| 摘要 |
<p>1,153,316. Magnetic structures. GEVAERTAGFA, N.V. 22 Aug., 1967 [30 Aug., 1966], No. 38553/66. Heading H1H. A magnetic recording material comprises a coating on a base of magnetic particles dispersed in a binder, and petrolatum as lubricant in or over said coating. Petrolatum is defined as a mixture of semi-solid hydrocarbons, mainly C20-C22, melting at 34-54‹ C., obtained from the petroleum fraction boiling above 280‹ C. Preferably, the fraction of petrolatum which is soluble in binder solvents, e.g. dichloroethane, M.E.K., or THF, is used. 0À2-5% petrolatum, by wt. of the particles, may be used. The particles may be acicularγ-Fe 2 O 3 (0À2-2 Álong, 0À02-0À6 Áwide), Fe 3 O 4 , CrO 2 , Fe-Ni-Co alloy (size 30 mÁ.), or a metal or ferrite, and the coating may contain 65-85% by wt. of the particles. The binder may be polyvinyl chloride or acetate, copolymers of vinyl alcohol with vinyl acetate, butyral or chloride or with vinylidene chloride, or of vinylidene chloride with acrylonitrile, a partially hydrolysed copolymer of vinyl chloride and acetate, polybutylacrylate, polyurethanes, or isocyanate-modified polyesters or polyesteramides (e.g. prepared from ethylene glycol, adipic acid, and ethanolamine, and modified with hexamethylene diisocyanate). The base may be a disc, drum or tape of oriented polyethylene terephthalate or P.V.C., cellulose triacetate, paper, glass, or metal, and may be 0À01-0À06 mm. thick.</p> |
