Kuraray Co., Ltd.

Yoshiyuki Ando

Jiro Tanaka

Michinori Fujisawa

Norio Makiyama

Yoshiki Nobuto

Tsuyoshi Yamasaki

Kimio Nakayama

Masaru Makimura

Yoshiaki Yasuda

Yoshihiro Tanba

Yasunori Murate

Hidekazu Andoh

Yasuhiro Takeda

Yoshikata Ohno

A substrate for artificial leather comprising a nonwoven fabric of bundles of microfine filaments. The substrate for artificial leather simultaneously satisfies the following requirements 1 to 4: (1) the bundle of microfine filaments comprises 8 to 70 microfine filaments having a cross-sectional shape of nearly circle; (2) the bundle of microfine filaments has a cross-sectional area of 170 to 700 &#x3bc;mand a flatness of 4.0 or less; (3) on a cross section parallel to a thickness direction of the nonwoven fabric body, cross sections of the microfine fiber bundles exist in a density of 1500 to 3000/mm; and (4) on a cross section parallel to a thickness direction of the nonwoven fabric body, gaps between the microfine fiber bundles have a size of 70 &#x3bc;m or less. By satisfying the requirements, the substrate for artificial leather combines high level of sensuous qualities and high level of physical properties which have been considered to be mutually exclusive.

Base material for artificial leather and process for producing the same

A leather-like sheet containing a microfine long-fiber nonwoven fabric containing an entangled web structure made of bundles of microfine long fibers and an elastic polymer impregnated in the microfine long-fiber nonwoven fabric. The leather-like sheet has a machine direction/transverse direction ratio of breaking strength of 1/1 to 1.3/1, an elongation at break in each of the machine direction and the transverse direction of 80% or more, and a machine direction/transverse direction ratio of elongation at break of 1/1 to 1/1.5. The leather-like sheet has a natural dense feeling, a soft hand, a small difference of mechanical properties in the machine direction and the transverse direction, a moderate resistance to elongation and a durable recovery.

Leather-like sheet and process for producing the same

A (semi)grain-finished leather-like sheet composed of an entangled nonwoven fabric of three-dimensionally entangled fiber bundles containing microfine long fibers and an elastic polymer contained in the entangled nonwoven fabric. When dividing the (semi)grain-finished leather-like sheet to five layers with equal thickness, i.e., surface layer, substrate layer, substrate layer, substrate layerand back layer in this order along the thickness direction, part of the microfine long fibers forming the surface layer and/or the back layer are fuse-bonded to each other and the microfine long fibers forming the intermediate layer are not fuse-bonded. With such a fuse-bonding state of the microfine long fibers, the (semi)grain-finished leather-like sheet combines a low compression resistance and a dense feel each comparable to natural leathers, has a sufficient practical strength, and are excellent in properties which are required according to its use.

Leather-like sheet bearing grain finish and process for producing the same

A method of producing a substrate suitable for artificial leathers. The substrate is composed of an entangled nonwoven fabric made of microfine fibers and a binder resin. At least one surface of the substrate is a densified layer which is made of the microfine fibers and which is substantially free from the binder resin. The binder resin is impregnated into a portion of the substrate other than the densified layer. The densified layer prevents the binder resin impregnated into the entangled nonwoven fabric from migrating into the surface of the entangled nonwoven fabric, thereby providing the substrate having the surface substantially free from the binder resin. The peeling strength between the substrate and a grain layer formed on the surface thereof is drastically improved because the surface of the substrate is substantially free from the binder resin.

Base material for artificial leather and grained artificial leather

A method of producing an entangled sheet of microfine long fibers using long fibers for forming microfine fibers. The method includes a step of forming a long-fiber web made of long fibers for forming microfine fibers, at least one component of the long fibers being a water-soluble, thermoplastic polyvinyl alcohol resin; a step of entangling the long-fiber web to form a long-fiber entangled sheet; a step of shrinking the long-fiber entangled sheet to form a long-fiber shrunk sheet; and a step of converting the long fibers for forming microfine fibers in the long-fiber shrunk sheet to microfine long fibers, thereby producing the entangled sheet of microfine long fibers. The step of entangling is conducted so as to allow the long-fiber entangled sheet to have an interlaminar peel strength of 2 kg/2.5 cm or more. The step of shrinking is conducted so as to shrink in an areal shrinkage of 35% or more.

Process for producing intertwined ultrafine filament sheet

A substrate for artificial leathers which is composed of a nonwoven fabric made of fiber bundles of microfine fibers having an average single fiber fineness of 0.5 dtex or less and an elastic polymer impregnated into the nonwoven fabric. The substrate for artificial leathers satisfies the following requirements 1 and 2: (1) the number of fiber bundles which are oriented to a thickness direction of the nonwoven fabric is 75 to 300 per 1 cm of width which is perpendicular to the thickness direction, when measured on a cross section parallel to the thickness direction; and (2) the number of cross sections of the fiber bundles which are oriented to the thickness direction is 30 to 800 per 1 mm, when measured on a cross section perpendicular to the thickness direction. The substrate for artificial leathers is suitable for the production of a grain-finished artificial leather which combines a non-repulsive softness and firm hand resembling natural sheep leathers and has fine buckling wrinkles, and a suede-finished or nubuck artificial leather having a surface touch with fine texture and a grace writing effect each being hitherto not obtained.

Base material for artificial leathers and method of producing the same

A substrate for artificial leathers, comprising a nonwoven fabric body made of microfine fiber bundles and an elastic polymer impregnated therein. The substrate for artificial leathers simultaneously satisfies the following requirements 1 to 4: (1) each of the microfine fiber bundles contains 6 to 150 bundled microfine long fibers in average; (2) a cross-sectional area of the microfine long fibers constituting the microfine fiber bundles is 27 &#x3bc;mor less, and 80% or more of the microfine long fibers has a cross-sectional area of from 0.9 to 25 &#x3bc;m; (3) an average cross-sectional area of the microfine fiber bundles is from 15 to 150 &#x3bc;m; and (4) on a cross section parallel to a thickness direction of the nonwoven fabric body, cross sections of the microfine fiber bundles exist in a density of from 1000 to 3000/mmin average. The raised artificial leathers and grain-finished artificial leathers made from the substrate for artificial leathers are excellent in the properties which are hitherto difficult to be combined.

Base for synthetic leather and synthetic leathers made by using the same

A composite staple fiber, wherein a polymer component A and a polymer component B are alternately arranged in a fiber horizontal cross-section; the fiber periphery is entirely covered with the polymer component A; both the polymer component A and the polymer component A have a substantially flat shape; the lengthwise ends of the polymer component B are located 0.05 to 1.5 &mgr;m from the fiber surface; and the weight ratio of the polymer component A to the polymer component B is from 90/10 to 10/90. The composite staple fiber of the present invention is not peeled or split by a carding and a needle punching treatments, but is divided and split in the subsequent water jet entanglement, resulting in flat ultrafine fibers having a sharp-edged structure.

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Okayama, Japan

Yoshiyuki Ando