EP4053330A1 - Cuir artificiel et son procédé de production - Google Patents

Cuir artificiel et son procédé de production Download PDF

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Publication number
EP4053330A1
EP4053330A1 EP20880857.6A EP20880857A EP4053330A1 EP 4053330 A1 EP4053330 A1 EP 4053330A1 EP 20880857 A EP20880857 A EP 20880857A EP 4053330 A1 EP4053330 A1 EP 4053330A1
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EP
European Patent Office
Prior art keywords
resin
fiber
artificial leather
fibers
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20880857.6A
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German (de)
English (en)
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EP4053330A4 (fr
Inventor
Daisuke Hironaka
Yoshiyuki Tadokoro
Keiichiro SAKATA
Masaya KAWASAKI
Aguru YAMAMOTO
Hisaki Ikebata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
Original Assignee
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Application filed by Asahi Kasei Corp, Asahi Chemical Industry Co Ltd filed Critical Asahi Kasei Corp
Publication of EP4053330A1 publication Critical patent/EP4053330A1/fr
Publication of EP4053330A4 publication Critical patent/EP4053330A4/fr
Pending legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
    • D06N3/14—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
    • D06N3/0004—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using ultra-fine two-component fibres, e.g. island/sea, or ultra-fine one component fibres (< 1 denier)
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
    • D06N3/0011—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using non-woven fabrics
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
    • D06N3/0013—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using multilayer webs
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
    • D06N3/0015—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using fibres of specified chemical or physical nature, e.g. natural silk
    • D06N3/0036—Polyester fibres
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0043—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by their foraminous structure; Characteristics of the foamed layer or of cellular layers
    • D06N3/0052—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by their foraminous structure; Characteristics of the foamed layer or of cellular layers obtained by leaching out of a compound, e.g. water soluble salts, fibres or fillers; obtained by freezing or sublimation; obtained by eliminating drops of sublimable fluid
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0056—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the compounding ingredients of the macro-molecular coating
    • D06N3/0068—Polymeric granules, particles or powder, e.g. core-shell particles, microcapsules
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/007—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by mechanical or physical treatments
    • D06N3/0075—Napping, teasing, raising or abrading of the resin coating
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2203/00—Macromolecular materials of the coating layers
    • D06N2203/06—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06N2203/068—Polyurethanes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2205/00—Condition, form or state of the materials
    • D06N2205/02—Dispersion
    • D06N2205/023—Emulsion, aqueous dispersion, latex
    • D—TEXTILES; PAPER
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    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2205/00—Condition, form or state of the materials
    • D06N2205/24—Coagulated materials
    • D06N2205/243—Coagulated materials by heating, steam
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2207/00—Treatments by energy or chemical effects
    • D06N2207/06—Treatments by energy or chemical effects using liquids, e.g. water
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2209/00—Properties of the materials
    • D06N2209/16—Properties of the materials having other properties
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2209/00—Properties of the materials
    • D06N2209/16—Properties of the materials having other properties
    • D06N2209/1642—Hardnes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2211/00—Specially adapted uses
    • D06N2211/12—Decorative or sun protection articles
    • D06N2211/26—Vehicles, transportation
    • D06N2211/263—Cars
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2211/00—Specially adapted uses
    • D06N2211/12—Decorative or sun protection articles
    • D06N2211/26—Vehicles, transportation
    • D06N2211/265—Trains
    • D—TEXTILES; PAPER
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    • D06N2211/00—Specially adapted uses
    • D06N2211/12—Decorative or sun protection articles
    • D06N2211/26—Vehicles, transportation
    • D06N2211/267—Aircraft
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
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    • D06N2211/00—Specially adapted uses
    • D06N2211/12—Decorative or sun protection articles
    • D06N2211/28—Artificial leather

Definitions

  • the present invention provides artificial leather that has texture (stiffness), a luxuriant feel (dispersibility of fiber bundles) and a slick feel (resin masses of appropriate size), as well as a method for producing it.
  • Artificial leather that has a fiber sheet such as a nonwoven fabric (fibrous base material) and a polyurethane (PU) resin as the major materials exhibits excellent properties that are difficult to achieve with natural leather, including easy care, functionality and homogeneity, and it is therefore suitable for use in clothing, shoes and bags, as well as for sheet covering materials and interior finishing materials for interiors, automobiles, aircraft and railway vehicles, or decorative materials such as ribbons or patch bases.
  • a fiber sheet such as a nonwoven fabric (fibrous base material) and a polyurethane (PU) resin
  • PU polyurethane
  • One commonly used method for producing such artificial leather in the prior art is a method of impregnating a fiber sheet with an organic solvent solution of a PU resin, and then immersing it in a non-solvent for the PU resin (such as water or an organic solvent), for wet coagulation of the PU resin.
  • PTL 1 for example, uses an organic solvent-based PU resin with N,N-dimethylformamide as the organic solvent for the PU resin.
  • common organic solvents are very harmful for the human body and the environment, there is a strong demand for methods of producing artificial leather that do not use organic solvents.
  • PTL 2 examines a method of using a water-dispersed PU resin dispersion with PU resin dispersed in water, as a substitute for conventional organic solvent-based PU resins, but sheets obtained by impregnating fiber sheets with water-dispersed PU resin dispersions to coagulate the PU resins tend to exhibit a hard texture.
  • the coagulating system of an organic solvent-based PU resin dispersion is a "wet coagulation system" wherein an organic solvent dissolving the PU molecules is solvent-exchanged with water to precipitate out the PU molecules, and in the case of a PU film it forms a porous film of low density.
  • a water-dispersed PU resin is a "dry heat coagulating system" wherein the hydrated state of the PU molecules dispersed in water is disintegrated primarily by heating, and the PU molecules are caused to aggregate together causing coagulation, resulting in a non-porous film with a highly dense PU film structure.
  • Adhesion between the fibers and PU resin is therefore dense and the intertwined portions of the fibers are firmly held fast, resulting in a hard texture.
  • a method for producing a sheet in which a PU resin dispersion comprising a water-dispersed PU resin, a foaming agent and an anionic surfactant and/or amphoteric surfactant is added to a fiber sheet it is possible to create a porous structure of the PU resin inside the sheet regardless of the type of foaming agent or PU, and it is possible to produce a sheet having uniform nap lengths similar to artificial leather types that use organic solvent-based PU resins, while also having a delicate surface quality with an excellent luxuriant fiber feel and a satisfactory flexible texture
  • a sheet obtained by the method described in PTL 2 has large voids between the ultrafine fiber bundles and the PU resin (the PU resin has a porous structure), so that firm bonding of the PU resin to the ultrafine fiber bundles is inhibited resulting in a partially flexible texture, but the cross-sectional area ratio of the PU resin is still relatively high and the dispersibility of the PU resin is not sufficient, while the dispersibility of the single fibers is not considered in this publication.
  • PTL 3 discloses a sheet having a uniform feel comparable to artificial leather that uses an organic solvent-based PU resin, and a delicate surface quality and satisfactory texture, as well as a method for producing it, with the goal of providing a sheet having a PU resin porous structure by the use of a water-dispersed PU resin and having wrinkle recoverability and flexibility very similar to artificial leather that uses an organic solvent-based PU resin, as well as a method for producing the same, where the solution means disclosed is a sheet that is composed of a fiber sheet comprising ultrafine fibers and/or ultrafine fiber bundles, with a elastomer having hydrophilic groups (such as a water-dispersed PU resin) added as a binder, and wherein in a cross-section of the sheet cut in the thickness direction, the proportion of independent sections with a cross-sectional area of 50 ⁇ m 2 or greater in the elastomer observed within the cut surface is 0.1% to 5.0% of the cross-sectional area of the artificial leather in the observation field, the method
  • the thickener used is guar gum which has high thixotropy at low concentration, that the thixotropic dispersion results in lower viscosity when force is applied by stirring or the like, allowing the dispersion to be uniformly impregnated into the fiber sheet, and that the viscosity is restored if the dispersion is left to stand after application of force, such that the dispersion impregnated into the fiber sheet is less likely to be shed from the fiber sheet.
  • an artificial leather base material comprising a three-dimensional intertwined nonwoven fabric and a elastomer, for the purpose of providing an artificial leather base material exhibiting excellent mechanical properties, flexibility, texture and lightweight properties, wherein the artificial leather base material satisfies the following condition (1): the elastomer on the surfaces of the fibers forming the three-dimensional intertwined nonwoven fabric is discontinuous; condition (2): the average area of inter-void inscribed circles excluding inter-void inscribed circle areas of less than 350 ⁇ m 2 in parallel cross-sections in the thickness direction of the artificial leather base material is 1250 ⁇ m 2 or lower; and condition (3): the number of inter-void inscribed circles with inter-void inscribed circle areas of 350 to 3000 ⁇ m 2 in parallel cross-sections in the thickness direction of the artificial leather base material is at least 85% with respect to the total number of inter-void inscribed circles.
  • This type of artificial leather base material can be obtained by a process of impregnating the three-dimensional intertwined nonwoven fabric with a water-dispersed PU resin dispersion having polyvinyl alcohol (PVA) resin added, and coagulating it to form a elastomer.
