Olefin sulfide: What is it?

[Big O Dave]

I was looking at the MSDS for Shell Spirax EW gear oil, and Olefin sulfide is one of ingredients.

I know that many gear oils use sulphur/phosphorus compounds as their EP, and Chevron uses borates in Delo Gear Oil, but I haven't seen Olefin sulfide before. I did a Google search and found it is also used in Redline gear oils, so it can't be too bad, right?

If anyone can provide more info on this, and the pros and cons of the different EP additives, I would greatly appreciate it.

Thanks, in advance!

 

[bruce381]

Sulfurized Olefins are used in most all high quality gear oil packages along with various other compounds, Amine phosphates have a good synergy with sulfur and works also as a rust inhibitor. Borate also works well in gear oils but needs Sulfur to help with shock loading as I remember borate alone will not work well in a
GL-5 gear oil and potasium tri/tetra borate has a water soluble problem that used to cause a salt/deposit buildup on seals and would cut the seal causeing leaks, that was years ago and may have improved now.
bruce

 

[MolaKule]

Sulferized olefins or Olefin Sulfides are one of the main Extreme Pressure ingrediants in heavy duty gear lubes, with phosphate esters being another.

In sulferized olefins, one takes a hot batch of high viscosity olefin, adds a dispersant, and dissolves sulfur in it. To make it inactive or non-corrosive to copper alloys such as brass and bronze, one adds a metal deactivator or other chemical compound to it. This allows sulfur to still act as an EP agent but keeps the sulfur from corroding yellow metals.

Most EP gear lube additives comes complete with a mix of sulferized olefin, phosphate ester, corrosion inhibitor, metal deactivator, and an anti-wear agent such such as ZDDP or other "organo-metallic" compound.


You can see the basic molecular building blocks (monomers) for the various olefins here:

http://www.csuchico.edu/~jpgreene/itec041/m41_ch06/sld003.htm

 

[Big O Dave]

Thanks, guys! My brain now hurts, but I think I get it.

How does the borate-based compound in Delo Gear Lube compare to this olefin sulfide compound, in terms of preventing wear?

 

[bruce381]

Boron is a very good film former and works very well in lighter vis grades down side is water in tolorance so use in a wet gear box is a bad idea. Otherwise the boron delo gear lube is a very long life lube which in my mind offers synthetic like performance.
bruce

 

[Big O Dave]

Thank you, Bruce

 

[blingo]

Were the Olefin Sulfides always unusual in engine oils or just mostly replaced? Replaced with the ORGANO MOLY-SULFUR COMPLEXes that other Delvacs contain? This seems to be one of very few SDS showing them:

 

[M56959]

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