GB1579659A

GB1579659A - Oil-soluble products of an oxidised ethylene-olefin copolymer and an anionically polymerizable monomer having utility as multifunctional vi for lubricating oil

Info

Publication number: GB1579659A
Application number: GB13861/77A
Authority: GB
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1976-04-26
Filing date: 1977-04-01
Publication date: 1980-11-19
Also published as: JPS52130890A; CA1089588A; FR2355858A2; FR2355858B2; IT1113560B; DE2718248A1

Description

(54) OIL-SOLUBLE PRODUCTS OF AN OXIDISED ETHYLENE-OLEFIN COPOLYMER AND AN ANIONICALLY POLYMERIZABLE MONOMER HAVING UTILITY AS MULTI-FUNCTIONAL V.I. IMPROVERS FOR LUBRICATING OIL (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to nitrogen-containing viscosity-index improving polymeric additives which also improve sludge dispersancy, pour point depressancy and oxidative stability of oleaginous compositions, to the resulting oil compositions and to the preparation of said additives. Broadly, the novel additives are nitrile-containing copolymers prepared by a condensation reaction of reactants, such as acrylonitrile, onto oxidized ethylene/alpha-olefin copolymers induced by a thermal means or in the presence of a strong base catalyst, such as sodium hydroxide.

The preparation of multifunctional V.I. improving polymeric substances according to the prior art included copolymerization of one or more olefins with a nitrile-containing monomer (U.S. 3,445,387); free radical-grafting a hydroperoxidized ethylene copolymer with a polar vinylidene monomer, such as acrylonitrile (see U.S. 3,404,091); reacting a nitrile-containing compound with a reactive copolymer such as is obtained from free radical-grafting of maleic anhydride to polyisobutylene (see U.S. 3,448,049); free radical-grafting an ester of an amino alcohol onto an oxidized interpolymer of ethylene and propylene (see U.S. 3,687,849); and thermally reacting amines with an oxidized ethylene-propylene copolymer (see U.S. 3,864,268).

These processes which utilize free radicals have certain disadvantages, including irreversible crosslinking of the copolymer and homopolymerization of monomeric components. One of such disadvantages is shown in U.S. Patent No. 3,236,917 wherein the initiation of the desired addition reaction by the generation of free radicals also provokes grafting of a single molecule of maleic anhydride onto two copolymer chains thereby irreversibly crosslinking the copolymer and markedly decreasing its solubility in oil. One approach to overcoming this disadvantage is shown in U.S. Patent 3,378,492 which teaches grafting an unsaturated hydrocarbon polymeric compound, e.g. polybutadiene, directly with an unsaturated, polar, nitrogen-containing organic compound, e.g. acrylonitrile, by a free radical initiated reaction.

Another approach to preparing an oil-soluble nitrogeneous ashless dispersant involves reacting an alkali metal salt of a long-chain ketone with acrylonitrile (see U.S. 3,565,803 and 3,723,501). Unfortunately, formation of the dialkyl ketone precursor is by ozonization which is an expensive and hazardous process involving dimethyl sulfide, an environmental toxic agent.

Also taught as a multifunctional additive for lubricating oils is the anionic-graft polymer of a lithiated ethylene-propylene-hexadiene terpolymer with an amino methacrylate monomer (see U.S. 3,879,304).

The present invention therefore provides an oil soluble addition product having a number average molecular weight in the range of 1,000 to 500,000 while containing the range of 0.005 to 10 wt.% nitrogen, said oil soluble addition product being a condensation reaction product of: (1) an anionically polymerizable monomer containing in the range of 3 to 50 carbon atoms and at least one electron withdrawing group in such proximity to a double bond that said bond is activated, said monomer being selected from the group consisting of: (a) N,N (di C1-lo hydrocarbyl) carbodimides: (b) monomers of the formula:

wherein X is oxygen or an NR" group; n is 2 to 5; R' and R" are hydrogen or a C1 to C4 alkyl group; and R" and R"" are C1 to C12 hydrocarbyl groups and (c) nitrile monomers of the formulae:

wherein RV is hydrogen or lower alkyl and X is selected from the group consisting of hydrogen, halogen, cyano and lower alkyl; and (2) an oxidized ethylene copolymer comprising 20 to 80 mole % ethylene and 20 to 80 mole % of a C3 to Co mono-alpha-olefin having an oxygen content of from 0.005 to 6 wt % said reaction product being formed by reacting said monomer and copolymer either thermally in the absence of a catalyst at a temperature in the range 100" to 200"C, or at a temperature in the range 0 C to 200"C in the presence of an aqueous solution of strong base having a pH of at least 8 as sole catalyst.

