Recording paper

Abstract

The invention relates to a recording paper comprising a sheet core layer mainly comprising a recycled pulp, and having multiplied on both sides of said sheet core layer, at least one sheet surface layer mainly comprising a bleached chemical pulp.

1 . A recording paper comprising a sheet core layer mainly comprising a recycled pulp, and having multiplied on both sides of said sheet core layer, at least one sheet surface layer mainly comprising a bleached chemical pulp.  
     
     
         2 . The recording paper according to  claim 1 , wherein said at least one sheet surface layer on either one of the both sides has a thickness that gives a ratio of 0.4 to 4.0 relative to the thickness of the sheet core layer.  
     
     
         3 . The recording paper according to  claim 1 , wherein said bleached chemical pulp in said sheet surface layer is one obtained by a kraft digester process.  
     
     
         4 . The recording paper according to  claim 1 , wherein said bleached chemical pulp in said sheet surface layer has a whiteness of 85% or higher.  
     
     
         5 . The recording paper according to  claim 4 , wherein the whiteness of said bleached chemical pulp is 90% or higher.  
     
     
         6 . The recording paper according to  claim 1 , wherein at least one of said sheet surface layers further comprises at least one of a sizing agent and a paper strength-enhancer.  
     
     
         7 . The recording paper according to  claim 1 , further having, on at least one side thereof, a porous ink-receiving layer containing a pigment.  
     
     
         8 . The recording paper according to  claim 7 , wherein the pigment contained in said porous ink-receiving layer comprises at least one of gas-phase-process silica and an alumina compound.  
     
     
         9 . The recording paper according to  claim 8 , wherein said gas-phase-process silica has an average primary particle diameter of 3 to 50 nm.  
     
     
         10 . The recording paper according to  claim 8 , wherein said alumina compound is alumina hydrate of a tabular shape having an average aspect ratio of 3 to 8.  
     
     
         11 . The recording paper according to  claim 8 , wherein said alumina compound is γ-form aluminum oxide ultrafine particles having an average primary particle diameter of less than 80 nm.  
     
     
         12 . The recording paper according to  claim 7 , wherein said porous ink-receiving layer contains the pigment in an amount of 40 to 90% by weight based on the total weight of solid matter therein.  
     
     
         13 . The recording paper according to  claim 7 , wherein said porous ink-receiving layer further comprises a binder in an amount of 2 to 50% by weight based on the weight of said pigment.  
     
     
         14 . The recording paper according to  claim 7 , wherein said porous ink-receiving layer further comprises a cationic substance.  
     
     
         15 . The recording paper according to  claim 14 , wherein said cationic substance is a polymer having a quaternary ammonium salt group.  
     
     
         16 . The recording paper according to  claim 14 , wherein said porous ink-receiving layer contains said cationic substance in an amount of 0.5 to 15% by weight based on the total weight of solid matter therein.  
     
     
         17 . The recording paper according to  claim 7 , wherein said porous ink-receiving layer has a coating amount of 10 to 40 g/m 2  in terms of solid matter.  
     
     
         18 . The recording paper according to  claim 1 , further having, on at least one side thereof, an ink-receiving layer containing a water-soluble resin as a main component.