US3784474A - Lubricating oil composition - Google Patents

Abstract

A LUBRICATING OIL COMPOSITION CONTAINING A HYDROCARBYL SUBSTITUTED AMINE ASHLESS DETERGENT WHERE THE HYDROCARBYL SUBSTITUENT CONTAINS AT LEAST 40 CARBON ATOMS, A POLYOXYALKYLENE DERIVATIVE, AND AN ALKALINE EARTH METAL CARBONATE DISPERSED IN THE OIL TO PROVIDE AN ALKALINITY VALUE OF ABOUT 10 MG. KOH/G. THESE COMPOSITIONS ARE FOUND TO BE HIGHLY RUST AND CORROSION INHIBITORY WHILE ALSO POSSESSING THE ABILITY TO REDUCE OR PREVENT THE FORMATION OF VARNISH, SLUGE AND DEPOSITS ON THE INNER METALLIC SURFACES OF INTERNAL COMBUSTION ENGINES. THE PREFERRED POLYOXYALKYLENE DERIVATIVES ARE THE POLYXYALKYENE POLYOLS OR OXAALKANOLS.

Description

3,784,474 LUBRICATING OIL COMPOSITION Stuart Houston Brown, San Rafael, and Warren Lowe,

El Cerrito, ,Calih, assignors to Chevron Research Company, San Francisco, Calif. No Drawing. Filed Mar. 13, 1972, Ser. No. 234,398

Int. Cl. C10m 1/32 U.S. Cl. 252--51.5 R 9 Claims ABSTRACT OF THE DISCLOSURE A lubricating oil composition containing a hydrocarbyl substituted amine ashless detergent where the hydrocarbyl substituent contains at least 40 carbon atoms, a po1yoXyalkylene derivative, and an alkaline earth metal carbonate dispersed in the oil to provide an alkalinity value of about 10 mg. KOH/ g. These compositions are found to be highly rust and corrosion inhibitory while also possessing the ability to reduce or prevent the formation of varnish, sludge and deposits on the inner metallic surfaces of internal combustion engines. The preferred polyoxyalkylene derivatives are the polyoxyalkyene polyols or oxaalkanols.

BACKGROUND OF THE INVENTION Field of the invention Lubricating oils are employed both for lubrication and as a vehicle for additives which promote the protection of the metallic surfaces being lubricated. These surfaces must be protected from both rust and corrosion, and from the deposition of varnish and sludge. These functions are performed by lubricating additives, which are, unfortunately, sometimes antagonistic. Specifically, a lubricating oil containing dispersed alkaline earth metal carbonate for the neutralization of acid and the prevention of corrosion and rust may be debilitated and degraded in its antirust performance by the addition of basic nitrogenous ashless detergent.

It was an object of this invention to find a lubricating oil composition of an ashless detergent and a phenate or sulfonate dispersed alkaline earth metal carbonate with a possible third additive which would serve to prevent antagonistic degradation of antirust performance While still permitting the full dispersant and detergent activity of the ashless detergent to go unchecked. Quite surprisingly, a class of such third additives was discovered which not only prevents antagonistic degradation of antirust performance, but actually enhances the rust inhibitory capacity of the lubricating oil composition. This class comprises the presence in very small amounts (0.01- percent by weight) of polyoxyalkylene compounds or derivatives, and preferably polyoxyalkylene polyols and polyoxyalkylene glycols, of molecular weight in the range from about 1,000 to about 20,000. In laboratory tests, the class of polyoxyalkylene derivatives do not function as rust inhibitors when present alone in lubricating oils, or even when present in conjunction with ashless detergents. However, polyoxyalkylene derivatives do act in combination with dispersed alkaline earth metal carbonate in the presence of ashless detergents in lubricating oils to greatly improve rust inhibition in engines.

Description of the prior art The hydrocarbyl substituted polyamines are taught as dispersant/detergents by Honnen and Anderson in U.S.

