The evolution of industrial greases has been driven by the need for enhanced thermal stability, extreme pressure resistance, and water washout resilience. Over time, the industry has transitioned from sodium and calcium greases to lithium-based greases, which offered improved high-temperature resistance and mechanical stability. However, with the increasing demand for heavy-duty lubricants that perform in extreme environments, calcium sulphonate greases are emerging as the new industry standard. This transition reflects a broader trend in lubrication science—moving towards high-performance greases that require fewer additives while delivering superior thermal and oxidative stability, extended lubrication intervals, and excellent resistance to water and corrosive washouts.
The Evolution of Lithium and Calcium Sulphonate Greases: From Early Developments to Next-Generation Performance
1. A Brief History of Industrial Greases
Lubrication technology has significantly evolved since the 20th century:
• Sodium Greases: First-generation industrial greases that offered high-temperature stability but lacked water washout resistance, limiting their application.
• Calcium Greases: Developed to address water washout resistance but had a lower thermal breakdown threshold (~100 °C), making them unsuitable for high-heat applications.
• Lithium Greases: Introduced as an improved alternative, lithium greases combined moderate water resistance, anti-wear properties, and a high dropping point of up to 190 °C, making them a dominant lubrication choice in multiple industries.
• The Rise of Calcium Sulphonate Greases: Research in the 1950s and 1960s, particularly by Chevron and Lubrizol, led to the development of highly overbased calcium sulphonate complex (CaSuX) greases. These formulations eliminated the need for additional extreme pressure (EP) and anti-wear (AW) additives, making them ideal for high-temperature, heavy-duty, and corrosive environments.
2.The Role of Lithium and Calcium Sulphonate Greases in Modern Lubrication
Lithium greases have long been a benchmark in multipurpose lubrication, offering a well-established balance of performance and affordability. However, for applications requiring enhanced high-temperature and high-load capabilities, calcium sulphonate greases provide an alternative with built-in oxidation resistance, superior load-bearing capacity, and high-temperature stability, reducing reliance on shear-prone EP and AW additives in extreme conditions.
Key benefits of calcium sulphonate greases, particularly in demanding environments, include:
• Superior high-temperature resistance (operating at higher temperatures without degradation).
• Enhanced corrosion and water washout resistance, making them suitable for marine, food processing, and extreme pressure applications.
• Inherent extreme pressure and antiwear properties without the need for additional molybdenum disulphide or zinc-based additives.
• Enhanced mechanical stability, ensuring no shear breakdown even under heavy loads.
• Resistance to hot steam, disinfectants, and cleaning agents.
• Improved adhesion to metal surfaces.
3. The Science Behind Calcium Sulphonate Greases
Unlike conventional soap-thickened greases, calcium sulphonate greases rely on a controlled gelling process, which produces a stable, structured gel with intrinsic extreme pressure resistance, excellent sealing properties, and water washout resilience.
This technology evolved from early overbased calcium sulphonate detergents used in the 1940s, which were initially developed for crankcase oils. Later innovations in the 1950s and 1960s led to the emergence of highly overbased calcium sulphonates, which provided superior corrosion and antiwear protection. By the 1970s, research into controlled conversion processes allowed for the commercialisation of CaSuX greases, setting the stage for their increasing adoption in industrial applications.
One of the key advantages of calcium sulphonate greases is their unique thickening system. Calcium sulphonate greases possess excellent shear stability and a high dropping point, making them suitable for extreme applications. The conversion of amorphous calcium sulphonate into a structured calcite network provides superior mechanical stability, preventing softening or grease breakdown under high loads and stress.
Moreover, the absence of zinc- and phosphorus-based EP antiwear additives in calcium sulphonate greases makes them particularly attractive for industries such as food processing and marine, where contamination risks are critical.
On the other side the EP properties are retained at elevated temperatures making it a great choice for steel and mining. The great resistance to water and cleaning agent washout is desirable for both.
4. The Future of Industrial Greases
While lithium-based greases remain a reliable and proven choice in many applications, the growing demand for more durable, environmentally sustainable, and multipurpose lubricants has led to increased adoption of calcium sulphonate greases, offering enhanced performance in extreme conditions.
• Superior thermal and oxidative stability for high-temperature applications.
• Exceptional resistance to corrosion, water washout including salt water, and contaminants.
• Extended lubrication intervals, reducing maintenance frequency and downtime.
• Compatibility with lithium-based greases
As industries face increasingly extreme operational demands, calcium sulphonate greases are gaining traction in applications requiring mechanical stability, high load-carrying capacity, and resistance to extreme environments. The lubrication industry’s focus on sustainability and optimising additive formulations is driving further advancements in grease technology, expanding the range of solutions available to meet diverse industrial needs.
