body) ( (See FIGS. 1 and 3). In one aspect, in the case of suede-like artificial leather, the first outer surface is brushed or raised by buffing or the like.
In the present specification, unless otherwise specified, the term "fiber web" refers to the state before entanglement of short fibers, and the term "fiber sheet" refers to the state after entanglement and before filling with PU resin. The "state" means the state after the PU resin is filled and before the dyeing finish, and the term "artificial leather" means the state of the product after the dyeing finish. Further, the term "nonwoven fabric" includes "fiber web", "fiber sheet", "sheet-like material", and "artificial leather", and the term "fiber base material" is used in the term "nonwoven fabric". In addition, woven and knitted fabrics are also included.

[K-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) between the cross sections of the single fibers constituting the fiber layer (A)]
One feature of this embodiment is that the k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) between the single fiber cross sections constituting the fiber layer (A) in the thickness direction cross section of the artificial leather is 10% or more. It is 80% or less. The k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) indicates the degree of density of single fibers.
The measurement method will be described later, but the k-nearest neighbor method takes up k single fiber cross sections that are close to any one single fiber cross section, and takes up the Euclidean distance (that is, the square root of the sum of squares of the distances in the X and Y directions (=). In the shortest distance)), the radius closest to the k-th is the determination boundary. In this embodiment, an SEM image is taken and k = within a radius of 20 μm from the substantially center of any one single fiber cross section. Determine if there is a single fiber cross section close to the ninth. For all the single fiber cross sections in one SEM image, the presence or absence of the single fiber cross section is determined, and the single fiber cross section k = 9 neighborhood distance ratio value (%) is calculated by the following formula:
Single fiber cross section (k = 9) Near distance ratio value (%) = {(Number of single fiber cross sections in which k = 9th closest single fiber cross section exists within a radius of 20 μm from the approximate center of the single fiber cross section. ) / (Total number of single fiber cross sections in one SEM image)} x 100.
If the k-neighborhood distance ratio value (k = 9, radius r = 20 μm) between the single fiber cross sections constituting the fiber layer (A) in the thickness direction cross section of the artificial leather is 10% or more, the single fibers are appropriately dispersed. As a result, the PU resin mass of the fiber layer (A) also exists in an appropriately dispersed state, and when the artificial leather is touched with a fingertip, the PU resin mass of the appropriately dispersed fiber layer (A) is touched. , The moist feeling (the size of the PU resin lump) is satisfactory. On the other hand, when the k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) is 80% or less, the single fibers are appropriately agglomerated, so that the feeling of denseness (dispersity of the fiber bundle) is high and the texture is smooth. It becomes. The k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) is preferably 20% or more and 70% or less, and more preferably 30% or more and 60% or less.

As will be described later, it is obtained after the step of forming a fiber web with Kaijima short fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the single fibers of the island component are exposed. By subjecting the fiber sheet to a water flow dispersion treatment to obtain a fiber sheet in which single fibers are dispersed, the k proximity distance ratio value (k = 9, radius r = 20 μm) is controlled within the range of 80% or less. be able to. The water flow dispersion treatment is preferably carried out by injecting high-pressure water using a plurality of nozzles having a nozzle hole spacing of 1.00 mm or less. As shown in FIG. 8, the nozzle hole spacing is the distance in the nozzle width direction between the nozzle holes and the nozzle holes most adjacent to the nozzle holes in the nozzle width direction (even when there are two or more rows of nozzle holes, 1). Same as for columns). By setting the nozzle hole spacing to 1.00 mm or less, it is possible to discharge a water stream with a fine spacing on the fiber sheet, and by dispersing the single fibers in the state of a single fiber bundle, the feeling of fineness and moistness is improved. Easy to make. In addition, the water flow locus due to the water flow dispersion treatment on the fiber sheet surface is inconspicuous. The nozzle hole spacing is preferably 0.60 mm or less, more preferably 0.30 mm or less.

Further, the number of rows of nozzle holes opened in the width direction of the water flow dispersion treatment equipment may be one row or multiple rows of two or more rows. When performing the water flow dispersion treatment, it is common to remove the water charged into the fiber sheet by the water flow dispersion treatment from the viewpoint of maintaining the uniformity and morphological stability of the fiber sheet, and the suction method is performed from the opposite surface of the water flow dispersion treatment surface. Dehydrate by such as. In that case, for example, when the nozzle hole spacing is narrowed with one nozzle hole row, the dehydration capacity may be insufficient with respect to the amount of water input, and as a result, the uniformity and morphological stability of the fiber sheet may deteriorate. On the other hand, it is preferable to reduce the amount of water input per row of nozzle holes by increasing the number of rows and widening the interval between nozzle holes per row of nozzle holes because it is easy to balance the amount of water input and the dehydration capacity. It is an aspect. For example, when dehydration failure occurs in a single-row nozzle having a nozzle hole spacing of 0.30 mm, a two-row nozzle having a nozzle hole spacing of 0.60 mm is used, and the second row has a phase difference of 0. If a nozzle hole row of 30 mm and a nozzle spacing of 0.60 mm is arranged, the water flow locus (nozzle hole spacing) becomes 0.30 mm, and the effect of improving dehydration failure can be obtained. Further, it is preferable to widen the nozzle hole spacing and make the number of rows large because the nozzle work becomes easy. Equal intervals are preferable because the nozzle hole spacing (water flow locus) makes it easy to uniformly disperse the single fibers, the water flow locus is inconspicuous, and the feeling of fineness and moistness is easily improved.
When the number of nozzle hole rows is large, the distance between the nozzle hole rows is preferably a distance corresponding to, for example, the nozzle hole spacing in one nozzle row from the viewpoint of dehydration.

The hole diameter of the high-pressure water injection nozzle hole in the water flow dispersion treatment is 0 because high single fiber dispersion can be easily obtained, the water flow trajectory is inconspicuous, and the amount of water input is not excessive and the balance with the dehydration capacity is easy to be achieved. It is preferably 0.05 mm or more and 0.30 mm or less, more preferably 0.05 mm or more and 0.20 mm or less, and further preferably 0.08 mm or more and 0.13 mm or less.
Further, it is preferable that the water pressure of the water flow dispersion treatment is 1.0 to 10.0 MPa. By setting the water pressure of the water flow dispersion treatment to 1.0 Mpa or more, it is easy to disperse the single fibers in the state of the single fiber bundle, and by setting the water pressure of the water flow dispersion treatment to 10.0 Mpa or less, the short fiber bundle is excessively made. Since it is not dispersed, it is easy to control the k-nearest neighbor distance ratio value to 10% or more and 80% or less. In addition, the single fibers in the state of single fiber bundles are dispersed, and the water flow locus tends to be inconspicuous. When the water pressure of the water flow dispersion treatment is high, the water flow may penetrate the fiber sheet and is not used as energy to disperse the single fiber bundles. May be done. Further, when the water pressure of the water flow dispersion treatment is high, the fiber sheet tends to have a high density and the texture (rigid / soft value) tends to deteriorate. The water pressure of the dispersion treatment is more preferably 1.5 to 7.0 MPa, still more preferably 2.0 to 4.5 MPa.

As the shape of the water flow discharged from the nozzle hole, it is also preferable to use a plurality of nozzles for discharging the water flow having a disturbance of the water flow of 10% or more. Disturbance is an indicator of fluctuations in the diameter of a stream of water. The disturbance is preferably 12% or more, more preferably 15% or more, because the energy of the water stream can be efficiently converted into the dispersion of fibers. For disturbance, the average diameter of the water flow in the range from 25 mm to 35 mm from the discharge port of the nozzle hole is W, and the standard deviation of the average diameter is σ.
Disturbance (%) = σ (mm) / W (mm) x 100
Calculated by
Although the mechanism of dispersion of the single fiber bundle due to the disturbance has not been clarified, the inventors of the present application have directed the water flow energy in the horizontal direction in addition to the vertical direction of the fiber sheet when the disturbance is large compared to the case where the disturbance is small. It is thought that the dispersion effect will be enhanced because the water flow energy can be efficiently converted into the dispersion energy of the single fiber bundle by making it easy to disperse in multiple directions. As an example, it is considered that at high water pressure, it is easy to take in wasteful water flow energy that penetrates the fiber sheet as dispersed energy.

Further, it is also preferable to make the high-pressure water injection nozzle make a circular motion or to make a reciprocating motion at right angles to the process progress direction (mechanical direction) in order to promote the dispersion of single fibers and improve the feeling of fineness and moistness. ..
The distance from the high-pressure water injection surface to the object to be treated is preferably 5 mm or more and 100 mm or less from the viewpoint of the dispersion effect of the single fiber bundle, the guide cloth before the water flow dispersion treatment, and the process passability during the water flow dispersion treatment. It is more preferably 10 mm or more and 60 mm or less, and further preferably 20 mm or more and 40 mm or less.