  • PVA polyvinyl alcohol
  • the elastomer since the elastomer has a consistent non-contact structure with the fibers and is discontinuous on the fiber surfaces, with the PU resin evenly dispersed in the interior, the voids are evenly distributed between the fibers to provide an artificial leather base material exhibiting excellent mechanical properties, flexibility and lightweightness suitable for use in sports shoes, for example, and having an excellent textural feel.
  • the artificial leather base material obtained by the method described in PTL 4 has improved dispersibility of the water-dispersed PU resin and exhibits flexibility and light weight, the dispersibility of the single fibers is less than satisfactory and it therefore lacks a luxuriant feel.
  • the artificial leather base material described in PTL 4 is also primarily used for "smooth" artificial leather that has a grain side appearance.
  • PTL 5 proposes a sheet comprising a elastomer inside a fiber sheet that contains ultrafine fibers with average single fiber diameters of 0.3 to 7 ⁇ m, and having naps on the surface, with the goal of providing a leather-like sheet with a satisfactory surface touch and excellent coloring properties and appearance quality for extended periods, and a method for producing it, wherein in terms of naps present within 0.2 ⁇ m from the sheet surface in the thickness direction, for the minimum interfiber distances between each fiber among 100 randomly extracted fibers and its nearest adjacent nap, the average value for the 100 fibers is 10 to 30 ⁇ m, and when 20 surrounding naps are selected in order of closer distance from each fiber among 100 randomly extracted fibers, the standard deviation for their interfiber distances for the 100 fibers is 10 or lower.
  • the sheet is obtained by a process comprising the following step 1: removal of the sea-component from the fiber sheet containing sea-island fibers to obtain ultrafine fibers; step 2: alkali reduction treatment of the ultrafine fibers of the fiber sheet containing ultrafine fibers; step 3: addition of a elastomer to the obtained fiber sheet after steps 1 and 2; and step 4: slicing the sheet in half horizontally after step 3, and buffing treatment of at least one side of the sliced sheet.
  • PTL 5 states that it is preferred to uniformly disperse the ultrafine fibers after alkali reduction treatment of the ultrafine fibers, and that the treatment for uniform dispersion of the ultrafine fibers is a method of showering the fiber sheet with water after alkali reduction treatment, a method of immersing the fiber sheet in water and dispersing the fibers while contacting them with a water stream in a Vibrowasher or the like, or a method of dispersing the fibers while contacting them with a water stream using a water jet punch, that the treatment for uniform dispersion of the ultrafine fibers causes the ultrafine fibers to be homogeneously distributed, and that by using fibers with average single fiber diameters of 0.3 to 7 ⁇ m and satisfactory coloring properties it is possible to obtain a sheet that has the naps in a well-dispersed state for long periods without temporary surface-touch modification by chemical agents, and exhibits a satisfactory surface touch property (a non-rough feel), uniform naps, delicate appearance quality and excellent coloring properties.
  • the problem to be solved by the invention is that of providing artificial leather with minimal harm to the human body and environment, and having a level of quality that can satisfactory all of the properties of texture (stiffness), luxuriant feel (fiber bundle dispersibility) and slick feel (suitable sizes of the PU resin masses), as well as a method for producing it.
  • the present inventors have found, unexpectedly, that the problem can be solved by the artificial leather having the following features.
  • the present invention provides the following.
  • the artificial leather of the invention has excellent texture (stiffness), luxuriant feel (fiber bundle dispersibility) and slick feel (suitable sizes of the polyurethane resin masses), and can therefore be satisfactorily used as a sheet covering material or interior finishing material for interiors, automobiles, aircraft or railway vehicles, or in a clothing product.
  • artificial leather is that defined according to the Household Goods Quality Labeling Law as “leather comprising a special nonwoven fabric (mainly a fiber layer having a random three-dimensional spatial structure, impregnated with a PU resin or a elastomer of similar flexibility) as the base material".
  • leaf material mainly a fiber layer having a random three-dimensional spatial structure, impregnated with a PU resin or a elastomer of similar flexibility
  • a suede-like outer appearance can be formed by buffing treatment (raising treatment) of the outer surface of the fiber layer (A) (the side that is to be the first outer surface of the artificial leather) using sandpaper or the like.
  • the first outer surface of the artificial leather is the surface that is externally exposed when the artificial leather is used (the surface that contacts with the human body, in the case of a chair, for example) (see Fig. 1 and Fig. 3 ).
  • the first outer surface has raised or naps produced by buffing, for example.
  • fiber web refers to the state before entangling of cut fibers
  • fiber sheet refers to the state after entangling and before PU resin filling
  • sheet refers to the state after PU resin filling and before dye finishing
  • artificial leather refers to the state of the product after dye finishing.
  • nonwoven fabric encompasses “fiber web”, “fiber sheet”, “sheet” and “artificial leather”
  • fibrous base material encompasses woven or knitted fabrics in addition to “nonwoven fabric”.
  • the single fibers are suitably aggregated, thus resulting in a smooth tactile sensation with a high luxuriant feel (high fiber bundle dispersibility).
  • the water flow dispersion treatment is preferably carried out by spraying of high-pressure water using a plurality of nozzles having nozzle hole intervals of 1.00 mm or smaller. As shown in Fig.
  • the nozzle hole interval is the distance in the nozzle width direction between a nozzle hole and the nozzle hole most adjacent to that nozzle hole in the nozzle width direction (whether nozzle holes are in a single row or in two or more rows). If the nozzle hole interval is 1.00 mm or smaller it will be possible to discharge a water stream with compact intervals onto the fiber sheet, dispersing the single fibers as single fiber bundles and helping to improve the luxuriant feel and slick feel. Water stream trajectories generated by the water flow dispersion treatment will also be less visible on the fiber sheet surface.
  • the nozzle hole interval is preferably 0.60 mm or smaller and even more preferably 0.30 mm or smaller.
  • the number of rows of nozzle holes opened in the widthwise direction of the water flow dispersion apparatus may be one or more rows.
  • the dewatering performance is not sufficient for the amount of loaded water, often resulting in impaired uniformity and shape stability of the fiber sheet.
  • multiple rows are provided, with the nozzle hole interval per single nozzle hole row widened to reduce the amount of water loaded per nozzle hole row, as a preferred means for helping to balance the amount of loaded water with the dewatering performance. For example, when a dewatering fault has occurred with a single nozzle row having a nozzle hole interval of 0.30 mm, and there are two nozzle rows with nozzle hole intervals of 0.60 mm in each row, then if the second row is placed so that nozzle hole rows with nozzle intervals of 0.60 mm are placed with a phase difference of 0.30 mm with respect to the first row, the water flow trajectory (nozzle hole interval) will be 0.30 mm, and an effect of improving dewatering faults can be obtained.
  • the nozzle hole interval is also preferably widened and multiple rows provided in order to facilitate nozzle processing.
  • the nozzle hole intervals (water flow trajectory) are preferably equal spacings in order to help produce uniform dispersion of the single fibers and prevent the water flow trajectories from being visible to allow improvement in the luxuriant feel and slick feel.
  • the inter-row distance of the nozzle holes in the case of a plurality of nozzle hole rows is preferably a distance corresponding to the nozzle hole intervals within the first nozzle row, for example, from the viewpoint of dewaterability.
  • the hole diameters of high-pressure water injection nozzle holes in water flow dispersion treatment are preferably 0.05 mm to 0.30 mm, more preferably 0.05 mm to 0.20 mm and even more preferably 0.08 mm to 0.13 mm, from the viewpoint of facilitating high dispersion of the single fibers, reducing visibility of water flow trajectories, and helping to obtain balance with the dewatering performance without an excessive amount of loaded water.
  • the water pressure of the water flow dispersion treatment is preferably spraying at 1.0 to 10.0 MPa. If the water pressure in the water flow dispersion treatment is 1.0 MPa or greater, the single fibers in the form of single fiber bundles will be more easily dispersed, and by limiting the water pressure in water flow dispersion treatment to no higher than 10.0 MPa, over-dispersion of the cut fiber bundles can be avoided to allow easier control of the k-nearest neighbor distance ratio to 10% to 80%. The single fibers in single fiber bundle form can also be dispersed, helping to reduce visibility of water flow trajectories.
  • a high water pressure during water flow dispersion treatment can sometimes cause the water stream to perforate the fiber sheet so that the energy is not used to disperse the single fiber bundles, and may instead result in a reduced dispersing effect for the single fiber bundles compared to low water pressure.
  • the water pressure for dispersion treatment is more preferably 1.5 to 7.0 MPa and even more preferably 2.0 to 4.5 MPa.
  • the manner of water stream discharge from the nozzle holes is preferably by using a plurality of nozzles to discharge a water stream with disturbance of 10% or greater.
  • Disturbance is an index of fluctuation in the diameter of a water stream.
  • the disturbance is preferably 12% or greater and even more preferably 15% or greater.
  • Moving the high-pressure water spraying nozzle with circular motion, or with reciprocal movement perpendicular to the processing direction (machine direction), is also preferred in terms of promoting dispersion of the single fibers and improving the luxuriant feel or slick feel.
  • the distance from the high-pressure water spraying surface to the product being treated is preferably 5 mm to 100 mm, more preferably 10 mm to 60 mm and even more preferably 20 mm to 40 mm, from the viewpoint of the single fiber bundle dispersing effect and of fabric guiding before water flow dispersion treatment, and processing throughput during the water flow dispersion treatment.
