METHOD FOR IMPROVING OPTICAL PROPERTIES OF PAPER Russian patent published in 2013 - IPC D21H21/30 

FIELD: textiles, paper.

SUBSTANCE: in one of the aspects, the invention is directed to a method which enables mainly to maintain (or even increase) the brightness and/or whiteness of paper with increased degree of grinding the cellulose pulp, where the said method comprises grinding of the cellulose pulp till the freeness value of about 100 CSF and adding the composition OVA and a polymeric carrier to the paper surface in the size press in amounts sufficient to increase brightness and/or whiteness of the paper obtained. In another aspect, the invention is directed to a method of making paper from grinded cellulose pulp, which comprises grinding the suspension of cellulosic fiber to reduce the freeness up to about 100 CSF and mixing the cellulosic fiber with at least one optical bleaching agent (OBA) during or after the grinding stage and prior to adding any additional chemical ingredients of the wet stage of production.

EFFECT: effective maintenance or increase of brightness and whiteness of paper from the grinded cellulose pulp.

13 cl, 14 tbl, 34 dwg