The Preparation of a Polyurea Grease Using mPAO 65 and Preformed Diurea

摘要

This paper provides a simple example of the use of mPAO 65 (metallocene polyalphaolefin oil, kinematic viscosity = 65 cSt at 100℃) and a preformed polyurea thickener to produce a polyurea grease. The ease of manufacturing using a preformed thickener is highlighted as well as the excellent properties that are obtained from the mPAO base oil. NLGI grade 2 grease was prepared in the absence of additives and therefore represents a base grease that provides a starting point for further formulation. The low temperature properties of this base grease are an advantage even though polyurea greases are typically known for high temperature advantages over lithium and calcium types of thickener systems. Rheological data clearly demonstrates the superior behavior of this mPAO 65 based grease. Between -30 and -40℃ viscosity was significantly lower than a polyurethane grease formulated with ISO 220 mineral oil. Dropping point (> 260℃), oxidation induction time (14.49 min at 180℃) and temperature for 5% weight loss (294℃) were impressive at high temperatures. Therefore, this grease may be suitable for formulations intended for applications over a wide temperature range. In addition, the apparent viscosity data suggest that this grease has potential to help to prevent fretting corrosion.