  • the cross-sectional PU resin area ratio in a cross-section of the fiber layer (A) in the thickness direction is 10% to 30%, and the standard deviation of the cross-sectional PU resin area ratio is 25% or lower.
  • the cross-sectional PU resin area ratio exceeds 30% the adhesion rate of PU resin will be too high, resulting in a stronger rubber-like feel for the artificial leather. This reduces the flexibility and produces a hard texture.
  • the cross-sectional PU resin area ratio is 10% or greater from the viewpoint of more easily obtaining adequate mechanical properties in the horizontal direction.
  • the cross-sectional PU resin area ratio is preferably 15% to 30%, more preferably 15% to 28% and even more preferably 15% to 26%.
  • the cross-sectional PU resin area ratio is determined by binarizing the PU resin in an SEM image as black portions, calculating the area ratio of PU resin for partitions from the binarized image by the partition method, and averaging the cross-sectional PU resin area ratio (%) for all of the partitions, while the standard deviation indicates variation from the average for each partition. If the standard deviation of the cross-sectional PU resin area ratio is 25% or lower, the distribution of PU resin mass sizes will be controlled, thus reducing variation in the texture (stiffness).
  • the standard deviation for the cross-sectional PU resin area ratio is preferably 25% or lower, more preferably 22% or lower and even more preferably 20% or lower. While the lower limit for the standard deviation of the cross-sectional PU resin area ratio is not particularly restricted it may be 0% or higher.
  • the cross-sectional PU resin area ratio can be controlled to 10% to 30%, for example, by impregnating a water-dispersed PU resin dispersion containing hot water-soluble resin microparticles (such as PVA resin fine particles), and then coagulating the PU resin by heating to obtain a sheet filled with the PU resin.
  • a water-dispersed PU resin dispersion containing hot water-soluble resin microparticles such as PVA resin fine particles
  • the average value of space sizes is preferably 5 ⁇ m to 35 ⁇ m in the thickness direction of the artificial leather.
  • the average space size is the average value in the thickness direction for the diameters ( ⁇ m) of maximum spheres that fit in the spaces excluding the single fibers composing the fiber layer (A) and the PU resin, as seen in a three-dimensional image of the fiber layer (A) by X-ray CT.
  • the average space size is an indicator of the dispersed state of structures composed of fibers and PU resin masses in the fiber layer (A) of the artificial leather.
  • a larger average space size means that the fibers and PU resin masses are closely adhering together. If the average space size is in the range of 5 ⁇ m to 35 ⁇ m, the fibers and PU resin will be suitably dispersed, to more easily provide texture (stiffness) of 28 cm or lower.
  • the average space size of the artificial leather as the final product can be controlled to 5 ⁇ m to 35 ⁇ m, for example, by impregnating the fiber sheet with the single fibers dispersed with a water-dispersed PU resin dispersion containing hot water-soluble resin microparticles (such as PVA resin fine particles), and then coagulating the PU resin by heating to obtain a fiber sheet filled with the PU resin.
  • the average space size is more preferably 5 ⁇ m to 25 ⁇ m and even more preferably 5 ⁇ m to 13 ⁇ m.
  • the adhesion rate of the PU resin in the fiber sheet is preferably 15 wt% to 50 wt%, more preferably 22 wt% to 45 wt% and even more preferably 26 wt% to 40 wt%.
  • the proportion of PU resin with respect to the fiber sheet affects how the cross-sectional PU resin area ratio and the average space size are controlled. With a low PU resin ratio, the cross-sectional PU resin area ratio tends to be low and the average space size tends to be large. With a high PU resin ratio, on the other hand, the cross-sectional PU resin area ratio tends to be high and the average space size tends to be small.
  • a PU resin ratio with respect to the fiber sheet of 15 wt% or greater will allow the fibers to be satisfactorily held by the PU resin, so that mechanical strength including abrasion resistance on a level satisfying commercial demand can be more easily obtained.
  • a PU resin ratio of 50 wt% or lower with respect to the fiber sheet will tend to result in a soft hand quality.
  • the PU resin is preferably obtained by reacting a polymer diol with an organic diisocyanate and a chain extender.
  • polymer diols to be used examples include polycarbonate-based, polyester-based, polyether-based, silicone-based and fluorine-based diols, and copolymers of any two or more of these may be used. From the viewpoint of hydrolysis resistance, it is preferred to use a polycarbonate-based or polyether-based diol, or a combination thereof. From the viewpoint of light fastness and heat resistance, polycarbonate-based or polyester-based diols, or their combinations, are preferred. From the viewpoint of cost competitiveness, a polyether-based or polyester-based diol, or a combination thereof, is preferred.
  • a polycarbonate-based diol can be produced by transesterification reaction of an alkylene glycol and a carbonic acid ester, or by reaction between phosgene or a chlorformic acid ester and an alkylene glycol.
  • alkylene glycols include straight-chain alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol and 1,10-decanediol; branched alkylene glycols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanediol; and aromatic diols such as bisphenol A; used either alone, or in any combinations of two or more.
  • straight-chain alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,
  • Polyester-based diols include polyester diols obtained by condensation between any of various low molecular weight polyols and polybasic acids.
  • low molecular weight polyols include one or more selected from among ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol and cyclohexane-1,4-dimethanol.
  • An addition product of an alkylene oxide with bisphenol A may also be used.
  • polybasic acids include one or more selected from the group consisting of succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid and hexahydroisophthalic acid.
  • polyether-based diols examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols comprising their combinations.
  • the number-average molecular weight of the polymer diol is preferably 500 to 4000.
  • the number-average molecular weight is 500 or higher and more preferably 1500 or higher to help prevent hardening of the texture.
  • the number-average molecular weight is 4000 or lower and more preferably 3000 or lower to help maintain satisfactory strength of the PU resin.
  • organic diisocyanates examples include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and xylylene diisocyanate; and aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, and their combinations may also be used. Preferred among these from the viewpoint of light fastness are aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate.
  • Chain extenders to be used include amine-based chain extenders such as ethylenediamine and methylenebisaniline, or diol-based chain extenders such as ethylene glycol.
  • amine-based chain extenders such as ethylenediamine and methylenebisaniline
  • diol-based chain extenders such as ethylene glycol.
  • a polyamine obtained by reacting a polyisocyanate and water may also be used as a chain extender.
  • the PU resin may also be used in the form of a solvent-type PU resin with the PU resin dissolved in an organic solvent such as N,N-dimethylformamide, or a water-dispersed PU resin with the PU resin emulsified with an emulsifying agent and dispersed in water.
  • a water-dispersed PU resin is preferred among these from the viewpoint of obtaining a finer form of the PU resin filling the fiber sheet, more easily obtaining the performance required for artificial leather such as texture and mechanical properties even with smaller amounts of addition, and not requiring the use of organic solvents so that the environmental load can be reduced.
  • the water-dispersed PU resin can be impregnated into a fiber sheet in the form of a dispersion with the PU resin dispersed with the desired particle size (hereunder also referred to as "PU resin dispersion"), the particle size can be controlled to satisfactorily manage the manner in which the PU resin fills the fiber sheet.
  • the water-dispersed PU resin used may be a self-emulsifying PU resin containing hydrophilic groups within the PU molecules, or a forced-emulsifying PU resin in which the PU resin has been emulsified with an external emulsifying agent.
  • a crosslinking agent may also be used with the water-dispersed PU resin in order to improve the durability, including resistance to moist heat, abrasion resistance and hydrolysis resistance.
  • a crosslinking agent is also preferably added to improve the durability during jet dyeing, reduce loss of the fibers and obtain excellent surface quality.
  • the crosslinking agent may be an external crosslinking agent added as an addition component to the PU resin, or it may be a reactive group-introducing internal crosslinking agent that can produce a crosslinked structure beforehand within the PU resin structure.
  • the water-dispersed PU resin used in the artificial leather will generally have a crosslinked structure to provide dyeing resistance, it tends to be poorly soluble in organic solvents such as N,N-dimethylformamide. Therefore when observing a cross-section with an electron microscope, for example, if a resinous substance remains which lacks the form of the fibers after immersion of the artificial leather in N,N-dimethylformamide at room temperature for 12 hours to dissolve the PU resin, the resinous substance may be judged to be the water-dispersed PU resin.
  • the PU resin is filled using a PU resin dispersion, and the mean primary particle size of the PU resin in the dispersion is preferably 0.1 ⁇ m to 0.8 ⁇ m, more preferably 0.1 ⁇ m to 0.6 ⁇ m and even more preferably 0.2 ⁇ m to 0.5 ⁇ m.
  • the mean primary particle size is the value obtained by measurement of the PU resin dispersion using a laser diffraction particle size distribution analyzer ("LA-920" by Horiba, Ltd.).
  • the mean primary particle size of the PU resin is 0.1 ⁇ m or greater, then the force with which the PU resin holds the fibers together in the fiber sheet (binding force) will be satisfactory, allowing artificial leather with excellent mechanical strength to be obtained. Limiting the mean primary particle size of the PU resin to 0.8 ⁇ m or smaller will inhibit aggregation and coarseness of the PU resin, which is advantageous for controlling the standard deviation of the cross-sectional PU resin area ratio to 25% or lower.
