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PerfluoropolyethersPerfluoropolyethers
Stephen Whitlock
Performance Lubricants
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Synthetic LubricantsSynthetic Lubricants
Synthetic hydrocarbon Silicone
Polyalkylene glycol Silicate
Diester Phosphate ester
Polyolester Polyalkylbenzene
Polyphenylether
Fluorinated Lubricants
Chlorofluorocarbon
Fluorosilicone
Perfluoropolyether
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ChlorofluorocarbonsChlorofluorocarbons
Polychlorotrifluoroethylene (CF2CFCl)n
First synthesized in 1940s for uranium work.Range of products from light oils to waxes.Greases are commonly thickened with silica orPTFE.
May react with aluminum, can cause rusting ofsteel, may damage Buna, silicone rubber, naturalrubber, CTFE polymers, and PVC. Maximum safeoperating temp of 400F. Subject to thermalbreakdown above 580F. Soluble in most organicliquids. Non flammable and oxygen compatible.
Applications in chemical service such as chlorine,
metalworking lubricants, pump oils, etc.
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Fluorosilicone FluidsStrengths: High Viscosity Index
Wide Viscosity Ranges for High
and Low Temperature Applications
Water Repellant
Oxidation-Chemical-Thermal Stable
Low VolatilityGood Plastics Compatibility
Weaknesses: Poor Wear and Load Characteristics(Dimethyl- low, Phenylmethyl- Better, Fluoro- Best)
Highly Compressible
Applications: Specialty greases and fluids
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Perfluorinated Polyethers
Strengths: Highest Stability
Very wide Temperature Range
Very low Volatility
Non Flammable, Non Reactive
Compatibility with Elastomers, Plastics
Excellent Lubricity and Load Carrying
Weaknesses: Fewer additives available
Applications: Oxygen Service
Sealed for Life / Low Maintenance Needs
Vacuum Pump Fluids
Automobile Bearings
Oven Bearings and Chains
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Common Theme for UsesCommon Theme for Uses
High Temperature Applications whennothing else will work
Safe in oxygen
Chemically inert and non reactive Very long life performance in applications
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PFPE Oils & GreasesPFPE Oils & Greases
Used as:
Lubricant
Vacuum pump fluid
Functional fluid
Mold releaseSealant
In:
AerospaceAutomotive
Chemical
Computer
Oxygen system
Paper machinery
Petroleum handling
Power PlantSemiconductor
H-1Food applications
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PerfluoropolyetherStructures
Perfluoropolyether
Structures
Shielded
CF3CF2CF2-[-O-CF-CF2]x-O-CF2CF3
Non-Shielded Types
CF3-[-O-CF-CF2-]Y-[O-CF2-]mO-CF3
CF3-[-O-CF2-CF2-]Z-[-O-CF2]n-O-CF3
CF3CF2CF2-[-O CF2-CF2-CF2-]o-O-CF2CF3
CF3
CF3
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-60 -40 -20 0 20 40 60 80 100 140 160 180 200 240 260 300Temperature C
High Viscosity Range Normal Range
Continuous use
Low Viscosity Range
Petroleum
Diesters
PolyalphaolefinsPolyolesters
Silicones
PFPE-K
PFPE-Z
Comparison of Temperature Limits
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PFPE LubricantsPFPE Lubricants
Chemical Properties
Wont burn
High temperature stable Low evaporation rate
Insoluble
Non-reactive
High density of 1.9 vs standard oils
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PFPE Lubricants: Non-FlammablePFPE Lubricants: Non-Flammable
No flash point
No auto-ignition point
No reaction with
oxygenPFPE
Hydrocarbon
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PFPE Lubricants:
High Temperature Stability
PFPE Lubricants:
High Temperature Stability
Up to 650 F
No chemical breakdown
Breakdown products are volatile
No tars or deposits
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High Temperature StabilityHigh Temperature Stability
In oven at 232C for 40 hours
Hydrocarbon40% loss
PFPE0% weight loss
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PFPE Lubricants: SolubilityPFPE Lubricants: Solubility
Insoluble in:Hydrocarbons
Water
Steam
Chemical solvents
Acids and bases
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PFPE Lubricants: Chemically InertPFPE Lubricants: Chemically Inert
No chemical attack by or to:Boiling sulfuric acid
Fuming nitric acidHydrofluoric/ hydrochloric acid
Strong oxidizers
Water/steam
Molten/aqueous caustic
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Viscosity / Volatility
20C
vis
Approx
MW
Approx volatility
7 960 100% @ 250F
16 1180 30% @ 250F
36 1720 20% @ 250F
80 2275 7% @ 250F180 3150 3% @ 250F
550 4730 2% @ 250F
800 6250 1% @ 250F
1600 8250 < 1% @ 250F2700 11000 0 % @ 250F
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Viscosity-Temperature
Relationship
Viscosity-Temperature
Relationship
0 20 100
cSt10000
1000
100
10
Viscosity
Temperature (o C)
Silicone
PFPEK,YCTFE
PFPED
PFPEZ
-40
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700o F
PFPE Fluorinated OilCompatibility with Metals & Alloys in Air
PFPE Fluorinated Oil
Compatibility with Metals & Alloys in Air
650o F
600o F
550o F
371o C
343o C
316o C
288o C
Ni & Co.Monel
Ni/Co/CrSTEEL
Mg. Al, Cr
VTi (6AL6V2SN)
300 Series & 446 S.S.Bronze, A1
Ti (13V11Cr3A1)Ti (6A14V)
400 Series S.S., Tool &Bearing Steel
Cu
Ti (8 Mn)
Most Metals and Alloys are
Compatible Below 550o F (288o C)
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PFPE Fluorinated OilCompatibility with seals and plastics
PFPE Fluorinated OilCompatibility with seals and plastics
There are no reactions such asswelling or shrinking with plastics andelastomeric materials used in seals
or other components.No reaction with paints or other
components.
