AQUEOUS MAGNETIC DISPERSION, ITS PREPARATION, ITEM PRINTED IN AQUEOUS MAGNETIC DISPERSION INK, ITS PRINTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an aqueous magnetic dispersion suitable for ink jet recording, especially an aqueous magnetic dispersion which is used for an aqueous magnetic ink which is excellent in dispersibility of magnetic superfine particles, dispersion stability and stock stability of the ink and can realize a magnetic printed item which can optionally be used for normal magnetic recording because of its high residual magnetic flux density. ;SOLUTION: This aqueous magnetic dispersion contains a copolymer, an amphipathic compound and magnetic superfine particles. The magnetic superfine particles are synthesized through an aqueous reaction process which does not include a drying process, are in a form of an aqueous dispersion and are in a crystalline form. The copolymer contains styrene and acrylic acid. The amphipathic compound contains polyethylene oxide and aromatic rings. The average particle size of the magnetic superfine particles is preferably not more than 50 nm.;COPYRIGHT: (C)2000,JPO