EP0400874B1

EP0400874B1 - Improved multifunctional viscosity index modifier additives derived from amido amines

Info

Publication number: EP0400874B1
Application number: EP90305579A
Authority: EP
Inventors: Antonio Gutierrez; Robert Dean Lundberg
Original assignee: Exxon Chemical Patents Inc
Current assignee: ExxonMobil Chemical Patents Inc
Priority date: 1989-05-30
Filing date: 1990-05-22
Publication date: 1993-04-21
Anticipated expiration: 2010-05-22
Also published as: BR9002543A; DE69001389T2; AU623525B2; AU5599290A; DE69001389D1; CA2015063A1; EP0400874A1

Description

The invention relates to oil soluble polymeric compositions of matter useful as multifunctional viscosity index improver additives, particular viscosity index improver-dispersant additives, for oleaginous compositions such as fuel and lubricating oil compositions, and to oleaginous compositions containing said additives.
The concept of derivatizing V.I. improving high molecular weight ethylene copolymers, with acid moieties such as maleic anhydride, followed by reaction with an amine to form a V.I.-dispersant oil additive is known as indicated by the following patents.
U.S. Pat. No. 3,316,177 teaches ethylene-propylene-diene, which are heated to elevated temperatures in the presence of oxygen so as to oxidize the polymer and cause its reaction with maleic anhydride which is present during the oxidation. The resulting polymer can then be reacted with alkylene polyamines.
U.S. Pat. No. 4,089,794 teaches grafting the ethylene copolymer with maleic anhydride using peroxide in a lubricating oil solution, wherein the grafting is preferably carried out under nitrogen, followed by reaction with polyamine.
U.S. Pat. No. 4,137,185 teaches reacting C₁ to C₃₀ monocarboxylic acid anhydrides, and dicarboxylic anhydrides, such as acetic anhydride, succinic anhydride, etc. with an ethylene copolymer reacted with maleic anhydride and a polyalkylene polyamine to inhibit cross linking and viscosity increase due to further reaction of any primary amine groups which were initially unreacted.
U.S. Pat. No. 4,144,181 is similar to 4,137,185 in that it teaches using a sulfonic acid to inactivate the remaining primary amine groups when a maleic anhydride grafted ethylene-propylene copolymer is reacted with a polyamine.
U.S. Pat. No. 4,169,063 reacts an ethylene copolymer in the absence of oxygen and chlorine at temperatures of 150° to 250°C with maleic anhydride followed by reaction with polyamine.
A number of prior disclosures teach avoiding the use of polyamine having two primary amine groups to thereby reduce cross-linking problems which become more of a problem as the number of amine moieties added to the polymer molecule is increased in order to increase dispersancy.
German Published Application No. P3025274.5 teaches an ethylene copolymer reacted with maleic anhydride in oil using a long chain alkyl hetero or oxygen-containing amine.
U.S. Pat. No. 4,132,661 grafts ethylene copolymer, using peroxide and/or air blowing, with maleic anhydride and then reacts with a primary-tertiary diamine.
U.S. Pat. No. 4,160,739 teaches an ethylene copolymer which is grafted, using a free-radical technique, with alternating maleic anhydride and a second polymerizable monomer such as methacrylic acid, which materials are reacted with an amine having a single primary, or a single secondary, amine group.
U.S. Pat. No. 4,171,273 reacts an ethylene copolymer with maleic anhydride in the presence of a free-radical initiator and then with mixtures of C₄ to C₁₂ n-alcohol and amine such as N-aminopropylmorpholine or dimethylamino propyl amine to form a V.I.-dispersant pour depressant additive.
U.S. Pat. No. 4,219,432 teaches maleic anhydride grafted ethylene copolymer reacted with a mixture of an amine having only one primary group together with a second amine having two or more primary groups.
German published application No. 2753569.9 shows an ethylene copolymer reacted with maleic anhydride by a free-radical technique and then reacted with an amine having a single primary group.
German published application No. 2845288 grafts maleic anhydride on an ethylene-propylene copolymer by thermal grafting at high temperatures and then reacts with amine having one primary group.
French published application No. 2423530 teaches the thermal reaction of an ethylene copolymer with maleic anhydride at 150°C to 210°C followed by reaction with an amine having one primary or secondary group.
The early patents such as U.S. Pat. Nos. 3,316,177 and 3,326,804 taught the general concept of grafting an ethylene-propylene copolymer with maleic anhydride and then reacting with a polyalkylene polyamine such as polyethylene amines. Subsequently, U.S. Pat. No. 4,089,794 was directed to using an oil solution for free radical peroxide grafting the ethylene copolymer with maleic anhydride and then reacting with the polyamine. This concept had the advantage that by using oil, the entire reaction could be carried out in an oil solution to form an oil concentrate, which is the commercial form in which such additives are sold. This was an advantage over using a volatile solvent for the reactions, which has to be subsequently removed and replaced by oil to form a concentrate. Subsequently, in operating at higher polyamine levels in order to further increase the dispersing effect, increased problems occurred with the unreacted amine groups cross-linking and thereby causing viscosity increase of the oil concentrate during storage and subsequent formation of haze and in some instances gelling. Even though one or more moles of the ethylene polyamine was used per mole of maleic anhydride during imide formation, cross-linking became more of a problem as the nitrogen content of the polymers was increased. One solution was to use the polyamines and then to react the remaining primary amino groups with an acid anhydride, preferably acetic anhydride, of U.S. Pat. No. 4,137,185 or the sulfonic acid or U.S. Pat. No. 4,144,181. The cross-linking problem could also be minimized by avoidance of the ethylene polyamines and instead using amines having one primary group which would react with the maleic anhydride while the other amino groups would be tertiary groups which were substantially unreactive. Patents or published applications showing the use of such primary-tertiary amines noted above are U.S. Pat. No. 4,219,432, wherein a part of the polyamine was replaced with a primary-tertiary amine; U.S. Pat. No. 4,132,661; U.S. Pat. No. 4,160,739; U.S. Pat. No. 4,171,273; German No. P2753569.9; German No. 2,845,288; and French No. 2,423,530.
U.S. Patent No. 4,517,104 discloses polymeric viscosity index (V.I.) improver-dispersant additive for petroleum oils, particularly lubricating oils, comprising a copolymer of ethylene with one or more C₃ to C₂₈ alpha-olefins, preferably propylene, which has been grafted with acid moieties such as maleic anhydride using a free radical initiator in a solvent such as lubricating oil, and then reacted with a carboxylic acid component including hydrocarbyl substituted succinic anhydride or acid having 12-400 carbon atoms in said hydrocarbyl group or long chain monocarboxylic acid, and a polyamine having two or more primary amine groups. Or the grafted polymer may be reacted with said acid component prereacted with said polyamine to form salts, amides, imides, etc. and then reacted with said grafted olefin polymer. These reactions can permit the incorporation of varnish inhibition and dispersancy into the ethylene copolymer while inhibiting cross-linking or gelling.
U.S. Patent No. 4,632,769 discloses oil soluble viscosity index improving ethylene copolymers, such as copolymers of ethylene and propylene, reacted or grafted with ethylenically unsaturated carboxylic acid moieties, preferably maleic anhydride moieties, and then reacted with polyamines having two or more primary amine groups and a C₂₂ to C₂₈ olefin carboxylic acid component. These reactions can permit the incorporation of varnish inhibition and dispersancy into the ethylene copolymer while inhibiting cross-linking or gelling.
U.S. Patent 2,921,085 relates to the preparation of beta-aminopropionamides by reaction of an alkyl amine with an acrylate to form an alkyl aminopropionate and reaction of the latter compound with an amine. The resulting compounds are disclosed to have utility as surface active agents, specifically as emulsifying, wetting, foaming and detergent agents.
U.S. Patent 3,337,609 relates to adducts of hydroxyalkyl alkylene polyamines and acrylates. The resulting adducts are added to polyepoxides to provide compositions which are suitable for use as a barrier coating for polyethylene surfaces, and for additional end uses, such as in molding. In addition, the adducts are disclosed to be useful as catalysts in resin preparation and as corrosion inhibitors in water systems for ferrous metals.
U.S. Patent 3,417,140 relates to the preparation of amido-amine compositions, which are useful as epoxy resin curing agents, by reacting a polyalkylene polyamine and a fatty amine (comprising a mono- or diamine having as one of the substituents on a nitrogen atom a hydrocarbyl radical having 8 to 24 carbon atoms) with an alpha-beta unsaturated carbonylic compound. It is disclosed that this reaction occurs through the Michael addition of an amine group across the unsaturated group of the carbonylic compound and through the condensation of an amine group with the carbonylic group.
U.S. Patent 3,247,163 also relates to curing agents for polyepoxide compositions, which curing agents are prepared by reacting an organic amine and an acrylate.
U.S. Patent 3,445,441 relates to amino-amido polymers characterized by being a reaction product of at least a polyamine and an acrylate type compound, such as methyl or ethyl acrylate, and methyl or ethyl methacrylate. The patent states that the polymers are useful in a wide variety of applications, such as floculating agents, water clarifying additives, corrosion inhibitors in oil and gas wells, and as lube oil additives. The patent further discloses that the polymers may be derivitized, including acylation with monocarboxylic acids and polycarboxylic acids, aliphatic dicarboxylic acids, aromatic dicarboxylic acids, for example, diglycolic, phthalic, succinic, etc., acids.
U.S. Patent 3,903,003 relates to lubricating compositions containing an amido-amine reaction product of a terminally carboxylated isoprene polymer which is formed by reacting a terminally carboxylated substantially completely hydrogenated polyisoprene having an average molecular weight between about 20,000 and 250,000 and a nitrogen compound of the group consisting of polyalkylene amines and hydroxyl polyalkylene amines.
U.S. Patent 4,493,771 relates to scale inhibiting with compounds containing quaternary ammonium and methylene phosphonic acid groups. These compounds are derivatives of polyamines in which the amine hydrogens have been substituted with both methylene phosphonic acid groups or their salts and hydroxypropyl quaternary ammonium halide groups. The patent discloses that any amine that contains reactive amino hydrogens can be utilized, e.g. polyglycol amines, amido-amines, oxyacylated amines and others.
U.S. Patent 4,459,241 contains a similar disclosure to U.S. Patent 4,493,771.
The compositions of the present invention are an improvement over those of the above prior disclosures because of their effectiveness and their ability to provide enhanced lubricating oil dispersancy.
According to one aspect the invention provides an oil soluble composition useful as a multifunctional viscosity improver for oleaginous compositions comprising the adduct of:

(A) high molecular eight ethylene copolymer substituted carboxylic acid material comprising the reaction product of
- (i) an ethylene copolymer having a number average molecular weight M_n of at least 15,000 and
- (ii) monounsaturated carboxylic acid material;
(B) an amido-amine or thioamido-amine comprising the reaction product of at least one polyamine and an alpha, beta-unsaturated compound of the formula:
wherein X is sulfur or oxygen, Y is -OR⁴, -SR⁴, or -NR⁴(R⁵), and R¹, R², R³, R⁴ and R⁵ are the same or different and are independently selected from hydrogen and substituted or unsubstituted hydrocarbyl.

According to another aspect the invention provides a process for producing a composition useful as a multifunctional viscosity improver oil additive which comprises reacting:

(A) high molecular weight ethylene copolymer substituted carboxylic acid material comprising the reaction product of
- (i) an ethylene copolymer having a number average molecular weight M_n of at least 15,000 and
- (ii) monounsaturated carboxylic acid material;
(B) an amido-amine or thioamido-amine compound containing at least one primary amino group comprising the reaction product of
- (i) at least one polyamine and
- (ii) an alpha, beta-unsaturated compound of the formula:
  wherein X is sulfur or oxygen, Y is -OR⁴, -SR⁴, or -NR⁴(R⁵), and R¹, R², R³, R⁴ and R⁵ are the same or different and are independently selected from hydrogen and substituted or unsubstituted hydrocarbyl radicals; wherein said amine compound (B) is introduced into a solution containing said polymeric acid material (A) and heated therewith at a temperature from 100°C to 250°C for a period from 1 to 10 hours, such that at least a portion of said primary amino groups of said amine compound (B) react with at least a portion of the carboxyl groups of said polymeric acid material (A).