  • the mean primary particle size of the PU resin in the PU resin dispersion is 0.1 ⁇ m to 0.8 ⁇ m, then the fibers composing the artificial leather (surface layer) will be held together at more points, allowing a soft hand quality (stiffness) and excellent mechanical strength (such as abrasion resistance) to be obtained.
  • the PU resin is impregnated as an impregnating liquid in the form of a solution (dissolved in a solvent) or dispersion (water-dispersed).
  • the solid concentration of the water-dispersed PU resin dispersion may be 10 wt% to 35 wt%, for example, and is preferably 15 to 30 wt% and more preferably 15 to 25 wt%.
  • the impregnating liquid is prepared and impregnated into the fiber sheet so that the adhesion rate of the PU resin with respect to 100 wt% of the fiber sheet is 15 wt% to 50 wt%.
  • the impregnating liquid containing the PU resin may also contain additives such as stabilizers (ultraviolet absorbers and antioxidants), flame retardants, antistatic agents and pigments (such as carbon black), as necessary.
  • the total amount of additives in the artificial leather may be 0.1 to 10.0 parts by mass, 0.2 to 8.0 parts by mass or 0.3 to 6.0 parts by mass, for example, with respect to 100 parts by mass of the PU resin. Such additives become distributed in the PU resin of the artificial leather.
  • the values of the size of the PU resin and the mass ratio with respect to the fiber sheet mentioned herein are assumed to include the additives (when used).
  • the water-dispersed PU resin dispersion containing the hot water-soluble resin microparticles is impregnated into the fiber sheet and the PU resin is subsequently coagulated by heating to obtain the sheet filled with the PU resin.
  • the hot water-soluble resin microparticles are removed from the fiber sheet using hot water, thus dividing part of the continuous layer of the PU resin and forming pores, to micronize the state of adhesion of the PU resin.
  • the hot water-soluble resin microparticles may be partially saponified PVA resin fine particles or completely saponified PVA resin fine particles. Since completely saponified PVA resin fine particles tend to be less elutable into water at ordinary temperature(or room temperature) (20°C) compared to partially saponified PVA resin fine particles, completely saponified PVA resin fine particles are preferably used as the hot water-soluble resin microparticles. From the viewpoint of inhibiting elution into water at ordinary temperature (20°C), the saponification degree of completely saponified PVA resin fine particles is preferably 95 mol% or greater and more preferably 98 mol% or greater.
  • the mean particle size (size) of the hot water-soluble resin microparticles is preferably 1 ⁇ m to 8 ⁇ m, more preferably 2 ⁇ m to 6 ⁇ m and even more preferably 2 ⁇ m to 4 ⁇ m. If the mean particle size is 1 ⁇ m or greater the hot water-soluble resin microparticles will be less likely to aggregate, and if the mean particle size is 8 ⁇ m or smaller the hotwater-soluble resin microparticles will be more satisfactorily impregnated into the fiber sheet.
  • the microparticles used may be "NL-05" by Mitsubishi Chemical Holdings Corp., and micronization of the hot water-soluble resin microparticles may be by the method described in Japanese Unexamined Patent Publication HEI No. 7-82384 .
  • the content of hot water-soluble resin microparticles in the water-dispersed PU resin dispersion is preferably 1 wt% to 20 wt%, more preferably 2 wt% to 15 wt% and even more preferably 3 wt% to 10 wt%.
  • a content of 1 wt% or greater of the hot water-soluble resin microparticles in the water-dispersed PU resin dispersion will tend to promote dispersion of the PU resin masses.
  • a content of 20 wt% or lower of the hot water-soluble resin microparticles in the water-dispersed PU resin dispersion on the other hand, will tend to maintain a stable dispersion without aggregation of the microparticles.
  • hot water-soluble resin refers to a resin that is poorly soluble in water at ordinary temperature.
  • a step of adhering the hot water-soluble resin to the fiber sheet may be carried out before the water-dispersed PU resin dispersion containing the hot water-soluble resin microparticles is impregnated into the fiber sheet.
  • the method of adhering the hot water-soluble resin (such as a PVA resin) may be preparation of an aqueous solution of the hot water-soluble resin followed by impregnation of the fiber sheet with the water-soluble solution and drying.
  • Removing the hot water-soluble resin together with the hot water-soluble resin microparticles from the fiber sheet using hot water in the finishing-process steps or dyeing step can inhibit adhesion between the fibers and PU resin or can divide part of the continuous layer of the PU resin and form pores to micronize the state of adhesion of the PU resin, thus tending to improve the texture of the artificial leather.
  • the hot water-soluble resin may be a partially saponified PVA resin or completely saponified PVA resin. Since a completely saponified PVA resin tends to be less elutable into water at ordinary temperature (20°C) compared to a partially saponified PVA resin, a completely saponified PVA resin is preferably used as the hot water-soluble resin. From the viewpoint of inhibiting elution into water at ordinary temperature (20°C), the saponification degree of the completely saponified PVA resin is preferably 95 mol% or greater and more preferably 98 mol% or greater. In order to increase the permeability of the aqueous hot water-soluble resin solution during impregnation, the polymerization degree is preferably 1000 or lower and more preferably 700 or lower.
  • the fiber sheet 1 includes at least the fiber layer (A) 12, while the scrim 11 and fiber layer (B) 13 are optional and are not essential elements.
  • the artificial leather of this embodiment may therefore be a single layer of the fiber layer (A), or two layers consisting of the fiber layer (A) and the scrim or fiber layer (B), or three layers consisting of the fiber layer (A), the scrim and the fiber layer (B).
  • the fiber layer (A) may be a single-layer fiber sheet which is sliced in half horizontally and then filled with the PU resin, as explained below.
  • the fiber sheet has a monolayer structure with no scrim. This will allow productivity to be increased by slicing in half horizontally.
  • the fiber sheet has a three-layer structure with a scrim as the intermediate layer.
  • a woven or knitted fabric scrim 11 may be inserted in a sandwich manner between the fiber layer (A) 12 constituting the first outer surface of the artificial leather and the fiber layer (B) 13 constituting the second outer surface of the artificial leather, forming a three-layer structure with the fibers tangled between the layers, which is preferred for dimensional stability, tensile strength and tear strength.
  • a three-layer structure of the fiber layer (A), fiber layer (B) and a scrim inserted between them also allows the fiber layer (A) and fiber layer (B) to be have separate designs, and is therefore preferred from the viewpoint of free customization of the diameters and types of fibers composing each layer to match the functions and usages required for artificial leather.
  • using ultrafine fibers for fiber layer (A) and flame-retardant fibers for fiber layer (B) allows both excellent surface quality and high flame retardance to be obtained.
  • a woven or knitted fabric scrim is preferably made of a polymer of the same type as the fibers composing the fiber layer (A), from the viewpoint of obtaining the same color by dyeing.
  • the fibers of the fiber layer (A) are polyester-based, for example, the fibers of the scrim are also preferably polyester-based, and when the fibers of the fiber layer (A) are polyamide-based the fibers of the scrim are also preferably polyamide-based.
  • a knitted fabric scrim it is preferably a single knit of 22 gauge to 28 gauge.
  • a woven fabric scrim can exhibit higher dimensional stability and strength than a knitted fabric.
  • the woven fabric texture may be a plain weave, twill weave or satin weave, but is preferably a plain weave from the viewpoint of cost and entangling properties.
  • the yarn composing the woven fabric may be monofiber or multifiber yarn.
  • the single fiber fineness of the yarn is preferably 5.5 dtex or smaller to more easily obtain flexible artificial leather.
  • the form of the yarn composing the woven fabric may be multifiber gray yarn of polyester or polyamide, or false twisted finished yarn with added twisting of 0 to 3000 T/m.
  • multifibers When multifibers are used they may be common ones, and are preferably 33 dtex/6f, 55 dtex/24f, 83 dtex/36f, 83 dtex/72f, 110 dtex/36f, 110 dtex/48f, 167 dtex/36f or 166 dtex/48f polyester or polyamide, for example.
  • the yarn composing a woven fabric may be multifiber long fibers.
  • the woven density of the yarn in a woven fabric is preferably 30 to 150/inch and more preferably 40 to 100/inch from the viewpoint of obtaining artificial leather that is flexible with excellent mechanical strength.
  • the basis weight of the woven fabric is preferably 20 to 150 g/m 2 .
  • the presence or absence of false twisting, the number of twists, the multifiber single fiber fineness and woven density for a woven fabric also contribute to the entangling properties between the fibers composing the fiber layer (A) and the optional fiber layer (B), and to the mechanical properties including flexibility, seam strength, tearing strength, tensile strength and elongation and stretchability of the artificial leather, and they may be selected as appropriate for the desired physical properties and intended use.
  • the fiber layer (A) in the artificial leather of this embodiment is preferably composed of fibers with mean diameters of 1 ⁇ m to 8 ⁇ m, more preferably 2 ⁇ m to 6 ⁇ m and even more preferably 2 ⁇ m to 5 ⁇ m. If the mean diameter of the fibers is 1 ⁇ m or greater, the abrasion resistance, dye coloring properties and light fastness will be satisfactory. If the mean diameter of the fibers is 8 ⁇ m or smaller, on the other hand, the large number density of the fibers will result in a high luxuriant feel and smooth surface tactile sensation, to obtain artificial leather with more satisfactory surface quality.