Pats. 3,565,804, 3,438,757 and 3,574,576. Polyoxyalkylene polyols were taught as demulsifiers for water-in-oil emulsions to reduce sludge formation in lubricating oil com- United States latent O ice position containing dispersants derived from substituted succinic acid by Murphy in U.S. Pat. 3,509,052.

SUMMARY OF THE INVENTION The hydrocarbon oil lubricating compositions of this invention contain a minor amount of an ashless detergent which is a hydrocarbyl substituted amine or polyamine wherein said hydrocarbyl substituent contains at least 40 carbon atoms, sufiicient alkaline earth metal carbonate dispersed in the hydrocarbon oil to provide an alkalinity value of from 0.5 to mg. KOH/g, and preferably dispersed by a sulfonate derived from sulfonic acid of from 25 to 50 carbon atoms or a phenate derived from alkylated phenol or polymerized alkylated phenols having 2-5 phenol groups per molecule and an alkyl group of from 12-30 carbon atoms, and as a critical third additive enhancing the rust inhibitory capacity of the composition, a small percentage of certain oxaalkane derivatives, i.e., a polyoxyalkylene chain capped by certain polar functional groups, and preferably a polyoxyalkylene polyol or glycol, of molecular weight in. the range from about 1,000 to about 20,000.

DESCRIPTION OF THE INVENTION The present invention relates to the art of lubricating oil formulations for use in internal combustion engines. Such formulations contain a variety of additives which perform specific and overlapping functions in the protection of the inner metallic surfaces of the engine. Antagonistic interaction between such additives is evidenced by degradation of some specific lubricating oil function when both additives are present. It has been found that the presence of basic nitrogenous ashless deter gents serves to degrade the corrosion and rust inhibitory capacity of the composition which is an important function performed by dispersed alkaline earth metal carbonate. It was found by way of a novel solution to this problem that certain oxaalkane derivatives are capable of preventing the antagonistic degradation of antirust performance when the usual percentage of hydrocarbyl substituted amine or polyamine detergent is also present, and even serve to enhance the antirust performance of the oil under these circumstances. These oxaalkanes are termed auxiliary rust inhibitors. Quite surprisingly, the oxaalkane derivative performs this function when present in the hydrocarbon phase to the surprisingly small extent of 0.0l-5 Weight percent. [The application of the oxa nomenclature to cyclic systems is well established. Long aliphatic chains containing oxygen-atom interrupters are also conveniently named by this method. The oxa names are derived from the name of the corresponding aliphatic hydrocarbon by prefixing 07m to it. In the usage of this discussion oxa denotes long-chained aliphatic compounds containing oxygenatom interrupters] For reasons of solubility, reactivity and ease of preparation, stability and lack of degradation under engine conditions, and effectiveness as auxiliary rust inhibitors, the preferred oxaalkane derivatives are urethanes and esters of polyoxyalkylene polyols, especially acetates, sebacates, oXalates and succinates, and most preferably, polyoxyalkylene polyols and glycols of molecular weight in the range from 1,000 to 20,000, and especially those of high molecular weight.

Polyoxyalkylene derivatives Derivatives of polyoxyalkylene compounds which are useful to a certain extent as auxiliary rust inhibitors and acid neutralization accelerators when used in combination with dispersed alkaline earth metal carbonates include certain oxaalkane chains capped with polar functional groups such as carboxy, carbonyl, carboxylate, amino, amido, thio, and phosphoro groups, for example, Lowe, US. Pat. 3,037,056 and US. Pat. 2,879,230.

Auxiliary rust inhibitors which are derivatives of the polyoxyalkylene polyols are produced by reacting the polyol with organic monoand polyisocyanates; or monoand polycarboxylic acids, or acid halides and anhydrides, to yield high molecular weight complex reaction products which may be typified as complex polyesters or urethanes. The polycarboxylic acids which can be utilized by reaction with polyoxyalkylene polyols and glycols include, for example oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacid and other oc,wdiCalbOX- ylic acids and alkyl or alkenyl substituted acids of the same name. Of these, the alkenyl succinates and sebacates of polyoxyalkylene polyols are preferred, and the sebacates are most preferred.

