Controllable filler prefloculation using a dual polymer system

摘要

A method of preparing a stable dispersion of flocculated filler particles for use in papermaking processes comprises sequential addition of a first flocculating agent to an aqueous dispersion of filler particles followed by shearing of the dispersion, followed by addition of a second flocculating agent to the dispersion and further shearing of the resultant filler flocs to the desired particle size resulting in shear resistant filler flocs with a defined and controllable size distribution. In addition, a neutralizing coagulant can be added to the dispersion to partially or completely neutralize the charge of the filler before the first flocculating agent is added.

主权项

1. A method of preparing a stable dispersion of flocculated filler particles having a specific particle size distribution for use in papermaking processes comprising
a) providing an aqueous dispersion of filler particles; b) adding a first flocculating agent to the dispersion in an amount sufficient to mix uniformly in the dispersion without causing significant flocculation of the filler particles, and the first flocculating agent being amphoteric; c) adding a second flocculating agent to the dispersion in an amount sufficient to initiate flocculation of the filler particles in the presence of the first flocculating agent wherein the second flocculating agent has opposite charge to the net charge of the first amphoteric flocculating agent; d) shearing the flocculated dispersion to provide a dispersion of filler flocs having the desired particle size; e) flocculating the filler particles prior to adding them to a paper stock and wherein no paper stock is present during the flocculation; and t) adding the filler particles to a paper stock.