Process for the production of paper

Abstract

The present invention relates to process for the production of paper from a suspension containing cellulosic fibers, and optional fillers, comprising adding to the suspension drainage and retention aids comprising a cationic organic polymer and anionic microparticulate material, forming and dewatering the suspension on a wire, wherein the cationic organic polymer has a non-aromatic hydrophobic group. The invention further relates to a cationic vinyl addition polymer comprising in polymerized form at least one non-cationic monomer having a non-aromatic hydrophobic group and at least one cationic monomer.

1 . A process for the production of paper from a suspension containing cellulosic fibres, and optional fillers, comprising adding to the suspension drainage and retention aids comprising a cationic organic polymer and anionic microparticulate material, forming and dewatering the suspension on a wire, characterised in that the cationic organic polymer has a non-aromatic hydrophobic group.  
     
     
         2 . A process according to  claim 1 , characterised in that the cationic organic polymer is a vinyl addition polymer comprising in polymerized form one or more monomers comprising at least one cationic monomer having a non-aromatic hydrophobic group.  
     
     
         3 . A process according to  claim 1  or  2 , characterised in that the cationic organic polymer is a vinyl addition polymer comprising in polymerized form at least one non-cationic monomer having a non-aromatic hydrophobic group and at least one cationic monomer.  
     
     
         4 . A process according to  claim 1 ,  2  or  3 , characterised in that the hydrophobic group is attached to a nitrogen or oxygen which, in turn, is attached to the polymer backbone via a chain of atoms.  
     
     
         5 . A process according to  claim 1 ,  2 ,  3  or  4 , characterised in that the hydrophobic group is an alkyl group containing from 3 to 12 carbon atoms.  
     
     
         6 . A process according to any of the preceding claims, characterised in that the cationic organic polymer is an acrylamide-based polymer.  
     
     
         7 . A process according to any of the preceding claims, characterised in that the cationic organic polymer comprises in polymerized form a cationic monomer having a non-aromatic hydrophobic group represented by the general formula (I):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; R 2  and R 3  are each an alkyl group having from 1 to 2 carbon atoms; A is O or NH; B is an alkylene group of from 2 to 8 carbon atoms or a hydroxy propylene group; R 4  is a substituent containing an alkyl group containing from 4 to 8 carbon atoms; and X −  is an anionic counterion.  
     
     
         8 . A process according to any of the preceding claims, characterised in that the cationic organic polymer comprises in polymerized form a non-ionic monomer having a non-aromatic hydrophobic group represented by the general formula (IV):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; A is O or NH; B is an alkylene group of from 2 to 8 carbon atoms or a hydroxy propylene group or, alternatively, A and B are both nothing whereby there is a single bond between C and N (O═C—NR 8 R 9 ); R 8  and R 9  are each H or a substituent containing an alkyl group having from 1 to 6 carbon atoms, at least one of R 8  and R 9  being a substituent containing an alkyl group having from 2 to 6 carbon atoms.  
     
     
         9 . A process according to any of the preceding claims, characterised in that the cationic organic polymer comprises in polymerized form a non-ionic monomer having a non-aromatic hydrophobic group represented by the general formula (V):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; A is O; B is an alkylene group of from 2 to 4 carbon atoms; n is an integer of at least 1; R 10  is alkyl having at least 2 carbon atoms.  
     
     
         10 . A process according to any of the preceding claims, characterised in that the cationic organic polymer is a vinyl addition polymer prepared from a monomer mixture comprising from 5 to 25 mole % of monomer having a non-aromatic hydrophobic group, and from 95 to 75 mole % of other copolymerizable monomers.  
     
     
         11 . A process according to any of the preceding claims, characterised in that the anionic microparticulate material is selected from silica-based particles and bentonite.  
     
     
         12 . A process according to any of the preceding claims, characterised in that the drainage and retention aids further comprises a low molecular weight cationic organic polymer.  
     
     
         13 . A process according to any of the preceding claims, characterised in that the suspension that is dewatered on the wire has a conductivity of at least 2.0 mS/cm.  
     
