DE68918728T2 - Demulsified lubricating oils. - Google Patents

Abstract

In accordance with one aspect, the present invention is directed to a lubricating oil additive mixture comprising (A) a lubricating oil dispersant additive comprising at least one of (1) ashless dispersants and/or (2) polymeric viscosity index improver dispersants, and (B) a demulsifier additive comprising the reaction product of an alkylene oxide and an adduct obtained by reacting a bis-epoxide with a polyhydric alcohol. In a preferred embodiment, the lubricating oil additive mixtures further comprises (C) a compatibilizer additive for the demulsifier, which comprises a glycol ester or a hydroxyamide derivative of a carboxylic acid having a total of from 24 to 90 carbon atoms and at least one carboxylic group per molecule, for enhanced solubility, viz. stability, of the demulsifier in the oil solutions containing such dispersants.

Description

This invention relates to oily compositions containing high molecular weight ashless dispersants and demulsifier additives having improved demulsifying capabilities. Such concentrates are useful in oily compositions including fuel and lubricating oil compositions.

Sequence IID is one of the established ASTM tests that set the current standard of crankcase lubricants for gasoline engines (American Society for Testing and Materials, Special Technical Publication 315H, Part 1, September 15, 1979). This test, designed to evaluate the rust-inhibiting properties of the lubricant, creates an environment that leads to rust formation, in part by trapping water vapor from combustion gases in the crankcase using a cooler at the crankcase ventilation outlet.

A byproduct of the humid IID environment is the presence of conditions highly conducive to emulsion formation. Although emulsions are not necessarily a concern in themselves, the cooler tubes can become partially clogged by the emulsion, resulting in a loss of pressure across the cooler and a resulting buildup of pressure in the crankcase. Engine manufacturers are concerned that oils that form emulsions also tend to clog PCV valves or other lines associated with the crankcase ventilation system in the field and coat other engine surfaces such as the rocker covers, valve covers, etc. with emulsion. This concern is particularly relevant to internal combustion engines that do not use fresh air purge of the crankcase. In such cases, the lack of fresh air purge can cause water to build up in the crankcase vapors. In some engines, crankcase vapors are routed to an external separator designed to separate entrained liquids and vapors. The separated liquids should continuously flow back into the crankcase and the gases passing through the separator should be mixed with air and/or fuel (or mixtures thereof) are combined to be introduced into the cylinder of the engine for combustion. The presence of an emulsion in the crankcase and in the entrained vapours passed to the separator will result in clogging or at least a build-up of the effective pressure drop in the separator, reducing its effectiveness. This can, in severe cases, lead to an unplanned increase in crankcase pressure beyond design limits, which can cause oil blowout through crankcase seals and other problems. In cold climates and during short trips or low speed conditions, the above problems may be more pronounced.

It is necessary that crankcase lubricants for internal combustion engines suspend solids resulting from, for example, the inevitable oxidation of oil components during engine operation in order to minimize both the level of deposits (e.g. varnish) on the engine components and the formation of sludge. Since modern engines operate at high temperatures as a result of reduced engine sizes and high power requirements, modern crankcase lubricant formulations require the use of high levels of dispersibility (provided, for example, by using high molecular weight dispersants or increased levels of lower molecular weight dispersants) and the use of other potent engine components in order to minimize the adverse effects on the engine of oxidation of the lubricant during use.

For example, stricter crankcase limits have been proposed in the Sequence IID test to prevent emulsion formation in modern lubricating oil formulations.

Unfortunately, the critical components necessary to maintain engine cleanliness and control deposit formation in modern lubricating oil formulations, many dispersants and multifunctional viscosity modifiers, can be highly potent emulsifiers.

To date, a wide variety of lubricating oil demulsifiers have been proposed.

US-A-3 509 052 discloses lubricating oil demulsifiers comprising certain alkylphenoxypoly(ethyleneoxy)ethyl mono- and diesters of phosphoric acid, polyoxyethylated amines, amides and quaternary salts and polyoxyalkylene polyols and esters of such polyoxyalkylene polyols with lauric acid, stearic acid, succinic acid and alkyl- or alkenyl-substituted succinic acids (up to 20 carbon atoms in the alkyl or alkenyl group).

US-A-3 511 882 relates to petroleum demulsifiers for crude oil prepared by adding a higher alkylene oxide, e.g. butylene oxide or propylene oxide, to a monovalent, divalent or trivalent compound (e.g. propylene glycol). Ethylene oxide is then added to the first adduct to form an oxyethylated adduct in which the proportion of primary hydroxyl groups to secondary hydroxyl groups is controlled. The oxyethylated adduct is then reacted with an epoxide of a polyphenol, preferably a diglycidyl ether of bisphenol-A. Demulsification is accomplished by mixing the demulsifiers with the crude oil emulsions in a ratio of about one part demulsifier to 2,000 to 50,000 parts of emulsion, after which the emulsion is left in a relatively quiescent state while separation of the oil and water takes place. It is disclosed that these demulsifiers can be used in combination with other demulsifiers from classes such as the petroleum sulfonate type, of which naphthene sulfonic acid is an example, the modified fatty acid type, and the amine modified oxyalkylated phenol-formaldehyde type.

US-A-2 996 551 describes demulsifiers for petroleum emulsions which generally include the reaction product of an aliphatic diepoxide with the adduct of polypropylene and a polyol. No results of its use in combination with other lubricant additives are given.

Crude oil demulsifiers have been used to break oil emulsions from crude petroleum (e.g. in deep well applications) and include adducts which are formed by reacting diglycidyl ether of bisphenol A with polypropylene glycol and its propoxylated derivatives.

However, the environment in which demulsifiers are used to break crude oil emulsions and the manner in which the quiescent state for emulsion phase separation is allowed to take place is quite different from the dynamic flow and shear conditions in the environment in which crankcase lubricating oils are used in internal combustion engines and also contrasts with the variety of other lubricating oil additives used in crankcase lubricant compositions. Primarily, the action of the demulsifiers can counteract the ashless dispersants in crankcase lubricating oils.

The modern trend towards the use of higher molecular weight ashless dispersants in such formulations and in additive concentrates has therefore made the search for more potent demulsifier additives very difficult. In addition, the frequent co-use with metal detergents with a high total base number in such formulations and concentrates requires that the demulsifier be compatible with these compositions, i.e. the demulsifier should not adversely affect the shelf life of these products.

Heretofore, many lubricants and fuels have contained compounds known as friction modifiers (also referred to as "lubricity additives") which act to reduce the friction of internal engine parts and thereby increase fuel economy. US-A-3,429,817 relates to improving the lubricity and load-carrying capacity of a synthetic ester lubricating oil by adding an ester formed by reacting about 2 moles of C2 to C5 glycol with about 1 mole of C36 dicarboxylic acid dimer of a C18 unsaturated fatty acid (e.g., linoleic acid or oleic acid). US-A-3,273,981 relates to fuels and lubricating oil containing a mixture of dimer acids and partial esters of polyhydric alcohol as a lubricating additive. US-A-4 459 223 relates to friction reducing additives for lubricating oil which comprise the reaction product of a dimer carboxylic acid (e.g. linoleic acid dimers) and a polyhydric Alcohol having at least 3 hydroxyl groups. US-A-4 479 883 relates to lubricating oil compositions having a relatively low phosphorus level and improved friction reducing additives by using a mixture of a glycol or glycerol ester of a polycarboxylic acid (e.g. linoleic acid dimers) with Mo, Zn or Sb dithiocarbamates. US-A-4 557 846 relates to friction reducing additives for lubricating oil comprising oil-soluble hydroxyamide compounds prepared by condensing a dimeric carboxylic acid (e.g. linoleic acid dimers) with a hydroxyamine. US-A-4,617,026 relates to friction modifier additives for fuels comprising hydroxyl-containing esters of a C₁₂ to C₃₀ monocarboxylic acid and a glycol or trihydric alcohol, wherein the glycol may comprise polyalkylene glycols having from 2 to 100 repeating oxyalkylene units. US-A-4,683,069 relates to fuel economy additives for lubricating oil comprising partial esters of glycerin and C₁₆ to C₁₈ fatty acids.

The instability and therefore the need for stabilization of compositions containing polycarboxylic acid glycol esters, ashless dispersants and certain metal lubricating oil additives has been noted in the prior art. US-A-4,105,571 relates to storage stable lubricant compositions with improved antifriction and antiwear properties containing a zinc dihydrocarbyl dithiophosphate, an ester of a polycarboxylic acid and a glycol, and a high molecular weight ashless dispersant, wherein either the zinc or ester component or both are predispersed with the ashless dispersant before being added to the lubricant composition. The friction modifier esters are disclosed to include linoleic acid dimers esterified with glycol such as diethylene glycol.

US-A-4 388 201 discloses lubricating oil compositions containing such polycarboxylic acid glycol friction modifier esters in combination with borated or non-borated alkenyl succinimide dispersants which are stabilized by the addition of small amounts of a co-dispersant which has a oil-soluble hydrocarbon-substituted mono- or bi-oxazoline or lactone-oxazoline.

US-A-4 505 829 discloses lubricating oil compositions containing polycarboxylic acid glycol esters as friction modifiers in combination with hydrocarbon-soluble alkenyl succinimide dispersants with reduced tendency to sediment formation during storage. The storage stability is improved by the addition of small amounts of polyol or polyol anhydride partial esters of a fatty acid or an ethoxylated fatty acid, an amine or an amide compound.

US-A-4 617 134 relates to storage stable lubricating oil compositions comprising an additive combination of a polycarboxylic acid glycol or glycerol ester as a friction modifier and zinc dihydrocarbon dithiophosphate and an ashless dispersant containing a selected amount of free hydroxyl groups.

US-A-4,684,473 relates to the solubilization of oxygenated (hydroxy)esters of a dimer acid (including linoleic acid dimer esters of polyhydric alcohols) by the incorporation of an oil-soluble C4 to C23 alkanol or an oil-soluble alkyl phosphate into the lubricant composition. It is disclosed that the selection of the chain length of the alcohol is critical.

The present invention provides an oil-soluble mixture which is useful as an oil additive and

(A) ashless lubricating oil additive comprising (1) ashless dispersants selected from known classes of such additives as defined below, and/or

(2) polymeric viscosity index improver dispersants selected from known classes of such additives as defined below, and

(B) Demulsifier additive comprises

characterized in that the demulsifier additive (B) is the reaction product of

(i) alkylene oxide having 2 to 10 carbon atoms and

(ii) an adduct obtained by reacting polyhydric alcohol with bis-epoxide containing at least two oxirane rings linked by a C₁ to C₁₀₀₀ hydrocarbon group, the hydrocarbon group optionally containing (a) one or more alkyl groups, tertiary amino groups and halogens as substituents and/or one or more oxygen atoms, sulfur atoms, carboxy groups, sulfonyl groups, sulfinyl groups, ketone groups, oxirane rings and nitro groups in the carbon chain which are separated from the carbon atom of the oxirane ring by at least one intervening carbon atom, and the demulsifier contains at least 40% by weight of the oxyalkylene units derived from the alkylene oxides having 3 or more carbon atoms.

The additive mixture may also include a metal detergent component (D) as defined below.

According to a preferred embodiment, especially when the additive mixture is used in concentrates (also referred to as packages) and especially when these contain a metal detergent component (D), the mixture comprises 0.1 to 5 parts by weight (based on (B)) of at least one compatibility additive (C) which is an ester or hydroxyamide derivative of a mono- or polycarboxylic acid having a total of 24 to 90 carbon atoms and at least about 1 carboxylic acid group per molecule with a mono-, di- or trihydric alcohol.

The invention extends to a lubricating oil additive concentrate containing 10 to 80% by weight of oil-soluble mixture as defined above dissolved in a hydrocarbon oil. The concentrate can preferably

3 to 45 wt.% of the ashless dispersant (A)(1),

0.01 to 3 wt.% of the demulsifier additive (B),

0.0005 to 2 wt.% of the compatibility additive (C) and

2 to 45 wt.% of the metal detergent additive (D).

The invention also includes a process for forming a concentrate as described above, wherein the ashless dispersant (A)(1) and the metal detergent component (D) are premixed at 70 to 130ºC and the demulsifier additive (B) and the compatibility additive (C) are mixed separately, and the separate mixtures are then mixed together.

It has surprisingly been found that when this mixture of demulsifier (B) and compatibility additive (C) is first formed and then added to a previously formed mixture of ashless dispersant (A)(1) and metal detergent (D), improved storage stability is achieved compared to mixtures of these components prepared using other mixing processes.

Finally, the invention includes a lubricant composition comprising a concentrate as described above or obtainable according to the process described above, which is diluted with 3 to 100 parts by weight (per part by weight of concentrate) of lubricating oil.

Detailed description of the invention Dispersant component A

Dispersant Component A of the oily compositions of the present invention may comprise one or more ashless dispersant materials, one or more polymeric viscosity index improver dispersants, or mixtures thereof. Ashless dispersants and ashless dispersants blended with polymeric viscosity index (VI) improver dispersants are particularly preferred. When the fully formulated lubricating oil is to include both ashless dispersants and polymeric VI improver dispersants, they are generally incorporated into the finished oil as separate additive concentrates since the polymeric VI improver dispersants are generally incompatible with concentrates containing ashless dispersants, metal detergents, and many other conventional lubricant additives. Therefore, it is to be understood that the values given for amounts and proportions of polymeric VI improver dispersants refer to the finished, fully formulated lubricating oil, unless otherwise specified. formulated lubricating oil composition rather than the additive concentrates (which is discussed in more detail below).

A-1

Ashless dispersants useful as component A in accordance with the invention include nitrogen or ester containing dispersants selected from the group consisting of oil soluble amine salts, amides, imides, oxazolines and esters or mixtures thereof of long chain hydrocarbon substituted mono- and dicarboxylic acids or their anhydrides or esters, (ii) long chain aliphatic hydrocarbon having a polyamine directly attached thereto, and (iii) Mannich condensation products formed by condensing about one molar proportion of long chain hydrocarbon substituted phenol with 1 to 2.5 moles of formaldehyde and 0.2 to 2 moles of polyalkylene polyamine, wherein the long chain hydrocarbon group in (i), (ii) or (iii) is a polymer of a C2 to C10, e.g. B. C₂- to C₅-monoolefins and this polymer has an average molecular weight (number average) of at least 900.

A-1(i)

The long chain hydrocarbon substituted mono- or dicarboxylic acid material, i.e., acid, anhydride or ester, may include long chain hydrocarbon, generally a polyolefin, substituted with an average of at least about 0.8, more generally 1.0 to 2.0, and preferably about 1.05 to 1.25, e.g., 1.06 to 1.20 (or 1.10 to 1.20) moles per mole of polyolefin of an α- or β-unsaturated C4 to C10 dicarboxylic acid or its anhydride or ester. Examples of such dicarboxylic acids, their anhydrides or esters are fumaric acid, itaconic acid, maleic acid, maleic anhydride, chloromaleic acid, dimethyl fumarate, chloromaleic anhydride, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, etc.

