MFAs as alternative soap thickeners for lubricating greases
Jan 31, 2022
Ingevity Senior Innovation Chemist Devin Granger and Innovation Manager Shadaab Maghrabi co-published a technical paper, “Modified fatty acids (MFAs) as alternative soap thickeners for lubricating greases” in the recent National Lubricating Grease Institute (NLGI) publication.
This paper uncovers how the pandemic’s impact on supply chains sparked R&D efforts of exploring effective alternatives to traditional grease thickeners to alleviate the dependence on imports and reduce the possibility of production disruptions. Specifically, port closures in India have the potential to disrupt the 12-hydroxystearic acid (12-HSA) supply chain due to the vast majority of the supply used for grease thickeners being produced in India. The introduction of effective alternatives to 12-HSA for use as grease thickeners can help to alleviate the dependence on imports and reduce the possibility of production disruptions caused by supply chain breakdowns.
Initial experimental results indicate that MFAs not derived from castor oil can be used to form thickeners that are shear stable. The developmental MFAs are obtained as reacted products with unreacted fatty acids and can be used without further processing or purification, and subsequently blended for use as grease thickeners. Lithium soaps of the developmental MFA mixtures produce greases with similar texture to referenced lithium 12-HSA greases formulated with the same base oil. Although a slightly higher thickener percentage may be required in the developmental MFA formulations to obtain the same consistency as the referenced grease, these greases exhibit similar shear stability as measured by prolonged working of 10,000 and 100,000 strokes in a mechanical grease worker.
The thickener efficiency of MFA greases are nearly identical to a reference lithium complex formulation (12-HSA and azelaic acid complex lithium soap), with an NLGI grade 4 being achieved at comparable concentrations in different base oils. Worked penetration measurements of developmental MFA greases are comparable to referenced lithium complex formulations. These MFA greases were evaluated for rheological characteristics, oil bleed and dropping point, then compared to standard lithium 12-HSA and lithium complex formulations produced in-house using the same base oil.
Read the paper in its entirety here.