The Action of Multicomponent Additives

The simplest concept of a multicomponent additive is a straightforward mixture of individual additives each of which contains a single key active element, and in fact many multicomponent additives are just that. But since it is logically possible to have more than one type of key functional group in the same molecule, this is another kind of multicomponent additive to consider. There is a fundamental difference between a multifunctional additive compound of this kind and the additive structure with more than one key element but only a single functional group, such as is found in the zinc dialkyl dithiophosphates Zn[SP(S) (OR 2]2 dithiophosphate esters of the type RS-P(S) (OR)2  

TABLE 11-21. INFLUENCE OF SULFUR IN STRUCTURE OF THIOPHOSPHITE AND THIOPHOSPHATE ESTERS ON THEIR ADDITIVE ACTION 

Additives 0.006 mole in 100 grams base oil. Four-ball test at 600 rpm. From data by Sanin, Shepeleva, Ulyanova and Kleimenov [42]. 

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