The organic isocyanates which can be utilized by reaction with polyoxyalkylene polyols include, for example, phenyl isocyanate, toluene diisocyanate, methylene diphenyl diisocyanate, alkylated methylene diphenyl diisocyanate, hexamethylene diisocyanate, and polymeric isocyanates, such as polymethylene, and polyphenyl isocyanate. The urethanes are preferred derivatives of polyoxyalkylene polyols for ease of reactivity.

As stated elsewhere, the particularly preferred auxiliary rust inhibitors which serve in small percentages as a third additive in compositions containing hydrocarbyl substituted amine detergents and dispersed alkaline earth metal carbonate to enhance the rust and corrosion inhibitory capacity of the oil, are the polyoxyalkylene polyols and glycols which consist essentially of a certain oxaalkane chain capped by hydroxyl groups. The glycols are preferably of the general formula wherein R and R are ethylene or propylene radicals, a is in the range from to [2/5, b is in the range from to 200, and c is in the range from 0 to 11/5, such that the total molecular weight of the polyoxyalkylene glycol is in excess of 1,000.

Some of the lower molecular weight polyoxyalkylene glycols within this range are commercially available from Wyandotte Chemicals Corporation as the Pluronic series. The preferred polyoxyalkylene glycols of the general formula shown are propylene oxide polymers or block copolymers prepared, for example, by adding propylene oxide to the two hydroxy groups of a propylene glycol nucleus. The resulting hydrophobic base can be made to any control length varying from 800 to thousands in molecular weight. By adding ethylene oxide to both ends of this hydrophobic base, it is possible to put polyoxyethylene hydrophilic groups on both ends of the molecule. The hydrophilic groups may be added to constitute anywhere from a few percent to 80 percent of the final molecule (US Pat. 2,674,619). In general, the polyoxyalkylene glycols are mixtures of compounds that differ slightly in polymer chain length. However, their properties approximate those of the molecule represented by their average composition. Solubility in lubricating oils shows that the most effective compounds of this form for our purpose contain substantially less than 20 percent polyoxyethylene units by weight.

Polyoxyalkylene polyols within the scope of the present invention can be made by adding propylene oxide, or ethylene oxide, or both, to polyols, such as pentaerythritol, dipentaerythritol, tripentaerythritol, trimethanol propane, etc. The polyoxyalkylene polyols are also useful when modified by formation of urethanes, esters, ether capping, etc., as described elsewhere herein.

Amines The nitrogenous ashless detergents of this invention are high molecular weight branched-chain aliphatic hydrocarbyl N-substituted amines which are superior detergents in both lubricating oils and hydrocarbonaceous fuels for internal combustion engines. These detergents have average molecular weights in the range of about 500 to 10,000 and more usually in the range of about 750 to 5,000. For the most part, the detergents of this invention will have the following formula:

Cfizh bl y The above symbols are defined as follows:

A=hydrogen, hydrocarbyl of from 1 to 10 carbon atoms, and hydroxy hydrocarbyl of from 1 to 10 carbon atoms.

X=hydrogen, hydrocarbyl of from 1 to 10 carbon atoms, hydroxy hydrocarbyl of from 1 to 10 carbon atoms, and may be taken together with A to form a ring of from 5 to 6 annular members with up to 12 carbon atoms.

U=alkylene of from 2 to 6 carbon atoms, there being at least 2 carbon atoms, between the nitrogen atoms.

R=an aliphatic hydrocarbyl radical of from about 400 to 5,000 average molecular weight.

a =an integer of from 0 to 10.

b =an integer of from 0 to 1.

a +2b =an integer of from 1 to 10.

c =an integer of from 1 to 5 and is an average in the range of 1 to 4, and equal to or less than the number of nitrogen atoms in the molecule.

x=an intger of from 0 to 1.

y=an integer of from 0 to l.

x+y=equal to 1.