In addition the invention provides lubricating oils containing such oil soluble addition products and a process for their manufacture.

While the oxidised copolymers are preferably derived from essentially ethylene and propylene, such copolymers may also contain minor amounts, i.e. up to 20 mole percent, preferably about 1 to about 7 mole percent, based on the molar amounts of the monomeric ethylene and propylene units in the copolymer, of polymerized units derived from other olefin monomers. Such other olefin monomers include olefins of the general formula RCH=CH2, in which R is an aliphatic or cycloaliphatic radical of from 2 to about 48 carbon atoms, for example, 1 -butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-decene, 5 ,5-dimethyl-1-pentene, 5-methyl-1-hexene, 5-methyl-1-heptene, 6-methyl-1heptene and 5,6,6-trimethyl-1-heptene. Such other olefins also include monomers having a plurality of double bonds, in particular diolefins containing from 4 to 26 carbon atoms, e.g.

1,3-butadiene, 1 4-pentadiene, 2-methyl-1,5-hexadiene, 1,7-octadiene, and preferably non-conjugated diolefins such as vinylidene norbornene, 5-methylene-2-norbornene and 1,4-hexadiene.

Suitable copolymers have a degree of crystallinity of less than 25 weight percent as determined by X-ray and differential scanning calorimetry and preferably they contain 35 to 65 mol % ethylene and from 35 to 65 mole percent propylene. The polymers have a number average molecular weight (Mn) of from 1000 to 500,000, preferably 10,000 to 200,000, optimally from 20,000 to 100,000.

In accordance with this invention, these copolymers which as indicated include terpolymers, for example, a terpolymer of ethylene, propylene and a non-conjugated diene such as 2-ethylidene-5-norbornene, 5-ethylidene-2-norbornene or 1,4-hexadiene, can be condensed according to the invention provided the terpolymer is suitably oxidized whereby sites for the catalyzed addition are created.

The oxidation can be accomplished by contacting the copolymer under suitable conditions of temperature and at atmospheric or elevated pressures with an oxidizing agent, such as air or free oxygen, or any oxygen-containing material capable of releasing oxygen under the oxidation conditions. If desired, the oxidation can be conducted in the presence of known oxidation catalysts such as platinum or a platinum group metal, and compounds containing metals such as copper, iron, cobalt, cadmium, managanese, and vanadium.

Generally, the oxidation can be carried out over a wide temperature range depending upon the activity of the agent used. For example, with air, temperatures in the range of 35-425"C. have been used. Further, depending upon the rate desired, the oxidation can be conducted at sub-atmospheric, atmospheric or super-atmospheric pressures.

Oxidation of the copolymers and terpolymers dissolved in a solvent, such as mineral oil, is conveniently carried out, either in batches or continuously, in a stirred reactor with air, or air prediluted with an inert gas, such as nitrogen or carbon dioxide, so as to minimize explosion hazards. The air, or diluted air, may be introduced into the oil-polymer solution in a finely divided state, fritted glass thimbles, or similar means possessing a foraminiferouslike structure, at a temperature in the range of 80"C. to 3000C., preferably 100"C. to 2300C.

Rapid agitation of the reactor contents, as for example, by means of a turbomixer, is desirable in large batches, to ensure an optimum reaction rate and a low oxygen content in the off-gas.

In general, in the range of 0.5 to 90, e.g., 4 to 60 weight percent of the oil copolymer solution will be copolymer. Usually, about 20 to 60 weight percent of the solution will be copolymer when the polymer is of low mol. wt., erg., with a number average molecular weight (Mn) less than 20,000. For copolymers with Mn equal to or greater than 20,000, the preferred concentrations are in the range of 4 to 20 weight percent copolymer, based on the total weight of the oil-copolymer solution.

