Patent ID: 7750054

Claim:
A method of preparing a sizing emulsion, comprising the steps of: (a) combining an alkenyl succinic anhydride sizing agent and a cationic synthetic polymer emulsifier to form a mixture; (b) applying a shear force to said mixture using a plurality of rotating blades driven by a variable speed drive to form an emulsion including particles of the alkenyl succinic anhydride distributed within the emulsifier, said shear force sufficient to provide an energy factor index in a range of 620 to 1020 per one minute of contact time; (c) dividing said emulsion into first and second parts; (d) recycling said first part of said emulsion to rejoin said mixture of step (a); (e) directing said second part of said emulsion to an output, wherein the combination of said applying a shear force to said mixture using the plurality of rotating blades and said recycling said first part of said emulsion results in a mean diameter of the particles of alkenyl succinic anhydride in said second part of said emulsion being in a range of about 0.1 to about 3.0 microns; and (f) continuously monitoring the mean diameter of the particles at the output and adjusting the speed of said rotating blades to maintain the mean diameter of the particles of the alkenyl succinic anhydride in the second part of said emulsion in the range of about 0.1 to about 3.0 microns.