[Cross-sectional PU resin area ratio and standard deviation thereof in the cross section of the fiber layer (A) in the thickness direction]
In the artificial leather of the present embodiment, the cross-sectional PU resin area ratio in the cross section of the fiber layer (A) in the thickness direction is 10% or more and 30% or less, and the standard deviation of the cross-sectional PU resin area ratio is 25% or less. ..
When the cross-sectional PU resin area ratio exceeds 30%, the PU resin adhesion ratio becomes too high, and the rubber-like feeling of the artificial leather becomes strong. In this case, the flexibility is reduced and the texture becomes hard. When the artificial leather does not have a scrim, the PU resin area ratio in cross section is 10% or more in that sufficient mechanical properties in the plane direction can be easily obtained. The cross-sectional PU resin area ratio is preferably 15% or more and 30% or less, more preferably 15% or more and 28% or less, and further preferably 15% or more and 26% or less.
The cross-sectional PU resin area ratio is an index of the texture (rigid / soft value) described below in combination with the k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm). For example, when the k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) exceeds 80%, an excess single fiber bundle is present. On the other hand, the water-dispersed PU resin has a high tendency to adhere to a single fiber or a single fiber bundle. That is, if the cross-sectional PU resin area ratio is 10% or more in the presence of an excessive single fiber bundle having a k-nearest neighbor distance ratio value of 80% or more, the PU resin lumps aggregate and adhere to the single fiber bundle. , The texture (rigid and soft value) deteriorates. If the k-nearest neighbor distance ratio value (k = 9, radius r = 20 μm) is 10% or more and 80% or less, and the cross-sectional PU resin area ratio is 10% or more and 30% or less, the texture (rigid / soft value) is It will be 28 cm or less.
As will be described later (see FIG. 6), the cross-sectional PU resin area ratio is obtained by binarizing the PU resin in the SEM image as a black portion, and from the obtained binarized image, the area of the PU resin for each compartment by the partition method. The ratio is calculated and the cross-sectional PU resin area ratio (%) is averaged for all the sections, and the standard deviation is an index of the variation from the average for all the sections. When the standard deviation of the cross-sectional PU resin area ratio is 25% or less, the distribution of the size of the PU resin lump is controlled, so that the variation in texture (rigid / soft value) becomes small. The standard deviation of the cross-sectional PU resin area ratio is preferably 25% or less, more preferably 22% or less, still more preferably 20% or less. The lower limit of the standard deviation of the cross-sectional PU resin area ratio is not particularly limited, and may be 0% or more.
As will be described later, for example, an aqueous dispersion type PU resin dispersion liquid containing hot water-soluble resin fine particles (for example, PVA resin fine particles) is impregnated, and then the PU resin is fixed by heating and filled with the PU resin. By performing the step of obtaining the finished sheet-like material, the cross-sectional PU resin area ratio can be controlled to 10% or more and 30% or less. Further, after a step of forming a fiber web with Kaijima short fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the single fibers of the island component are exposed, the obtained fiber sheet is obtained. By performing the above-mentioned water flow dispersion treatment to obtain a fiber sheet in which single fibers are dispersed, the PU resin adhering to the fibers is also dispersed as the single fibers are dispersed, and as a result, the standard deviation of the cross-sectional PU resin area ratio Can be controlled to 25% or less.

[Average space size]
In the artificial leather of the present embodiment, in the three-dimensional image of the fiber layer (A) by X-ray CT, the diameter of the maximum sphere that enters the space excluding the fibers constituting the fiber layer (A) and the PU resin is used. It is preferable that the average value (average space size) of a certain space size in the thickness direction of the artificial leather is 5 μm or more and 35 μm or less.
As will be described later, the average space size is the largest sphere that enters the space excluding the single fibers and PU resin that make up the fiber layer (A) by taking a three-dimensional image of the fiber layer (A) by X-ray CT. It is an average value in the thickness direction of the diameter (μm) of. The average space size is an index of the dispersed state of the structure composed of the fibers and the PU resin mass in the fiber layer (A) of the artificial leather. When the average space size is large, it means that the fiber and the PU resin mass are present in close contact with each other. When the average space size is within the range of 5 μm or more and 35 μm or less, the fibers and the PU resin are appropriately dispersed, so that the texture (rigidity / softness value) tends to be 28 cm or less. As will be described later, for example, a fiber sheet in which single fibers are dispersed is impregnated with an aqueous dispersion type PU resin dispersion liquid containing hot water-soluble resin fine particles (for example, PVA resin fine particles), and then the PU resin is further impregnated. Is fixed by heating to obtain a fiber sheet filled with PU resin, so that the average space size of the final product, artificial leather, can be controlled to 5 μm or more and 35 μm or less. The average space size is more preferably 5 μm or more and 25 μm or less, and further preferably 5 μm or more and 13 μm or less.

[Adhesion rate of PU resin to fiber sheet]
In the artificial leather of the present embodiment, the adhesion rate of the PU resin to the fiber sheet is preferably 15% by mass or more and 50% by mass or less, more preferably 22% by mass or more and 45% by mass or less, and further preferably 26% by mass. % Or more and 40% by mass or less. The ratio of the PU resin to the fiber sheet affects the controllability of the cross-sectional PU resin area ratio and the average space size described above. When the ratio of PU resin is low, the cross-sectional PU resin area ratio tends to be low, and the average space size tends to be large. On the other hand, when the ratio of PU resin is high, the cross-sectional PU resin area ratio tends to be high and the average space size tends to be small. When the ratio of the PU resin to the fiber sheet is 15% by mass or more, the fibers are well gripped by the PU resin, and it is easy to obtain mechanical strength such as abrasion resistance that satisfies the market needs. On the other hand, when the ratio of the PU resin to the fiber sheet is 50% by mass or less, a flexible texture can be easily obtained.

[Polyurethane (PU) resin]
The PU resin is preferably one obtained by reacting a polymer diol, an organic diisocyanate, and a chain extender.
As the polymer diol, for example, diols such as polycarbonate-based, polyester-based, polyether-based, silicone-based, and fluorine-based diols can be adopted, and a copolymer in which two or more of these are combined may be used. From the viewpoint of hydrolysis resistance, polycarbonate-based or polyether-based diols or combinations thereof are preferably used. Further, from the viewpoint of light resistance and heat resistance, polycarbonate-based, polyester-based, or a combination thereof diol is preferably used. Further, from the viewpoint of cost competitiveness, a diol of a polyether type, a polyester type, or a combination thereof is preferably used.
The polycarbonate-based diol can be produced by a transesterification reaction between an alkylene glycol and a carbonic acid ester, a reaction between a phosgene or a chloraterate and an alkylene glycol, or the like.

Examples of the alkylene glycol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol. Chain alkylene glycol; branched alkylene glycol such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol; 1, Alicyclic diols such as 4-cyclohexanediol; aromatic diols such as bisphenol A; and the like can be mentioned, and these can be used alone or in combination of two or more.
Examples of the polyester-based diol include a polyester diol obtained by condensing various low molecular weight polyols with a polybasic acid.
Examples of low molecular weight polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-propane. Diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, cyclohexane One or more selected from -1,4-dimethanol can be used. Further, an adduct in which various alkylene oxides are added to bisphenol A can also be used.
Examples of polybasic acids include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecandicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro. One or more selected from the group consisting of isophthalic acid can be mentioned.

Examples of the polyether diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and a copolymer diol in which they are combined.
The number average molecular weight of the polymer diol is preferably 500 to 4000. By setting the number average molecular weight to 500 or more, more preferably 1500 or more, it is possible to prevent the texture from becoming hard. Further, by setting the number average molecular weight to 4000 or less, more preferably 3000 or less, the strength of the PU resin can be maintained satisfactorily.
Examples of the organic diisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate; aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate; and combinations thereof. May be used. Of these, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferably used from the viewpoint of light resistance.
As the chain extender, an amine-based chain extender such as ethylenediamine and methylenebisaniline, or a diol-based chain extender such as ethylene glycol can be used. Further, a polyamine obtained by reacting polyisocyanate with water can also be used as a chain extender.

The PU resin is used in the form of a solvent-type PU resin in which the PU resin is dissolved in an organic solvent such as N, N-dimethylformamide, and an aqueous dispersion-type PU resin in which the PU resin is emulsified with an emulsifier and dispersed in water. it can. Above all, it is easy to fill the fiber sheet with PU resin in a fine form, it is easy to obtain the required performance as artificial leather such as texture and mechanical properties even with a small amount of adhesion, and there is no need to use an organic solvent, which reduces the environmental load. A water-dispersed PU resin is preferable because it can be reduced. That is, since the water-dispersed PU resin can be impregnated in the fiber sheet in the form of a dispersion liquid in which the PU resin is dispersed with a desired particle size (hereinafter, also referred to as PU resin dispersion liquid), the particle size is controlled. Therefore, the filling form of the PU resin in the fiber sheet can be satisfactorily controlled.
As the water-dispersible PU resin, a self-emulsifying PU resin containing a hydrophilic group in the PU molecule, a forced emulsifying PU resin obtained by emulsifying the PU resin with an external emulsifier, or the like can be used.
A cross-linking agent can be used in combination with the water-dispersible PU resin for the purpose of improving durability such as moisture heat resistance, abrasion resistance, and hydrolysis resistance. It is preferable to add a cross-linking agent in order to improve durability during liquid flow dyeing, suppress fiber shedding, and obtain excellent surface quality. The cross-linking agent may be an external cross-linking agent added as an additive component to the PU resin, or an internal cross-linking agent in which a reactive group capable of forming a cross-linked structure in advance in the PU resin structure is introduced.
The water-dispersible PU resin used for artificial leather generally has a crosslinked structure in order to have resistance to dyeing processing, and therefore tends to be difficult to dissolve in an organic solvent such as N, N-dimethylformamide. .. Therefore, for example, when artificial leather is immersed in N, N-dimethylformamide at room temperature for 12 hours to dissolve the PU resin, and then the cross section is observed with an electron microscope or the like, it is in the form of a resin having no fiber shape. If the substance remains, it can be determined that the resinous substance is an aqueous dispersion type PU resin.

In a preferred embodiment, the PU resin is filled with the PU resin dispersion liquid from the viewpoint of easily controlling the cross-sectional PU resin area ratio, its standard deviation, and the average space size, and at that time, in the dispersion liquid. The average primary particle size of the PU resin is preferably 0.1 μm or more and 0.8 μm or less, more preferably 0.1 μm or more and 0.6 μm or less, and further preferably 0.2 μm or more and 0.5 μm or less. The average primary particle size is a value obtained by measuring the PU resin dispersion liquid with a laser-type diffraction type particle size distribution measuring device (“LA-920” manufactured by HORIBA, Ltd.). By setting the average primary particle size of the PU resin to 0.1 μm or more, the force for gripping the fibers in the fiber sheet by the PU resin (that is, the binder force) is improved, so that the artificial leather has excellent mechanical strength. Is obtained. Further, setting the average primary particle size of the PU resin to 0.8 μm or less is advantageous in that it suppresses aggregation or coarsening of the PU resin and the standard deviation of the cross-sectional PU resin area ratio can be controlled to 25% or less. Is. By setting the average primary particle size of the PU resin in the PU resin dispersion to 0.1 μm or more and 0.8 μm or less, the fibers constituting the artificial leather (particularly its surface layer) are often gripped with each other, which is flexible. Texture (rigidity and softness value) and excellent mechanical strength (wear resistance, etc.) can be obtained.

