Patent ID: 7867357
Filing Date: 2011-01-11
Classification: C01B,C08L,C11D,D06L,D21C

Abstract:
1. A process for bleaching a cellulosic fiber material with a peroxide compound in an aqueous alkaline medium, comprising a step of adding to the cellulosic fiber material a polymer composition in the form of a stable polymer solution obtained by contacting in an aqueous medium a first polymer (A) comprising a partly or totally acidic homopolymer of acrylic acid, methacrylic acid or maleic acid, or a copolymer of acrylic acid and/or methacrylic acid with an unsaturated dicarboxylic acid, with a second polymer (B) comprising a polylactone of a poly-alpha-hydroxyacrylic acid in solid form or as a moist powder or as a slurry, said polymer solution having a pH of at most 5.