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AssigneeKemira Oyj
InventorsJonni Ahlgren, Aarto Paren, Jukka Jakara, Timo Harma, Ilkka Renvall
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The present invention relates to a polymer composition for peroxide bleaching of a cellulosic fibre material, said composition being in the form of a stable aqueous polymer solution obtained by bringing 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, into contact with a second polymer (B) comprising a po9lylactone of a poly-alfa-hydroxyacrylic acid in solid form or as a moist powder or as a slurry, said polymer solution having a pH of at most 8, The invention also relates to peroxide bleaching processes.
A polymer composition for peroxide bleaching of a cellulosic fibre material, said composition being in the form of a stable aqueous polymer solution obtained by bringing 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, into contact with a second polymer (B) comprising a polylactone of a poly-alfa-hydroxyacrylic acid in solid form or as a moist powder or as a slurry, said polymer solution having a pH of at most 5.
A process for bleaching a cellulosic fibre material with a peroxide compound in an aqueous alkaline medium, comprising a step of adding to the cellulosic fibre material a polymer composition in the form of a stable polymer solution obtained by bringing 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, into contact with a second polymer (B) comprising a polylactone of a poly-alfa-hydroxyacrylic acid in solid form or as a moist powder or as a slurry, said polymer solution having a pH of at most 5.
A process for bleaching a cellulosic fibre material with a peroxide compound in an aqueous alkaline medium, comprising treating the cellulosic fibre material with an alkaline substance, a peroxide compound and a stabilizing composition, said composition being in the form of a stable polymer solution obtained by bringing 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, into contact with a second polymer (B) comprising a polylactone of a poly-alfa-hydroxyacrylic acid in solid form or as a moist powder or as a slurry, said polymer solution having a pH of at most 5.
Dependencies are inferred from the claim text.