Patent Number: 6,251,220

Title: Wastepaper deinking method using amine or acid salt of amine in the flotation stage

Abstract: A deinking method comprising the steps of liberating ink from waste paper as a raw material and removing the liberated ink from a flotation system, wherein a nonionic surfactant, e.g., a reaction product obtained by adding an alkylene oxide to a mixture of an oil & fat and an alcohol, an alkylene oxide adduct of a fatty acid, or an alkylene oxide adduct of a higher alcohol, is used for the liberation of ink, and the flotation step is effected in the presence of a cationic compound, an amine, an acid salt of an amine or an amphoteric compound at a pH of from 4 to 9, provides a high quality deinked pulp having a high whiteness and a little residual ink spots.

Inventors: Irinatsu; Yuichi (Wakayama, JP), Miyauchi; Yoshitaka (Wakayama, JP), Takahashi; Hiromichi (Wakayama, JP)

Assignee: Kao Corporation

International Classification: D21C 5/02 (20060101); D21C 005/02 ()

Expiration Date: 06/26/2018