Lubrication studies of aqueous mixtures of inversely soluble components

Phase and aggregational behavior of model metal working formulations of the inversely soluble type was studied with the aid of a new analytical tool. Correlations between these data and measured anti-wear performance data are discussed. The aim was to gain some insight into the mode of variation of the anti-wear effect with temperature and concentration depending on composition of inversely soluble formulations, despite the complexity of the systems. A comparison with a conventional synthetic metal working fluid indicated inherent advantages of inversely soluble concepts at elevated temperatures. Thus, as temperature is increased, as occurs in a friction contact, wear is more effectively mitigated with a suitable formulated inversely soluble system. Typically, as shown experimentally in this paper, the behavior is different from data observed with a conventional metal working fluid formulation. A substantial dependence of the anti-wear effect on the adsorption of boundary lubricating components is inferred from a study of correlation between monomer concentration and extent of wear. These experiments were conducted on surfactant concentrations exceeding critical micelle concentration (CMC) to various degrees. Findings also indicate a particular potential to optimize lubrication performance by exploiting synergetic effects observed in a combination of two different types of alkoxylated compounds. The investigated types of formulations offer particularly good prospects for effective contaminant removal without loss of active matter. This is favorable from an occupational health and environmental standpoint, due to the possibility to exchange biocides with mechanical means of microbial control and an improved potential for a long service life.