Materials for use in making paper

摘要

A branched and wholly water soluble anionic polymer which has been made by conventional reverse phase emulsion polymerisation of a water soluble ethylenically unsaturated anionic monomer charge and 0.5 to 10 ppm branching agent to form an emulsion, and then substantially dehydrating the emulsion to form a stable dispersion of substantially anhydrous polymer droplets dispersed in oil, and wherein the polymer has (c) intrinsic viscosity above 3dl/g and (d) tan delta rheological oscillation value at 0.005Hz of above 0.5 or deionised SLV viscosity number which is at least three times the salted SLV viscosity number of the corresponding polymer made in the absence of branching agent. The polymer can be used in paper making and gives an improved combination of formation, retention and drainage.