Preferred olefin polymers for reaction with the unsaturated carboxylic acids to form Component A-1 ashless dispersants 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 such olefins such as copolymers of ethylene and propylene, butylene and isobutylene, etc. Other copolymers include those in which a minor molar amount of the copolymer monomers, e.g., 1 to 10 mole percent, is a non-conjugated C4 to C18 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 fully saturated, for example an ethylene-propylene copolymer prepared by a Ziegler-Natta synthesis using hydrogen as a retarder to control the molecular weight.

The olefin polymers used in the Component A-1 ashless dispersants typically have number average molecular weights of at least about 900, generally in the range of about 1,200 to about 5,000, and more usually between about 1,500 and about 4,000. Particularly useful olefin polymers have number average molecular weights in the range of about 1,500 to about 3,000 with approximately one terminal double bond per polymer chain. A particularly useful starting material for high potency ashless dispersant additives useful in the present invention is polyisobutylene. The number average molecular weight for such polymers can be determined by several known techniques. A convenient method for such a determination is by gel permeation chromatography (GPC), which also provides information on the molecular weight distribution, see W. W. Yau, J. J. Kirkland and D. D. Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979.

Methods for reacting the olefin polymer with the unsaturated C4 to C10 dicarboxylic acid, anhydride or ester thereof are known in the art. For example, the olefin polymer and the dicarboxylic acid material can simply be heated together as disclosed in U.S. Patent Nos. 3,361,673 and 3,401,118 to cause a thermal "ene" reaction to occur. Or the olefin polymer may first be halogenated, for example chlorinated or brominated, to about 1 to 8, preferably 3 to 7, weight percent based on the weight of the polymer by passing chlorine or bromine through the polyolefin for about 0.5 to 10 hours, preferably 1 to 7 hours, at a temperature of 60 to 250°C, e.g. 120 to 160°C. The halogenated polymer may then be reacted with a sufficient amount of unsaturated acid or anhydride for about 0.5 to 10 hours, e.g. 3 to 8 hours, at 100 to 250°C, usually about 180 to 235°C, so that the resulting product contains the desired number of moles of unsaturated acid per mole of halogenated polymer. Methods of this general type are taught in U.S. Patent Nos. 3,087,436, 3,172,892, and 3,272,746, among others.

Alternatively, the olefin polymer and the unsaturated acid material are mixed and heated with chlorine added to the hot material. Processes of this type are disclosed in US Patent Nos. 3,215,707, 3,231,587, 3,912,764, 4,110,349, 4,234,435 and UK-A-1,440,219.

By using halogen, typically 65 to 95 weight percent of the polyolefin, e.g., polyisobutylene, will react with the dicarboxylic acid material. When conducting a thermal reaction without using halogen or a catalyst, typically only about 50 to 75 weight percent of the polyisobutene will react. Chlorination helps to increase reactivity. Conveniently, the recited functionality ratios of dicarboxylic acid producing units to polyolefin, e.g., 1.2 to 2.0, are based on the total amount of polyolefin, that is, the sum of both the reacted and unreacted polyolefin, used to make the product.

The dicarboxylic acid producing materials can also be further reacted with amines, alcohols including polyols and amino alcohols to form other useful dispersant additives. If the acid producing material is to be further reacted, ie neutralized, in the Generally, a larger proportion of at least 50% of the acid units up to the total acid units are converted.

Amine compounds useful as nucleophilic reactants for neutralizing the hydrocarbyl-substituted dicarboxylic acid materials include mono- and (preferably) polyamines, most preferably polyalkylenepolyamines having from 2 to 60 and preferably from 2 to 40 (e.g., 3 to 20) total carbon atoms and from 1 to 12, preferably from 2 or 3 to 12 and most preferably from 2 or 3 to 9 nitrogen atoms in the molecule. These amines can be hydrocarbylamines or hydrocarbylamines which include additional groups, e.g., hydroxy groups, alkoxy groups, amide groups, nitriles, imidazoline groups and the like. Hydroxyamines having from 1 to 6 hydroxy groups, preferably from 1 to 3 hydroxy groups, are particularly useful. Preferred amines are aliphatic, saturated amines including those having the general formulas

wherein Rº, R', R" and R"' are independently selected from the group consisting of hydrogen; straight chain or branched C₁- to C₂₅-alkyl radicals, C₁- to C₁₂-alkoxy-C₂- to C₆-alkylene radicals, C₂- to C₁₂-hydroxyaminoalkylene radicals and C₁- to C₁₂-alkylamino-C₂- to C₆-alkylene radicals, and wherein R"' additionally represents a group having the formula

in which R' is as defined above and in which s and s' may be the same or a different number from 2 to 6 and preferably 2 to 4; and t and t' may be the same or different and are numbers from 0 to 10, preferably 2 to 7 and most preferably about 3 to 7, with the proviso that that the sum of t and t' is not greater than 15. To ensure ease of reaction, it is preferred that Rº, R', R", R"', s, s', t and t' are chosen in a manner sufficient to provide the compounds of formulas Ia and Ib with typically at least one primary or secondary amino group, preferably at least two primary or secondary amino groups. This can be achieved by choosing hydrogen for at least one of the Rº, R', R" or R"' groups or by allowing t in formula V to be at least one when R"' is H or when the Ic group has a secondary amino group. The most preferred amines from the above formulas are represented by formula Ib and contain at least two primary amino groups and at least one and preferably at least three secondary amino groups.

Examples of suitable amine compounds include, but are not limited to: 1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethyleneamines such as diethylenetriamine; triethylenetetramine; tetraethylenepentamine; polypropyleneamines such as 1,2-propylenediamine; di-(1,2-propylene)triamine; di-(1,3-propylene)triamine; N,N-dimethyl-1,3-diaminopropane; N,N-di-(2-aminoethyl)ethylenediamine; N,N-di(2-hydroxyethyl)-1,3-propylenediamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propanediamine; tris-hydroxymethylaminomethane (THAM); diisopropanolamine; diethanolamine; Triethanolamine; mono-, di- and tri(tallow)amines; aminomorpholines 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-aminoalkylpiperazines of the general formula (II):

wherein p₁ and p₂ are the same or different and are each an integer from 1 to 4, and n₁, n₂ and n₃ are the same or different and are each an integer from 1 to 3. Non-limiting examples of such amines include 2-pentadecylimidazoline and N-(2-aminoethyl)piperazine.

Commercial mixtures of amine compounds can be used to advantage. For example, one process for preparing alkylene amines involves reacting an alkylene dihalide (such as dichloroethylene or dichloropropylene) with ammonia, resulting in a complex mixture of alkylene amines in which nitrogen pairs are joined by alkylene groups, resulting in the formation of such compounds as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and the isomeric piperazines. Inexpensive poly(ethyleneamine) compounds containing an average of about 5 to 7 nitrogen atoms per molecule are available under trade names such as "Polyamine H," "Polyamine 400," "Dow Polyamine E-100."

Useful amines also include polyoxyalkylenepolyamines such as those of the formulas,

NH₂-alkylene&lsqbstr;O-alkylene&rsqbstr;NH₂ (III)

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

Riv[alkylene(O-alkylene)NH₂]a (IV)

wherein "c" has a value of about 1 to 40, with the proviso that the sum of all c's is about 3 to about 70 and preferably about 6 to about 35, and Riv is a polyvalent saturated hydrocarbon radical having up to 10 carbon atoms, the number of substituents of the Riv group being represented by "a" which is a number from 3 to 6. The alkylene groups in each of the formulas (III) or (IV) may be straight-chain or branched-chain and contain about 2 to 7, preferably about 2 to 4 carbon atoms.

The polyoxyalkylene polyamines of formulas (III) and (IV) above, preferably polyoxyalkylenediamines and polyoxyalkylenetriamines, may have average molecular weights in the range of 200 to 4,000 and preferably 400 to 2,000. The preferred polyoxyalkylene polyamines include the polyoxyethylene and the polyoxypropylenediamines and the polyoxypropylenetriamines having average molecular weights in the range of 200 to 2,000. The polyoxyalkylene polyamines are commercially available and can be obtained, for example, from Jefferson Chemical Company, Inc., under the trade names "Jeffamines D-230, D-400, D-1000, D-2000, T-403", etc.

The amine is readily reacted with the chosen dicarboxylic acid material, e.g., alkenyl succinic anhydride, by heating an oil solution containing from 5 to 95 weight percent of the dicarboxylic acid material to about 100 to about 250°C, preferably 125 to 175°C, generally for from 1 to 10 hours, e.g., from 2 to 6 hours, until the desired amount of water is removed. The heating is preferably done to favor the formation of imides or mixtures of imides and amides rather than amides and amine salts. The reaction ratios of the dicarboxylic acid material to amine equivalents, as well as the other nucleophilic reactants described herein, can vary considerably depending on the reactants and types of bonds formed. Generally, from 0.1 to 1.0, preferably about 0.2 to 0.6, e.g., B. 0.4 to 0.6 content of dicarboxylic acid units (e.g. content of grafted maleic anhydride) per reactive equivalent of nucleophilic reactant, e.g. amine, is used. For example, preferably about 0.8 moles of a pentamine (having two primary amino groups and five reactive nitrogen equivalents per molecule) is used for conversion to a mixture of amides and imides, the product having been formed by reacting one mole of olefin with sufficient maleic anhydride to add 1.6 moles of succinic anhydride groups per mole of olefin, i.e. the pentamine is used in a sufficient Amount used to provide about 0.4 moles (i.e., 1.6 divided by (0.8 x 5) moles) of succinic anhydride group per nitrogen equivalent of amine.

The nitrogen and ester containing ashless dispersants may preferably be further treated by boration as generally taught in US-A-3,087,936 and US-A-3,254,025. This is conveniently accomplished by treating the selected acyl nitrogen dispersant with a boron compound selected from the class consisting of boron oxide, boron halides, boric acids and esters of boric acids in an amount to provide from about 0.1 atomic parts boron for each mole of nitrogen dispersant up to about 20 atomic parts boron for each atomic part nitrogen of the acylated nitrogen dispersants. Useful dispersants of the combination of the invention contain from about 0.05 to 2.0 wt.%, e.g. B. 0.05 to 0.7 weight percent boron based on the total weight of the borated acyl nitrogen dispersant. It is believed that the boron, which appears to be present in the product as dehydrated boric acid polymers (primarily (HBO₂)₃), attaches to the dispersant imides and diimides as amine salts, e.g. the metaborate salt of this diimide.

The treatment is conveniently carried out by adding about 0.05 to 4, e.g. 1 to 3, weight percent (based on the weight of the acyl nitrogen compound) of the boron compound, preferably boric acid, which is usually added as a slurry to the acyl nitrogen compound, and heating with stirring to about 135 to 190°C, e.g. 140 to 170°C, for 1 to 5 hours, followed by nitrogen stripping in these temperature ranges. The boron treatment can also be carried out by adding boric acid to the hot reaction mixture of the dicarboxylic acid material and amine while removing water.

The tris(hydroxymethyl)aminomethane (THAM) can be reacted with the said acid material to form amides, imides or ester type additives as taught by UK-A-984 409 or to form oxazoline compounds and borated oxazoline compounds, as described, for example, in US-A-4,102,798, US-A-4,116,876 and US-A-4,113,639.

The ashless dispersants can also be esters derived from the reaction of the above long chain hydrocarbon substituted dicarboxylic acid material and hydroxy compounds such as monohydric and polyhydric alcohols or aromatic compounds such as phenols or 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 glycerin, glycerin monooleate, glycerin monostearate, glycerin monomethyl ether, pentaerythritol, dipentaerythritol and mixtures thereof.

The ester dispersant may also be derived from unsaturated alcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexen-3-ol and oleyl alcohol. Still other classes of alcohols capable of yielding the esters of the present invention include the ether alcohols and amino alcohols including, for example, the oxyalkylene, oxyarylene, aminoalkylene and aminoarylene substituted alcohols having one or more oxyalkylene, oxyarylene, aminoalkylene or aminoarylene radicals. Examples include Cellosolve (trade name), Carbitol, N,N,N',N'-tetrahydroxytrimethylenediamine and ether alcohols having up to about 150 oxyalkylene radicals in which the alkylene radical contains from 1 to about 8 carbon atoms.

The ester dispersants may be diesters of succinic acids or acid esters, i.e. partially esterified succinic acids, as well as partially esterified polyhydric alcohols or phenols, i.e. esters having free alcohol or phenol hydroxyl residues. Mixtures of the esters illustrated above are equally within the scope of this invention.

The ester dispersants can be prepared by one of many known processes, for example, as described in US-A-3 381 022 and US-A-3 836 471. Similar to the nitrogen-containing dispersants described above, the ester dispersants can also be borated.

Hydroxyamines which can be reacted with the above long chain hydrocarbon substituted dicarboxylic acid materials to form dispersants include 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, p-(β-hydroxyethyl)aniline, 2-amino-1-propanol, 3-amino-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, N-(β-hydroxypropyl)-N'-(β-aminoethyl)piperazine, tris(hydroxymethyl)aminomethane (also known as trismethylolaminomethane), 2-amino-1-butanol, ethanolamine, β-(β-hydroxyethoxy)ethylamine, and the like. Mixtures of these or similar amines may also be used. The above description of nucleophilic reactants suitable for reaction with the hydrocarbyl-substituted dicarboxylic acid or its anhydride includes amines, alcohols, and compounds having mixed amine and hydroxyl-containing reactive functional groups, i.e., amino alcohols.

A preferred group of ashless dispersants are those derived from polyisobutylene substituted with succinic anhydride groups and reacted with the polyethylene amines, e.g. tetraethylenepentamine, pentaethylenehexamine, polyoxyethylene and polyoxypropylene amines, e.g. polyoxypropylenediamine, trismethylolaminomethane, or the alcohols described above such as pentaerythritol, and combinations thereof. A particularly preferred combination of dispersants includes a combination of (i) polyisobutene substituted with succinic anhydride groups and reacted with (ii) a hydroxy compound, e.g. pentaerythritol, (iii) a polyoxyalkylene polyamine, e.g. polyoxypropylenediamine, and (iv) a polyalkylene polyamine, e.g. B. polyethylenediamine and tetraethylenepentamine, using from about 0.3 to about 2 moles of each of (ii) and (iv) and from about 0.3 to about 2 moles of (ii) per mole of (i) as described in US-A-3 804 763. Another preferred combination of ashless dispersants includes the combination of (i) polyisobutenyl succinic anhydride with (ii) a polyalkylenepolyamine, e.g. tetraethylenepentamine, and (iii) a polyhydric alcohol or polyhydroxy substituted aliphatic primary amine, e.g. pentaerythritol or trismethylolaminomethane as described in US-A-3,632,511.

A-1(ii)

Also useful as the ashless nitrogen-containing dispersant of the present invention are dispersants in which a nitrogen-containing polyamine is directly bonded to the long chain aliphatic hydrocarbon, as shown in U.S. Patent Nos. 3,275,554 and 3,565,804, where the halogen group on the halogenated hydrocarbon is displaced by various alkylene polyamines.

