These low-ethylene copolymers, in conjunction with viscosity modifiers, provide advantageous and improved low temperature performance properties to the oil.

Background of the Invention Multigrade crankcase lubricants (e.g., SAE 5-W-30 grade, 10-W-30 and 15- W-40 motor oils) must simultaneously meet a minimum high temperature (kinematic) viscosity and a maximum low temperature (dynamic) viscosity specification. Various polymeric additives, such as dispersants and viscosity modifiers, have been used to enhance the performance of these lubricants. At a given temperature, the viscosity enhancement provided by a polymeric additive is a complex function of the molecular weight of the polymer, molecular weight distribution, the concentration of the polymer and the interaction of the polymer with other additives and the base stock used, and the wax contained in the basestock. Dispersants, for example, typically have oil soluble polymeric hydrocarbon backbones. These backbones contain functional groups that are capable of associating with combustion by-products in engine oil that must be dispersed for optimal performance. Typically, the dispersant has amine, alcohol, amide, or ester polar moieties attached to the polymer backbone, often via a bridging group. Viscosity modifiers, another common type of additive, are used to impart high and low temperature operability to a lubricating oil. Furthermore, viscosity modifiers may have dispersancy properties. Typically, both dispersants and viscosity modifiers are used in an engine oil lubricant.

Currently, the principal viscosity modifiers used in lubricating oil formulations are hydrocarbon copolymers. These include, for example, ethylene-propylene copolymers (EP), hydrogenated diene polymers and hydrogenated diene styrene copolymers (for example, hydrogenated isoprene styrene copolymers (HIS)) and polyacrylate or polymethacrylate polymers, for example, polyalkylmethacrylates (PMA).

In lubricating oils, polyisobutene- or polyisobutylene-based dispersants have been the most commercially significant, but they suffer from a variety of drawbacks, primarily related to their behavior and performance at low temperatures. The polyisobutylene backbone appears to be unable to adjust and change its conformation

in the manner of more flexible backbone chains such as ethylene alpha-olefin (e.g., ethylene-propylene, ethylene-i -butene) copolymers. Hence, ethylene alpha-olefin copolymer dispersants have certain advantages over polyisobutenes. However, the polyethylene segments present in an ethylene alpha-olefin copolymer are more crystalline and, if present at a high enough concentration, may cause the copolymers to associate with each other. They may also cause the copolymers to associate with other components in the additive package and with the wax contained in the base oil, resulting in low temperature viscosity problems.

This invention resolves these difficulties by providing an ethylene alpha-olefin copolymer dispersant having a lower weight percent ethylene content than is taught or suggested as beneficial by the art. In cooperation with viscosity modifiers such as ethylene alpha-olefin copolymers, polyalkylacrylate polymers, hydrogenated diene polymers, and hydrogenated diene styrene copolymers, a surprising synergism is achieved. This results in improved lubricant oils with improved performance at low temperature, as measured in the cold cranking simulator ("CCS") test. The CCS test is a test of low temperature/high shear viscosity, the results of which are indicative of low temperature engine cranking performance. This viscosity is measured by the cold-cranking simulator at a specified temperature (e.g., for a 5-W-30 oil, at -250C), measured in centipose (cps). Dispersants and viscosity modifiers added to the oil will affect the oil's viscosity as measured by the CCS test. Accordingly, CCS test results are an indirect measure of the influence of polymer type and content on low temperature performance.

Over the years, as lubricants have continuously improved performance, the total amount of additives present in the lubricants has steadily increased. The typical treat rate of API SE, SF, SG and SH oils were 5.5, 6.5, 10 and 13 percent, respectively. However, it is desirable to minimize the contribution of the additives to the maximum low temperature dynamic viscosity. When the dispersant and the viscosity modifiers contribute less overall to CCS viscosity, formulators have more flexibility in selecting components and can use less expensive, higher neutral number basestocks in fully formulated oils.

