Performance Lubricants

For Clean Room Applications

Product Information
Understanding Lubricants in Clean Rooms
Grease is a semisolid material that uses a thickener tohold the oil in place. The base oil is the largest componentof any grease, but the grease’s thickener and additives
can also have a large impact on contamination of aclean room. Commonly used thickeners are metallic soapsof lithium and aluminum, solids like clay and silica, or solid
polymers such as polytetrafluoroethylene (PTFE) andpolyurea. Greases reduce the volume of lubricant neededfrom what would be typical in an oil system.
Lubricants for use in clean rooms require base oils thathave been specially distilled to remove the more volatile,lighter molecules that might evaporate easily. In addition,
the use of special thickeners that do not contain metals,
reactive compounds, or large particles is also necessary
to meet some clean room standards.
Hydrocarbon, polyalphaolefins (PAO), synthetic esters,
silicones, polyphenyl ethers (PPE), and perfluoro­
polyethers (PFPE) are a few common base oils used in
the clean room environment. The least expensive choice
is hydrocarbon- or PAO-based lubricants. These commonbase oils have good wear properties and can accept
common additives; but, often, they don’t handle hightemperatures and minimal outgassing requirements. In
addition, the additives necessary to keep them stable arereactive and can cause problems if they get on criticalcomponents.
Synthetic ester base oils have higher thermal stability, but
are more reactive and can’t be used with some elastomer
seals and plastic materials. Silicone-based lubricants

have a broader useful temperature range and are safewith plastics and seals, but are more compressible anddon’t do as well lubricating metal bearings. In addition,
they have been known to creep into other areas, causing
contamination issues.
At the high end of the performance scale are thePPE lubricants and PFPE lubricants, such as Krytox™
lubricants. These oils have higher molecular weight
and low vapor pressure. The PPEs have good radiation
resistance, but typically are not good lower temperaturelubricants. PFPE lubricants offer wide temperature range
capability, chemical inertness, and compatibility withalmost all seals and plastic materials.
Factors That Influence Lubricant Selection
The potential for wear can be reduced in components
by using components that roll, rather than slide, and by
the proper selection of lubricants. Some lubricants havethe potential to evaporate and create chemical vapors or
decompose and form particles that can become airborne.
Cost is a factor in the selection of a lubricant. Consider­ation of its life cycle can show that the clean-up costs fora lubricant that has to be re-applied frequently can makeit cost significantly more than a higher performing productthat does not require repeated re-lubrication. The controls
needed—to capture excess lubricant, chemical vapors
given off, and particles generated from decomposition of
the lube—and the risk of wear and failure of the equip­
ment, because of lubrication issues—all add risk and cost.

Krytox™

Performance Lubricants

Microbial control presents an additional challenge inpharmaceutical, medical, and food processing clean
room environments. Commonly, antiseptic cleaning,as well as thermal and radiation methods, are used
to kill and remove microorganisms. If the actual
lubricated component is directly subjected to any ofthese operations, it must be able to withstand thestress. Repeated steam sterilization in an autoclave at
121–132 °C (250–270 °F) can take many lubricants
past the point that their additives and base oils canhandle, leading to shortened life. Overzealous use of liquid
sanitizers could flood a bearing with cleaner, causing
corrosion or chemical decomposition of the base oil,thickener, or additives.

Recommended Grease Types

Lubricant selection ultimately becomes a matter ofselection of the proper chemistry and physical properties
that will not create contaminants from volatilization,
chemical decomposition, or excess wear. While solidlubricants, such as molybdenum disulfide, PTFE coatings,
or graphite, can reduce friction and reduce wear, they
typically have short lives in most applications and areusually not used in rolling element bearings. While oils canbe used as lubricants, they are typically used in systems
that have oil reservoirs—where the oil is used both forlubrication and cooling.
Vapor pressure is another consideration to include whenselecting a lubricant. The equipment must be properly
lubricated with the correct viscosity base oil or it could failrapidly. Many extreme vacuum greases use high viscosity
base oils to lower vapor pressure. They won’t outgas, but
are so viscous that the balls of a bearing will skid and cause
high wear—resulting in rapid failure and creating particles.

Krytox™ greases can meet many of the critical needs inclean room and robotic applications (see Table 1).
Key Considerations in Clean Room Applications
In addition to selecting high performance lubricants,
the choice of bearings and seals used in the clean
room equipment must also be carefully considered.
Specially cleaned bearings with seals designed toreduce outgassing and particle generation are needed.
Composition of the bearings could include stainless or
ceramic balls, stainless races, and special cages.
External particles and other contaminants compete
against the air filtering system. People entering a clean
room are required to wear special clothing, all materials
entering must meet special cleanliness standards,
and the equipment is designed to generate minimal aircontamination. If the moving equipment in the room is
not lubricated or inadequately lubricated, particles canbe generated inside the room from bearings, slides, seals,
and the lubricants used.
Mechanical operations inside a clean room can range fromvacuum system operations, manufacturing operations,such as molding, and final assembly. Virtually any place
where metal can rub could potentially create micronsized metallic wear particles, if the contact points are notlubricated. For instance, a mold has ejector pins, latch
locks, and other components that slide. If the components
are properly lubricated, the wear of these components
can be minimized, reducing particle generation.

