| 摘要 |
<p>PURPOSE:To enhance electromagnetic conversion characteristics and travel durability, by using a mixture of a copolymer of vinyl chloride-vinyl acetate-vinyl alcohol and coplymer of ethylene-vinyl acetate graft-polymerized with vinyl chloride for a binder. CONSTITUTION:A recording material is obtained by the following processes: Mixing 100pts.wt. gamma-Fe2O3, 10-22.5pts.wt. vinylchloride/vinyl acetate/vinyl alcohol copolymer, 2-12.5pts.wt. ethylene/vinyl acetate graft-polymerized with vinyl chloride, 2pts.wt. oleic acid, 0.5pt.wt. dimethylpolysiloxane; and 250pts.wt. butyl acetate; kneading and dispersing in a ball mill for 48hr; filtering with a filter; coating, e.g., 7mum thick polyethylene terephthalate film with the obtd. magnetic coating material using a reverse roll to 5mum dry thickness; subjecting orientation treatment by a magnetic field formed with a 1,000 gauss electromagnet before drying the coated layer; after drying, supercalender rolling the dried layer to smooth the magnetic layer.</p> |