[Solid content concentration of PU resin dispersion]
As will be described later, in a typical embodiment, the PU resin is impregnated in the form of an impregnating liquid such as a solution (for example, in the case of a solvent-soluble type) or a dispersion liquid (for example, in the case of an aqueous dispersion type). For example, the solid content concentration of the aqueous dispersion type PU resin dispersion liquid can be 10% by weight or more and 35% by weight or less, more preferably 15 to 30% by mass, and further preferably 15 to 25% by mass. In one embodiment, the impregnating liquid is prepared and the fiber sheet is impregnated so that the adhesion ratio of the PU resin to 100% by mass of the fiber sheet is 15% by mass or more and 50% by mass or less.

The impregnating liquid containing the PU resin (for example, water-dispersible PU resin) may contain stabilizers (ultraviolet absorbers, antioxidants, etc.), flame retardants, antistatic agents, pigments (carbon black, etc.), etc., if necessary. Additives may be added. The total amount of these additives present in the artificial leather is, for example, 0.1 to 10.0 parts by mass, 0.2 to 8.0 parts by mass, or 0.3 to 0.3 to 100 parts by mass of the PU resin. It may be 6.0 parts by mass. Such additives will be distributed in the PU resin of artificial leather. In the present disclosure, the values when referring to the size of the PU resin and the mass ratio to the fiber sheet are intended to include the additives (when used).

[Hot water-soluble resin fine particles]
When the fiber sheet is filled with the PU resin by impregnating the fiber sheet with an impregnating solution containing the PU resin, the fiber sheet is impregnated with the water-dispersible PU resin dispersion containing the hydrothermally soluble resin fine particles, and then the fiber sheet is impregnated with the water-dispersible PU resin dispersion. It is a preferable embodiment that the PU resin is fixed by heating to obtain a sheet-like material filled with the PU resin. In the post-step or dyeing step, by removing the hot water-soluble resin fine particles from the obtained fiber sheet using hot water, a part of the continuous layer of the PU resin is divided and made porous, and the PU resin adheres. The effect of refining the state can be obtained.
Examples of the hot water-soluble resin fine particles include partially saponified PVA resin fine particles and fully saponified PVA resin fine particles. Since the fully saponified PVA resin fine particles tend to be less likely to be eluted in water at room temperature (20 ° C) than the partially saponified PVA resin fine particles, the fully saponified PVA resin fine particles are used as the hot water soluble resin fine particles. Is preferable. From the viewpoint that it is difficult to elute in water at room temperature (20 ° C.), the degree of saponification of the fully saponified PVA resin fine particles is preferably 95 mol% or more, and more preferably 98 mol% or more. The average particle size (size) of the hydrothermally soluble resin fine particles is preferably 1 μm or more and 8 μm or less, more preferably 2 μm or more and 6 μm or less, in order to achieve both the force of adhering and gripping the fibers and the miniaturization of the adhered state of the PU resin. More preferably, it is 2 μm or more and 4 μm or less. By setting the average particle size to 1 μm or more, the hydrothermally soluble resin fine particles are less likely to aggregate, and by setting the average particle size to 8 μm or less, the hydrothermally soluble resin fine particles are easily impregnated into the fiber sheet. .. "NL-05" manufactured by Mitsubishi Chemical Corporation can be used as the fine particles, and the miniaturization of the hot water-soluble resin fine particles can be achieved by the method described in JP-A-7-82384.
The content of the hot water-soluble resin fine particles in the water-dispersible PU resin dispersion is preferably 1% by weight or more and 20% by weight or less, more preferably 2% by weight or more and 15% by weight or less, and further. It is preferably 3% by weight or more and 10% by weight or less. When the hydrothermally soluble resin fine particles are contained in the water-dispersible PU resin dispersion liquid in an amount of 1% by mass or more, the dispersion of the PU resin mass is likely to be promoted. On the other hand, when the hydrothermally soluble resin fine particles are contained in the water-dispersed PU resin dispersion liquid in an amount of 20% by weight or less, the fine particles do not aggregate and the stability of the dispersion liquid is easily maintained.
In the present specification, the "hot water-soluble resin" refers to a resin that is sparingly soluble in room temperature water.

[Hot water soluble resin]
When the fiber sheet is impregnated with an aqueous dispersion type PU resin dispersion containing hot water-soluble resin fine particles and then fixed by heating to obtain a sheet-like material filled with the PU resin, the fiber sheet is coated. Before impregnating the water-dispersible PU resin dispersion liquid containing the hot-water-soluble resin fine particles, a step of adhering the hot-water-soluble resin to the fiber sheet can be performed. As a method for adhering the hot water-soluble resin (for example, PVA resin), a hot water-soluble resin aqueous solution can be prepared, the aqueous solution can be impregnated into the fiber sheet, and then dried. In the post-step or dyeing step, the hot-water-soluble resin fine particles and the hot-water-soluble resin are removed from the obtained fiber sheet using hot water to prevent the adhesion between the fiber and the PU resin. Since a part of the continuous layer of the PU resin is divided and made porous to obtain the effect of making the adhered state of the PU resin finer, the texture of the artificial leather is likely to be improved.
Examples of the hot water-soluble resin include partially saponified PVA resin and fully saponified PVA resin. Since the fully saponified PVA resin tends to be less likely to be eluted in water at room temperature (20 ° C.) than the partially saponified PVA resin, it is preferable to use the fully saponified PVA resin as the hydrothermally soluble resin. From the viewpoint that it is difficult to elute in water at room temperature (20 ° C.), the saponification degree of the fully saponified PVA resin is preferably 95 mol% or more, more preferably 98 mol% or more. Further, in order to enhance the permeability of the hot water-soluble resin aqueous solution at the time of impregnation, the degree of polymerization is preferably 1000 or less, more preferably 700 or less.

[Fiber sheet]
As shown in FIG. 1, the fiber sheet 1 includes at least the fiber layer (A) 12, and the scrim 11 and the fiber layer (B) 13 are optional and are not essential elements. Therefore, in the case of the artificial leather of the present embodiment, in the case of a single layer of the fiber layer (A), in the case of two layers of the fiber layer (A) and the scrim or the fiber layer (B), the fiber layer (A), the scrim and the fiber There are cases where there are three layers (B).
When the scrim 11 and / or the fiber layer (B) 13 is not included, the fiber layer (A) may be a half-cut single-layer fiber sheet filled with PU resin, as will be described later. In one aspect, the fiber sheet has a scrim-free, single-layer structure. This is because halving increases productivity.
In another aspect, the fiber sheet has a three-layer structure and the scrim is an intermediate layer. For example, a scrim 11 which is a woven or knitted fabric is formed between the fiber layer (A) 12 which constitutes the first outer surface of the artificial leather and the fiber layer (B) 13 which constitutes the second outer surface of the artificial leather. A three-layer structure in which fibers are sandwiched between these layers and sandwiched in a sandwich shape is preferable in terms of dimensional stability, tensile strength, tear strength, and the like. Further, according to the three-layer structure of the fiber layer (A), the fiber layer (B), and the scrim sandwiched between them, the fiber layer (A) and the fiber layer (B) can be individually designed. , It is preferable that the diameter, type, etc. of the fibers constituting these layers can be freely customized according to the functions and applications required for artificial leather. For example, if ultrafine fibers are used for the fiber layer (A) and flame-retardant fibers are used for the fiber layer (B), both excellent surface quality and high flame retardancy can be achieved at the same time.

When the fiber sheet contains a scrim, the scrim, which is a woven or knitted fabric, is preferably made of the same polymer system as the fibers constituting the fiber layer (A) from the viewpoint of the same color due to dyeing. For example, if the fibers constituting the fiber layer (A) are polyester-based, the fibers constituting the scrim are also preferably polyester-based, and if the fibers constituting the fiber layer (A) are polyamide-based, the scrim is used. The constituent fibers are also preferably polyamide-based. In the case of knitting, the scrim is preferably a single knit knitted at 22 gauge or more and 28 gauge or less. When the scrim is a woven fabric, higher dimensional stability and strength than knitted fabric can be achieved. The structure of the woven fabric may be plain weave, twill weave, satin weave or the like, but plain weave is preferable from the viewpoint of cost and process such as entanglement.
The threads constituting the woven fabric may be monofilaments or multifilaments. The single fiber fineness of the yarn is preferably 5.5 dtex or less in that a flexible artificial leather can be easily obtained. As the form of the yarn constituting the woven fabric, it is preferable that a raw silk of multifilament such as polyester or polyamide or a processed yarn subjected to false twisting is twisted at a twist number of 0 to 3000 T / m. The multifilament may be a normal one, for example, 33dtex / 6f, 55dtex / 24f, 83dtex / 36f, 83dtex / 72f, 110dtex / 36f, 110dtex / 48f, 167dtex / 36f, 166dtex / 48f and the like of polyester, polyamide and the like. It is preferably used. The threads constituting the woven fabric may be multifilament long fibers. The weaving density of the threads in the woven fabric is preferably 30 to 150 threads / inch, more preferably 40 to 100 threads / inch, in order to obtain an artificial leather that is flexible and has excellent mechanical strength. In order to have good mechanical strength and appropriate texture, the basis weight of the woven fabric is preferably ^{20 to 150 g / m 2.} The presence or absence of false twisting in the woven fabric, the number of twists, the single fiber fineness of the multifilament, the weaving density, etc. are the interrelated characteristics of the fiber layer (A) and the fibers constituting the fiber layer (B) which is an arbitrary layer. In addition to the flexibility of artificial leather, it also contributes to mechanical properties such as seam strength, tear strength, tensile strength and elongation, and elasticity. Therefore, it may be appropriately selected according to the target physical properties and application.

From the viewpoint of obtaining an artificial leather having a higher level of abrasion resistance, dyeability, and surface quality, the artificial leather of the present embodiment has a fiber layer (A) composed of fibers having an average diameter of 1 μm or more and 8 μm or less. It is preferably 2 μm or more and 6 μm or less, and more preferably 2 μm or more and 5 μm or less. When the average diameter of the fibers is 1 μm or more, the abrasion resistance, the color-developing property by dyeing, and the light fastness are good. On the other hand, when the average diameter of the fibers is 8 μm or less, since the number of fibers is high, the feeling of fineness is high, the surface feel is smooth, and artificial leather with better surface quality can be easily obtained.

