| 摘要 |
<p>Magnetic recording material comprises a substrate coated with a magnetic layer consisting of (a) a magnetic powder and (b) a binder comprising a polymer (I) with -SO3Na gps. and a polyurethane prepolymer (II). The (I) is pref. a polyester contg. -SO3Na gps. The binder may also contain other polymers such as thermoplastic polyurethanes, nitrocellulose, vinyl chloride-vinyl acetate copolymers, polyesters contg. no -SO3Na gps., etc. The magnetic layers can be cured e.g. with a polyisocyanate crosslinking agent. Use of polyesters contg. -SO3Na gps. in the binder compsn. promotes good dispersion of the magnetic component without the necessity for incorporating additional surface active agents, as in prior art materials. The prods. are esp. useful as video recording tapes with excellent physical and electromagnetic characteristics, including good wear and durability, good frequency response and high signal/noise ratio.</p> |