Said polymeric acid material (A) may be reacted with said amine compound (B) and also a carboxylic acid component (C), or with the preformed reaction product of (B) and (C).
The compositions of matter of the instant invention comprise high molecular weight, i.e., at least 15,000 number average molecular weight, copolymers of ethylene, preferably copolymers of ethylene and at least one other C₃ to C₂₈ alpha-olefin such as propylene, reacted or grafted with ethylenically unsaturated carboxylic acid material to form a grafted ethylene copolymer, followed by reaction with an amido-amine. These materials are useful as multifunctional viscosity index improved additives, particularly viscosity index improver-dispersant additives for oleaginous compositions such as fuel and lubricating oil compositions.
Oil soluble ethylene copolymers used in the invention are those capable of modifying or improving the viscosity index of oleaginous compositions, particularly lubricating oil compositions, i.e., polymers useful as V.I. improvers. Therefor, they have a number-average molecular weight (M _n) of at least 15,000. These copolymers preferably have number average molecular weights of from 15,000 to 500,000, more preferably 20,000 to 300,000, and most preferably from 30,000 to 150,000. These V.I. improvers will generally have a narrow range of molecular weight, as determined by the ratio of weight-molecular weight (M _w) to number-average molecular weight (M _n). Polymers having a M _w/M _n of less than 10, preferably less than 7, and more preferably 4 or less are most desirable. As used herein (M _n) and (M _w/M _n) are measured by the well known techniques of vapor phase osmometry (VPO), membrane osmometry and gel permeation chromatography. In general, polymers having a narrow range of molecular weight may be obtained by a choice of synthesis conditions such as choice of principal catalyst and cocatalyst combination, addition of hydrogen during the synthesis, etc. Post synthesis treatment such as extrusion at elevated temperature and under high shear through small orifices, mastication under elevated temperatures, thermal degradation, fractional precipitation from solution, etc. may also be used to obtain narrow ranges of desired molecular weights and to break down higher molecular weight polymer to different molecular weight grades for V.I. use.
These polymers are prepared from ethylene and ethylenically unsaturated hydrocarbons including cyclic, alicyclic and acyclic, containing from 3 to 28 carbons, e.g. 2 to 18 carbons. These ethylene copolymers may contain from 15 to 90 wt. % ethylene, preferably 30 to 80 wt. % of ethylene and 10 to 85 wt. %, preferably 20 to 70 wt. % of one or more C₃ to C₂₈, preferably C₃ to C₁₈ more preferably C₃ to C₈, unsaturated hydrocarbons, preferably alpha olefins. While not essential, such copolymers preferably have a degree of crystallinity of less than 25 wt. %, as determined by X-ray diffraction and differential scanning calorimetry. Copolymers of ethylene and propylene are most preferred. Other alpha-olefins suitable in place of propylene to form the copolymer, or to be used in combination with ethylene and propylene, to . form a terpolymer, tetrapolymer, etc., 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc.; also branched chain alpha-olefins, such as 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methylpentene-1, 4,4-dimethyl-1-pentene, and 6-methylheptene-1, etc., and mixtures thereof.
The term copolymer as used herein, unless otherwise indicated, includes terpolymers, tetrapolymers, etc., of ethylene, said C3-28 alpha-olefin and/or a non-conjugated diolefin or mixtures of such diolefins which may also be used. The amount of the non-conjugated diolefin will generally range from 0.5 to 20 mole percent, preferably 1 to 7 mole percent, based on the total amount of ethylene and alpha-olefin present.
Representative examples of non-conjugated dienes that may be used as the third monomer in the terpolymer include:

a. Straigth chain acyclic dienes such as: 1,4-hexadiene; 1,5-heptadiene; 1,6-octadiene.
b. Branched chain acyclic dienes such as: 5-methyl-1,4-hexadiene; 3,7-dimethyl 1,6octadiene; 3,7-dimethyl 1,7-ocatdiene; and the mixed isomers of dihydro-myrcene and dihydro-cymene.
c. Single ring alicyclic dienes such as: 1,4-cyclohexadiene; 1,5-cyclooctadiene; 1,5-cyclododecadiene; 4-vinylcyclohexene; 1-allyl-4-isopropylidene cyclohexane; 3-allyl-cyclopentene; 4-allyl-cyclohexene and 1-isopropenyl-4-(4-butenyl) cyclohexane.
d. Multi-single ring alicyclic dienes such as: 4,4'-dicyclopentenyl and 4,4'-dicyclohexenyl dienes.
e. Multi-ring alicyclic fused and bridged ring dienes such as: tetrahydroindene; methyl tetrahydroindene; dicyclopentadiene; bicyclo (2.2.1) hepta-2,5-diene; alkyl, alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes such as: ethyl norbornene; 5-methylene-6-methyl-2-norbornene; 5-methylene-6,6-dimethyl-2-norbornene; 5-propenyl-2-norbornene; 5-(3-cyclopentenyl)2-norbornene and 5-cyclohexylidene-2-norbornene; norbornadiene; etc.

CARBOXYLIC ACID MATERIAL

The carboxylic acid material which is grafted to or reacted with the ethylene copolymer to form the grafted ethylene copolymer is preferably ethylenically unsaturated, preferably monounsaturated, carboxylic acid material and can be either a monocarboxylic or dicarboxylic acid material. The dicarboxylic acid materials include (i) monounsaturated C₄ to C₁₀ dicarboxylic acid wherein (a) the carboxyl groups are vicinyl, i.e., located on adjacent carbon atoms, and (b) at least one, preferably both, of said adjacent carbon atoms are part of said monounsaturation; and (ii) derivatives of (i) such as anhydrides or C₁ to C₅ alcohol derived mono- or diesters of (i). Upon reaction with the ethylene copolymer the monounsaturation of the dicarboxylic acid, anhydride, or ester becomes saturated. Thus, for example, maleic anhydride becomes an ethylene copolymer substituted succinic anhydride.
The monocarboxylic acid materials include (i) monounsaturated C₃ to C₁₀ monocarboxylic acid wherein the carbon-carbon bond is conjugated to the carboxy group, i.e., of the structure

and
(ii) derivatives of (i) such as C₁ to C₅ alcohol derived monoesters of (i). Upon reaction with the ethylene copolymer, the monounsaturation of the monounsaturated carboxylic acid material becomes saturated. Thus, for example, acrylic acid becomes an ethylene copolymer substituted propionic acid, and methacrylic acid becomes an ethylene copolymer substituted isobutyric acid.
Exemplary of such unsaturated mono- and dicarboxylic acids, or anhydrides and thereof include fumaric acid, itaconic acid, maleic acid, maleic anhydride, chloromaleic anhydride, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, etc.
Preferred carboxylic acid materials are the dicarboxylic acid anhydrides. Maleic anhydride or a derivative thereof is particularly preferred as it does not appear to homopolymerize appreciably but grafts onto the ethylene copolymer to give two carboxylic acid functionalities. Such preferred materials have the generic formula

wherein R' and R'' are independently hydrogen or a halogen.
Additionally, as taught by U.S. Patent Nos. 4,160,739 and 4,161,452, both of which are incorporated herein by reference, various unsaturated comonomers may be grafted on the ethylene copolymer together with the unsaturated carboxylic acid material. Such graft monomer systems may comprise one or a mixture of comonomers different from said unsaturated carboxylic acid material, and which contain only one copolymerizable double bond and are copolymerizable with said unsaturated acid component.
Typically, such comonomers do not contain free carboxylic acid groups and are esters containing alpha-ethylenic unsaturation in the acid or alcohol portion; hydrocarbons, both aliphatic and aromatic, containing , alpha-ethylenic unsaturation, such as the C₄-C₁₂ alpha olefins, for example hexene, nonene, dodecene, etc.; styrenes, for example styrene, alpha-methyl styrene, p-methyl styrene, butyl styrene, etc.; and vinyl monomers, for example vinyl acetate, vinyl chloride, vinyl ketones such as methyl and ethyl vinyl ketone, and nitrogen containing vinyl monomer such as vinyl pyridine and vinyl pyrrolidine, etc. Comonomers containing functional groups which may cause crosslinking, gelation or other interfering reactions should be avoided, although minor amounts of such comonomers (up to about 10% by weight of the comonomer system) often can be tolerated.
Specific useful copolymerizable comonomers include the following:

(A) Esters of saturated acids and unsaturated alcohols wherein the saturated acids may be monobasic or polybasic acids containing up to about 40 carbon atoms such as the following: acetic, propionic, butyric, valeric, caproic, stearic, oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, phthalic, isophthalic, terephthalic, hemimellitic, trimellitic, trimesic and the like, including mixtures. The unsaturated alcohols may be monohydroxy or polyhydroxy alcohols and may contain up to about 40 carbon atoms, such as the following: allyl, methallyl, crotyl, 1-chloroallyl, 2-chloroallyl, cinnamyl, vinyl, methyl vinyl, 1-phenallyl, butenyl, propargyl, 1-cyclohexene-3-ol, oleyl, and the like, including mixtures.
(B) Esters of unsaturated monocarboxylic acids containing up to about 12 carbon atoms such as acrylic, methacrylic and crotonic acid, and an esterifying agent containing up to about 50 carbon atoms, selected from saturated alcohols and alcohol epoxides. The saturated alcohols may preferably contain up to about 40 carbon atoms and include monohydroxy compounds such as: methanol, ethanol, propanol, butanol, 2-ethylhexanol, octanol, dodecanol, cyclohexanol, cyclopentanol, neopentyl alcohol, and benzyl alcohol; and alcohol ethers such as the monomethyl or monobutyl ethers of ethylene or propylene glycol, and the like, including mixtures. The alcohol epoxides include fatty alcohol epoxides, glycidol, and various derivatives of alkylene oxides, epichlorohydrin, and the like, including mixtures.

The components of the graft copolymerizable system are used in a ratio of unsaturated carboxylic acid material monomer component to comonomer component of about 1:4 to 4:1, preferably about 12 to 2:1 by weight.

