Manufacture of paper and paperboard

摘要

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, characterized in that the suspension is flocculated using a flocculation system comprising a clay 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 polymer has(a) intrinsic viscosity above 1.5 dl/g and/or saline Brookfield viscosity of above about 2.0 mPa.s and(b) rheological oscillation value of tan delta at 0.005 Hz of above 0.7 and/or(c) deionised SLV viscosity number which is at least three times the salted SLV viscosity number of the corresponding unbranched polymer made in the absence of branching agent.