Lubricant composition

The process of any one of the preceding claims, wherein a sulfur concentration provided by the one or more sulfur-containing additives, in total, ranges from about 75 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

The process of any one of the preceding claims, wherein the one or more antioxidants comprises N-α-naphthyl-N-phenylamine antioxidants of formula

• wherein
• R is H, C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, —C(O)C1-C18 alkyl or —C(O)aryl and R1, R2, R3 and R4 are each independently H, C1-C18 alkyl, C1-C18 alkoxy, C1-C18 alkylamino, C1-C18 dialkylamino, C1-C18 alkylthio, C2-C18 alkenyl, C2-C18 alkynyl or C7-C21 aralkyl.

The process of any one of the preceding claims, wherein the one or more antioxidants comprises diphenylamine antioxidants of formula

• wherein
• R is H, C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, —C(O)C1-C18 alkyl or —C(O)aryl and R1, R2, R3 and R4 are each independently H, C1-C18 alkyl, C1-C18 alkoxy, C1-C18 alkylamino, C1-C18 dialkylamino, C1-C18 alkylthio, C2-C18 alkenyl, C2-C18 alkynyl or C7-C21 aralkyl.

The process of any one of the preceding claims, wherein the lubricant composition comprises sulfur-containing additives selected from a group consisting of sulfur-containing hindered phenolic compounds, sulfur-containing rust inhibitors, sulfur-containing friction modifiers and sulfur-containing antiwear additives.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more sulfur-containing additives selected from a group consisting of 2,4-di-octylthiomethyl-6-tert-butylphenol, 2,4-di-octylthiomethyl-6-methylphenol, 2,4-di-octylthiomethyl-6-ethylphenol or 2,6-di-dodecylthiomethyl-4-nonylphenol, 2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol), 4,4′-thiobis(6-tert-butyl-3-methylphenol), 4,4′-thiobis-(6-tert-butyl-2-methylphenol), 4,4′-thiobis(3,6-di-sec-amylphenol), 4,4′-bis(2,6-dimethyl-4-hydroxyphenyl) disulfide, octadecyl 4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl 4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxy-benzylmercaptoacetate and esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid, β-(3,5-dicyclohexyl-4-hydroxyphenyl)-propionic acid, 3,5-di-tert-butyl-4-hydroxyphenylacetic acid or β-(5-tert-butyl-4-hydroxyphenyl)-3-thiabutyric acid with thiodiethylene glycol, 3-thiaundecanol or thiapentadecanol.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more sulfur-containing additives selected from a group consisting of organomolybdenum dithiocarbamates, organomolybdenum dithiophosphates and organomolybdenum compounds based on dispersants and molybdenum disulfide.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more sulfur-containing additives selected from a group consisting of sulfurized olefins, sulfurized vegetable oils, dialkyldithiophosphate esters, zinc dialkyldithiophosphates, alkyl or aryl di- or tri-sulfides, derivatives of 2,5-dimercapto-1,3,4-thiadiazole, ethyl(bisisopropyloxyphosphinothioyl)-thiopropionate, triphenyl thiophosphate, tris(alkylphenyl) phosphorothioates, diphenylmonononylphenyl phosphorothioate, isobutylphenyl diphenyl phosphorothioate, a dodecylamine salt of 3-hydroxy-1,3-thiaphosphetan 3-oxide, trithiophosphoric acid 5,5,5-tris-isooctyl 2-acetate, derivatives of 2-mercaptobenzothiazole, ethoxycarbonyl 5-octyldithiocarbamate and dihydrocarbyl dithiophosphate metal salts.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more sulfur-containing additives selected from a group consisting of sulfurized olefins.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more sulfur-containing additives selected from a group consisting of di-tert-alkyl polysulfides.

The process of any one of the preceding claims, wherein the lubricant composition comprises a base oil selected from a group consisting of Group II, Group III and Group IV base oils.

The process of any one of the preceding claims, wherein the lubricant composition comprises a base oil selected from a group consisting of polyalphaolefins.

The process of any one of the preceding claims, wherein the lubricant composition comprises a base oil selected from a group consisting of synthetic esters.

The process of any one of the preceding claims, wherein the lubricant composition comprises a base oil that comprises one or more polyalkylene glycols.

The process of any one of the preceding claims, wherein the lubricant composition comprises one or more N-α-naphthyl-N-phenylamine antioxidants and one or more diphenylamine antioxidants and wherein a weight/weight ratio of N-α-naphthyl-N-phenylamine antioxidants to diphenylamine antioxidants is from about 1/9 to about 9/1.

The process of any one of the preceding claims, wherein the lubricant composition comprises a base oil is an amount of from about 80 wt % to about 99.7 wt %, based on the total weight of the lubricant composition.

The process of any one of the preceding claims, wherein the lubricant composition comprises less than 0.1 wt % of zinc dialkyldithiophosphate salts, based on the total weight of the lubricant composition.

The process according to any one of the preceding claims, wherein a sulfur concentration provided by the one or more sulfur-containing additives, in total, ranges from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

The process according to any one of the preceding claims, wherein the lubricant composition comprises less than about 0.1 wt % overbased calcium, magnesium, salts of alkyl aromatic sulfonates, phenates, or salicylates, independently or in total, based on the total weight of the lubricant composition.

The process according to any one of the preceding claims, wherein the lubricant composition further comprises an ashless antiwear components, dispersants, pour point depressants, friction modifiers, and metal deactivators.

A system comprising an internal combustion engine and an ashless lubricant composition, wherein the ashless lubricant composition comprises:

• a base oil,
• one or more antioxidants selected from the group consisting of alkylated phenyl-naphthyl amines antioxidants, diphenylamine antioxidants, phenolic antioxidants, and combinations thereof, and
• one or more sulfur-containing additives.