STLE 2014 Paul Bonner Croda - Perfad 3100 initial results

www.crodalubricants.com
New Organic
Friction Modifiers for
Industrial Gear Oils
Paul Bonner

Outline
• Industrial gear oil (IGO) applications and technologies
• Benefits of friction reduction in IGOs
• Tribological testing of new IGO friction modifier
• Demulsibility and elastomer testing
• Further testing planned

Where are Industrial Gear Oils Used?
Wind turbines
Mining Mills (paper, textile, sugar)
Steel production

Wind Turbines
• Wind turbine gearboxes experience very high
contact pressures (Average 2.5 GPa)
• This generates high temperatures which places a lot
of thermal stress on the lubricant
• Wind turbine failures can be
catastrophic and are usually
caused by failure of the lubricant

Industrial Gearboxes
• The factories and mills where IGOs found are often hot and
humid where contamination is also a big issue
• Large gearboxes such as
those found in mills also
generate high torque values
• General trend is to smaller
gearboxes, higher loads and
more demand on the lubricant
and additives as the IGO runs
hotter

Types of Gears
• Different gears experience different lubrication regimes
• Most gears are a mixed sliding/rolling contact
• Hypoid gears and worm gears
have a higher proportion of sliding
in the contact and require more
EP and anti-wear additives
• Therefore formulation can be gear
specific
• Gear oils are available in a range
of viscosities from 32 to 1000 cSt
Hypoid
Worm

IGO Requirements
• Rejection of water – Water can
damage internal components
• Lower friction - Improved efficiency of
the gearbox
• Foam control – Foam inhibits film
formation
• Paint/Seal compatibility – Lubricant
must not degrade protective seals or
coatings

Base Oil Technologies
Ester Base Fluids
• Environmentally acceptable lubricants
• Good oxidative stability
• Very good VI
• Hydrolytic stability can be problematic
• Seal/Paint compatibility issues
PAO/Ester Formulations
• Good oxidative and hydrolytic stability
• Good wear protection
• Good VI
• Good water rejection
• Ester needed for additive solubility
Polyalkylene Glycol (PAG) Base Fluids
• Energy efficiency
• Very high VI
• Low traction coefficient
• Low deposits
• Readily mixes with water
Mineral Oil Base Fluids
• Low cost
• Medium VI
• Less oxidative/thermal stability
• Shorter oil drain intervals
• Higher chance of deposits

Friction Modifiers
• A reduction in friction is desirable as it reduces oil
sump temperatures (Even more important in smaller
gearboxes with less oil)
• This leads to less thinning of the lubricant and a thicker
oil film which helps to prevent wear
• Organic friction modifiers have traditionally
struggled to find applications in gear oils due to
their tendency to promote emulsification.
ASTM D1401 result for IGO + 1% GMO

“IGO – FM”
• IGO-FM is a new friction modifier for IGOs that has the
following advantages over conventional chemistries:
• Fully saturated - thermally and oxidatively stable
• Low impact on emulsification properties
• Sulphur, ash and phosphorus-free
• Strong reductions in friction at high temperatures and high loads
• IGO-FM is compliant with all major global inventories

Typical Physical Properties
IGO-FM
Acid value (mgKOH/g) 1.4
Appearance Light yellow
Biodegradability (OECD 301B) % >60
Cloud point ºC -14
Density @ 20ºC (g/ml) 0.97
Flash point (COC) ºC 275
Iodine value (gl/100g) 1.7
Kinematic viscosity @ 40ºC (mm2/s) 624
Kinematic viscosity @ 100ºC (mm2/s) 28
Phosphorus % 0
Physical form Liquid
Pour point ºC -15
Renewability % 100
Saponification value (mgKOH/g) 152
Sulphur % 0
Viscosity index 55

Performance Testing
• Tribological Testing
• MTM
• Stribeck curves (Friction vs speed)
• Variable load test (Friction vs contact pressure)
• HFRR
• Demulsification
• ASTM D1401

Testing formulations
• All testing done with commercially available additive
packages
• All initial screening tests: PAO + 10% ester + 1.65% commercially
available additive package to the viscosity quoted

MTM – Stribeck Curves
• The above profile was used to generate Stribeck
curves (friction vs. speed) for an ISO 68 industrial
gear oil
Parameter Value
Speed 0.01 - 2 m/s
Temperature 150ºC
Contact Pressure 1 GPa
Slide/Roll Ratio 50%
Specimens AISI 52100 steel

ISO 68 MTM Stribeck Curves (150 ̊C)
40-50% reduction in friction at low speeds using 1% IGO-FM
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.01 0.1 1 10
CoefficientofFriction
Speed (m/s)
IGO
IGO + 1% GMO
IGO + 1% IGO-FM

