Patent ID: 7731818

Claim:
A process for deinking waste paper comprising treating the waste paper with a peroxide compound in an aqueous alkaline medium in the presence of polymers, said process comprising introducing the polymers in the form of a polymer solution having a pH of at most 7 and comprising a first polymer (A) comprising a Ca-binding polymer in the form of a polycarboxylate polymer which is a copolymer of acrylic acid and/or methacrylic acid with maleic acid or itaconic acid, and a second polymer (B) comprising a poly-alpha-hydroxyacrylic acid or a salt thereof or the corresponding polylactone, said process additionally comprising treating the waste paper with at least one non-ionic surfactant or with at least one combination of a non-ionic surfactant and a fatty acid or a salt thereof to promote ink detachment and/or ink removal.