Flexible magnetic recording media having superior peel strength
AssigneeHoechst Celanese Corporation
InventorsJohn M. Heberger, Russell S. Foxhall
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Abstract
A flexible magnetic recording media having superior peel strength is disclosed. The magnetic recording media comprises a primer coated polyester film which has been overcoated with a coating comprising ferromagnetic particles dispersed in a polymeric binder. The primer coating is preferably sodium oleate which has been in-line coated onto polyethylene terephthalate film. The ferromagnetic particles are preferably chromium dioxide particles. The polymeric binder is preferably a polyurethane reaction product of (A) a hydrolytically stable difunctional alcohol, (B) a chain extender, and (C) an aromatic diisocyanate.
Claims26
A magnetic recording media having superior peel strength comprising
- (i) an oriented polyester film,
- (ii) a primer coating on at least one side of said film consisting essentially of a water-soluble alkali metal salt of an unsaturated fatty acid having from 10 to 18 carbon atoms,
- (iii) a ferromagnetic coating applied over said primer coating, said ferromagnetic coating comprising ferromagnetic particles dispersed in a polymeric binder;
- said primer coating being present at a weight effective to improve the adhesion of said ferromagnetic coating to said film.
A magnetic recording media produced by the process comprising
- (i) extruding a substantially amorphous polyester resin in sheet-like form and subsequently cooling said resin to form cast polyester sheet,
- (ii) subsequently orienting said polyester sheet in the longitudinal direction, thereby forming monoaxially oriented polyester film,
- (iii) coating said sheet with an aqueous solution consisting essentially of a water-soluble alkali metal salt of an unsaturated fatty acid having from 10 to 18 carbon atoms;
- (iv) subsequently orienting said monoaxially oriented polyester film in the transverse direction, thereby forming biaxially oriented polyester film,
- (v) heatsetting said biaxially oriented polyester film,
- (vi) subsequently overcoating said polyester film with a ferromagnetic coating composition comprising
- (a) a solvent selected from the group consisting of tetrahydrofuran, methylethylketone, methylisobutylketone, and cyclohexanone,
- (b) ferromagnetic particles,
- (c) a pre-polymer,
- (vii) curing said pre-polymer to produce a coating comprising ferromagnetic particles dispersed in a polymeric binder.
A magnetic recording media produced by the process comprising
- (i) extruding a substantially amorphous polyester resin in sheet-like form and subsequently cooling said resin to form cast polyester sheet,
- (ii) coating said sheet with an aqueous solution consisting essentially of a water-soluble alkali metal salt of an unsaturated fatty acid having from 10 to 18 carbon atoms;
- (iii) subsequently orienting said polyester sheet in the longitudinal direction, thereby forming monoaxially oriented polyester film,
- (iv) subsequently orienting said monoaxially oriented polyester film in the transverse direction, thereby forming biaxially oriented polyester film,
- (v) heatsetting said biaxially oriented polyester film,
- (vi) subsequently overcoating said polyester film with a ferromagnetic coating composition comprising
- (a) a solvent selected from the group consisting of tetrahydrofuran, methylethylketone, methylisobutylketone, and cyclohexanone,
- (b) ferromagnetic particles,
- (c) a pre-polymer,
- (vii) curing said pre-polymer to produce a coating comprising ferromagnetic particles dispersed in a polymeric binder.
Dependencies are inferred from the claim text.