Calcium sulphonate complex greases are advanced non-soap thickened greases that utilise overbased calcium sulphonates as the primary thickening agent.
1. Base Chemistry and Thickener System
This system is created by neutralising calcium sulphonate detergents, followed by a proprietary process that transforms the detergent into a highly structured gel network. The result is a highly stable grease with exceptional lubricating properties, making it well-suited for various industrial applications.
Traditional lithium greases have dropping points around 190 °C, while lithium complex greases extend this to approximately 260 °C. Calcium sulphonate complex greases (CaSuX) can exceed 315 °C, benefiting from calcium carbonate’s presence, which enhances their thermal stability. This dropping point temperature makes them particularly effective in extreme environments. However, the dropping point alone does not dictate a grease’s maximum working temperature. It only signifies the temperature at which the thickener structure breaks down, causing the grease to liquefy. In real-world applications, a grease can fail due to oxidation, base oil evaporation, and mechanical degradation before reaching this point. Several factors influence a grease’s actual operating temperature limit:
Oxidation Stability – High temperatures can cause grease oxidation, leading to thickening, varnish formation, and deposit build-up, reducing lubrication efficiency and increasing component wear. A high-performance grease must exhibit strong oxidation resistance to ensure longevity.
Base Oil Volatility – The base oil is responsible for lubrication, but at elevated temperatures, it can evaporate or degrade, leading to a dry ineffective grease and inadequate lubrication. The choice of base oil type (mineral vs. synthetic) and viscosity significantly affects a grease’s lubrication stability.
Shear Stability & Consistency – Mechanical stress can break down the thickener structure, causing the grease to soften, migrate, or leak from critical components. A well-formulated grease with good mechanical stability maintains consistency under heavy loads and shear forces, ensuring reliable protection.
Thickener Stability – Some thickeners degrade thermally before reaching their dropping point. While certain greases may start breaking down at lower temperatures, calcium sulphonate greases retain their structural integrity for longer, making them ideal for extreme operating conditions.
Although dropping point is a useful indicator of a grease’s heat resistance, a well-balanced CaSuX grease offers superior oxidation resistance, mechanical stability, and base oil retention. These properties make CaSuX greases highly effective in steel mills and heavy machinery, where sustained heat, mechanical stress, and contamination resistance are crucial for reliable operation.
