Printability improving agents and papers coated with them

Abstract

A printability improving agent for use in a neutral newsprint base paper which is printed with ecological inks, containing (I) a cationic copolymer obtained by polymerizing one or more hydrophobic monomer unit(s) selected from styrenes and alkyl acrylates and/or alkyl methacrylates with a quaternary ammonium salt-containing monomer unit, and (II) a copolymer obtained by polymerizing 100 parts by weight of one or more hydrophobic monomer(s) selected from the group above in the presence of 1-10 parts by weight of a surfactant.

1 .- 8 . (canceled) 
   
   
       9 . A method for improving offset printability of a neutral newsprint base paper which is printed with ecological inks, comprising applying to a surface of said neutral newsprint base paper a coating comprising one or more hydrophobic monomer(s) selected from the group consisting of (1) styrenes and (2) alkyl acrylates and/or alkyl methacrylates, in the presence of: a cationic copolymer obtained by polymerization of one or more hydrophobic monomer unit(s) selected from the group consisting of (1) styrenes and (2) alkyl acrylates and/or alkyl methacrylates and a quaternary ammonium salt-containing monomer unit; and a surfactant in amounts of 1-10 parts by weight based on 100 parts by weight of the hydrophobic monomer(s). 
   
   
       10 . The method of  claim 9  wherein the surface-treating agent comprises the printability improving agent and one or more water-soluble polymer material(s) selected from the group consisting of:
 (1) modified starches   (2) polyvinyl alcohols and   (3) cellulose derivatives.   
   
   
       11 . A paper produced by the process of  claim 9 . 
   
   
       12 . A paper produced by the process of  claim 10 . 
   
   
       13 . The paper of  claim 11  wherein the base paper is a newsprint base paper prepared by a neutral papermaking process. 
   
   
       14 . The paper of  claim 12  wherein the base paper is a newsprint base paper prepared by a neutral papermaking process.