GRAFTING OF THE ETHYLENE COPOLYMER

The grafting of the ethylene copolymer with the carboxylic acid material may be by any suitable method, such as thermally by the "ene" reaction, using copolymers containing unsaturation, such as ethylene-propylene-diene polymers either chlorinated or unchlorinated, or more preferably it is by free-radical induced grafting in solvent, preferably in a mineral lubricating oil as solvent.
The radical grafting is preferably carried out using free radical initiators such as peroxides, hydroperoxides, and azo compounds and preferably those which have a boiling point greater than about 100°C. and which decompose thermally within the grafting temperature range to provide said free radicals. Representative of these free-radical initiators are azobutyro-nitrile, 2,5-dimethyl-hex-3-yne-2, 5 bis-tertiary-butyl peroxide (sold. as Lupersol 130) or its hexane analogue, di-tertiary butyl peroxide and dicumyl peroxide. The initiator is generally used at a level of between about 0.005% and about 1%, based on the total weight of the polymer solution, and temperatures of about 150 to 220°C.
The ethylenically unsaturated carboxylic acid material, such as maleic anhydride, will be generally used in an amount ranging from about 0.01% to about 10%, preferably 0.1 to 2.0%, based on weight of the initial total solution. The aforesaid carboxylic acid material and free radical initiator are generally used in a weight percent ratio range of 1.0:1 to 30:1, preferably 3.0:1 to 6:1.
The initiator grafting is preferably carried out in an inert atmosphere, such as that obtained by nitrogen blanketing. While the grafting can be carried out in the presence of air, the yield of the desired graft polymer is generally thereby decreased as compared to grafting under an inert atmosphere substantially free of oxygen. The grafting time will usually range from 0.1 to 12 hours, preferably from 0.5 to 6 hours, more preferably 0.5 to 3 hours. The graft reaction will be usually carried out to at least approximately 4 times, preferably at least 6 times the half-life of the free-radical initiator at the reaction temperature employed, e.g. with 2,5-dimethyl hex-3-yne-2, 5-bis(t-butyl peroxide) 2 hours at 160°C. and one hour at 170°C., etc.
In the grafting process, usually the copolymer solution is first heated to grafting temperature and thereafter said unsaturated carboxylic acid material and initiator are added with agitation, although they could have been added prior to heating. When the reaction is complete, the excess acid material can be eliminated by an inert gas purge, e.g. nitrogen sparging. Preferably the carboxylic acid material that is added is kept below its solubility limit in the polymer solution, e.g. below about 1 wt. %, preferably below 0.4 wt. % or less, of free maleic anhydride based on the total weight of polymer-solvent solution, e.g. ethylene copolymer mineral lubricating oil solution. Continuous or periodic addition of the carboxylic acid material along with an appropriate portion of initiator, during the course of the reaction, can be utilized to maintain the carboxylic acid below its solubility limits, while still obtaining the desired degree of total grafting.
In the initiator grafting step the maleic anhydride or other carboxylic acid material used will be grafted onto both the polymer and the solvent for the reaction. Many solvents such as dichlorobenzene are relatively inert and may be only slightly grafted, while mineral oil will tend to be more grafted. The exact split of graft between the substrate present depends upon the polymer and its reactivity, the reactivity and type of oil, the concentration of the polymer in the oil, and also upon the maintenance of the carboxylic acid material in solution during the course of the reaction and minimizing the presence of dispersed, but undissolved acid, e.g. the maleic anhydride. The undissolved acid material appears to have an increased tendency to react to form oil insoluble materials as opposed to dissolved acid material. The split between grafted oil and grafted polymer may be measured empirically from the infrared analyses of the product dialyzed into oil and polymer fractions.
The grafting is preferably carried out in a mineral lubricating oil which need not be removed after the grafting step but can be used as the solvent in the subsequent reaction of the graft polymer with the amine material and as a solvent for the end product to form the lubricating additive concentrate. The oil having attached, grafted carboxyl groups, when reacted with the amine material will also be converted to the corresponding derivatives.
The solution grafting step when carried out in the presence of a high temperature decomposable peroxide can be accomplished without substantial degradation of the chain length (molecular weight) of the ethylene containing polymer. This can be an advantage as opposed to high temperature thermal reactions which depend on degradation to apparently form free radical reactive sites. Measurement of molecular weights and degradation can be evaluated by determination of the thickening efficiency (T.E.) of the polymer as will later be described.
The amount of carboxylic acid material used in the grafting reaction is an amount which is effective to provide a grafted ethylene copolymer which upon further reaction with an amido-amine as described hereinafter provides a material exhibiting the properties of a multifunctional viscosity index improver additive, more specifically a viscosity index improver-dispersant additive, i.e., a material having both V.I. improving and dispersancy properties in an oleaginous composition. That is to say, an amount which is effective to provide, upon reaction of the grafted ethylene copolymer with the amido amine, an oleaginous composition exhibiting improved viscometric and dispersancy properties. Generally, this amount of grafting material, e.g., moles of carboxylic acid material such as maleic anhydride, is an amount which is effective to provide a grafted ethylene copolymer, e.g., ethylene-alpha-olefin substituted carboxylic acid material such as ethylene- propylene substituted succinic anhydride, containing an average number of acid material moieties, e.g., succinic anhydride, grafted to or present on a 10,000 number average molecular weight segment of a mole of ethylene copolymer of at least 0.1, preferably at least 0.5, and more preferably at least 1. The maximum average number of grafted moieties present per 10,000 average number molecular weight segment of a mole of ethylene copolymer backbone should not exceed 10, preferably 7 and more preferably 5. Preferably, the average number, moles, of grafted moieties present per mole of ethylene copolymer backbone is at least 0.6, preferably at least 0.8, and more preferably at least 1. Preferably, the maximum average number of grafted moieties grafted to or present per mole of ethylene copolymer backbone should generally not exceed 10, preferably 7, and more preferably 5. Thus, for example, a mole of grafted ethylene copolymer, e.g., ethylene- propylene substituted succinic anhydride, containing an ethylene copolymer backbone such as an ethylene- propylene backbone having an average number molecular weight of 50,000 contains grafted to said backbone an average number of succinic anhydride moieties of from 0.5 to 50, preferably from 0.6 to 10. Typically, from 0.2 to 12, preferably from 0.4 to 6 moles of said carboxylic acid material are charged to the reactor per mole of ethylene copolymer charged.
Normally, not all of the ethylene copolymer reacts with the carboxylic acid material, e.g., maleic anhydride, to produce a grafted ethylene copolymer, e.g., ethylene-propylene substituted succinic anhydride. The resultant reaction product mixture, therefore, contains reacted or grafted ethylene copolymer, e.g., ethylene-propylene substituted succinic anhydride, unreacted or ungrafted ethylene copolymer, and unreacted grafting material, e.g., maleic anhydride. The unreacted ethylene copolymer is typically not removed from the reaction product mixture, and the reaction product mixture, generally stripped of any unreacted grafting material, is utilized as is or is employed for further reaction with the amine as described hereinafter.
Characterization of the average number of moles of carboxylic acid material, e.g., maleic anhydride, which have reacted per mole of ethylene copolymer charged to the reaction (whether it has undergone reaction or not) is defined herein as the average number of grafted moieties grafted to or present per mole of ethylene copolymer backbone. This number is defined solely with reference to the resulting reaction product mixture. Although the amount of said unreacted ethylene copolymer contained in the resulting reaction product mixture can be subsequently modified, i.e., increased or decreased by techniques known in the art, such modifications do not alter the average number of grafted moieties as defined above. The term grafted ethylene copolymer is intended to refer to the reaction product mixture whether it has undergone such modification or not.

AMIDO-AMINE

As described above, the amido-amine comprises a reaction product of at least a polyamine and an alpha, beta ethylenically unsaturated compound of formula (I) above.
The polyamines useful in this invention comprise polyamines, most preferably polyalkylene polyamines, preferably of 2 to 60, m or preferably 2 to 40 (e.g. 3 to 20), total carbon atoms and preferably 2 to 12, more preferably 3 to 12, and most preferably at least 5 (e.g., 5 to 9) nitrogen atoms in the molecule. These amines may be hydrocarbyl amines or may be hydrocarbyl amines including other groups, e.g, hydroxy groups, alkoxy groups, amide groups, nitriles, imidazoline groups, and the like. Hydroxy amines with 1 to 6 hydroxy groups, preferably 1 to 3 hydroxy groups are particularly useful. Preferred amines are aliphatic saturated amines, including those of the general formulas:

wherein R, R', R'' and R‴ are independently selected from alkylene radicals; and C₁ to C₁₂ alkylamino C₂ to C₆ alkylene radicals; and wherein R‴ can additionally comprise a moiety of the formula:

wherein R' is as defined above, and wherein s and s' can be the same or a different number of from 2 to 6, preferably 2 to 4; and t and t' can be the same or different and are numbers of from 0 to 10, preferably 2 to 7, and most preferably about 3 to 7, with the proviso that the sum of t and t' is not greater than 15. To assure a facile reaction, it is preferred that R, R', R'', R‴, s, s', t and t' be selected in a manner sufficient to provide the compounds of Formulas II and III with typically at least one primary or secondary amine group, preferably at least two primary or secondary amine groups. This can be achieved by selecting at least one of said R, R', R'' or R‴ groups to be hydrogen or by letting t in Formula III be at least one when R‴ is H or when the IV moiety possesses a secondary amino group. The most preferred amine of the above formulas are represented by Formula III and contain at least two primary amine groups and at least one, and preferably at least three, secondary amine groups.
Non-limiting examples of suitable amine compounds include: 1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethylene amines such as diethylene triamine; triethylene tetramine; tetraethylene pentamine; polypropylene amines such as 1,2-propylene diamine; di-(1,2-propylene)triamine; di-(1,3-propylene) triamine; N,N-dimethyl-1,3-diaminopropane; N,N-di-(2-aminoethyl) ethylene diamine; N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propane diamine; aminopropane; N,N-di-(2-aminoethyl) ethylene diamine; N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propane diamine; tris hydroxymethylaminomethane (THAM); diisopropanol amine; diethanol amine; triethanol amine; mono-, di-, and tri-tallow amines; amino morpholines such as N-(3-aminopropyl)morpholine; and mixtures thereof.
Other useful amine compounds include: alicyclic diamines such as 1,4-di(aminomethyl) cyclohexane, and heterocyclic nitrogen compounds such as imidazolines, and N-aminoalkyl piperazines of the general formula (V):

wherein p₁ and p₂ are the same or different and are each integers of from 1 to 4, and n₁, n₂ and n₃ are the same or different and are each integers of from 1 to 3. Non-limiting examples of such amines include 2-pentadecyl imidazoline: N-(2-aminoethyl) piperazine; etc.
Commercial mixtures of amine compounds may advantageously be used. For example, one process for preparing alkylene amines involves the reaction of an involves the reaction of an alkylene dihalide (such as ethylene dichloride or propylene dichloride) with ammonia, which results in a complex mixture of alkylene amines wherein pairs of nitrogens are joined by alkylene groups, forming such compounds as diethylene triamine, triethylenetetramine, tetraethylene pentamine and isomeric piperazines. Low cost poly(ethyleneamines) compounds averaging about 5 to 7 nitrogen atoms per molecule are available commercially under trade names such as "Polyamine H", "Polyamine 400", "Dow Polyamine E-100", etc.

where m has a value of about 3 to 70 and preferably 10 to 35; and

where "n" has a value of about 1 to 40 with the provision that the sum of all the n's is from about 3 to about 70 and preferably from about 6 to about 35, and R is a polyvalent saturated hydrocarbon radical of up to ten carbon atoms wherein the number of substituents on the R group is represented by the value of "a", which is a number of from 3 to 6. The alkylene groups in either formula (VI) or (VII) may be straight or branched chains containing about 2 to 7, and preferably about 2 to 4 carbon atoms.
The polyoxyalkylene polyamines of formulas (VI) or (VII) above, preferably polyoxyalkylene diamines and polyoxyalkylene triamines, may have average molecular weights ranging from about 200 to about 4000 and preferably from about 400 to about 2000. The preferred polyoxyalkylene polyoxyalkylene polyamines include the polyoxyethylene and polyoxypropylene diamines and the polyoxypropylene triamines having average molecular weights ranging from about 200 to 2000. The polyoxyalkylene polyamines are commercially available and may be obtained, for example, from the Jefferson Chemical Company, Inc. under the trade name "Jeffamines D-230, D-400, D-1000, D-2000, T-403", etc.
Additional amines useful in the present invention are described in U.S. Patent 3,445,441.
Thus, any polyamine, whether aliphatic, cycloaliphatic, aromatic, heterocyclic, etc., can be employed provided it is capable of adding across the acrylic double bond and amidifying with for example the carbonyl group (-C(O)-) of the acrylate-type compound of formula I, or with the thiocarbonyl group (-C(S)-) of the thioacrylate-type compound of formula I.
The alpha, beta ethylenically unsaturated compounds employed in this invention comprise at least one member selected from the group consisting of alpha, beta ethylenically unsaturated compounds of the formula:

wherein X is sulfur or oxygen, Y is -OR⁴, -SR⁴, or -NR⁴(R⁵), and R¹, R², R³, R⁴ and R⁵ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl.
When R¹, R², R³, R⁴ or R⁵ are hydrocarbyl, these groups can comprise alkyl, cycloalkyl, aryl, alkaryl, aralkyl or heterocyclic, which can be substituted with groups which are substantially inert to any component of the reaction mixture under conditions selected for preparation of the amido-amine. Such substituent groups include hydroxy, halide (e.g., Cl, Fl, I, Br), -SH and alkylthio. When one or more of R¹ through R⁵ are alkyl, such alkyl groups can be straight or branched chain, and will generally contain from 1 to 20, more usually from 1 to 10, and preferably from 1 to 4, carbon atoms. Illustrative of such alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tridecyl, hexadecyl, octadecyl and the like. When one or more of R¹ through R⁵ are aryl, the aryl group will generally contain from 6 to 10 carbon atoms (e.g., phenyl, naphthyl).
When one or more of R¹ through R⁵ are alkaryl, the alkaryl group will generally contain from about 7 to 20 carbon atoms, and preferably from 7 to 12 carbon atoms. Illustrative of such alkaryl groups are tolyl, m-ethylphenyl, o-ethyltolyl, and m-hexyltolyl. When one or more of R¹ through R⁵ are aralkyl, the aryl component generally consists of phenyl or (C₁ to C₆) alkyl-substituted phenol and the alkyl component generally contains from 1 to 12 carbon atoms, and preferably from 1 to 6 carbon atoms. Examples of such aralkyl groups are benzyl, o-ethylbenzyl, and 4-isobutylbenzyl. When one or more of R¹ and R⁵ are cycloalkyl, the cycloalkyl group will generally contain from 3 to 12 carbon atoms, and preferably from 3 to 6 carbon atoms. Illustrative of such cycloalkyl groups are cyclopropyl, cyclobutyl, cyclohexyl, cyclooctyl, and cyclododecyl. When one or more of R¹ through R⁵ are heterocyclic, the heterocyclic group generally consists of a compound having at least one ring of 6 to 12 members in which on or more ring carbon atoms is replaced by oxygen or nitrogen. Examples of such heterocyclic groups are furyl, pyranyl, pyridyl, piperidyl, dioxanyl, tetrahydrofuryl, pyrazinyl and 1,4-oxazinyl.
The alpha, beta ethylenically unsaturated carboxylate compounds employed herein have the following formula:

wherein R¹, R², R³, and R⁴ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of such alpha, beta-ethylenically unsaturated carboxylate compounds of formula VIII are acrylic acid, methacrylic acid, the methyl, ethyl, isopropyl, n-butyl, and isobutyl esters of acrylic and methacrylic acids, 2-butenoic acid, 2-hexenoic acid, 2-decenoic acid, 3-methyl-2-heptenoic acid, 3-methyl-2-butenoic acid, 3-phenyl-2-propenoic acid, 3-cyclohexyl-2-butenoic acid, 2-methyl-2-butenoic acid, 2-propyl-2-propenoic acid, 2-isopropyl-2-hexenoic acid, 2,3-dimethyl-2-butenoic acid, 3-cyclohexyl-2-methyl-2-pentenoic acid, 2-propenoic acid, methyl 2-propenoate, methyl 2-methyl 2-propenoate, methyl 2-butenoate, ethyl 2-hexenoate, isopropyl 2-decenoate, phenyl 2-pentenoate, tertiary butyl 2-propenoate, octadecyl 2-propenoate, dodecyl 2-decenoate, cyclopropyl 2,3-dimethyl-2-butenoate, methyl 3-phenyl-2-propenoate, and the like.
The alpha, beta ethylenically unsaturated carboxylate thioester compounds employed herein have the following formula:

wherein R¹, R², R³, and R⁴ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of such alpha, beta-ethylenically unsaturated carboxylate thioesters of formula IX are methylmercapto 2-butenoate, ethylmercapto 2-hexenoate, isopropylmercapto 2-decenoate, phenylmercapto 2-pentenoate, tertiary butylmercapto 2-propenoate, octadecylmercapto 2-propenoate, dodecylmercapto 2-decenoate, cyclopropylmercapto 2,3-dimethyl-2-butenoate, methylmercapto 3-phenyl-2-propenoate, methylmercapto 2-propenoate, methylmercapto 2-methyl-2-propenoate, and the like.
The alpha, beta ethylenically unsaturated carboxyamide compounds employed herein have the following formula:

wherein R¹, R², R³, R⁴ and R⁵ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of alpha, beta-ethylenically unsaturated carboxyamides of formula X are 2-butenamide, 2-hexenamide, 2-decenamide, 3-methyl-2-heptenamide, 3-methyl-2-butenamide, 3-phenyl-2-propenamide, 3-cyclohexyl-2-butenamide, 2-methyl-2-butenamide, 2-propyl-2-propenamide, 2-isopropyl-2-hexenamide, 2,3-dimethyl-2-butenamide, 3-cyclohexyl-2-methyl-2-pentenamide, N-methyl 2-butenamide, N,N-diethyl 2-hexenamide, N-isopropyl 2-decenamide, N-phenyl 2-pentenamide, N-tertiary butyl 2-propenamide, N-octadecyl 2-propenamide, N-N-didodecyl 2-decenamide, N-cyclopropyl 2,3-dimethyl-2-butenamide, N-methyl 3-phenyl-2-propenamide, 2-propenamide, 2-methyl-2-propenamide, 2-ethyl-2-propenamide and the like.
The alpha, beta ethylenically unsaturated thiocarboxylate compounds employed herein have the following formula:

wherein R¹, R², R³, and R⁴ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of alpha, beta-ethylenically unsaturated thiocarboxylate compounds of formula XI are 2-butenthioic acid, 2-hexenthioic acid, 2-decenthioic acid, 3-methyl-2-heptenthioic acid, 3-methyl-2-butenthioic acid, 3-phenyl-2-propenthioic acid, 3-cyclohexyl-2-butenthioic acid, 2-methyl-2-butenthioic acid, 2-propyl-2-propenthioic acid, 2-isopropyl-2-hex enthioic acid, 2,3-dimethyl-2-butenthioic acid, 3-cyclohexyl-2-methyl-2-pententhioic acid, 2-propenthioic acid, methyl 2-propenthioate, methyl 2-methyl 2-propenthioate, methyl 2-butenthioate, ethyl 2-hexenthioate, isopropyl 2-decenthioate, phenyl 2-pententhioate, tertiary butyl 2-propenthioate, octadecyl 2-propenthioate, dodecyl 2-decenthioate, cyclopropyl 2,3-dimethyl-2-butenthioate, methyl 3-phenyl-2-propenthioate, and the like.
The alpha, beta ethylenically unsaturated dithioic acid and acid ester compounds employed herein have the following formula:

wherein R¹, R², R³, and R⁴ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of alpha, beta-ethylenically unsaturated dithioic acids and acid esters of formula XII are 2-butendithioic acid, 2-hexendithioic acid, 2-decendithioic acid, 3-methyl-2-heptendithioic acid, 3-methyl-2-butendithioic acid, 3-phenyl-2-propendithioic acid, 3-cyclohexyl-2-butendithioic acid, 2-methyl-2-butendithioic acid, 2-propyl-2-propendithioic acid, 2-isopropyl-2-hexendithioic acid, 2,3-dimethyl-2-butendithioic acid, 3-cyclohexyl-2-methyl-2-pentendithioic acid, 2-propendithioic acid, methyl 2-propendithioate, methyl 2-methyl 2-proendithioate, methyl 2-butendithioate, ethyl 2-hexendithioate, isopropyl 2-decendithioate, phenyl 2-pentendithioate, tertiary butyl 2-propendithioate, octadecyl 2-propendithioate, dodecyl 2-decendithioate, cyclopropyl 2,3-dimethyl-2-butendithioate, methyl 3-phenyl-2-propendithioate, and the like.
The alpha, beta ethylenically unsaturated thiocarboxyamide compounds employed herein have the following formula:

wherein R¹, R², R³, R⁴ and R⁵ are the same or different and are hydrogen or substituted or unsubstituted hydrocarbyl as defined above. Examples of alpha, beta-ethylenically unsaturated thiocarboxyamides of formula XIII are 2-butenthioamide, 2-hexenthioamide, 2-decenthioamide, 3-methyl-2-heptenthioamide, 3-methyl-2-butenthioamide, 3-phenyl-2-propenthioamide, 3-cyclohexyl-2-butenthioamide, 2-methyl-2-butenthioamide, 2-propyl-2-propenthioamide, 2-isopropyl-2-hexenthioamide, 2,3-dimethyl-2-butenthioamide, 3-cyclohexyl-2-methyl-2-pententhioamide, N-methyl 2-butenthioamide, N,N-diethyl 2-hexenthioamide, N-isopropyl 2-decenthioamide, N-phenyl 2-pententhioamide, N-tertiary butyl 2-propenthioamide, N-octadecyl 2-propenthioamide, N-N-didodecyl 2-decenthioamide, N-cyclopropyl 2,3-dimethyl-2-butenthioamide, N-methyl 3-phenyl-2-propenthioamide, 2-propenthioamide, 2-methyl-2-propenthioamide, 2-ethyl-2-propenthioamide and the like.
Preferred compounds for reaction with the polyamines in accordance with this invention are lower alkyl esters of acrylic and (lower alkyl) substituted acrylic acid. Illustrative of such preferred compounds are compounds of the formula:

where R³ is hydrogen or a C₁ to C₄ alkyl group, such as methyl, and R⁴ is hydrogen or a C₁ to C₄ alkyl group, capable of being removed so as to form an amido group, for example, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, aryl, hexyl, etc. In the preferred embodiments these compounds are acrylic and methacrylic esters such as methyl, ethyl or propyl acrylate, methyl, ethyl or propyl methacrylate. When the selected alpha, beta-unsaturated compound comprises a compound of formula I wherein X is oxygen, the resulting reaction product with the polyamine contains at least one amido linkage (-C(O)N<) and such materials are herein termed "amido-amines." Similarly, when the selected alpha, beta unsaturated compound of formula I comprises a compound wherein X is sulfur, the resulting reaction product with the polyamine contains thioamide linkage (-C(S)N<) and these materials are herein termed "thioamido-amines." For convenience, the following discussion is directed to the preparation and use of amido-amines, although it will be understood that such discussion is also applicable to the thioamido-amines.
The type of amido-amine formed varies with reaction conditions. For example, a more linear amido-amine is formed where substantially equimolar amounts of the unsaturated carboxylate and polyamine are reacted. The presence of excesses of the ethylenically unsaturated reactant of formula I tends to yield an amido-amine which is more cross-linked than that obtained where substantially equimolar amounts of reactants are employed. Where for economic or other reasons a cross-linked amido-amine using excess amine is desired, generally a molar excess of the ethylenically unsaturated reactant of about at least 10%, such as 10-300%, or greater, for example, 25-200%, is employed. For more efficient cross-linking an excess of carboxylated material should preferably be used since a cleaner reaction ensues. For example, a molar excess of about 10-100% or greater such as 10-50%, but preferably an excess of 30-50%, of the carboxylated material. Larger excess can be employed if desired.
In summary, without considering other factors, equimolar amounts of reactants tend to produce a more linear amido-amine whereas excess of the formula I reactant tends to yield a more cross-linked amido-amine. It should be noted that the higher the polyamine (i.e., in greater the number of amino groups on the molecule) the greater the statistical probability of cross-linking since, for example, a tetraalkylenepentamine, such as tetraethylene pentamine

has more labile hydrogens than ethylene diamine.
The amido-amine adducts formed in accordance with the present invention are characterised by both amido and amine groups as represented, for example, by the the following formula:

where Z is a unit represented by the following idealized formula:

wherein the R's, which may be the same or different, are hydrogen or a substituted group such as a hydrocarbyl group, for example alkyl, alkenyl or aryl and A is a moiety of the polyamine such as alkyl, aryl or cycloalkyl, and n is an integer from 1 to 10 or greater. The amido-amine adducts preferably contain an average of from 1 to 3 amido groups per molecule of the amido-amine adduct.
The above simplified formula represents a linear amido-amine polymer. However, cross-linked polymers may also be formed by employing certain conditions since the polymer has labile hydrogens which can further react with either the unsaturated moiety by adding across the double bond or by amidifying with a carboxylate group.
Preferably, however, the amido-amines of this invention are not cross-linked to any substantial degree, and more preferably are substantially linear.
Preferably, the polyamine reactant contains at least one primary amine (and more preferably from 2 to 4 primary amines) group per molecule, and the polyamine and the unsaturated reactant of formula I are contacted in an amount of from about 1 to 10, more preferably from about 2 to 6, and most preferably from about 3 to 5, equivalents of primary amine in the polyamine reactant per mole of the unsaturated reactant of formula I.
The reaction between the selected polyamine and acrylate-type compound is carried out at any suitable temperature. Temperatures up to the decomposition points of reactants and products can be employed. In practice, one generally carries out the reaction by heating the reactants below 100°C, such as 80-90°C, for a suitable period of time, such as a few hours. Where an acrylic-type ester is employed, the progress of the reaction can be judged by the removal of the alcohol in forming the amide. During the early part of the reaction alcohol is removed quite readily below 100°C in the case of low boiling alcohols such as methanol or ethanol. As the reaction slows, the temperature is raised to push the polymerization to completion and the temperature may be raised to 150°C toward the end of the reaction. Removal of alcohol is a convenient method of judging the progress and completion of the reaction which is generally continued until no more alcohol is evolved. Based on removal of alcohol, the yields are generally stoichiometric. In more difficult reactions, yield of at least 95% are generally obtained.
Similarly, it will be understood that the reaction of an ethylenically unsaturated carboxylate thioester of formula IX liberates the corresponding HSR⁴ compound (e.g., H₂S when R⁴ is hydrogen) as a by-product, and the reaction of an ethylenically unsaturated carboxyamide of formula X liberates the corresponding HNR⁴(R⁵) compound (e.g., ammonia when R⁴ and R⁵ are each hydrogen) as by-product.
The reaction time involved can vary widely depending on a wide variety of factors. For example, there is a relationship between time and temperature. In general, lower temperature demands longer times. Usually, reaction times of from about 2 to 30 hours, such as 5 to 25 hours, and preferably 3 to 10 hours will be employed.
Although one can employ a solvent, the reaction can be run without the use of any solvent. In fact, where a high degree of cross-linking is desired, it is preferably to avoid the use of a solvent and most particularly to avoid a polar solvent such as water. However, taking into consideration the effect of solvent on the reaction, where desired, any suitable solvent can be employed, whether organic or inorganic, polar or non-polar.
As an example of the amido-amine adducts, the reaction of tetraethylene pentaamine (TEPA) with methyl acrylate can be illustrated as follows:

REACTION OF GRAFTED ETHYLENE COPOLYMER WITH AMIDO AMINE

The grafted high molecular weight ethylene copolymer, preferably in solution, such as an oil solution, containing 5 to 95 wt.%, preferably 5 to 30 wt. %, and more preferably 10 to 20 wt.% of said grafted ethylene copolymer, is readily reacted with the amido-amine by introducing the amido amine into said grafted ethylene copolymer containing solution and heating at a temperature of from about 100°C to 250°C, preferably from 125 to 175°C, for from about 1 to 10 hours, usually about 2 to about 6 hours. The heating is preferably carried out, in the case of ethylene copolymer substituted dicarboxylic acid material, to favor formation of imides or mixtures of imides and amides rather than amides and salts. In the case of ethylene copolymer substituted monocarboxylic acid material heating is preferably carried out to favor formation of amides rather than salts. Removal of water assures completion of the imidation/ amidation reaction. Reaction ratios can vary considerably, depending upon the reactants, amounts of excess, type of bonds formed, etc. Generally, from about 1 to 5, preferably from about 1.5 to 3 moles of ethylene copolymer substituted monocarboxylic or dicarboxylic acid moiety content, e.g., grafted succinic anhydride content, is used per equivalent of amido amine reactant, e.g., amine.
An example of the reaction of an amido amine reactant with ethylene copolymer substituted dicarboxylic acid material is the reaction of ethylene-propylene copolymer substituted succinic anhydride (EPSA) with a poly amido-amine having two terminal -NH₂ groups, which can be illustrated as follows:

wherein x and y are each integers of from 0 to 10, with the proviso that the sum of x + y is at least 1, e.g., 1 to 20.
An example of the reaction of an amido-amine reactant with an ethylene copolymer substituted monocarboxylic acid material is the reaction of ethylene-propylene copolymer substituted propionic acid (EPA) with a poly amido-amine having two terminal -NH₂ groups, which can be illustrated as follows:

wherein x and y are each integers of from 0 to 10, with the proviso that the sum of x + y is at least 1, e.g., 1 to 20 and wherein Z¹ and Z² are the same or different and are each moieties of the formula:
It will be understood that the amido-amine reactant can be employed alone or in admixture with any of the above described amines, such as the polyalkylene polyamines, useful in preparing the amido-amine reactant.
Preferably, the ethylene copolymer substituted mono- or dicarboxylic acid material and amido-amine will be contacted for a time and under conditions sufficient to react substantially all of the primary nitrogens in the amido-amine reactant. The progress of this reaction can be followed by infra-red analysis.
This reaction can be conducted in a polar or non-polar solvent, e.g., xylene, toluene, benzene, and the like, and is preferably conducted in the presence of a mineral or synthetic lubricating oil.
In another, and generally preferred, embodiment of the instant invention, the grafted high molecular weight ethylene copolymer is reacted with the amido-amine and a carboxylic acid component or with the preformed reaction products, e.g., salts, amides, imides, of said amido-amine and carboxylic acid component.

CARBOXYLIC ACID COMPONENT

The carboxylic acid component includes: hydrocarbyl substituted dicarboxylic acid or anhydride, preferably succinic anhydride or acid, having 12 to 49 carbons, preferably 16 to 49 carbons in said hydrocarbyl group; long chain monocarboxylic acid of the formula RCOOH where R is a hydrocarbyl group of about 50 to about 400 carbons; and long chain hydrocarbyl substituted dicarboxylic acid or anhydride, preferably succinic anhydride or acid, having from about 50 to about 400 carbons in said hydrocarbyl group. The preferred carboxylic acid component is the long chain hydrocarbyl substituted dicarboxylic acid or anhydride, preferably succinic acid or anhydride, having from about 50 to about 400 carbon atoms in said hydrocarbyl group. Said hydrocarbyl groups are essentially aliphatic and include alkenyl and alkyl groups. The longer chain acids and anhydrides are preferred, particularly when the grafting reaction is carried out in lubricating oil.
The about C₅₀-C₄₀₀ hydrocarbyl subtituted dicarboxylic acid or anhydride includes the reaction product of the C₅₀-C₄₀₀ hydrocarbon polymer, generally a polyolefin, with (i) monounsaturated C₄ to C₁₀ dicarboxylic acid wherein (a) the carboxyl groups are vicinyl, i.e., located on adjacent carbon atoms, and (b) at least one, preferably both, of said adjacent carbon atoms are part of said monounsaturation; or with (ii) derivatives of (i) such as anhydrides of (i). Upon reaction with the hydrocarbon polymer, the monounsaturation of the dicarboxylic acid, anhydride, etc. becomes saturated. Thus for example, maleic anhydride becomes a hydrocarbyl substituted succinic anhydride.
Typically, from about 0.7 to about 4.0 (e.g., 0.8 to 2.6), preferably from about 1.0 to about 2.0, and most preferably from about 1.1 to about 1.7 moles of said unsaturated C₄ to C₁₀ dicarboxylic acid, anhydride or ester are charged to the reactor per mole of polyolefin charged.
Normally, not all of the polyolefin reacts with the unsaturated acid or derivative and the hydrocarbyl substituted dicarboxylic acid material will contain unreacted polyolefin. The unreacted polyolefin is typically not removed from the reaction mixture (because such removal is difficult and would be commercially infeasible) and the product mixture, stripped of any unreacted monounsaturated C₄ to C₁₀ dicarboxylic acid or anhydride, is employed as the carboxylic acid component.
Characterization of the average number of moles of dicarboxylic acid or anhydride, which have reacted per mole of polyolefin charged to the reaction (whether it has undergone reaction or not) is defined herein as functionality. Said functionality is based upon (i) determination of the saponification number of the resulting product mixture using potassium hydroxide; and (ii) the number average molecular weight of the polymer charged using techniques well known in the art. Functionality is defined solely with reference to the resulting product mixture. Although the amount of said reacted polyolefin contained in the resulting product mixture can be subsequently modified, i.e., increased or decreased by techniques known in the art, such modifications do not alter functionality as defined above. The term C₅₀-C₄₀₀ hydrocarbyl substituted dicarboxylic acid material is intended to refer to the product mixture whether it has undergone such modification or not.
Accordingly, the functionality of the C₅₀-C₄₀₀ hydrocarbyl substituted dicarboxylic acid material will be typically at least about 0.5, preferably at least about 0.8, and most preferably at least about 0.9 and will vary typically from about 0.5 to about 2.8 (e.g., 0.6 to 2), preferably from about 0.8 to about 1.4, and most preferably from about 0.9 to about 1.3.
Exemplary of such unsaturated dicarboxylic acids or anhydrides thereof are fumaric acid, itaconic acid, maleic acid, maleic anhydride, chloromaleic acid, chloromaleic anhydride, etc.
Preferred about C₅₀ to about C₄₀₀ olefin polymers for reaction with the unsaturated dicarboxylic acids or derivatives thereof are polymers comprising a major molar amount of C₂ to C₁₀, e.g., C₂ to C₅ monoolefin. Such olefins include ethylene, propylene, butylene, isobutylene, pentene, octene-1, styrene, etc. The polymers can be homopolymers such as polyisobutylene, as well as copolymers of two or more of such olefins such as copolymers of: ethylene and propylene; butylene and isobutylene; propylene and isobutylene; etc. Other copolymers include those in which a minor molar amount of the copolymer monomers, e.g., 1 to 10 mole %, is a C₄ to C₁₈ non-conjugated diolefin, e.g., a copolymer of isobutylene and butadiene; or a copolymer of ethylene, propylene and 1,4-hexadiene; etc.
In some cases, the olefin polymer may be completely saturated, for example an ethylene-propylene copolymer made by a Ziegler-Natta synthesis using hydrogen as a moderator to control molecular weight.
The olefin polymers used will usually have number average molecular weights within the range of about 700 and about 5,600, more usually between about 800 and about 3000. Particularly useful olefin polymers have number average molecular weights within the range of about 900 and about 2500 with approximately one terminal double bond per polymer chain. An especially useful starting material is polyisobutylene. The number average molecular weight for such polymers can be determined by several known techniques. A convenient method for such determination is by gel permeation chromatography (GPC) which additionally provides molecular weight distribution information, see W. W. Yau, J. J. Kirkland and D> D. Bly, "Modern Size Exclusion Liquid Chromatography", John WIley and Sons, New York, 1979.
Processes for reacting the about C₅₀ to about C₄₀₀ olefin polymer with the C₄₋₁₀ unsaturated dicarboxylic acid or anhydride are known in the art. For example, the olefin polymer and the dicarboxylic acid or derivative may be simply heated together as disclosed in U.S. Patents 3,361,673 and 3,401,118 to cause a thermal "ene" reaction to take place. Or, the olefin polymer can be first halogenated, for example, chlorinated or brominated to about 1 to 8 wt. %, preferably 3 to 7 wt. % chlorine, or bromine, based on the weight of polymer, by passing the chlorine or bromine through the polyolefin at a temperature of 60 to 250°C, e.g. 120 to 160°C, for about 0.5 to 10, preferably 1 to 7 hours. The halogenated polymer may then be reacted with sufficient unsaturated acid or derivative at 100 to 250°C, usually about 180 to 235°C, for about 0.5 to 10, e.g. 3 to 8 hours, so the product obtained will contain the desired number of moles of the unsaturated acid or derivative per mole of the halogenated polymer. Processes of this general type are taught in U.S. Patents 3,087,936; 3,172,892; 3,272,746 and others.
Alternatively, the olefin polymer, and the unsaturated acid or derivative are mixed and heated while adding chlorine to the hot material. Processes of this type are disclosed in U.S. Patents 3,215,707; 3,231,587; 3,912,764; 4,110,349; and in U.K. 1,550,219.
By the use of halogen, about 65 to 95 wt. % of the polyolefin, e.g. polyisobutylene will normally reacted with the dicarboxylic acid or derivative. Upon carrying out a thermal reaction without the use of halogen or a catalyst, then usually only about 50 to 75 wt. % of the polyisobutylene will react. Chlorination helps increased the reactivity.
Particularly preferred as the acid component is polyisobutenyl succinic anhydride.