A-1(iii)

Another class of nitrogen-containing dispersants that can be used are those containing Mannich bases or Mannich condensation products, which are known in the art. Such Mannich condensation products are generally prepared by condensing about 1 mole of high molecular weight hydrocarbon-substituted mono- or polyhydroxybenzene (e.g., having a number average molecular weight of 1,000 or more) with about 1 to 2.5 moles of formaldehyde or paraformaldehyde and about 0.5 to 2 moles of polyalkylenepolyamine, as disclosed, for example, in U.S. Patent Nos. 3,442,808, 3,649,229, and 3,798,165. Such Mannich condensation products may include a long chain high molecular weight hydrocarbon on the phenol group or may have been reacted with a compound containing such a hydrocarbon, e.g., polyalkenyl succinic anhydride as shown in the aforementioned US-A-3,442,808.

A-2

Examples of suitable polymeric viscosity index improver dispersants include:

(i) polymers composed of unsaturated C4 to C24 esters of vinyl alcohol or unsaturated C3 to C10 mono- or dicarboxylic acid with unsaturated nitrogen-containing monomers having 4 to 20 carbon atoms;

(ii) polymers of C₂- to C₂₀-olefin with unsaturated C₃- to C₁₀-mono or dicarboxylic acids neutralized with amine, hydroxyamine or alcohols; and

(iii) Polymers of ethylene with a C3 to C20 olefin which have been further reacted either by grafting unsaturated nitrogen-containing monomers or by grafting an unsaturated acid onto the polymer backbone and subsequently reacting the carboxylic acid groups with amine, hydroxyamine or alcohol.

In these polymers, the amine, hydroxyamine or the "mono- or polyhydric" alcohol may be as described above with respect to the ashless dispersant compounds.

It is preferred that the polymeric viscosity index improver dispersant has a range of number average molecular weight as determined by vapor phase osmometry, membrane osmometry or gel permeation chromatography of 1,000 to 2,000,000, preferably 5,000 to 250,000 and most preferably 10,000 to 200,000. It is also preferred that the polymers of group (i) comprise a major amount by weight of unsaturated ester and a minor amount, e.g. 0.1 to 40, preferably 1 to 20 wt.% of a nitrogen-containing unsaturated monomer, the wt.% being based on the total polymer. Preferably, polymer group (ii) comprises 0.1 to 10 moles of olefin, preferably 0.2 to 5 moles of C2 to C20 aliphatic or aromatic olefin moieties per mole of unsaturated carboxylic acid moiety, and preferably 50% to 100% of the acid groups are neutralized. Preferably, the polymer of group (iii) comprises an ethylene copolymer of 25 to 80 wt.% ethylene with 75 to 20 wt.% C3 to C20 mono- and/or diolefin, wherein 100 parts by weight of ethylene copolymer is grafted with either 0.1 to 40, preferably 1 to 20 parts by weight of unsaturated nitrogen-containing monomer or is grafted with 0.01 to 5 parts by weight of unsaturated C3 to C10 mono- or dicarboxylic acid, the acid being 50% or more neutralized.

The unsaturated carboxylic acids used in (i), (ii) and (iii) above preferably contain 3 to 10, more usually 3 to 4, carbon atoms and may be monocarboxylic acids such as methacrylic and acrylic acid or dicarboxylic acids such as maleic acid, maleic anhydride or fumaric acid.

Examples of unsaturated esters that can be used include those of aliphatic saturated monoalcohols having at least one carbon atom and preferably 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 monocarboxylic acids, preferably saturated acids, such as vinyl acetate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate and the like, and mixtures thereof.

Such ester polymers can be grafted or copolymerized with polymerizable unsaturated nitrogen-containing monomers to impart dispersibility to the VI improvers. Examples of suitable unsaturated nitrogen-containing monomers for imparting dispersibility include those having from 4 to 20 carbon atoms such as amino-substituted olefins such as p-(β-diethylaminoethyl)styrene, basic nitrogen-containing heterocycles having a polymerizable ethylenically unsaturated substituent, e.g. B. the vinylpyridines and the vinylalkylpyridines such as 2-vinyl-5-ethylpyridine, 2-methyl-5- vinylpyridine, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 3-methyl-5-vinylpyridine, 4-methyl-2-vinylpyridine, 4-ethyl-2-vinylpyridine and 2-butyl-5-vinylpyridine and the like.

N-vinyllactams are also suitable, e.g. N-vinylpyrrolidones or n-vinylpiperidone. The vinyl radical is preferably unsubstituted (CH₂=CH-), but can be substituted with an aliphatic hydrocarbon group with 1 to 2 carbon atoms such as ethyl or methyl.

The vinylpyrrolidones are preferred and examples thereof are N-vinylpyrrolidone, N-(1-methyl-vinyl)pyrrolidone, N-vinyl-5- methylpyrrolidone, N-vinyl-3,3-dimethylpyrrolidone, N-vinyl-5- ethylpyrrolidone, N-vinyl-4-butylpyrrolidone, N-ethyl-3-vinylpyrrolidone, N-butyl-5-vinylpyrrolidone, 3-vinylpyrrolidone, 4-vinylpyrrolidone, 5-vinylpyrrolidone and 5-cyclohexyl-N-vinylpyrrolidone and the like.

Examples of olefins that can be used to prepare the above copolymers of (ii) and (iii) include monoolefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-decene, 1-dodecene, styrene, etc.

Representative non-limiting examples of diolefins that can be used in (iii) include 1,4-hexadiene, 1,5-heptadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, vinylcyclohexane, dicyclopentenyl and 4,4'-dicyclohexenyl such as tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo[2,2,1]hepta-2,5-diene, alkenyl, alkylidiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene.

Typical polymeric viscosity index improver dispersants include copolymers of alkyl methacrylates with N-vinylpyrrolidone or dimethylaminoalkyl methacrylate, alkyl fumarate-vinyl acetate, N-vinylpyrrolidine copolymers, interpolymers of ethylene-propylene post-grafted with an active monomer such as maleic anhydride, which may have been further reacted with an alcohol or an alkylene polyamine, see, for example, U.S. Pat. B. US-A-4 089 794, US-A-4 160 739, US-A-4 137 185, or copolymers of ethylene and propylene which may have been reacted or grafted with nitrogen compounds as shown in US-A-4 068 056, US-A-4 068 058, US-A-4 146 489, US-A-4 149 984, styrene/maleic anhydride polymers which have been subsequently reacted with alcohols and amines, ethoxylated derivatives of acrylate polymers, see for example US-A-3 702 300. Also usable are styrene-isobutylene and styrene-maleic anhydride copolymers and terpolymers and the like which have been reacted with nitrogen-containing compounds (e.g. polyalkylenepolyamines, piperidines, morpholines, hydrazines and the like) and Mannich base condensation product derivatives as disclosed in US-A-3,493,520, US-A-3,558,743, US-A-3,634,493, US-A-3,684,713, US-A-3,933,761, US-A-3,956,149, US-A-3,959,159, US-A-4,029,702 and US-A-4,424,317, HU-B-25,896, SU-A-235,232 and SU-A-1,121,268 and UK-A-2,124,633.

Demulsifier component B

The demulsifier additives for lubricating oil according to the invention are the water-insoluble, at least partially oil-soluble product from the reaction of (i) alkylene oxide having 2 to 10 carbon atoms and (ii) an adduct obtained by reacting bis-epoxide, preferably a diglycidyl ether of bisphenol A, and a polyhydric alcohol, preferably a polyoxyalkylene glycol.

In the preparation of the demulsifiers according to the invention, a first adduct is prepared by reacting a bis-epoxide with a polyhydric alcohol.

The bis-epoxides are compounds that contain at least two oxirane rings, i.e.

These oxirane rings are linked or connected by hydrocarbon groups or hydrocarbon groups containing at least one heteroatom or a group as defined below. The hydrocarbon groups contain 1 to 100 carbon atoms. They include the alkylene, cycloalkylene, alkenylene, arylene, aralkenylene and alkarylene radicals. Typical alkylene radicals are those having 1 to 100 carbon atoms, typically 1 to 50 carbon atoms. The alkylene radicals can be straight chain or branched and can contain 1 to 100 carbon atoms, preferably 1 to 50 carbon atoms. Typical cycloalkylene radicals are those having 4 to 16 ring carbon atoms. The cycloalkylene radicals can contain alkyl substituents, e.g. C₁ to C₈ alkyl, on one or more ring carbon atoms. Typical arylene radicals are those having 6 to 12 ring carbon atoms, e.g. phenylene, naphthylene and biphenylene. Typical alkarylene and aralkylene radicals are those having 7 to 100 carbon atoms, preferably 7 to 50 carbon atoms. The hydrocarbon groups linked to the oxirane ring may contain substituent groups. The substituent groups are those which are essentially inert or unreactive with the oxirane ring under ambient conditions. As used in the description, the The term "substantially inert and unreactive at ambient conditions" means that the atom or group is substantially inert to chemical reactions with the oxirane ring at ambient temperatures and pressures so as not to substantially adversely interfere with the manufacture and/or performance of the compositions, additives, compounds of the invention in the context of their intended use. For example, small amounts of these atoms or groups may undergo minimal reaction with the oxirane ring without preventing the manufacture and use of the invention as described herein. In other words, such a reaction, while technically possible, would not be sufficient to prevent the ordinary skill in the art from making and using the invention for its intended purpose. Suitable substituent groups are alkyl groups, hydroxyl groups, tertiary amino groups, and halogens. When more than one substituent is present, they may be the same or different.

It is to be understood that although many substituent groups are substantially inert or unreactive with the oxirane ring at ambient conditions, they will react with the oxirane ring under effective conditions that permit reaction of the oxirane ring with the reactive hydroxy groups of the polyhydric alcohols. Whether these groups are suitable substituent groups to be present on the bis-epoxide depends in part on their reactivity with the oxirane ring. If they are substantially more reactive with the oxirane ring than the oxirane ring with the reactive hydroxy group, they will generally tend to significantly and deleteriously interfere with the preparation of the intended demulsifiers of the invention and are therefore unsuitable. However, if their reactivity with the oxirane ring is less than or generally similar to the reactivity of the oxirane ring with the reactive hydroxy groups, they will not significantly interfere in a detrimental manner with the preparation of the demulsifiers of the invention and may be present on the bis-epoxide, particularly if the epoxide groups are present in relative excess to the substituent groups. An example An example of such a reactive but suitable group is the hydroxyl group. An example of an unsuitable substituent group is a primary amino group.

The hydrocarbon groups containing at least one heteroatom or group are the hydrocarbon groups described above containing at least one heteroatom or heterogroup in the chain. The heteroatoms or groups are those that are substantially unreactive with the oxirane rings under ambient conditions. When more than one heteroatom or group is present, they may be the same or different. The heteroatoms or groups are separated from the carbon atom of the oxirane ring by at least one intervening carbon atom. These hydrocarbon groups containing the heteroatom or heterogroup may contain at least one substituent group on at least one carbon atom. These substituent groups are the same as those described above as suitable for the hydrocarbon groups.

Suitable heteroatoms or groups that can be in the carbon chain of the hydrocarbon group are:

Oxygen atoms (i.e. -O- or ether bonds in the carbon chain);

Sulfur atoms (i.e. -S- or thioether bonds in the carbon chain);

Carboxy groups (i.e. - - O - ;)

Sulfonyl group

Keto group

(i.e. - -);

Sulfinyl group

(i.e. - -);

an oxirane ring

and nitro group.

As mentioned so far, the bisepoxides of the invention contain at least two oxirane rings or epoxide groups. It is critical that the bisepoxide contains at least two oxirane rings in the same molecule.

The bis-epoxides useful in the present invention are well known in the art and are generally commercially available or can be readily prepared by conventional and well-known methods.

The bis-epoxides include those with the general formula

an Indian:

R is a divalent hydrocarbon radical, a substituted divalent hydrocarbon radical, a divalent hydrocarbon radical containing at least one heteroatom or heterogroup, and a substituted divalent hydrocarbon radical containing at least one heteroatom or heterogroup;

R¹ and R⁶ are independently selected from hydrogen, monovalent hydrocarbon radicals, substituted monovalent hydrocarbon radicals, monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup, or substituted monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup, and oxirane-containing radicals,

R² and R³ are independently selected from hydrogen, monovalent hydrocarbon radicals, substituted monovalent hydrocarbon radicals, monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup, or substituted monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup, monovalent oxirane-containing radicals, divalent hydrocarbon radicals and substituted divalent hydrocarbon radicals, with the proviso that when R² or R³ is a divalent hydrocarbon radical or substituted divalent hydrocarbon radical, then both R² and R³ are divalent hydrocarbon radicals or substituted divalent hydrocarbon radicals which together with the two carbon atoms of the oxirane ring form a cyclic structure, and

R⁴ and R⁵ are independently selected from hydrogen, monovalent hydrocarbon radicals, substituted monovalent hydrocarbon radicals, monovalent hydrocarbon radicals containing at least one heteroatom or heteroatom group, substituted monovalent hydrocarbon radicals containing at least one heteroatom or heteroatom group, divalent hydrocarbon radicals and substituted divalent hydrocarbon radicals, with the proviso that when R⁴ or R⁵ is a divalent hydrocarbon radical or substituted divalent hydrocarbon radical, then both R⁴ and R⁵ are divalent hydrocarbon radicals or substituted divalent hydrocarbon radicals which together with the two carbon atoms of the oxirane ring form a cyclic structure.

The monovalent hydrocarbon radicals represented by R¹ to R⁶ generally contain 1 to 100 carbon atoms. These hydrocarbon radicals include alkyl, alkenyl, cycloalkyl, aryl, aralkyl and alkaryl radicals. The alkyl radicals can contain 1 to 100, preferably 1 to 50 carbon atoms and can be straight-chain or branched. The alkenyl radicals can contain 2 to 100 carbon atoms and preferably 2 to 50 carbon atoms and can be straight-chain or branched. Preferred cycloalkyl radicals are those with 4 to 12 ring carbon atoms, e.g. cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl. These cycloalkyl radicals can carry substituent groups, preferably alkyl groups, on the ring carbon atoms, e.g. B. Methylcyclohexyl, 1-3-dimethylcyclopentyl. The preferred alkenyl groups are those with 2 to 30 carbon atoms, e.g. ethenyl, 1-propenyl, 2-propenyl. The preferred aryl radicals are those containing 6 to 12 ring carbon atoms, e.g. phenyl, naphthyl and bisphenyl. The preferred aralkyl and alkaryl radicals are those with 7 to 30 carbon atoms, e.g. p-tolyl, 2,6-xylyl, 2,4,6-trimethylphenyl, 2-isopropylphenyl, benzyl, 2-phenylethyl, 4-phenylbutyl.

The substituted monovalent hydrocarbon radicals represented by R¹ to R⁶ are the monovalent hydrocarbon radicals described above which contain at least one substituent group. The substituent groups are those which are substantially unreactive with the oxirane groups under ambient conditions. When more than one substituent group is present, they may be the same or different.

The monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup are the previously described hydrocarbon radicals containing at least one heteroatom or heterogroup in the carbon chain. The heteroatom or heterogroup is separated from the carbon of the oxirane ring by at least one intervening carbon atom. If more than one heteroatom or heterogroup is present, they may be the same or different. The heteroatoms or groups are those which, under ambient conditions, are essentially unreactive with the oxirane ring. These heteroatoms or groups are those previously described.

The substituted monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup are the substituted monovalent hydrocarbon radicals containing at least one heteroatom or heterogroup as described above and carrying at least one substituent group on at least one carbon atom. The substituent groups are those as previously described.

The oxirane residues represented by R¹ to R⁶ can be represented by the formula

be reproduced in the

R⁷ has the same meaning as R¹, R⁸ to R⁹ have the same meaning as R² to R³, and R¹⁰ has the same meaning as R in formula V. The divalent hydrocarbon radicals represented by R² to R⁵ and R⁸ to R⁹ are aliphatic acyclic radicals and contain 1 to 5 carbon atoms. Preferred divalent hydrocarbon radicals are the alkylene radicals. Preferred alkylene radicals are those which together with the two carbon atoms of the oxirane ring form a cyclic structure containing 4 to 8 ring carbon atoms. For example, if R³ and R⁴ are both ethylene radicals, the resulting cyclic structure formed with the two carbon atoms of the oxirane ring is a cyclohexene oxide, i.e.

The divalent substituted hydrocarbon radicals represented by R² to R⁵ and R⁸ to R⁹ are the divalent hydrocarbon radicals described above which contain at least one substituent group on at least one carbon atom. Thus, when R³ and R⁴ are both hydroxy-substituted ethylene radicals, the resulting cyclic structure formed with the two carbon atoms of the oxirane ring can be represented by the formula:

be reproduced.

The divalent hydrocarbon radicals represented by R and R¹⁰ generally contain 1 to 100 carbon atoms, preferably 1 to 50 carbon atoms. They may be aliphatic, aromatic or aliphatic-aromatic. When aliphatic, they may be saturated or unsaturated, acyclic or alicyclic. They include alkylene, cycloalkylene, alkenylene, arylene, aralkylene and alkarylene radicals. The alkylene radicals may be straight-chain or branched. Preferred alkylene radicals are those having 1 to 50 carbon atoms. Preferred alkenylene radicals are those having 2 to 50 carbon atoms. Preferred cycloalkylene radicals are those having 4 to 12 ring carbon atoms. The cycloalkylene radicals can carry substituents, preferably alkyl, on the ring carbon atoms.

It is to be understood that the term "arylene" as used in the specification and the appended claims is not intended to limit the divalent aromatic group represented by R and R¹⁰ to benzene. Therefore, it is to be understood that the divalent aromatic group may be a single aromatic nucleus such as a benzene nucleus, a pyridine nucleus, a thiophene nucleus, a 1,2,3,4-tetrahydronaphthalene nucleus, etc., or a polynuclear aromatic group. Such polynuclear groups may be of the condensed type, that is, in which at least one aromatic nucleus is connected at two points to another nucleus, as found in naphthalene, anthracene, the azanaphthalenes, etc. Alternatively, such polynuclear aromatic groups may be of the linked type in which at least two nuclei (either mononuclear or polynuclear) are bonded to one another by bridging bonds. Such bridging bonds may be selected from the group consisting of carbon-carbon single bonds, ether bonds, keto bonds, sulfide bonds, polysulfide bonds having 2 to 6 sulfur atoms, sulfinyl bonds, sulfonyl bonds, methylene bonds, alkylene bonds, di(lower alkyl)methylene bonds, lower alkylene ether bonds, alkylene keto bonds, lower alkylene sulfur bonds, lower alkylene polysulfide bonds having 2 to 6 carbon atoms, amino bonds, polyamino bonds, and mixtures of such divalent bridging bonds.

If the divalent aromatic group Ar is a linked polynuclear aromatic group, it can be represented by the general formula

Ar(Lng-Ar)r

wherein r is an integer from 1 to 10, preferably 0 to 8, especially 1, 2 or 3, Ar is a divalent aromatic group as described above and each "Lng" is a bridging bond individually selected from the group consisting of carbon-carbon single bonds, Ether bonds (e.g. -O-), keto bonds

(e.g. - -)

Sulfide bonds (e.g. (-S-), polysulfide bonds with 2 to 6 sulfur atoms (e.g. -S₂-), sulfinyl bonds (e.g. -S(O)-), sulfonyl bonds (e.g. -S(O)₂-), lower alkylene bonds (e.g. -CH₂-, -CH₂-CH₂-,

Etc.)

di(lower alkyl)methylene bonds (e.g. -CR*₂-), lower alkylene ether bonds (e.g. -CH₂-O-, -CH₂-O-CH₂-, -CH₂-CH₂-O-, -CH₂CH₂OCH₂CH₂-,

lower alkylene sulfide bonds (e.g. in which one or more -O- atoms in the lower alkylene ether bonds are replaced by an -S- atom), lower alkylene polysulfide bonds (e.g. in which one or more -O- atoms in the lower alkylene ether bonds are replaced by an -S₂- to -S₆- group), where R* is a lower alkyl group.

Examples of such linked polynuclear aromatic groups are those with the formula

, in which R¹² and R¹³ are independently selected from hydrogen and alkyl radicals, preferably alkyl radicals having 1 to 20 carbon atoms, R¹¹ is selected from alkylene, alkylidene, cycloalkylene and cycloalkylidene radicals, and u and u¹ are independently selected from integers having a value of 1 to 4.

The divalent substituted hydrocarbon radicals represented by R and R¹⁰ are those divalent hydrocarbon radicals described above which contain at least one substituent group of the type described above. For example, when the divalent hydrocarbon radical is a C₅-alkylene, the corresponding divalent substituted hydrocarbon radical, e.g. hydroxy-substituted radical,

If more than one substituent group is present, they may be the same or different.

The divalent hydrocarbon radicals containing at least one heteroatom or heterogroup are those previously described divalent hydrocarbon radicals containing at least one heteroatom or heterogroup. These heteroatoms or groups are those previously described. Some illustrative, non-limiting examples of divalent hydrocarbon radicals containing at least one heteroatom or heterogroup include:

The divalent substituted hydrocarbon radicals containing at least one heteroatom or heterogroup are those previously described divalent hydrocarbon radicals containing at least one heteroatom or heterogroup and containing at least one substituent group of the type previously described. Some illustrative, non-limiting examples of divalent substituted hydrocarbon radicals containing at least one heteroatom or heterogroup include:

Also included in the scope of the bis-epoxides according to the invention are those having the formula (VII)

in the

R and R¹ to R³ are as previously defined, R¹⁴ and R¹⁵ independently have the same meaning as R¹, X is an aromatic group, R¹⁶ and R¹⁷ are independently selected from divalent aliphatic acyclic hydrocarbon radicals and divalent substituted aliphatic acyclic hydrocarbon radicals which together with the two carbon atoms of the oxirane ring and the two adjacent ring carbon atoms of the aromatic group X form a cyclic structure, m and m¹ are independently zero or 1, and p is zero or 1.

The aromatic groups represented by X are preferably those having 6 to 12 carbon atoms, e.g. benzene, naphthalene and biphenyl. The aromatic groups may bear one or more substituents on one or more ring carbon atoms. These substituents are those which are substantially unreactive with the oxirane ring under ambient conditions, e.g. temperature and pressure. They include, for example, alkyl, hydroxyl, nitro and the like.

Also in the range of bis-epoxides according to the invention are those with the formula (VIII):

, in the

R, R¹ to R³, R¹⁴ to R¹⁵ and p are as previously defined and R¹⁸ is independently selected from divalent hydrocarbon radicals or substituted divalent hydrocarbon radicals which together with the two carbon atoms of the oxirane ring form a cyclic, preferably cycloaliphatic structure.

The divalent hydrocarbon or substituted divalent hydrocarbon radicals represented by R¹⁹8 preferably contain 2 to 14 carbon atoms so as to form, together with the two carbon atoms of the oxirane ring, a 4- to 16-membered ring structure, preferably an aliphatic ring. The preferred divalent hydrocarbon radicals are the divalent aliphatic hydrocarbon radicals, preferably the alkylene radicals.

The divalent aliphatic hydrocarbon radicals represented by R18 may contain one or more substituent groups on one or more ring carbon atoms. The substituents are selected from those which are substantially unreactive with the oxirane ring under ambient conditions, e.g., alkyl, hydroxyl, and the like.

Preferred bis-epoxides according to the invention are those in which the oxirane rings (of which preferably at least one is a terminal or end oxirane ring) are unhindered. By unhindered is meant that the oxirane ring contains a secondary carbon atom, ie two hydrogen atoms are bonded to it, and preferably one secondary carbon atom and contains a tertiary carbon atom, ie, a hydrogen is bonded thereto. For example, an unhindered bis-epoxide of formula V is one in which R¹, R², R⁵ and R⁶ are hydrogen, and preferably one in which R¹ to R³ and R⁴ to R⁶ are all hydrogen.

Some illustrative non-limiting examples of the bis-epoxides of the invention include:

The bis-epoxides useful in the present invention also include the epoxy resins. These epoxy resins are well known in the art and are generally commercially available. They are described, for example, in F.W.Jr. Billmeyer, Textbook of Polymer Science, 2nd Edition, Wiley-Interscience, New York, 1971, pages 479 to 480, H. Lee and K. Neville, "Epoxy Resins"' pages 209 - 271, in H.F. Mark, N.G. Gaylord and N.M. Bikales, editors, Encyclopedia of Polymer Science and Technology, Volume 6, Interscience Div. John Wiley and Sons, New York, 1967, and in US-A-3,477,990 and US-A-3,408,422.

The epoxy resins include those compounds that have one or two terminal epoxy groups. These bis-epoxides are saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and are optionally substituted with non-interfering substituents such as halogen atoms, hydroxyl groups, ether radicals and the like.

Preferred bis-epoxides are the glycidyl polyethers of polyhydric phenols and polyhydric alcohols, in particular the glycidyl polyethers of 2,2-bis(4-hydroxyphenyl)propane with an average molecular weight between 300 and 3,000 and an epoxy equivalent weight (WPE) between 140 and 2,000. Particularly preferred are the diglycidyl polyethers of 2,2-bis(4-hydroxyphenyl)propane with a WPE between 140 and 500 and an average molecular weight of 300 to 900.

Other suitable epoxy compounds include those compounds derived from polyhydric phenols having at least one vicinal epoxy group in which the carbon-to-carbon bonds in the six-membered ring are saturated. Such epoxy resins can be obtained by at least two well-known techniques, i.e., by hydrogenation of the glycidyl polyethers of polyhydric phenols or (2) by reaction of the hydrogenated polyhydric phenols with epichlorohydrin in the presence of a suitable catalyst such as Lewis acids, i.e., boron trihalides and complexes thereof, followed by dehydrochlorination in an alkaline medium. The process of preparation does not form part of the present invention. Invention and the resulting saturated epoxy resins derived from each of the processes are useful in the invention.

Briefly, the first process involves hydrogenating glycidyl polyethers of polyhydric phenols with hydrogen in the presence of a catalyst composed of rhodium and/or ruthenium supported on an inert support, at a temperature below about 50°C. The process is fully disclosed and described in U.S. Patent No. 3,336,241, issued August 15, 1967.

The hydrogenated epoxy compounds prepared by the process disclosed in US-A-3,336,241 are suitable for use in the compositions of the invention.

The second process involves the condensation of a hydrogenated polyphenol with an epihalohydrin such as epichlorohydrin in the presence of a suitable catalyst such as BF3, followed by dehydrohalogenation in the presence of alkali. When the phenol is hydrogenated bisphenol A, the resulting saturated epoxy compound is sometimes referred to as "di-epoxidized hydrogenated bisphenol A" or, more appropriately, the diglycidyl ether of 2,2-bis(4-cyclohexanol)propane.

In any event, the term "saturated epoxy resin" as used herein shall mean the glycidyl ethers of polyhydric phenols in which the aromatic ring structure of the phenols is or has been saturated.

Preferred saturated epoxy resins are the hydrogenated resins prepared by the process described in US-A-3,336,241. Particularly preferred are the hydrogenated glycidyl ethers of 2,2-bis(4-hydroxyphenyl)propane, sometimes referred to as diglycidyl ethers of 2,2-bis(4-cyclohexanol)propane.

One class of useful epoxy resins are those prepared by condensing epichlorohydrin with bisphenol A. They include resins represented by the general structural formula (IX)

be reproduced in the

R¹ to R⁶ are as previously defined and preferably all hydrogen,

R²⁰ is independently selected from alkyl radicals, preferably alkyl radicals having 1 to 10 carbon atoms, hydroxyl or halogen radicals,

R²¹ is independently selected from alkyl radicals, preferably alkyl radicals having 1 to 10 carbon atoms, hydroxyl or halogen radicals,

v is independently selected from integers having a value from 0 to 4 inclusive, and

w is independently selected from integers having a value from 0 to 4 inclusive, and

f has a value of at least 1 and varies depending on the molecular weight of the resin, the upper limit of f preferably not exceeding about 10 and in particular not exceeding about 5.

Preferred compounds of formula IX are those in which R¹ to R⁶ are all hydrogen, and v and w are all zero.

An example of commercially available and usable epoxy resins are the EPON resins from Shell Oil Company.

As previously mentioned, those bis-epoxides, including the epoxy resins, in which the two carbon atoms of the oxirane ring are bonded to three hydrogen atoms, e.g. in which R¹ to R⁶ in formula V are all hydrogen, are preferred. Preferred bis-epoxides of this type are those in which the hydrocarbon groups bridging the epoxy groups, e.g. R in formula V, polar groups or atoms. These polar groups or atoms include the polar heteroatoms or groups described above. Particularly preferred bis-epoxides are the epoxy resins, especially those derived from polyhydric phenols.

In the preferred compositions of the invention, the epoxide equivalent of the epoxide of the polyphenol is preferably limited to a minimum of 145 and a maximum of less than 250. This epoxide equivalent is defined as the number of grams of material containing one (1) epoxide group. Thus, a suitable starting material is a substance known as Epon 828, which is a commercially available epoxidized dihydroxy-di-phenyldimethylmethane having an average epoxide equivalent of 175 to 210. Other similar commercially available products are available and can be used as the bis-epoxide. Examples of these commercially available products are the bis-epoxides of polynuclear phenol. These products usually consist largely of the diglycidyl ether of diphenyldimethylmethane. The diglycidyl ether of diphenylmonomethylmethane and the diphenylmethane diglycidyl ether can be used as reactants.

The mono- or polyhydric alcohol reactants can be at least one member of the group consisting of alcohols with the formula:

R²²(OH)x (X)

in which R²² is a hydrocarbon group or represents a hydrocarbon chain which optionally contains one or more heteroatoms in the chain (e.g. O, S or N) and x is a number from 1 to 8, e.g. 2 to 5 (preferred). Preferred polyhydric alcohols are the polyoxyalkylene glycols with the formula

HO-(MO)y(TO)qH (XI)

, in which M and T are the same or different and are alkylene groups having at least 2 carbon atoms, in which the sum of y and q is in the range from 15 to 250, so that the total average molecular weight of the polyoxyalkylene glycol is at least 1,000, preferably 1,000 to 10,000, especially 2,000 to 8,000. Preferably M and T are either 3 or 4 carbon atoms and therefore the polyoxyalkylene glycol comprises polypropylene glycol, polybutylene glycol or block copolymer blends thereof.