Examples of the fibers constituting the fiber layer (fiber layer (A), fiber layer (B) as an arbitrary layer, and additional layer) constituting the artificial leather include polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate. Synthetic fibers such as polyester fibers; boliamide fibers such as nylon 6, nylon 66, and nylon 12; are suitable. Among them, polyethylene terephthalate is preferable because the fibers themselves do not yellow even when exposed to direct sunlight for a long time and have excellent dyeing fastness, considering applications requiring durability such as in the car seat field. .. Further, from the viewpoint of reducing the environmental load, as the fiber constituting the fiber layer constituting the artificial leather, polyethylene terephthalate obtained by chemical recycling or material recycling, polyethylene terephthalate using a plant-derived raw material, or the like is more preferable.

In the present specification, the term "single fiber dispersed" means that the fiber does not form a fiber bundle like the island component in the sea-island type composite fiber described below. For example, ultrafine fiber-generating fibers such as sea-island type composite fibers (for example, copolymerized polyester as a sea component and regular polyester as an island component) are used to form a three-dimensional entanglement with a scrim, and then fine fibers. The fibers obtained by the chemical treatment (removing the sea component of the sea-island type composite fiber by dissolution, decomposition, etc.) are present as fiber bundles in the fiber layer (A) and are not dispersed as single fibers. As an example, a sea-island type composite short fiber having an island component equivalent to a single fiber fineness of 0.2 dtex and 24 islands / 1 f is produced, a fiber layer (A) is formed from the sea-island type composite short fiber, and then needle punching or the like is performed. By forming a three-dimensional confounding body with the scrim, filling the three-dimensional confounding body with PU resin, and then dissolving or decomposing the sea component, ultrafine fibers having a single fiber fineness equivalent to 0.2 dtex can be obtained. In this case, 24 single fibers are present in the fiber layer (A) in a state of a converged fiber bundle (corresponding to 4.8 dtex in the converged state).

When the fiber layer (A) is composed of fibers in which single fibers are dispersed, the surface smoothness is excellent. For example, when the outer surface of the fiber layer (A) is raised by buffing or the like, uniform raising is performed. Even when it is easy to obtain and the adhesion rate of the PU resin is relatively low, it is difficult for a fluffy appearance called pilling to occur due to friction, so that an artificial leather having better surface quality and abrasion resistance can be obtained. Further, when the fibers are dispersed as single fibers, the fiber spacing is narrow and tends to be uniform, so that good wear resistance can be obtained even if the PU resin is adhered in a fine form. As a method of dispersing the fibers as a single fiber, a method of forming a fiber sheet by a papermaking method from a fiber produced by a direct spinning method, or a method of dissolving or decomposing a sea component of a fiber sheet produced of a sea-island type composite fiber to form an ultrafine fiber bundle. The above-mentioned water flow dispersion treatment is applied to the surface of the ultrafine fiber bundle after the above-mentioned water flow dispersion treatment is performed to promote the monofilament of the ultrafine fiber bundle.

Among the fiber layers constituting the artificial leather, the fibers may or may not be dispersed as single fibers in the fiber layers other than the fiber layer (A), but in a preferred embodiment, the layers other than the fiber layer (A) are used. Is also composed of fibers in which single fibers are dispersed. Since the fibers constituting the layers other than the fiber layer (A) are dispersed as single fibers, the thickness of the artificial leather becomes uniform, the processing accuracy is improved, and the quality is stabilized. It is preferable from the viewpoint of homogenizing the appearance of the leather.

If artificial leather is composed only of fibrous layers (A), basis weight of the fiber constituting the fiber layer (A), from the viewpoint of mechanical strength such as abrasion resistance, preferably 40 g / m ² or more 500 g / m ² Below, it is more preferably 50 g / m ² or more and 370 g / m ² or less, and further preferably 60 g / m ² or more and 320 g / m ² or less.
When the artificial leather is composed of a fiber layer (A), a scrim, and a fiber layer (B) three-layer structure, the texture of the fibers constituting the fiber layer (A) is determined from the viewpoint of mechanical strength such as abrasion resistance. It is preferably 10 g / m ² or more and 200 g / m ² or less, more preferably 30 g / m ² or more and 170 g / m ² or less, and further preferably 60 g / m ² or more and 170 g / m ² or less. The basis weight of the fibers constituting the fiber layer (B) is preferably 10 g / m ² or more and 200 g / m ² or less, more preferably 20 g / m ² or more and 170 g / m from the viewpoint of cost and ease of manufacture. It can be ^{2 or less.} ^{The basis weight of the scrim is preferably 20 g / m 2} or more and 150 g / m ² or less, more preferably 20 g / m ² or more and 130 g / m ² or less, still more preferably, from the viewpoint of mechanical strength and the entanglement between the fiber layer and the scrim. Is 30 g / m ² or more and 110 g / m ² or less.
The texture of the artificial leather filled with PU resin is preferably 50 g / m ² or more and 550 g / m ² or less, more preferably 60 g / m ² or more and 400 g / m ² or less, and further preferably 70 g / m ² or more and 350 g / m. ² or less.

In one embodiment, the texture (rigidity / softness value) of the artificial leather is preferably 28 cm or less, more preferably 6 cm or more and 26 cm or less, and further preferably 8 cm or more and 22 cm or less. The stiffness value is an index showing the texture of artificial leather. By setting the rigidity and softness value to 28 cm or less, the moldability of the skin material or interior material of the seats of interiors, automobiles, aircraft, railroad vehicles, etc. is improved, and the consumption performance is also improved, which is required by the market for flexibility. Easy to meet your needs.

In one aspect, the denseness of the artificial leather (dispersibility of the fiber bundle) is preferably 4.0 grade or higher, more preferably 5.0 grade or higher. The feeling of fineness (dispersity of fiber bundles) is a value obtained by determining the fineness of raising in 7 stages by sensory evaluation by visual inspection and tactile sensation. By setting the feeling of precision to 4.0 grade or higher, the quality of the seats of interiors, automobiles, aircrafts, railroad vehicles, etc. as skin materials or interior materials is improved.

<Manufacturing method of artificial leather>
Hereinafter, an example of a method for producing artificial leather according to the present embodiment will be described.
An example of the method for producing artificial leather of the present embodiment is as follows:
A step of forming a fiber web from Kaijima short fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the island component single fibers are exposed; and water flow dispersion on the obtained fiber sheet. The process of applying treatment to obtain a fiber sheet in which single fibers are dispersed;
Can include the following steps:
The fiber sheet in which the single fibers are dispersed is impregnated with an aqueous dispersion type PU resin dispersion liquid containing hot water-soluble resin fine particles, and then the PU resin is fixed by heating to form a sheet filled with the PU resin. And a step of removing the hot water-soluble resin fine particles from the obtained sheet-like material using hot water;
Can be further included.
Hereinafter, each step will be described in order.

[A process of forming a fiber web with short sea island fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the single fibers of the island component are exposed]
As a method for producing each fiber layer (fiber layer (A), arbitrary fiber layer (B), etc.) constituting the fiber sheet of artificial leather, a spinning direct connection method (for example, a spunbond method and a melt blown method) or a melt blown method or , A method of forming a fiber sheet using short fibers (for example, a dry method such as a carding method and an airlaid method, and a wet method such as a spinning method) can be preferably used. In embodiments, carding (SIF) short fibers are used as the raw material. A fiber sheet produced using short fibers is suitable in terms of improving the surface quality of artificial leather because it has small basis weight spots, is excellent in uniformity, and is easy to obtain uniform raising.

As a means for forming the ultrafine fibers of the fiber sheet, ultrafine fiber-expressing fibers can be used. By using the ultrafine fiber-expressing type fiber, a morphology in which the ultrafine fiber bundles are entangled can be stably obtained.
As the ultrafine fiber-expressing type fiber, a sea-island type in which two components of thermoplastic resins having different solvent solubility are used as a sea component and an island component, and the sea component is dissolved and removed using a solvent or the like to form an island component as an ultrafine fiber. It is possible to employ a peelable composite fiber in which fibers or two-component thermoplastic resins are alternately arranged radially or in a multilayer shape on a fiber cross section, and each component is separated and divided into ultrafine fibers. Among them, the sea-island type fiber is preferably used from the viewpoint of the flexibility and texture of the sheet-like material because it is possible to impart appropriate voids between the island components, that is, between the ultrafine fibers by removing the sea component. ..
For the sea island type fiber, a sea island type composite base is used, and the sea island type composite fiber is spun by mutually arranging the two components of the sea component and the island component, and the sea island is spun by mixing the two components of the sea component and the island component. There are mold mixed fibers and the like. The sea-island type composite fiber is preferably used from the viewpoint that ultrafine fibers having a uniform fineness can be obtained and that ultrafine fibers having a sufficient length can be obtained and contribute to the strength of the sheet-like material.
As the sea component of the sea-island type fiber, copolymerized polyester obtained by copolymerizing polyethylene, polypropylene, polystyrene, sodium sulfoisophthalic acid, polyethylene glycol, or the like, polylactic acid, or the like can be used. Among them, from the viewpoint of environmental consideration, copolymerized polyesters and polylactic acids obtained by copolymerizing alkali-degradable sodium sulfoisophthalic acid, polyethylene glycol, etc., which can be decomposed without using an organic solvent, are preferable.
When the sea-island type fiber is used, the desealing treatment is preferably performed before the PU resin is applied to the fiber sheet. If the desealing treatment is performed before the PU resin is applied, the PU resin is in direct contact with the ultrafine fibers and the ultrafine fibers can be strongly gripped, so that the abrasion resistance of the sheet-like material is improved.