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Thermal & Oxidative DegradationProducts of PFPE Oils
Thermal & Oxidative Degradation
Products of PFPE Oils
C3F7[OCF(X)CF2]y OCF2CF3 :x=CF3,F
Inert Atm [02]600-650o F
CF3CF=CF2
+
CF3COF
+COF2
CF3CF=C0F
+
COF2
Secondary Rxs
CF3COOH, HF, CF3H. CO2CF3COFH2O
COF2
SiO2SiF4, CO2
H2O
CO2, HF
SiO2SiF
4
, CO2
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PFPE Oils and GreasesPFPE Oils and Greases
Clear oil is basic PFPE product
Different viscosity grades available Prepared by distillation
Greases made by thickening oils
Typically made with High-Temperature Thickenerssuch as Polytetrafluoroethylene (PTFE)
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PFPE Oils and GreasesPFPE Oils and Greases
Additives Only special soluble ones for oils Grease
Extreme pressureMolybdenum disulfide
Graphite
Anti-rust & high temperature anti-
corrosion Sodium nitrite Disodium Sebacate
Soluble additives from manufacturer of oils
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Typical Lubricants
Wear & Load Carrying Ability
Typical Lubricants
Wear & Load Carrying Ability
Oil
PFPEChlorofluorocarbonFluorosiliconeDiesterPetroleum oil
4-Ball Wear
Scar, mm*
0.360.370.430.610.69
Falex Pin/V-Block
Fail Load, LB.
>4500>4500
110023001300
* 20 kgf / 225o F / 1200 RPM / 60 min / 52100 steel on steel
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Extreme PressureExtreme Pressure
Falex Pin/V Block TestVery-high-pressure capableFalex Pin/V Block TestVery-high-pressure capable
Hydrocarbon on left shows welding,
PFPE on right has no welding
Hydrocarbon on left shows welding,
PFPE on right has no welding
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Typical ASTM D-3336 test results
2000+250C / 482F500 / 47-20 to +300PTFE / PFPE
5000+200C / 392F160 / 18-36 to +204PTFE / PFPE
5500+200C / 392F100 / 12.3-40 to +200PTFE / PFPE
4900+180C / 357F60 / 9-51 to +179PTFE / PFPE
Typical PFPE greases
400+177C / 350F29.3 / 5.6-54 to +177Organo-clay / PAO
500176C / 349F150 / ----- to +200Lithium complex / polyolester
600+150C / 300F-- / 31.8-23 to +177Microgel / hydrocarbon
750+177C / 350F115 / 12.2--Polyurea / hydrocarbon
Approx 3000 ***600
150C / 300F177C / 350F
116 / 12.3-29 to +177**Polyurea / hydrocarbonoil
Life, hoursTesttemperature
Viscosity40C/100CcSt
RecommendedTemp range, C
Competitive grease*(from manufacturers data sheets)
* Major corporate grease manufacturers
** This manufacturer claims the maximum operating temperature is the highest temperature at which the grease could be used with frequent (daily) relubrication.
*** Manufacturer claims this is nearly 10 times the life possible when using conventional lithium greases.
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Bearing Life Test
High Temperature Vacuum
Bearing Life Test
High Temperature Vacuum
0
1000
2000
3000
40005000
6000
7000
8000
900010000
PFPE Fluoro-
Silicone
Mineral o il
product
Silicone CTFE
Hours to Failure
NASA N85-11239, OCT 1984, 3600 RPM, 5 lb Load, 93.3 C, 1X10-6 Torr
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ApplicationsApplications
Steam resistant,long lasting,high pressure
grease
High performance automotivecomponent bearing grease
Inert low vaporpressure oils
Non migratingheat resistantgrease
Nato approved lifesupport systemsealing paste
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Aerospace / AviationAerospace / AviationHigh speed bearings
Synchronous motor bearings in gyroscope
Sealant / caulk for space suitsOxygen breathing systems-vehicle & space suit
Traction motors on lunar rover
Boeing wing flap actuator
O-ring lubricant
Assembly lubricant
Rocket engine assemblies
- Reduction gears- Turbine, pump, gimbal bearings
- Threaded fasteners
Harpoon missile rear main bearing (Max. temp. ->800o F)
De-icing hot air diversion seal lubrication
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Vapor Pressure / OutgassingVapor Pressure / Outgassing
Select grades have been developed for use in applicationssuch as aviation, aerospace and clean rooms where
outgassing is an issue or vacuum applications where vaporpressure is critical.
