Krytox® XHT-S and XHT-SX

PRODUCT INFORMATION
DuPont™ Krytox® XHT-S grease and DuPont™ Krytox®
XHT-SX grease 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-S and SX greases are nonflammable, 
oxygen-compatible, and chemically inert, and they provide 
extended lubrication intervals and longer equipment life.
Typical Properties of Krytox® XHT-S Series PFPE Grease*
XHT-S XHT-SX 
Estimated Useful Range
°C –20/300 –10/300
°F –4/572 14/572
Base Oil Viscosity, cSt
20 °C (68 °F) 1,712 2,610
40 °C (104 °F) 500 738
100 °C (212 °F) 47 65
Oil Viscosity Index 149 158
Oil Pour Point
°C –25 –15
°F –13 5
Vapor Pressure
20 °C (68 °F) (Knudsen) ≤1 x 10–9 ≤3 x 10–14
100 °C (212 °F) (Knudsen) ≤8 x 10–7 ≤1 x 10–9
200 °C (392 °F) (Knudsen) ≤1 x 10–4 ≤2 x 10–6
Maximum Volatility in 22 hr, %
204 °C (400 °F) <1 <0.75
Appearance White, creamy White, creamy
consistency consistency
Specific Gravity at 0 °C (32 °F) 1.99 1.99
Food Contact Approval None NSF H-1
The Krytox® XHT-S and XHT-SX grease series is an extension of 
the Krytox® GPL 240 series and the Krytox® GPL 20X series, 
but the Krytox® XHT-S and XHT-SX greases are designed to give 
higher performance in the 204–302 °C (400–575 °F) ranges.
The Krytox® XHT-S and XHT-SX greases should be used below 
320 °C (608 °F), where the 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 and XHT-SX greases contain no additives, so they 
are used where 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.
Typical Applications 
Applications for these lubricants are generally of a critical nature, 
such as where temperatures reach extremes that conventional 
lubricants cannot handle. Krytox® XHT-S and XHT-SX greases 
are expected to be durable in highly aggressive environments. 
Where failure of components is not an option whether because 
of durability, warranty, safety, loss of productivity or down 
time, Krytox® lubricants are the ideal choice in a wide range of 
industries and applications.
Typical applications for Krytox® XHT-S and XHT-SX include: 
•     paint plant conveyor bearings
•     corrugator and paper machine bearings
•     aluminum can manufacturing bearings
•     welding machines
•     high temperature fans
•     textile equipment
•     tenter frames
•     high temperature ovens
•     conveyor systems in glass and aluminum plants
•     textile calender roll bearings
•     brick kiln car bearings
•     valve lubrication
•     ventilation fan bearing grease
•     rod mills
•     valves
* This table gives typical properties (not specifications) based on historical production 
performance. DuPont does not make any express or implied warranty that these 
products will continue to have these typical properties.
†
 NLGI = National Lubricating Grease InstituteDuPonT
™ KryToX
® XHT-S AnD XHT-SX GrEASES
DuPont™ Krytox® PFPE oils and Greases
Perfluoropolyether (PFPE) oils are clear, colorless, fluorinated 
synthetic oils. These oils are nonreactive, nonflammable, safe in 
oxygen service and are long lasting. Krytox® oil is a PFPE — also 
called perfluoroalkylether (PFAE) or perfluoropolyalkylether 
(PFPAE) with the following chemical structure:
F-(CF-CF2
-O)
n
-CF2
CF3
 | where n = 10 to 60
 CF3
The polymer chain is completely saturated and contains only 
carbon, oxygen, and fluorine. On a weight basis, a typical Krytox®
oil contains 21.6% carbon, 9.4% oxygen, and 69.0% fluorine. 
Compatibility with Metals
Because of their low surface tensions, Krytox® lubricants easily 
wet metallic surfaces. Krytox® lubricants are chemically inert 
and, therefore, have no adverse effect on metals when the 
temperature is below 288 °C (550 °F). Above 288 °C (550 °F), 
many alloy steels, stainless steels, and other metals such as 
aluminum alloy, titanium alloy, nickel alloy, and cobalt alloy can be 
used with Krytox® lubricants.