PRE-REACTED AMIDO AMINE-CARBOXYLIC ACID COMPONENT

The aforesaid amido-amine and carboxylic acid component may be pre-reacted, with the acid being generally attached to the amido-amine through salt, imide, amide, or other linkages so that a primary or secondary amine group of the amido-amine is still available for reaction with the acid moieties of the grafted high molecular weight ethylene copolymer. A convenient source of these pre-reacted materials are the lubricating oil dispersant, provided they retain primary amine groups capable of further reaction with the grafted ethylene copolymer, described in EP-A-0319229 and EP-A-0368548.
The grafted high molecular weight ethylene copolymer is reacted with the amido-amine and carboxylic acid component or pre-reacted amido-amine-carboxylic acid component substantially as described hereinafore for the reaction of the grafted high molecular weight ethylene copolymer with the amido-amine. Thus, for example a reaction mixture containing the grafted high molecular weight ethylene copolymer, e.g., ethylene-propylene substituted succinic anhydride, and carboxylic acid component, e.g., polyisobutylene substituted succinic anhydride, is prepared by admixing these two reactants, and the amido-amine is then introduced into this reaction mixture and the reaction is carried out as described hereinafore. Alternatively, the carboxylic acid component and amido-amine may be added substantially simultaneously to a reaction mixture containing the grafted high molecular weight ethylene copolymer.
Generally, the amount of the carboxylic acid component utilized is an amount sufficient to provide 0.5 to about 4, preferably from 1 to 2 moles of said carboxylic acid component per molar amount of the carboxylic acid moieties present in the grafted ethylene copolymer. For example, with a grafted ethylene-propylene copolymer of about 40,000 M _n, i.e., a thickening efficiency of 2.1 g and averaging 4 succinic anhydride groups per molecule, 4 moles of polyisobutenyl succinic anhydride would preferably be used per mole of grafted copolymer. Generally, from 1 to 5, preferably from 1.5 to 3 moles of the combined carboxylic acid moiety content of the grafted ethylene copolymer and the carboxylic acid content are used per equivalent of amido-amine reactant, e.g., amine.
The compositions of matter of the instant invention, i.e., grafted ethylene copolymers reacted with the amido-amine, can be post-treated with a variety of materials, particularly acid materials, to inactivate any remaining primary amino groups of the adduct and thereby prevent crosslinking and gellation of the adduct. Thus, for example, the adduct may be post-reacted or post-treated with C₁ - C₃₀ monocarboxylic acids or anhydrides, preferably acetic anhydride, or unsubstituted or C₁ - C₃₀ monocarboxylic monocarboxylic acids or anhydrides, preferably acetic anhydride, or unsubstituted or C₁ to C₂₈ hydrocarbyl substituted dicarboxylic acid anhydrides as disclosed in U.S. Patent No. 4,137,185; and the sulfonic acids of U.S. Patent No. 4,144,181.
The multifunctional viscosity index improvers of this invention can be used alone or in admixture with other viscosity index improvers or dispersants. The other viscosity index improvers or viscosity modifiers are generally high molecular weight hydrocarbon polymers including polyesters. These other viscosity modifiers may also be derivatized, as by grafting with a carboxylic acid material of the type described hereinafore and thereafter reacting with a polyamine of the type described hereinafore as a polyol, to include other properties or functions, such as the addition of dispersancy properties. These oil soluble viscosity modifying polymers will generally have number average molecular weights of from 10³ to 10⁶, preferably 10⁴ to 10⁶, e.g., 20,000 to 250,000, as determined by gel permeation chromatography or osmometry.
Examples of suitable hydrocarbon polymers include homopolymers and copolymers of two or more monomers of C₂ to C₃₀, e.g. C₂ to C₈ olefins, including both alpha olefins and internal olefins, which may be straight or branched, aliphatic, aromatic, alkyl-aromatic, cycloaliphatic, etc. Frequently they will be of ethylene with C₃ to C₃₀ olefins, particularly preferred being the copolymers of ethylene and propylene. Other polymers can be used such as polyisobutylenes, homopolymers and copolymers of C₆ and higher alpha olefins, atactic polypropylene, hydrogenated polymers and copolymers and terpolymers of styrene, e.g. with isoprene and/or butadiene and hydrogenated derivatives thereof. The polymer may be degraded in molecular weight, for example by mastication, extrusion, oxidation or thermal degradation, and it may be oxidized and contain oxygen. Also included are derivatized polymers such as post-grafted interpolymers of ethylene-propylene with an active monomer such as maleic anhydride which may be further reacted with an alcohol, or amine, e.g. an alkylene polyamine or hydroxy amine, e.g. see U.S. Patent Nos. 4,089,794; 4,160,739; 4,137,185; or copolymers of ethylene and propylene reacted or grafted with nitrogen compounds such as shown in U.S. Patent Nos. 4,068,056; 4,068,058; 4,146,489 and 4,149,984.
The preferred hydrocarbon polymers are ethylene copolymers containing from 15 to 90 wt.% ethylene, preferably 30 to 80 wt.% of ethylene and 10 to 85 wt.%, preferably 20 to 70 wt.% of one or more C₃ to C₂₈, preferably C₃ to C₁₈, more preferably C₃ to C₈, alpha-olefins. While not essential, such copolymers preferably have a degree of crystallinity of less than 25 wt.%, as determined by X-ray and differential scanning calorimetry. Copolymers of ethylene and propylene are most preferred. Other alpha-olefins suitable in place of propylene to form the copolymer, or to be used in combination with ethylene and propylene, to form a terpolymer, tetrapolymer, etc. , include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc.; also branched chain alpha-olefins, such as 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methylpentene-1, 4,4-dimethyl-1-pentene, and 6-methylheptene-1, etc., and mixtures thereof.
Terpolymers, tetrapolymers, etc., of ethylene, said C₃₋₂₈ alpha-olefin, and a non-conjugated diolefin or mixtures of such diolefins may also be used. The amount of the non-conjugated diolefin generally ranges from about 0.5 to 20 mole percent, preferably from about 1 to about 7 mole percent, based on the total amount of ethylene and alpha-olefin present.
The polyester V.I. improvers are generally polymers of esters of ethylenically unsaturated C₃ to C₈ mono- and dicarboxylic acids such as methacrylic and acrylic acids, maleic acid, maleic anhydride, fumaric acid, etc.
Examples of unsaturated esters that may be used include those of aliphatic saturated mono alcohols of at least 1 carbon atom and preferably of from 12 to 20 carbon atoms, such as decyl acrylate, lauryl acrylate, stearyl acrylate, eicosanyl acrylate, docosanyl acrylate, decyl methacrylate, diamyl fumarate, lauryl methacrylate, cetyl methacrylate, stearyl methacrylate, and the like and mixtures thereof.
Other esters include the vinyl alcohol esters of C₂ to C₂₂ fatty or mono carboxylic acids, preferably saturated such as vinyl acetate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, and the like and mixtures thereof. Copolymers of vinyl alcohol esters with unsaturated acid esters such as the copolymer of vinyl acetate with dialkyl fumarates, can also be used.
The esters may be copolymerized with still other unsaturated monomers such as olefins, e.g. 0.2 to 5 moles of C₂ - C₂₀ aliphatic or aromatic olefin per mole of unsaturated ester, or per mole of unsaturated acid or anhydride followed by esterification. For example, copolymers of styrene with maleic anhydride esterified with alcohols and amines are known, e.g., see U.S. Patent 3,702,300.
Such ester polymers may be grafted with, or the ester copolymerized with, polymerizable unsaturated nitrogen-containing monomers to impart dispersancy to the V.I. improvers. Examples of suitable unsaturated nitrogen-containing monomers include those containing 4 to 20 carbon atoms such as amino substituted olefins as p-(beta-diethylaminoethyl)styrene; basic nitrogen-containing heterocycles carrying a polymerizable ethylenically unsaturated substituent, e.g. the vinyl pyridines and the vinyl alkyl pyridines such as 2-vinyl-5-ethyl pyridine, 2-methyl-5-vinyl pyridine, 2-vinyl-pyridine, 4-vinyl-pyridine, 3-vinyl-pyridine, 3-methyl-5-vinyl-pyridine, 4-methyl-2-vinyl-pyridine, 4-ethyl-2-vinyl-pyridine and 2-butyl-1-5-vinyl-pyridine and the like.
N-vinyl lactams are also suitable, e.g. N-vinyl pyrrolidones or N-vinyl piperidones.
The vinyl pyrrolidones are preferred and are exemplified by N-vinyl pyrrolidone, N-(1-methylvinyl) pyrrolidone, N-vinyl-5-methyl pyrrolidone, N-vinyl-3, 3-dimethylpyrrolidone, N-vinyl-5-ethyl pyrrolidone, etc.
Dispersants maintain oil insolubles, resulting from oxidation during use, in suspension in the fluid thus preventing sludge flocculation and precipitation as deposition on metal parts. Suitable dispersants include alkyl succinimides, the reaction product of oil-soluble polyisobutylene succinic anhydride with polyamines such as tetraethylene pentamine, and borated salts thereof. Such dispersants are disclosed, inter alia, in Belgium Patent No. 658,236 and U.S. Patent No. 3,272,746.
Other dispersants include the esters derived from long chain hydrocarbon substituted dicarboxylic acid material and hydroxy compounds such as monohydric and polyhydric alcohols or aromatic compounds such as phenols and naphthols, etc. The polyhydric alcohols are the most preferred hydroxy compound and preferably contain from 2 to about 10 hydroxy radicals, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and other alkylene glycols in which the alkylene radical contains from 2 to about 8 carbon atoms. Other useful polyhydric alcohols include glycerol, mono-oleate of glycerol, monostearate of glycerol, monomethyl ether of glycerol, pentaerythritol, dipentaerythritol, and mixtures thereof.
The ester dispersant may also be derived from unsaturated alcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexane-3-ol, and oleyl alcohol. Still other classes of the alcohols capable of yielding the esters of this invention comprise the ether-alcohols and amino-alcohols including, for example, the oxy-alkylene, oxy-arylene-, amino-alkylene-, and amino-arylene-substituted alcohols having one or more oxy-alkylene, amino-alkylene or amino-arylene oxy-arylene radicals. They are exemplified by Cellosolve, Carbitol, N,N,N',N'-tetrahydroxy-trimethylene di-amine, and ether-alcohols having up to about 150 oxy-alkylene radicals in which the alkylene radical contains from 1 to about 8 carbon atoms.
The ester dispersant may be di-esters of dicarboxylic acids (e.g., succinic acid or anhydride) or acidic esters, i.e., partially esterified succinic acids; as well as partially esterified polyhydric alcohols or phenols, i.e., esters having free alcohols or phenolic hydroxyl radicals. Mixtures of the above illustrated esters likewise are contemplated within the scope of this invention.
The ester dispersant may be prepared by one of several known methods as illustrated for example in U.S. Patent 3,381,022. The ester dispersants may also be borated, similar to the nitrogen containing dispersants.
Hydroxyamines which can be reacted with the polymer-substituted monocarboxylic acid materials to form dispersants include 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, p-(beta-hydroxyethyl)-aniline, 2-amino-1-propanol, 3-amino-1-propanol, 2-amino-2-methyl-1, 3-propane-diol, 2-amino-2-ethyl-1, 3-propanediol, N-(beta-hydroxy-propyl)-N'-(beta-aminoethyl)-piperazine, tris(hydroxymethyl) amino-methane (also known as trismethylolaminomethane), 2-amino-1-butanol, ethanolamine, beta-(beta-hydroxyethoxy)ethylamine, and the like. Mixtures of these or similar amines can also be employed. The above description of nucleophilic reactants suitable for reaction with the polymer-substituted monocarboxylic acid materials includes amines, alcohols, and compounds of mixed amine and hydroxy containing reactive functional groups, i.e., amino-alcohols.
