Lubricating oil compositions containing poly(oxyalkylene) aminoether carbamates as dispersing agents

#This application relates to lubricating oil compositions containing hydrocarbylpoly(oxyalkylene) aminohydrocarbyloxyhydrocarbyl carbamates which contribute dispersancy and detergency to the compositions.

#Lubricating oil compositions, particularly for use in internal combustion engines, have long performed many functions other than simply lubricating moving parts. Modern-day, highly compounded lubricating oil compositions provide antiwear, antioxidant, extreme-pressure and anti-rust protection in addition to maintaining the cleanliness of the engine by detergency and dispersancy. Many lubricating oil additives are well known for accomplishing these functions. For maintaining engine cleanliness, a well-known class of ashless detergents which have been found to be particularly useful are poly(oxyalkylene) carbamates. U.S. Pat. Nos. 4,160,648 and 4,247,301 disclose and claim fuel compositions containing certain poly(oxyalkylene) aminocarbamates and poly(oxyalkylene) polyamines as deposit control additives. While, in general, deposit control additives are not believed to be useful dispersants for lubricating oil compositions, certain aminocarbamates and certain polyamines are useful in this regard.

#It has been found that improved lubricating oil compositions comprise a major amount of an oil of lubricating viscosity and an amount sufficient to provide dispersancy of hydrocarbylpoly(oxyalkylene) aminohydrocarbyloxyhydrocarbyl carbamates of molecular weight from about 500 to about 10,000, and preferably from about 500 to about 5,000 and having at least one basic nitrogen atom; wherein said poly(oxyalkylene) moiety is composed of oxyalkylene units selected from to 2 to 5 carbon oxyalkylene units and containing at least sufficient branched-chain oxyalkylene units to render said carbamate soluble in said lubricating oil composition. The poly(oxyalkylene) moiety is hydrocarbyl-terminated or "capped" and is bonded through a carbamate linkage or connecting group to an aminohydrocarbyloxyhydrocarbyl moiety ordinarily comprising an amino group at either end of said moiety separated by ether sub-moieties containing from between 2 to 60 carbon atoms and from 1 to 10 oxygen atoms .

#The present invention herein consists of a poly(oxyalkylene) aminoether carbamate, and a lubricating oil composition containing a major amount of oil of lubricating viscosity and from about 0.01 to about 5 weight percent of said additive. The poly(oxyalkylene) amino-ether carbamate has a molecular weight of from about 500 to about 10,000 and preferably from about 500 to about 5,000. The composition consists of three parts or moieties. One is the aminohydrocarbyloxyhydrocarbyl moiety, the second is the poly(oxyalkylene) moiety comprising at least one hydrocarbyl-terminated poly(oxyalkylene) polymer, bonded together through the third moiety or connecting group, a carbamate linkage, i.e., ##STR1##

#As a dispersant, the poly(oxyalkylene) moiety and the aminoether moiety are selected to provide solubility in the oil composition and dispersant activity without contributing to deposit formation. The additives may be termed hydrocarbylpoly(oxyalkylene) aminohydrocarbyloxyhydrocarbyl carbamates, or for convenience, "polyether aminoether carbamates". The additives may be prepared from the reaction of a poly(oxyalkylene)chloroformate with the appropriate diaminoether such as 4,9-dioxadodecane-1,12-diamine to form the active composition.

#The hydrocarbyl-terminated poly(oxyalkylene) polymers which are utilized in preparing the carbamates of the present invention are monohydroxy compounds, i.e., alcohols, often termed monohydroxy polyethers, or polyalkylene glycol monohydrocarbylethers, or "capped" poly(oxyalkylene) glycols and are to be distinguished from the poly(oxyalkylene) glycols, or polyols, which are not hydrocarbyl-terminated, i.e., not capped. The hydrocarbyl-terminated poly(oxyalkylene) alcohols are produced by the addition of lower alkylene oxides, such as oxirane, ethylene oxide, propylene oxide, the butylene oxides, or the pentylene oxides to the hydroxy compound ROH under polymerization conditions, wherein R is the hydrocarbyl group which caps the poly(oxyalkylene) chain. Methods of production and properties of these polymers are disclosed in U.S. Pat. Nos. 2,841,479 and 2,782,240, and Kirk-Othmer's "Encyclopedia of Chemical Technology", Volume 19, p. 507. In the polymerization reaction, a single type of alkylene oxide may be employed, e.g., propylene oxide, in which case the product is a homopolymer, e.g., a poly(oxypropylene) propanol. However, copolymers are equally satisfactory and random copolymers are readily prepared by contacting the hydroxyl-containing compound with a mixture of alkylene oxides, such as a mixture of propylene and butylene oxides. Block copolymers of oxyalkylene units also provide satisfactory poly(oxyalkylene) polymers for the practice of the present invention.