The hydrocarbyl radical indicated by R is relatively free of aliphatic unsaturation; that is, it will usually have not more than two sites of olefinic unsaturation and generally not more than one site of olefinic unsaturation and no acetylenic unsaturation.

The aliphatic hydrocarbyl radical will ordinarily be prepared by polymerizing olefins of from 2 to 6 carbon atoms (ethylene being copolymerized with another olefin so as to provide a branched chain). The branched chain hydrocarbyl radical will generally have at least one branch per 6 carbon atoms along the chain, preferably at least one branch per 4 carbon atoms along the chain, and particularly preferred that there be at least one branch per 2 carbon atoms along the chain. That is, the preferred branched chain hydrocarbon radicals are polypropylene and polyisobutylene. The branches will usually be of from 1 to 2 carbon atoms, preferably 1 carbon atom, i.e., methyl.

In most instances, the compositions of this invention are not a pure single compound, but rather a mixture of compounds having an average molecular weight. Usually, the range of molecular weights will be relatively narrow and peak near the indicated molecular Weight. Similarly, for the more complicated polyamines, the compositions will be a mixture of amines having as the major product the compound indicated as the average composition and having minor amounts of analogous compounds relatively close in composition to the dominant compound.

The indicated general formula includes monoamines exemplified by polypropenyl amine, polyisobutenyl amine, N-polyisobutenyl dimethyl amine, N-polyisobutenyl methylethyl amine, n-polypropenyl diethyl amine, N-polypropenyl di(2-hydroxyethyl)amine, N-polyisobutenyl-N- methyl aniline, N-polyisobutenyl morpholine, N-polyisobutenyl piperidine, Npoly(l-butene)propylamine, N- polypropenyl-N-(Z-hydroxyethyDamine, etc. Also encompassed within the scope of the ashless detergents of the present invention are polyamines such as N-polyisobutenyl ethylene diamine, n-polypropenyl ethylene diamine, N-poly(1-butenyl)ethylene diamine, N-(alternating copolymer of ethylene and isobutenylene)ethylene diamine (alternating copolymers of ethylene and isobutylene may be achieved by cationic polymerization of 4- methyl pentene-l), N-polypropenyl-Z-aminoethyl piperazine, N-polyisobutenyl-2-aminoethy1 piperazine, N-polypropenyl diethylene triamine, N-polyisobutenyl diethylene 'triamine, N-poly(1-pentenyl)diethylene triamine, N-polypropenyl trimethylene diamine, N-polyisobutenyl trimethylene diamine, N-polypropenyl di(trimethylene)triamine, N-polyisobutenyl di(trimethylene)triamine, N polyisobutenyl-1,2-propylene diamine, N-polyisobutenyl di(1,2 propylene)triamine, N-polyisobutenyl tetraethylene pentamine, N-polyisobutenyl pentaethylene hexamine, N- polyisobutenyl triethylene tetramine, etc.

Polyhydrocarbyl radical substituted alkylene polyamine compositions also fall within the scope of the ashless detergents of the present invention and they include such compounds as, for example, N,N-di(polypropenyl)diethylene triamine, N,N-di(polyisobutenyl)diethylene triamine, N,N-di(polyisobutenyl)triethylene tetramine, N, N di(polypropenyl)tetraethylene pentamine, N,N-di (polyisobutenyl)tetraethylene pentamine, etc.

Commonly available alkylene polyamines are the ethylene polyamines having from 2 to 6 amino nitrogen groups. When these are substituted with a branched-chain aliphatic hydrocarbon group, these compositions will have the following formula:

a is an integer of from 1 to 5, more usually from 1 to 4;

The method of preparation and further details on the hydrocarbyl substituted amine ashless detergents of the present invention can be found in U.S. Pats. 3,565,804, 3,574,576, and 3,438,757, the disclosures of which are incorporated herein by reference.

Alkaline earth metal carbonates The alkaline earth metal carbonates are magnesium, calcium and barium carbonates, preferably calcium and barium carbonates. Small amounts of the hydroxide of the metals may also be present, usually not contributing more than about 20 percent of the alkalinity value from the alkaline earth metal carbonate composition. The alkaline earth metal carbonates are not soluble in hydrocarbon media, therefore, they are invariably dispersed with some type of metal salt dispersant. These dispersants are well known in the art and will be discussed only summarily.

