| abstract |
PURPOSE:To obtain the plastic magnet composition showing a highly efficient magnet characteristics at relatively low cost by a method wherein Nd-Fe-B family is used as a magnetic material, and its powder is coated with dyestuffs. CONSTITUTION:The magnetic powder indicated by the composition formula RxMyBz (the R in the formula indicates rare-earth element, M indicates iron group element, and x, y and z indicate atom% on condition of 8<=x<=30, 2<=z <=20 and y=100-x-z) has excellent magnet characteristics, but as it is inflammable when it comes in contact with air when it is heated up while it is mixed and fused with plastic, the magnetic material is coated by dyestuffs in advance. As the dyestuffs, direct dyes, acid dyes, basic dyes, mordant dyes, sulphite dyes, vat dyes, disperse dyes, oil-soluble dyes, reactive dyes and a fluorescent brightening agent can be included. Pertaining to the quantity of the dyes to be coated, 0.02-2wt% is considered desirable for the magnetic powder. |