The tris(hydroxymethyl) amino methane (THAM) can be reacted with the aforesaid acid materials to form amides, imides or ester type additives as taught by U.K. 984,409, or to form oxazoline compounds and borated oxazoline compounds as described, for example, in U.S. 4,102,798; 4,116,876 and 4,113,639.
The multifunctional viscosity index improvers of the present invention can be incorporated into a lubricating oil in any convenient way. Thus, they can be added directly to the oil by dispersing or dissolving the same in the oil at the desired level of concentration of the multifunctional viscosity index improvers. Such blending into the additional lube oil can occur at room temperature or elevated temperatures. Alternatively, the multifunctional viscosity index improvers can be blended with a suitable oil-soluble solvent and base oil to form a concentrate, and then blending the concentrate with a lubricating oil basestock to obtain the final formulation. Such multifunctional viscosity index improver concentrates will typically contain (on an active ingredient (A.I.) basis) from 3 to 45 wt.%, and preferably from 10 to 35 wt.%, multifunctional viscosity index improver additive, and typically from 30 to 90 wt.%, preferably from 40 to 60 wt.%, base oil, based on the concentrate weight.
The lubricating oil basestock for the multifunctional viscosity index improver typically is adapted to perform a selected function by the incorporation of additional additives therein to form lubricating oil compositions (i.e., formulations).
The amounts of the multifunctional viscosity improver additives of the instant invention which are incorporated into an oleaginous composition, e.g., lubricating oil, is an amount which is effective to improve the viscometric properties, e.g., viscosity index, of said oleaginous composition and impart dispersancy thereto, i.e., a viscosity improving and dispersant effective amount. Generally, this amount is from 0.01 to about 20, preferably from 0.1 to 10, and more preferably from 0.2 to 5 weight percent, based on the weight of the oleaginous composition.
The oleaginous composition into which the multifunctional viscosity improvers or modifiers of the instant invention are incorporated or added include lubricating oil compositions, e.g., automatic transmission fluids, heavy duty oils suitable for gasoline and diesel engines, etc.
The multifunctional viscosity improvers of this invention may be added to the oleaginous composition in the form of an oil concentrate. Typically such oil concentrate contains from 5 wt.% up to 49 wt.%, preferably 7 to 25 wt.%, of the multifunctional viscosity improver in oil, e.g., mineral lubricating oil.
The fully formulated oil compositions, or the oil concentrate, may optionally contain other conventional additives such as pour point depressants, antiwear agents, antioxidants, other viscosity index improvers, dispersants, corrosion inhibitors, anti-foaming agents, detergents, rust inhibitors, friction modifiers, and the like.
Corrosion inhibitors, also known as anti-corrosive agents, reduce the degradation of the metallic parts contacted by the lubricating oil composition. Illustrative of corrosion inhibitors are phosphosulfurized hydrocarbons and the products obtained by reaction of a phosphosulfurized hydrocarbon with an alkaline earth metal oxide or hydroxide, preferably in the presence of an alkylated phenol or of an alkylphenol thioester, and also preferably in the presence of carbon dioxide.
Other oxidation inhibitors or antioxidants useful in this invention comprise oil-soluble copper compounds. The copper may be blended into the oil as any suitable oil soluble copper compound. By oil soluble it is meant that the compound is oil soluble under normal blending conditions in the oil or additive package. The copper compound may be in the cuprous or cupric form. The copper may be in the form of the copper dihydrocarbyl thio- or dithio-phosphates. Alternatively, the copper may be added as the copper salt of a synthetic or natural carboxylic acid. Examples of same thus include C₁₀ to C₁₈ fatty acids, such as stearic or palmitic acid, but unsaturated acids such as oleic or branched carboxylic acids such as napthenic acids of molecular weights of from about 200 to 500, or synthetic carboxylic acids, are preferred, because of the improved handling and solubility properties of the resulting copper carboxylates. Also useful are oil-soluble copper dithiocarbamates of the general formula (RR,NCSS)nCu (where n is 1 or 2 and R and R, are the same or different hydrocarbyl radicals containing from 1 to 18, and preferably 2 to 12, carbon atoms, and including radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R and R, groups are alkyl groups of from 2 to 8 carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order to obtain oil solubility, the total number of carbon atoms (i.e., R and R,) will generally be about 5 or greater. Copper sulphonates, phenates, and acetylacetonates may also be used.
Exemplary of useful copper compounds are copper CuI and/or CuII salts of alkenyl succinic acids or anhydrides. The salts themselves may be basic, neutral or acidic. They may be formed by reacting (a) polyalkylene succinimides (having polymer groups of M _n of 700 to 5,000) derived from polyalkylene-polyamines, which have at least one free carboxylic acid group, with (b) a reactive metal compound. Suitable reactive metal compounds include those such as cupric or cuprous hydroxides, oxides, acetates, borates, and carbonates or basic copper carbonate.
Examples of these metal salts are Cu salts of polyisobutenyl succinic anhydride, and Cu salts of polyisobutenyl succinic acid. Preferably, the selected metal employed is its divalent form, e.g., Cu+2. The preferred substrates are polyalkenyl succinic acids in which the alkenyl group has a molecular weight greater than about 700. The alkenyl group desirably has a M_n from about 900 to 1,400, and up to 2,500, with a M_n of about 950 being most preferred. Especially preferred is polyisobutylene succinic anhydride or acid. These materials may desirably be dissolved in a solvent, such as a mineral oil, and heated in the presence of a water solution (or slurry) of the metal bearing material. Heating may take place between 70. and about 200°C. Temperatures of 110°C to 140°C are entirely adequate. It may be necessary, depending upon the salt produced, not to allow the reaction to remain at a temperature above about 140°C for an extended period of time, e.g., longer than 5 hours, or decomposition of the salt may occur.
The copper antioxidants (e.g., Cu-polyisobutenyl succinic anhydride, Cu-oleate, or mixtures thereof) will be generally employed in an amount of from about 50 to 500 ppm by weight of the metal, in the final lubricating or fuel composition.
Friction modifiers serve to impart the proper friction characteristics to lubricating oil compositions such as automatic transmission fluids.
Representative examples of suitable friction modifiers are found in U.S. Patent No. 3,933,659 which discloses fatty acid esters and amides; U.S. Patent No. 4,176,074 which describes molybdenum complexes of polyisobutenyl succinic anhydride-amino alkanols; U.S. Patent No. 4,105,571 which discloses glycerol esters of dimerized fatty acids; U.S. Patent No. 3,779,928 which discloses alkane phosphonic acid salts; U.S. Patent No. 3,778,375 which discloses reaction products of a phosphonate with an oleamide; U.S. Patent No. 3,852,205 which discloses S-carboxyalkylene hydrocarbyl succinimide, S-carboxyalkylene hydrocarbyl succinamic acid and mixtures thereof; U.S. Patent No. 3,879,306 which discloses N(hydroxyalkyl)alkenyl-succinamic acids or succinimides; U.S. Patent No. 3,932,290 which discloses reaction products of di- (lower alkyl) phosphites and epoxides; and U.S. Patent No. 4,028,258 which discloses the alkylene oxide adduct of phosphosulfurized N-(hydroxyalkyl) alkenyl succinimides. The most preferred friction modifiers are succinate esters, or metal salts thereof, of hydrocarbyl substituted succinic acids or anhydrides and thiobis-alkanols such as described in U.S. Patent No. 4,344,853.
Pour point depressants, otherwise known as lube oil flow improvers, lower the temperature at which the fluid will flow or can be poured. Such additives are well known. Typically of those additives which usefully optimize the low temperature fluidity of the fluid are C₈-C₁₈ dialkylfumarate vinyl acetate copolymers, polymethacrylates, and wax naphthalene. Foam control can be provided by an antifoamant of the polysiloxane type, e.g., silicone oil and polydimethyl siloxane.
Anti-wear agents, as their name implies, reduce wear of metal parts. Representatives of conventional antiwear agents are zinc dialkyldithiophosphate and zinc diaryldithiosphate.
Detergents and metal rust inhibitors include the metal salts of sulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkyl salicylates, naphthenates and other oil soluble mono- and di-carboxylic acids. Highly basic (viz, overbased) metal salts, such as highly basic alkaline earth metal sulfonates (especially Ca and Mg salts) are frequently used as detergents. Representative examples of such materials, and their methods of preparation, are found in EP-A-0208560.
Some of these numerous additives can provide a multiplicity of effects, e.g., a dispersant-oxidation inhibitor. This approach is well known and need not be further elaborated herein.
Compositions when containing these conventional additives are typically blended into the base oil in amounts which are effective to provide their normal attendant function. Representative effective amounts of such additives are illustrated as follows:
When other additives are employed, it may be desirable, although not necessary, to prepare additive concentrates comprising concentrated solutions or dispersions of the multifunctional viscosity improver (in concentrate amounts hereinabove described), together with one or more of said other additives (said concentrate when constituting an additive mixture being referred to here in as an additive package) whereby several additives can be added simultaneously to the base oil to form the lubricating oil composition. Dissolution of the additive concentrate into the lubricating oil may be facilitated by solvents and by mixing accompanied with mild heating, but this is not essential. The concentrate or additive-package will typically be formulated to contain the dispersant additive and optional additional additives in proper amounts to provide the desired concentration in the final formulation when the additive-package is combined with a predetermined amount of base lubricant. Thus, the products of the present invention can be added to small amounts of base oil or other compatible solvents along with other desirable additives to form additive-packages containing active ingredients in collective amounts of typically from 2.5 to 80%, and preferably from 5 to 60%, and most preferably from 8 to 49% by weight additives in the appropriate proportions with the remainder being base oil.
The final formulations may employ typically about 10 wt. % of the additive-package with the remainder being base oil.
All of said weight percents expressed herein are based on active ingredient (a.i.) content of the additive, and/or upon the total weight of any additive-package, or formulation which will be the sum of the a.i. weight of each additive plus the weight of total oil or diluent.
The instant compositions of matter useful as multifunctional viscosity modifiers or improvers are oil-soluble, dissolvable in oil with the aid of a suitable solvent, or are stably dispersible materials. Oil-soluble, dissolvable, or stably dispersible as that terminology is used herein does not necessarily indicate that the materials are soluble, dissolvable, miscible, or capable of being suspended in oil in all proportions. It does mean, however, that the additives, for instance, are soluble or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incorporation of other additives may also permit incorporation of higher levels of a particular copolymer hereof, if desired.
The following Examples further illustrate the instant invention. They are presented by way of illustration and not limitation. Unless otherwise indicated, all parts and percentages are on a weight basis.
The following examples illustrate the preparation of amido-amines of the instant invention.