As a method of entwining fibers or fiber bundles of fiber webs, sea-island type fibers are cut to a predetermined fiber length to form staples, fiber webs are formed through curds and cross wrappers, and water flow entanglement treatment called needle punching or spunlacing method is performed. A method of entanglement can be adopted.
In the needle punching method, the number of barbs of the needles used is preferably 1 to 9. By setting the number of barbs to one or more, an entanglement effect can be obtained and damage to the fibers can be suppressed. By reducing the number of barbs to 9 or less, damage to the fibers can be reduced, and needle marks remaining on the artificial leather can be reduced, so that the appearance of the product can be improved.
Considering the entanglement of fibers and the influence on the appearance of the product, the total depth of the barb (the length from the tip of the barb to the bottom of the barb) is preferably 0.05 mm or more and 0.10 mm or less. When the total depth of the barb is 0.05 mm or more, good hooking on the fibers can be obtained, so that efficient fiber entanglement is possible. Further, when the total depth of the barb is 0.10 mm or less, the needle marks remaining on the artificial leather are reduced, and the quality is improved. Considering the balance between the strength of the barb portion and the fiber entanglement, the total depth of the barb is more preferably 0.06 mm or more and 0.08 mm or less.
When the fibers are entangled by the needle punch method, the punch density range is preferably 300 lines / cm ² or more and 6000 lines / cm ² or less, and 1000 lines / cm ² or more and 6000 lines / cm ² or less. Is more preferable.
The fiber sheet obtained by the needle punching treatment can be, for example, immersed in water at a temperature of 98 ° C. for 2 minutes to shrink, and dried at a temperature of 100 ° C. for 5 minutes to obtain a fiber sheet before desealing. ..
The desealing treatment can be performed by immersing the sea-island type fiber in a solvent and constricting the liquid. As the solvent for dissolving the sea component, an alkaline aqueous solution such as sodium hydroxide can be used when the sea component is a copolymerized polyester or polylactic acid. From the viewpoint of environmental consideration of the process, desea treatment with an alkaline aqueous solution such as sodium hydroxide is preferable.

When selecting a method using short fibers (staples), the short fiber length is a dry method (carding method, airlaid method, etc.), preferably 13 mm or more and 102 mm or less, more preferably 25 mm or more and 76 mm or less, and further preferably. It is 38 mm or more and 76 mm or less, and is preferably 1 mm or more and 30 mm or less, more preferably 2 mm or more and 25 mm or less, and further preferably 3 mm or more and 20 mm or less in a wet method (papermaking method or the like). For example, the aspect ratio (L / D), which is the ratio of the length (L) to the diameter (D), of the short fibers used in the wet method (papermaking method, etc.) is preferably 500 or more and 2000 or less, more preferably. It is 700 to 1500. Such an aspect ratio means that when the short fibers are dispersed in water to prepare a slurry, the dispersibility and openness of the short fibers in the slurry are good, and the fiber layer strength is good. Compared with the dry method, the fiber length is short and the single fibers are easily dispersed, so that it is difficult to obtain a fluffy appearance called pilling due to friction, which is preferable. For example, the fiber length of a short fiber having a diameter of 4 μm is preferably 2 mm or more and 8 mm or less, and more preferably 3 mm or more and 6 mm or less.

[Step of subjecting the obtained fiber sheet to water flow dispersion treatment to obtain a fiber sheet in which single fibers are dispersed]
By subjecting the obtained fiber sheet to the above-mentioned water flow dispersion treatment, a fiber sheet in which single fibers are dispersed can be obtained. By carrying out the above-mentioned water flow dispersion treatment after the sea removal step, the k proximity distance ratio value (k = 9, radius) between the single fiber cross sections constituting the fiber layer (A) in the thickness direction cross section of the artificial leather r = 20 μm) can be controlled to 80% or less.

[The fiber sheet in which the single fibers are dispersed is impregnated with an aqueous dispersion type PU resin dispersion liquid containing hot water-soluble resin fine particles, and then the PU resin is fixed by heating to form a sheet filled with the PU resin. Process of obtaining things]
In this step, the fiber sheet is impregnated with an aqueous dispersion type PU resin dispersion liquid containing hot water-soluble resin fine particles, and then the PU resin is fixed by heating to fill the PU resin. In a typical embodiment, the PU resin is impregnated in the form of an impregnating solution such as a dispersion (for example, in the case of an aqueous dispersion). The concentration of the PU resin in the impregnating liquid can be, for example, 10 to 35% by mass. In one embodiment, the impregnating liquid is prepared and the fiber sheet is impregnated so that the ratio of the PU resin to 100% by mass of the fiber sheet is 15 to 50% by mass.

The water-dispersed PU resin is a forced emulsified PU resin that is forcibly dispersed and stabilized by using a surfactant, and has a hydrophilic structure in the PU molecular structure, and is in water even in the absence of the surfactant. It is classified as a self-emulsifying PU resin that disperses and stabilizes. Any of these may be used in this embodiment, but it is preferable to use a forced emulsified PU resin from the viewpoint of imparting heat-sensitive coagulation properties, which will be described later.
In the present embodiment, the fiber sheet is impregnated with the water-dispersed PU resin dispersion liquid containing the hot water-soluble resin fine particles, but it is not preferable that the hot water-soluble resin fine particles are dissolved in the water-dispersed PU resin dispersion liquid. On the other hand, since the hot water-soluble resin fine particles show a property that the aqueous solution in which the surfactant is dissolved is more difficult to dissolve than water, the forced emulsified PU resin dispersion liquid containing the surfactant is the interface. This is a preferred embodiment over the self-emulsifying PU resin dispersion liquid that does not contain an activator. The concentration of the water-dispersed PU resin (the content of the PU resin in the water-dispersed PU resin dispersion liquid) controls the amount of adhesion of the water-dispersed PU resin, and the high concentration promotes the aggregation of the PU resin. From the viewpoint that the stability of the impregnating liquid is lowered, it is preferably 10 to 35% by mass, more preferably 15 to 30% by mass, and further preferably 15 to 25% by mass.
Further, as the water-dispersed PU resin dispersion liquid, one having heat-sensitive coagulation property is preferable. By using a water-dispersed PU resin dispersion having heat-sensitive coagulation properties, the PU resin can be uniformly applied in the thickness direction of the fiber sheet. The heat-sensitive coagulation property refers to a property in which the fluidity of the PU resin dispersion liquid decreases and solidifies when a certain temperature (heat-sensitive coagulation temperature) is reached when the PU resin dispersion liquid is heated. In the production of a sheet-like material filled with PU resin, a fiber sheet is impregnated with a PU resin dispersion liquid, and then the fiber is coagulated by dry heat coagulation, moist heat coagulation, hot water coagulation, or a combination thereof and dried. Apply PU resin to the sheet. Dry coagulation is a realistic method for coagulating an aqueous dispersion type PU resin dispersion that does not exhibit heat-sensitive coagulation in industrial production, but in that case, a migration phenomenon in which the PU resin is concentrated on the surface layer of a sheet-like material occurs. The texture of the sheet-like material that is generated and filled with PU resin tends to be cured.
The heat-sensitive solidification temperature of the water-dispersed PU resin dispersion is preferably 40 to 90 ° C. By setting the heat-sensitive solidification temperature to 40 ° C. or higher, the stability of the PU resin dispersion liquid during storage becomes good, and the adhesion of PU resin to the machine during operation can be suppressed. Further, by setting the heat-sensitive solidification temperature to 90 ° C. or lower, the migration phenomenon of the PU resin in the fiber sheet can be suppressed.
In order to keep the heat-sensitive coagulation temperature as described above, a heat-sensitive coagulant may be added as appropriate. Examples of the heat-sensitive coagulant include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate and calcium chloride, and radical reaction initiation of sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, benzoyl peroxide and the like. Agents can be mentioned.

A water-dispersed PU resin dispersion can be impregnated and applied to a fiber sheet to coagulate the PU resin by dry heat coagulation, moist heat coagulation, hot water coagulation, or a combination thereof. The temperature of the moist heat coagulation is preferably 40 to 200 ° C., which is equal to or higher than the heat-sensitive coagulation temperature of the PU resin. By setting the temperature of moist heat coagulation to 40 ° C. or higher, more preferably 80 ° C. or higher, the time until solidification of the PU resin can be shortened and the migration phenomenon can be further suppressed. On the other hand, by setting the temperature of moist heat coagulation to 200 ° C. or lower, more preferably 160 ° C. or lower, thermal deterioration of the PU resin or PVA resin can be prevented. The temperature of hot water coagulation is preferably 40 to 100 ° C., which is equal to or higher than the heat-sensitive coagulation temperature of the PU resin. By setting the temperature of hot water solidification in hot water to 40 ° C. or higher, more preferably 80 ° C. or higher, the time until solidification of the PU resin can be shortened and the migration phenomenon can be further suppressed. The dry solidification temperature and the drying temperature are preferably 80 to 180 ° C. Productivity is excellent by setting the dry solidification temperature and the drying temperature to 80 ° C. or higher, more preferably 90 ° C. or higher. On the other hand, by setting the dry solidification temperature and the drying temperature to 180 ° C. or lower, more preferably 160 ° C. or lower, thermal deterioration of the PU resin or PVA resin can be prevented.
As described above, when the fiber sheet in which the single fibers are dispersed is impregnated with the water-dispersed PU resin dispersion liquid containing the hot water-soluble resin fine particles, the hot water dissolution in the water-dispersed PU resin dispersion liquid is performed. The content of the sex resin fine particles is preferably 1% by weight or more and 20% by weight or less, more preferably 2% by weight or more and 15% by weight or less, and further preferably 3% by weight or more and 10% by weight or less. The inclusion of the hot water-soluble resin fine particles in the water-dispersible PU resin dispersion promotes further dispersion of the PU resin mass.

[Step of removing the hot water-soluble resin fine particles from the obtained sheet-like material using hot water]
As a means for removing the hot water-soluble resin from the sheet, for example, a method of immersing in hot water at 60 ° C. or higher, preferably 80 ° C. or higher, or 80 ° C. or higher before performing the dyeing process in the liquid flow dyeing machine. Examples thereof include a method of removing hot water-soluble resin fine particles while circulating hot water. In particular, the method of removing the hot water-soluble resin fine particles in the liquid flow dyeing machine can omit the steps of drying and winding the sheet-like material after removing the hot water-soluble resin fine particles, and can improve the production efficiency. Is preferable. In the present embodiment, a flexible sheet-like material is obtained by removing the hot water-soluble resin fine particles from the sheet-like material after applying the PU resin. The method for removing the hot water-soluble resin fine particles is not particularly limited, but it is preferable to dissolve and remove the sheet by, for example, immersing the sheet in hot water at 60 to 100 ° C. and squeezing it with a mangle or the like as necessary. It is an aspect.

