To enable waste paper materials to be deinked so as to have high brightness through the flotation using a nonionic surfactant obtained by the addition polymerization of ethylene oxide, an alkylene oxide and ethylene oxide in this order with an alcohol, and fats and oils (or a fatty acid).
This deinking agent is prepared comprising at least one kind selected from nonionic surfactants obtained by the addition polymerization of ethylene oxide(EO), an alkylene oxide(AO) and ethylene oxide(EO) in this order with a mixture of a compound of the formula, RO-(EO)x(AO)y(EO)zH [wherein, AO is an alkylene oxide comprising at least propylene oxide or butylene oxide; (x), (y) and (z) are each 0.5-100; and R is a 8-36C alkyl or alkenyl or the like] or the formula, R'COO-(EO)x(AO)y(EO)zH [wherein, R' is a 7-35C alkyl or alkenyl], oil and fat, and a monohydric or polyhydric alcohol.
MIYAUCHI YOSHITAKA
HAMAGUCHI KOJI
EDO TAKESHI
HAMADA YOSHITO
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