Patent ID: 8747617

Claim:
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.