OSP-New Group V Base Fluid for Manufacture of Sulfonate Greases Govind Khemchandani, Ph. D.1, Perry Byrd2, & Jeff St. Aubin3 ἀ e Dow Chemical Company Freeport, Texas 77541, USA gvkhemchandani@dow.com
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INTRODUCTION
Oil-soluble polyalkylene glycols (OSPs), a new group V base fluid derived from downstream derivatives of butylene oxide (BO), have been designed to provide good solubility in API (American Petroleum Institute) Groups I to IV base oils [1-4]. ἀi s new class of group V base fluid now can be used as a co-base oil in hydrocarbon base fluids, which is not possible with conventional polyalkylene glycols (PAGs). OSPs have high viscosity indices (VI), good low temperature properties, low coefficients of friction and low aniline points. OSPs help to improve the deposit control of compositions derived from mineral oil when used as co-base oil. A combination of low aniline point and deposit control ability of OSPs were leveraged to make lithium and lithium complex greases [5-7]. Recent innovations in equipment design have resulted in components operating at higher speeds, producing increased power output, and as a direct result, operating at
higher continuous temperatures. Under these severe conditions, protecting equipment is stretching the limits of conventional grease technology [8]. ἀ ese new tribomachines create new opportunities for grease formulators to use their skills in developing products based on new base fluids, thickeners and superior additive systems. Without change in base stocks or thickeners, avenues for performance advances become limited [9]. ἀ e quest for better performing synthetic grease prompted the authors to develop ‘over based calcium sulfonate (OBCS)’ grease derived from OSP base stock and super sulfonate thickener.
OBJECTIVE
Conventional PAGs are used for making greases with inorganic and organic thickeners for specific applications [10]. However, Calcium Sulfonate Complex Grease is suitable for a wide range of applications, since it has various excellent inherent properties in the sulfonate matrix [11]. Basic technology for the - 20 VOLUME 79, NUMBER 2
Mid-South Sales, Inc Jonesboro, Arkansas 3 Chemtool Incorporated Rockton, IL 2
manufacture of Calcium Sulfonate Complex Grease was established in early 1980’s. Improvements in the formulation and manufacturing process have been made thereafter and one can find several patents and reports [12, 13]. However, Calcium Sulfonate Grease was included in ‘NLGI Global Grease Survey’ as a separate category [14] in year 2000. Since then many excellent research papers have appeared describing their use in steel mills, automotive and construction heavy equipment [15]. In the components of grease, base oil accounts for about 75-95 percent, meaning that the performance of grease is largely determined by the characteristics of base oil. ἀ erefore, grease cannot be any better than its base oil [16]. Consequently, before selecting any base oil, its characteristics should be examined in detail for its desired application. References 1 to 6 describe many excellent characteristics of OSPs for grease making. Further continued research on OSPs has indicated novel
