Zinc dithiophosphate

They are soluble in nonpolar solvents, and the longer-chain derivatives easily dissolve in mineral and synthetic oils used as lubricants.

[3] Crankcase oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat-tappet camshafts and lifters which undergo very high boundary layer pressures and/or shear forces at their contact faces, and in other regions such as main bearings, and piston rings and pins.

[1] In-situ atomic-force microscopy (AFM) experiments show that the growth of ZDDP tribofilms increases exponentially with both the applied pressure and temperature, consistent with a stress-promoted thermal activation reaction rate model.

[5] Subsequently, experiments with negligible solid-solid contact demonstrated that film formation rate depends on the applied shear stress.

A wide variety of alcohols can be employed, which allows the lipophilicity of the final zinc product to be fine tuned.

[7] For example, zinc diethyldithiophosphate, Zn[(S2P(OEt)2]2, crystallizes as a polymeric solid consisting of linear chains.