The preferred alkaline earth metal carbonate dispersants are the sulfonates and phenates. The sulfonates are extensively discussed in U.S. Pat. 3,488,284. The organic sulfonates are prepared from either natural or synthetic sources. The natural sulfonates are referred to as mahogany sulfonates and are derived from petroleum mineral fractions and normally have from about 25 to 50 carbon atoms per sulfonic acid. Synthetic sources are also employed which are usually alkylated benzenes having from about 25 to 50 carbon atoms. The use of the sulfonates and the method of preparing overbased sulfonates is well known as indicated in the above patent. Other patents include U.S. Pats. Nos. 3,021,280, 3,256,- 186, 3,057,896, and 3,312,618. The disclosures of these patents and U.S. 3,488,284 are incorporated herein.

Another class of dispersant for alkaline earth metal carbonates are the phenates. The phenates are alkylated phenols either individually or polymerized to a low order of from 2 to 5 alkyl phenols, normally bridged with sulfur, alkylene groups, or di(alkylene)amino groups (Mannich bases). The alkyl group on the phenol is normally of at least 8 carbon atoms and usually does not exceed 36 carbon atoms, more usually being in the range of about 12 to 30 carbon atoms. The phenoxide in the:

phenate also contributes to the alkalinity value. The overbased phenates are described in numerous patents such as U.S. Pats. Nos. 3,474,035, 3,429,812, 3,388,063, 3,336,- 224, and 2,798,852, and disclosures of which are incorporated herein.

The alkalinity value of the overbased dispersant will usually be at least 150 and not exceed 500, more usually being in the range of about 200 toabout 450 mg. KOH/ g. The equivalent ratio of base to dispersant will be at least 1:1 and more usually 1.5: 1, normally not exceeding about 20:1.

These compositions are used in a sufficient amount to provide the desired alkalinity value in the final composition. Therefore, the alkaline earth metal carbonates are prepared as concentrates and then diluted into a lubricating oil medium with the hydrocarbyl substituted amines and polyoxyalkylene derivatives to provide the desired end composition.

Lubricating oils The oils which find use in this invention are oils of lubricating viscosity derived from petroleum or synthetic sources. The oils may be paraffinic, ester, naphthenic, halo-substituted hydrocarbons, asphal'tic or combinations thereof. Oils of lubricating viscosity normally have viscosities in the range of 35 to 50,000 Saybolt Universal seconds (SUS) at F., more usually from about 50 to 10,000 SUS at 100 F.

Other additives Other additives are desirably included in the composition. These additives may be pour point depressants, oiliness agents, antioxidants, detergents, corrosion inhibitors, extreme pressure agents, etc. Usually, for oils to be used in an internal combustion engine, the total amount of these additives will range from about 0.1 to 15 weight percent, more usually from about 0.5 to 10 weight percent. The individual additives may vary in amounts from about 0.01 to 10 weight percent of the total composition. In concentrates, the weight percent of these additives will usually range from about 0.3 to 30 weight percent. A preferred aspect of using the compositions of this invention is to include in the oil from about 1 to about 50 mM./kg. of a dihydrocarbyl phosphordithioate, wherein the hydrocarbyl groups are from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl groups. The remaining valence of the phosphorodithioate will usually be satisfied by zinc, but polyalkleneoxy, or a third hydrocarbyl group may also be used. (As used throughout this specification, hydrocarbyl is an organic radical composed solely of carbon and hydrogen which may be aliphatic, alicyclic or aromatic unless specified to the contrary.)

The ultimate determinants of the eifectiveness of lubricating oil compositions of the present invention are the MS Sequence IIB and HG engine tests. The IIB test is part of the GM specification and requires an average engine rust rating (AER) of 8.9 to pass.

