upper possible VI limits on VII-free oils??

[dailydriver]

Can anyone guess (or actually KNOW) what the absolute upper limit on viscosity index would be for a viscosity index improver-free oil, made from the BEST, top grade, and optimal mix of group 4 and 5 basestocks? (NOT cost dependant, ability to be made at ANY price.)

Just curious.

Mola? Tom? Other actual tribologists on here?

 

[GMorg]

Fatty acid esters of trimethylolpropane can have a VI of >230 with viscosity of 9 cSt at 100C, but the pour point will only be -10C.

 

[dparm]

I too have seen information along those lines: VIs well over 200 but not suitable as the "only" ingredient in a motor oil.

 

[ARCOgraphite]

Just as a ref point, below is a Chevron 9cSt PAO data sheet; note the 2.2% noack:

haht.product_family: PAO, haht.content_type: TDS, cpchem.advancedSearch.section: =strFinalString%>
Synfluid® PAO 9 cSt
Highly Branched Isoparaffinic Polyalphaolefin
Application Synfluid® 9 cSt PAO can be used in many industrial and automotive lubricant applications. These include gear oils, compressor
oils, engine oils, hydraulic fluids, greases, and other functional fluids.
Handling Maximum temperatures of 65 ºC (149 ºF) for handling and ambient for long-term storage are recommended. For specific
instructions on handling, see MSDS.
Typical Properties
Property Typical Value
Kinematic Viscosity, cSt @ 212°F, 100°C 9.0
Kinematic Viscosity, cSt @ 104°F, 40°C 53.9
Kinematic Viscosity, cSt @ -40°F, -40°C ----
Viscosity Index 146
Pour Point, °F, °C -33 (-36)
Flash Point (COC), °F, °C 529 (276)
Fire Point (COC), °F, °C 581 (305)
Volatility, Noack, wt% 2.2
Specific Gravity, 60°/60°F, 15.6°/15.6°C 0.8343
Density, lb/gal 6.947
Total Acid Number Bromine Index Odor No Foreign Odor
Appearance Clear and Bright

 

[CATERHAM]

Well Tom_NJ, who would know, mentioned recently that of base oils suitable for motor oil use, esters have the highest VIs topping out at 180. I was a bit surprised that light PAOs only have VIs up to about 145.

The highest VI finished oil that I know of that contains no polymer thickeners, is FUCHS Titan GT-1 XTL 0W-20. It's ester based and has a VI of 172.

 

[Tom NJ]

Originally Posted By: GMorg
Fatty acid esters of trimethylolpropane can have a VI of >230 with viscosity of 9 cSt at 100C, but the pour point will only be -10C.


The TMP esters with VIs over 200 are made with oleic acid which has unsaturation (double bonds), making the oxidative stability poor.

Among saturated highly stable esters, dodecanedioates (based on a C12 dibasic acid) can get up to about 180 VI. They also have suitable viscosities, very low pour points, and very high lubricity, but are quite expensive with limited commercial availability. Ideal for blending with PAOs, especially PAOs based on 1-dodecene when cost is no object. Unfortunately cost is always an object.

Some complex esters can get up to the 160s or 170s but usually at the cost of pour point, and they tend to have too high viscosities.

POEs, PAOs, and Group III+ in the correct viscosity range usually cap out at about 140ish.

Keep in mind that the DI package and pour point depressant will also affect the VI.

Tom NJ

 

[CATERHAM]

Tom what about the maximum VIs for POE?
I'm of course thinking of Red Line and the polymer free 0W-20 which has a 166 VI.
Since RL claims to be a a POE/PAO blend that doesn't leave much room for any low VI carrier DI oil or much PAO to speak of.

 

[buster]

BOOM! Thanks Tom!

 

[Shannow]

It's threads like these that I'd like to see have a rating/karma/found useful option on the board.

 

[d00df00d]

What a breath of fresh air this thread is.

Tom, what exactly is "the DI package" and how does it affect VI?

 

[Tom NJ]

Originally Posted By: CATERHAM
Tom what about the maximum VIs for POE?
I'm of course thinking of Red Line and the polymer free 0W-20 which has a 166 VI.
Since RL claims to be a a POE/PAO blend that doesn't leave much room for any low VI carrier DI oil or much PAO to speak of.


There are many kinds of POEs, TMP being one. The longer the acid in POEs, the higher the VI. Usually the longest acids esterified onto a TMP or PE type POE to give a stable ester with a good pour point are nC8 and nC10. Saturated acids above this chain length causes the ester to rapidly develop a freeze point. TMP C8C10 has a VI of 140, a viscosity @ 100°C of 4.3 cSt, and a pour point of -65°F, and is a popular POE for motor oils. You can push the VI of POEs higher with long chain unsaturated acids like oleic but lose the oxidative stability. Complexing or polymerizing the POE will also increase the VI but the viscosity goes up too high for a motor oil. The types of POEs that are generally used in 0W-X or 5W-X oils pretty much cap out at about 140 VI, although we did push an NPG type up to about 150 by coesterifying the C8C10 aid with a saturated branched long chain acid.

Sometimes POEs exhibit a VI synergy when blended with high viscosity PAOs, that is the VI of the blend is well above the arithmatic plot. High viscosity PAOs are very shear stable thickeners with a much lower molecular weight than typical polymeric VI Improvers.

