Method for Reducing Negative Effects of Natural Pitch Contaminants in Both Pulping and Papermaking Operations

Abstract

The instant invention relates to a method for inhibiting pitch deposition on pulping and papermaking equipment or machinery comprising adding to a pulp slurry containing pitch an effective amount of polymer dispersion comprising a component A and a component B, wherein component A being a homopolymer and/or copolymer of acrylic acid and/or its alkyl esters, or methacrylic acid and/or its alkyl esters, styrene and/or methylstyrene, vinyl acetate, itaconic acid, glycidyl methacrylate, 2-hydroxyalkyl (meth)acrylate, methacrylamide, N-hydroxyethyl(meth)acrylamide, dimethacrylate monomers, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, 4-methyl-1,4-pentanediol dimethacrylate, divinylbenzene and/or trivinylbenzene, and component B being an aqueous solution of a styrene copolymer with acrylic acid, maleimide and/or maleic anhydride.

1 . A method for inhibiting pitch deposition on pulping and/or papermaking equipment and/or machinery comprising adding to a pulp slurry containing pitch,. an effective amount of polymer dispersion comprising a component A and a component B, wherein component A being a homopolymer and/or copolymer of acrylic acid and/or one or more alkyl esters thereof, or methacrylic acid and/or one or more alkyl esters thereof, styrene and/or methylstyrene, vinyl acetate, itaconic acid, glycidyl methacrylate, 2-hydroxyalkyl (meth)acrylate, methacrylamide, N-hydroxyethyl(meth)acrylamide, dimethacrylate monomers, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, 4-methyl-1,4-pentanediol dimethacrylate, divinylbenzene and/or trivinylbenzene, and component B being an aqueous solution of a styrene copolymer with acrylic acid, maleimide and/or maleic anhydride. 
     
     
         2 . The method as claimed in  claim 1 , wherein component A possesses a glass transition temperature >90° C. 
     
     
         3 . The method as claimed in  claim 1 , wherein component B possesses a molecular weight in the range from 3000 to 15 000 g/mol, optionally 3000 to 7000 g/mol. 
     
     
         4 . The method as claimed in  claim 1 , wherein the aqueous polymer dispersion is applied in combination with one or more calcium and/or magnesium salts, often naturally occurring in processing water, and/or component C, a cationic fixative, any of which promote coagulation of aqueous emulsion particles. 
     
     
         5 . The method as claimed in  claim 4 , wherein the aqueous polymer dispersion is pre-mixed with one or more calcium and/or magnesium salts or Component C, before adding the components to the fibrous slurry, during pulp and/or paper manufacture. 
     
     
         6 . The method as claimed in  claim 4 , wherein component C is selected from the group consisting of: polyethyleneimine (PEI), polydiallyldimethylammonium chloride (polyDADMAC), polyvinylamine (PVAm), polyaluminum chloride (PAC), zirconium salts, polyacrylamide (PAAM), polyamine and polyamideamine. 
     
     
         7 . The method as claimed in  claim 1 , wherein the aqueous polymer dispersion further comprises a component D in the form of a surfactant. 
     
     
         8 . The method as claimed in  claim 1 , wherein a water fraction of the aqueous polymer dispersion is 93% to 17.7%, preferably optionally 80% to 45% by weight. 
     
     
         9 . An aqueous polymer dispersion for coagulating and detackifying pitch in the processing of wood pulp and/or during the papermaking procedure, comprising a component A selected from a homopolymer and/or copolymer of the following group: acrylic acid and/or one or more alkyl esters thereof, or methacrylic acid and/or one or more alkyl esters thereof, styrene and/or methylstyrene, vinyl acetate, itaconic acid, glycidyl methacrylate, 2-hydroxyalkyl (meth)acrylate, methacrylamide, N-hydroxyethyl(meth)acrylamide, dimethacrylate monomers, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, 4-methyl-1,4-pentanediol dimethacrylate, divinylbenzene and/or trivinylbenzene, and component B, which is an aqueous solution of a styrene copolymer with acrylic acid, maleimide and/or maleic anhydride. 
     
     
         10 . The aqueous polymer dispersion as claimed in  claim 9 , wherein the dispersion is present in combination with one or more calcium and/or magnesium salts, often naturally occurring in processing water, and/or component C, a cationic fixative, selected from the group consisting of: polyethyleneimine (PEI), polydiallyldimethylammonium chloride (polyDADMAC), polyvinylamine (PVAm), polyaluminum chloride (PAC), zirconium salts, polyacrylamide (PAAM), polyamine and polyamideamine. 
     
     
         11 . The aqueous polymer dispersion as claimed in  claim 9 , wherein the dispersion comprises a further component D in the form of a surfactant. 
     
     
         12 . The aqueous polymer dispersion as claimed in  claim 9 , which comprises
 2% to 50%, optionally 5% to 30% of component A,   1% to 30%, optionally 3% to 10% of component B,   100 to 400 ppm calcium and/or magnesium carbonate (water hardness)   0% to 2% of component C,   0% to 0.3%, optionally 0% to 0.2% of component D, and   96% to 17.7%, optionally 90% to 45% of water (component E).   
     
     
         13 . An aqueous polymer dispersion comprising a component A and a component B, component A being a homopolymer and/or copolymer of methyl methacrylate, acrylate and/or styrene and component B being an aqueous solution of styrene copolymer with acrylic acid, maleimide and/or maleic anhydride, capable of being used for coagulating and detackifying pitch particles in processing of pulp and/or paper. 
     
     
         14 . A dispersion as claimed in  claim 13 , wherein the polymer dispersion is further combined with one or more calcium and/or magnesium salts and/or natural water hardness in pulp and/or papermaking process water and/or component C, a cationic fixative, optionally when waterhardness is below 15-20° dH. 
     
     
         15 . A disperions as claimed in  claim 13 , whereby the amount of aqueous dispersion has been applied to a cellulosic pulp slurry is in an amount of optionally 0.05 to 0.5%, or optionally 0.1 to 0.2%, based on dry weight of cellulose.