  • the fibers composing the fiber layers of the artificial leather may be synthetic fibers, which includes polyester-based fibers such as polyethylene terephthalate, polybutylene terephthalate and polytrimethylene terephthalate; and polyamide-based fibers such as nylon 6, nylon 66 and nylon 12.
  • polyester-based fibers such as polyethylene terephthalate, polybutylene terephthalate and polytrimethylene terephthalate
  • polyamide-based fibers such as nylon 6, nylon 66 and nylon 12.
  • polyethylene terephthalate is preferred among these from the viewpoint of excellent color fastness without yellowing of the fibers themselves when exposed to direct sunlight for long periods.
  • the fibers composing the fiber layer of the artificial leather are more preferably made of chemical-recycled or material-recycled polyethylene terephthalate, or polyethylene terephthalate obtained using a plant-derived starting material.
  • the fibers are "dispersed as single fibers", it means that the fibers do not form fiber bundles similar to the island-component in sea-island composite fibers, for example.
  • Fibers obtained using fibers capable of ultrafine fiber generating such as sea-island composite fibers (with copolymerized polyester as the sea-component and regular polyester as the island-component, for example), with micronizing treatment after three-dimensional entangling with a scrim (removal of the sea-component of the sea-island composite fibers by dissolving decomposition) are present as fiber bundles in the fiber layer (A) and are not dispersed as single fibers.
  • sea-island composite cut fibers with an island-component having a single fiber fineness equivalent to 0.2 dtex and 24 island/1f and forming a fiber layer (A) of the sea-island composite cut fibers, and then forming a three-dimensional tangled composite with a scrim by needle punching treatment, filling the three-dimensional tangled composite with a PU resin and dissolving or decomposing the sea-component, it is possible to obtain ultrafine fibers with a single fiber fineness equivalent to 0.2 dtex.
  • the single fibers are present in the fiber layer (A) in a state of fiber bundles with 24 per bundle (equivalent to 4.8 dtex in the bundled state).
  • the fiber layer (A) is composed of fibers dispersed as single fibers it is easier to obtain excellent surface smoothness, for example, having uniform naps when the outer surface of the fiber layer (A) has been raised by buffing treatment, and resistance to formation of fiber balls known as "pilling" on the outer surface due to abrasion, even with a relatively low adhesion rate of the PU resin, and therefore artificial leather with more excellent surface quality and abrasion resistance can be obtained.
  • Having the fibers dispersed as single fibers also tends to result in uniform narrow intervals between the fibers, thus providing satisfactory abrasion resistance even though the PU resin is adhering in a micronized form.
  • the method of dispersing the fibers as single fibers may be a method of using a papermaking method to form a fiber sheet of the fibers produced by direct spinning, or a method of dissolving or decomposing the sea-component of a fiber sheet fabricated with sea-island composite fibers to generate ultrafine fiber bundles, and then carrying out the aforementioned water flow dispersion treatment on the ultrafine fiber bundle surfaces to promote formation of single fibers of the ultrafine fiber bundles.
  • the fibers in a fiber layer other than the fiber layer (A) composing the artificial leather may optionally be or may not be dispersed as single fibers, but according to a preferred aspect, layers other than the fiber layer (A) are also composed of fibers dispersed as single fibers.
  • the fibers composing layers other than the fiber layer (A) are preferably dispersed as single fibers from the viewpoint of forming a uniform thickness of the artificial leather and improving the processing accuracy, and stabilizing the quality, and also from the viewpoint of providing an equal outer appearance on both the front and back of the artificial leather.
  • the basis weight of the fibers of the fiber layer (A) is preferably 40 g/m 2 to 500 g/m 2 , more preferably 50 g/m 2 to 370 g/m 2 and even more preferably 60 g/m 2 to 320 g/m 2 , from the viewpoint of mechanical strength including abrasion resistance.
  • the basis weight of the fibers of the fiber layer (A) is preferably 10 g/m 2 to 200 g/m 2 , more preferably 30 g/m 2 to 170 g/m 2 and even more preferably 60 g/m 2 to 170 g/m 2 , from the viewpoint of mechanical strength including abrasion resistance.
  • the basis weight of the fibers of the fiber layer (B) is preferably 10 g/m 2 to 200 g/m 2 and more preferably 20 g/m 2 to 170 g/m 2 , from the viewpoint of cost and facilitated production.
  • the basis weight of the scrim is preferably 20 g/m 2 to 150 g/m 2 , more preferably 20 g/m 2 to 130 g/m 2 and even more preferably 30 g/m 2 to 110 g/m 2 from the viewpoint of mechanical strength and entangling between the fiber layers and scrim.
  • the basis weight of the artificial leather filled with the PU resin is preferably 50 g/m 2 to 550 g/m 2 , more preferably 60 g/m 2 to 400 g/m 2 and even more preferably 70 g/m 2 to 350 g/m 2 .
  • the texture (stiffness) of the artificial leather is preferably 28 cm or lower, more preferably 6 cm to 26 cm and even more preferably 8 cm to 22 cm.
  • the stiffness is an index representing the texture of the artificial leather. If the stiffness is 28 cm or lower the moldability of the sheet into covering materials or interior finishing materials for interiors, automobiles, aircraft and railway vehicles will be improved and the consumption performance will be satisfactory, while the flexibility will also be more satisfactory for market demand.
  • the luxuriant feel (fiber bundle dispersibility) of the artificial leather is preferably grade 4.0 or higher and more preferably grade 5.0 or higher.
  • the luxuriant feel (fiber bundle dispersibility) is a value for assessing compactness of piles on a 7-level scale, based on visual and tactile organoleptic evaluation.
  • a luxuriant feel of grade 4.0 or higher will provide the quality of the sheet as a covering material or interior finishing material for interiors, automobiles, aircraft and railway vehicles.
  • the method of producing each fiber layer forming the fiber sheet of the artificial leather may be a direct spinning method (such as a spunbond method or meltblown method), or a method of forming a fiber sheet with cut fibers (such as a carding method, airlaid method or other dry method, or a wet method such as a papermaking method), which are all suitable, but for this embodiment sea-island fibers (SIF) are used as the starting material.
  • a fiber sheet produced using the cut fibers is preferred because it has low basis weight variation and excellent homogeneity, and tends to form uniform piles and thus improve the surface quality for artificial leather.
  • Fibers capable of ultrafine fiber generating may be used to form the ultrafine fibers of the fiber sheet. Using fibers capable of ultrafine fiber generating can stabilize the entangling forms of the ultrafine fiber bundles.
  • the fibers capable of ultrafine fiber generating used may be sea-island fibers having two thermoplastic resin components with different solvent solubilities as the sea-component and island-component, with the island-component as the ultrafine fibers by dissolving removal of the sea-component with a solvent, or peelable composite fibers having two thermoplastic resin components situated alternately in a radial or multilayer manner in the fiber cross-sections and being split into ultrafine fibers by peeled splitting of the components.
  • Sea-island fibers can provide suitable voids between the island-component (ultrafine fibers) by removal of the sea-component, and are therefore preferred for use from the viewpoint of flexibility and texture of the sheet.
  • Sea-island fibers include sea-island composite fibers obtained by spinning the sea-component and island-component in mutual alignment using a sea-island compositing nozzle, and sea-island mixed fibers obtained by spinning a mixture of the sea-component and island-component. Sea-island composite fibers are preferably used from the viewpoint of obtaining ultrafine fibers of uniform fineness and of obtaining ultrafine fibers of adequate length to contribute to the sheet strength.
  • the sea-component for sea-island fibers may be a copolymerized polyester obtained by copolymerizing polyethylene, polypropylene, polystyrene, sodiumsulfoisophthalic acid or polyethylene glycol, or polylactic acid.
  • a copolymerized polyester obtained by copolymerizing polyethylene, polypropylene, polystyrene, sodiumsulfoisophthalic acid or polyethylene glycol, or polylactic acid.
  • an alkali-decomposable copolymerized polyester obtained by copolymerizing sodiumsulfoisophthalic acid or polyethylene glycol, or polylactic acid, which can be decomposed without using organic solvents.
  • the sea-component is preferably removed before the PU resin is applied to the fiber sheet. Removal of the sea-component before application of the PU resin allows the ultrafine fibers to be firmly held since the structure has the PU resin directly adhering to the ultrafine fibers, and therefore results in satisfactory abrasion resistance of the sheet.
  • the method of entangling the fibers or fiber bundles of the fiber web may be by cutting the sea-island fibers to predetermined fiber lengths to form cut fibers, passing them through a card and cross lapper to form a fiber web, and entangling them by hydroentangling treatment by means of a needle punching or spunlace method.
  • the number of needle barbs used is preferably 1 to 9. If the number of barbs is 1 or greater an entangling effect will be obtained and damage to the fibers can be minimized. If the number of barbs is 9 or less, damage to the fibers can be reduced and fewer needle marks will be left in the artificial leather, allowing the outer appearance of the product to be improved.
  • the total barb depth (length from the tip to the base of the barb) is preferably 0.05 mm to 0.10 mm. If the total barb depth is 0.05 mm or greater, the barbs will be able to satisfactorily hook the fibers, allowing efficient fiber entangling to be achieved. If the total barb depth is 0.10 mm or less, fewer needle marks will be left on the artificial leather, resulting in improved quality. Considering the balance between barb strength and fiber entangling, the total barb depth is more preferably 0.06 mm to 0.08 mm.