[Post-process]
After filling the fiber sheet with PU resin and removing the hot water-soluble resin fine particles, if the scrim is not contained, the sheet-like material filled with PU resin can be cut in half in the sheet thickness direction. Thereby, the production efficiency can be improved.
Further, a lubricant such as a silicone dispersion may be applied to the sheet-like material filled with the PU resin before the raising treatment described later. Further, it is a preferable embodiment to apply an antistatic agent before the raising treatment in order to prevent the grinding powder generated from the sheet-like material by grinding from being deposited on the sandpaper.
Raising treatment can be performed to form fluff on the surface of the sheet-like material. The raising treatment can be performed by a method of grinding using sandpaper, a roll sander, or the like. Further, by applying silicone or the like as a lubricant before the raising treatment, raising by surface grinding becomes possible easily, and the surface quality becomes very good.
The artificial leather is preferably dyed for the purpose of enhancing the value of the sensory surface (that is, the visual effect). The dye may be selected according to the type of fiber constituting the fiber sheet. For example, a disperse dye can be used for polyester fibers, and an acid dye or gold-containing dye can be used for polyamide fibers. And further combinations thereof can be used. When dyed with a disperse dye, reduction cleaning may be performed after dyeing. As the dyeing method, a usual method well known to dyeing processors can be used. As a dyeing method, it is preferable to use a liquid flow dyeing machine because the sheet-like material can be dyed and at the same time a kneading effect can be given to soften the sheet-like material. The dyeing temperature is preferably 80 to 150 ° C., although it depends on the type of fiber. By setting the dyeing temperature to 80 ° C. or higher, more preferably 110 ° C. or higher, dyeing to the fibers can be efficiently performed. On the other hand, by setting the dyeing temperature to 150 ° C. or lower, more preferably 130 ° C. or lower, deterioration of the PU resin can be prevented.
It is preferable that the artificial leather dyed in this manner is subjected to soaping and, if necessary, reduction cleaning (that is, cleaning in the presence of a chemical reducing agent) to remove excess dye. It is also a preferred embodiment to use a dyeing aid at the time of dyeing. By using a dyeing aid, the uniformity and reproducibility of dyeing can be improved. In addition, a finishing agent treatment using a softener such as silicone, an antistatic agent, a water repellent agent, a flame retardant, a light resistant agent, an antibacterial agent, etc. can be applied in the same bath as the dyeing or after the dyeing.

The artificial leather of the present embodiment is an interior material, a shirt, a jacket, and a casual material having a very elegant appearance as a skin material for seats, ceilings, interiors, etc. in the vehicle interior of furniture, chairs, wall materials, automobiles, trains, aircraft, etc. Shoes, sports shoes, men's shoes, women's shoes and other shoe uppers, trims, bags, belts, wallets, etc., clothing materials used for some of them, wiping cloth, polishing cloth, CD curtains, and other industrial materials. Can also be preferably used.

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the Examples do not limit the scope of the present invention. The physical characteristics, quality, etc. of the artificial leather samples according to the examples and comparative examples were evaluated by the following procedures and methods.

(1) Sample collection location Fig. 3 shows the sample collection location.
First, 10 points (sampling areas 1, 2, ...) In the mechanical direction (MD) of the fiber layer (A) or the artificial leather including the fiber layer (A) are cut out in a strip shape (indicated by a dotted line). A cross section in the thickness (t) direction is prepared in each sampling region. The prepared cross section in the thickness (t) direction is conductively treated by coating an osmium atom with 1 nm. In this cross section, in order to obtain the distance ratio value (%) in the vicinity of the single fiber cross section k and the PU resin area ratio (%) in the cross section, 10 SEM images are taken substantially evenly in the CD direction orthogonal to the MD direction. Further, in order to obtain the surface PU resin area ratio (%) in each sampling region, the first outer surface of the fiber layer (A) at 10 locations substantially uniformly in the CD direction is coated with 1 nm of osmium atoms. And the SEM image of the first outer surface thereof is taken. Further, in order to obtain the spatial size in each sampling region, three-dimensional images are taken by X-ray CT at 10 points substantially evenly in the CD direction. That is, 100 images are prepared for each of the single fiber cross-section k-nearest neighbor ratio value (%), the cross-section PU resin area ratio (%), and the space size. In this case, the average value and standard deviation of each value are for 100 images.
When the artificial leather is raised, it can be determined that the raising direction is the MD direction. When the artificial leather is not brushed and the MD direction is unknown, the sample may be cut out in any one direction and in the direction orthogonal to the direction.

(2) Single fiber cross section k-nearest neighbor distance ratio value (%)
As shown in FIG. 5, the k-nearest neighbor method is a method in which k single fiber cross sections close to any one single fiber cross section are taken up and the radius closest to the kth in the Euclidean distance is set as the determination boundary.
In the present embodiment, in one SEM image, a range of about 250 μm × about 186 μm is photographed with 640 × 480 pixels with wrapping under the image (in this case, 1 pixel corresponds to about 0.40 μm × about 0.40 μm). , It is determined whether or not a single fiber cross section close to k = 9 exists within a distance of a radius of 20 μm from the substantially center of any one single fiber cross section. For all the single fiber cross sections in one SEM image, the presence or absence is determined, and the single fiber cross section k = 9 neighborhood distance ratio value (%) is calculated by the following formula:
Single fiber cross section (k = 9) Near distance ratio value (%) = {(Number of single fiber cross sections in which k = 9th closest single fiber cross section exists within a radius of 20 μm from the approximate center of the single fiber cross section. ) / (Total number of single fiber cross sections in one SEM image)} x 100.
The single fiber cross section k = 9 neighborhood distance ratio value (%) is an average value of each value calculated from 100 SEM images. When the sample has a scrim, the deepest portion (that is, the portion on the scrim side) of the fiber layer (A) on the cut surface of the conductively treated sample is set as an observation region, and the fibers constituting the scrim are observed. Observe with a scanning electron microscope (SEM, "JSM-5610" manufactured by JEOL Ltd.) as a non-target object. When the sample does not have a scrim, the central portion in the thickness direction of the artificial leather on the cut surface of the conductively treated sample is set as the center point of the observation region, and the sample is observed by the SEM.
As shown in FIG. 4, the single fiber cross section in the SEM image can be identified by human marking. The specific procedure is as follows:
[Procedure 1]
In the SEM image (gray), after adding a red (R) circle to the fiber cross section, the coordinates of the fiber cross section are calculated.
<Detailed method>
(I) Read an image using OpenCV (cv2 module for Python).
(Ii) Pixels having RGB R of 220 or more and G and B of 100 or less are extracted.
(Iii) For noise processing, expansion processing (cv2.dilate with iteration = 2) and contraction processing (cv2.erode with iteration = 2) of the detected round points are performed.
(Iv) The noise-processed image is cv2. It is processed by component With Stats, and the coordinates of the center of gravity of the detected round point, which is the third result among the four results obtained, are obtained.
(V) Let the coordinates of the center of gravity be the fiber cross-sectional position.
(Vi) Further, the distance between specific positions on the coordinates is calculated. When the coordinates of the fiber cross section A and the fiber cross section B are (Ax, Ay) and (Bx, By), the two Euclidean distances R are R = √ ((Ax-Bx) ² + (Ay-By) ² ). It is calculated by.
[Procedure 2]
For all fiber cross sections, the Euclidean distance (k-nearest neighbor distance: matrix distance) to the k-th closest fiber cross section is calculated.
<Detailed method>
(I) Calculate the distance between the fiber cross section A and the coordinates of the other cross sections.
(Ii) Arrange the calculated distances in ascending order.
(Iii) Let the k-th arranged distance be the k-nearest neighbor distance.
[Procedure 3]
The number of cross sections whose k-nearest neighbor distance is R or less is divided by the total number of fiber cross sections to obtain the k-nearest neighbor distance ratio value in the SEM image.
When the number of SEM images is large, an image including teacher data (correct label) with red (R) circles on the fiber cross section is used as training data, and all are composed of convolutional layers. Network FCN (Fully Convolutional Networks) method (Jonathan Long, Evan Shelhamer, and Trevor Darrel (2015): Fully Convolutional Networks for Semantic Segmentation. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR) by semantic segmentation using pixels By machine learning (deep learning) that classifies by level, the position of the fiber cross section may be specified instead of human marking.

(3) Cross-section PU resin area ratio (%) and standard deviation / pretreatment After cutting the sample in the thickness direction cross-section into 1 cm x 0.5 cm (horizontal (x) x vertical (y)), the internal space of the sample. Was embedded in an epoxy resin (main agent: "Quetol 812" manufactured by Nissin EM Co., Ltd., curing agent: "MNA" manufactured by Nissin EM Co., Ltd., accelerator: "DMP-30" manufactured by Nissin EM Co., Ltd.). The obtained resin-embedded sample is cut in parallel with the thickness direction with a microtome to obtain a smooth cut surface. Then, it is allowed to stand in the saturated vapor of ruthenium tetroxide for 4 hours, and the PU resin adhering to the sample is electron-stained with ruthenium. Next, the osmium atom is coated with 1 nm to conduct a conductive treatment.
-When the observation sample has a scrim, the deepest part (that is, the part on the scrim side) of the fiber layer (A) on the cut surface of the conductively treated sample is set as the observation region, and the fibers constituting the scrim are observed. Observe with a scanning electron microscope (SEM, "SU8220" manufactured by Hitachi High-Technologies Corporation) as a non-target. When the sample does not have a scrim, the central portion in the thickness direction of the artificial leather on the cut surface of the conductively treated sample is set as the center point of the observation region, and the sample is observed by the SEM. The observation conditions are as follows.
Acceleration voltage: 10kV
Detector: YAG-BSE (annular scintillator type reflected electron)
Imaging magnification: 500 times Observation field of view: Approximately 230 μm x Approximately 173 μm
-Image analysis For the obtained SEM reflected electron image, use the image analysis software "ImageJ (version: 1.51j8) National Institutes of Health) to binarize the image by the following method, and determine the average size of the PU resin. Ask.
(I) Filter the SEM image. The processing conditions are as follows:
Hand path filtering Filter large structures down to 40 pixels, Filter small structures up to 3 pixels, Suppress stipes None, Tolerance of direction 5%, Autoscale after filtering, Saturate image when autoscaling, and as median filtering, radius: 4 or 1 filter process.
(Ii) Binarization is performed by the Max Entry method, and the black portion in the binarized SEM image is used as PU resin.
(Iii) From the obtained binarized image, the area ratio of the PU resin to each section is obtained.
As shown in FIG. 6, the obtained binarized image (1280 × 960pixel, 1280 × 896pixel excluding the band under the image) is divided into 32 × 32pixels (in this case, 1120 divisions), and ImageJ's Analyze Plastic Using the function (condition: Size = 0-infinity, Circularity = 0.00-1.00), the value obtained by dividing the total area of each PU resin distributed in each section by the area of each section is used. The cross-sectional PU resin area ratio (%) of the section is used. The number of pixels on the x and y axes of the target image is read, the partition size is specified by the pixel size, the number of divisions on the x and y axes is obtained, and the PU resin area% in each division area is calculated.
The area ratio of PU resin calculated from one SEM image is the average of the area ratio of PU resin for all sections of one SEM image, and the standard deviation is calculated by the formula shown in FIG. Will be done.
The cross-sectional PU resin area ratio (%) and standard deviation are average values of the PU resin area ratio and standard deviation calculated from one SEM image for 100 sheets. That is, as shown in FIG. 6, first, the standard deviation is calculated for all the sections divided into sections for one SEM image, and the average of the standard deviations calculated from each of the 100 SEM images is used as the standard deviation.

