Speaking in March at the UNITI Mineral Oil Technology Conference in Stuttgart, Germany, Axels Willem Smets described a market dominated by technology that is more than half a century old. Most end users opt not to use newer technologies because they place more value on approvals from original equipment manufacturers and on their own experience.

The grease market as such includes a very wide spectrum of multipurpose products, whose end users rely on security more than innovation, Smets said. These users swear on the use of lithium-thickened, mineral oil based products containing solids and/or mild extreme pressure additives.

Most greases consist of three basic parts: a base stock that provides some lubricity; a thickener that maintains a semi-fluid state; and chemical additives that enhance performance properties. Smets argued that there has been little evolution with two of those parts. According to a 2011 survey by the U.S.-based National Lubricating Grease Institute indicating that more than 90 percent of the grease consumed in the world is formulated with conventional mineral oil base stocks, rather than synthetics. The survey also found that more than 75 percent of greases are formulated with lithium soap-based thickeners or lithium complex thickeners, both of which were first patented in the 1940s.

So much of the grease in use is based on a concept which is 60 years old, said Smets, who serves from the Netherlands as Axels OEM coordinator.

Without change in base stocks or thickeners, he said, avenues for performance advances become limited. The improvement of greases has centered on the search for additives to extend capabilities of the basic product.

There are indeed companies working to improve additive technology, but Smets contended that several factors hamper progress. For one thing, demand for greases is but a fraction of the demand for lubricating oils, so research and development for greases receive less attention. Many greases additive systems were in fact developed for gear oils, he said.

Physical and chemical issues pose bigger problems. Many additives, especially those meant to protect against extreme pressure, function by interacting chemically with the surfaces of components. It goes without saying that these additives need to reach those surfaces, but they may have difficulty getting there. For one thing, extreme pressure is typically caused by high loads, elevated temperatures or low speeds – all of which tend to reduce the lubricating film. That means less grease between components, and less grease means fewer additives.

Moreover, soap thickeners, including those based on lithium, usually are much more highly polar than the additives. Polarity causes attraction to metal surfaces, so there is competition for that space between thickeners and additives, and thickeners usually win.

Grease formulators have tried a couple ways to escape this dilemma. One was to use performance-enhancing additives that bond with soaps so that the latter serve multiple purposes instead of just thickening. Additives in these products have no trouble reaching components because the thickeners carry them there. The other concept is to use thickeners such as polymers that are non-polar. Without thickener molecules crowding component surfaces, additives have a much better chance to reach the components and begin functioning.

One example of a functional soap, Smets said, is calcium sulfonate complex thickeners. Greases containing them were introduced years ago, but initially they did not provide good lubricity at ambient or low temperatures because formulas needed a high portion of thickener. This limited oil separation, which is needed in order for the grease to spread.

Now, Smets said, there are more calcium sulfonate producers on the market, and new technologies and manufacturing methods have been introduced. Performance advances have allowed grease formulators to reduce the portion of thickeners by almost 50 percent, significantly improving lubricity at low and ambient temperatures.

Characteristically these greases show a remarkable combination of corrosion protection, water resistance, high-temperature performance and load-carrying capacity, all in one product, Smets said.

He also cited two other functional soap technologies developed by Axel, which is based in Nol, Sweden. The first is dubbed Alassca, an acronym for acetic lithium azelaic stearic sacrosylic calcium, which covers some of its ingredients. Axel declines to further discuss its contents but says it developed the technology in an effort to combine the benefits of lithium complex and calcium complex thickeners.

According to Smets, Alassca complex greases have a combination of extreme load-carrying capacity and good lubricity across a wide range of temperatures, making them well-suited for use in open gears. Alassca also eliminates the need for bitumen or black solid lubricants such as graphite or molybdenum disulfide.

The second functional soap from Axel is lithium-bismuth complex. Bismuth was already known to be very effective at protecting against extreme pressure, otherwise improving antiwear performance and inhibiting corrosion inhibitor, but Axel found it could amplify these benefits by making the bismuth part of the thickener rather than having the base stock carry it. Smets explained that the company commissioned a bearing fretting test on two greases – one with lithium-bismuth complex thickener and the other with bismuth in base oil. Conducted on a Ripple test rig, the test generated significantly less wear on the bearing lubricated by the grease with the functional soap. That grease also required much less torque during the test.

For all of the performance these functional soaps have demonstrated, the market has been slow to use them. Of the three mentioned above, calcium sulfonate complex greases have made the biggest in-roads but still accounted for only 1 percent of global demand. Consumption of Alassca and lithium-bismuth greases is even lower, though Smets added that Alassca has gained recognition as a reference product. Lithium Bismuth Complex is still relatively new, and it might take some time before the market recognition for this technology evolves, he said.

Smets said the markets inertia against use of new technologies is understandable.

The end user opts for security, he said. Their main concern is not to jeopardize their equipment, unless theres a very, very good reason for it, and theyre quite right to do so.

Any dynamic for detailed adjustment in lubrication schemes therefore has to come from the OEM side. [But] it is strange to notice that only few [OEMs] are willing to depart from patterns which have existed for decades, particularly when it comes to greases.

He was quick to add that some end users do look for innovation.

Its very tempting to see the market as uniform, but that is not accurate, he said. Some players couldnt care less about the specific properties of a thickener type, as long as the product is supplied correctly and meets the agreed specifications in a consistent and reliable way, without deviations. Others have an insatiable appetite for anything new, whether it concerns genuine performance parameters of a product or just its color or a novel packaging type.

The latter group may be much smaller, but Smets said it carries enough weight to prod grease formulators to continue the search for better technology.

When looked at purely from an accounting perspective, [cutting back on research and development] would probably not be a bad idea, he said. However, when a company works around one particular product, it only requires a few passionate enthusiasts to discover vast areas for improvement. With those fanatics in place, we just wont be able to stop coming up with innovative ideas on lubricating greases.