1. High Performance Biodegradable Ester Lubricants from Sustainable and Non-Sustainable Feedstocks
Andrew P Swallow (Technical Service Manager)
John Eastwood (Technical Service Manager)
Steven J Randles (Global Applications Director) ã
Croda 2007
PRIOLUBE, PERFAD, HYPERMER, EMKAROX AND EMKARATE are trademarks of Croda

2. Agenda European ECO Labels Renewability Performance parameters
Natural esters
Oleochemical esters
Petrochemical esters

3. Existing Eco-labels in Europe
The European Eco-label has been based largely on the existing eco-labels of individual European countries, specifically:
Germany (Blue Angel)
Sweden (Swedish Standard)
Nordic Countries (White Swan)
France (NF Environment)
Holland (VAMIL Regulation)
Austria

4. An Eco-label for Europe
In December 2004 the European Commission voted in favour of adopting a European Eco-label for Lubricants.
The document was published in the Official Journal in the summer of 2005.
A copy of the document is available at:

5. Renewable Raw Materials
The lubricant shall have a carbon content derived from renewable raw materials that shall be:
=> 50% for hydraulic oils
=> 45% for greases
=> 70% for chain saw oils, concrete release agents and other total loss lubricants
=> 50% for two-stroke oils
Additive targets are difficult achieve
Biodegradability, bio-accumulation and toxicity targets are difficult to achieve while meeting the correct performance
Few formulations currently meet the criteria
A review of the European Eco-label will take place in 2008
Many of the European Eco-labels will continue in parallel

6. Lubricant Overview % Biodegradability 28 days OECD 301B % Renewability
content
Vegetable Oil
70 – 100
100
Mineral oil
20 – 40
PAO
20 – 60
Alkyl Benzene
5 - 20
Diesters
0 to 80
Aromatic ester
5 - 60
Polyol ester
0 to 85
Complex ester
Polyalkylene Glycol
Biodegradability tends to decrease with increasing chain length, branching, aromaticity and saturation, and will be influenced by the nature of the structure

7. Esters as Lubricant Base fluids
Three general categories
Natural oils and fats
Plant and animal derived
Oleochemical derived esters
Fatty unsaturated esters (e.g. oleates, dimerates)
Fatty saturated esters (e.g. stearates, isostearates)
Petrochemical esters
Diesters ( e.g. adipates, sebacates, azelates)

8. Oleochemical Derived Esters
Broad technology platform enabling the preparation of biodegradable esters with viscosities ranging from approximately 10cSt up to 1000cSt at 40°C
Not classified as dangerous for the environment, nor are they classified as harmful to aquatic organisms
Generally do not bio-accumulate in the environment. Typical esters used in the formulation of environmentally acceptable lubricants (EALs) have Log Kow values ranging from 10 to 25

9. Petrochemical Esters Diester advantages are :
Long-life lubricants
High temperature operating conditions
Very low temperature environments
In addition, diesters have a low viscosity. Until recently they have been the only real option for low viscosity lubricating oils
Diesters disadvantages are:
Non renewable
Under new Eco-label criteria, petrochemical esters will become useful only as co-base fluids and the amount that can be used in a formulation will be dictated by the application in which the lubricant will be used based on renewability

10. The Ester Reaction Alcohol + Acid Ester + Water Hydrolysis
R - OH
R1 - C - OH
R - O - C - R1
= O
H2O
= O
Alcohol + Acid
Ester + Water
Degree of Hydrolysis
High levels of water
Degree of Esterification
Low levels of water
- Catalyst
- Pressure
- Temperature
- Structure
Acid
Alcohol
Hydrolysis
Esterification

11. Improving Hydrolytic Stability
Esters are acid catalysed
Higher initial acid value the faster the breakdown
Tightly controlled manufacturing processes
Careful additive selection
Anti-wear additives (use stable and low acid value)
Anti-corrosion additives (neutral ones)
Acid catchers
Epoxides or carbo-imides

