Aqueous surface-coating agent for paper and paperboard

Abstract

The present invention relates to an aqueous surface coating composition for paper and board with a solids content of 1 to 55 wt % comprising (A) 0 to 20 parts by weight of starch (solids), (B) 0.01 to 20 parts by weight of a zirconium carbonate compound, (C) 0.01 to 40 parts by weight of water-soluble synthetic polymer (solids) containing in copolymerized form one or more monomers having monoethylenic double bonds, and also to a method for producing paper and board using the aqueous surface coating composition, and to corrugated boards produced from this paper.

1 . An aqueous surface coating composition for paper and board with a solids content of 1 to 55 wt %, the coating composition comprising:
 (A) 0 to 20 parts by weight of a starch;   (B) 0.01 to 20 parts by weight of a zirconium carbonate compound; and   (C) 0.01 to 40 parts by weight of a water-soluble synthetic polymer comprising in copolymerized form at least one monomer comprising at least one monoethylenic double bond.   
     
     
         2 . The aqueous surface coating composition according to  claim 1 , wherein the water-soluble synthetic polymer has an average molecular weight M w ≤1 million daltons. 
     
     
         3 . The aqueous surface coating composition according to  claim 1 , wherein the water-soluble synthetic polymer comprises at least one monomer in copolymerized form selected from the group consisting of an acrylamide, a vinyl alcohol, a vinyl acetate, and an N-vinylcarboxamide of the formula (I): 
       
         
           
           
               
               
           
         
       
       in which R 1 , R 2 ═H or C 1  to C 6  alkyl. 
     
     
         4 . The aqueous surface coating composition according to  claim 1 , wherein the water-soluble synthetic polymer is an anionic polymer. 
     
     
         5 . The aqueous surface coating composition according to  claim 1 , wherein the water-soluble synthetic polymer is obtainable by copolymerizing a monomer mixture comprising:
 (a) at least one monomer selected from the group consisting of an acrylamide and an N-vinylcarboxamide of the formula (I):   
       
         
           
           
               
               
           
         
       
       in which R 1 , R 2 ═H or C 1  to C 6  alkyl;
 (b) at least one monoethylenically unsaturated monomer comprising an acid group, an alkali metal salt of an acid group, an alkaline earth metal salt of an acid group, and an ammonium salt of an acid group, or a mixture thereof; 
 (c) optionally at least one monoethylenically unsaturated monomer which is different from the monomers (a) and (b); and 
 (d) optionally at least one compound having at least two ethylenically unsaturated double bonds in the molecule. 
 
     
     
         6 . The aqueous surface coating composition according to  claim 1 , wherein the water-soluble synthetic polymer is a copolymer or terpolymer comprising in copolymerized form monomers acrylic acid and vinylformamide. 
     
     
         7 . The aqueous surface coating composition according to  claim 1 , wherein the aqueous surface coating composition has a viscosity in the range from 1 to 200 mPa·s. 
     
     
         8 . The aqueous surface coating composition according to  claim 1 , comprising:
 (A) 1 to 20 parts by weight of the starch;   (B) 0.01 to 20 parts by weight of the zirconium carbonate compound; and   (C) 0.01 to 40 parts by weight of the water-soluble synthetic polymer.   
     
     
         9 . A method for producing paper and board, the method comprising:
 a) treating a paper stock with a paper auxiliary, a filler, or both, to obtain a treated paper stock;   b) draining the treated paper stock with sheet formation, to obtain a paper web; and   c) coating the paper web with the surface coating composition of  claim 1 , to obtain a coated paper web; and   d) drying the coated paper web.   
     
     
         10 . A paper or board obtained by the method according to  claim 9 . 
     
     
         11 . A method for producing corrugated board, the method comprising corrugating the board of  claim 10  to obtain a corrugated board. 
     
     
         12 . A corrugated board obtained by the method of  claim 11 .