Example 1 A lubricating oil composition containing 4.4 percent by weight of a polyisobutenyl substituted ethylene diamine wherein the average molecular weight of the polyisobutenyl is 1,400, 25 mM./kg. of a calcium carbonate dis persed by sulfonate composition containing 2.35 percent calcium, 40 mM./kg. of a calcium carbonate dispersed by polypropylene phenate composition containing 9.25 percent calcium and 15 mm./kg. of zinc bis(polypropenyl phenol)dithiophosphate, in a neutral hydrocarbon oil having a viscosity of 30 SUS at 100 F. This composition gave average engine rust ratings in MS Sequence IIB engine tests of 7.9 and 7.1.

Example 2 The lubricating oil composition of Example 1, containing in addition, 0.1 percent by weight of a polyoxyalkylene glycol block copolymer of oxypropylene and oxyethylene units having, typically, percent by Weight of polyoxyethylene, and 90 percent by weight of polyoxypropylene, and average molecular weight of 4,440. This composition gave an average engine rust rating in the MS Sequence IIB engine test of 9.0.

Example 3 A lubricating oil composition containing 2.7 percent by weight of a polyisobutenyl substituted ethylene diamine wherein the average molecular weight of the polyisobutenyl is 1,400, 5 mM./kg. of calcium sulfonate (1.67% Ca), 60 mM./kg. carbonated calcium polypropylene phenate containing dispersed calcium carbonate (9.25% calcium), 6 mM./kg. zinc bis(polypropenyl phenyl)-dithiophosphate, 9 mM./-kg. zinc dialkyl dithiophosphate, and 0.1 Weight percent of polyalkylmethacrylate in a neutral petroleum oil of viscosity 30 SUS at 1040 F. This composition gave an average engine rust rating in the MS Sequence IIC, which is more severe than the IIB, of 7.2.

Example 4 The lubricating oil composition of Example 3, containing in addition, 0.1 percent by Weight of the polyoxyalkylene glycol described in Example 2. This composition gave an average engine rust rating of 8.9 in the severe IIC engine test.

Example 5 The lubricating oil composition of Example 3, containing in addition, 0.1 percent by weight of the reaction product of the polyoxyalkylene glycol of Example 2 with oxalic acid in the mole ratio of 1: 1.

Example 6 The lubricating oil composition of Example 1 with the addition of 0.05 or more weight percent of the reaction product of the polyoxyalkylene glycol of Example 2 with toluene diisocyanate in a mole ratio of approximately 1:1.

Example 7 The lubricating oil composition of Example 3, containing in addition, 0.1 percent by weight of the reaction product of the polyoxyalkylene glycol of Example 2 with sebacic acid in the mole ratio of 1: 1.

Example 8 The lubricating oil composition of Example 3, containing in addition, 0.1 percent by weight of the reaction product of the polyoxyalkylene glycol of Example 2 with tetrapropenyl succinic acid in the mole ratio of 1:1.82.

Example 9 The lubricating oil composition of Example 3, containing in addition, 0.1 percent by weight of the reaction product of the polyoxyalkylene glycol of Example 2 with the polyoxypropylene polyol formed by the addition of propylene oxide to tripentaerythritol.

As is typical in formulations (Examples 1 and 3) containing both a basic nitrogenous ashless detergent (polybutene amine) and dispersed alkaline earth metal carbonate the average engine rust ratings are quite poor 7.17.8. It is surprising to find that 0.1 weight percent of polyoxyalkylene glycol serves to enhance the antirust performance of the oil to such a degree that the average engine rust ratings are pulled up to 8.99.0.

What is claimed is:

1. A lubricating oil composition comprising a major amount of an oil of lubricating viscosity, a minor amount of a hydrocarbyl substituted amine wherein the hydrocarbyl substituent contains at least 40 carbon atoms, 0.01 to 5 percent by weight of a polyoxyalkylene polyol, glycol, ester, or urethane characterized by an average molecular weight in the range from about 1,000 to about 20,000, and sufficient alkaline earth metal carbonate dispersed in said oil to provide an alkalinity value of from 0.5 to mg. KOH/g.