Table 1. Krytox™ Vacuum and Clean Room Greases1
Base Oil Viscosity,cSt at 40 °C (104 °F)

Vapor Pressure,
Torr

ASTM
E5952

Applications

Krytox™ 240 AA

33

1 x 10–4 at 38 °C (100 °F)—

Electronics

Krytox 240 AB76

5 x 10 at 38 °C (100 °F)—

Electronics

Krytox EG 2000

240

8 x 10 at 38 °C (100 °F)

Pass

Electronics

Krytox EG 3000

440

6 x 10 at 38 °C (100 °F)

Pass

Electronics

Product™
™

™

–6–8–9Krytox LVP749<1 x 10at 20 °C (68 °F)

Pass

Sealing, Electronics

Krytox™ XHT-BD

599≤1 x 10–9 at 20 °C (68 °F)

PassHigh temp flow solder ovens

Krytox™ XHT-BDX

738≤3 x 10–14 at 20 °C (68 °F)

PassHigh temp flow solder ovens

Krytox XHT-BDZ

1023≤4 x 10

Pass

High temp flow solder ovens™

™

–13–15at 20 °C (68 °F)

Note: These values are typical properties and not specifications.

1E595 criteria to pass is <1% for Total Mass Loss and <0.1% for Collected Volatile Condensable Material.

2Performance Lubricants

Krytox™

Table 2. Krytox™ Vacuum and Clean Room Oils1Base Oil Viscosity,cSt at 40 °C (104 °F)

Vapor Pressure,
TorrApplications

Krytox™ XHT-500

500≤1 x 10–9 at 20 °C (68 °F)

Electronics

Krytox XHT-750738≤3 x 10at 20 °C (68 °F)

Electronics

Krytox XHT-1000

1023≤4 x 10at 20 °C (68 °F)

Electronics

Product™
™

–14–15

Note: These values are typical properties and not specifications.

1Krytox™ PFPE Lubricants
In addition to the wide temperature range capability,
chemical inertness, and compatibility with most materials,
Krytox™ PFPE lubricants offer selections of new soluble
additives that provide improved lubrication properties.
The higher density of 1.9 g/mL and higher molecularweight make Krytox™ PFPEs less likely to outgas.
Krytox™ PFPE lubricants have one additional
characteristic that makes them an ideal choice forrobotics. The static coefficient of friction is lower thanthe dynamic coefficient; so, they have no stick-slip, which
eliminates jerkiness. This attribute supports the ability to
precisely control and position components.

Krytox™ Lubricants—Ideal for the Clean RoomEnvironment• Exceptionally safe, reliable, and offer longer
lubricant life
• Highly resistant to degradation in the presence of
aggressive chemicals• Perform well in both low and very high temperature
conditions• Protect equipment under high loads and slower speeds,
while enabling components to last longer• Will not burn or support combustion, even in 100%
liquid or gaseous oxygen• Do not damage plastics or elastomers, or cause
corrosion to metals
Krytox™ lubricants are used in aerospace, automotive,
industrial, and semiconductor applications, as well as insolving many other routine lubrication problems.

The information set forth herein is furnished free of charge and based on technical data that Chemours believes to be reliable. It is intended for use by persons having technical skill, at their own discretion and risk.
The handling precaution information contained herein is given with the understanding that those using it will satisfy themselves that their particular conditions of use present no health or safety hazards. Because
conditions of product use are outside our control, Chemours makes no warranties, express or implied, and assumes no liability in connection with any use of this information. As with any material, evaluation of any
compound under end-use conditions prior to specification is essential. Nothing herein is to be taken as a license to operate under or a recommendation to infringe any patents.
Unless agreed to by Seller in a prior written agreement covering such use, in no event shall Buyer use products or resell products for use in the manufacture of any implanted medical device, or for any othertemporary or permanent use in the human body, or in contact with internal body fluids or tissues.

For product information, industry applications, technical assistance, or global distributor contacts, visit krytox.com or within theU.S. and Canada, call 1-844-773-CHEM/2436 or outside of the U.S., call 1-302-773-1000.
© 2024 The Chemours Company FC, LLC. Krytox™ and any associated logos are trademarks or copyrights of The Chemours Company FC, LLC. Chemours™ and the Chemours Logo aretrademarks of The Chemours Company.

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