The selected polyhydric alcohol and bis-epoxide reactants are contacted for reaction in a weight:weight ratio of polyhydric alcohol to bis-epoxide of 10:1 to 20:1, preferably 14:1 to 18:1.

The reaction conditions for forming the first adduct vary depending on such factors as the polyhydric alcohol and bisepoxide used, the presence of solvent for the reaction and other factors. Generally, temperatures within the range of 110 to 200°C and preferably 120 to 170°C are used.

The reaction to form the first adduct can be carried out in the presence of a solvent for the reaction, such as a hydrocarbon solvent, e.g., toluene, xylene, and the like. The amount of solvent chosen is not critical, although the solvent, e.g., toluene, is generally used in the range of 25 to 75 parts by weight of solvent per 100 parts of the first adduct by weight.

The pressure used in the reaction to form the first adduct is not critical and can be subatmospheric, atmospheric or superatmospheric.

The reaction of the selected polyhydric alcohol and bisepoxide can be carried out in the presence of a small amount of catalyst for the reaction, such as a Lewis base, e.g. caustic soda or caustic potash, which can be used in the range of about 0.2 to 0.5% by weight of all components introduced into the reaction mixture.

The adduct formed by the reaction of the polyhydric alcohol and the bis-epoxide can be illustrated by the following equation, which illustrates the reaction of polypropylene glycol and the diglycidyl ether of bis-phenol A.

in which r₁ has a value sufficient to match the number average molecular weight of the polypropylene glycol. For example, r₂ generally ranges from about 5 to about 120 for polypropylene glycols having number average molecular weights of from about 4,000 to about 7,000.

It is not essential that the reaction to form the first adduct be carried to completion, and it is to be understood that the reaction mass may also contain by-product and unreacted starting material. Examples of the by-product include dimers, trimers and higher "homologs" formed by reacting the molecules of the selected bis-epoxide with the desired polyhydric alcohol.

The product mixture obtained from the preparation of the first adduct can, if desired, be added directly to a separate reaction vessel to be reacted in the second stage with the desired amount of the alkylene oxide, e.g. propylene oxide. Alternatively, the alkylene oxide can be introduced directly into the reaction vessel containing the adduct product mixture.

The alkylene oxide reactant for use in the oxyalkylation of the bis-epoxide/polyhydric alcohol adduct product mixture thus formed may comprise alkylene oxides having 2 to 10, preferably 2 to 5, carbon atoms, provided that the demulsifier prepared therefrom contains at least 40% by weight of oxyalkylene units derived from alkylene oxides having 3 carbon atoms or more. Examples of such alkylene oxides are ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, 1,2-epoxypentane, 2,3-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 1,2-epoxy-3-methylbutane and the like Particularly preferred alkylene oxides are propylene oxide and butylene oxide. Most preferably, the alkylene oxide comprises propylene oxide.

The amount of alkylene oxide introduced into the second reaction stage to react with the adduct can vary widely, but preferably 0.1 to 20 parts by weight of alkylene oxide, more preferably 0.4 to 10 parts by weight of alkylene oxide, and most preferably 1 to 4 parts by weight of alkylene oxide are reacted with the adduct product mixture, based on the part by weight of the first adduct product mixture. Preferably, the alkylene oxide introduced into this reaction stage comprises less than about 50% by weight, more preferably less than about 40% by weight, and most preferably less than about 30% by weight (e.g., 0 to 20% by weight) of ethylene oxide, with the balance of the alkylene oxide introduced comprising propylene oxides and higher epoxides as described above. Contact of the selected alkylene oxide and the first adduct reaction mixture is under conditions to react the alkylene oxide with the hydroxy groups of the first adduct. The conditions effective to achieve such reaction can vary widely, and this second stage reaction typically employs a reaction temperature within the range of 110°C to 180°C, preferably 130°C to 160°C. Any convenient pressure can be used, that is, subatmospheric, atmospheric or superatmospheric pressure, although superatmospheric pressure is typically preferred.

A mixture of alkylene oxides may be used, e.g. a mixture of ethylene oxide and a higher alkylene oxide (e.g. propylene oxide or butylene oxide). Alternatively, different alkylene oxides may be introduced in any order to form "blocks" of the separately introduced alkylene oxide. The order of such sequential oxyalkylation or the number of repetitions of each such oxyalkylation may be widely varied. For example, the first adduct may be oxyethylated followed by introduction of propylene oxide for oxypropylation, or the first adduct may be treated first with propylene oxide followed by oxyethylation. of the oxypropylated adduct. When such sequential alkylations with ethylene oxide are used, propylene or higher alkylene oxide is preferably introduced second (if two alkylation steps are used) or last (in the case of three or more alkylation steps) to alkoxylate substantially all of the oxyethylene chain ends.

The reaction of the selected bis-epoxide and the polyhydric alcohol and the alkoxylation of the resulting adduct are preferably carried out under essentially anhydrous conditions.

The oxyalkylation reaction step(s) may be carried out in the presence of the Lewis base catalyst used to form the first adduct, so that it is not necessary to remove the Lewis base catalyst prior to introducing the alkylene oxide. Similarly, the oxyalkylation may be carried out in the presence of the same or a different solvent as in the first reaction in which the first adduct of the epoxide and polyhydric phenol is formed. If desired, additional solvent for the reaction (e.g., toluene) may be added. The Lewis base catalyst is preferably neutralized (e.g., by adding acetic acid or similar alkanoic acids) to a substantially neutral pH (e.g., a pH of 5 to 8).

The demulsifiers of the invention contain at least 40 wt.% of the oxyalkylene units derived from the alkylene oxides having 3 or more carbon atoms (e.g. propylene oxide, butylene oxide and the like) used in the oxyalkylation step.

One of the preferred demulsifiers of this invention can be described as a propoxylated copolymer of a diglycidyl ether of bisphenol A with polypropylene glycol, wherein the polypropylene glycol has a molecular weight of 2,000 to 8,000, the weight ratio of the polypropylene glycol to the diglycidyl ether of bisphenol A is in the range of 14:1 to 18:1, and the weight ratio of propylene oxide reacted with the first adduct is in the range of about 2.5:1 to 3.5:1.

Compatibility Additive C

Preferably, the lubricating oil additive mixtures of the invention further comprise a compatibilizing effective amount of at least one alcohol ester or hydroxyamide derivative of a mono- or polycarboxylic acid having a total of 24 to 90 carbon atoms and at least about 1, e.g. about 2 to 3, carboxylic acid group(s) per molecule. These ester compatibility additives are generally derived from the esterification of a mono- or dicarboxylic acid with a mono-, di- or trihydric alcohol (e.g. glycol, glycerin, oxa-alkanediols). Such esters have previously been used in lubricating oils as friction modifiers, and methods for their preparation and their structures are described in US-A-3,429,817, US-A-4,459,223, US-A-4,479,883, US-A-4,617,026 and US-A-4,683,069. The hydroxyamide derivatives of such mono- or dicarboxylic acids can be prepared by reacting the acid at elevated temperature with a hydroxyamine (e.g., alkanolamines or amino alcohols such as ethanolamine, diethanolamine, propanolamine, 3-amino-1,1-propanediol) using the methods disclosed in US-A-4,557,846.

The carboxylic acid can be an aliphatic, saturated or unsaturated carboxylic acid and generally has a total of 24 to 90, preferably 24 to 60 carbon atoms and at least 1, e.g. 2 to 3, preferably about 2 carboxylic acid groups with at least about 9 carbon atoms, preferably 12 to 42, especially 16 to 22 carbon atoms between the carboxylic acid groups. Examples of the hydroxyamide compatibilizers are oil-soluble hydroxyamide compounds with the formula

J¹-[- N(H)n₄(Z)n₅]n₆ (XIIa)

, in which J¹ is the hydrocarbon radical or the skeleton of a dimer carboxylic acid with a total of 24 to 90 carbon atoms and 9 to 42 carbon atoms between the carboxylic acid groups, Z (a) a hydroxy-substituted alkyl group with 1 to 20 carbon atoms or (b) an oxyalkylene group with the formula

(H-HO)n7-H (XIIb)

wherein A and E are each alkyl groups having 1 to 2 carbon atoms or hydrogen, and n₇ is an integer of 1 to 50, n₄ is 0 or 1, n₅ is 1 or 2, and n₆ is 1 or 2.

Preferred compatibilizers include partial esters or diesters of dicarboxylic acids having the formulas:

HO-J'-OOC-J-COOH (XIIIa) and

HO-J'-OOC-J-COOJ"-OH (XIIIb)

where J is the hydrocarbon radical of the acid and J' and J" are either the hydrocarbon radical of an alkanediol or the oxyalkylene radical of an oxa-alkanediol as defined below. Generally, 1 to 3 moles of glycol, preferably 1 to 2 moles of glycol, are used per mole of acid to give a complete or partial ester.

Esters can also be obtained by esterification of a mono- or dicarboxylic acid or a mixture of such acids with a mixture of diols, in which case J would then be the hydrocarbon radical of the dicarboxylic acid(s) and J' and J" the hydrocarbon radicals belonging to the diols.

The compatibility additives are used in amounts ranging from 0.1 to 5 parts by weight, especially 0.5 to 1.5 parts by weight, based on the weight of the component B demulsifier additive in the lubricating oil composition. If desired, larger amounts of the compatibility additive can be used since such polycarboxylic acid glycol esters can also serve as friction modifiers in the lubricating oil composition. Therefore, the compatibility additives are generally used in an amount of 0.0005 to 2, especially 0.001 to 0.25 and most preferably 0.005 to 0.1 wt.%.

Particularly preferred compatibility additives are the dimer acid esters. The term dimer acid as used herein refers to those substituted cyclohexenedicarboxylic acids formed by a Diels-Alder type reaction (which is a thermal condensation) of C₁₈ to C₂₂ unsaturated fatty acids, such as tall oil fatty acids, which typically contain 85 to 90% oleic or linoleic acids. Such dimer acids contain 36 carbon atoms. The dimer acid structure can generally be given as follows:

in which two of the R²³ to R²⁶ groups contain carboxyl groups and two are hydrocarbon groups, depending on how the condensation of the carboxylic acid took place. The carboxyl groups may be -(CH₂)₈COOH, -CH=CH(CH₂)₈COOH, -(CH₂)₇COOH, -CH₂-CH=CH(CH₂)₇COOH, -CH=CH(CH₂)₇COOH, and the hydrocarbon end groups may be represented by CH₃(CH₂)₄-, CH₃(CH₂)₅-, CH₃(CH₂)₅-, CH₃(CH₂)₇-, CH₃(CH₂)₇CH=CH-, CH₃(CH₂)₇CH=CHCH₂- and the like. The dimer of linoleic acid, which is the preferred embodiment, may be represented by the following formula:

The term dimer acid as used herein necessarily includes products containing trimers (and higher homologues), e.g., up to about 24% by weight trimer, but typically about 10% by weight trimer, since, as is well known in the art, the dimerization reaction produces a product containing a trimer acid of approximately three times the molecular weight of the starting fatty acid.

The polycarboxylic acids or dimer acids listed above are esterified with a glycol, the glycol being an alkanediol or oxa-alkanediol having the formula HO(R²⁷CHCH₂O)x1H, in which R²⁷ is H or CH₃ and x¹ is 1 to 100, preferably 1 to 25, with ethylene glycol and diethylene glycol being particularly preferred. A preferred embodiment is the formation of the ester with 1 to 2 moles of glycol per mole of dimer acid or polycarboxylic acid, such as the ester of diethylene glycol with dimerized linoleic acid. Examples of such esters are compounds having the formula (XVI):

in which D is - (O-CH₂CH₂)x,-OH and x' is an integer from 1 to 100.

The preparation and use of the foregoing polycarboxylic acid glycol esters as friction reducing esters (i.e. friction modifiers) is disclosed in US-A-4,505,829.

Metal detergent component D

The metal detergent additives for lubricating oil are also often referred to as rust inhibitors and include the magnesium, calcium or barium salts of sulfonic acids, alkylphenols, sulfurized alkylphenols, alkyl salicylates and naphthenates. Highly basic, i.e. overbased, metal salts are often used as detergents and appear to be particularly susceptible to interactions with the ashless dispersants. Typically, these metal-containing rust inhibitors and detergents are used in lubricating oil in amounts of 0.1 to 10, e.g., 0.1 to 5, weight percent based on the total weight of the lubricating oil composition. Marine diesel lubricating oils typically use such metal-containing rust inhibitors and detergents in amounts of up to 20 weight percent.

Highly basic alkaline earth metal sulfonates are often used as detergents. They are usually prepared by heating a mixture comprising an oil-soluble sulfonate or alkaryl sulfonic acid with an excess of alkaline earth metal compound in excess of that required to completely neutralize all of the sulfonic acid present, followed by reaction of the excess metal with carbon dioxide to form a dispersed carbonate complex to provide the necessary overbasicity. The sulfonic acids are typically obtained by the sulfonation of alkyl-substituted aromatic hydrocarbons such as those obtained from petroleum fractionation by distillation and/or extraction or by alkylation of aromatic hydrocarbons such as those obtained by alkylation of benzene, toluene, xylene, naphthalene, diphenyl and the halogen derivatives such as chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation can be carried out in the presence of a catalyst with alkylating agents containing about 3 to more than 30 carbon atoms, such as haloparaffins, olefins which can be obtained by dehydrogenation of paraffins, polyolefins prepared from ethylene, propylene. The alkaryl sulfonates usually contain about 9 to about 70 or more carbon atoms, preferably about 16 to about 50 carbon atoms per alkyl-substituted aromatic group.

The alkaline earth metal compounds that can be used to neutralize these alkaryl sulfonic acids to provide the sulfonates include the oxides and hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrogen sulfides, nitrates, borates and ethers of magnesium, calcium and barium. Examples are calcium oxide, calcium hydroxide, magnesium acetate and magnesium borate. As noted, the alkaline earth metal compound is used in excess of the amount required to completely neutralize the alkaryl sulfonic acids. Generally, the amount will range from about 100 to about 220%, although it is preferred to use at least 125% of the stoichiometric amount of metal required to completely neutralize.

Various other methods of preparing basic alkaline earth alkaryl sulfonates are known, such as those described in U.S. Patent Nos. 3,150,088 and 3,150,089, in which overbasicity is achieved by hydrolysis of an alkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbon solvent/diluent oil.

A preferred alkaline earth metal sulfonate additive is magnesium (alkyl aromatic sulfonate) having a total alkalinity number according to ASTM D2896 (TBN) in the range of 300 to 400, with the magnesium sulfonate content in the range of 25 to 32 wt.% based on the total weight of the additive system dispersed in mineral lubricating oil.

