Krytox XHT-S and XHT-SX greases are special high temperature greases with low oil evaporation that provide long bearing life and are compatible with most elastomers and plastics. These greases provide excellent lubrication over a broad temperature range, but are designed to work best at temperatures over 200 °C (400 °F). Krytox XHT series greases are nonflammable, oxygen compatible, chemically inert, and provide extended lubrication intervals and longer equipment life.
The Krytox XHT-S series greases are an extension of the Krytox GPL 240 series and Krytox GPL 20X series, but are designed to give higher performance in the 204–302 °C (400–575 °F) range. Krytox XHT-S series greases should be used below 320 °C (608 °F), where the polytetrafluoroethylene (PTFE) thickener could begin to melt. The base oil is an extremely viscous oil that provides good viscosity and lower evaporation at high temperatures. Krytox XHT-S series greases contain no additives, so they are used when a potential for interaction between process chemicals and grease additives exists. Krytox grease is made to a standard NLGI grade 2. PTFE is the standard thickener.