A wide variety of mineral lubricating oils which widely range in viscosity and crude source, may be used as solvents for the polymer-oil solutions to be oxidized. They may range in viscosity from 5 to 1000 SUS &commat;100 F., preferably 10 to 600 SUS &commat;1000F., most preferably 80 to 200 SUS &commat;380C. They may be straight-run distillates in the lubricant range, e.g., boiling above 315"C., or may have been further refined.

Oxidation of the oil-copolymer solution is conducted for a time sufficient to impart to the solution a combined oxygen content of 0.01 to 10.0, e.g., 0.1 to 8, preferably 0.1 to 5.0 weight percent, depending on the composition of the oil, the copolymer and the concentration of copolymer in solution.

A measure of the degree of oxidation is the specific infrared absorption exhibited by oxygen containing group functionality at about 5.8 microns. Oxygen group functionality may conveniently be measured with an infrared spectrometer using 0.05 mm to 0.5 mm specimen thickness and sodium chloride cells.

As used herein, such terms as "oxidized", or "oxidized oil copolymer solution " indicates that air or oxygen containing gas is used for the oxidation, and precludes the use of other oxidative reagents such as ozone.

Alternatively the copolymer can be oxidized in the absence of a solvent as by oxidative degradation of the copolymer. This oxidation approach is well known in the art (see Published French Application No. 75.23806) whereby oxygen is incorporated into the copolymer by an air-mastication procedure. This procedure may be done with a single piece of equipment or in stages. Useful equipment includes Banbury mixers and mills wherein the copolymer is readily exposed to air, which devices may be enclosed in jacketed containers through which a heating medium may be passed. When oxidation resulting from the air-mastication has reached a desired level i.e. at least 0.005 weight percent oxygen as determined by oxygen uptake in said copolymer, mineral oil may be added to provide a concentration of the oxidized copolymer in the range of 5 weight percent to 50 weight percent, based on the weight of the total resulting solution.

Where oxidation is provided by air-mastication the copolymer is limited to ethylene and one or more alphamonoolefins having from 3 to 50 carbons and preferably propylene to avoid deleterious crosslinking during oxidation.

N ,N-diisopropylcarbodiimide, N ,N-dimethylcarbodiimide, and N ,N ' -methylethylcarbodiimide (are representative of a highly useful and preferred class of N,N(di Cl~lO) hydrocarbyl carbodiimides.

A preferred class of nitrogen-containing reactants for use in the present invention have the formula:

wherein X is oxygen or an NR" group, n is a whole number from 2 to 5, R' and R" may be the same or different and are individually selected from the class consisting of hydrogen and a C1 to C4 alkyl group, R"' and R"" are each C1 to C12, preferably C1 to C4, hydrocarbyl groups, e.g. alkyl groups. Amino methacrylates, such as dialkylaminoethylmethacrylates, are particularly useful.

Specific examples of compounds encompassed within the preferred class of nitrogencontaining condensation reactants include dimethylaminoethyl methacrylate, diethylaminopropyl methacrylate, diethylaminopropyl methacrylamide, di(isobutyl) aminoethyl methacrylate, methylisobutylaminopropyl acrylate. Mixtures of various nitrogen containing monomers may be reacted as well as the individual monomers with the oxidized ethylene copolymers.

The most preferred nitrogen-containing reactants for use in the present invention have the formula:

where RV is a hydrogen atom or a lower alkyl, e.g., methyl, ethyl, X is a hydrogen atom, a halogen atom, a cyano or a lower alkyl group, e.g. methyl, ethyl, propyl, butyl. The term "lower alkyl" refers to the C1 to C6 range. Examples of nitrile monomers which are contemplated by the aforedescribed structure include acrylonitrile, methacrylonitrile, allyl cyanide. When said condensation reactant is acrylonitrile, said reaction is extremely facile so that acrylonitrile represents an optimal reactant.

It has been indicated that aciylonitrile is readily condensed with an oxidized copolymer in a base catalyzed addition reaction to provide a polymeric addition product according to the invention. Such a condensation could be classified as a cyanoethylation reaction. Further, it has been discovered that the reactions of the invention in their preferred form are similar in many respects to a Michael condensation reaction (see A. Michael, J. Prakt. Chem. [2] 35, 349 (1887)) which is further described in The Merck Index, Eighth Edition (1968), page 1193 under Michael Condensation (Michael Addition).

