X - All Nadasdi1 - Synthetics Are Not the Same Presentation

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© 2006 Exxon Mobil Corporation. All rights reserved.

All Synthetic OilsAre Not The Same

Dr. T. Tim NadasdiDr. Jim T. Carey

Dr. Angela Galiano-Roth

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Introduction Synthetic lubricating oils have developed a reputation for working in the most extreme conditions. They have been associated with superior performance

thermal and oxidative stability shear stability low temperature performance low frictional properties

The evolution of mineral oil processing has recently led to the introduction of new families of products, marketed as synthetic lubricants

based on severely hydroprocessed mineral oils

This presentation will provide some insight into: fundamental characteristics of these “newer” synthetics compared to traditional synthetic oils effects that these base oils have on finished lubricant/grease performance

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API Basestock Classifications

API Basestock ClassificationPhysical Specifications

Group VI Sulfur % wt. Saturates % wtManufacturing

ProcessI 80-120 >0.03 <90 Conventional (solvent

refining)II 80-120 <0.03 >90 Require

Hydrocracking/dewaxingIII >120 <0.03 >90 Requires severe

Hydrocracking/dewaxingIV >140 0.00 >90 Chemical Synthesis -

PAOV All other synthetics -

esters, polyglycols,phosphate esters...

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Parameter Group I Group II Group III Group IVComparison of Basestock Properties

Oxidation Stability

Volatility

Additive Solvency of basestockLow Temperature capability

Efficiency / Traction

Relative costs 1 1.1-1.2 1.5 4 to 10Viscosity range at 40 deg C (in cSt) Up to 500 Up to 120 Up to 40 Up to 50,000

Direction of arrow indicates improved performance

Generalized Comparison of Base Stock Properties

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Mineral Oil Molecular Make-Up

PresentationSymbol

Chemical Advantage in aLubricant

Disadvantage in aLubricant

Short ChainParaffins

High volatility Low flash Pt.

Medium ChainParaffins

Higher VI Therm. & oxid. stability

Low solvency

Long ChainParaffins

High VI Therm. & oxid. stability

Low solvency Waxy

Aromatics High solvency High viscosity

Poor oxid. stability Low VI

HeteroatomicMolecules (S, N)

Sometimes oxidativestability

Can affect otherproperties (foam,Demuls, oxidation)

Saturated Rings Better low temp. Better solvency Adds some viscosity

Poor oxidativestability

A

H

R

Group I oils are a mixture of many different molecules with different properties R

R

R

H

HH

HHA

A

A

AA

A

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Mineral Oil Group I - Group III Processing

Hydroprocessing

FurtherHydroprocessing

R

R

R

H

HH

HH

A

A

A

AA

AGP I

R

R

RR

RRR

R

GP II

R

R

R

GP III

Polyalphaolephin (PAO)

Viscosity controlled by molecular design

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Basestock Summary

The processes used to manufacture Group II and Group III oils limit their viscosity to ~120 and 40 cSt at 40oC, respectively

Group II and Group III base oils require liquid thickening agents to meet the viscosity requirements of many industrial applications

PAO oils achieve their high viscosity through molecular design and do not require liquid thickening agents for typical industrial applications

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0

50

100

150

200

250

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Year

Cap

acity

(100

0 B

BL/

day)

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Group II

Group I

Total Capacity

86%

14% 29%

71%51%

49%

North American Base Oil Capacity Change

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Market Changes• 1999 ruling by the National Advertising Division of the Better Business Bureau has expanded the meaning of the word synthetic relative to lubricants

• Synthetic base oil compositions may include a variety of base oils that have been chemically altered and when formulated properly deliver the performance standards expected from a “synthetic” lubricant

• GP II, GP III and white oils may fit the new criteria for synthetics

•Increased North American market capacity for GP II & III oils

Practical Result - the meaning of the term synthetic has been expanded and can no longer be just associated with the performance strengths and chemistry of GP IV/V stocks.

