Lubricating oil composition

A lubricating oil composition comprising

• (1) 100 parts by weight of a polycarbonate represented by the following general formula (II),
• (2) 0.0002-5 parts by weight of a triester phosphite compound (e), and
• (3) 0-5 parts by weight of at least one compound selected from the group consisting of a triester phosphate compound (f), an epoxy compound (a) and a phenol compound (b),
• Su-O-R (II)
• wherein Su is a group represented by the following formula (A), and R is a group selected from the groups represented by the following formulae (B), (C), (D), (E) and (F), ##STR10## in which R.sub.4 is a group represented by the above-mentioned formula (E) or (F), wherein R.sub.5 each is independently a hydrocarbon group having not more than 30 carbon atoms or a hydrocarbon group containing an ether bond and having 2 to 30 carbon atoms, an n and p are each an integer of 1 to 12.

A lubricating oil composition comprising

• (1) 100 parts by weight of a polycarbonate represented by the following general formula (III),
• (2) 0.0002-5 parts by weight of a triester phosphite compound (e), and
• (3) 0-5 parts by weight of at least one compound selected from the group consisting of a triester phosphate compound (f), an epoxy compound (a) and a phenol compound (b), ##STR11## wherein R.sub.4 is a group represented by the following formula (E) or (F), and m is an integer of 1 to 6,
• -(C.sub.3 H.sub.6 O).sub.n COOR.sub.5 (E)
• -(C.sub.3 H.sub.6 O).sub.n (C.sub.2 H.sub.4 O).sub.p COOR.sub.5(F)
• wherein R.sub.5 is independently a hydrocarbon group having not more than 30 carbon atoms or a hydrocarbon group containing an ether bond and having 2 to 30 carbon atoms, an n and p are each an integer of 1 to 12.

A lubricating oil composition comprising

• (1) 100 parts by weight of a polycarbonate represented by the following general formula (I),
• (2) 0.0001-5 parts by weight of a phenol compound (a), and
• (3) 0.0001-5 parts by weight of dilauryl thiodipropionate or 4,4'-thio-bis (3-methyl-6-t-butylphenol
• R.sub.1 OCOO(R.sub.2 O).sub.p COO).sub.n R.sub.3 (I)
• wherein R.sub.1 and R.sub.3 each are independently a hydrocarbon group having not more than 30 carbon atoms or a hydrocarbon group containing an ether bond and having 2 to 30 carbon atoms, R.sub.2 is an alkylene group having 2 to 24 carbon atoms, p is an integer of 1 to 100, and n is an integer of 1 to 10.

A lubricating oil composition comprising

• (1) 100 parts by weight of a polycarbonate represented by the following general formula (I),
• (2) 0.0001-5 parts by weight of a phenol compound (a), and
• (3) 0.01-5 parts by weight of a triester phosphite compound (e)
• R.sub.1 OCOO(R.sub.2 O).sub.p COO).sub.n R.sub.3 (I)
• wherein R.sub.1 and R.sub.3 each are independently a hydrocarbon group having not more than 30 carbon atoms or a hydrocarbon group containing an ether bond and having 2 to 30 carbon atoms, R.sub.2 is an alkylene group having 2 to 24 carbon atoms, p is an integer of 1 to 100, and n is an integer of 1 to 10.