High density record including carbon black particles purified by electrolysis
AssigneeVictor Company of Japan, Ltd.
InventorsToshikazu Goshima, Akira Nishizawa, Kazuhira Namikawa, Toshiaki Hamaguchi, Mutsuaki Nakamura
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Abstract
A high density information record of the electrostatic capacitance type which comprises a record substrate on which signal information is recorded as geometric variations. The substrate is made of a vinyl chloride resin, and carbon black which is purified by electrolysis to remove impurities therefrom.
Claims3
A method for producing a high density information record of the electrostatic capacitance type which comprises a record substrate on which signal information is recorded as geometric variations, the substrate being made of a mixture of a vinyl chloride resin and carbon black used in an amount of from 5 to 30% by weight of the vinyl chloride resin, said method comprising the steps of purifying carbon black by electrolysis to remove sulfur, calcium, silica and aluminum impurities therefrom and mixing a vinyl chloride resin with from 5 to 30% by weight, based on the vinyl chloride resin, of said purified carbon black.
Dependencies are inferred from the claim text.