The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 2026
Filed:
Aug. 24, 2021
Dowa Electronics Materials Co., Ltd., Tokyo, JP;
Yasuto Miyamoto, Tokyo, JP;
DOWA ELECTRONICS MATERIALS CO., LTD., Tokyo, JP;
Abstract
A dispersed iron oxide magnetic powder slurry, in which the average secondary particle diameter of ε-type iron oxide measured with a dynamic light scattering particle size distribution analyzer is 65 nm or less, and which has good dispersibility, is obtained by adding a quaternary ammonium salt serving as a first dispersant and an alkali to a slurry containing ε-type iron oxide particles to bring the pH at 25° C. to 11 or higher, and thereafter adding an organic compound, which is an organic acid serving as a second dispersant and having two or more carboxy groups in the molecule, and in which one type or two types of a hydroxy group and an amino group are bound to carbon that does not constitute a carboxy group other than the carboxy groups to bring the pH at 25° C. of the slurry to 4 or higher and lower than 11.