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Let’s Look at 3 “Synthetic” Gear Oils

All 3 oils are considered synthetic hydrocarbons

The difference in the oils is in the blend of PAO, Polyisobutylene (PIB) and Group III base stocks

All other additives in the oils are the same

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Three Synthetic Gear Oils

1. The same commercial premium gear oil additive package in all oils2. The same commercially available ester in all oils

The oils differ ONLY in their base stock composition

Oil A Oil B Oil CHydrocarbon Type PAO PAO/PIB GP III/PIB

Viscosity ISO 460 ISO 460 ISO 460Viscosity Index 164 150 145

PAO 88 51Polyisobutylene (PIB) 37 37Group III Oil 51Gear Oil Additive Package1 2 2 2Ester2 10 10 10

Total 100 100 100

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Test Regiment

Bulk Oil Oxidation Test- This test is run for 24 hours at 375oF. Air is bubbled though the test oilwhich contains a metal catalyst. Viscosity increase and TAN are measured.

Worm Gear Test- This test involves running oils in a worm gear at various loads. It is run for48hrs during which time the oil temperature and gear box efficiency aremonitored. The used oil is tested for shear stablity (viscosity loss) and wearmetals.

Test Method Relation to Lubricant PerformancePour Point ASTM D97 In general, lower pour points indicate better low

temperature performance

Brookfield Visc ASTM D5133 Related to flowability and pumpability of oil at lower temperatures

Bulk Oil Oxidation See Below Estimation of oxidation stability and oil lifeWorm Gear Test See Below Shows lubricant performance in a real worm gear box

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Low Temperature Results - Pour Point

Even with PPD concentration optimized for lowest pour point, Oil C still has a pour point that is 9oC higher than PAO or PAO/PIB blends

Oil A(PAO)

Oil B(PAO/PIB)

Oil C(GP III/PIB)

Oil C+ PPD

-35

-30

-25

-20

-15

-10

-5

01 2 3 4

Deg

ree

Cel

sius

-33 oC

-24 oC

-18 oC

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0

100,000

200,000

300,000

400,000

500,000

600,000

-10 -20 -30

Temperature oC

Visc

osity

in c

P

Oil A(PAO)

Oil B(PAO/PIB)

Oil C(GP III/PIB)

Low Temperature Results - Brookfield Viscosity

Oil A shows significantly better flow characteristics at lower temperatures

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Bulk Oil Oxidation Results

Both TAN and viscosity increase indicate that Oil C undergoes the highest oxidation

0

5

10

15

20

25

% Change in Viscosity 7 7 23Change in TAN (mgKOH/g)

0.4 2.6 3.2

Oil A(PAO)

Oil B(PAO/PIB)

Oil C(GP III/PIB)

Visc

osity

Cha

nge

(%)

TAN

Cha

nge

(mg

KO

H/g

)

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Testing in a Worm Gear BoxWorm Gear

(Steel)

Bearings(Steel)

Driven Gear(Cu/Sn alloy)

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Gear Box Efficiency (%)

Oil A (PAO) has an average efficiency benefit of 6% over Oil C (GP III/PIB)

7071727374757677787980

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

Oil A(PAO)

Oil B(PAO/PIB)

Oil C(GP III/PIB)

Effic

ienc

y (%

)Worm Gear Test Results

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Sump Temperature (oF)

165170175180185190195200205210215

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

Tem

pera

ture

(o F)

Oil A(PAO)

Oil BPAO/PIB)

Oil CGpIII/PIB)

Oil A Oil B Oil CHydrocarbon Type PAO PAO/PIB GpIII/PIB

Viscosity Change - 1.8% - 4.8% - 5.9%Cu, ppm 70 320 1100Sn, ppm 25 42 160Fe, ppm 1 2 8

Used Oil Data

Worm Gear Test Results

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Oil Summary Group II oils are limited to ~120 cSt and Group III to ~40cStGroup II and Group III base oils require “thickening” agents to meet the viscosity requirements of many industrial applicationsSynthetic industrial lubricants made with Group II/III oils MAY have different performance properties than lubricants made with PAO aloneSelection of synthetic lubricants should focus on product performance, application requirements, and field experienceAll synthetics ARE NOT the same

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Considerations for Greases

Performance differences seen in oils will likely translate to greases

Need to understand grease lubrication regimes and determine which type of synthetic oil will perform best in the intended application

Different types of synthetic oils will likely interact differently with grease thickeners

Effect on bleed rate?Effect on shear stability?Effect on thickener reaction?Effect on low temperature properties?

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X - All Nadasdi1 - Synthetics Are Not the Same Presentation