Specialty grease thickeners — bentonite clay, PTFE, calcium sulfonate, polyurea — each serve distinct applications based on temperature range, shear stability, water resistance, and regulatory requirements. For formulators choosing between bentonite clay and PTFE-thickened bases, understanding the practical performance differences is essential.
Bentonite Clay Greases
Bentonite clay (montmorillonite) greases are non-melting — they don’t have a drop point in the conventional sense because the clay structure remains solid well above 300°C. This makes clay-thickened greases uniquely suited to high-temperature applications where lithium complex or polyurea greases would melt and run out.
Key characteristics of clay-thickened greases:
- No drop point — structure is thermally stable; no melting failure mode
- Good water resistance — montmorillonite clay provides water-washout resistance
- Excellent high-temperature performance — suitable for kiln car bearings, furnace equipment, glass industry applications above 250°C
- Compatibility limitations — generally incompatible with other grease types; dedicated equipment required
Desilube’s Desiclay G3 is an organoclay rheology modifier specifically formulated for grease applications, providing efficient thickening in mineral and synthetic base oils. Desiclay D3 is engineered for drilling fluid rheology control.
PTFE-Thickened Greases
PTFE-thickened greases offer extremely low friction coefficients and good chemical resistance, but face growing regulatory concerns as PFAS compounds. The EU universal PFAS restriction and EPA reporting requirements are creating compliance uncertainty for PTFE-thickened formulations in some markets.
Additive Package Compatibility
Both clay and PTFE-thickened bases are compatible with Desilube’s EP/AW additive grades. Desilube 88 and 98F have been specifically validated in clay-thickened grease systems, providing NSF HX1-certified extreme pressure performance in high-temperature food processing equipment greases where clay thickeners are preferred for their thermal stability.
Contact Desilube Inc. for formulation guidance: desilubeinc.com/contact