| 摘要 |
PURPOSE:To give a specific mechanical strength or more until it is supplied to a mold and collapse it quickly into crystalline particles at compression molding by using petroleum resin, which has a specified molecule weight as a binder for granular magnetic powder. CONSTITUTION:This contains 5wt.% or more aliphatic or aromatic petroleum resin, where the average molecule weight is 3000 or less, as a binder of granular magnetic powder. The compression molding of the granular material powder is performed after injecting good solvent of petroleum into a mold supplied with material powder. The petroleum resin in the thermoplastic resinous substance, which is gotten by cation-polymerizing a higher unsaturated hydrocarbon contained in naphta or the like. Moreover, as the binder other than the petroleum resin, paraffin, higher fatty acid, higher alcohol, or the like is used. As a usable good solvent, there are tetrahydroflane, dimethylformamide, toluene, trichloroethane, etc. |
