MAGNETIC RUBBER COMPOSITION, MAGNETIC RUBBER MOLDED ARTICLE, MAGNETIC ENCODER, AND PRODUCTION METHOD THEREFOR

摘要

Provided is a magnetic rubber composition containing hydrogenated nitrile rubber (A), ferrite magnetic powder (B), a vulcanizing agent (C), and stearic acid (D), wherein the hydrogenated nitrile rubber (A) has a Mooney viscosity (ML₁₊₄, 100°C) of 45-80, the magnetic rubber composition contains 1250-1600 parts by mass of the ferrite magnetic powder (B), 0.1-4 parts by mass of the vulcanizing agent (C), and 2.5-8 parts by mass of the stearic acid (D) to 100 parts by mass of the hydrogenated nitrile rubber (A), and the content of the ferrite magnetic powder (B) relative to the mass of the entire magnetic rubber composition is 91-93 mass%. Since the magnetic rubber composition has excellent fluidity while containing magnetic powder of an extremely high density, by vulcanizing the foregoing, it is possible to obtain a magnetic rubber molded article provided with both excellent magnetic properties and good mechanical properties.