Usually the condensation reaction is carried out in an inert solvent. These solvents may be polar or non-polar. Illustrative hydrocarbon solvents include benzene, toluene, cumene and preferably hydrocarbons of from 6 to 10 carbon atoms such as hexane, cyclohexane and heptane. Other solvents include ethers, both aliphatic and aromatic, such as diethyl ether and dimethyl ether with tetrahydrofuran being preferred. Individual solvents or mixtures may be used. A highly useful solvent is mineral oil or mixtures thereof in which the oxidized copolymer is generally prepared.

The condensation reactant may be added either batchwise or incrementally to the oxidized ethylene-propylene solution. Preferably, the reactant is added incrementally with vigorous stirring so as to obtain relatively homogeneous diffusion of the condensation reactant into the reaction mixture.

The preparation of the functionalized polymer from the oxidized copolymer is theorized to occur by inducing abstraction of the acidic proton located alpha to a carbonyl structure present in the oxidized copolymer. This inducing can be achieved either by physical means such as heat or catalytic means such as by the presence of a stronge base, e.g. sodium hydroxide. Oxidation of the ethylene copolymer is believed to introduce a multiplicity of complex carbonyl structures, such as keto-, aldo, or acido-, into the backbone of the polymeric molecules. Preparation of the addition product of the oxidized copolymer does not measurably alter these carbonyl structures since the condensation reactant is added onto said copolymer backbone by means of an induced condensation reaction.

The condensation reaction comprises contacting said substantially linear oxidized copolymer in a solvent with a catalytic amount of a strong aqueous base, most usually a strong inorganic base, preferably sodium hydroxide, and an anionically polymerizable monomer, preferably acrylonitrile. For purposes of this disclosure a strong base has a pH of at least 8, preferably at least 11. A temperature of between 0 C. to 2000C. and time of 0.2 to 25 hours is used.

Alternatively the condensation reaction can be effected at elevated temperature. In accordance with this method, said oxidized copolymer is thermally contacted with said condensation reactant, preferably acrylonitrile. Usually, the reaction is carried out in an inert solvent such as mineral oil. In accordance with this procedure temperatures in the range of 100"C. to 2000C., preferably 140"C. to 1500C. and periods of between 1 and 25 hours, preferably 3-7 hours are generally useful.

The base catalyzed condensation reaction of the copolymer and the condensation reactant as noted is generally carried out in the range of between 0 and 100"C. and with agitation at atmospheric pressure or under super-atmospheric pressure up to as high as 2000 psi. The overall time of reaction varies between 0.2 and 25 hours, preferably between 0.5 and 10 hours. The base condensation catalyst is as noted any strong base, e.g. a strong organic base such as triethylamine, a strong aqueous base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, and alkoxides such as sodium ethoxide which provide a pH of at least 8.

The proportions in which the above-described nitrogen-containing reactants are to be used may range widely according to the ability of said oxidized copolymer and said nitrogen-containing reactant to react with each other, but normally should range from 0.1 to 400, preferably 10 to 200 parts by weight of said monomer to 100 parts by weight of said oxidized copolymer (said oxidized copolymer containing from 0.005 to 6 weight percent, preferably 0.01 to 3 weight percent, oxygen).

It is generally desired to form oil-soluble polymeric additive products containing 0.005 to 2%, and preferably 0.05 to 0.8% by weight nitrogen (all of said percents by weight nitrogen values in this specification are determined by the Kjeldahl method). Products containing such quantities of nitrogen have sufficient dispersancy sites to impart multifunctionality to said copolymers whereby addition of said products enhances the lubricating performance of lubricating oils.

The polymetic additive products of the catalyzed condensation reaction of the invention broadly will contain from 0.005 percent to 10 percent by weight nitrogen. As the nitrogen content increases above about 0.8 weight percent, the product becomes increasingly less soluble in hydrocarbons such as mineral oil whereby its utility as a hydrocarbon resistant material is increased.

Generally, the number average molecular weights of the additive products of the present invention, employed as lubricant additives, will be in the range of 1000 to 500,000 and preferably will be in the range of 10,000 to 200,000. However, it will be understood that higher or lower molecular weight products may be prepared in accordance with the present invention, if desired. All molecular weight values set forth in this specification are number average molecular weights (Mn) as determined by vapor phase osmometry (VPO) and membrane osmometry.

