PURPOSE: A lubricating oil composition having wear resistance and extreme-pressure properties improved, by adding a specific organotin compound to a lubricating oil.
CONSTITUTION: An organotin compound represented by formula I, where R1 is alkyl; R2 is alkyl or a group represented by formula II; R3 is alkyl, alkenyl, cycloalkyl, alkoxyalkyl or benzyl; m is 1W3 and; n is 1W2, is added to the lubricating oil. In formula I, 1W12C alkyl is preferable as the alkyl of R1 and 1W18C alkyl as the alkyl of R2. In R3, 1W18C alkyl is preferable as the alkyl, 8W18C alkenyl as the alkenyl, 6W8C cycloalkyl as the cycloalkyl and 3W6C alkoxyl as the alkoxyl. Monomethyltin this (butylmercaptide), dibutyltin bis (octyl thioglycolate), etc. are mentioned as the organotin compound to be used.
ITSUKAICHI YOSHITOSHI
OONISHI HIDEMATSU
OGIWARA MICHIHIRO
MASAKI TETSUAKI
NIKKO CHEMICALS