The effects of inhibitors and contaminants on the stability of magnetic tape lubricants

Abstract

The oxidative stability of fatty acid esters typical of those used as lubricants in magnetic tapes and floppy discs has been evaluated in the Penn State microoxidation test. The stability of these lubricants can be influenced adversely by acid type degradation products, as well as by chemical interaction with the magnetic oxides used in the tape coating. The life of the lubricant in the presence of these oxides and contaminants can be increased significantly in this thin-film test by the use of oxidation inhibitors and surface deactivators (surfactants). The interaction of the lubricant, oxygen, and the magnetic oxides actually produces soluble organic-metal products. Evaporation also appears to be a problem in the life of tape lubricants. The use of less volatile lubricants made with the same fatty acid shows improved life in the microoxidation tests. Storage of the tapes under accelerated conditions shows that the liquids, including the lubricant are affected after moderate storage times. The effect of humidity appears to be more significant than the oxidative effect suggesting hydrolysis of the esters as a major factor in the overall tape stability. © 1988 Taylor & Francis Group, LLC.