(4) Average diameter (μm) of the single fibers constituting the fiber layer (A)
For the average diameter of the fibers constituting the fiber layer (A), a scanning electron microscope (SEM, "JSM-5610" manufactured by JEOL Ltd.) was used for the cross section of the fiber layer (A) constituting the artificial leather in the thickness direction. 10 SEM images were taken at a magnification of 1500, 100 fibers forming the first outer surface of the artificial leather were randomly selected, the diameter of the cross section of the single fiber was measured, and the arithmetic mean of the 100 measured values was measured. Obtain as a value.
When the observed shape of the cross section of the single fiber is not circular, the distance between the outer circumferences on a straight line orthogonal to the midpoint of the longest diameter of the single fiber cross section is defined as the fiber diameter.
FIG. 2 is a conceptual diagram illustrating how to obtain the fiber diameter. For example, when the cross section A of the fiber is elliptical as shown in FIG. 2, the distance c between the outer circumferences on the straight line b orthogonal to the midpoint p of the longest diameter a of the cross section A in the observation image is defined as the fiber diameter.

(5) Space size (μm)
A three-dimensional image of the fiber layer (A) is taken by X-ray CT, and the average value in the thickness direction of the diameter (μm) of the largest sphere that enters the space excluding the fibers constituting the fiber layer (A) and the PU resin mass. Is the space size, and is calculated by the following procedure.
(I) Rotate the image so that the xz axis is in-plane and the y-axis is in the thickness direction on the screen, and the image is trimmed into a rectangular parallelepiped.
(Ii) The median filter is carried out under the condition of a radius of 2 pix.
(Iii) The region is divided by applying the Otsu method. The brightness value of the pixel is set to 0 for air, 255 for non-woven fibers, and 255 for urethane resin.
(Iv) The image processing method segmentation is performed on the pixels having the brightness value 255 (fiber, PU resin), and the structure in which the number of pixels (pix) of the connected portion having the brightness value 255 is 10,000 or less is removed as noise. To do.
(V) For a brightness value of 0 (air), the tickness method of image analysis is performed to obtain the spatial size. Every pixel in the 3D image has a spatial size value.
(Vi) A two-dimensional original image of the xz plane is cut out in the y-axis (thickness direction) with a thickness of 1 pix, and the average and standard deviation of the space size on that plane are obtained.
(Vii) The above (vi) is performed for all y to obtain a profile in the thickness direction.
The spatial size (μm) and standard deviation are average values of each value calculated from three-dimensional images obtained by 100 X-ray CTs. When the sample has a scrim, the deepest part of the fiber layer (A) (that is, the part on the scrim side) is set as the observation area, and the fibers constituting the scrim are excluded from the observation target. Take a picture with "High resolution 3DX fiber microscope" manufactured by Rigaku Co., Ltd. When the sample does not have a scrim, the central portion of the thickness in the cross section in the thickness direction is set as the center point of the observation region, and an image is taken.

(6) Calculation of texture (rigidity / softness value) Each sample was cut into a square of 20 cm × 20 cm and used as a measurement sample. The measurement sample was placed on a horizontal plane, and the vertices A and C facing each other on the diagonal line were overlapped with the vertices of the squares being A, B, C, and D. Vertex A was placed on a horizontal plane and vertex C was superimposed on vertex A. Next, the apex C is gradually moved away from the apex A along the diagonal line AC in a state of being in contact with the measurement sample, and the point where the apex C is separated from the measurement sample surface is defined as the point E, and the points E and the apex C are The distance was set to a flexible value of 1. The flexibility value 2 was measured by substituting the apex A with the apex B and the apex C with the apex D in the same procedure as described above. The arithmetic mean value of the flexibility value 1 and the flexibility value 2 was taken as the texture (rigid / soft value) of the sample. When the artificial leather is a single layer, the average value for 10 samples is taken as the texture (rigid and soft value). When the artificial leather has a two-layer structure or a three-layer structure, five samples measured with the fiber layer (A) constituting the artificial leather on the upper surface and five samples measured with the fiber layer (A) on the lower surface. The average value for the sample is the texture (rigid and soft value).

(7) Denseness (dispersity of fiber bundles)
The sample was evaluated on a 7-point scale by visual and sensory evaluation, with 10 adult males and 10 adult females in good health, for a total of 20 evaluators, and the most frequent evaluation was defined as a sense of detail. The feeling of fineness (dispersity of fiber bundles) is good (passed) in the 4.0 to 7.0 grade.
Grade 7: The brushing is very fine and the appearance is very good.
Grade 6: Evaluation between grades 7 and 5.
Grade 5: The brushing is fine and the appearance is good.
Grade 4: Evaluation between grade 5 and grade 3.
Grade 3: There is uniform brushing on the whole, and the appearance is like leather.
2nd grade: Evaluation between 3rd grade and 1st grade.
Grade 1: Brushed is mottled and the appearance is poor.
The average value for 10 samples is used as the grade of precision.

(8) Adhesion rate of PU resin to fiber sheet The adhesion rate of PU resin to fiber sheet was measured by the following method.
Let A (g) be the mass of the fiber sheet before impregnation with the PU resin. The fiber sheet is impregnated with the PU resin dispersion, then dried by heating at 130 ° C. using a pin tenter dryer, then softened while immersed in hot water heated to 90 ° C., and then dried to obtain the PU resin. A filled fiber sheet (hereinafter, also referred to as “resin-filled fiber sheet”) is obtained. Let the mass of the resin-filled fiber sheet be B (g). The adhesion rate (C) of the PU resin is calculated by the following formula.
C = (BA) / A × 100 (wt%)

(9) Average primary particle size of PU resin in PU resin dispersion Measure with a laser type diffraction type particle size distribution measuring device (“LA-920” manufactured by HORIBA, Ltd.) according to the device measurement manual, and measure the median diameter. The average primary particle size was used.

(10) Degree of saponification of PVA resin fine particles contained in PU resin dispersion The measurement was performed according to JIS K 6726 (1994) 3.5.

(11) Degree of polymerization of PVA resin fine particles contained in PU resin dispersion The measurement was performed according to JIS K 6726 (1994) 3.7.

(12) Average particle size (size) (μm) of PVA resin fine particles contained in the PU resin dispersion.
"NL-05" manufactured by Mitsubishi Chemical Corporation can be used as the fine particles, and the miniaturization of the hot water-soluble resin fine particles conforms to the method described in JP-A-7-82384.

(13) Disturbance of the water flow discharged from the nozzle in the water flow dispersion treatment The disturbance of the water flow discharged from the nozzle in the water flow dispersion treatment was measured by the following method.
The water flow discharged from the nozzle is photographed with a single-lens camera (“D600” manufactured by Nikon Corporation) equipped with a telecentric lens (“S5LPJ007 / 212” manufactured by Mill Optics GmbH & Co. KG) to obtain image data. The image data is taken into a PC, a water flow in the range of 25 mm to 35 mm is cut out from the discharge port of the nozzle hole, and the water flow diameter is measured for each 1 pixel row (about 6 μm) in the width direction of the water flow. From all the measured data, the average diameter W and standard deviation σ of the water flow in the range of 25 mm to 35 mm from the discharge port of the nozzle hole are calculated, and the disturbance is calculated by the following formula.
Disturbance (%) = σ (mm) / W (mm) x 100
The disturbance is the average value of the values obtained from the five image data.