Ethylene alpha-olefin copolymers are known in the art as lubricating oil additives. Such polymers are typically added to lubricating oils to facilitate the use of low viscosity basestocks. For example, US-A-3697427 discloses a lubricating oil composition comprising a lubricating oil and a viscosity index improving amount of a polymer composition comprising a first copolymer of ethylene and an alpha-olefin and a second copolymer of ethylene and an alpha-olefin wherein the ethylene content of the first copolymer is at least 4 weight percent higher than the ethylene content of

the second copolymer. An improvement in the viscosity index and pour point of the oil is disclosed.

US-A-5427702 discloses mixtures of a higher ethylene, ethylene/propylene copolymer multifunctional viscosity modifier "B" (70 wt. % ethylene) and a lower ethylene-ethylene/propylene copolymer (43 wt. % ethylene) multifunctional viscosity modifier "A", wherein as the amount of "B" is increased in a lubricating oil, an improvement in low temperature performance, as measured by the cold cranking simulator (CCS) test results. Number average molecular weights from about 20,000 to about 100,000 are disclosed for the multifunctional viscosity modifier. Based on the data in figure 1 of this patent, better CCS performance (i.e., lower values) would be expected using a viscosity modifier prepared from higher ethylene content, ethylene/alpha-olefin copolymer backbones.

US-A-5498809 (Emert et al.) discloses ethylene l-butene copolymers having an ethylene content of not greater than about 50 weight percent, wherein the copolymers and dispersant additives produced from the copolymers possess enhanced pour point performance in lubricating oils. Emert et al. neither describes nor suggests the unexpected and synergistic effect that arises when the particular dispersants and viscosity modifiers of the present invention are blended with a lubricating oil, wherein particularly desirable low temperature properties are obtained. US-A-4804794 discloses a copolymer of ethylene and at least one other alpha-olefin monomer useful as a viscosity modifier, comprising intramolecularly heterogeneous copolymer chains containing at least one crystallizable segment containing an average ethylene content of at least 57 weight percent and at least one low crystallinity segment containing an average ethylene content of not greater than about 53 weight percent. The copolymers provide lubricating oils having highly desirable viscosity and pumpability properties at low temperatures. Figure 6 of this patent shows the desirable impact of high ethylene content on CCS.

US-A-5391617 discloses blends of ethylene-propylene polymers which are useful as viscosity index improvers, prepared by simultaneously blending and shearing the polymers to reduce their molecular weight and molecular weight distributions. An essentially amorphous low ethylene content, ethylene-propylene copolymer having 35 to 65 mole percent ethylene and a partially crystalline higher ethylene content, ethylene-propylene copolymer having about 65 to about 85 mole percent ethylene are used. The polymer blends exhibit improved low temperature properties as compared to either of the two polymers used in preparing the blend and blends of the same two polymers prepared by other blending techniques.

EP-A-063861 1 discloses a dimensionally stable polymer blend which is useful

as a viscosity index improver, comprising a partially crystalline ethylene copolymer comprising 60 to 85 mole percent ethylene and an amorphous copolymer comprising 40 to 65 mole percent ethylene. Results in examples VI to IX of this reference show improved (lower) CCS values as the ethylene content of the first, higher ethylene copolymer is increased.

Thus, from the prior art, it would appear that an ethylene alpha-olefin dispersant would show improved CCS viscosity in direct relation to its increasing ethylene content. In these references, better CCS test performance (lower CCS viscosity) was expected of formulations using a dispersant prepared from correspondingly higher ethylene content ethylene alpha-olefin backbone polymers, because a polymer with a high enough molecular weight to enhance an oil's viscosity at high temperatures may have too high a viscosity at low temperature (resulting in low temperature fluidity problems, such as difficult engine cranking and poor engine lubrication).

The present inventors have surprisingly found that, to the contrary, additives containing lower ethylene content (e.g., 39 wt. %) ethylene alpha-olefin copolymers result in better CCS viscosities than those containing higher ethylene content (e.g., 51 wt. %) ethylene alpha-olefin copolymers (e.g., ethylene butene copolymers).