2. A lubricating oil composition according to claim 1 wherein the polyoxyalkylene glycol is a polyoxyalkylene glycol block copolymer of the general formula:

CH: b

wherein R and R are ethylene or propylene radicals, a is in the range from 0 to b/S,

b is in the range of from 10 to 200, and

c is in the range from 0 to 12/5.

3. A lubricating oil composition according to claim 1 wherein the hydrocarbyl substituted amine is of the general formula:

the above symbols are defined as follows:

A=hydrogen, hydrocarbyl of from 1 to 10 carbon atoms, and hydroxyl hydrocarbyl of from 1 to 10 carbon atoms;

X hydrogen, hydrocarbyl of from 1 to 10 carbon atoms, hydroxyl hydrocarbyl of from 1 to 10 carbon atoms, and may be taken together with A to form a ring of from 5 to 6 annular members with up to 12 carbon atoms;

U=alkylene of from 2 to 6 carbon atoms, there being at least 2 carbon atoms between the nitrogen atoms;

R=an aliphatic hydrocarbyl radical of from about 400 to 5,000 average molecular weight;

a =an integer of from 0 to 10;

b =an integer of from 0 to 1;

a +2b =an integer of from 1 to 10;

c =an integer of from 1 to 5 and is on average in the range of 1 to 4, and equal to or less than the number of nitrogen atoms in the molecule;

x=an integer of from 0 to 1;

y=an integer of from 0 to 1; and

x+y=equal to 1.

4. A lubricating oil composition according to claim 1 wherein the hydrocarbyl substituted amine is of the general formula 3 Z n c 3+a -cl wherein:

a is an integer of from 1 to 5, more usually from c is an integer or fractional number of from 1 to 4, more usually of from 1 to 3 and preferably being in the range of about 1 to 2; and

R is a branched-chain aliphatic hydrocarbon group derived from polymerizable olefins of from 3 to 4 carbon atoms and having a molecular weight in the range of about 650 to 2,800 and preferably 750 to 2,000.

5. A lubricating oil composition according to claim 1, wherein said hydrocarbyl substituted amine is chosen from the group consisting of polyisobutenyl ethylene diamine, polyisobutenyl diethylene triamine, polyisobutenyl triethylene tetramine, and polyisobutenyl tetraethylene pentamine, the polyamine having in each case from 1 to- 3 9 polyisobutenyl groups of from about 600 to about 2,800 average molecular weight.

6. A lubricating oil composition according to claim 1, wherein said hydrocarbyl substituted amine is selected from the group consisting of polypropenyl ethylene diamine, polypropenyl diethylene triamine, polypropenyl triethylene tetramine and polypropenyl tetraethylene pentamine, said polyamine having in each case from 1 to 3 polypropenyl groups of from about 650 to 2,800 average molecular weight.

7. A lubricating oil composition according to claim 1, wherein the polyoxyalkylene ester is an ester of a polyoxyalkylene glycol having a molecular weight in the range from about 1,000 to 20,000 and a monoor dicarboxylic acid.

8. A lubricating oil composition according to claim 1, wherein the polyoxyalkylene glycol is capped by an alkyl ether of from 1 to 20 carbon atoms.

9. A lubricating oil composition according to claim 1,

wherein the polyoxyalkylene urethane is a urethane or polyurethane of an aliphatic or aromatic monoor polyisocyanate.

References Cited UNITED STATES PATENTS 3,189,543 6/1965 Criddle 252-25 3,390,562 7/1968 Rausch et. al. 252-25 3,186,944 6/1965 Dreher 252-25 3,464,925 9/1969 Denoit et a1 252-515 R 3,456,013 7/1969 Egan et all 252-515 R 3,062,743 11/1962 Manteufiel et al. 252-51.5.R 3,574,576 4/1971 Honnen et al. 252-50 3,565,804 2/1971 Honnen et a1. 252-50 WERTEN F. W. BELLAMY, Primary Examiner US. Cl. 252-25, 49