The Development of More Environmentally Considerate Greases By: Gareth Fish, PhD CLS CLGS The Lubrizol Corporation
Abstract
Reduced environmental impact through the choice of suitable greases has become an important consideration of many end users. Emerging government legislation and policies place emphasis on product life cycle impact upon the future protection of global natural resources. Programs in Europe and North America have prompted research and development of new grease additive packages and component technologies. There is greater demand for environmentally considerate base fluids and thickeners. Recent technology developments have enabled biobased and eco-considerate grease products to achieve a high level of performance directed toward total loss applications including farming, forestry, marine and mining. Environmentally considerate greases require carefully selected base fluid(s) meeting specific biodegradability or bio-based criteria while providing an acceptable level of performance to the end user. The base fluids can be either refined vegetable oils, estolides or synthetic
esters. Biodegradable polymeric esters to boost the viscosity of the base fluid can be included. Thickener selection is also important in creating environmentally considerate greases. Simple thickeners can be prepared from pre-formed soaps such as calcium or lithium 12-hydroxystearate, or using inorganic thickeners such as clays or silica. Both simple lithium and high temperature lithium complex greases can now be prepared directly using anhydrous lithium hydroxide dispersions. After a base fluid and thickener have been chosen, the next step is to select an additive that offers the performance desired without negatively impacting the environment. We reviewed current ecological and toxicological data and were able to create a variety of environmentally considerate grease formulations.
Introduction
In 1980, the Comprehensive Environmental Response, - 44 VOLUME 80, NUMBER 3
Compensation and Liability Act (CERCLA) was passed which established the setting up of process for identifying, containing and cleaning up contaminated toxic waste sites in the USA(1). It empowers the US Environmental Protection Agency (EPA) and its supporting organizations to control such sites and to compel responsible parties to perform cleanups or reimburse the government for EPA-lead cleanups. CERCLA is commonly known as “superfund”. The cost of this process is extremely high and it has been recognized that it is better to avoid pollution rather than pay for it to be cleaned up. According to EPA published figures (1) this has led to much improvement in the general environment and the successful re-use of once significantly contaminated land. At the 1991 ELGI Annual Meeting (2), it was reported that in 1990 the European Commission had carried out a study into automotive greases and had concluded that more than 4000 tonnes of grease was lost into the environment from trucks. The basis for the calculation