  • the punch density range is preferably 300/cm 2 to 6000/cm 2 and more preferably 1000/cm 2 to 6000/cm 2.
  • the fiber sheet obtained by needle punching may be immersed for 2 minutes in 98°C water for shrinkage, and dried at a temperature of 100°C for 5 minutes to form the fiber sheet prior to sea removal.
  • Removal of the sea-component may be carried out by immersing the sea-island fibers in a solvent to cause constriction.
  • the solvent used to dissolve the sea-component may be an aqueous alkali solution of sodium hydroxide or the like when the sea-component is a copolymerized polyester or polylactic acid.
  • the removal of the sea-component is preferably carried out with an aqueous alkali solution of sodium hydroxide.
  • the cut fiber lengths are preferably 13 mm to 102 mm, more preferably 25 mm to 76 mm and even more preferably 38 mm to 76 mm for a dry method (carding method or airlaid method), and preferably 1 mm to 30 mm, more preferably 2 mm to 25 mm and even more preferably 3 mm to 20 mm for a wet method (papermaking method).
  • the aspect ratio (L/D) as the ratio of the length (L) and diameter (D), is preferably 500 to 2000 and more preferably 700 to 1500.
  • This aspect ratio range is preferred because the dispersibility and dispersibility of the cut fibers in the slurry of the cut fibers dispersed in water will be satisfactory during preparation of the slurry, the fiber layer strength will be satisfactory, and fiber balls known as "pilling" caused by abrasion will be less likely to be outwardly apparent since the fiber lengths are shorter than by a dry method, allowing the single fibers to more easily disperse.
  • the fiber lengths of cut fibers with diameters of 4 ⁇ m, for example, are preferably 2 mm to 8 mm and more preferably 3 mm to 6 mm.
  • the fiber sheet is impregnated with a water-dispersed PU resin dispersion containing hot water-soluble resin microparticles, and then the PU resin is anchored by heating to fill the sheet with the PU resin.
  • the PU resin is impregnated as an impregnating liquid in the form of a dispersion (water-dispersed form).
  • the concentration of the PU resin in the impregnating liquid may be 10 to 35 wt%, for example.
  • the impregnating liquid is prepared and impregnated into the fiber sheet so that the ratio of the PU resin is 15 to 50 wt% with respect to 100 wt% of the fiber sheet.
  • Water-dispersed PU resins are classified as forced-emulsifying PU resins that are forcibly dispersed and stabilized using a surfactant, and self-emulsifying PU resins that have a hydrophilic structure in the PU molecule and disperse and stabilize in water without the presence of a surfactant. While either may be used for this embodiment, forced-emulsifying PU resins are preferably used from the viewpoint of imparting a heat-sensitive coagulating property as explained below.
  • the fiber sheet is impregnated with a water-dispersed PU resin dispersion containing hot water-soluble resin microparticles, but it is not preferred for the hot water-soluble resin microparticles to dissolve in the water-dispersed PU resin dispersion. Since the hot water-soluble resin microparticles are less soluble in a water-soluble solution with a dissolved surfactant than in water, a forced-emulsifying PU resin dispersion that contains a surfactant is more preferred than a self-emulsifying PU resin dispersion that does not contain a surfactant.
  • the concentration of the water-dispersed PU resin (the content of the PU resin with respect to the water-dispersed PU resin dispersion) is preferably 10 to 35 wt%, more preferably 15 to 30 wt% and even more preferably 15 to 25 wt%, from the viewpoint of controlling the amount of adhesion of the water-dispersed PU resin and because a high concentration promotes aggregation of the PU resin and reduces the stability of the impregnating liquid.
  • the water-dispersed PU resin dispersion preferably has a heat-sensitive coagulating property.
  • a heat-sensitive coagulating property is a property such that when the PU resin dispersion is heated, the PU resin dispersion loses fluidity and solidifies upon reaching a certain temperature (the heat-sensitive coagulation temperature).
  • the fiber sheet After the fiber sheet has been impregnated with the PU resin dispersion during production of the sheet filled with a PU resin, it is coagulated by dry heat coagulation, moist heat coagulation, hot water coagulation or a combination thereof, and dried to apply the PU resin to the fiber sheet.
  • the method currently used in industrial production for coagulating water-dispersed PU resin dispersions that do not exhibit a heat-sensitive coagulating property is dry coagulation, but this tends to cause the migration in which the PU resin becomes concentrated in the surface layer of the sheet, tending to result in hardening of the texture of the sheet filled with the PU resin.
  • the heat-sensitive coagulation temperature of the water-dispersed PU resin dispersion is preferably 40 to 90°C. If the heat-sensitive coagulation temperature is 40°C or higher, the storage stability of the PU resin dispersion will be satisfactory and pollution of operating machinery by the PU resin can be inhibited. If the heat-sensitive coagulation temperature is 90°C or lower, migration of the PU resin in the fiber sheet can be inhibited.
  • a heat-sensitive coagulant may be added as appropriate to adjust the heat-sensitive coagulation temperature to the range specified above.
  • heat-sensitive coagulants include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate and calcium chloride, and radical reaction initiators such as sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile and benzoyl peroxide.
  • the water-dispersed PU resin dispersion may be impregnated and coated onto the fiber sheet, and subjected to dry heat coagulation, moist heat coagulation, hot water coagulation or a combination of these, to coagulate the PU resin.
  • the temperature for moist heat coagulation is preferably 40 to 200°C, and above the heat-sensitive coagulation temperature of the PU resin. If the moist heat coagulation temperature is 40°C or higher and more preferably 80°C or higher, then it will be possible to shorten the time until coagulation of the PU resin and better inhibit its migration. If the moist heat coagulation temperature is 200°C or lower and more preferably 160°C or lower, heat degradation of the PU resin or PVA resin can be prevented.
  • the temperature for hot water coagulation is preferably 40 to 100°C, and above the heat-sensitive coagulation temperature of the PU resin. If the hot water coagulation temperature in hot water is 40°C or higher and more preferably 80°C or higher, then it will be possible to shorten the time until coagulation of the PU resin and better inhibit its migration.
  • the dry coagulation temperature and drying temperature are preferably 80 to 180°C. A dry coagulation temperature and drying temperature of 80°C or higher and more preferably 90°C or higher will result in excellent productivity. If the dry coagulation temperature and drying temperature are 180°C or lower and more preferably 160°C or lower, heat degradation of the PU resin or PVA resin can be prevented.
  • the content of the hot water-soluble resin microparticles in the water-dispersed PU resin dispersion is preferably 1 wt% to 20 wt%, more preferably 2 wt% to 15 wt% and even more preferably 3 wt% to 10 wt%.
  • Including hot water-soluble resin microparticles in the water-dispersed PU resin dispersion further promotes dispersion of the PU resin masses.
  • the means for removing the hot water-soluble resin from the sheet may be, for example, a method of immersion in hot water at 60°C or higher and preferably 80°C or higher, or a method of removing the hot water-soluble resin microparticles while circulating hot water at 80°C or higher in a jet dyeing machine before dyeing.
  • a method of removing the hot water-soluble resin microparticles in a jet dyeing machine is especially preferred because it can eliminate the steps of drying and winding of the sheet after removal of the hot water-soluble resin microparticles, and thus increase production efficiency.
  • removal of the hot water-soluble resin microparticles from the sheet after application of the PU resin yields a flexible sheet. While the method of removing the hot water-soluble resin microparticles is not particularly restricted, a preferred aspect is dissolving removal by immersion of the sheet in hot water at 60 to 100°C, with squeezing using a mangle if necessary.
  • the sheet filled with the PU resin may be sliced in half horizontally, if it does not include a scrim. This can increase production efficiency.
  • the PU resin-filled sheet may have a lubricant applied, such as a silicone dispersion.
  • a lubricant such as a silicone dispersion.
  • Application of an antistatic agent before buffing treatment is also preferred so that grinding powder generated from the sheet by grinding will be less likely to accumulate on sandpaper.
  • Buffing treatment may be carried out to form naps on the surface of the sheet.
  • the buffing treatment may be by a method of grinding using sandpaper or a roll sander. Applying silicone as a lubricant before buffing treatment allows naps to be easily formed by surface grinding, resulting in very satisfactory surface quality.
  • the artificial leather is preferably subjected to dyeing treatment to increase the value for sensibility (i.e. the visual effect).
  • Dyeing may be selected according to the type of fibers composing the fiber sheet, and for example, a disperse dye stuff may be employed for polyester-based fibers, an acid dye or gold-containing dye may be employed for polyamide-based fibers, or any combination of such dyes may be used. When a disperse dye stuff has been used for dyeing, the dyeing may be followed by reduction cleaning.
  • the dyeing method used may be any one commonly known in the dyeing industry. The dyeing method preferably employs a jet dyeing machine to simultaneously provide a rubbing effect while the sheet is dyed, in order to soften the sheet.
  • the dyeing temperature will depend on the type of fiber but is preferably 80 to 150°C. If the dyeing temperature is 80°C or higher and more preferably 110°C or higher it will be possible to efficiently dye the fibers. If the dyeing temperature is 150°C or lower and more preferably 130°C or lower it will be possible to prevent degradation of the PU resin.
