Document nNk4pJYX9Dprgg2e2xqYMVnM2

jcclcd refined base slock shipments for off-spcc color. Nowadays, re finer'! may nol be able lo maintain previous crude sources, and for- mulators have lo accept whatever refined stocks they can get--ifother specifications are met--and adjust their formulations to make the best of available stocks. As a result, lu bricant colors arc not necessarily the same, even though lubricating quality is identical. Another factor that may affect the familiar color of a lubricant is a change in additives. For example, lead naphthenate has been used to help gear oils resist extreme pres sure and impact loads. Recently, OSH A has urged that toxic or po tentially toxic substances such as lead naphthenate be removed from Many lubricant manufacturers use dynamometer stands such as this lo test industrial workplaces. ttear oils. Changing additives is not an easy process. Laboratory data on poten tial replacements are only sugges tive: performance is proven only after expensive and tedious field trials. Nevertheless, some synthetic extreme pressure agents, after field testing, are being phased in as re placements for the lead naphthenate. Since their color is not the same as the amber lead soap, they too can contribute to changes in tra ditional colois. The net result is that color has even less value than it ever did as a guide to lubricant quality. Shop per sonnel must be more alert than ever lo the requirements of the ma chinery they service and qualities of the oils they pour. an additional incentive lo develop hsbestos-Trec compositions. The application for solid lubri cants islts a friction modifier. ConvcntionaTfriction materials have up to 15 components. Asbestos is by far the major component, compris ing some 60 to SOCf of friction mate rials. Phenolic resin is typically used as a hinder. Various additives are incorporated--more on the basis of art than scientific knowl edge. Other commonly used additives include ground rubber, for elasticity; coal, as a cheap source of graphite; gilsonite. as a friction modifier; and zinc oxide, as a corro sion inhibitor. Asbestos is very difficult to re An appreciable increase in the coefficient of friction at higher tem peratures. (Pads frequently get to 200+F, and reach 400to 500F with prolonged downhill braking. Under severe braking, pads reach lOGO'F, red heat.) >2 High pad wear. Unacceptable noise. Dow Coming Corporation, Mid land, Michigan, has developed a new product, "Lubolid", to help solve these problems. Now in use, Lubolid is a mixture of molybdenum disulfide, and other materials 'for use as a friction modifier in clutch and brake friction materials. According to George V. Kubczak, Development Engineer at Safer brakes and clutches -- with lubrication Changes in industrial and au tomotive friction materials are ~cfmTging applications for sol id hi hi'ieanls such as molybdenum disul fide. This surprising application of lubricants in friction materials comes as a result of environmental pressures. place. especially as a major compo Dow Coi ning, its benefits tire: nent, because it uniquely combines A more constant coefficient of a high, stable coefficient of friction friction. with an almost ideal balance of Reduced disc wear. abrasiveness and lubricity. "Reduced noise. Scmimctallic compositions, first! Tfic principal competitive male- used in Europe and Japan, are now! rial for this application is graphite. coming into use hcic. In these com-t-- "Graphite has useful properties to positions, also called `'resin-mots", 2(!00F; its cost depends on the spe wool or shavings from steel or brass cific grade used. Ilowever, graphite replace asbestos as the fibrous requires moisture for good Asbestos is now a major conipo- component. The resin-mets, how lubricity--which may lead lo corro ncitl of friction materials, hntindns- ever. have problems; sion prohlems. Also, any moisture try anticipates an JEPA-ban -on-its "Morning sickness" -- inade initially present is lost when pad use. Possible liability jM|its_may:.JscJ quate braking with cold starts. V temperatures reach 2l2Por higher. PTOMU80 I i i 4W&-. m-w.-- f" ' :S:a. SCI 02193