Piled sheet and process for producing the same

Abstract

A raised sheet composed of three layers which are united by entanglement. The three layers are united in a layered structure of entangled nonwoven fabric A made of microfine fibers/polyurethane sheet B/woven or knitted fabric C or a layered structure of entangled nonwoven fabric A made of microfine fibers/woven or knitted fabric C/polyurethane sheet B. On the surface of the entangled nonwoven fabric A, raised naps of the microfine fibers are formed. A part of the microfine fibers constituting the entangled nonwoven fabric A penetrates through the polyurethane sheet B and the woven or knitted fabric C in this order, or penetrates through the woven or knitted fabric C and the polyurethane sheet B in this order. At least a part of the penetrated microfine fibers bonds to polyurethane which constitutes the polyurethane sheet B. The raised sheet is excellent in the shape stability, for example, it does not lose its shape even after a long term use. In addition, the raised sheet has a good surface abrasion resistance and a soft and high-quality hand.

1 . A raised sheet comprising three layers which are united by entanglement, the raised sheet satisfying the following requirements:
 (1) three layers are united in a layered structure of entangled nonwoven fabric A made of microfine fibers/polyurethane sheet B/woven or knitted fabric C or a layered structure of entangled nonwoven fabric A made of microfine fibers/woven or knitted fabric C/polyurethane sheet B;   (2) the entangled nonwoven fabric Ahas raised microfine fibers on its surface;   (3) a part of the microfine fibers constituting the entangled nonwoven fabric A penetrates through the polyurethane sheet B and the woven or knitted fabric C in this order, or penetrates through the woven or knitted fabric C and the polyurethane sheet B in this order; and   (4) at least a part of the penetrated microfine fibers bonds to polyurethane which constitutes the polyurethane sheet B.   
   
   
       2 . The raised sheet according to  claim 1 , wherein an entangled nonwoven fabric D is further united by entanglement to an outer surface of the woven or knitted fabric C or the polyurethane sheet B which is disposed on an outermost surface of the layered structure, and a part of the microfine fibers constituting the entangled nonwoven fabric A penetrates through the polyurethane sheet B and the woven or knitted fabric C and is entangled with the fibers constituting the entangled nonwoven fabric D. 
   
   
       3 . The raised sheet according to  claim 1 , wherein an entangled nonwoven fabric D is further united by entanglement to an outer surface of the woven or knitted fabric C or the polyurethane sheet B which is disposed on an outermost surface of the layered structure; a part of the microfine fibers constituting the entangled nonwoven fabric A penetrates through the polyurethane sheet B and the woven or knitted fabric C and is entangled with the fibers constituting the entangled nonwoven fabric D; and a part of the fibers constituting the entangled nonwoven fabric D penetrates through the polyurethane sheet B and the woven or knitted fabric C and is entangled with the microfine fibers constituting the entangled nonwoven fabric A. 
   
   
       4 . The raised sheet according to any one of  claims 1  to  3 , wherein the microfine fibers constituting the entangled nonwoven fabric A are produced by converting microfine fiber-forming fibers which comprises a water-soluble polymer and a sparingly water-soluble polymer to the microfine fibers. 
   
   
       5 . A covering fabric for vehicle seats produced from the raised sheet as defined in any one of  claims 1  to  3 . 
   
   
       6 . A method of producing a raised sheet, which comprises:
 (1) a step of superposing a fiber web A′ made of microfine fiber-forming fibers, a polyurethane sheet B and a woven or knitted fabric C, thereby obtaining a superposed body having a layered structure of fiber web A′/polyurethane sheet B/woven or a layered structure of knitted fabric C or fiber web A′/woven or knitted fabric C/polyurethane sheet B;   (2) a step of entangling the superposed body such that at least a part of the microfine fiber-forming fibers penetrates through the polyurethane sheet B and the woven or knitted fabric C, thereby converting the fiber web A′ to an entangled nonwoven fabric A′ to unite the superposed body;   (3) a step of converting the microfine fiber-forming fibers to microfine fibers, thereby converting the entangled nonwoven fabric A″ to an entangled nonwoven fabric A; and   (4) a step of bonding at least a part of the microfine fibers penetrating through the polyurethane sheet B to polyurethane which constitutes the polyurethane sheet B by heat treatment, and then, forming raised microfine fibers on a surface of the entangled nonwoven fabric A; or   (5) a step of forming raised microfine fibers on a surface of the entangled nonwoven fabric A, and then, bonding at least a part of the microfine fibers penetrating through the polyurethane sheet B to polyurethane which constitutes the polyurethane sheet E by heat treatment.