  • the artificial leather dyed in this manner is preferably subjected to soaping and if necessary reduction cleaning (ore reduction washing) (cleaning in the presence of a chemical reducing agent) to remove the excess dye. It is also preferred to use a dyeing aid during dyeing. Using a dyeing aid can increase the dyeing uniformity and reproducibility. Whether in the same bath as dyeing or after dyeing, finishing process may be carried out using a flexibilizer such as silicone, or an antistatic agent, water-repellent agent, flame retardant, light fastness agent or antimicrobial agent.
  • a flexibilizer such as silicone, or an antistatic agent, water-repellent agent, flame retardant, light fastness agent or antimicrobial agent.
  • the artificial leather of this embodiment can be suitably used as an interior finishing material with a very delicate outer appearance when used as a covering material for furniture, chairs, wall materials, or for seats, ceilings or interior finishings for vehicle interiors of automobiles, electric railcars or aircraft, or as clothing materials used in parts of shirts, jackets, uppers or trims for shoes including casual shoes, sports shoes, men's shoes or women's shoes, or bags, belts and wallets, or even as industrial materials such as wiping cloths, abrasive cloths or CD curtains.
  • 10 locations at roughly equal distances in the machine direction (MD) of the fiber layer (A) or the artificial leather comprising the fiber layer (A) are cut out into strips (shown by dotted lines).
  • a cross-section is formed in the thickness (t) direction.
  • the cross-section formed in the thickness (t) direction is conductively treated by coating with osmium atoms to 1 nm.
  • SEM images are taken at 10 locations at roughly equal distances in the CD perpendicular to the MD, to determine the single fiber cross-sectional k-nearest neighbor distance ratio (%) and cross-sectional PU resin area ratio (%) for the cross-section.
  • the first outer surface of the fiber layer (A) from each of the 10 locations at roughly equal distances in the CD is conductively treated by coating with osmium atoms to 1 nm, and SEM images of the first outer surface are taken.
  • a three-dimensional images are taken of the 10 locations at roughly equal distances in the CD by X-ray CT. Each image is used to determine the single fiber cross-sectional k-nearest neighbor distance ratio (%), cross-sectional PU resin area ratio (%) and space size, and 100 copies of each image are prepared. Therefore, the average value and the standard deviation are for 100 images.
  • the nap direction is the MD.
  • the sample may be cut out in the direction perpendicular to any arbitrary direction.
  • the k-nearest neighbor algorithm is a method in which k number of single fiber cross-sections near an arbitrary single fiber cross-section are taken and the kth nearest radius by Euclidean distance is used as the decision boundary.
  • the observation region is the maximum depth of the fiber layer (A) of the cut surface of the conductively treated sample (i.e. the part furthest on the scrim side), and observation is with a scanning electron microscope (SEM, "JSM-5610" by JEOL Corp.), ignoring the fibers forming the scrim.
  • SEM scanning electron microscope
  • the single fiber cross-section in the SEM image may be manually marked for identification, as shown in Fig. 4 .
  • the specific procedure is as follows.
  • the Euclidean distance to the kth nearest fiber cross-section is calculated for all of the fiber cross-sections (k-nearest neighbor distance: matrix distance).
  • the number of cross-sections with k-nearest neighbor distance of R or less is divided by the total number of fiber cross-sections, and used as the k-nearest neighbor distance ratio for the SEM image.
  • the locations of the fiber cross-sections may be determined with manual marking replaced by machine learning (deep learning) where classification is on the pixel level based on semantic segmentation using the 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)), all consisting of convolution layers, and using an image containing teacher data with red (R) dots marked on the fiber cross-section (correct labels) as the learning data.
  • FCN Full Convolutional Networks
  • the sample of the cross-section in the thickness direction is cut to 1 cm ⁇ 0.5 cm (width (x) ⁇ height (y)), and the interior space of the sample is embedded with an epoxy-based resin (base compound: "Quetol812" by Nisshin-EM, curing agent: “MNA” by Nisshin-EM, accelerator: "DMP-30” by Nisshin-EM).
  • base compound “Quetol812" by Nisshin-EM
  • accelerator “DMP-30” by Nisshin-EM
  • the obtained resin-embedded sample is cut parallel to the thickness direction with a microtome to obtain a smooth cut surface. It is then exposed for 4 hours to saturated vapor of ruthenium tetroxide, and the PU resin adhering to the sample is electron stained with ruthenium. It is subsequently coated with osmium atoms to 1 nm for conductive treatment.
  • the observation region is the maximum depth of the fiber layer (A) of the cut surface of the conductively treated sample (i.e. the part furthest on the scrim side), and observation is with a scanning electron microscope (SEM, "SU8220" by Hitachi High-Technologies Corp.), ignoring the fibers forming the scrim.
  • SEM scanning electron microscope
  • observation is made with the SEM using the center section in the thickness direction of the artificial leather in the cut surface of the conductively treated sample as the center point of the observation region.
  • the observation conditions are as follows.
  • the obtained SEM backscattered electron image is binarized by the following method using "ImageJ” image analysis software (version: 1.51j8, National Institutes of Health, USA), and the average size of the PU resin is determined.
  • Handpass filter processing Filter large structures down to 40 pixels, Filter small structures up to 3 pixels, Suppress stripes None, Tolerance of direction: 5%, Autoscale after filtering, Saturate image when autoscaling, and for median filter processing, radius: 4, single filtering operation.
  • the numbers of pixels are read off in the x and y-axis of the image, the partition size is specified by pixel size, the number of partitions on the x and y-axis are determined, and the PU resin area% in each divided region is calculated.
  • the area ratio of PU resin calculated from a single SEM image is the average of the PU resin area ratios for all of the partitions in the single SEM image, and the standard deviation is calculated by the formula shown in Fig. 6 .
  • the cross-sectional PU resin area ratio (%) and standard deviation are the average values of the PU resin area ratios and standard deviations calculated from each of the SEM images, for 100 images. As shown in Fig. 6 , first the standard deviation for all of the partitions divided in a single SEM image is calculated, and the mean of the standard deviations calculated for each of 100 SEM images is recorded as the standard deviation.
  • the mean diameter of fibers composing the fiber layer (A) is determined by taking 10 SEM images of a cross-section of the fiber layer (A) in the thickness direction forming the artificial leather using a scanning electron microscope (SEM, "JSM-5610" by JEOL Corp.), at a magnification of 1500x, randomly selecting 100 fibers on the first outer surface of the artificial leather, measuring the diameters of the single fiber cross-sections, and determining the arithmetic mean value for the 100 fibers.
  • SEM scanning electron microscope
  • the distance between the outer circumferences on a straight line perpendicular to the middle point of the longest diameter of the single fiber cross section was taken as the fiber diameter.
  • Fig. 2 is a conceptual drawing illustrating how a fiber diameter is determined.
  • the fiber diameter is considered to be the outer circumferential distance c on a straight line b perpendicular to the midpoint p of the maximum diameter "a" of the cross-section A in the observed image.
  • the average value in the thickness direction for the diameters ( ⁇ m) of maximum spheres that fit in the spaces excluding the fibers composing the fiber layer (A) and the PU resin masses, as seen in a three-dimensional image of the fiber layer (A) by X-ray CT, is used as the average space size, determined by the following procedure.
  • the space size ( ⁇ m) and standard deviation are average values calculated for a 100-slice three-dimensional image obtained by X-ray CT.
  • the observation region is the maximum depth (i.e. the part furthest on the scrim side) of the fiber layer (A), and the image is take with an X-ray CT device ("high-resolution 3D X-ray microscope" by Rigaku Corp.), excluding the fibers of the scrim.
  • the images are taken using the center of the thickness of the cross-section in the thickness direction as the center point of the observation region.
  • Each sample was cut to a 20 cm ⁇ 20 cm square for use as a measuring sample.
  • the measuring sample was set on a horizontal surface, and with the vertices of the square as A, B, C and D, the diagonally opposite vertex A and vertex C were overlaid.
  • Vertex A was set on the horizontal plane and vertex C was laid over vertex A.
  • point E the point where vertex C separated from the measuring sample surface, was designated as point E, and the distance between point E and vertex C was defined as flexible value 1.
  • Flexible value 2 was measured by the same procedure but replacing Vertex A with vertex B and vertex C with vertex D.
  • the arithmetic mean value of flexible value 1 and flexible value 2 was recorded as the texture (stiffness) of the sample.
  • the average value of 10 samples is used as the texture (stiffness).
  • the average values for 5 samples measured with the fiber layer (A) of the artificial leather facing upward and 5 samples measured with the fiber layer (A) facing downward are used as the texture (stiffness).
  • the samples were visually and organoleptically evaluated by healthy adult males and females (10 each), for a total of 20 evaluators, and evaluated on a 7-level scale with the most frequent evaluation recorded as the luxuriant feel.
  • a luxuriant feel (fiber bundle dispersibility) of grade 4.0 to 7.0 is considered satisfactory (acceptable).
  • the average value for 10 samples was recorded as the luxuriant feel grade.
  • the adhesion rate of PU resin in the fiber sheet was measured by the following method.
  • the weight of the fiber sheet before PU resin impregnation is recorded as A (g).
  • the fiber sheet is impregnated with the PU resin dispersion, and then a pin tenter dryer is used for heated air drying at 130°C, after which it is immersed in hot water heated to 90°C for softening and then dried, to obtain a fiber sheet filled with the PU resin (hereunder also referred to as "resin-filled fiber sheet").
