Sheet material and method for producing same

Abstract

The purpose of the present invention is to provide: a sheet-like article which has a good balance between soft texture and excellent light resistance; and a method for producing this sheet-like article. In order to achieve this purpose, a sheet-like article according to the present invention has the following configuration. Specifically, a sheet-like article which contains a polymer elastic body in a fibrous base material, wherein: the fibrous base material is composed of ultrafine fibers that have an average single fiber diameter of from 0.1 μm to 10 μm; the polymer elastic body has a hydrophilic group, while containing a polyether diol as a constituent; the polymer elastic body internally has an N-acylurea bond and/or an isourea bond; and the condition 1 and the condition 2 described below are satisfied. Condition 1: The bending resistance in the lengthwise direction as determined in accordance with specific standards is from 40 mm to 140 mm. Condition 2: The abrasion weight loss after 20,000 cycles of a Martindale abrasion test set forth in JIS L 1096 (2005) after a light resistance test as performed under the conditions defined in accordance with specific standards is 25 mg or less.

1 . A sheet material comprising a polymer elastic body in a fibrous base material,
 wherein the fibrous base material includes ultrafine fibers having an average single fiber diameter of 0.1 μm or more and 10 μm or less, the polymer elastic body has a hydrophilic group and contains a polyether diol as a constituent, the polymer elastic body internally has an N-acylurea bond and/or an isourea bond, and the following condition 1 and condition 2 are satisfied:   condition 1: a bending resistance in a lengthwise direction as determined in accordance with Method A (45° cantilever method) set forth in JIS L 1096:2010 “Testing methods for woven and knitted fabrics” is 40 mm or more and 140 mm or less; and   condition 2: an abrasion weight loss after 20,000 cycles of a Martindale abrasion test set forth in JIS L 1096:2005 after a light resistance test as performed under the conditions that a xenon arc amount as measured by a light fastness measurement method of JIS L 0843:2006 is 110 MJ/m 2 , is 25 mg or less.   
     
     
         2 . The sheet material according to  claim 1 , wherein the abrasion weight loss after 20,000 cycles of the Martindale abrasion test set forth in JIS L 1096:2010 of the sheet material before the light resistance test is 20 mg or less. 
     
     
         3 . The sheet material according to  claim 1 , wherein the sheet material contains 10% by mass or more of the polymer elastic body. 
     
     
         4 . The sheet material according to  claim 1 , wherein
 the sheet material further satisfies the following condition 3:   condition 3: an L value retention when a napped surface of the sheet material is placed on a hot plate heated to 150° C. and pressed at a pressing load of 2.5 kPa for 10 seconds, is 90% or more and 100% or less.   
     
     
         5 . A method for producing a sheet material, comprising steps (1) to (4) shown below, in this order:
 (1) a polymer elastic body impregnating step of impregnating a fibrous base material including ultrafine fiber-generating fibers with an aqueous dispersion containing a polymer elastic body, a monovalent positive ion-including inorganic salt, and a crosslinker and then performing a heating treatment at a temperature of 120° C. or higher and 180° C. or lower, the polymer elastic body having a hydrophilic group and containing a polyether diol as a constituent, a content of the monovalent positive ion-including inorganic salt in the aqueous dispersion being 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer elastic body;   (2) an ultrafine fiber generating step of subjecting the ultrafine fiber-generating fibers to an alkali treatment to generate ultrafine fibers;   (3) a drying step of performing a thermal treatment at a temperature of 120° C. or higher and 180° C. or lower; and   (4) a nap raising step of subjecting at least one surface of an unnapped sheet material to a nap raising treatment to form a nap on the surface.   
     
     
         6 . The method for producing a sheet material according to  claim 5 , further comprising a dyeing step of dyeing the unnapped sheet material or the sheet material after the drying step. 
     
     
         7 . The method for producing a sheet material according to  claim 5 , wherein the monovalent positive ion-including inorganic salt is sodium chloride and/or sodium sulfate. 
     
     
         8 . The method for producing a sheet material according to  claim 5 , wherein the crosslinker is a carbodiimide-based crosslinker.