The Structure and Properties of a Biodegradable Grease with a Mixed Dispersion Medium and a Heterogeneous Lithium–Calcium Dispersed Phase

The features of the structure formation of a biodegradable grease with a mixed dispersion medium (a mixture of rapeseed and mineral group III according to American Petroleum Institute (API) standard oils) and a heterogeneous lithium–calcium soapy dispersed phase are considered. An original process technology is used for the manufacturing of the grease, which makes it possible to minimize the negative effect of water and high temperature on the vegetable component of the dispersion medium during the thermodeformation action on the reaction mass. The formed structure of the dispersed phase of this grease is a combination of both relatively thin fusiform fibers of lithium 12-hydroxystearate with a length of 10–25 μm and a diameter of 2–5 μm and larger lamellar strips with a length of 20–40 μm and a thickness of 5–10 μm formed by the salts of calcium 12-hydroxystearate. This provides the optimum combination of the rheological and tribological properties of the grease, in particular, the increase in the water resistance and shear resistance in comparison with simple lithium greases and increase in the dropping point in comparison with simple calcium greases. The biodegradability of the lamellar lithium–calcium grease is 89%. The formulation and production process of an OIMOL CL BIO biodegradable lamellar lithium–calcium grease for general technical purposes are developed, and its industrial production is organized.