Neutral metal sulfonates are widely used as rust inhibitors. Alkyl salicylate and naphthenate materials of polyvalent metals are well-known additives to lubricating oil compositions to improve their high temperature performance and to counteract the deposition of carbonaceous material on pistons (US-A-2 744 069). An increase in the alkali reserve of the alkyl salicylates and naphthenates of polyvalent metals can be realized by using alkaline earth metal salts, e.g. calcium salts, of mixtures of C₈-C₂₆ alkyl salicylates and phenolates (see US-A-2 744 069) or by salts of polyvalent metals and alkyl salicylic acids, the acids being obtained by the alkylation of phenols followed by phenolate formation, carboxylation and hydrolysis (US-A-3 704 315) and then converted into highly basic salts by methods well known and used for such transformations. The alkali reserve of these metal-containing rust inhibitors is useful at TBN levels between about 60 and 150. Included in the useful polyvalent metal salicylate and naphthenate materials are methylene and sulfur bridged materials readily derived from the alkyl substituted salicylic or naphthenic acids or mixtures of either or both with alkyl substituted phenols. Basic sulfurized salicylates and a process for their preparation are shown in U.S. Patent No. 3,595,791. Such materials include alkaline earth metal, particularly magnesium, calcium, strontium and barium salts of aromatic acids having the general formula:

HOOC-ArR&sub1; - Xy(ArR₁OH)n (XVII)

, where Ar is an aryl radical with 1 to 6 rings, R₁ is an alkyl group with 8 to 50 carbon atoms, preferably 12 to 30 carbon atoms (optimally about 12), x is a sulfur (-S-) or methylene (-CH₂-) bridge, y is a number from 0 to 4 and n is a number from 0 to 4.

The preparation of the overbased methylene-bridged salicylate phenolate salt is readily accomplished by conventional procedures such as alkylation of a phenol followed by phenolate formation, carboxylation, hydrolysis, methylene bridging by a coupling agent such as an alkylene dihalide followed by salt formation and simultaneous reaction with carbon dioxide. An overbased calcium salt of a methylene-bridged phenol-salicylic acid having the general formula:

with a TBN of 60 to 150 is very useful in this invention.

The sulfurized metal phenolates can be considered as "metal salts of a phenol sulfide", which refers to a neutral or basic metal salt of a compound represented by the general formula (XIX):

wherein x = 1 or 2 and n = 0, 1 or 2; or a polymeric form of such a compound, wherein R28 is an alkyl radical, n and x are each integers from 1 to 4, and the average number of carbon atoms in all R28 groups is at least about 9 to ensure adequate solubility in oil. The individual R28 groups may each contain 5 to 40, preferably 8 to 20 carbon atoms. The metal salt is prepared by reacting an alkylphenol sulfide with a sufficient amount of metal-containing material to impart the desired alkalinity to the sulfurized metal phenate.

Regardless of the method of preparation, the useful sulfurized alkylphenols generally contain 2 to 14 wt.% and preferably 4 to 12 wt.% sulfur, based on the weight of the sulfurized alkylphenol.

The sulfurized alkylphenol can be converted by reaction with a metal-containing material, including oxides, hydroxides and complexes, in an amount sufficient to neutralize the phenol and, if desired, overbase the product to a desired alkalinity by methods well known in the art. Preferred is a neutralization process that uses a solution of the metal in a glycol ether.

The lubricating oil additive blends of the present invention can be incorporated into a lubricating oil in any convenient manner. Thus, these blends can be added directly to the oil by dispersing or dissolving them in the oil at the desired concentration level of ashless dispersant, demulsifier, compatibility additive, or metal detergent (if used). Such mixing with the additional lubricating oil can take place at room temperature or at elevated temperatures. Alternatively, the ashless dispersant, demulsifier, compatibility additive, and metal detergent (if used) can be mixed with a suitable oil-soluble solvent or base oil to form a concentrate which can then be mixed with a lubricating oil base stock to obtain the final formulation. Such concentrates typically contain (based on the active ingredient a.i.) from 3 to 45% and preferably from 10 to 35% by weight of ashless dispersant A, typically from 0.1 to 3% and preferably from 0.05 to 0.3% by weight of demulsifier additive B, (if present) typically from 0.0005 to 2%, preferably from 0.001 to 0.25% and most preferably from 0.005 to 0.1% by weight of compatibility additive C, (if present) typically from 2 to 45% and preferably from 2 to 14% by weight of metal detergent D and typically from 30 to 90%, preferably from 40 to 60% by weight of base oil, based on the weight of the concentrate.

Additive packages according to the invention, ie concentrates containing ashless dispersant, metal detergent, demulsifier and compatibility additive (alone or together with other lubricating oil additives as discussed below, e.g. anti-wear additives, corrosion inhibitors, oxidation inhibitors, etc.) are preferably prepared in the following manner. The ashless dispersant and metal detergent component (in the selected base oil or solvent) are preferably first heated together at elevated temperature (e.g., 70 to 130°C for a sufficient time and with sufficient agitation to intimately contact these components, followed by cooling the dispersant/detergent mixture to 65°C or below, as disclosed in copending EP-A-0 294 096. The selected demulsifier and compatibility additive are mixed separately in a selected base oil or solvent for a sufficient time and under sufficient conditions to intimately contact these components (e.g., 50 to 130°C for 1 to 5 hours with agitation), and then introduced as a mixture into the dispersant/detergent mixture, e.g., at 50 to 130°C with agitation for 1 to 5 hours to provide a The remaining lubricating oil additives can be added (separately or simultaneously) before, during or after mixing the dispersant/detergent mixture with the demulsifier/compatibility additive mixture.

The lubricating oil base stock for the lubricating oil blend is typically adapted to perform a selected function through the incorporation of additional additives to form lubricating oil compositions (i.e., formulations).

Lubricant compositions

The additive blends of the invention possess very good demulsifying properties as measured in a wide variety of environments. Accordingly, the additives are used by incorporation and dissolution in an oily material such as fuels and lubricating oils. When the additive blends of the invention are used in normally liquid petroleum fuels such as middle distillates boiling from 65°C to 430°C, including kerosene, diesel fuels, heating oils, jet fuels, etc., a concentration of Additives are used in the fuel in the range of typically 0.001 to 0.5 and preferably 0.005 to 0.15 wt.%, based on the total weight of the composition.

The additive blends of the present invention find primary use in lubricating oil compositions employing a base oil in which the additives are dissolved or dispersed. Such base oils may be natural or synthetic. Base oils suitable for use in preparing the lubricating oil compositions of the present invention include those conventionally used as crankcase lubricating oils for spark-ignited or compression-ignited internal combustion engines, such as automobile and truck engines, marine and railroad diesel engines, and the like. Advantageous results are also obtained by using the additive blend of the present invention in base oils conventionally used as power transmission fluids and/or adapted for such use, such as automatic transmission fluids, tractor fluids, general purpose tractor fluids and hydraulic fluids, heavy duty hydraulic fluids, power steering fluids, and the like. Gear lubricants, industrial oils, pump oils and other lubricating oil compositions can also benefit from the incorporation of the additive blends of the invention.

These lubricating oil formulations conventionally contain several different types of additives that provide the characteristics required in the formulations. Included in these types of additives are viscosity index improvers, antioxidants, corrosion inhibitors, detergents, dispersants, pour point depressants, antiwear agents, friction modifiers, etc.

In the manufacture of lubricating oil formulations, it is common practice to incorporate the additives in the form of concentrates containing 10 to 80 wt.%, e.g. 20 to 80 wt.% of active ingredient in hydrocarbon oil, e.g. mineral lubricating oil or other suitable solvent. Typically, these concentrates can with 3 to 100, e.g. 5 to 40 wt.% lubricating oil per part by weight of additive package to produce finished lubricants, e.g. crankcase engine oils. The purpose of concentrates is of course to make the handling of the various materials less difficult and cumbersome, as well as to facilitate dissolution or distribution in the final mixture. Thus, a metal hydrocarbon sulfonate or a metal alkyl phenolate is usually used in the form of a 40 to 50 wt.% concentrate, e.g. in a lubricating oil fraction.

The dispersant and demulsifier blends of the present invention, alone or with compatibilizer and metal detergent (if present), are generally used in admixture with a lubricating oil base stock comprising an oil of lubricating viscosity, including natural and synthetic lubricating oils and blends thereof.

Natural base oils include animal and vegetable oils (e.g. castor oil, lard oil), liquid petroleum oils and hydrorefined, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic type. Oils of lubricating viscosity derived from coal or shale are also suitable base oils.

Alkylene oxide polymers and interpolymers and their derivatives, in which the terminal hydroxyl groups have been modified by esterification, etherification, etc., form a further class of well-known synthetic lubricating oils. Examples of these are polyoxyalkylene polymers obtained by polymerizing ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g. methyl polyisopropylene glycol ether with an average molecular weight of 1000, diphenyl ether of polyethylene glycol with a molecular weight of 500 to 1000, diethyl ether of polypropylene glycol with a molecular weight of 1000 to 1500) and their esters with mono- and polycarboxylic acids, for example the acetic acid esters, mixed C3 to C8 fatty acid esters and C13 oxoacid diesters of tetraethylene glycol.

Another class of synthetic lubricating oils includes the esters of dicarboxylic acids (e.g. phthalic acid, succinic acid, alkylsuccinic acids and alkenylsuccinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenylmalonic acids) with a variety of alcohols (e.g. butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

Esters useful as synthetic oils also include those prepared from C5 to C12 monocarboxylic acids and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.

Silicon-based oils such as the polyalkyl, polyaryl, polyalkoxy or polyaryloxysiloxane oils and silicate oils comprise another useful class of synthetic lubricants, they include tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl) silicate, tetra-(4-methyl-2-ethylhexyl) silicate, tetra-(p-tert-butylphenyl) silicate, hexa-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes and poly(methylphenyl)siloxanes. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid) and polymeric tetrahydrofurans.

Unrefined, refined and re-refined oils can be used in the lubricants of the invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retort smoldering, a petroleum obtained directly obtained by distillation, or ester oil obtained directly from an esterification process, may be an unrefined oil without further treatment. Refined oils are similar to unrefined oils except that they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration or percolation, are known to those skilled in the art. Re-refined oils are obtained by similar processes as those used to obtain refined oils and are applied to refined oils which have already been used. Such re-refined oils are also known as reclaimed or reclaimed oils and have often been additionally treated by techniques to remove spent additives and oil degradation products.

The dispersant and demulsifier blends of the present invention can also be used with VI improvers to form multigrade automotive engine lubricating oils. Viscosity modifiers impart high and low temperature operability to the lubricating oil and allow it to remain relatively viscous at elevated temperatures and also exhibit acceptable viscosity or flowability at low temperatures. Viscosity modifiers are generally high molecular weight hydrocarbon polymers including polyesters. The viscosity modifiers can also be derivatized to include other properties or functions such as additional dispersancy properties. These oil-soluble viscosity modifying polymers generally have number average molecular weights of from 10³ to 10⁶, preferably 10⁴ to 10⁶, e.g. B. 20,000 to 250,000, 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 α-olefins and internal olefins which may be straight chain or branched, aliphatic, aromatic, alkylaromatic, cycloaliphatic, etc. They are often made of ethylene with C₃ to C₃₀ olefins, particularly preferred are the polymers of ethylene and propylene. Other polymers can be used, such as polyisobutylenes, homopolymers and copolymers of C₆ and higher α-olefins, atactic polypropylene, hydrogenated polymers and copolymers and terpolymers of styrene, e.g. with isoprene and/or butadiene and hydrogenated derivatives thereof. The molecular weight of the polymer can be reduced, for example by mastication, extrusion, oxidation or thermal degradation, and it can be oxidized and contain oxygen.

The preferred hydrocarbon polymers are ethylene copolymers containing from 15 to 90 weight percent ethylene, preferably from 30 to 80 weight percent ethylene, and from 10 to 85 weight percent, preferably from 20 to 70 weight percent of one or more C3 to C28, preferably C3 to C18, and especially C3 to C8 alpha-olefins. Although not necessary, such copolymers preferably have a degree of crystallinity of less than 25 weight percent as determined by X-ray spectroscopy and differential scanning calorimetry. Copolymers of ethylene and propylene are most preferred. Other α-olefins that are suitable in place of propylene to form the copolymer or that can 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 α-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, the C3-28 alpha-olefin and a non-conjugated diolefin or mixtures of such diolefins may also be used. The amount of 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 VI improvers are generally polymers of esters of ethylenically unsaturated C₃- to C₈-mono- and dicarboxylic acids, such as methacrylic and acrylic acid, maleic acid, maleic anhydride, fumaric acid.

Examples of unsaturated esters that can be used include those of aliphatic saturated monoalcohols having at least one carbon atom and preferably 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 monocarboxylic acids, preferably saturated acids, 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 can be copolymerized with still other unsaturated monomers such as the olefins, e.g. 0.2 to 5 moles of C2 to C20 aliphatic or aromatic olefin per mole of the unsaturated ester or per mole of the unsaturated acid or anhydride, followed by esterification. For example, copolymers of styrene with maleic anhydride esterified with alcohols and reacted with amines are known, e.g. see US-A-3,702,300. Di(hydrocarbon)dithiophosphate metal salts are often used as anti-wear agents and also provide an antioxidant effect. The zinc salts are most widely used in lubricating oil in amounts of 0.1 to 10, preferably 0.2 to 2, weight percent based on the total weight of the lubricating oil composition. They can be prepared by known methods by first forming a dithiophosphoric acid, usually by reacting an alcohol or a phenol with P₂S₅, and then neutralizing the dithiophosphoric acid with a suitable zinc compound.

Mixtures of alcohols may be used, including mixtures of primary and secondary alcohols, the secondary generally to impart improved antiwear properties, the primary giving improved thermal stability properties. Mixtures of the two are particularly useful. In general, any basic or neutral zinc compound may be used, but the oxides, hydroxides and carbonates are commonly used. Commercial additives often contain an excess of zinc because an excess of the basic zinc compound is used in the neutralization reaction.

The zinc di(hydrocarbon)dithiophosphates useful in the invention are oil-soluble salts of di(hydrocarbon)esters of dithiophosphoric acids and can be represented by the following formula:

where R²⁹9 and R³⁹0 are the same or different hydrocarbon radicals having 1 to 18, preferably 2 to 12 carbon atoms and include radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R²⁹9 and R³⁹0 groups are alkyl groups having 2 to 8 carbon atoms. Accordingly, the radicals can be, for example, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, alkyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. To ensure oil solubility, the total number of carbon atoms (i.e., R29 and R30 in Formula XX) in the dithiophosphoric acid is generally about 5 or higher.

