Originally Posted By: Ben99GT
Originally Posted By: CompSyn
Originally Posted By: Ben99GT
Tangible proof, and easily verifiable with some searching.
Common, what's with the games? If you can help everyone with this ground breaking "proof", let's see it.
There's no games, I'm just surprised this isn't common knowledge around here by now. It's been covered so much now I didn't think anything more was required.
Originally Posted By: ExxonMobil
ESTERS
Organic esters used in synthetic lubricants are specifically designed to perform under operational extremes. They are the reaction products of a variety of alcohols and acids, which in turn lead to various ester types of predetermined molecular structure. Primarily oxygen-containing branched hydrocarbons that are thermally and oxidatively stable, these esters have high viscosity indices, and are free from undesirable and unstable impurities found in conventional petroleum-based oils. The esters are structurally differentiated from PAO due to the presence of multiple ester linkages (COOR) which impart polarity to the ester molecules. The polar nature of these esters drives many of their performance features, which include:
* Good thermal and oxidative stability that allows the ester to operate over a broad temperature range
* Low volatility and no volatile organic compounds, resulting in lower rates of evaporative loss
* Improved solvency, which leads to cleaner lubrication and/or improved additive solubility
* Lubricity that can enhance the performance of PAO or mineral oil- based lubricants
* Biodegradability features that allow formulation of products with environmental benefits.
Esters used in synthetic lubricants generally fall into five categories: Mono Esters, Dibasic Esters, Aromatic Esters (Phthalates and Trimellitates), Polyol Esters and Complex Polymeric Esters. ExxonMobil Chemical markets esters from each of the categories under the Esterex(TM) tradename, as shown in the product line chart.
It is generally recognized that polyol esters can enable a lubricant to achieve higher performance levels under extreme operating conditions. The differentiation chart shows how a unique Esterex polyol ester can offer performance advantages versus more conventional polyol ester.
The use of PAO and esters provides the formulator with a great deal of versatility in lubricant design. They can be used as the sole basestock for certain applications such as PAO in engine oils or esters in jet turbine lubes. They can also be used in combination with each other or with other less polar basestocks (e.g. mineral oils) to provide complementary performance. For example, esters are used with PAO to improve seal compatibility and provide additive solubility in a variety of automotive and industrial lubricant applications.
http://www.allbusiness.com/chemicals/petrochemicals-industry-petrochemicals/11436052-1.html
Esters are commonly added in small amounts to group III/IV oils to enhance additive solubility/solvency/seal swell/polarity.
Look at POEs used in refrigerants, there they are used
because of their extreme solvency. Group III actually isn't particularly solvent, perhaps moreso than PAO (when used by itself, which is almost never done) given Shell's statements, but I think they are splitting hairs there. Group III and PAO are actually the least polar of all the usual base oils.
Now scroll down to page 17 here:
http://www.synmaxperformancelubricants.c...resentation.pdf
TomNJ is the resident expert on esters, perhaps he will chime in.
Thank you. We're not in disagreement.
I've just been trying to clarify with you that a lubricant that is properly formulated whether it be from primarily Group III base stocks or from Group IV (PAO) base stocks can have equally as good or better characteristics over the other based on the Ester content or other additives used by the formulator.
So a properly formulated Group III formulation COULD be better than an improperly formulated Group IV (PAO).
And it goes both ways. A properly formulated Group IV (PAO) formulation COULD be better than an improperly formulated Group III oil.
That's the way I understand it from TomNJ. Quality base oils can influence the final finished product in some ways, but it's really the additives used that increase the performance quotient of a given motor oil.
Personally, I have nothing against Group III formulations, but since I can still get PAO formulations for pennies on the dollar more, I still prefer PAOs.
Thank God for free will and personal choice.