When the functionalized polymers are employed in lubricating oils, they are added in proportions of 0.1 to 10.0%, preferably 0.5 to 5.0 percent by weight. It is convenient to prepare concentrated oil solutions in which the amount of the polymer in the composition ranges from 10 to 80% by weight, and to transport and store them in such form. In preparing a lubricating oil composition for use as a crankcase lubricant, the polymeric concentrate is merely blended with the base oil in the required amount.

The products of the present invention may be employed not only in ordinary hydrocarbon lubricating oils but also in the "heavy duty" type of lubricating oils which have been compounded with such detergent type additives as metal soaps, metal phenates, metal alcoholates, thiophosphates, amines and amine derivatives, reaction products of metal phenates and sulfur, reaction products of metal phenates and phosphorous sulfides, metal phenol sulfonates.

The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from paraffinic, naphthenic, asphaltic, or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed.

Hydrogenated oils, white oils, or shale oil may be employed as well as synthetic oils, such as synthetic ester oils.

The polymeric additive products have utility as pour depressants for hydrocarbons. This utility includes not only lubricating oil applications but also to improve the cold flow properties of distillate hydrocarbon oils, particularly those fuel oils containing a fraction boiling above 370"C. The polymers of the invention can be used alone or in combination with copolymers of ethylene and vinyl esters of lower fatty acids, such as vinyl acetate. The polymers alone or in combination are added in cold flow improving amounts, i.e. from about 0.001 to 0.5 weight percent based on the weight of the middle distillate.

Example 1 To 10 g. of an oxidized/masticated ethylene-propylene copolymer (containing about 44 weight percent ethylene and about 56 weight percent propylene) of Mn 23,000 in 200 ml. of freshly distilled tetrahydrofuran (THF) maintained at ambient temperature and under a nitrogen atmosphere was rapidly added 1 g. of a 50% NaOH solution. The solution was stirred for 15 minutes while heating to 35"C. To the stirring solution was slowly added over 15 minutes, a solution of acrylonitrile (1 g. 18.5 mmole) in THF (5 ml.). The solution was heated to 40-50"C. for 3 hours, cooled to ambient temperature, then stirred an additional 18 hours.

The condensed polymeric product was recovered by precipitation from a large volume of methanol, then washed with methanol and finally dried in a vacuum oven at about 1()()0C.

for 18 hours, after which 7.6 g. of product was recovered. The polymeric additive product obtained contained 0.085 weight percent nitrogen.

Example 2 Following the procedure of Example 1, 10 g. of an oxidized/masticated ethylenepropylene copolymer (ontaining about 44 weight percent ethylene and about 56 weight percent propylene) of Mn 34,000 was condensed. In this example, however, the solution was heated at 45-600C. for 3 hours. Precipitation yielded 9.6 g. of polymer with a nitrogen content of 0.12 weight percent.

Example 3 Following the procedure of Example 1 with the copolymer of Example 2 upon precipitation yielded 8.4 g. of a polymer with a nitrogen content of 0.065 weight percent.

Example 4 Following the procedure as in Example 1 with the copolymer of Example 2, the solution was heated at reflux; i.e. about 66"C., for 4 hours. Precipitation followed by a second precipitation yielded 9.4 g. of a polymeric additive product with a nitrogen content of 0.09 weight percent.

Example 5 Following the procedure as in Example 4, an oil oxidized/masticated ethylene-propylene copolymer (containing about 44 weight percent ethylene and about 56 weight percent propylene) with an Mn 42,000 (membrane osmometry) was condensed with acrylonitrile.

Precipitation yielded 9.82 g. of a product with a nitrogen content of 0.075 weight percent.

Example 6 Following the general procedure of Example 1,an oil-oxidized/masticated copolymer containing acrylonitrile was prepared by refluxing in THF (about 66"C.) for 5.5 hours.

Precipitation yielded 9.03 g. of product with a nitrogen content of 0.18 weight percent.