The antioxidants useful in this invention include oil-soluble copper compounds. The copper compound can be mixed with the oil (e.g., an oil-soluble copper compound) to disperse copper in an oil-soluble dissolved form. By oil soluble it is meant that the compound is oil soluble in the oil or additive package under normal mixing conditions. The copper may be in the form of copper(I) or copper(II) compounds. The copper may be in the form of the copper di(hydrocarbyl)thio- or dithiophosphates, it being possible for copper to replace zinc in the reactions and compounds described above, although one mole of Cu(I) or Cu(II) oxide may be reacted with one or two moles of the dithiophosphoric acid, respectively. Alternatively, the copper may be added as the copper salt of a synthetic or natural carboxylic acid. Examples include C₁₀ to C₁₈ fatty acids such as stearic or palmitic acid, but unsaturated acids such as oleic acid, or branched chain carboxylic acids such as ethyl stearate, ethyl stearate, or ethyl stearate. B. Naphthenic acids having a molecular weight of about 200 to 500 or synthetic carboxylic acids are preferred because of the better handling properties and solubility properties of the resulting copper carboxylates. Also useful are oil-soluble copper dithiocarbamates of the general formula (R³¹R³²NCSS)nCu, where n is 1 or 2 and R³¹ and R³² are the same or different hydrocarbon radicals having 1 to 18 and preferably 2 to 12 carbon atoms and include radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R³¹ and R³² are alkyl groups having 2 to 8 carbon atoms. Accordingly, the radicals may be, for example, 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. To obtain oil solubility, the total number of carbon atoms (ie, R³¹ and R³²) is generally about 5 or higher. Copper sulfonates, phenolates and acetylacetonates may also be used.

Examples of useful copper compounds are copper (CuI and/or CuII) salts of alkenylsuccinic acids or anhydrides. The salts themselves can be basic, neutral or acidic. They can be prepared by reacting (a) any of the above in the Sections on ashless dispersants, which have at least one free carboxylic acid (or anhydride) group, with (b) a reactive metal compound. Suitable acid (or anhydride) reactive metal compounds include those such as copper(II) or copper(I) hydroxides, oxides, acetates, borates and carbonates, or basic copper carbonate.

Examples of these metal salts are Cu salts of polyisobutenyl succinic anhydride (hereinafter referred to as Cu-PIBSA) and Cu salts of polyisobutenyl succinic acid. Preferably, the selected metal used is in 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 Mn of about 900 to 1,400 and up to 2,500, with a Mn of about 950 being particularly preferred. Particularly preferred of those listed above in the section on dispersants is polyisobutylene succinic acid (PIBSA). These materials may desirably be dissolved in a solvent, such as a mineral oil, and heated in the presence of an aqueous solution (or slurry) of the metal-bearing material. It may be heated to between 70ºC and about 200ºC. Temperatures of 110ºC to 140ºC are quite appropriate. It may be necessary, depending on the salt being prepared, not to allow the reaction to continue at a temperature above about 140ºC for a certain period of time, e.g. 5 hours, as decomposition of the salt may occur.

The copper antioxidants (e.g. Cu-PIBSA, Cu-oleate or mixtures thereof) are generally used in an amount of 50 to 500 ppm by metal weight in the final lubricant or fuel composition.

The copper antioxidants used in the invention are inexpensive and effective in low concentrations and therefore do not add significantly to the cost of the product. The results obtained are often better than those obtained with previously used antioxidants, which are expensive and in higher concentrations have been used. In the amounts used, the copper compounds do not interfere with the performance of the other components of the lubricant composition and in many cases entirely satisfactory results are obtained when the copper compound is the only antioxidant in addition to ZDDP. The copper compounds can be used to replace part or all of the need for adjunct antioxidants. Thus, for particularly severe conditions, it may be desirable to add an adjunct conventional antioxidant. The amounts of adjunct antioxidant required are, however, small, much less than the amount required in the absence of the copper compound.

Although any effective amount of the copper antioxidant may be incorporated into the lubricating oil composition, it is considered sufficient to have an effective amount that provides the lubricating oil composition with an amount of copper antioxidant of about 5 to 500 (particularly 10 to 200, more preferably 10 to 180, and most preferably 20 to 130 (e.g., 90 to 120)) ppm of added copper based on the weight of the lubricating oil composition. Of course, the preferred amount may depend on the quality of the lubricating oil base stock, among other factors.

Corrosion inhibitors, also referred to as anticorrosive agents, reduce the degradation of metallic parts contacted by the lubricating oil composition. Examples of corrosion inhibitors are phosphosulfurized hydrocarbons and the products obtained by reacting a phosphosulfurized hydrocarbon with an alkaline earth metal oxide or hydroxide, preferably in the presence of an alkylated phenol or an alkylphenol thioester and also preferably in the presence of carbon dioxide. Phosphosulfurized hydrocarbons are prepared by reacting a suitable hydrocarbon such as a terpene, a heavy petroleum fraction of a C2 to C6 olefin polymer such as polyisobutylene with 5 to 30 weight percent of a phosphorus sulfide at a temperature in the range of 65 to 315°C for 1/2 to 15 hours.

Neutralization of the phosphosulfurized hydrocarbon may be accomplished in the manner taught in US-A-1,969,324.

Antioxidants reduce the tendency of mineral oils to age during use, which ageing is noticeable through oxidation products such as sludge or varnish-like deposits on metal surfaces and through increased viscosity. Such antioxidants include the alkaline earth metal salts of alkylphenol thioethers with preferably C5 to C12 side chains, calcium nonylphenol sulfide, barium t-octylphenyl sulfide, dioctylphenylamine, phenyl-α-naphthylamine, phosphosulfurized or sulfurized hydrocarbons, etc.

Friction modifiers are used to impart the correct frictional properties to lubricating oil compositions such as automatic transmission fluids.

Representative examples of suitable friction modifiers can be found in U.S. Patent Nos. 3,933,659, which discloses fatty acid esters and amides, 4,176,074, which describes molybdenum complexes of polyisobutenyl succinic anhydride aminoalkanols, 4,105,571, which discloses glycerol esters of dimerized fatty acids, 3,779,928, which discloses salts of alkanephosphonic acid, 3,778,375, which discloses reaction products of a phosphonate with an oleamide, 3,852,205, which describes S-carboxyalkylene(hydrocarbon)succinimide, S-carboxyalkylene(hydrocarbon)succinamic acid, and mixtures thereof, 3,879,306, which describes N-(hydroxyalkyl)alkenyl succinamic acids or succinimides, 3,932,290 which discloses reaction products of di-(lower alkyl)phosphites and epoxides and 4,028,258 which describes the alkylene oxide adduct of phosphosulfurized N-(hydroxyalkyl)-alkenyl succinimides. The most preferred friction modifiers are glycerol mono- or dioleates and succinate esters or their metal salts of hydrocarbyl-substituted succinic acids or anhydrides and thiobisalkanols as described in U.S. Patent No. - 4,344,853.

Pour point depressants reduce the temperature at which the liquid flows or can be poured. Such additives are well known. Typical of those additives which usefully optimize the low temperature fluidity of the fluid are C8 to C18 dialkyl fumarate-vinyl acetate copolymers, polymethacrylates and paraffin naphthalene.

Foaming can be controlled by a polysiloxane type antifoam agent, such as silicone oil and polydimethylsiloxane.

Organic oil-soluble compounds useful in this invention as rust inhibitors include nonionic surfactants such as polyoxyalkylene polyols and their esters, and anionic surfactants such as salts of alkyl sulfonic acids. Such antirust compounds are known and can be prepared by conventional means. Nonionic surfactants useful in the oily compositions of the invention usually owe their surface active properties to a number of weakly stabilizing groups such as ether linkages. Nonionic antirust agents containing ether linkages can be prepared by alkoxylating organic substances containing active hydrogen with an excess of lower alkylene oxides (such as ethylene or propylene oxide) until the desired number of alkoxy groups are incorporated into the molecule.

The preferred rust inhibitors are polyoxyalkylene polyols and derivatives thereof. These classes of materials are commercially available from several sources: Pluronic polyols from Wyandotte Chemicals Corporation; Polyglycol 112-2, a liquid triol derived from ethylene oxide and propylene oxide available from Dow Chemical Co.; and Tergitol, dodecylphenyl or monophenyl polyethylene glycol ethers, and Ucon, polyalkylene glycols and derivatives, both available from Union Carbide Corp. These are just a few of the commercial products useful as rust inhibitors in the improved compositions of the present invention.

In addition to the polyols themselves, their esters, which are obtained by reacting the polyols with various carboxylic acids, are also suitable. To produce these esters Useful acids are lauric acid, stearic acid, succinic acid and alkyl- or alkenyl-substituted succinic acids in which the alkyl or alkenyl group contains up to 20 carbon atoms.

The preferred polyols are prepared as block polymers. Thus, a hydroxy-substituted compound, Q-(OH)n8 (where n8 is 1 to 6 and Q is the residue of a mono- or polyhydric alcohol, phenol, naphthol, etc.) is reacted with propylene oxide to form a hydrophobic base. This base can then be reacted with ethylene oxide to provide a hydrophilic portion, resulting in a molecule having both hydrophobic and hydrophilic moieties. The relative sizes of these moieties can be adjusted by controlling the ratio of reactants and the reaction time, as will be apparent to those skilled in the art. It is therefore within the state of the art to produce polyols whose molecules are characterized by hydrophobic and hydrophilic groups present in a ratio that makes the rust inhibitors suitable for use in any lubricant composition, regardless of differences in the base oils and the presence of other additives.

If greater oil solubility is required in a given lubricant composition, the hydrophobic portion can be increased and/or the hydrophilic portion can be decreased. If greater ability to break oil-in-water emulsions is required, the hydrophilic and/or hydrophobic portions can be adjusted to accomplish this.

Compounds illustrating Q-(OH)n8 include alkylene polyols such as the alkylene glycols, alkylene triols, alkylene tetrols, etc., such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitol, mannitol and the like. Aromatic hydroxy compounds such as alkylated mono- or polyhydric phenols and naphthols may also be used, e.g., heptylphenol, dodecylphenol.

Other suitable demulsifiers include the esters disclosed in US-A-3,098,827 and US-A-2,674,619.

The liquid polyols sold by Wyandotte Chemical Co. under the name Pluronic Polyols and other similar polyols are particularly suitable as rust inhibitors. These Pluronic Polyols correspond to the formula:

where z, z' and z" are integers greater than 1 such that the -CH₂CH₂O- groups constitute 10 to 40 wt.% of the total molecular weight of the glycol, the average molecular weight of the glycol being 1,000 to 5,000. These products are prepared by first condensing propylene oxide with propylene glycol to form the hydrophobic base material

This condensation product is then treated with ethylene oxide to add hydrophilic moieties to both ends of the molecule. To achieve the best results, the ethylene oxide units should constitute 10 to 40% by weight of the molecule. The products in which the molecular weight of the polyol is 2,500 to 4,500 and the ethylene oxide units constitute 10 to 15% by weight of the molecule are particularly suitable. The polyols with a molecular weight of 4,000, in which about 10% is due to (CH₂CH₂O) units, are particularly good. Also useful are alkoxylated fatty amines, amides, alcohols and the like, including those alkoxylated fatty acid derivatives treated with C9 to C16 alkyl substituted phenols (such as the mono- and di-heptyl, octyl, nonyl, decyl, undecyl, dodecyl and tridecyl phenols) as described in US-A-3,849,501.

The compositions according to the invention may also contain other additives, such as those described above, and further metal-containing additives, for example those containing barium or sodium.

The lubricant compositions of the present invention may also include copper-lead bearing corrosion inhibitors. Typically such compounds are the thiadiazole polysulfides having from 5 to 50 carbon atoms, their derivatives, and polymers thereof. Preferred materials are the derivatives of 1,3,4-thiadiazoles such as those described in U.S. Patent Nos. 2,719,125, 2,719,126, and 3,087,932, particularly preferred is the compound 2,5-bis(t-octadithio)-1,3,4-thiadiazole, which is commercially available as Amoco 150. Other similar materials that are also suitable are described in U.S. Patent Nos. 3,821,236, 3,904,537, 4,097,387, 4,107,059, 4,136,043, 4,188,299 and 4,139,882.

Other suitable additives are the thio- and polythiosulfenamides of thiadiazoles such as those described in UK-A-1 560 830. When these compounds are included in the lubricating oil composition, we prefer that they be present in an amount of from 0.01 to 10, preferably from 0.1 to 5.0% by weight, based on the weight of the composition.

Some of these numerous additives can provide several of these effects, e.g. a dispersant-oxidant. This approach is well known and does not need to be further elaborated here.

Compositions containing these conventional additives are typically blended with the base oil in amounts effective to provide their normal, expected function. Representative effective amounts of such additives (as the corresponding active ingredient ai) in the fully formulated oil are illustrated as follows: Compositions Wt.% ai (preferred) Wt.% ai (general) Ashless dispersant (component A) Polymeric viscosity index improver (component A) Demulsifier (component B) Compatibilizer (component C) Metal detergent (component D) Viscosity index modifier Corrosion inhibitor Oxidation inhibitor Pour point depressant Antifoam agent Antiwear agent Friction modifier Mineral oil base substance Difference up to 100%

When additional additives are used, it may be desirable, although not necessary, to prepare additive concentrates comprising concentrated solutions or dispersions of the novel ashless dispersant and demulsifier blends of the present invention (in the concentration ranges described above) together with one or more additional additives (including metal detergent, compatibilizer, etc.) (the concentrate, when comprising a blend of additives, is referred to herein as an additive package), whereby multiple additives can be added simultaneously to the base oil to form the lubricating oil composition. Dissolution of the additive concentrate in the lubricating oil can be facilitated by solvents and by mixing with gentle heating, but this is not essential. The concentrate or additive package will typically be formulated to contain the additives in appropriate amounts to achieve the desired concentrations in of the final formulation when the additive package is combined with a predetermined amount of base lubricant. Accordingly, the dispersants of the invention, together with other desirable additives, can be added to small amounts of base oil or other compatible solvents to form additive packages containing active ingredients in total amounts of typically 2.5 to 90%, preferably 15 to 75%, and most preferably 25 to 60% by weight of additives in appropriate proportions, the balance being base oil.

The final formulations can typically use about 10 wt% of the additive package, with the remainder being base oil.

All weight percentages quoted here (unless otherwise stated) refer to the active ingredient (a.i.) content of the additive and/or to the total weight of any additive package or formulation, which consists of the sum of the a.i. weights of each additive plus the weight of the total oil or diluent.

This invention will be further understood by reference to the following examples in which all parts are by weight unless otherwise indicated and which include preferred embodiments of the invention.

