| 摘要 |
PURPOSE:To improve the surface smoothness and dispersibility of a magnetic layer by using a polymer obtd. by copolymerization of a polymerizable unsatd. sulfonic acid as a binder in the stage of providing the magnetic layer on a plastic film. CONSTITUTION:For example, 2-acrylamide-2-methyl propane sulfonic acid and butyl methacrylate are copolymerized as a polymerizable unstad. sulfonic acid, whereby a butyl methacrylate/2-acrylamide-2-methyl propane sulfonic acid copolymer is obtained, and said copolymer is used as a binder. 300 parts ferromagnetic iron powder, 3 parts dimethyl polysiloxane and 450 parts mixed solvents are mixed with 30 parts such binder and are dispersed therewith, whereby a magnetic coating is obtd. Such coating is applied on a polyester film to form a magnetic layer, whereby a magnetic tape is obtained. The magnetic layer formed in such a way has excellent surface smoothness and contributes to the formation of a magnetic recording medium having dispersibility and high degrees of packing. |