0.13 / 0.092%6 X 10-11TorrL-220
0.26 / 0.056%4 X 10-10TorrL-150
--8 X 10-13TorrLVP
0.22 / 0.023%8 X 10-8Torr240 AC
--5 X 10-6Torr240 AB
TML / CVCMVapor Pressure
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PFPE Automotive ApplicationsPFPE Automotive Applications
Assembly plant conveyors and chains
- High temperatures & loadsAnti-lock braking system ball screw- Compatible with brake fluids & elastomers
Fan-clutch ball bearing- Extended life, reduced warranty claims
Spark Plug Boot & Weatherstripping-Compatible lubricant
Race car CV joint, clutch, wheel bearing- High speeds, temperature & loads
Alternators, Sintered metal
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Automotive ApplicationsAutomotive Applications
Spark Plug Boots
Alternator Bearings
Clutch Pilot Bearings
Sintered Metal Bushings
Weatherstripping
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PFPE Industrial ApplicationsPFPE Industrial Applications
Bearings
- Corrosive environments- High temperatures
- Hard to lube areas
- Critical parts
Valves- Plug, ball
- Relief
Functional fluid- Sealant
- Hydraulic fluid
- Inert fluid
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The TrueCost
of Lubrication?The TrueCost
of Lubrication?
Price of the LubricantPlus
Cost of MaintenancePlus
Cost of Lost Production
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PFPE Applications: ValvesPFPE Applications: Valves
Valve Moving Parts
Packing- Good lubricity, reduces sticking, reduces emissions
- Low evaporation
- High temperature stability to 600o F
- No chemical breakdown- Insoluble
For:- Oxygen or Chlorine
- Strong acids, bases- Steam, water
- High temperature
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Control Valve LubricantControl Valve Lubricant
PFPE Grease
- Reducesticking
- Reduce
leaking
Operating Conditions
-High temperatures
-Corrosive chemicals
-Hydrocarbons
No Stick Slip with PFPEs
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Considerations in PFPE UseConsiderations in PFPE Use
Bearings free of all hydrocarbon or otherorganic residues
Lower thermal conductivity and thicker filmscould cause bearings and equipment to runslightly hotter
Not for use on aluminum bearing surfaces
Higher density - fill bearings by volume, notweight
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PFPE FuturePFPE Future
Lubrication requirements becoming more
demanding- New technology is pushing traditional design envelopes
- PFPEs have been identified as next generation aviation
lubricants by leading-edge designers
Lubricant purchase cost less important than
lifetime intervals- Reduced down-time and longer re-lube intervals
- Lubricated-for-life applications
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Additional ReferencesAdditional References
Synthetics, Mineral Oils and Biobased Lubricants,
Taylor and Francis Books, 2005, Chapter 8,
Perfluoroalkylpolyethers,
CRC Handbook of Lubrication, Volume III,
Perfluoroalkylpolyethers , T. W. Del Pesco, CRC Press,
Boca Raton, FL pp. 287-303, 1994.
PFPE manufacturer bulletins: DuPont Company,Wilmington DE
800-424 7502
Worldwide web on Internet:
HTTP://WWW.KRYTOX.COM
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.
.
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F F| |
FCF FCFF F F | F F F | F F F F F| | | | | | | | | | | | |
FCCCOCCOCCOCCOCCOCCF| | | | | | | | | | | | |
F F F F F | F F F | F F FFCF FCF| |F F
K-CHAIN
The CF2O & CF2CF2O are shielded and by this could not be
attacked as easy as nonshielded CF2O groups
The CF2O & CF2CF2O are shielded and by this could not be
attacked as easy as nonshielded CF2O groups
The CF2O & CF2CF2O are shielded and by this could not be
attacked as easy as nonshielded CF2O groups
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Y-CHAIN
F F| |
FCF FCF
F | F F F F F | F F F F F F| | | | | | | | | | | | | |FCOCCOCOCCOCOCCOCOCCOCOCF| | | | | | | | | | | | | |F F F F | F F F F F | F F F
FCF FCF| |F F
The CF2O & are not completelyshielded and by this could be
more easily attacked thanshielded CF2O groups
The CF2O & are not completelyshielded and by this could be
more easily attacked thanshielded CF2O groups
The CF2O & are not completelyshielded and by this could be
more easily attacked thanshielded CF2O groups