MTM – Variable Load Test
• PAO/ester base with 1.65%
addpack
• In this test, the speed was fixed at
0.05 m/s and the temperature
held at 100ºC
• Using a ball-on-disc, max. contact
pressure was 1.7 GPa
Parameter Value
Speed 0.05 m/s
Temperature 100ºC
Contact Pressure 0.65 – 1.7 GPa

ISO 220 MTM Variable Load (100 ̊C)
• 30-50% reduction in friction across a range of contact pressures
0
0.02
0.04
0.06
0.08
0.1
0.6 0.8 1 1.2 1.4 1.6
Contact Pressure (GPa)
ISO 220 IGO
ISO 220 IGO
+ 1% IGO-FM

• Strong performance also evident in higher viscosity fluids
0
0.02
0.04
0.06
0.08
0.1
0.6 0.8 1 1.2 1.4 1.6
ISO 320 IGO
ISO 320 IGO +
1% IGO-FM

MTM – Variable Load Test
• Using a barrel-on-disc
configuration much higher
contact pressures can be
achieved
Parameter Value
Speed 0.05 m/s
Temperature 100ºC
Contact Pressure 1.25 – 3.2 GPa

• Frictional benefits are maintained at higher loads when lubricating
films become thinner
0
0.02
0.04
0.06
0.08
0.1
1.25 1.65 2.05 2.45 2.85 3.25
ISO 220 IGO
ISO 220 IGO+
1% IGO-FM

• Frictional benefits are maintained at higher loads when lubricating
films become thinner
0
0.02
0.04
0.06
0.08
0.1
1.25 1.65 2.05 2.45 2.85 3.25
ISO 320 IGO
ISO 320 IGO +
1% IGO-FM

MTM Variable Load Test Summary
• Performance demonstrated in both ISO 220 and ISO
320 fluids
• Excellent performance at low loads / contact pressures
• Performance maintained at high loads
• Significant for heavily loaded gear systems such as wind
turbines, which can experience contact pressures around
2.5 GPa

HFRR Testing Profile
• The following test profile was used to investigate the
activity of IGO-FM in the HFRR
Parameter Value
Stroke Length 1000 µm
Frequency 20 Hz
Load 400 g (1 GPa)
Temperature 100ºC
Test Duration 1 hour

ISO 68 HFRR Friction Results (100 ̊C)
Almost 50% reduction in friction with IGO-FM
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0 1000 2000 3000 4000
Time (s)
IGO
IGO + 1% GMO
IGO + 1% IGO-FM

HFRR Wear Scar Results
40% reduction in wear achieved by addition of IGO-FM
0
50
100
150
200
250
300
IGO IGO + 1% GMO IGO + 1% IGO-FM
WearScar(µm)

Demulsification (ASTM D1401)
• Contact with water can lead to corrosion and loss of
performance
• The demulsification rig tests how readily the oil will reject
water, or whether it will instead form a stable emulsion.
5 Minutes
Mixing
30 Minutes
Standing Oil
Emulsion
Water

ISO 320 Demulsification Test – 30 mins
• IGO-FM creates a much less stable emulsion than GMO in two
different PAO/Ester based IGO formulations
Commercial addpack 1 Commercial addpack 2

Seal compatibility
• Initial elastomer volume change with 1% IGO-FM in
PAO + 10% ester was screened in-house
• Freudenberg FB 73 11 008 static and dynamic seal
compatibility test required for Flender approval
Elastomer type
NBR HNBR ACM FKM
% Volume Change with 1% IGO-FM 7.9 2 -0.2 0.6

Ester base

ISO 220 MTM Variable load test (100 ̊C)
• 30% reduction in friction seen in ester (ISO 220)
0.00
0.02
0.04
0.06
0.08
0.10
0.6 0.8 1 1.2 1.4 1.6
IGO
IGO + 1% IGO-FM

ISO 220 HFRR (100 ̊C)
• Reduction in friction also seen in ester (ISO 220)
HFRR
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0 10 20 30 40 50 60 70
Time (s)
IGO
IGO + 1% IGO-FM

HFRR Wear
217
198
0
50
100
150
200
WearScar(mm2)
IGO
IGO + 1% IGO-FM
• HFRR wear slightly lower with 1% IGO-FM

IGO-FM Summary
Base
Chemistry
MTM
friction
HFRR
friction
HFRR
wear
Demulsibility Seal
compatibility
PAO/Ester Up to
50%
reduction
50%
reduction
40%
reduction
Excellent Excellent
Ester 30%
reduction
10 – 20%
reduction
Slightly
reduced
Not tested Not tested
• Further testing planned
• Test performance in mineral oil and PAG*
• FZG
• Energy efficiency*
• Full elastomer testing

STLE 2014 Paul Bonner Croda - Perfad 3100 initial results

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