Furthermore, the prior art fails to recognize the synergistic effect disclosed herein of low ethylene, ethylene alpha-olefin dispersants, the specific viscosity modifier selected for use therewith and the basestock environment in which these additives are used. The present inventors have discovered that a lubricating oil with an ethylene alpha-olefin dispersant performs differently depending on the viscosity modifiers selected for use with it. This allows a lubricant formulator more flexibility in the amount and type of additives and base oils (basestocks) that can be used, resulting in cost savings and performance benefits.

This invention also relates to the surprising synergism of these preferred dispersant-preferred viscosity modifier combinations that result in improved lubricant oils with improved performance at low temperature, as measured, for example, by the Mini Rotary Viscometer (MRV), using Temperature Profile 1 (MRV-TP-1)(ASTM D- 4684), and the Scanning Brookfield Viscometer (SBV) (ASTM D-5 133).

The trouble-free operation of an engine during and after starting at low temperatures is achieved by an uninterrupted supply of oil to points of friction, i.e., by the oil's pumpability. A key parameter in pumpability is the wax content of a lubricant's base oil, and in particular its composition, concentration and morphology.

Since the wax characteristics of base oils vary, so does the low temperature performance of the various base oils used by the lubricant formulators. It is important

that a lubricating oil have relatively low viscosities at low temperatures, and that additives are selected that do not contribute to poor low temperatures performance.

In light of the varying low temperature performance of various base oils, it is desirable to minimize the contribution of the lubricant's additives to the low temperature viscosity. Lubricant oil basestocks (hereinafter also referred to as base oils) typically contain paraffinic and isoparaffinic waxy components which are capable of crystallizing. As a basestock is cooled from high temperatures, a temperature is reached at which these wax components begin to crystallize. When the crystals become large they scatter light and make the oil turbid. This is called the "cloud point", which temperature can be determined using the ASTM D-2500 test procedure. Below the cloud point, waxes in the basestock can co-crystallize with crystallizable polymer segments, (either from the viscosity modifier or dispersant) effectively cross linking the polymer molecules. This results in high "effective" polymer molecular weights, or causes "gelation" of the oil as observed by the appearance of a yield stress upon shearing. Such apparent high molecular weights are undesirable, as they increase the oil viscosity at low temperatures making it difficult for the oil to be pumped or poured.

The Society of Automotive Engineers (SAE) has identified two pathways to pumpability problems. In the air-binding condition some oil is pumped out of the oil sump, but oil does not flow or slump toward the oil screen, when the engine is cranked. An air cavity is formed, thus, preventing flow. In the flow-limited condition, the apparent viscosity of the oil is too high to allow it to flow through the pump inlet tube at a sufficient rate to allow for proper lubrication. These modes of failure have resulted in low temperature engine oil pumpability being defined in terms of cooling rate and two rheological properties of an oil, yield stress and apparent viscosity. These physical properties of an oil can be measured by a low shear viscometer, e.g., a Mini Rotary Viscometer. The Scanning Brookfield viscometer also measures the flow properties of an oil. Yield stress is an estimate of the air-binding tendency of an oil and it is a measure of the congealing strength of the wax crystals.

Apparent viscosity is an estimate of the flow limited condition of an oil and it is dependent upon the oil's viscosity at a particular temperature, which is influenced by the concentration of wax, as well as the size, shape and number of wax crystals.

The polymer content derived from both the viscosity modifier and dispersant may also have a negative impact on MRV viscosity and Scanning Brookfield viscosity due to interactions with paraffinic wax from the base stock. Mineral base oils contain some paraffinic wax that is not removed during refining. At low temperatures, there are performance properties that are related to the wax content of

the base oil diluent in a lubricating oil formulation. There are multiple interactions that affect the low temperature tests, namely involving the VM-Dispersant-LOFI and Wax. It appears that, when using a high ethylene, ethylene alpha-olefin dispersant, the dispersant's interactions with the wax and the VM can often be antagonistic and impact performance at low temperatures. Thus, it is important to select viscosity modifiers, dispersants and flow improvers that minimize these interactions.