Examples

A series of test lubricating oil formulations were prepared containing ashless dispersant, metal detergent, viscosity modifier and the demulsifiers of the invention or other test materials identified in Tables I and II below. To measure the crankcase pressure generated, the indicated compositions were tested in an abbreviated version of the Sequence IID test (referred to as the IID Screener) in which the ASTM Sequence IID procedure was followed for 12 hours using an Oldsmobile V8 engine that was not rebuilt but instead was thoroughly flushed between runs. Crankcase pressure was monitored during these 12 hours to obtain an integrated (cumulative) crankcase pressure value. The values thus obtained are summarized in Table III. This test can thus be used to predict the tendency of lubricating oils to form emulsions and generate crankcase pressure in the IID sequence. Table I: Formulations Component % by weight ai Ashless dispersant(1) Metal detergent(2) Demulsifier Base oil(3) (See Table III) as remaining component

Remarks:

(1) Borated polyisobutenyl succinimide (PIB n = 2200) of polyethylene polyamine (2) overbased magnesium sulfonate detergent TBN=400 (3) Solvent (about 130) neutral mineral base oil which also contained copper antioxidant, zinc dialkyldithiophosphate antiwear agent and ethylene-propylene copolymer viscosity index improver. Table II - Demulsifiers Example No. Demulsifier (1) EO:PO weight ratio (2) Alkylene oxide:adduct weight ratio (3) Propoxylated adduct of polypropylene glycol and diglycidyl ether of bisphenol A Ethoxylated propoxylated adduct of polypropylene glycol and diglycidyl ether of bisphenol A

Remarks:

(1) Polypropylene glycol, average molecular weight = 5000

(2) EO = ethylene oxide, PO = propylene oxide, weight ratio based on ethylene oxide and propylene oxide reacted with polypropylene glycol/diglycidyl ether of bisphenol-A adduct (“adduct”).

(3) Alkylene oxide:adduct ratio, based on the weight of alkylene oxide and adduct charged. Table III Example No. Demulsifier Integrated Crankcase Pressure, Units Comparison Prepared as in Example Polypropylene glycol(1) Polypropylene glycol/diglyceridyl ether adduct(2) None

Remarks:

(1) corresponds to the polypropylene glycol used as feedstock for Example 1.

(2) Prepared as in Example 1(a)

(3) Composition as in Table I without added demulsifier

The pressure values in Table III show that the surprisingly reduced crankcase pressure results from the use of the demulsifiers of the invention of Examples 4 to 11, compared to the polypropylene glycol and polypropylene glycol/diglycidyl ether adduct in Comparative Examples A and B, respectively, and compared to the significantly higher crankcase pressure shown by the comparison without demulsifier (Comparative Example C). The propoxylated demulsifiers of Examples 1 and 2 provided a particularly greatly reduced crankcase pressure and were superior in this respect to the demulsifier of Example 3, which contained equal proportions of oxyalkylene units derived from ethylene oxide and propylene oxide. Comparative Example B illustrates how critical the alkoxylation step is. in the preparation of the demulsifiers according to the invention.

Without wishing to be bound by theory, it is believed that the alkoxylation step serves both to extend the chain of the bis-epoxide-polyhydric alcohol adduct by the addition of oxyalkylene groups to the chain ends of the adduct, and to alkoxylate the hydroxy groups in the adduct formed by ring opening of the epoxy groups of the bis-epoxide, some of which, however, are not further reacted during the adduct preparation step.

Examples 12 to 18

In a separate series of tests, additive packages for crankcase lubricating oils were prepared with the following components shown in Table IV. Each additive package was kept at 66ºC and observed to determine the onset of haze formation, which is an indicator of the stability of the additive package. The values obtained are summarized in Table V below. Table IV: Additive concentrates Component Ashless dispersant(1) Metal detergent(2) Demulsifier Compatibility additive(3) Base oil(4) (see Table V) as remaining component

Remarks:

(1) Borated polyisobutenylsuccinimide (PIB n = 2200) of polyethylenepolyamine

(2) overbased magnesium sulfonate detergent, TBN = 400

(3) Diethylene glycol esters of dimers and trimers of linoleic acid

(4) Solvent (about 130) neutral mineral base oil which also contained copper antioxidant, zinc dialkyldithiophosphate antiwear agent and ethylene-propylene copolymer viscosity index improver and additionally nonylphenol sulfide antioxidant. Table V Demulsifier Stability of additive package at 66ºC Compatibility additive (wt.%) Example No. prepared as in example wt.% Number of days Appearance none Turbidity OK slight turbidity

The data in Table V illustrate the improved stability of the additive package observed using the demulsifiers and compatibility additive of the invention. Significant improvements in terms of reduced haze were achieved when the propoxylated demulsifier of Example 2 was used, in which a propylene oxide to adduct weight:weight ratio of 0.6:1 was used in combination with a compatibility additive of the invention. No haze appeared in the additive package of Example 13 even after 96 days of storage at 66°C, although haze was observed after 5 days in Example 12. Similar improvements in haze appearance are shown using the propoxylated demulsifier of Example 1 at a PO:adduct ratio of 3:1 in combination with a compatibility additive of the invention, as can be seen by comparing Example 15 with the additive package of Example 14, where no compatibility additive was used, and by comparing Examples 17 and 18 (which use various amounts of the compatibility additive) with the additive package of Example 16.

Examples 19 to 24

In separate experiments, series of lubricating oil concentrates ("additive packages") were prepared by mixing 10 parts S150N lubricating oil, 55 parts ashless dispersant (polyisobutenyl succinimide of a polyethylene containing about 7 carbon atoms and 5 to 6 nitrogen atoms per polyamine molecule) and 11 parts metal detergent additive (overbased magnesium sulfonate, TBN=400) for 3 hours at a temperature of 100ºC. Equal parts of each mixture were then taken and checked to see if they were free of any visible turbidity or sediment.

Each blend was cooled to a temperature of 75ºC and then the following additional components were introduced with the indicated components used in each blend at the same concentrations: zinc dialkyldithiophosphate antiwear agent, nonylphenol sulfide antioxidant and copper antioxidant to form a partial additive package (95.3 parts).

To each partial additive package (at 75ºC) was added a selected amount of demulsifier and compatibility additive of the invention together with sufficient lubricating oil to make up the balance to 100 parts by weight of the lubricating oil concentrate. The order of mixing these additional components was varied as follows:

Procedure A

The additional required base oil, the demulsifier from Example 1 and the specified compatibility additive were separately added to the partial additive package with stirring for 1.5 hours at 75ºC.

Procedure B-1

The additional required base oil, the demulsifier from Example 1 and Compatibility Additive I were first premixed for one hour at 75ºC and the resulting premix was introduced into the partial additive package with additional stirring for 1.5 hours at 75ºC.

Procedure B-2

The additional required base oil, the demulsifier from Example 1 and compatibility additive II were first premixed at 75ºC for one hour and the resulting premix was introduced into the partial additive package with additional stirring for 1.5 hours at 75ºC.

The appearance of each lubricating oil concentrate was then checked and equal amounts were held at either 54ºC or 66ºC for an extended period of time to check the appearance and determine the onset of clouding or other signs of instability of the blends. The results obtained are shown in Table VI below: Table VI Compatibility Additive (3) Storage stability on day No. Example No. added base oil (parts) (1) demulsifier (2) (parts) parts mixing process at ºC Turbidity after OK after

Remarks:

(1) S150N Lubricating oil

(2) as in Example 1: propoxylated adduct of polypropylene glycol and diglycidyl ether of bisphenol A

(3) I = glycerol monooleate, II = diethylene glycol ester of linoleic acid dimer

The above values illustrate the improved storage stability achieved by premixing the demulsifiers and the compatibility additives of the invention before contacting the demulsifier with the remaining components of the additive package, as compared to the use of equivalent amounts of the demulsifier and compatibility additive without such premixing. The shelf life achieved by premixing the demulsifier with the linoleic acid dimer glycol ester additive in Example 22 (as compared to the results achieved in Example 19 without such premixing) is particularly surprising in view of the prior art recognition that instability problems have previously been observed from the use of such esters as friction modifiers. Increased shelf life also results from premixing the demulsifier with a higher concentration of the linoleic acid dimer glycol ester additive in Example 23 and by premixing with the same higher concentration of the glycerin monooleate additive in Example 24, as compared to the results achieved in Example 21 without any premixing.

Claims (23)

1. Oil-soluble mixture which is useful as an oil additive and (A) ashless lubricating oil additive which (1) ashless dispersants selected from (i) oil soluble amine salts, amides, imides, oxazolines and esters or mixtures thereof of long chain hydrocarbon substituted mono- and dicarboxylic acid material, i.e. acid, anhydride or ester, (ii) a long chain aliphatic hydrocarbon group having a polyamine directly attached thereto, and (iii) Mannich condensation products formed by condensing about one molar proportion of long chain hydrocarbon substituted phenol with 1 to 2.5 moles of formaldehyde and 0.2 to 2 moles of polyalkylenepolyamine, wherein the long chain hydrocarbon group in (i), (ii) or (iii) is a polymer of a C₂ to C₁₀ monoolefin and said polymer has a number average molecular weight of at least 900, (2) a polymeric viscosity index improver dispersant selected from (i) polymers composed of unsaturated C4 to C24 esters of vinyl alcohol or unsaturated C3 to C10 mono- or dicarboxylic acid and unsaturated nitrogen-containing monomers having 4 to 20 carbon atoms, (ii) polymers of C2 to C20 olefin and unsaturated C3 to C10 mono- or dicarboxylic acid neutralized with amine, hydroxyamine or alcohols, and (iii) polymers of ethylene and a C3 to C20 olefin further reacted by reacting unsaturated nitrogen-containing C4 to C₂₀ monomers were grafted thereon or by grafting an unsaturated acid onto the polymer backbone and then the carboxylic acid groups were reacted with amine, hydroxyamine or alcohol, and mixtures of (A)(1) and (A)(2), and (B) demulsifier additive, characterized in that the demulsifier additive (B) is the reaction product of (i) alkylene oxide having 2 to 10 carbon atoms and (ii) an adduct obtained by reacting polyhydric alcohol with bis-epoxide containing at least two oxirane rings linked by a C₁-C₁₀₀₀ hydrocarbon group, wherein the hydrocarbon group optionally contains (a) one or more alkyl groups, tertiary amino groups and halogens as substituents and/or one or more oxygen atoms, sulfur atoms, carboxy groups, sulfonyl groups, sulfinyl groups, ketone groups, oxirane rings and nitro groups in the carbon chain which are separated from the carbon atom of the oxirane ring by at least one intervening carbon atom, and the demulsifier contains at least 40% by weight of the oxyalkylene units derived from the alkylene oxides having 3 or more carbon atoms. 2. An oil-soluble mixture according to claim 1, wherein the bis-epoxide comprises the diglycidyl ether of bisphenol A. 3. An oil-soluble mixture according to claim 1 or claim 2, wherein the alkylene oxide component (i) of the demulsifier additive is propylene oxide. 4. Oil-soluble mixture according to claim 3, wherein the demulsifier additive comprises oxyalkylation units derived from butylene oxide. 5. An oil-soluble mixture according to any one of claims 1 to 4, wherein the polyhydric alcohol comprises polyoxyalkylene glycol. 6. An oil-soluble mixture according to claim 5, wherein the polyoxyalkylene glycol has a number average molecular weight of 1,000 to 10,000. 7. An oil-soluble mixture according to claim 6, wherein the polyoxyalkylene glycol comprises polypropylene glycol. 8. An oil-soluble mixture according to claim 7, wherein the polypropylene glycol has a number average molecular weight of 2,000 to 8,000. 9. The oil-soluble mixture of any one of claims 1 to 8, wherein the ashless additive comprises the reaction product of a hydrocarbon-substituted C4 to C10 monounsaturated dicarboxylic acid material formed by reacting a C2 to C10 monoolefin polymer having a number average molecular weight of at least 900 with a C4 to C10 monounsaturated acid material having at least an average of 0.8 dicarboxylic acid producing groups per molecule of olefin polymer present in the reaction mixture to form the acid material, and (b) a nucleophilic reactant selected from the group consisting of amines, alcohols, amino alcohols, and mixtures thereof. 10. The oil-soluble reaction mixture of claim 9 wherein the nucleophilic reactant comprises polyalkylenepolyamine wherein the alkylene groups contain from 2 to 40 carbon atoms and the polyalkylenepolyamine contains from 2 to about 9 nitrogen atoms per molecule. 11. An oil-soluble mixture according to claim 10, wherein the olefin polymer is polyisobutylene having an average molecular weight (number average) from 1,500 to 3,000 and the monounsaturated acid material is maleic anhydride. 12. Oil-soluble mixture according to one of claims 1 to 11, in which the oil-soluble mixture additionally contains at least one metal detergent additive (D) which comprises at least one magnesium, calcium or barium salt of a material selected from the group consisting of sulfonic acids, alkylphenols, sulfurized alkylphenols, sulfurized alkylphenols, alkyl salicylates and naphthenates. 13. Oil-soluble mixture according to one of claims 1 to 12, which additionally contains 0.1 to 5 parts by weight of at least one compatibility additive (C) based on (B), wherein (C) is an ester or hydroxyamide derivative of a mono- or polycarboxylic acid having a total of 24 to 90 carbon atoms and at least about 1 carboxylic acid group per molecule with a mono-, di- or trihydric alcohol. 14. An oil-soluble mixture according to claim 13, wherein the compatibility additive comprises a glycol ester having 2 to 3 carboxylic acid groups per molecule. 15. Oil-soluble mixture according to claim 14, wherein the compatibility additive comprises at least one partial ester or diester with the formulas HO-J'-OOC-J-COOH or HO-J'-OOC-J-COOJ"-OH in which J is the hydrocarbon radical of an aliphatic, saturated or unsaturated polycarboxylic acid with a total of 24 to 90 carbon atoms, 2 to 3 carboxylic acid groups per molecule and at least 9 carbon atoms between the carboxylic acid groups, and J' and J" are the same or different and each comprise the hydrocarbon radical of an alkanediol or an oxyalkylene radical. 16. Oil-soluble mixture according to one of claims 13 to 15, in which the compatibility additive is used in an amount of 0.5 to 1.5 parts by weight, based on the total weight of the demulsifier additive (B) in the oil-soluble mixture. 17. An oil-soluble mixture according to claim 13, wherein the compatibility additive comprises at least one ester of a substituted cyclohexenedicarboxylic acid formed by a thermal Diels-Alder condensation of C₁₈ to C₂₂₀ unsaturated fatty acids. 18. An oil-soluble mixture according to claim 17, wherein the unsaturated fatty acid comprises oleic acid, linoleic acid or a mixture thereof. 19. An oil-soluble mixture according to claim 18, wherein the compatibility additive is an ester having the formula in which D is - (O-CH₂CH₂)x,-OH and x' is an integer from 1 to 100. 20. Lubricating oil additive concentrate containing 10 to 80% by weight of oil-soluble mixture according to one of the preceding claims dissolved in a hydrocarbon oil. 21. Concentrate according to claim 20, which 3 to 45 wt.% of the ash-free dispersant (A)(1), 0.01 to 3 wt.% of the demulsifier additive (B), 0.0005 to 2 wt.% of the compatibility additive (C) and 2 to 45 wt.% of the metal detergent additive (D). 22. A process for forming a concentrate according to claim 20 or 21, wherein the ashless dispersant (A)(1) and the metal detergent component (D) are premixed at 70 to 130°C and the demulsifier additive (B) and the compatibility additive (C) are mixed separately, and the separate mixtures are then mixed together. 23. A lubricant composition comprising a concentrate according to claim 20 or 21 or obtainable according to the process of claim 22 diluted with 3 to 100 parts by weight (per part by weight of concentrate) of lubricating oil.