Sunflower based biodegradable lubricants
Environmental concerns have recently, in the last few years, created an intense research effort in the field of biodegradable lubricants. While, the usual mineral or synthetic lubricants have the advantage of operating under pretty much any desired engine condition; they also present a serious environmental source of pollution. Different types of biodegradable lubricants have already been developed in order to address the above problems. The initial trials produced lubricants that were mainly based on synthetic esters and natural materials like rapeseed oil. These lubricants, which dispensed with the serious problem of environmental pollution however, leave economic concerns unanswered. In order for a biodegradable, but synthetic lubricant to fulfil technical requirements, its production is finally 6 times more expensive than the traditionally used mineral oils, which is a considerable expense when a normal tank contains 0.8 tonnes of oil for earthmoving vehicles. Vegetable oils like rapeseed based hydraulic oils have also been explored but present some drawbacks such as, time dependant viscosity at low temperatures, hydrolytic and oxidation stability problems and difficulties when filtering. Their use is, therefore, limited to applications that require lower technical performance. The current project has designed and tested two innovative biodegradable lubricants based on re-growing industrial crops, especially suitable for earth moving machines. These new lubricants are produced from sunflower oils and their performance is much better than that of rapeseed based lubricants. Extensive tests have been carried out in single machine components, namely those of an excavator. The hydraulic lubricant is thus designed to function appropriately in both warm and cold countries. The research project apart from the two hydraulic lubricants has also developed a gear oil. The new lubricants are 90% biodegradable with low toxicity. Their hydrolytic behaviour is very good. Only for Countries with low temperatures, is the addition of synthetic lubricants is still necessary for stabilising the oil. The slight increase in price of these environmentally friendly lubricants will be compensated with larger time intervals between changes of the engine's lubricants. During the tests performed by the project partners the oil for the hydraulic system was changed every 2,000 hrs of operation. Many applications involve earth-moving machines within industries such as agriculture, construction and transport. Therefore, a number of potential users exist for lubricants that are not only biodegradable but also fulfil the necessary technical requirements. Project partners also wish to exploit the possibility of developing sunflower based lubricants for other areas of application, including machine tools, automotive and aeronautic machines.
