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AssigneeFuji Photo Film Co., Ltd.
InventorsKiyomi Ejiri, Hiroaki Araki, Hiroshi Hashimoto
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A magnetic recording medium improved in electromagnetic characteristics, running durability and running properties is disclosed, comprising a non-magnetic support and at least one magnetic layer formed thereon, said magnetic layer having a ferromagnetic powder dispersed in a binder, wherein said magnetic layer contains at least one member selected from the group consisting of an aromatic phosphoric acid or a derivative thereof, an aromatic phosphonic acid or a derivative thereof, and an aromatic sulfonic acid or a derivative thereof, and wherein said ferromagnetic powder has a pH of at least 7, and said binder is a vinyl chloride copolymer having an epoxy group and a hydroxyl group attached to an alkyl chain group. Also, a method for producing a magnetic recording medium is disclosed which comprises the steps of kneading and dispersing a ferromagnetic powder having a pH of at least 7, at least one member selected from the group consisting of an aromatic phosphoric acid or a derivative thereof, an aromatic phosphonic acid or a derivative thereof, and an aromatic sulfonic acid or a derivative thereof, and a vinyl chloride copolymer having an epoxy group and a hydroxyl group attached to an alkyl chain group, together with a solvent; and then optionally adding at least one additive thereto, and mixing to prepare a magnetic coating; and then applying the resulting magnetic coating to a non-magnetic support; drying, calendering and then heat treating.
A magnetic recording medium comprising a non-magnetic support and at least one magnetic layer formed thereon, said magnetic layer having a ferromagnetic powder dispersed in a binder, wherein said magnetic layer contains at least one member selected from the group consisting of an aromatic phosphoric acid or a derivative thereof, an aromatic phosphonic acid or a derivative thereof, and an aromatic sulfonic acid or a derivative thereof, and wherein said ferromagnetic powder has a pH of at least 7, and said binder is a vinyl chloride copolymer having an epoxy group and a hydroxyl group attached to an alkyl chain group.
A method for producing a magnetic recording medium which comprises the steps of kneading and dispersing a ferromagnetic powder having a pH of at least 7, at least one member selected from the group consisting of an aromatic phosphoric acid or a derivative thereof, an aromatic phosphonic acid or a derivative thereof, and an aromatic sulfonic acid or a derivative thereof, and a vinyl chloride copolymer having an epoxy group and a hydroxyl group attached to an alkyl chain group, together with a solvent, and then optionally adding at least one additive thereto, and mixing to prepare a magnetic coating, applying the resulting magnetic coating to a non-magnetic support, drying the coating applied to the non-magnetic support, and thereafter subjecting the coating to a calender treatment, and then heat treating at 50.degree. to 90.degree. C. within 30 hours.
Dependencies are inferred from the claim text.