Abstract Mineral lubricating oil compositions are prepared containing sludge dispersing amounts of conventional ashless dispersants and, optionally, their sulfurized derivatives, and also containing sludge inhibiting or oxidation inhibiting amounts of sulfurized oil-soluble pour point depressant type organic compounds. The ashless dispersants used are the polyalkylene polyamine condensation products of alkenyl succinic acids or anhydrides or of alkenyl substituted lower fatty acids wherein the alkenyl radical is of C40 to C250 length used either alone or along with their sulfurized derivatives. The pour point depressants are those heretofore conventionally used but in their sulfurized form, such as sulfurized wave alkylated naphthalene, sulfurized polymeric long chain alkyl esters of acrylic or methacrylic acids.
A lubricating oil composition as defined by claim 1 wherein said sulfurized ester and said ashless dispersant are each present in a concentration between about 0.05 and about 10 wt. percent of the total composition.
Claim 2
Dependent Claim
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A lubricating oil composition as defined by claim 1 which also contains a minor sludge inhibiting amount of at least one sulfurized ashless dispersant wherein said ashless dispersant is as set forth in claim 1.
Claim 3
Dependent Claim
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A lubricating oil composition as defined by claim 1 wherein said sulfurized polymeric ester is a sulfurized polymeric mixed C12-C18 alkyl methacrylate.
Claim 4
Dependent Claim
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A lubricating oil composition as defined by claim 1 wherein said polyalkylene polyamine is tetraethylene pentamine.
Claim 5
Dependent Claim
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A lubricating oil composition as defined by claim 1 wherein said alkenyl radical is polyisobutenyl.
Claim 6
Dependent Claim
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A lubricating oil composition as defined by claim 1 wherein said ashless dispersant is the condensation product of tetraethylene pentamine and polyisobutenyl succinic anhydride.