Rca Inc.

Max Derendinger

Helmut G Kiess

Bruno K Binggeli

Capacitive electronic discs having thin conductive layers are prepared by coating a core disc with a finely particulate conductive composition comprising a thermoplastic resin, conductive carbon black particles and suitable additives. The powder coating is compressed under heat and pressure to fuse the powder to the surface of the core disc. An information pattern is embossed therein, preferably simultaneously.

Method of producing capacitive electronic discs

Thin, flexible capacitive electronic discs are formed by directly compression molding a powder composition having a particle size such that no particles are larger than about 400 micrometers and a substantial portion is between about 25 and 300 micrometers and comprising a thermoplastic resin, conductive carbon black particles and suitable additives. An information track is embossed into at least one surface of the disc, preferably simultaneously with the molding step. The discs are from about 0.15 to 0.6 mm thick. Preferably, the discs are about 0.2 mm thick, which is about one-tenth of the thickness of present commercial discs.

An apparatus is shown for applying a homogeneous uniform layer of a powder to a surface of a part. The apparatus utilizes two belts which are made to track about two pairs of rollers in unison. A hopper containing the powder having an opening in the bottom is disposed so that the opening is closed off by one or both of the belts except for a slit aperture. The aperture is formed by a space between abutting ends of the two belt-roller assemblies. The apparatus is arranged so that as the belts track about the rollers the aperture traverses the opening in the hopper thereby permitting powder to pass through the aperture and fall to the part to be coated which is positioned directly below the opening.

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Zurich, Switzerland

Max Derendinger