Chlorine-free silver protective lubricant composition (I)

An internal combustion engine lubricating composition comprising a major proportion of an oil of lubricating viscosity and (1) a minor amount of a silver protective additive composition comprising at least one member selected from the group consisting of:

• (A) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid and
• (i) compounds having the general formula:
• ##STR14## wherein X is NR.sub.1, O, or S, and R.sub.1 is H or C.sub.1 to C.sub.15 hydrocarbyl and R.sub.2 is H, --NR'R", or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl and R' and R" (being the same or different) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• or (ii) salts of said compounds;
• (B) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid and at least one amine selected from the group consisting of (i) mono-amines having the formula HNRR where R and R' (being the same or different but not both H) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and (ii) alkylene diamines having the general formula:
• ##STR15## wherein n=2 to 10, and R.sub.1 and R.sub.2 (being the same or different) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and (iii) polyalkylene polyamines having the general formula:
• ##STR16## wherein A is a divalent alkylene radical having 2 to 6 carbon atoms;
• x is an integer from 1 to 10;
• and R is H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• (C) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid and derivatives of glycine having the general formula:
• ##STR17## wherein R is H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and R' and R" being the same or different are H or C.sub.1 to C.sub.20 hydrocarbyl;
• (2) a minor amount, effective for dispersancy, of an ashless dispersant;
• and (3) a minor amount, effective for detergency, of at least one detergent selected from the group consisting of alkali and alkaline earth metal sulfonates, phenates and salicylates.

A method for protecting silver engine parts in an internal combustion engine which method comprises the step of contacting the internal portion of said engine with a lubricating composition comprising a major proportion of an oil of lubricating viscosity and a minor amount of a silver protective additive comprising at least one member selected from the group consisting of:

• (A) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid and (i) compounds having the general formula:
• ##STR23## wherein X is NR.sub.1, O, or S;
• where R.sub.1 is H or C.sub.1 to C.sub.15 hydrocarbyl and R.sub.2 is H, or --NR'R', or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl and R' and R" (being the same or different) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• or (ii) salts of said compounds;
• (B) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid and at least one amine selected from the group consisting of (i) mono-amines having the formula HNR'R" where R' and R" (being the same or different but not both H) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and (ii) alkylene diamines having the general formula:
• ##STR24## wherein n=2 to 10, and R.sub.1 and R.sub.2 (being the same or different) are H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and (iii) polyalkylene polyamines having the general formula:
• ##STR25## wherein A is a divalent alkylene radical having 2 to 6 carbon atoms;
• X is an integer from 1 to 10;
• and R is H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• (C) the reaction product of a C.sub.5 to C.sub.60 carboxylic acid with derivatives of glycine having the general formula:
• ##STR26## wherein R is H or C.sub.1 to C.sub.20 hydrocarbyl or hydroxy-substituted hydrocarbyl;
• and R' and R" (the same or different) are H or C.sub.1 to C.sub.20 hydrocarbyl.