Tom NJ

 

[Tom NJ]

Originally Posted By: d00df00d
What a breath of fresh air this thread is.

Tom, what exactly is "the DI package" and how does it affect VI?


The DI package (detergent-inhibitor package) is a cocktail of additives produced by the additive companies that is ready to be blended with the base oils and VI Improvers to make the finished oil. It includes dispersants, detergents, ZDDP, anti-oxidants, rust and corrosion inhibitors, friction modifiers, anti-foam, etc. The dispersants are the largest component of the package and have a polymeric backbone which I would expect to raise the VI, but I don't know the net effect of the total package as the additive companies do not report the VI. The pour point depressant is also polymeric and it does raise the VI, although they are not really needed in oils based only on PAO and esters. The DI package is a thick liquid that certainly contributes to viscosity, and I would expect it to raise the VI as well, but I never measured its effect.

Tom NJ

 

[Primus]

Originally Posted By: CATERHAM
The highest VI finished oil that I know of that contains no polymer thickeners, is FUCHS Titan GT-1 XTL 0W-20. It's ester based and has a VI of 172.


If to believe PDS dd. 2003 from Fuchs and dd. early 2009 from a german seller, as well german studies dd. 2006, at this time GT-1 had VI = 160. The PDS dd. 2010 already shows VI = 172. It's known that since 2003 Fuchs changed composition at least 1 time. It's also known that in 2006 it was 50% hydrocarbon and 50% ester based. As for XTL version I met two versions of PDS: one still shows 172, but another shows again 160. XTL also shows higher NOACK 7.5% vs. 6.9% with non-XTL version.

 

[Sam_Julier]

What a breath of fresh air this thread is.

This thread is why I spend way too much time on BITOG.

 

[A_Harman]

I have learned a lot about the chemistry and formulation of motor oils by going through TomNJ's old posts.

 

[OVERKILL]

Originally Posted By: d00df00d
What a breath of fresh air this thread is.

Tom, what exactly is "the DI package" and how does it affect VI?


Agreed! Great thread

 

[CATERHAM]

Originally Posted By: Tom NJ
Originally Posted By: CATERHAM

Sometimes POEs exhibit a VI synergy when blended with high viscosity PAOs, that is the VI of the blend is well above the arithmatic plot. High viscosity PAOs are very shear stable thickeners with a much lower molecular weight than typical polymeric VI Improvers.Tom NJ

If the maximum VI of a PAO base oil is 140 I presume you're not including the use of high viscosity, very high VI PAOs that are used instead of polymeric thickeners to raise the net VI of a finished oil?
Tom, would products like EOMs SpectraSynElite 150 (206 VI) and SpectraSynElite65 (179 VI) be examples of these possible polymer substitutes?
http://www.exxonmobilchemical.com/Chem-E...datasheets.aspx

Another point. Since the DI package can make up a significant percentage by volume of a finished oil and the single largest component are the dispersants which have a polymeric bachbone and therefore are effectively a VI improver. I presume one could conclude that their are no finished oils that are truly polymer VII free?

 

[Tom NJ]

Originally Posted By: CATERHAM
If the maximum VI of a PAO base oil is 140 I presume you're not including the use of high viscosity, very high VI PAOs that are used instead of polymeric thickeners to raise the net VI of a finished oil?
Tom, would products like EOMs SpectraSynElite 150 (206 VI) and SpectraSynElite65 (179 VI) be examples of these possible polymer substitutes?
http://www.exxonmobilchemical.com/Chem-E...datasheets.aspx

Yes the PAO VIs I noted are for PCMO base oils (4 cSt and 6 cSt). The high viscosity PAOs you linked are used at low additive levels, usually
Originally Posted By: CATERHAM
Another point. Since the DI package can make up a significant percentage by volume of a finished oil and the single largest component are the dispersants which have a polymeric bachbone and therefore are effectively a VI improver. I presume one could conclude that their are no finished oils that are truly polymer VII free?

DI packages are usually dosed at about 10-15% in PCMOs and are about 40-50% dispersants. Yes I would agree that all modern motor oils contain some polymer content, but the dispersant backbones are not as large as VI Improvers, and not as subject to shearing. I don't consider VI Improvers and shearing to be as negative as many here perceive. Most 5w30s only lose about a centistoke of viscosity at 100°C from shearing (plus or minus a little), which is not an issue. So long as the formulation is fully engine tested and meets the desired specs, no worries.

Here is some more information on DI packages and dispersants:

DI Packages

Tom NJ

 

[GMorg]

The TMP ester to which I was referring uses lard (pig fat) as the fatty acid source. The fatty acids are of mixed length and mostly saturated. However, oxidation stability is still an issue.

 

[Tom NJ]

Originally Posted By: GMorg
The TMP ester to which I was referring uses lard (pig fat) as the fatty acid source. The fatty acids are of mixed length and mostly saturated. However, oxidation stability is still an issue.


Interesting - who is producing this?

Lard has more saturated fatty acids than most vegetable oil sources but is still very high in oleic. Coconut and palm kernel fatty acids have the highest saturated fat content, but like lard would have a pour point problem and produce too high of a viscosity for low W grade PCMOs.

Tom NJ