Example 7 5 grams of an ethylene-propylene copolymer (containing 46 weight percent ethylene and 54 weight percent propylene) which was air-oxidized from a number average molecular weight of about 72,000 to about 23,000 (membrane osmometry) was dissolved in 45 grams of Solvent 150N mineral oil and placed in a reaction vessel on an electric heater so that the temperature of the reactants could be controlled. 5.0 grams (0.094 moles) of acrylonitrile was introduced into the reaction vessel after which the reaction vessel was flushed with nitrogen and subjected to a pressure of 2 inches of mercury which elevated pressure was maintained during the reaction period. The reaction was carried out by heating the ingredients with agitation at a temperature ranging from 128 to 140"C. for 7 hours. The reaction vessel was cooled to room temperature and the contents subjected to dialysis whereby 4.0 grams of product was obtained which contained 2.25 weight percent nitrogen.

The product exhibited strong absorption at 2270 cm~l by infrared analysis.

Example 8 In this example the efficacy of the polymeric additive products of this invention, particularly with regard to their unusual dispersancy properties in lubricating oil applications, is illustrated by comparison with a commercially available multifunctional V.1.

improver, sold as Lz 3702 by Lubrizol Corporation, in a Sludge Inhibition Bench Test (hereinafter designated SIB). The SIB test has been found, after a large number of evaluations, to be an excellent test for assessing the dispersing power of lubricating oil dispersant additives.

The medium chosen for the SIB test was a used crankcase mineral lubricating oil composition having an original viscosity of about 325 SUS at 38"C. that had been used in a taxicab that was driven generally for short trips only, thereby causing a buildup of a high concentration of sludge precursors. The oil that was used contained only a refined base mineral lubricating oil, a viscosity index improver, a pour point depressant and zinc dialkyldithiophosphate anti-wear additive. The oil contained no sludge dispersant. A quantity of such used oil was acquired by draining and refilling the taxicab crankcase at 1000-2000 mile intervals.

The Sludge Inhibition Bench Test is conducted in the following manner; The aforesaid used crankcase oil which is milky brown in color, is freed of sludge by centrifuging for 1 hour at about 39,000 gravities (gs.). The resulting clear bright red supernatant oil is then decanted from the insoluble sludge particles which thereby separated out. However, the supernatant oil still contains oil-soluble sludge precursors which on heating under the conditions employed by this test will tend to form additional oil-insoluble deposits of sludge. The sludge inhibiting properties of the additives being tested are determined by adding to portions of the supernatant used oil, a small amount, such as 0.5, 1 or 2 weight percent, on an active ingredient basis, of the particular additive being tested. Ten grams of each blend being tested is placed in a stainless steel centrifuge tube and is heated at 138"C.

for 16 hours in the presence of air. Following the heating, the tube containing the oil being tested is cooled and then centrifuged for 30 minutes at about 39,000 gs. Any deposits of new sludge that form in this step are separated from the oil by decanting the supernatant oil and then carefully washing the sludge deposits with 25 ml. of pentane to remove all remaining oil from the sludge. Then the weight of the new solid sludge that has been formed in the test, in milligrams, is determined by drying the residue and weighing it. The results are reported as percent of sludge dispersed by comparison with a blank not containing any additional additive. The less new sludge formed, the larger the value of percent sludge dispersed, and the more effective is the additive as a sludge dispersant. In other words, if the additive is effective, it will hold at least a portion of the new sludge that forms on heating and oxidation stably suspended in the oil so it does not precipitate down during the centrifuging. Using the above-described test, the dispersant action of the several functionalized polymers prepared in accordance with this invention were compared with the dispersing power of a dialyzed product obtained from dialysis of a commercial dispersant previously referred to as Lz 3702. Sufficient dialyzed residue which analyzed about 0.4 weight percent nitrogen, was dissolved in S-150N mineral oil to provide a 10 percent active ingredient concentrate. The dialyzed residue and polymer products of the invention were appropriately diluted in mineral oil to furnish the 0.025, 0.05 and 0.1 weight percent of added additive to the used oil. The test results are given in the Table below.

