Victor Company of Japan, Limited

Tokuyama Sekisui Industry Corporation, Limited

Shin-etsu Chemical Co., Ltd.

Toshiaki Hamaguchi

Kazuhira Namikawa

Mutsuaki Nakamura

Akio Kuroda

Akio Hata

Noriki Fujii

Toshikazu Goshima

Toshio Akai

Akira Nishizawa

Yoshiaki Kudo

An information signal record medium of an electrostatic capacitance type in which a signal information is recorded as geometric variations is described. The medium is made of a conductive resin composition which comprises a vinyl chloride resin and 5 to 30 parts by weight of conductive particles based on 100 parts by weight of the vinyl chloride resin. The vinyl chloride resin is obtained by polymerizing at least one monomer for the vinyl chloride resin in which from 0.2 to 1 parts by weight of a lubricant per 100 parts by weight of the vinyl chloride resin is dissolved.

High density information record medium comprising a polymer material

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.

High density record including carbon black particles purified by

High density information signal recording media of an electrostatic capacitance type, in which an information signal is recorded as geometric variations. The medium consists of a conductive resin composition which comprises a vinyl chloride resin, carbon black particles and a silicone oil lubricant. The carbon black particles are treated with a silicone oil to have the oil coated thereon.

High density information record medium using carbon black particles

High density information records made of vinyl chloride resin compositions which comprise conductive powder and inorganic compounds in the form of powder having an antacidic action and a predetermined average size. By this, dropout defects in the information record can be suppressed to a significant extent. The inorganic compounds are selected from calcium hydroxide, basic aluminum magnesium carbonate hydrate and hydrotalcite.

High density information records made of conductive resin compositions

High density information records formed from conductive resin compositions which comprise a graft polymer obtained by subjecting vinyl chloride monomer to graft polymerization with a copolymer of ethylene and vinyl acetate having a content of vinyl acetate of not less than 35 wt % and a melt index up to 20 and prepared according to a solution polymerization technique. The conductive composition further comprises predetermined amounts of a conductive material and a lubricant of a specific type. The lubricant is an ester between aliphatic acid and alcohol having a hydroxyl value not larger than 15.

High density information records of an electrostatic capacitance type

A conductive resin composition comprising a specific type of graft polymer of vinyl chloride and a vinyl chloride/acrylic ester copolymer, and a conductive powder used in an amount of from 10 to 30 wt % of the graft polymer. The conductive composition is particularly useful as video or digital audio discs.

Conductive resin composition and information record

A high density information record of the electrostatic capacitance type comprising a record substrate on which signal information is recorded as geometric variations. The record substrate is made of a conductive resin composition comprising a vinyl chloride resin and a conductive powder. The vinyl chloride resin is obtained by suspension polymerization of starting vinyl chloride monomer in an aqueous solution of a water-soluble polymer suspension stabilizer from which insoluble organic matters with sizes over 10 .mu.m have been removed.

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 conductive resin composition comprising a thermoplastic resin, a conductive material, and a defined amount of a specific type of dimethylpolysiloxane lubricant having a degree of inhomogeneity of 1.0 to 1.3 and a degree of polymerization of 12 to 60.

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Yokohama, Japan

Toshiaki Hamaguchi