Disk type magnetic recording medium and process of manufacturing the same
AssigneeKonica Corporation
InventorsIsamu Michihata, Hideki Murata, Katsuyuki Takeda, Nobuyuki Sekiguchi, Syozo Kikugawa
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Abstract
A magnetic recording medium and a manufacturing process thereof are disclosed. The medium comprises a magnetic layer containing a binder, chromium oxide having an average particle size within the range of 0.3 to 0.5 .mu.m and a metal magnetic powder, wherein the binder comprises a polyurethane resin having a polar group selected from the group consisting of --SO.sub.3 M, --OSO.sub.3 M, --COOM, --PO (OM), and --OPO(OM).sub.2 wherein M represents a hydrogen atom or an alkali metal.
Claims10
A magnetic recording medium comprising a non-magnetic support having provided thereon, a magnetic layer containing a first binder, chromium oxide having an average particle size of 0.3 to 0.5 microns, and a metal magnetic powder comprising iron and aluminum, wherein said first binder comprises:
- (1) a polyurethane resin having a polar group selected from the group consisting of SO.sub.3 M, OSO.sub.3 M, COOM, PO(OM).sub.2, and OPO(OM).sub.2, wherein M represents hydrogen or an alkali metal;
- and
- (2) a polyvinyl chloride resin having an epoxy group and a polar group selected from the group consisting of SO.sub.3 M, OSO.sub.3 M, COOM, PO(OM).sub.2, and OPO(OM).sub.2, wherein M represents hydrogen or an alkali metal.
A process for manufacturing a magnetic recording medium comprising a support, a magnetic layer on said support and containing a first binder, a second binder, chromium oxide having an average particle size of 0.3 to 0.5 microns, and a metal magnetic powder, said process comprising;
- (a) forming a first dispersion by dispersing said metal magnetic powder in said first binder, said first binder comprising;
- (1) a polyurethane resin having a polar group selected from the group consisting of SO.sub.3 M, OSO.sub.3 M, COOM, PO(OM).sub.2, and OPO(OM).sub.2, wherein M is hydrogen or an alkali metal, and
- (2) a polyvinyl chloride resin having an epoxy group and a polar group selected from the group consisting of SO.sub.3 M, OSO.sub.3 M, COOM, PO(OM).sub.2, and OPO(OM).sub.2, wherein M represents hydrogen or an alkali metal;
- (b) dispersing said chromium oxide in said second binder to prepare a second dispersion;
- (c) adding said second dispersion to said first dispersion to form a magnetic coating composition;
- and
- (d) coating said magnetic coating composition on said support.
Dependencies are inferred from the claim text.