The National Lubricating Grease Institute, a not-for-profit trade organization, contributes to the growth of the grease industry by supporting the development of better lubricating greases and the improvement of grease lubrication engineering. Its activities include technical meetings, grease product certifications, educational courses, publications and professional certifications. The European Lubricating Grease Institute has a similar role and activities centered in Europe. Many members of each organization are grease manufactures and marketers, raw material and equipment suppliers, and end users.
Working groups are one of the ways that both organizations promote understanding of technologies and facilitate exchange of information about grease. Each working group consists of professionals from member companies who collaborate on projects that interest the industry. The groups meet at NLGI and/or ELGI meetings to plan and carry out projects at member laboratories. These projects are at the leading edge of developments of broad commercial interest.
“The working groups provide companies with a ‘seat at the table’ regarding pertinent industry issues,” said Crystal O’Halloran, NLGI executive director. “These meetings connect industry professionals from across the globe who are working toward a common goal to advance the grease industry.”
Lubricating greases go (and stay) where liquid lubricants cannot. Metalworking fluids, engine oils and hydraulic fluids are sprayed, splashed or circulated through engines, pumps and nozzles. Lubricating greases are semisolid materials that are loaded into bearings and other mechanisms where they provide long-term service.
A grease formulation is basically a liquid lube plus a thickening agent. The thickener adjusts the consistency, stringiness, adhesion, cohesion and other unique performance properties. Formulations of current grease products are the results of many innovations over the course of almost four millennia. Estimates of the value of the 2021 global grease market range from $ 4.2 billion to $ 5.45 billion.
Food-Grade Lubricants
Food-grade lubricants are niche products formulated and manufactured specifically for applications with particularly rigorous safety requirements. According to the NLGI Grease Glossary, the term food-grade is used casually to refer to lubricants certified by NSF International for use primarily for processing food and beverages, personal care products and pharmaceuticals (e.g., assembly lines for mixing, cooking, preparing and packaging). Thus, FGLs are critical components of the food chain.
Larry Ludwig of Schaeffer Oil chairs the Food-grade Lubricants Working Group for NLGI. Andreas Adam of FRAGOL GmBH, Sofia Oberg of 2Probity Registration AB and Perry Peters of Matrix Specialty Lubricants BV lead the FGLWG on behalf of ELGI.
The FGLWG serves as a platform for roundtable discussions about FGLs as well as standards and regulations for their use in different countries. Suppliers must understand the various classifications, compositions and best practices for manufacturing FGLs. They benefit by appreciating the value of FGLs to end users and the concerns of end users regarding safety. Another benefit is the opportunity to learn about trends such as shifts in consumption patterns.
According to Ludwig, the FGLWG educates and updates participants and the grease industry on issues and regulations related to FGLs. This includes developing a shared vocabulary for communicating with end users about food safety.
A position paper on FGLs includes definitions of technical terms and answers to frequently asked questions about the use of lubricants in food processing and related industries. It is available on the ELGI website.
The paper clarifies that the casual terminology “food-grade lubricant” is only acceptable in reference to H1 lubricants that are registered by NSF International or the International Numbering System for Food Additives.
In formal or technically correct terminology, H1-registered lubricants are those that meet requirements for incidental contact with food or other products and contain only components (termed HX-1) defined by the United States Food and Drug Administration. Incidental contact means that an H1 lubricant is not expected to but may occasionally come into contact with food under normal use conditions. The FDA defines the permitted ingredients for greases and other lubricants for use in food processing and handling applications where incidental contact may occur (i.e., H1 lubes).
H2 and H3 lubes do not meet registration requirements regarding composition and are not suitable for use in applications where incidental contact with food or other products may occur.
The FGLWG is helping the grease industry address a relatively new challenge. End users increasingly focus on risk assessments of their manufacturing processes and sources of contamination in their supply chains. The BfR (Bundesinstitut fur Riskikobewertung or Federal Institute for Risk Assessment) has developed a test to help end users detect hydrocarbon contaminants in foodstuffs. The BfR test consists of methods to extract, pre-separate and quantitatively determine low levels of hydrocarbons in packaging materials and dry foodstuffs.
The BfR test uses gas chromatography with flame-ionization detection to measure low concentrations (parts per million) of two groups of chemicals. One group consists of mineral oil saturated hydrocarbons, polyolefin oligomeric saturated hydrocarbons and polyalphaolefins. The second group is mineral oil aromatic hydrocarbons.
Each group includes multiple compounds with different chemical and toxicological properties. The current BfR methodology does not provide data about individual compounds. Nevertheless, end users are applying the results of the BfR test to identify sources of hydrocarbon contaminants in supply chains.
Suppliers of lubricants and their components are receiving customer requests to guarantee that their products do not contain chemicals that could be detected by the BfR test and regarded as harmful contaminants. How realistic is this request?
According to a report by Mobil, potential sources of MOSHs and MOAHs include equipment used in harvesting, the environment and feedstocks as well as lubricants for food preparation and packaging equipment. Mobil’s report summarizes BfR test results for a variety of base oils and fully formulated lubricants. MOSHs were detected in all nine base oils (including three HX-1 oils used in H1 formulations), in five of six lubricants (including an H1 gear oil), and both greases tested (including an H1 aluminum complex grease).
