Patent ID: 6395134
Filing Date: 2002-05-28
Classification: D21H

Abstract:
A process of making paper or paper board comprising forming a cellulosic suspension, flocculating the suspension, draining the suspension on a screen to form a sheet and then drying the sheet,characterised in that the suspension is flocculated using a flocculation system comprising a water soluble cationic polymer, a siliceous material and an anionic branched water soluble polymer that has been formed from water soluble ethylenically unsaturated anionic monomer or monomer blend and branching agent and wherein the anionic polymer has(a) intrinsic viscosity of at least 4 dl/g and (b) rheological oscillation value of tan delta at 0.005 Hz of above 0.7 calculated on a 1.5% by weight aqueous solution of polymer and/or (c) deionised SLV viscosity number which is at least three times the salted SLV viscosity number of the corresponding unbranched anionic polymer made in the absence of branching agent, wherein the water-soluble cationic polymer is added to the cellulosic suspension and then the suspension is mechanically sheared after which the siliceous material and anionic branched water soluble polymer are added.