Filler for papermaking process

摘要

The present invention relates to a filler comprising calcium salt and anionic cellulose derivative having a degree of substitution of net anionic groups up to 0.60, wherein the filler is free from fibres or fibrils of cellulose or lignocellulose. The invention also relates to paper comprising the filler according to the invention. The invention further relates to a method of producing a filler which comprises mixing a calcium salt-containing material with an anionic cellulose derivative having a degree of substitution of net anionic groups up to 0.60 in the absence of fibres or fibrils of cellulose or lignocellulose. The invention further relates to a papermaking process which comprises providing an aqueous suspension containing cellulosic fibres, introducing into the suspension the filler according to the invention, and dewatering the suspension to form a web or sheet of paper.