Patent ID: 6524439
Filing Date: 2003-02-25
Classification: D21H

Abstract:
A process for 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,wherein the suspension is flocculated by adding a flocculation system comprising a siliceous material and organic polymeric microparticles which have an unswollen particle diameter of less than 750 nanometers, in which the total charge in the organic polymeric microparticle is greater that about 1%, and in which the siliceous material is selected from the group consisting of silica sols, colloidal silica, colloidal silicic acid, polysilicic microgels, aluminated polysilicic acid, polyaluminosilicates consisting of silicic microparticles, silica microgels, polyparticulate polysilicic microgels, colloidal borosilicate, polyborosilicates, cationic silica and swellable clay, wherein the flocculating system comprises, i) adding up to 400 ppm by weight organic polymeric microparticle and at least 500 ppm by weight of siliceous material, or ii) the organic polymeric microparticle and siliceous material is added as a premixed composition.