Less can be more

Using naphthenic oil of high viscosity and novel nanoparticles, Nynas’ specialists make leaner high-performance lithium complex grease formulated with fewer components, potentially enabling lower manufacturing costs.

Mehdi Fathi-Najafi is Chief Specialist at Technical Development and Support, Nynas Naphthenics. He joined Nynas in 2008.

A study carried out by Nynas, and Nanotech Industrial Solutions Inc. (NIS) demonstrates that high-performance grease formulations can be made using fewer components with excellent performance for example in four-ball tests. In other words, less can be more - provided that the right ingredients are used in formulations.

“Our findings emphasise the efficiency of using high viscosity naphthenic oil in lithium complex greases. Not only does this contribute to the potential for leaner grease formulations with excellent yields, it also creates almost perfect conditions for the use of nanoparticles, such as fullerene-like inorganic particles of tungsten disulphide (IF-WS2), resulting in excellent high load carrying capacity along with low wear in the tribological contacts,” says Nynas’ chief specialist Mehdi Fathi-Najafi.

The study compared the performance of lithium complex grease made with different base oils, of varying viscosity, with special focus placed on the high viscosity naphthenic oil NYNAS® T600, see Table 1.

“It is well known that the use of naphthenic base oil can reduce the thickener content. However, in this study we were able to establish a direct correlation between the viscosity of the naphthenic base oil and the thickener content, the degree of oil separation, and the mobility of the grease at -20°C,” says Mehdi Fathi-Najafi.

In addition, the study looked at the effectiveness of solid additives, comparing the performance of conventional solids such as molybdenum disulphide with that of novel nanoparticles (IF-WS2). Because of their nano size and large surface area, even very limited concentrations of IF-WS2 particles will make a difference in formulations, offering better protection against wear, friction, and extreme pressure.

As shown in the figure, the response of these nanoparticles was significantly greater in Grease A, pointing to the synergism between the NYNAS® T600 and this type of solids.

“Treat rates with these nanoparticles are an order of magnitude lower than when conventional platelet particles are used as solids in grease formulations” explains Mehdi.

Further reading

Time to regroup

Nynas is going even further to help customers overcome the shrinking supplies of Group I oil.

Grease lubrication of roller element bearings

Our knowledge of what actually happens when grease lubrication is used has increased dramatically in the last ten years. The latest research gives a new view on how to formulate grease to optimise its effect under different conditions, not least when it comes to adapting the grease to the temperature a machine operates at.

Naphthenic oil gives grease a competitive edge

With a viscosity of 150 cSt, the BT 150 from Nynas' Harburg refinery is an excellent choice for grease manufacturers. Offering an alternative to, for instance, the 750SUS oil used in the US grease market, this new naphthenic oil promises to save money and improve performance.