Sheet-like article, and method for producing same

Abstract

A sheet material includes a fibrous substrate made of microfibers and a hydrophilic-group-containing resin applied to the fibrous substrate. The hydrophilic-group-containing resin has a microphase-separated structure that satisfies Condition I: In a phase image obtained by observing an area of 1 μm 2 in a cross-section of the hydrophilic-group-containing resin applied to the fibrous substrate by phase imaging using an atomic force microscope (AFM), a standard deviation of a mode of brightness distribution of areas of 0.2 μm 2 in the area of 1 μm 2 is from 0 to 10. Provided are a sheet material that is produced through an eco-conscious production process and yet has such uniformity that is comparable to those of man-made leathers produced using organic-solvent-based polyurethanes, an elegant surface appearance, and a good touch, and a method for producing such a sheet material.

1 . A sheet material comprising:
 a fibrous substrate comprising microfibers; and   a hydrophilic-group-containing resin applied to the fibrous substrate, the hydrophilic-group-containing resin having a microphase-separated structure that satisfies Condition I:   I. In a phase image obtained by observing an area of 1 μm 2  in a cross-section of the hydrophilic-group-containing resin applied to the fibrous substrate by phase imaging using an atomic force microscope (AFM), a standard deviation of a mode of brightness distribution of areas of 0.2 μm 2  in the area of 1 μm 2  is from 0 to 10.   
     
     
         2 . A sheet material comprising:
 a fibrous substrate comprising microfibers; and   a hydrophilic-group-containing resin applied to the fibrous substrate, the hydrophilic-group-containing resin comprising an aromatic polyisocyanate, the hydrophilic-group-containing resin being a polyurethane resin crosslinked with a crosslinking agent.   
     
     
         3 . The sheet material according to  claim 2 , wherein the crosslinking agent is at least one of a polyisocyanate crosslinking agent and a carbodiimide crosslinking agent. 
     
     
         4 . The sheet material according to  claim 1 , wherein the hydrophilic-group-containing applied to the fibrous substrate is an aqueous dispersed type polyurethane resin. 
     
     
         5 . The sheet material according to any  claim 1 , wherein the fibrous substrate comprising microfibers is provided with an aqueous dispersed type polyurethane resin satisfying Conditions A to C:
 A. The aqueous dispersed type polyurethane resin, when in the form of a dry film, has a storage elastic modulus (E′) of 1 to 100 MPa;   B. The aqueous dispersed type polyurethane resin, when in the form of a dry film, has a loss elastic modulus (E″) of 0.1 to 20 MPa; and   C. The aqueous dispersed type polyurethane resin, when in the form of a dry film, has a tan δ of 0.01 to 0.30.   
     
     
         6 . A method for producing a sheet material, the method comprising:
 impregnating a dispersion into a fibrous substrate comprising microfibers, the dispersion comprising a crosslinking agent and an aqueous dispersed type polyurethane resin comprising an aromatic polyisocyanate; and   coagulating the dispersion.   
     
     
         7 . The method for producing a sheet material according to  claim 6 , wherein the crosslinking agent is at least one of a polyisocyanate crosslinking agent and a carbodiimide crosslinking agent. 
     
     
         8 . The method for producing a sheet material according to  claim 6 , further comprising heating the impregnated and coagulated dispersion at 80° C. to 200° C. after the dispersion is impregnated and coagulated. 
     
     
         9 . The method for producing a sheet material according to any one of  claim 6 , further comprising applying a highly saponified polyvinyl alcohol having a degree of saponification of 95% to 100% to the fibrous substrate comprising microfibers before the dispersion is impregnated and coagulated.