Patent ID: 6140280
Filing Date: 2000-10-31
Classification: C08F,C10M,C10N

Abstract:
A method for protecting 2-cycle diesel marine engines from corrosion and wear which comprises bringing components of said engine into contact with an effective amount of a lubricating oil composition which consists essentially of a base oil and (A) from 5 to 40% by weight of a metallic detergent-dispersant additive selected from over-based sulfonates, phenates and salicylates of alkaline earth metals and (B) from 0.1 to 3% by weight, relative to the total weight of the composition, of a reaction product of an acid compound of the following general formula (I) or (II) and a polyamine, selected from the group consisting of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, diethylene-triamine, triethylene-tetramine, tetraethylene-pentamine, pentaethylene-hexamine, dibutylene-triamine, tributylene-tetramine and pentapentylene-hexamine wherein the acid compound of formula (I) and (II) reacts with the polyamine in a molar ratio, acid compound/polyamine, of at least 3.0 and which give an absorption peak, .alpha.-peak, at 1640.+-.10 cm.sup.-1 and an absorption peak, .beta.-peak, at 1700.+-.10 cm.sup.-1 in the IR spectral pattern with the ratio of the intensity of the .alpha.-peak to that of the .beta.-peak, intensity of .alpha.-peak/intensity of .beta.-peak, being 0.27 or more: ##STR4## wherein R represents an alkenyl or alkyl group derived from a C2 to C15 olefinic polymer having a number-average molecular weight of from 500 to 3000.