METHOD FOR PRODUCING DEINKED PULP AND DEINKED PULP

摘要

PROBLEM TO BE SOLVED: To provide a method for producing deinked pulp that contains a small amount of unreleased ink remaining therein, and to provide deinked pulp.SOLUTION: The method for producing deinked pulp comprises: a disintegration step of disintegrating printed waste paper; a dust removal step of removing foreign matters; a dispersion step of finely dispersing the foreign matters; and a deinking step of removing ink. In one or more steps of either the disintegration step or the dispersion step, one or more ampholytic surface active agents (A) represented by either a general formula (A-1) or a general formula (A-2) are used. The deinked pulp produced by the producing method is also disclosed. In the general formula, Ris an alkyl group or an alkenyl group having 8-24 carbon atoms, Ris an alkyl group or an alkenyl group having 7-23 carbon atoms, and R, R, Rand Rare each independently an alkyl group or a hydroxy group having 1-4 carbon atoms.