Ultrafine fiber entangled sheet and method of producing the same

A method of producing an entangled non-woven fabric including a portion (A) comprised of ultrafine fiber bundles entangled with one another and a portion (B), said portion (B) comprising either ultrafine fibers of fine bundles of ultrafine fibers or both, branching from said ultrafine fiber bundles and entangled with one another;

• said method comprising the steps of:
• (1) forming a fiber entangled sheet by use of fibers comprising an ultrafine fiber component and a bonding component which bonds said ultrafine fiber components, arranged in the longitudinal direction of the fibers in an arbitrary cross-section, said components being polymer materials having a different solvent solubility from each other;
• (2) dissolving and removing said binding component by use of a solvent which can dissolve said binding component but not said fiber components, and
• (3) applying a high speed fluid jet stream to said fibers so as to branch and entangle said fibers and to produce a degree of branching continuously along the boundary portion between both portions (A) and (B).

A method of producing an entangled non-woven fabric including a portion (A) comprised of ultrafine fiber bundles entangled with one another and a portion (B) comprised of ultrafine fibers or fine bundles of ultrafine fiber bundles or both, and entangled with one another, said method comprising the steps of:

• (1) forming a fiber sheet by use of fibers comprising an ultrafine fiber component and a bonding component which bonds said ultrafine fiber component, arranged in the longitudinal direction of the fibers in an arbitrary cross-section, said components being polymer materials having a different solvent solubility from each other;
• (2) applying high speed fluid jet streams so as to branch and entangle said branched fibers;
• and
• (3) dissolving and removing said binding component by use of a solvent which can dissolve said binding components but cannot dissolve said fibers, thus producing a degree of branching changing continuously along the boundary portion between both portions (A) and (B).

A method of producing a grained sheet having on at least one of its surfaces a grain formed by a fiber structure composed of ultrafine fibers or fine bundles of said ultrafine fibers or both and having a distance between the fiber entangling points of not greater than about 200 microns, and a resin present in the gap portions of said fiber structure, said method comprising the steps of:

• (1) forming a fiber sheet using fibers selected from ultrafine fiber formable fibers and ultrafine fibers;
• (2) applying a high speed fluid jet stream to said fiber sheet to branch and entangle said fibers;
• (3) applying at least one kind of resin on at least one of its surfaces;
• and
• (4) embossing or pressing said applied surface to form a grain.