Retention system

Abstract

There is provided a method for flocculating one or more particulate materials present in a dispersion, the method comprising contacting the dispersion with (i) fibrous cationic colloidal alumina microparticles; and (ii) a cationic polymer and/or a non-ionic polymer.

1 . A method for flocculating one or more particulate materials present in a dispersion, the method comprising contacting the dispersion with 
 (i) fibrous cationic colloidal alumina microparticles; and    (ii) a cationic polymer and/or a non-ionic polymer.    
     
     
         2 . A method according to  claim 1  wherein the dispersion is aqueous based.  
     
     
         3 . A method according to  claim 1  or  2  wherein the dispersion comprises or is components of papermaking stock.  
     
     
         4 . A method according to  claim 3  wherein the papermaking stock is a pulp of a hardwood or of a softwood, or a combination thereof.  
     
     
         5 . A method according to  claim 4  wherein the pulp is selected from pulps of the chemical, mechanical, recycled, semi-chemical and thermomechanical types, or mixtures thereof.  
     
     
         6 . A method according to any one of the preceding claims wherein the one or more particulate materials are flocculated on a fibrous material.  
     
     
         7 . A method according to  claim 6  wherein the fibrous material comprises or is fibrous cellulose.  
     
     
         8 . A method according to any one of the preceding claims wherein the dispersion is contacted with a composition comprising 
 (i) fibrous cationic colloidal alumina microparticles; and    (ii) a cationic polymer and/or a non-ionic polymer.    
     
     
         9 . A method according to any one of the preceding claims wherein the cationic polymer is selected from polyacrylamide, polyethylene imine, polyamines, polycyandiamide formaldehyde polymers, amphoteric polymers, diallyl dimethyl ammonium chloride polymers, diallylaminoalkyl (meth)acrylate polymers, and dialkylaminoalkyl (meth)acrylamide polymers, a copolymer of acrylamide and diallyl dimethyl ammonium chloride, a copolymer of acrylamide and diallyaminoalkyl (meth)acrylates, a copolymer of acrylamide and dialkylaminoalkyl (meth)acrylamides, a polymer of dimethylamine and epichlorohydrin, and natural and semi-synthetic polymers including cationic starch.  
     
     
         10 . A method according to any one of the preceding claims wherein the non-ionic polymer is selected from polymers formed from at least one monomer chosen from acrylamide, methacrylamide, and N-tertiary butyl acrylamide.  
     
     
         11 . A method according to any one of the preceding claims wherein the charge density of the cationic polymer is no greater than 60%.  
     
     
         12 . A method according to any one of the preceding claims wherein the molecular weight of the cationic/non-ionic polymer is no greater than 30,000,000, preferably 500,000 to 30,000,000, more preferably 1,000,000 to 30,000,000, more preferably 5,000,000 to 30,000,000.  
     
     
         13 . A method according to any one of the preceding claims wherein the polymer:microparticle ratio is from 10:1 to 1:10, preferably 2:1 to 1:2, more preferably approximately 1:1.  
     
     
         14 . A method according to any one the preceding claims wherein the dispersion is contacted with the cationic alumina prior to contact with the cationic polymer and/or the non-ionic polymer.  
     
     
         15 . A method according to any one of  claims 1  to  13  wherein the dispersion is contacted with the cationic polymer and/or non-ionic polymer prior to contact with the cationic alumina.  
     
     
         16 . A method according to any one of  claims 1  to  13  wherein the dispersion is simultaneously contacted with the cationic polymer and/or non-ionic polymer and the cationic alumina.  
     
     
         17 . A method according to any one of the preceding claims wherein the dispersion has a pH of from 3to 10.  
     
     
         18 . A method for retention and/or drainage of a papermaking stock as defined in any one of the preceding claims.  
     
     
         19 . A method according to  claim 18  wherein the papermaking stock has a concentration of pulp of up to 20 wt. %.  
     
     
         20 . A method according to  claim 19  wherein the papermaking stock has a concentration of pulp of 1-2 wt. %.  
     
     
         21 . A method according to  claim 19  wherein the papermaking stock has a concentration of pulp of 3-5 wt. %.  
     
     
         22 . Use of fibrous cationic colloidal alumina microparticles for flocculating one or more particulate materials present in a dispersion characterised by the features of any one of  claims 1  to  17 .  
     
     
         23 . A composition comprising 
 (i) fibrous cationic colloidal alumina microparticles; and    (ii) a cationic polymer and/or a non-ionic polymer.    
     
     
         24 . Paper or a paper product obtained or obtainable using the invention as defined in any one the preceding claims.  
     
     
         25 . A flocculated particulate material obtainable by the method according to  claim 1  or any claim dependent thereon.  
     
     
         26 . A method as substantially hereinbefore described with reference to any one of the Examples.  
     
     
         27 . A use as substantially hereinbefore described with reference to any one of the Examples.  
     
     
         28 . A composition as substantially hereinbefore described with reference to any one of the Examples.  
     
     
         29 . A paper or a paper product as substantially hereinbefore described with reference to any one of the Examples.  
     
     
         30 . A flocculated particulate material as substantially hereinbefore described with reference to any one of the Examples.