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AssigneeHitachi Maxell, Ltd.
InventorsYoshitake Kato, Kazuya Fukunaga, Akira Katami, Shinichiro Oda
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A data recording cartridge provided with a cartridge case and a recording medium accommodated therein, wherein the cartridge case is molded from at least one of the following materials: (1) composition of uniformly dispersed styrol resin and a polycarbonate resin; (2) composition of uniformly dispersed styrol resin and a nitrogen containing resin; (3) composition of uniformly dispersed styrol resin and an ester resin; (4) styrol resin styrene of which is partially substituted with .alpha.-methylstyrene; (5) styrene-maleic anhydride copolymer modified with rubber; (6) composition of polypropylene polymer containing an inorganic filler dispersed therein; (7) copolymer of N-substituted maleimide resin and styrol resin; and (8) composition of uniformly dispersed N-substituted maleimide resin and styrol resin.
A flexible magnetic recording medium composed of a non-magnetic base film having a magnetic thin film formed thereon, wherein said flexible magnetic recording medium has a maximum thermal contraction of 30 micrometers or less in the longitudinal direction when exposed for 96 hours in a test environment of 85.degree. C. and 40% RH.
A data recording cartridge provided with a cartridge case and a recording medium accommodated therein, wherein said recording medium is a disk-shaped flexible magnetic recording medium composed of a non-magnetic base film having a magnetic thin film formed thereon and rotationally accommodated in said cartridge case, wherein said flexible magnetic recording medium has a maximum thermal contraction of 30 micrometers or less in the longitudinal direction when exposed for 96 hours to a test environment of 85.degree. C. and 40% RH.
A method of manufacturing a flexible magnetic recording medium composed of a non-magnetic base film having a magnetic thin film formed thereon, comprising the steps of forming a magnetic thin film on said base film, causing said base film with said magnetic thin film formed thereon to be subjected during manufacturing to a heat treatment under conditions whereby the temperature is 90.degree. C. or more and the humidity is less than 20% RH for a period of time of from 48 to 72 hours, and then cooling to produce said flexible magnetic recording medium having a maximum thermal contraction of 30 micrometers or less in the longitudinal direction when maintained for 96 hours in a test environment having a temperature of 85.degree. C. and a humidity of 40% RH.
Dependencies are inferred from the claim text.