The global grease market has seen a shift in the use of alternative thickeners in the past few years. The volume made with conventional lithium has continued to ebb, while the amount made with lithium complex, calcium sulfonate and polyurea thickeners has gradually increased.

Global grease production has remained relatively stable over the past decade, reaching just above 1.13 million metric tons in 2017, a 0.4 percent decrease from the year before on a reported basis, according to figures provided in the National Lubricating Grease Institutes latest grease production survey.

Conventional lithium soap thickener accounted for around 54 percent of worldwide grease production in 2017, down from 56 percent in 2014. Lithium complex thickeners made up nearly 21 percent of global output in 2017, up from about 19.5 percent in 2014.

Indian Market Perspective

Production of lithium soap thickeners in India has steadily dropped to 75 percent of total output in 2017 from 82 percent in 2014. Meanwhile, the share of lithium complex soap has seen the most notable increase and accounted for 9 percent of the countrys grease production in 2017. These greases combined dominate the Indian market with an 84 percent share.

Speaking at the annual meeting of NLGIs Indian chapter in February in the city of Guwahati, Bela Toth, lubricant export sales manager at Hungary-based Mol-Lub Ltd., said the Indian grease market is traditionally a monoculture comprising lithium- and lithium complex-based greases. This, Toth said, exposes domestic manufactures to supply risks in case of lithium shortage.

Lithium has several uses but the biggest and fastest growing demand comes from makers of lithium-ion batteries for smartphones, laptops and electric vehicles. In recent years, there has been a buying frenzy for lithium, dubbed white petroleum for its silver-white color and desirability, as battery makers in the United States, Europe and China vie to secure directly contracted supplies from mining companies for a natural resource that is not yet traded on conventional metals exchanges.

Electric cars are popping up everywhere and theres massive investments into the auto industry, [which] is eating up pretty much all the lithium sources around the globe, Toth said.

The potential shortage, coupled with higher lithium prices and the high dependence on a single type of grease, could create a vulnerable supply scenario, Toth cautioned. Indian manufacturers should look at an alternative option to lithium and lithium complex greases, he added.

Aluminum Alternative

Aluminum complex grease is one such alternative, as it could bring application benefits in selected areas and offer new business opportunities to Indian manufacturers, Toth said. These benefits include a high dropping point (the temperature at which a grease become liquid), excellent water resistance, good shear stability (a greases ability to maintain consistency when worked), very good oxidation stability, excellent pumpability, chemical resistance, non-toxicity and heat reversibility (the ability of grease to return to normal consistency after repeated heating and cooling), he claimed.

Application areas where both water resistance and heat reversibility are important could include the steel, paper, food and automotive industries, as well as for mining and agricultural machines and marine applications, Toth said.

Aluminum complex grease accounted for 3 percent of total global grease production in 2017, according to the NLGI survey. Toth said this figure belies regional variations, with North America, Europe and Asia-Pacific accounting for much of that demand.

Also according to NLGI, India recorded production of around 81,587 tons of grease in 2017, with the share of aluminum complex grease in total production less than 1 percent.

Toth said the share of aluminum complex grease in Indias total grease output remains low but there is ample opportunity for local manufacturers, assuming the thickeners share in the countrys production reaches 3 percent, in line with global grease output. This, he added, will create a market potential of more than 2,400 tons per year for aluminum complex grease in India.

This is quite a big volume and could bring good value…to your companies, Toth told conference attendees.

Vijay Deshmukh, general manager of research and development at Mumbai-based Standard Greases & Specialities Pvt. Ltd., said the properties of aluminum complex grease are better than lithium, are comparable with lithium complex and that these greases can also be used as food grade lubricants, unlike lithium or lithium complex greases. However, aluminum complex grease has not made significant inroads in the Indian market and hence its share is very low compared with lithium or lithium complex, he noted.

In general, aluminum complex grease costs more than lithium but its cost is comparable or slightly less than lithium complex, Deshmukh said, adding that the cost of key components is one of the factors that prohibits its wide use in the industry.

There is not much growth in aluminum complex greases in India but in case the price of lithium hydroxide increases, aluminum complex greases can replace lithium complex greases in some of the applications and their share may increase, Deshmukh told LubesnGreases. Lithium hydroxide is a key raw material for making greases thickened with lithium-based soaps.

Complex Decision

Despite aluminum complex generally costing more than lithium thickeners, Toth attempted to show the benefits of aluminum complex grease to meet market demand and mitigate lithium supply shortages. He shared the results of two Mol-Lub tests to develop a new aluminum complex thickener for a naphthenic industrial-grade grease and a polyalphaolefin food-grade grease.

For the industrial-grade thickener, the company produced different grease samples with Group I and naphthenic oils using the same procedure and identical molar ratios of ingredients. It found that the carrier oil had an effect on the quality and consistency of the grease. The test also showed that using a naphthenic carrier oil may reduce the thickener treat rate to reach same consistency of final grease. The company observed better fluidity of the thickener and started using naphthenic base oil at very low viscosity.

With a low-viscosity naphthenic carrier oil, even cold flow properties can be improved for better pumpability and processability of the thickener during plant-scale production, Toth said. He noted that applying low-viscosity naphthenic carrier oils resulted in loss of thickening power and treat rate benefits, but significantly improved the thickeners pour point and therefore its pumpability. Thus, they provide a good balance for those grease manufacturing processes that do not use pre-heating.

Our new thickener can be handled more easily during production and its thickening effect is similar or slightly better, he noted.

To make the food-grade grease, Mol-Lub used a PAO base oil. PAOs are said to be non-toxic, non-irritating to humans and hence offer advantages over conventional mineral oils and some natural esters.However, it is a challenge to formulate greases based on PAO oils because of their composition, Toth said. To overcome this, grease manufacturers can choose to increase soap content or align soap structure by carefully selecting proper acid ratios in their formula, he added.

The company produced greases based on the same synthetic PAO as the carrier oil, and the same batch of thickener. The test showed that a low-viscosity and biodegradable PAO can be tailored to specific applications.

Toth concluded that high-quality aluminum complex greases have a place in selected applications, and a low-temperature fluidity aluminum complex grease thickener could be formulated by the careful selection of the naphthenic base oils. He also said the new PAO-based formula is expected to meet future aluminum complex grease manufacturing and application biodegradability regulations.

Meanwhile with PAO, the thickener could help solve the manufacturers dilemma of meeting biodegradability regulations. The use of aluminum complex grease can certainly offer a good alternative in selected areas and also provide a buffer to Indian manufactures from the shock of lithium supply shortage.

Despite its performance virtues, it will likely be market demand, cost and lithium supply conditions that will dictate whether aluminum complex will take hold in India.