  • the weight of the resin-filled fiber sheet is designated as B (g).
  • the adhesion rate (C) of the PU resin is calculated by the following formula.
  • C B ⁇ A / A ⁇ 100 wt %
  • Measurement was performed using a laser diffraction particle size distribution analyzer ("LA-920" by Horiba, Ltd.) according to the manufacturer's instruction manual, and the median diameter was recorded as the mean primary particle size.
  • microparticles used may be "NL-05" by Mitsubishi Chemical Holdings Corp., and micronization of the hot water-soluble resin microparticles may be by the method described in Japanese Unexamined Patent Publication HEI No. 7-82384 .
  • Disturbance of the water stream discharged from the nozzle during water flow dispersion treatment was measured in the following manner.
  • the water stream discharged from the nozzle is photographed using a single-lens reflex camera ("D600” by Nikon Corp.) equipped with a telecentric lens ("S5LPJ007/212" by Sill Optics GmbH & Co. KG), and the image data is obtained.
  • the image data is loaded into a PC, the range of the water stream is cut off at 25 mm to 35 mm from the discharge hole of the nozzle hole, and the water stream diameter at every pixel row (about 6 ⁇ m) in the widthwise direction of the water stream is measured.
  • the mean diameter W of the water stream and the standard deviation ⁇ in a region from 25 mm to 35 mm from the discharge hole of the nozzle hole are calculated and the disturbance is calculated by the following formula.
  • Disturbance % ⁇ mm / W mm ⁇ 100
  • the average value for 5 values obtained from the image data is recorded as the disturbance.
  • a sea-island composite fiber with a mean fiber size of 18 ⁇ m was obtained with a composite ratio of 20 wt% sea-component and 80 wt% island-component, and 16 islands/1f.
  • the obtained sea-island composite fiber was cut to fiber lengths of 51 mm as cut fibers and passed through a card and cross lapper to form a fiber web, which was then needled-punched to obtain a fiber sheet.
  • the obtained fiber sheet was immersed in 95°C hot water for contraction and a pin tenter dryer was used for drying at 100°C for 5 minutes, to obtain a single-layer fiber sheet with a basis weight of 600 g/m 2.
  • the obtained fiber sheet was immersed in a 10 g/L sodium hydroxide aqueous solution that had been heated to 95°C for 25 minutes of treatment, to dissolve the sea-component of the sea-island composite fibers.
  • the single fiber mean diameter of the fibers composing the fiber sheet after sea-component dissolutiondis solution was 4 ⁇ m.
  • a high-speed water stream was sprayed several times at a pressure of 4 MPa from the upper layer side and 3 MPa from the lower layer side using a 3-row straight flow injection nozzle with a nozzle hole interval of 0.25 mm, a disturbance of 17% and a hole diameter of 0.10 mm, to promote formation of single fibers for the fibers of the fiber bundles.
  • the fiber sheet was then impregnated with an impregnating liquid comprising the polyether-based water-dispersed PU dispersion "AE-12" (product of Nicca Chemical Co., Ltd.) (solid concentration: 35 wt%) having a mean primary particle size of 0.3 ⁇ m in an amount of 9.0% (as solid wt%) in the impregnating liquid, anhydrous sodium sulfate as an auxiliary agent in an amount of 3.0 wt% (as solid wt%) in the impregnating liquid, and the PVA resin fine particles "NL-05" (product of Mitsubishi Chemical Holdings Corp.) with a mean particle diameter of 3 ⁇ m, and then moist heat coagulation was carried out at 100°C for 5 minutes, and a pin tenter dryer was used for hot air drying at 130°C to 150°C for 2 to 6 minutes.
  • an impregnating liquid comprising the polyether-based water-dispersed PU dispersion "AE-12" (product of Nicca Chemical Co., Ltd.
  • a half-cut machine with an endless band knife was then used for half-cutting of the sheet perpendicular to the thickness direction, and the non-half-cut side was subjected to buffing treatment using #400 emery paper, after which a jet dyeing machine was used for dyeing at 130°C for 15 minutes with a blue disperse dye stuff ("BlueFBL" by Sumitomo Chemical Co., Ltd.) at a 5.0% owf dyeing density, and reduction cleaning was carried out.
  • a pin tenter dryer was then used for drying at 100°C for 5 minutes to obtain single-layer artificial leather.
  • Example 1 The results for Examples 1 to 15 and Comparative Examples 1 to 6 are shown in Table 1.
  • Table 1 Conditions Results Water flow dispersion treatment after sea-component dissolution PVA microparticles Proportion of PU resin in fiber sheet K-nearest neighbor distance ratio Cross-sectional PU area ratio Space size Stiffness Luxuriant feel Carried out Disturbance Water pressure Hole diameter Interval Number of rows Added Diameter Area ratio Standard deviation [%] [MPa] [mm] [mm] [ ⁇ m] [wt%] [%] [%] [%] [%] [ ⁇ m] [cm] [grade] Example 1 Yes 17 4 0.1 0.25 3 Yes 3 30 44 21 13 8 18 7 Example 2 Yes 13 4 0.1 0.25 3 Yes 3 30 51 20 13 8 18 7 Example 3 Yes 11 4 0.1 0.25 3 Yes 3 30 53 20 15 9 20 6 Example 4 Yes 7 4 0.1 0.25 3 Yes 3 30 65 19 18 10 21 6 Example 5 Yes 17 5.5 0.1 0.25 3 Yes 3 30 28 19 11 7 24 6 Example 6 Yes 17 12 0.1 0.
  • Example 2 Yes 17 4 0.1 0.25 3 No - 30 46 21 36 28 27 3 Comp.
  • Example 3 Yes 17 4 0.1 0.25 3 Yes 0.5 30 46 19 27 23 25 3 Comp.
  • Example 4 Yes 17 4 0.1 0.25 3 Yes 11 30 45 19 33 28 >28 5 Comp.
  • Example 5 Yes 17 4 0.1 0.25 3 Yes 3 14 45 9 23 38 11 2 Comp.
  • the cross-sectional PU resin area ratio for cross-sections in the thickness direction was 10% to 30%
  • the standard deviation of the cross-sectional PU resin area ratio was 25% or lower, and therefore the PU resin and single fibers were distributed in the specified manner and artificial leather exhibiting texture (stiffness), a luxuriant feel and a slick feel had been obtained.
  • the artificial leather of the invention has excellent texture (stiffness), and a luxuriant feel and slick feel, and can therefore be satisfactorily used as a sheet covering material or interior finishing material for interiors, automobiles, aircraft or railway vehicles, or in a clothing product.
  • the artificial leather of the invention can be suitably used as an interior finishing material with a very delicate outer appearance when used as a covering material for furniture, chairs, wall materials, or for seats, ceilings or interior finishings for vehicle interiors of automobiles, electric railcars or aircraft, or as a clothing material used in parts of shirts, jackets, uppers or trims for shoes including casual shoes, sports shoes, men's shoes or women's shoes, or bags, belts and wallets, or as industrial materials such as wiping cloths, abrasive cloths or CD curtains.

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  • Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)
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JPH0655999B2 (ja) * 1985-09-10 1994-07-27 旭化成工業株式会社 スエ−ド調人工皮革の製造方法
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JP4506471B2 (ja) * 2004-01-14 2010-07-21 東レ株式会社 皮革様シート状物の製造方法
JP4563041B2 (ja) * 2004-01-27 2010-10-13 日華化学株式会社 多孔性構造体の製造方法、多孔性構造体及び皮革状構造物
JP4788551B2 (ja) * 2005-11-30 2011-10-05 東レ株式会社 皮革様シート状物、その製造方法、並びにそれを用いてなる内装材、衣料用資材及び工業用資材
JP2010248683A (ja) * 2009-03-26 2010-11-04 Toray Ind Inc 皮革様シート状物およびその製造方法
JP6022161B2 (ja) 2011-03-23 2016-11-09 株式会社クラレ 人工皮革用基材
JP2014025165A (ja) 2012-07-26 2014-02-06 Toray Ind Inc シート状物の製造方法
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JP6551227B2 (ja) 2014-02-27 2019-07-31 東レ株式会社 シート状物およびその製造方法
JP6340827B2 (ja) 2014-02-27 2018-06-13 東レ株式会社 シート状物
KR101636476B1 (ko) 2014-05-12 2016-07-06 고려대학교 산학협력단 드론을 이용한 네트워크 서비스 제공 방법 및 그 장치
JP6613764B2 (ja) * 2014-09-30 2019-12-04 東レ株式会社 人工皮革およびその製造方法
KR101993736B1 (ko) 2015-07-14 2019-06-28 주식회사 엘지화학 위상차 필름, 이의 제조방법 및 이를 포함하는 액정 표시 장치
JP2017137588A (ja) * 2016-02-02 2017-08-10 旭化成株式会社 伸びを有する人工皮革
JP7322477B2 (ja) * 2018-04-09 2023-08-08 東レ株式会社 シート状物およびその製造方法
KR20210035276A (ko) * 2018-09-14 2021-03-31 아사히 가세이 가부시키가이샤 인공 피혁 및 그 제조 방법

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JP7282908B2 (ja) 2023-05-29
EP4053330A4 (fr) 2022-12-21
KR20220062099A (ko) 2022-05-13

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