Electrophotographic recording sheet and label paper

Abstract

Provided are an electrophotographic recording sheet, which has an electrostatic capacity of greater than or equal to 4 pF/cm 2 and a Clark stiffness of from 15 to 500, and which comprises a thermoplastic resin sheet (A) that is formed by stretching along at least one axis and heat treating at 50 to 250° C.; and a label paper in the form of a laminate sequentially having an adhesive layer (B) and a release paper (C) on one surface of the thermoplastic resin sheet (A), wherein, under a thermomechanical analysis with heating from room temperature to 150° C., a dimensional change ratio (α) of the thermoplastic resin sheet (A) after heating to the unheated thermoplastic resin sheet (A) is from −2.5 to 2.5 percent and the difference (α−β) is from −1.5 to 1.5 percent, where β is a dimensional change ratio of the release paper (C) after heating to the unheated release paper (C). The electrophotographic recording sheet and label paper of the present invention have good water repellency, good durability, are suited to electrophotographic printing, and thus can be employed in a wide range of applications.

What is claimed is:  
     
         1 . An electrophotographic recording sheet having an electrostatic capacity of greater than or equal to 4 pF/cm 2  and a Clark stiffness of from 15 to 500, wherein the electrophotographic recording sheet comprises a thermoplastic resin sheet (A) that is formed by stretching along at least one axis and heat treating at 50 to 250° C.  
     
     
         2 . The electrophotographic recording sheet according to  claim 1 , wherein the thermoplastic resin sheet (A) comprises an electrostatic capacity modifier.  
     
     
         3 . The electrophotographic recording sheet according to  claim 1 , wherein 
 the thermoplastic resin sheet (A) comprises 
 a thermoplastic resin, and  
 1 to 190 weight parts of finepowder per 100 weight parts of the thermoplastic resin; and  
   the finepowder comprises at least one of inorganic finepowder and organic finepowder.    
     
     
         4 . The electrophotographic recording sheet according to  claim 1 , wherein a void rate of the thermoplastic resin sheet (A) is in a range of from 0 to 60 percent.  
     
     
         5 . The electrophotographic recording sheet according to  claim 1 , wherein the thermoplastic resin sheet (A) has a whiteness degree according to JIS L1015 of 85 percent or more and a opacity according to JIS P8138 of 50 percent or more.  
     
     
         6 . The electrophotographic recording sheet according to  claim 1 , wherein 
 the thermoplastic resin sheet (A) comprises a thermoplastic resin; and    the thermoplastic resin comprises an olefin resin.    
     
     
         7 . The electrophotographic recording sheet according to  claim 6 , wherein the olefin resin comprises propylene based resin.  
     
     
         8 . A recorded product obtained by printing the electrophotographic recording sheet of  claim 1  by an electrophotographic method.  
     
     
         9 . A method of making an electrophotographic recording sheet, the method comprising 
 stretching and heating a sheet comprising a thermoplastic resin; and    producing the electrophotographic recording sheet of  claim 1 .    
     
     
         10 . A method of using an electrophotographic recording sheet, the method comprising printing on the electrophotographic recording sheet of  claim 1 .  
     
     
         11 . A label paper comprising, sequentially, 
 a thermoplastic resin sheet (A) that is formed by stretching along at least one axis and heat treating at 50 to 250° C.;    an adhesive layer (B); and    a release paper (C), wherein 
 under a thermomechanical analysis with heating from room temperature to 150° C., 
 α is in a range of from −2.5 to 2.5 percent; and  
 α−β is in a range of from −1.5 to 1.5 percent, where 
 α is a ratio of a dimension of the thermoplastic resin sheet (A) after the heating to the dimension of the thermoplastic resin sheet (A) before the heating; and  
 β is a ratio of a dimension of the release paper (C) after the heating to the dimension of the release paper (C) before the heating.  
 
 
   
     
     
         12 . The label paper according to  claim 11 , wherein an electrostatic capacitance of the label paper is greater than or equal to 4 pF/cm 2 .  
     
     
         13 . The label paper according to  claim 11 , wherein, when printing on A-4 size (210×297 mm) label paper with an electrophotographic printer, an average of four corner curl heights two minutes after printing is less than or equal to 100 mm.  
     
     
         14 . A recorded product obtained by printing the label paper of  claim 11  by an electrophotographic method.  
     
     
         15 . A method of making a label paper, the method comprising 
 laminating a thermoplastic resin sheet, an adhesive layer, and a release paper; and    producing the label paper of  claim 11 .    
     
     
         16 . A method of using a label paper, the method comprising printing on the label paper of  claim 11.