The replacement of conventional lubricants with esters is an alternative to provide a low environmental impact and at the same time excellent lubricity features, the high solubility of additives, good viscosity index, low volatility, and high thermal stability. Friction modifiers and antiwear/extreme pressure additives are extensively used to save energy and increase operational life in machine components. In this study, the lubricity of a Group IV base oil containing ester and various benchmark friction modifiers and/or antiwear/extreme pressure additives is measured to evaluate the influence of the ester on the tribological performance of the mixture components. The tribological performance is discussed based on the tabulation of the traction coefficient using a Mini-Traction-Machine and on the measurement of the specific wear rate from the wear scar of the experimental studies using an optical profilometer. In general, results show synergies between the ester and the additive formulations, reducing the wear rate to 75% and decreasing the traction coefficient a 20 to 50%, depending on the evaluated additive.

In recent years, one of the most concerning topics in healthcare is the constant exposure to ultraviolet (UV) light being the cause of numerous skin diseases. This issue created a keen interest in sun-care cosmetics, and particularly in sunscreens, since it has been proven to significantly reduce human skin disorders. Usually, sunscreens are formulated as emulsions with organic UV-absorbers dissolved in the oil phase; thus, the solubility of these UV-filters in the emollients is crucial. In this work we expose the properties of different emollients, correlating the chemical structure with the ability to dissolve organic UV-filters.

The high-pressure die-casting process is growing since it is a cost-effective solution in the production of lightweight parts for a variety of industries. Nevertheless, the harsh working conditions of the die lead to premature failing and poor quality of the produced parts. Lubricants are applied to cooling the die surface and create a protective film to minimize die wear. However, the high temperature of the die during the casting production makes it difficult for the lubricant to reach the die surface due to the Leidenfrost effect. In this study, the effectiveness of newly developed ester-based lubricants designed to address Leidenfrost phenomenon in high-pressure die-casting is evaluated at laboratory and pilot plant scale. The new lubricants are based on the same ester solution; however, one of them includes a specially formulated anti-Leidenfrost additive to optimize performance at the temperature ranges typically encountered in industrial aluminum high-pressure die-casting processes. The results show a correlation between lubricant heat-transfer capability and aluminum adhesion. Additionally, a pilot plant methodology for testing newly formulated lubricants has been established while the experimental methodology developed for assessing heat-transfer capability is validated as a rapid and cost-effective approach for evaluating lubrication alternatives for high-pressure die-casting applications. Finally, the efficiency of environmentally friendly ester-based lubricants for high-temperature applications has been demonstrated.