12. Performance Trade-Offs
Degree of branching
or aromaticity
100
Biodegradability
Hydrolytic Stability
Performance
O – C – C – = O
H2O
Steric
Hinderance
Polyol Ester

13. Performance Trade-Offs
Pyrolysis
Wax formation
100
Oxidative Stability
Performance
Low Temp Operability
Oxidation
Low
High
Hydrolysis
Natural Triglyceride
Iodine value

14. Optimizing Pour Point Low Temp Flow PE = Pentaerythritol
Ester
Pour Point, °C
TMP oleate (unsaturated C18)
-51
TMP stearate (saturated C18)
+45
TMP isostearate
-30
PE branched C9
+30
PE linear C9 +8
PE branched C8
Mixed branched PE
-38
Mixed linear and branched PE
-48
PE = Pentaerythritol
Low Temp Flow
- Molecular weight
- Degree of unsaturation
Structural diversity
Degree of branching
“Regular shaped structures” can flocculate and crystallize over time. Pour point is not always a particularly reliable measurement

15. Low Temperature Fluidity
Viscosity vs Storage time at - 30 °C
18000
16000
14000
12000
10000
TMPO
Viscosity (cSt)
8000
Modified
6000
4000
2000 50
100
150
200
Time (h)

16. Diester + Complex ester
ISO 46 Ester Comparison
Physical Property
Diester + Complex ester
Standard
TMP Oleate
Modified
Saturated
Polyol Ester
Opt. Ester
Ester A
Ester B
Ester C
Ester D
Ester E
Raw material source
Petro
Oleo
Viscosity at 40°C, cSt 46 48 44 45
Viscosity at 100°C, cSt
8.1
9.8
8.7 8
8.8
Viscosity Index
150
196
181
143
180
Viscosity at -30°C, cSt after 72hrs
9,500
5,500 to 16,000
3,800
4,400
Pour point, °C
-42
-51
-54
-45
Iodine value
<1 84 72 2
Dry TOST Test hours
(+1.5% RC9321)
>>4000
500
540
>>4,000
On test
>1,000
Biodegradability
28 days OECD 301B, % 61 99 85 77
Renewability, % 17 86 78
*Northern Europe would aim for <5,000 cSt at -30°C after 72hrs

17. Other Viscosities Oleo. derived Petro. Oleo Ester F Ester G Ester H
Ester I
Ester J
Ester K
Ester L
Viscosity 40°C, cSt 11 26 35 65
138
320
1040
Viscosity 100°C, cSt
3.0
5.3
7.5 13
17.6 90
Viscosity Index
136
139
193
208
140
150
167
Pour point, °C
-33
-54
-42
-21
-40
-24
Iodine value 1
<1 75 3 4
Dry TOST test hours
(+2% RC9308)
>4,000
500
Biodegradability
28 days OECD 301B, % 78 74 81 64 70 63
Renewability, % 85 88 73
Commercial high performance renewable esters have been developed for: Chain oils,
Greases, Transformer oils, MWFs, 2T, Fuel additives, Marine and Offshore applications

18. Conclusions
A wide range of esters commercially available that allow you to achieve optimum balance of
Biodegradability
Renewability
Stability
Low temperature properties
Cost
Careful selection of additives are required to optimise hydrolytic stability

19. Contact Andrew.Swallow@Croda.com +44 1642 435356 Wilton Centre
Redcar TS10 4RF
England
+ please add your details here

20. Disclaimer
The information in this publication is believed to be accurate and is given in good faith but no representation or warranty as to its completeness or accuracy is made.
Suggestions for uses or applications are only opinions. Users are responsible for determining the suitability of these products for their own particular purpose.
No representation or warranty, express or implied, is made with respect to information or products including without limitation warranties of merchantability or fitness for a particular purpose or non-infringement of any third party patent or other intellectual property rights including without limit copyright, trademark and designs.
Any trademarks identified herein are trademarks of the Croda group of companies