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:
Jun. 11, 2002
Filed:
Aug. 25, 1999
Bridgestone Corporation, Tokyo, JP;
Abstract
There are disclosed a composition for resin magnets which comprises a thermoplastic resin and magnetic powders and which, when determined in a heated molten state, has specific viscosity characteristics characterized in that the almost linear line which is obtained by taking &eegr; /&eegr; as ordinate and &ggr; as abscissa has a slope of at most 0.02, preferably at most 0.01 within a specific temperature range in which &eegr; falls within the range of from 2.0×10 to 1.0×10 dyne/cm , wherein &eegr; denotes shear stress (dyne/cm ), &eegr; denotes yield stress (dyne/cm ) and &ggr; denotes shear rate (S ); a magnetic member which is produced by the use of the above composition for resin magnets; and a process for efficiently producing the magnetic member from the composition by an extrusion molding in a magnetic field under specific temperature and pressure conditions. The above composition for resin magnets has specific viscosity characteristics, and thereby enables to readily afford a magnetic member having a strong magnetic force such as magnet rollers and magnet pieces. Accordingly, the magnetic member is well suited for use in the field of electrophographic equipment and electrostatic recording equipment such as copying machinery, facsimile machinery and printers.