FILLER FOR PAPERMAKING PROCESS

摘要

The present invention relates to a filler comprising calcium salt and cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the filler is substantially free from fibres or fibrils of cellulose or lignocellulose. The invention also relates to a filler comprisi ng calcium salt and a cellulose derivative having a degree of substitution of n et ionic groups up to about 0.65, wherein the cellulose derivative contains cationic groups. The invention further relates to a method of producing a filler which comprises mixing a calcium salt-containing material with a cellulose derivative having a degree of substitution of net ionic groups up to about 0.65 in the substantial absence of fibres or fibrils of cellulose or lignocellulose. The invention also relates to a method of producing a filler which comprises mixing a calcium salt-containing material with a cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the cellulose derivative contains cationic groups. The inventi on further relates to a filler obtainable by the methods. The invention further relates to a papermaking process which comprises providing an aqueous suspension containing cellulosic fibres, introducing into the suspension a filler comprising calcium salt and cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the filler is substantially free from fibres or fibrils of cellulose or lignocellulose, an d dewatering the suspension to form a web or sheet of paper. The invention als o relates to a papermaking process which comprises providing an aqueous suspension containing cellulosic fibres, introducing into the suspension a filler calcium salt and cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the cellulose derivative contains cationic groups, and dewatering the suspension to form a web or she et of paper.