Test results for the presence of MOSH in various base oils and lubricants
Mobil reported that the BfR test detected MOSHs in all samples of Group I-III mineral oils, Group IV-V synthetic base oils and lubricants except a synthetic gear oil based on polyalkylene glycol. MOSHs (and sometimes MOAHs) were detected in H1 lubricants and HX-1 base oils as well as non-food-grade products. The report recommended the use of H1 registered lubricants to manage risk associated with incidental contact between lubricants and food, beverages and other products,
ELGI issued a position paper on this topic that supports the safety of H1-registered mineral oil-based lubricants and greases in the mechanized production of food, animal feed and pharmaceuticals.
The FGLWG addresses issues that are global in nature, Ludwig said. One of the next steps is to increase interactions with lubricant end users to provide guidance and keep them informed on the usage of food-grade greases. The development of additional testing protocols is an ongoing goal.
Biobased Lubricants
Ludwig and George Dodos of Eldon’s SA are currently co-chairs of the Biobased Grease Working Group. “The goals and aims of the joint NLGI/ELGI BGWG are similar to those of the FGLWG: i.e., to provide education and updates on issues, regulations and concerns relating to the use of biobased greases and lubricants,” Ludwig said.
A steering committee has been set up to develop a position paper to define and improve understanding of the definitions, regulations and uses of biobased and biodegradable lubricants.
Progress is being made on defining, understanding, and developing test methods to evaluate the cold flow properties, oxidation stability, high-temperature performance and hydrolytic stability of biobased greases. ASTM D8206-18 Standard Test Method for Oxidation Stability of Lubricating Greases Rapid Small-Scale Oxidation Test has been found to be a viable test method. Other methods for measuring the cold flow properties and hydrolytic stability of biobased greases are currently being evaluated, and round robin testing is being set up.
Grease Specifications
NLGI licenses more than 270 automotive greases that meet specifications based on ASTM standards. These products are identified by NLGI Certification Marks. After a discussion at an ASTM D02 B04 Automotive Grease meeting in 2012 about the need to upgrade the NLGI GC-LB Wheel Bearing and Chassis Grease specification to better meet the needs of the automotive industry, the GSWG was organized under the leadership of Gareth Fish of Lubrizol Corp.
ASTM D4950 Automotive Greases Test Status
The GSWG learned that more than 90% of automotive grease applications were sealed for life. NLGI tasked the GSWG with the development of a new specification with higher performance and broader utility. The GSWG developed new NLGI specifications for high-performance multiuse (known as the HPM spec) grease and four sub-categories with enhanced water resistance, load carrying capacity, saltwater corrosion resistance and low-temperature performance.
According to Fish, the original GSWG was disbanded, and a new GSWG was organized to develop specifications for HPM greases with enhanced long-life and high-temperature performance; Chuck Coe of Grease Technology Solutions is the new chair.
Railway Lubricants
Matt Smeeth of PCS Instruments chairs the ELGI Railway Lubricants Working Group. The RLWG supports the Railway Safety and Standards Board, which is updating European standard EN 15427 for lubricating wheels of railroad cars. The standard specifies intermediate coefficient of friction (0.3-0.4) modifiers for the crown of the rail and the tread of the wheel to prevent braking issues, and low COF (0.1-0.2) greases for the shoulder of the rail and the flange of the wheel to suppress unpleasant squeaking and wear when a train moves on curved track.
The goal of the RLWG is to introduce relevant wear and friction tests for the new standard. Marc Ingram of Ingram Tribology used a rig based on a Mini Traction Machine to establish a performance baseline for lubricants. An independently driven ball and disc are used to measure traction as the contact is gradually changed from rolling to sliding at 1 meter per second entrainment (3.6 km/h train speed).
The RLWG collaborated on round robin testing of greases to evaluate the new test method. Graphs of traction versus percent sliding differentiated clearly between high and low COF products suitable for different railway applications. The new method is being included in the updates to EN 15427.
Grease Particle Evaluation
The Grease Particle Working Group is chaired by Joe Kaperick of Afton Chemical and is investigating the use of the Hegman gauge in grease testing. The Hegman gauge is a stainless steel block with a trough machined on the top. A fluid or semisolid sample is pushed into the trough, which gradually increases in depth. Hard particles form “tracks” where the depth corresponds to their size. Sixteen corporate laboratories participated in round robin testing of greases. It was feasible to use the Hegman gauge for greases, but the reproducibility was limited.
The GPWG surveyed 55 grease manufacturers, OEMs and others. Most agreed about the need for a new method to evaluate hard particles in grease, especially the size and number of particles and the risk for damage in applications. The GPWG is writing a white paper to review available test methods for particles in greases while improving the technique for using the Hegman gauge, which is inexpensive, simple and quick.
Mary Moon, Ph.D., has experience formulating, testing and manufacturing lubricating oils and greases and polymers. She has served as Chair of the Philadelphia Section of STLE and Technical Editor of The NLGI Spokesman and received the Clarence E. Earle Memorial Award (2018) and the Golden Grease Gun Award (2022) from NLGI. She is currently working as a professional writer and editor. Contact her at mmmoon@ix.netcom.com