     
         14 . A process according to any of the preceding claims, characterised in that the process further comprises dewatering the suspension on a wire to obtain a wet web of paper and white water, recirculating the white water and optionally introducing fresh water to form a suspension containing cellulosic fibres, and optional fillers, to be dewatered, wherein the amount of fresh water introduced is less than 30 tons per ton of dry paper produced.  
     
     
         15 . A process according to any of the preceding claims, characterised in that less than 10 tons of fresh water is introduced into the process per ton of dry paper produced.  
     
     
         16 . A cationic vinyl addition polymer comprising in polymerized form at least one non-cationic monomer having a non-aromatic hydrophobic group and at least one cationic monomer.  
     
     
         17 . A cationic vinyl addition polymer according to  claim 16 , characterised in that the hydrophobic group is attached to a nitrogen or oxygen which, in turn, is attached to the polymer backbone via a chain of atoms.  
     
     
         18 . A cationic vinyl addition polymer according to  claim 16  or  17 , characterised in that the hydrophobic group is an alkyl group containing from 3 to 12 carbon atoms.  
     
     
         19 . A cationic vinyl addition polymer according to  claim 16 ,  17  or  18 , characterised in that the cationic vinyl addition polymer is an acrylamide-based polymer.  
     
     
         20 . A cationic vinyl addition polymer according to  claim 16 ,  17 ,  18  or  19 , characterised in that the cationic vinyl addition polymer comprises in polymerized form a non-ionic monomer having a non-aromatic hydrophobic group represented by the general formula (IV):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; A is O or NH; B is an alkylene group of from 2 to 8 carbon atoms or a hydroxy propylene group or, alternatively, A and B are both nothing whereby there is a single bond between C and N (O═C—NR 8 R 9 ); R 8  and R 9  are each H or a substituent containing an alkyl group having from 1 to 6 carbon atoms, at least one of R 8  and R 9  being a substituent containing an alkyl group having from 2 to 6 carbon atoms.  
     
     
         21 . A cationic vinyl addition polymer according to any of  claims 16  to  20 , characterised in that the cationic vinyl addition polymer comprises in polymerized form a non-ionic monomer having a non-aromatic hydrophobic group represented by the general formula (V):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; A is O or NH; B is an alkylene group of from 2 to 4 carbon atoms; n is an integer of at least 1; R 10  is alkyl having at least 2 carbon atoms.  
     
     
         22 . A cationic vinyl addition polymer according to any of  claims 16  to  21 , characterised in that the cationic vinyl addition polymer comprises in polymerized form a cationic monomer represented by the general formula (I):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; R 2  and R 3  are each H or an alkyl group having from 1 to 3 carbon atoms; A is O or NH; B is an alkylene group of from 2 to 4 carbon atoms or a hydroxy propylene group; R 4  is a non-aromatic hydrocarbon group containing from 4 to 8 carbon atoms; and X −  is an anionic counterion.  
     
     
         23 . A cationic vinyl addition polymer according to any of  claims 16  to  22 , characterised in that the cationic vinyl addition polymer comprises in polymerized form a cationic monomer represented by the general formula (III):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is H or CH 3 ; R 2  and R 3  are each H or an alkyl group having from 1 to 3 carbon atoms, suitably 1 to 2 carbon atoms; A is O or NH; B is an alkylene group of from 2 to 8 carbon atoms, suitably 2 to 4 carbon atoms, or a hydroxy propylene group; R 7  is H, an alkyl group having from 1 to 3 carbon atoms, a benzyl group or a phenylethyl group; and X −  is an anionic counterion.  
     
     
         24 . A cationic vinyl addition polymer according to any of  claims 16  to  23 , characterised in that the cationic vinyl addition polymer is prepared from a monomer mixture comprising from 5 to 25 mole % of non-ionic monomer having a non-aromatic hydrophobic group, and from 95 to 75 mole % of other copolymerizable monomers.