MRV and SBV are low temperature, low shear tests, while the Cold Cranking Simulator (CCS ASTM D-5293, discussed above) is a low temperature, high shear test. Wax content has a minor role in CCS performance, discussed above, but has a major role in MRV and Scanning Brookfield performance. Multiple interactions, e.g., between the LOFI-wax-viscosity modifier-dispersant, affect these latter low temperature tests. Many of these interactions are antagonistic to low temperature performance. The present invention is directed to improving low temperature performance, in light of the various interactions, through the synergistic use of dispersant, viscosity modifier, and basestock combinations and optionally a preferred LOFI. A lubricating oil formulator with flexibility in the additives that can be chosen for use, having selected a low ethylene, ethylene alpha-olefin dispersant based on CCS improvement and resultant cost savings achievable from basestock substitution, can further improve low temperature performance based on the viscosity modifier, basestock and lubricant flow improver selected for use with the dispersant.

Yet the prior art fails to suggest that a lubricating oil containing a low ethylene, ethylene alpha-olefin dispersant would directionally improve low temperature performance in the key tests such as MRV and Scanning Brookfield.

Further, the prior art fails to recognize the synergistic effect of low ethylene, ethylene alpha-olefin dispersants, and the viscosity modifier selected for use therewith, the basestock environment in which these additives are used and the utility of the lubricant flow improver.

Thus, it has been surprisingly found that certain low ethylene, ethylene alpha- olefin (e.g., ethylene-butene) based dispersants used in combination with these viscosity modifiers and an appropriate Lube Oil Flow Improver (LOFI) allow use of various basestocks and result in lubricant oils having improved low temperature performance, as measured by MRV TP-l and SBV. Improved low temperature performance allows a lubricant formulator more flexibility in the amount and type of additives and basestocks that can be used, resulting in cost saving and performance benefits. For example, use of dispersants and viscosity modifiers with better MRV and SBV performance allows an oil formulator to use less LOFI, which is an expensive additive. Further, it allows a formulator to improve the low temperature

performance of lubricants based on base oils with inferior low temperature performance by virtue of their wax and viscosity characteristics.

Summary of the Invention The present invention relates to a lubricating oil composition exhibiting improved low temperature performance comprising an ethylene alpha-olefin dispersant and a viscosity modifier, wherein the dispersant has an ethylene content in the range of about 10 to 50 weight percent, preferably 30 to 50 weight percent.

The lubricating oil composition may further comprise viscosity modifiers selected from the group consisting of alkylene alpha-olefin copolymers, polyalkylacrylate polymers, hydrogenated diene polymers, hydrogenated diene styrene copolymers and mixtures thereof, and most preferably, ethylene-propylene copolymers, polymethacrylates, hydrogenated isoprene styrene copolymers and mixtures thereof.

The present invention further relates to lubricating oil compositions, wherein the dispersant is derived from an ethylene alpha-olefin backbone functionalized by groups of the formula -CO-Y-R3 wherein Y is O or S, and either R3 is H, hydrocarbyl, substituted hydrocarbyl, aryl, substituted aryl and at least 50 mole % of the functionalized groups are attached to a tertiary carbon atom of the copolymer and derivatized by an amine. Most preferably the amine is "heavy polyamine".

The present invention even further relates to lubricating oil compositions wherein said dispersant is prepared from a polymer functionalized using a reaction selected from the group consisting of halogen assisted, thermal ene, free radical grafting using a catalyst, phenol alkylation and carbonylation via Koch. The invention also relates to concentrates of the dispersant and the viscosity modifier.

The present invention further relates to a lubricating oil composition exhibiting improved low temperature performance comprising an ethylene alpha- olefin dispersant and a viscosity modifier, a basestock and a lubricant oil flow improver, wherein the dispersant has an ethylene content in the range of about 10 to 50 wt. %, more preferably about 30 to 50 wt. %.