[Example 1]
As the sea component, polyethylene terephthalate obtained by copolymerizing 8 mol% of sodium 5-sulfoisophthalate was used, and as the island component, polyethylene terephthalate was used. The sea component was 20% by mass and the island component was 80% by mass. Sea-island type composite fibers having 16 islands / 1f and an average fiber diameter of 18 μm were obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber web was formed through a curd and a cross wrapper, and a fiber sheet was obtained by needle punching. The obtained fiber sheet was immersed in hot water at 95 ° C. to shrink, and dried at 100 ° C. for 5 minutes using the pin tenter dryer to obtain a single-layer fiber sheet having ^{a basis weight of 600 g / m 2.}
The obtained fiber sheet was immersed in a sodium hydroxide aqueous solution having a concentration of 10 g / L heated to a temperature of 95 ° C. and treated for 25 minutes to perform a desealing treatment for removing the sea component of the sea-island type composite fiber. The average diameter of the single fibers of the fibers constituting the fiber sheet after desealing was 4 μm.
Next, a high-speed water stream using a three-row linear flow injection nozzle with a nozzle hole spacing of 0.25 mm, disturbance of 17%, and a hole diameter of 0.10 mm was injected multiple times at a pressure of 4 MPa from the upper layer side and 3 MPa from the lower layer side, and the fibers were injected. It promoted the monofilament of the fibers constituting the bundle.
Next, the amount (solid content concentration: 35% by mass) in the impregnating liquid (solid content concentration: 35% by mass) of the polyether-based aqueous dispersion type PU dispersion "AE-12" (manufactured by Nikka Kagaku Co., Ltd.) having an average primary particle size of 0.3 μm was added. 9.0% (as a mass% of solid content), 3.0% by weight (as a mass% of solid content) of anhydrous glass as an impregnation aid, and PVA resin fine particles "NL-" having an average particle size of 3 μm. The fiber sheet is impregnated with an impregnating solution containing "05" (manufactured by Mitsubishi Chemical Co., Ltd.), then moist and heat-solidified at 100 ° C. for 5 minutes, and hot air is used at 130 ° C. to 150 ° C. for 2 to 6 minutes using a pin tenter dryer. It was dried.
Then, it was immersed in hot water heated to 95 ° C. to extract and remove the impregnated anhydrous sodium sulfate and PVA resin fine particles to obtain a sheet-like material filled with an aqueous dispersion type PU resin. The ratio of the water-dispersed PU resin to the total fiber mass of this sheet-like material was 30% by mass.
Then, using a half-cutting machine having an endless band knife, the sheet-like material is half-cut perpendicular to the thickness direction, and the uncut surface is brushed with # 400 emeri paper, and then the dye concentration is 5 It was dyed with a 0.0% owf blue disperse dye (“BlueFBL” manufactured by Sumitomo Chemical Co., Ltd.) at 130 ° C. for 15 minutes using a liquid flow dyeing machine, and was subjected to reduction washing. Then, it was dried at 100 ° C. for 5 minutes using a pin tenter dryer to obtain a single-layer artificial leather.

[Example 2]
Artificial leather was obtained in the same manner as in Example 1 except that the disturbance in the water flow dispersion treatment was changed to 13%.

[Example 3]
Artificial leather was obtained in the same manner as in Example 1 except that the disturbance in the water flow dispersion treatment was changed to 11%.

[Example 4]
Artificial leather was obtained in the same manner as in Example 1 except that the disturbance in the water flow dispersion treatment was changed to 7%.

[Example 5]
Artificial leather was obtained in the same manner as in Example 1 except that the pressure on the upper layer side of the high-speed water flow was changed to 5.5 MPa.

[Example 6]
Artificial leather was obtained in the same manner as in Example 1 except that the pressure on the upper layer side of the high-speed water flow was changed to 12.0 MPa.

[Example 7]
Artificial leather was obtained in the same manner as in Example 1 except that the nozzle hole diameter in the water flow dispersion treatment was changed to 0.15 mm.

[Example 8]
Artificial leather was obtained in the same manner as in Example 1 except that the nozzle hole diameter in the water flow dispersion treatment was changed to 0.22 mm.

[Example 9]
Artificial leather was obtained in the same manner as in Example 1 except that the nozzle hole spacing in the water flow dispersion treatment was changed to 0.50 mm.

[Example 10]
Artificial leather was obtained in the same manner as in Example 1 except that the nozzle hole spacing in the water flow dispersion treatment was changed to 0.50 mm and the nozzle hole row was changed to one row.

[Example 11]
Artificial leather was obtained in the same manner as in Example 1 except that the nozzle hole spacing in the water flow dispersion treatment was changed to 0.90 mm and the nozzle hole row was changed to one row.

[Example 12]
An artificial leather was obtained in the same manner as in Example 1 except that the average particle size of the PVA resin fine particles was changed to 1.5 μm.

[Example 13]
An artificial leather was obtained in the same manner as in Example 1 except that the average particle size of the PVA resin fine particles was changed to 7.0 μm.

[Example 14]
Artificial leather was obtained in the same manner as in Example 1 except that the ratio of PU resin to the fiber sheet was 24% by mass.

[Example 15]
Artificial leather was obtained in the same manner as in Example 1 except that the ratio of PU resin to the fiber sheet was 43% by mass.

[Comparative Example 1]
Artificial leather was obtained in the same manner as in Example 1 except that the water flow dispersion treatment was not carried out.

[Comparative Example 2]
Artificial leather was obtained in the same manner as in Example 1 except that PVA resin fine particles were not added to the PU resin impregnated liquid.

[Comparative Example 3]
An artificial leather was obtained in the same manner as in Example 1 except that the average particle size of the PVA resin fine particles was changed to 0.5 μm.

[Comparative Example 4]
An artificial leather was obtained in the same manner as in Example 1 except that the average particle size of the PVA resin fine particles was changed to 11 μm.

[Comparative Example 5]
Artificial leather was obtained in the same manner as in Example 1 except that the ratio of PU resin to the fiber sheet was 14% by mass.

[Comparative Example 6]
Artificial leather was obtained in the same manner as in Example 1 except that the ratio of PU resin to the fiber sheet was 53% by mass.

The results of Examples 1 to 15 and Comparative Examples 1 to 6 are shown in Table 1 below.

From these results, in each example, the k-near distance ratio value (k = 9, radius r = 20 μm) between the cross sections of the single fibers constituting the fiber layer (A) was 10% or more and 80% or less. Moreover, the cross-sectional PU resin area ratio in the cross section in the thickness direction is 10% or more and 30% or less, and the standard deviation of the cross-sectional PU resin area ratio is 25% or less, and the PU resin and the single fiber are distributed in a specific structure. It can be seen that the artificial leather that has both the texture (rigid and soft value), the dense feeling, and the moist feeling was obtained.

Since the artificial leather according to the present invention is excellent in texture (rigidity and softness), denseness, and moistness, it is a clothing product such as a skin material or an interior material for seats for interiors, automobiles, aircrafts, railroad vehicles, etc. Etc., it can be suitably used. Specifically, the artificial leather of the present invention is an interior material or shirt having a very elegant appearance as a skin material for seats, ceilings, interiors, etc. in the vehicle interior of furniture, chairs, wall materials, automobiles, trains, aircraft, etc. , Jackets, casual shoes, sports shoes, men's shoes, women's shoes, etc., uppers, trims, bags, belts, wallets, etc., clothing materials used for some of them, wiping cloth, polishing cloth, CD curtains, etc. Can be suitably used as an industrial material of.

1 Fiber sheet 11 Scrim (optional)
12 Fiber layer (A)
13 Fiber layer (B)
A Cross section of the fiber when the cross section is elliptical a Longest diameter of cross section A b Straight line passing through the midpoint p of the longest diameter a and orthogonal to the longest diameter a c Distance between outer circumferences on the straight line b p Midpoint of the longest diameter a MD Machine direction CD width (horizontal) direction t Artificial leather thickness

Claims

An artificial leather containing a fiber sheet and a polyurethane resin, wherein the fiber sheet contains at least a fiber layer (A) constituting the first outer surface of the artificial leather, and the artificial leather has a cross section in the thickness direction. The k proximity distance ratio value (k = 9, radius r = 20 μm) between the single fiber cross sections constituting the fiber layer (A) is 10% or more and 80% or less, and the thickness of the fiber layer (A). The cross-sectional polyurethane resin area ratio in the directional cross section is 10% or more and 30% or less, and the standard deviation of the cross-sectional polyurethane resin area ratio in the thickness direction cross section of the fiber layer (A) is 25% or less. The artificial leather.
In a three-dimensional image of the fiber layer (A) by X-ray CT, the fiber layer having a space size that is the diameter of the maximum sphere that enters the space excluding the fibers constituting the fiber layer (A) and the polyurethane resin. The artificial leather according to claim 1, wherein the average value (average space size) in the thickness direction of (A) is 5 μm or more and 35 μm or less.
The fiber sheet has a structure of two or more layers composed of a fiber layer (A) constituting the first outer surface and a scrim and / or a fiber layer (B) in contact with the fiber layer (A). , The artificial leather according to claim 1 or 2.
The artificial leather according to any one of claims 1 to 3, wherein the average diameter of the single fibers constituting the fiber layer (A) is 1.0 μm or more and 8.0 μm or less.
The artificial leather according to any one of claims 1 to 4, wherein the polyurethane resin is a water-dispersible polyurethane resin.
The artificial leather according to any one of claims 1 to 5, wherein the adhesion rate of the polyurethane resin to the fiber sheet is 15% by mass or more and 50% by mass or less.
The artificial leather according to any one of claims 1 to 6, which has a hardness of 28 cm or less.
The artificial leather according to any one of claims 1 to 7, wherein the fiber sheet is made of polyester fiber.
The artificial leather according to any one of claims 1 to 8, which has a feeling of precision of 4.0 grade or higher.
The following steps:
A step of forming a fiber web from Kaijima short fibers and then desealing the fiber sheet obtained by needle punching to obtain a fiber sheet in which the island component single fibers are exposed; and water flow dispersion on the obtained fiber sheet. The process of applying treatment to obtain a fiber sheet in which single fibers are dispersed;
The method for producing artificial leather according to any one of claims 1 to 9, which comprises.
The following steps:
The fiber sheet in which the single fibers are dispersed is impregnated with a water-dispersed polyurethane resin dispersion liquid containing hot water-soluble resin fine particles, and then the polyurethane resin is fixed by heating to form a sheet filled with the polyurethane resin. A step of obtaining a product; and a step of removing the hot water-soluble resin fine particles from the obtained sheet-like material using hot water;
The manufacturing method according to claim 10, further comprising.
The production method according to claim 10 or 11, wherein the hot water-soluble resin fine particles are polyvinyl alcohol resins.
Any of claims 10 to 12, wherein the water flow dispersion treatment is carried out using a plurality of nozzles having a nozzle hole spacing of 1.0 mm or less and a nozzle hole diameter of 0.05 mm or more and 0.30 mm or less. The manufacturing method according to item 1.
The manufacturing method according to any one of claims 10 to 13, wherein the water flow dispersion treatment is carried out using a plurality of nozzles that discharge a water flow having a disturbance of 10% or more.
The production method according to any one of claims 11 to 14, wherein the solid content concentration of the aqueous dispersion type polyurethane resin dispersion liquid is 10% by weight or more and 35% by weight or less.
The production method according to any one of claims 11 to 15, wherein the content of the hot water-soluble resin fine particles in the water-dispersible polyurethane resin dispersion is 1% by weight or more and 20% by weight or less.