Pollution prevention in the magnetic tape industry: Waterborne coating formulations for video tape manufacture

A waterborne magnetic tape coating formulation was designed and used to prepare experimental magnetic tape samples in a pilot coating trial. The formulations contained a blend of a water-dispersed polyester and an ethylene/vinyl chloride copolymer emulsion, cross-linked with melamine-formaldehyde to give tensile properties (tensile strength 8.69 MPa and Youngʹs modulus 245 MPa) that were comparable to a standard solvent-based binder composition. The pilot tape trial used existing processing equipment, including calendering and slitting. The tape had good magnetic properties and excellent adhesion between the pigmented magnetic layer and the base film, easily exceeding the 8 mm helical scan tape standard of 0.96 N peel force. An economic impact analysis for the case of using our waterborne video tape coating process in a conventional tape manufacturing plant showed a significant decrease in costs for adopting the waterborne process.