The Relationship Between the State of Kneading and the Dispersion of a Magnetic Powder and Toughness of Magnetic Paint Film

Abstract

Magnetic powder and a binder were continuously kneaded by the twinscrew extruder under various condition. The kneaded mixture was diluted and dispersed to make magnetic paint. The kneading and dispersion state was evaluated as a coated magneic film by gloss, magnetic characteristic, surface roughness, and electromagnetic characteristics. The toughness of the magnetic film was evaluated by density, and dynamic modulas.
As a result, the magnetic powder was well-dispersed by high shear kneading at the high motor output of the extruder, and the surface roughness, magnetic and electromagnetic characteristics were improved. The magnetic powder was densely packed improving the density of the magnetic film. Especially, the dynamic modulas was greatly improved at a high temperature. This indicates that there is an improvement in the durability of magnetic tape at the high temperature.