SINGAPORE – Production volumes of high performance lithium complex and polyurea grease are growing to meet market needs, an industry insider said at a conference here.
There is increased production of higher performing and more expensive greases. The main drivers influencing the movement from lithium-based greases are lithium hydroxide supply and higher performance market needs, said Andrew Black, general manager technology and manufacturing of Harrison Manufacturing, an Australian toll lubricant and grease blending company.
Some parameters of high-performance greases include longer re-greasing intervals, performance in more demanding operation conditions and suitability for remote delivery or centralized automated grease delivery systems. [Users should] consider total lubrication costs rather than just product costs. These may have higher initial cost but lower total maintenance cost, he added.
Commenting on the decline in the price of lithium by 6.8 percent since the beginning of 2019, lithium hydroxide prices could have a short term impact on lithium grease demand, Black said.
From 2008 to 2018, lithium complex grease production grew by a compound annual rate of 2.4 percent, while simple lithium greases declined by a compound annual rate of 1.7 percent, according to the National Lubricating Grease Institutes annual survey of global grease production. Performance, not initial price, is most likely driving the change, he added.
Other non-lithium grease production expected to grow over the same period include calcium sulfonate grease (13 percent CAGR) and polyurea grease (2.2 percent CAGR). The Asia-Pacific region showed declines in lithium grease production and growth in lithium complex grease and calcium sulfonate grease. India was an exception, with lithium grease production growing recently, according to Black.
Between 2012 and 2018, production of simple lithium-based – lithium 12-hydroxystearate – grease dropped by 57,345 tons, lithium complex grease increased by 35,407 tons and polyurea grease increased by 13,214 tons, according to the survey.
Industry applications for lithium complex grease include the wind turbine, steel mill and automotive industries. Wind turbine grease must be able to function under harsh environmental and physical conditions, in remote locations and also work in situations with extreme relubrication heights, particularly for applications in offshore wind turbines that have tall wind turbine towers.
He cited examples of such greases. Gareth Fish of Lubrizol Corp. shared earlier this year that the company has developed fully synthetic lithium complex greases that passed all the basic industry specific requirements for pitch and yaw bearings and, potentially, main bearings. One formulation used low viscosity polyalphaolefin, and the other used an alkylated naphthalene base oil.
In steel mills, ExxonMobil in China replaced lithium grease with lithium complex grease, reducing bearing failures and consumption, resulting in a 60 percent reduction in consumption or a savings of U.S. $61,000 per year.
In the automotive industry, use of polyurea grease is growing, especially in Asia. There has been a push toward sealed-for-life bearings. Polyurea greases are preferred in this application and other automotive applications such as [constant-velocity] joints, he told attendees at the Asian Industrial Lubricants Conference here, jointly organized by ICIS and the European Lubricating Grease Institute. CV joints connect the drive shafts to the transmission and automotive wheels to enable the transfer of torque at a constant speed.
Polyurea greases have inherent oxidation stability, thermal stability, excellent water resistance and low oil bleed characteristics. With three to five times the life expectancy, they will displace lithium, and lithium complex, particularly at the [original equipment manufacturer] level, he added.
The use of polyurea is expected to grow, particularly in China, which has seen rapid growth in the automotive sector, Black said.
From 2012 to 2018, Chinas lithium grease production dropped 86,028 tons and lithium complex grease production increased by 8,050 tons. China accounts for about one-third of global grease production.
NLGI is examining test methods and the development of new grease specifications that would be in addition to the current GC-LB specification. Many OEMs think that current performance standard is inadequate, and NLGI is examining an improved general multi-purpose grease specification and additional specifications, with performance increases in select areas like water resistance, salt water corrosion-resistance, high load-carrying capacity and longer life, he said.
Tests need to represent true long term bearing life and be relevant to current bearing configurations,” Black said. Examples of problematic tests include high temperature grease leakage, fretting wear, elastomer compatibility and low temperature torque.
Specifications are changing and will require higher performing greases, he said.