TABLE Product of Example Concentration gms. Percent Sludge No. Product/10 g.Used Oil Dispersed 1 0.1 77.9 0.05 65.2 0.025 41.4 2 0.1 84.8 0.05 53.6 0.025 29.0 3 0.1 76.8 0.05 32.6 0.025 21.5 4 0.1 90 0.05 60.2 5 0.1 88.0 0.05 65.8 6 0.1 90.7 0.05 65.8 7 0.1 80 0.05 64 0.025 22 Dialyzed LZ 3702 0.1 89 (Commercial Dispersant) 0.05 74 0.025 31 The results of this Table can be summarized as showing the nitrogen-containing functionalized polymers of the invention to have comparable or superior dispersancy at 1 and 0.5 weight percent add

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tested is cooled and then centrifuged for 30 minutes at about 39,000 gs. Any deposits of new sludge that form in this step are separated from the oil by decanting the supernatant oil and then carefully washing the sludge deposits with 25 ml. of pentane to remove all remaining oil from the sludge. Then the weight of the new solid sludge that has been formed in the test, in milligrams, is determined by drying the residue and weighing it. The results are reported as percent of sludge dispersed by comparison with a blank not containing any additional additive. The less new sludge formed, the larger the value of percent sludge dispersed, and the more effective is the additive as a sludge dispersant. In other words, if the additive is effective, it will hold at least a portion of the new sludge that forms on heating and oxidation stably suspended in the oil so it does not precipitate down during the centrifuging. Using the above-described test, the dispersant action of the several functionalized polymers prepared in accordance with this invention were compared with the dispersing power of a dialyzed product obtained from dialysis of a commercial dispersant previously referred to as Lz 3702. Sufficient dialyzed residue which analyzed about 0.4 weight percent nitrogen, was dissolved in S-150N mineral oil to provide a 10 percent active ingredient concentrate. The dialyzed residue and polymer products of the invention were appropriately diluted in mineral oil to furnish the 0.025, 0.05 and 0.1 weight percent of added additive to the used oil. The test results are given in the Table below. TABLE Product of Example Concentration gms. Percent Sludge No. Product/10 g.Used Oil Dispersed 1 0.1 77.9 0.05 65.2 0.025 41.4 2 0.1 84.8 0.05 53.6 0.025 29.0 3 0.1 76.8 0.05 32.6 0.025 21.5 4 0.1 90 0.05 60.2 5 0.1 88.0 0.05 65.8 6 0.1 90.7 0.05 65.8 7 0.1 80 0.05 64 0.025 22 Dialyzed LZ 3702 0.1 89 (Commercial Dispersant) 0.05 74 0.025 31 The results of this Table can be summarized as showing the nitrogen-containing functionalized polymers of the invention to have comparable or superior dispersancy at 1 and 0.5 weight percent additive levels over that shown by a commercially available multifunctional V.I. improver. WHAT WE CLAIM IS:

1. A lubricating oil composition comprising a major amount of lubricating oil and about 0.1 to 10 wt.% of an oil soluble addition product having a number average molecular weight in the range of 1,000 to 500,000 containing in the range of 0.005 to 10 wt.% nitrogen, said oil soluble addition product being a condensation reaction product of: (1) an anionically polymerizable monomer containing in the range of 3 to 50 carbon atoms and at least one electron withdrawing group in such proximity to a double bond that said bond is activated, said monomer being selected from the group consisting of:

(a) N,N (di C1-lo hydrocarbyl) carbodiimides; (b) monomers of the formula:

wherein Xis oxygen or an NR" group; n is 2 to 5; R' and R" are hydrogen or a C1 to C4 alkyl group; and R!" and R"" are l to C12 hydrocarbyl groups; and (c) nitrile monomers of the formulae:

wherein RV is hydrogen or lower alkyl and X is selected from the group consisting of hydrogen, halogen, cyano and lower alkyl; and (2) an oxidized as hereinbefore defined ethylene copolymer comprising 20 to 80 mole % ethylene and 20 to 80 mole % of a C3 to C50 alphamono-olefin having an oxygen content of from 0.005 to 6 wt % said reaction product being formed by reacting said monomer and copolymer either thermally in the absence of a catalyst at a temperature in the range 100" to 200"C., or at a temperature in the range 0 C to 2000C in the presence of an aqueous solution of strong base having a pH of at least 8 as sole catalyst.

2. A lubricating oil composition according to claim 1, wherein said monomer is said nitrile monomer (c).

3. A lubricating oil composition according to claim 2, wherein said monomer is acrylonitrile.

4. A lubricating oil composition according to any of the preceding claims wherein said molecular weight is in the range of 10,000 to 200,000; and said C3 to C50 alpha-mono-olefin is propylene and said copolymer contains up to 20 mole So, based on the molar amount of ethylene and propylene units, of olefin selected from the group consisting of olefins of the formula RCH=CH2, where R is an aliphatic or cycloaliphatic radical of 2 to 48 carbons and diolefins of 4 to 26 carbon atoms.

