POLLUTION PREVENTION IN THE MAGNETIC-TAPE INDUSTRY - WATERBORNE COATING FORMULATIONS FOR VIDEO TAPE MANUFACTURE

A waterborne magnetic tape coating formulation was designed and used t o 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 mela mine-formaldehyde to give tensile properties (tensile strength 8.69 MP a and Young's modulus 245 MPa) that were comparable to a standard solv ent-based binder composition. The pilot tape trial used existing proce ssing equipment, including calendering and slitting. The tape had good magnetic properties and excellent adhesion between the pigmented magn etic layer and the base film, easily exceeding the 8 mm helical scan t ape standard of 0.96 N peel force. An economic impact analysis for the case of using our waterborne video tape coating process in a conventi onal tape manufacturing plant showed a significant decrease in costs f or adopting the waterborne process.