Deinking agent and deinking method by flotation using the deinking agent

摘要

PURPOSE:To obtain a deinking agent capable of providing high-quality reclaimed pulp having high whiteness and hardly any residual ink and achieving stable operating efficiency. CONSTITUTION:This deinking agent comprises (a) compounds expressed by formulas I and II. R1O-(PO)m1-(EO)n1-(XO)k1-R2 (I) and R3O-(PO)m2-[(EO)n2.(PO) m3)]R4 (II) (R1 and R3 are 12-22C alkyl or alkenyl group; R2 and R4 are hydrogen or 2-24C acyl group; PO, EO and XO each are propylene oxide, ethylene oxide and =3C alkylene oxide units; m1 is 1-8; n1 is 10-40; k1 is a number providing 3-120sum total of carbon atoms in polymerized XO; m2 is 1-8; n2/m3 is 0.4-2.0; n2 is 10-40; m3 is 7-45; the addition form of PO and EO is block and the addition form in [] in formula II is random).