5. A lubricating oil composition according to claim 1 substantially as hereinbefore described with particular reference to the accompanying Examples.

6. A process of preparing an oil soluble addition product having a number average molecular weight in the range of 1,000 to 500,000 and containing in the range of 0.005 to 10 wt.% nitrogen, comprising the steps of reacting an oxidized as hereinbefore defined ethylene copolymer comprising about 20 to 80 mole % ethylene and 20 to 80 mole % of a C3 to C50 alpha-mono-olefine and having an oxygen content of from 0.005 to 6%, with an anionical y polymerizable monomer, either thermally in the absence of a catalyst at a temperature between 100" and 200"C., or catalytically at 0 to 2000C in the presence of an aqueous solution of strong base having a pH of at least 8 as sole catalyst, and then recovering said product, and wherein said anionically polymerizable monomer is selected from the group consisting of: (a) N,N (di C1-lo hydrocarbyl) carbodiimides; (b) monomers of the formula:

wherein X is oxygen or an NR" group; n is 2 to 5; R' and R" are hydrogen or a C1 to C4 alkyl group; and R" and R"" are C, to C,2 hydrocarbyl groups; and (c) nitrile monomers of the formulae:

wherein Rv is hydrogen or lower alkyl and X is selected from the group consisting of hydrogen, halogen, cyano and lower alkyl.

7. A process according to claim 6, wherein said monomer is said nitrile monomer (c), and wherein said process is carried out catalytically with said aqueous solution having a pH of at least 11.

8. A process according to claim 7 wherein said monomer is acrylonitrile.

9. A process according to any of claims 6 to 8 wherein said molecular weight is in the range of 10,000 to 200,000, C3 to C50 olefin is propylene and said ethylene copolymer contains up to 20 mole %, based on the molar amount of ethylene and pro ylene units, of olefin selected from the group consisting of olefins of the formula RCH = CH2, where R is an aliphatic or cycloaliphatic radical of 2 to 48 carbons and diolefins of 4 to 26 carbon atoms.

10. A process according to claim 6 substantially as hereinbefore described with reference to the accompanying Examples.

11. An oil soluble addition product having a number average molecular weight in the range of 1,000 to 500,000 while containing the range of 0.005 to 10 wit. % nitrogen, said oil soluble addition product being a condensation reaction product of: (1) an anionically polymerizable monomer containing in the range of 3 to 50 carbon atoms and at least one electron withdrawing group in such proximity to a double bond that said bond is activated, said monomer being selected from the group consisting of: a N,N (di C1-lo hydrocarbyl) carbodiimides: b monomers of the formula:

wherein X is oxygen or an NR" group; n is 2 to 5; R' and R" are hydrogen or a C1 to C4 alkyl group; and R"' and R"" are 1 to C12 hydrocarbyl groups; and (c) nitrile monomers of the formulae:

wherein RV is hydrogen or lower alkyl and X is selected from the group consisting of hydrogen, halogen, cyano and lower alkyl; and (2) an oxidized as hereinbefore defined ethylene copolymer comprising 20 to 80 mole % ethylene and 20 to 80 mole % of a C3 to C50 mono-alpha-olefine having an oxygen content of from 0.005 to 6 wt. % said reaction product being formed by reacting said monomer and copolymer either thermally in the absence of a catalyst at 1000 to 2000C., or at a temperature in the range 0 C to 200"C in the presence of an aqueous solution of strong base having a pH of at least 8 as sole catalyst.

12. An oil soluble addition product according to claim 11, wherein said monomer is said nitrile monomer (c).

13. An oil soluble addition product according to claim 14, wherein said monomer is acrylonitrile.

14. An oil soluble addition product according to claim 13, wherein said molecular weight is in the range of 10,000 to 200,000, said C3 to C50 mono alpha-olefine is propylene and said ethylene copolymer contains up to 20 mole % based on the molar amount of ethylene and propylene units, of olfin selected from the group consisting of olefins of the formula RCH=CH2, where R is an aliphatic or cycloaliphatic radical of 2 to 48 carbons and diolefins of 4 to 26 carbon atoms.

15. An oil soluble addition product according to claim 11 substantially as hereinbefore described with reference to the accompanying Examples.