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:
Aug. 11, 2009
Filed:
Apr. 19, 2007
Naoki Uchida, Ohtake, JP;
Ryo Iwai, Ohtake, JP;
Mamoru Kamigaki, Ohtake, JP;
Shinji Uemoto, Ohtake, JP;
Koso Aoki, Ohtake, JP;
Hiromitsu Misawa, Ohtake, JP;
Naoki Uchida, Ohtake, JP;
Ryo Iwai, Ohtake, JP;
Mamoru Kamigaki, Ohtake, JP;
Shinji Uemoto, Ohtake, JP;
Koso Aoki, Ohtake, JP;
Hiromitsu Misawa, Ohtake, JP;
Toda Kogyo Corporation, Hiroshima-shi, Hiroshima-ken, JP;
Abstract
The present invention relates to black magnetic iron oxide particles comprising core particles and a surface layer formed on a surface of the respective core particles which is made of a compound of at least one alkali earth metal element selected from the group consisting of Mg, Ca, Sr and Ba and an aluminum element, in which a content of the at least one alkali earth metal element present in the surface layer is from 100 ppm to 1000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a content of the aluminum element present in the surface layer is from 1000 ppm to 20000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a ratio [A/B] of the content [A (ppm)] of the aluminum element to the content [B (ppm)] of the at least one alkali earth metal element present in the surface layer is from 1 to 100; and a molded product comprising said black magnetic iron oxide particles has a breakdown voltage of not less than 400 V/cm.