Patent ID: 6248209
Filing Date: 2001-06-19
Classification: D21C

Abstract:
A method of bleaching cellulose pulp, comprising bleaching an alkaline aqueous slurry of cellulose pulp with a bleaching agent in the presence of a bleaching assistant compound, wherein the cellulose pulp is bleached with an amount of a chlorine-containing bleaching agent before or after the cellulose pulp is bleached with the bleaching agent, the bleaching assistant compound being represented by formula (1):R.sup.1 --O--{(C.sub.2 H.sub.4 O).sub.m /(AO).sub.n }--H (1)wherein R.sup.1 is a branched alkyl group having 6 to 12 carbon atoms, m is an average added mol number of 4 to 15, A is a propylene, butylene or phenylethylene group, n is an average added mol number of 0 to 4, and the (C.sub.2 H.sub.4 O).sub.m /(AO).sub.n is in a random or block form, wherein the bleaching assistant compound is present in an amount such that the amount of the chlorine-containing bleaching agent used to bleach the cellulose pulp is reduced as compared to bleaching assistant compounds which do not contain the branched alkyl group having 6 to 12 carbon atoms.