Amphoteric cationic polymers for controlling deposition of pitch and stickies in papermaking

Abstract

The present invention relates to a method and composition for controlling pitch and stickies deposit in a pulp and papermaking process using amphoteric copolymers of diallyldimethylammonium chloride (DADMAC) with acrylic acid and/or acrylamide and optionally a siliceous material.

1 . A method of controlling pitch and stickies deposition in papermaking which method comprises the step of adding to paper furnish prior to sheet formation a composition comprising an amphoteric polymer represented by the following structure (I)  
       
         
           
           
               
               
           
         
       
       wherein X −  is an anion; 
 M +  is hydrogen, ammonium, sodium, or potassium;  
 R is hydrogen or methyl;  
 R 1  is methyl or ethyl;  
 n is from about 70 to about 99.8 wt. %, m is from about 0.2 to about 30%  
 and  
 p is from 0 to about 30%,  
 with n+m+p=100% based on the total weight of the amphoteric polymer.  
 
     
     
         2 . A method according to  claim 1 , 
 wherein X −  is Cl − ,    M +  is Na + ,    n is from about 85 to about 98%,    m is from about 1 to about 15%,    and p is from 0 to about 10% by weight.    
     
     
         3 . A method according to  claim 1  further comprising the step of adding a siliceous material.  
     
     
         4 . A method according to  claim 3  wherein the amphoteric polymer is added to the paper furnish followed by addition of the siliceous material.  
     
     
         5 . A method according to  claim 3  wherein the siliceous material is added to the paper furnish followed by addition of the amphoteric polymer.  
     
     
         6 . A method according to  claim 3 , wherein the siliceous material is an anionic microparticulate material.  
     
     
         7 . A method according to  claim 3 , wherein the siliceous material comprises material selected from the group consisting of silica based particles, silica microgel, colloidal silica, silica sols, silica gels, polysilicates, cationic silica, aluminosilicates, polyaluminosilicates, borosilicates, polyborosilicates and zeolites.  
     
     
         8 . A process according to  claim 3  wherein the siliceous material is a swellable clay.  
     
     
         9 . A process according to  claim 8  wherein the swellable clay is selected from the group consisting of hectorite, smectitites, montmorillonites, nontronites, saponite, sauconite, hormites, attapulgites, and sepiolites.  
     
     
         10 . A method according to  claim 2 , wherein m is from about 1 to about 8%.  
     
     
         11 . A method according to  claim 1 , wherein p is from about 1 to about 8%.  
     
     
         12 . A method according to  claim 1 , wherein the amphoteric polymer has a molar ratio of n/m of about 1.2 or greater.  
     
     
         13 . A method according to  claim 12 , wherein the molar ratio of n/m is about 4 or greater.  
     
     
         14 . A method according to  claim 1 ,  
       wherein 
 n represents a unit derived from a cationic monomer selected from the group consisting of diallyldialkylammonium compounds;  
 m represents a unit derived from an anionic monomer or potentially anionic monomer selected from the group consisting of hydrolysed acrylamide, hydrolysed methacrylamide, acrylic acid, methacrylic acid and/or salts of acrylic acid or methacrylic acid.  
 
     
     
         15 . A method according to  claim 14 , wherein the anionic monomer is hydrolysed acrylamide.  
     
     
         16 . A method according to  claim 14 , wherein the anionic monomer is acrylic acid, methacrylic acid and/or salts thereof.  
     
     
         17 . A method according to  claim 14 , wherein the cationic monomer is diallyldiethylammonium halide or diallydimethylammonomium halide.  
     
     
         18 . A method according to  claim 1 , wherein the amphoteric polymer of formula (I) has a weight average molecular weight ranging from about 10,000 to about 20,000,000.  
     
     
         19 . A method according to  claim 1 , wherein the paper furnish contains thermal mechanical pulp, recycled pulp, coated broke, deinked pulp or mixtures thereof.  
     
     
         20 . A composition for pitch and stickies control in papermaking comprising a structure (I) according to  claim 1  and optionally, a siliceous material.