Method for producing high whiteness deinked pulp

摘要

PPROBLEM TO BE SOLVED: To provide a method for producing high-whiteness deinked waste paper pulp, at lower power basic unit than ever without impairing the efficiency of separating ink from waste paper. PSOLUTION: The method for producing the high-whiteness deinked pulp from printed waste paper comprises the following process. In the waste paper-disaggregating step, a pulper is charged with a polyethylene glycol-type nonionic surfactant of the general formula (I) (wherein, R is a 12-18C alkyl; AO is a 2-4C oxyalkylene group; and n is an integer of 5 or greater) with a clouding point of 0-25C; there is then provided a wire washing step comprising washing off ink from the printed waste paper on 40 to 100-mesh wires, and the resultant waste paper is then subjected to a bleaching or kneading step using at least one deinking agent selected from fatty acid- or fatty acid derivative-based deinking agents. PCOPYRIGHT: (C)2007,JPO&INPIT