Patent ID: 6712933
Filing Date: 2004-03-30
Classification: D21H

Abstract:
A method of making paper or paperboard comprising:a) introducing at least one acidic aqueous alumina sol and at least one synthetic hectorite microparticle additive to a papermaking pulp to form a treated pulp; and b) forming the treated pulp into paper or paperboard; wherein said acidic aqueous alumina sol contains elongated secondary particles that are elongated from about 50 nm to about 300 nm in only one plane and are formed by edge-to-edge coagulation of rectangular plate-like primary particles having a length on one side of from about 10 nm to about 30 nm when observed through an electron microscope, and wherein said acidic aqueous alumina sol is made of particles having an alumina hydrate boehmite structure and said acidic aqueous alumina sol is added in amounts of from about 0.01% to about 0.5% by weight based on dried solids weight of both said sol and said pulp.