Styrene copolymers in de-inking

摘要

Provided herein are compositions of matter useful in de-inking secondary fibers. A composition according to the invention includes an aqueous solution of an anionic form of a styrene-methacrylic acid copolymer. When a surfactant is used in combination with the copolymers herein described in a de-inking operation, a synergy is observed in that the combination of copolymer and surfactant combination together yield a recycled fiber product having higher brightness level and a lower effective residual ink concentration than recycled fibers produced using either the copolymer or surfactant alone in the same operation.