Composition for hydraulic lubrication and coupling

A fan coupling composition which comprises:

• i) an organopolysiloxane having a viscosity of 1,000 to 20,000 cSt 25.degree. C.;
• ii) from 0.01 to 5%, by weight of the organopolysiloxane, of a phosphorous type anti-wear agent;
• and
• iii) from 0.01 to 2%, by weight of the organopolysiloxane, of an antioxidant;
• said phosphorous type anti-wear agent having one of the following formulae (I) to VII):
• ##STR8## wherein each of R.sub.1 to R.sub.4 is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms;
• each of R.sub.5 to R.sub.7 is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms;
• each of X.sub.1 to X.sub.4 is independently oxygen or sulfur;
• each Y is independently a direct bond, oxygen or sulfur;
• and n is an integer of from 0 to 2, with the proviso that both X.sub.2 and X.sub.3 are sulfur when n is 0;
• ##STR9## wherein R.sub.1 to R.sub.7, X.sub.1 to X.sub.4, Y and n are as defined in Formula (I);
• ##STR10## wherein each of R.sub.1 to R.sub.4 is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms;
• each of R.sub.5 and R.sub.6 is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms;
• each of X.sub.1 to X.sub.4 is independently oxygen or sulfur;
• each Y is independently a direct bond, oxygen or sulfur;
• and n is an integer of from 0 to 2;
• ##STR11## wherein each of R.sub.1 and R.sub.2 is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms;
• R.sub.8 is a hydrocarbon group containing from 1 to 20 carbon atoms and containing at least one ester bond;
• each of X.sub.1 and X.sub.2 is independently oxygen or sulfur;
• and each Y is independently a direct bond, oxygen or sulfur;
• (R--Y).sub.3 --P.dbd.X.sub.a (V)
• wherein each R-y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms;
• X is oxygen or sulfur;
• Y is oxygen or sulfur;
• and a is 0 or 1;
• (R--Y.sub.b).sub.3 --P.dbd.X.sub.a (VI)
• wherein each R-Y.sub.b group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms;
• X is oxygen or sulfur;
• Y is oxygen or sulfur;
• a is 0 or 1;
• and b is 0 or 1;
• ((R).sub.2 N).sub.a (RO).sub.b --P.dbd.X (VII)
• wherein each R.sub.2 N group and each RO group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms;
• X is oxygen or sulfur;
• a is an integer of from 1 to 3;
• and b is an integer of from 0 to 2, with the proviso that a+b=3.