EXAMPLE 1

Into a reactor vessel are charged 148 grams (2 moles) of 1,3-propane diamine and stirred at room temperature under a nitrogen atmosphere. 86 grams (one mole) of methyl acrylate are slowly introduced into the reactor vessel while keeping the resulting reaction mixture below 50°C. After the methyl acrylate addition is complete the reaction mixture is heated at 80°C until infrared analysis shows the absence of the ester bond. The reaction mixture is then stripped at 80°C for one hour to distill off the methanol byproduct. Analysis of the resulting amido-amine product indicates 9.93 meq. of primary nitrogen per gram of sample and 27.64% nitrogen.

EXAMPLE 2

The procedure of Example 1 is repeated except that the 148 grams of 1,3-propane diamine are replaced with 203 grams (2 moles) of diethylene triamine. Analysis of the resulting amido-amine product indicates 4.48 meq. of primary nitrogen per gram of sample and 25.85% nitrogen.

EXAMPLE 3

The procedure of Example 1 is repeated except that the 148 grams of 1,3-propane diamine are replaced with 292 grams (2 moles) of triethylene triamine. Analysis of the resulting amido-amine product indicates 3.67 meq. of primary nitrogen per gram of sample and 26.76% nitrogen.

EXAMPLE 4

The procedure of Example 1 is repeated except that the 148 grams of 1,3-propane diamine are replaced with 378 grams (2 moles) of tetraethylene pentamine. Analysis of the resulting amido-amine product indicates 4.39 meq. of primary nitrogen per gram of sample and 28.3% nitrogen.
The following Examples illustrate the preparation of the nitrogen containing carboxylic acid material grafted ethylene propylene copolymers of the instant invention.

EXAMPLE 5

Into a reactor vessel are charged 200 grams of a 20 wt. % oil solution of succinic-anhydride grafted ethylene-propylene copolymer (containing about 43 wt.% ethylene and 57% wt.% propylene, the ethylene-propylene backbone having a M _n of about 80,000, and having a thickening efficiency of about 1.2), 21.3 grams of polyisobutenyl succinic anhydride (having a succinic anhydride to polyisobutenyl mole ratio of 1.04, a polyisobutylene M _n of about 960, ASTM Saponification Number of 112, and 90 wt.% active ingredient, i.e., polyisobutenyl succinic anhydride, the remainder being primarily unreacted polyisobutylene), and 130 grams of S130N mineral oil. The reactor vessel is blanketed with nitrogen and heated to 175°C for one-half hour. To this reactor vessel are then added 4.12 grams of amido-amine prepared in accordance with the procedure of Example 1. The reaction mixture is nitrogen stripped for 3 hours at 175°C. At the end of this period the reaction mixture is cooled to 100°C and is discharged from the reaction vessel.

EXAMPLE 6

The procedure of Example 5 is repeated except that the 4.12 grams of the amido-amine prepared in accordance with the procedure of Example 1 are replaced with 9.02 grams of amido-amine prepared in accordance with the procedure of Example 2.

EXAMPLE 7

The procedure of Example 5 is repeated except that the 4.12 grams of the amido-amine prepared in accordance with the procedure of Example 1 are replaced with 11.0 grams of amido-amine prepared in accordance with the procedure of Example 3.

EXAMPLE 8

The procedure of Example 5 is repeated except that the 4.12 grams of the amido-amine prepared in accordance with the procedure of Example 1 are replaced with 9.2 grams of amido-amine prepared in accordance with the procedure of Example 4.
Thickening efficiency (T.E.) is defined as the ratio of the weight percent of a polyisobutylene (sold as an oil solution by Exxon Chemical Company as Paratone N), having a Staudinger molecular weight of 20,000, required to thicken a solvent-extracted neutral mineral lubricating oil, having a viscosity of 32 x 10² cm/sec (150 SUS) at 37.8°C, a viscosity index of 105 and an ASTM pour point of 0°F. (Solvent 150 Neutral) to a viscosity of 12.4 x 10² cm²/sec (centistokes) at 98.9°C to the weight percent of a test copolymer required to thicken the same oil to the same viscosity at the same temperature. For linear polymers of a given ethylene content, the thickening efficiency is approximately proportional to the 0.75 power of the weight-average molecular weight.

Claims

An oil soluble composition useful as a multifunctional viscosity improver additive for oleaginous composition comprising adduct of:
(A) high molecular weight ethylene copolymer substituted carboxylic acid material comprising reaction product of (i) ethylene copolymer having a number average molecular weight of at least 15,000, and (ii) monounsaturated carboxylic acid material; and

(B) amido-amine or thioamido-amine comprising reaction product of (i) polyamine, and (ii) alpha, beta-unsaturated compound represented by the formula
wherein X is oxygen or sulfur, Y is -OR⁴, -5R⁴, or
and R¹, R², R³, R⁴ and R⁵ are independently selected from hydrogen, hydrocarbyl, and substituted hydrocarbyl.
The composition according to claim 1 wherein said ethylene copolymer (A)(i) comprises copolymer of ethylene and at least one C₃ to C₂₈ alpha-olefin.
The composition according to claim 2 wherein said C₃ to C₂₈ alpha-olefin is propylene.
The composition according to any of claims 1 to 3 wherein said monounsaturated carboxylic acid material (A)(ii) is selected from the group consisting of C₄ to C₁₀ monounsaturated dicarboxylic acid material, C₃ to C₁₀ monounsaturated monocarboxylic acid material, and mixtures thereof.
The composition according to claim 4 wherein (A) (ii) is selected from maleic anhydride, maleic acid, and mixtures thereof.
The composition according to claim 4 wherein (A)(ii) is selected from acrylic acid, acrylic ester, methacrylic acid, methacrylic acid, and mixtures thereof.
The composition according to claim 1 wherein said high molecular weight ethylene copolymer substituted carboxylic acid material comprises at least one of ethylene-propylene copolymer substituted with succinic anhydride and ethylene-propylene copolymer substituted with succinic acid.
The composition according to claim 1 wherein said high molecular weight ethylene copolymer substituted carboxylic acid material comprises ethylene- propylene copolymer substituted with propionic acid.
The composition according to any of claims 1 to 8 wherein said polyamine (B)(i) comprises polyamines containing from 2 to 60 carbon atoms and from 2 to 12 nitrogen atoms per molecule.
The composition according to claim 9 wherein said polyamine (B)(i)comprises alkylenepolyamine or polyalkylenepolyamine wherein each alkylene group contains 2 to 6 carbons and said alkylenepolyamine or polyalkylenepolyamine contains from 2 to 5 nitrogen atoms per molecule.
The composition according to claim 10 wherein said polyamine (B)(i) comprises ethylenepolyamine, propylenepolyamine, polyethylene- polyamine, or polypropylenepolyamine.
The composition according to any of claims 1 to 11 wherein said polyamine (B)(i) contains an average of at least 2 primary amine groups per molecule.
The composition according to any of claims 1 to 12 wherein (B)(ii) comprises at least one of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate.
The composition according to claim 12 and 13 wherein said polyamine (B)(i) contains from 2 to 60 carbon atoms and from 2 to 12 nitrogen atoms, and said alpha, beta-unsaturated compound (B)(ii) comprising C₁ to C₄ alkyl esters of acrylic or methacrylic acid.
The composition according to any of claims 1 to 14 wherein from 3 to 5 equivalents of said polyamine, based on said primary amine content thereof, are reacted per mole of said alpha, beta-unsaturated compound (B)(ii).
The composition according to any of claims 1 to 15 wherein x of (B)I(ii) is oxygen and the amido amine contains an average of from 1 to 3 amido groups per molecule.
The composition according to any of claims 1 to 15 wherein X of (B)(ii) is sulfur and the thioamido-amine contains an average of from 1 to 3 thioamido groups per molecule.
The composition according to any of claims 1 to 9 wherein said polyamine (II)(B)(i) comprises alkylenepolyamine or polyalkylenepolyamine wherein each alkylene group contains 2 to 6 carbons and said alkylenepolyamine or polyalkylenepolyamine contains from 5 to 9 nitrogen atoms per molecule.
The composition according to any of claims 1 to 18 wherein said adduct comprises (A), (B) and (C) C₁₂-C₄₀₀ hydrocarbyl substituted dicarboxylic acid or anhydride, or C₅₀-C₄₀₀ hydrocarbyl substituted monocarboxylic acid.
The composition according to claim 19 wherein said (C) is C₁₂-C₄₀₀ hydrocarbyl substituted succinic acid or anhydride.
The composition according to claim 20 wherein component (C) is C₁₂₋₄₀₀ polyisobutenyl succinic anhydride.
The composition according to claim 20 wherein component (C) is C₅₀₋₄₀₀ polyisobutenyl succinic anhydride.
An oleaginous composition exhibiting improved viscosimetric properties and dispersancy comprising:
(I) oleaginous material, and

(II) as a multifunctional viscosity improving and dispersant additive, a composition according to any of claims 1 to 22.
The composition according to claim 24 in which (I) is a lubricating oil.
The composition according to claim 23 in the form of an oil concentrate containing from 5 to 49 wt.% of (II).
The composition according to claim 23 in which (I) is a fully formulated lubricating oil composition.
The composition according to claim 26 containing from 0.01 to 20 wt.% of (II).
The composition according to claim 27 containing from 0.1 to 10 wt.% of (II).
The composition according to claim 27 containing from 0.2 to 5 wt.% of (II).
A process for producing a composition useful as a multifunctional viscosity improver oil additive which comprises reacting:
(A) high molecular weight ethylene copolymer substituted carboxylic acid material comprising the reaction product of
(i) an ethylene copolymer having a number average molecular weight M_n of at least 15,000 and

(ii) monounsaturated carboxylic acid material;

(B) an amido-amine or thioamido-amine compound containing at least one primary amino group comprising the reaction product of
(i) at least one polyamine and

(ii) an alpha, beta-unsaturated compound of the formula:
wherein X is sulfur or oxygen, Y is -OR⁴, -SR⁴, or -NR⁴(R⁵), and R¹, R², R³, R⁴ and R⁵ are the same or different and are independently selected from hydrogen and substituted or unsubstituted hydrocarbyl radicals; wherein said amine compound (B) is introduced into a solution containing said polymeric acid material (A) and heated therewith at a temperature from 100°C to 250°C for a period from 1 to 10 hours, such that at least a portion of said primary amino groups of said amine compound (B) react with at least a portion of the carboxyl groups of said polymeric acid material (A).
A process according to claim 30 wherein said polymeric acid material (A) is reacted with said amine compound (B) and a carboxylic acid component (C), or with the preformed reaction product of (B) and (C).
A process according to claim 31 wherein said component (C) is a C₁₂₋₄₀₀ hydrocarbly substituted dicarboxylic acid or anhydride.
A process according to claim 32 wherein said component (C) is a C₁₂₋₄₀₀ hydrocarbyl substituted succinic acid or anhydride.
A process according to claim 33 wherein said component (C) is a C₁₂₋₄₀₀ polyisobutenyl succinic acid or anhydride.
A process according to any one of claims 30 to 34 wherein said carboxylic acid material (A)(ii) is a C₄₋₁₀ dicarboxylic acid or anhydride.
A process according to claim 35 wherein said C₄₋₁₀ acid or anhydride is succinic anhydride.
A process according to any of claims 30 to 36 wherein said ethylene copolymer (A)(i) is an ethylene-propylene copolymer.
A process according to any one of claims 30 to 34 wherein said carboxylic acid material (A)(ii) is a C₃₋₁₀ monocarboxylic acid or anhydride.
A process according to claim 38 wherein said ethylene copolymer (A)(i) is an ethylene-propylene copolymer.
A process according to any one of claims 30 to 39 wherein said polyamine (B)(i) comprises an alkylene polyamine or polyalkylenepolyamine having 2 to 5 nitrogen atoms per molecule and 2 to 6 carbon atoms in each alkylene group.
A process according to claim 40 wherein X in component (B)(ii) is oxygen.