The present invention even further relates to the use of solvent extracted, catalytically de-waxed and isomerization dewaxed basestocks.

The preferred LOFI for use in the present invention is selected from the group consisting of an oil-soluble polymer of C10-Cl8 alkyl acrylate or methacrylate and an interpolymer of a vinyl alcohol ester of a C2-C18 alkanoic acid and di(C6-C18 alkyl) fumarate.

Detailed Description of the Preferred Embodiments The low ethylene dispersant of the present invention and the dispersant- viscosity modifier combination of present invention contribute less to the CCS viscosity of a lubricant than conventional additive packages. Although synthetic basestocks produce acceptable CCS performance with relatively low additive levels, these basestocks are more expensive than mineral basestocks. Thus, a formulator would prefer to use more higher viscosity index (VI), i.e., higher neutral number, mineral basestock than lower VI (i.e., lower neutral number) basestock. The viscosity characteristic of a lubricating oil basestock is typically expressed by the neutral number of the oil (e.g., S150N). A higher neutral number at a given temperature indicates a higher viscosity. This neutral number is defined as the viscosity of the basestock at 400C measured in Saybolt Universal Seconds (SUS). Although higher neutral number basestocks (e.g., 150N) have higher CCS viscosities than lower neutral number basestocks (e.g., 100N), they cost less. Use of additives that contribute less to CCS viscosity allows use of higher neutral number basestocks, i.e., higher CCS, less expensive basestocks. Higher neutral number basestocks, in addition to being less expensive, have better volatility and allow for balanced use of refinery basestock streams, since the proportional output of basestock types is essentially fixed.

If conventional mineral basestocks are used in a lubricating oil it is usual to replace, for example, higher viscosity basestocks such as 600N in part by basestocks of 150N or less (or to replace, for example, S150N with S100N) to improve CCS performance in wide multigrade oils. This, however, results in the formulated oil becoming more volatile. Increased oil volatility leads to both increased oil consumption and increased exhaust emissions, both of which are undesirable. The two most significant factors influencing volatility are the solvent neutral number and viscosity index of the basestock. Basestocks with lower viscosity or low viscosity index are rich in more volatile components. Therefore, there is a performance tradeoff in using lower neutral number basestocks to improve CCS.

Thus, it is commercially important to provide a viscosity modifier and dispersant combination with the lowest contribution to CCS viscosity. This permits, for example, less expensive, higher neutral number mineral base oils to be used (without the addition of expensive synthetic basestocks) to produce a lubricant with a viscosity below the CCS maximum viscosity. For example, in a fully formulated oil using Exxon base oils, Exxon Neutral 150 Regular Pour could be substituted partially or completely for Exxon Neutral 100 Low Pour, when using a dispersant and a viscosity modifier according to the present invention.

Lubricating Oil Formulations In the practice of the present invention the preferred dispersant and preferred viscosity modifier are blended with other additives using conventional techniques known to those skilled in the art to make a fully formulated engine crankcase lubricant (e.g., 5W30, 10W30, 15W40, etc.). The dispersants of the present invention may be used by incorporation with other additives to form an "additive package" (i.e., detergent inhibitor package) hereinafter "adpack". The adpack is then typically blended with basestocks and combined with the viscosity modifier for use in blending the final fully formulated lubricant oils.

A. BASESTOCK The basestock used in the lubricating oil may be selected from any of the synthetic or natural oils used as crankcase lubricating oils for spark-ignited and compression-ignited engines. The lubricating oil basestock preferably has a viscosity of about 2.5 to about 12 mm2/s and most preferably about 2.5 to about 9 mm2/s at 100 "C. Mixtures of synthetic and natural mineral base oils may be used if desired.

The lubricant oil formulator must balance the costs and benefits derived from the use of mineral oil basestocks or synthetic basestocks and high or low VI basestocks. For example, a higher VI basestock has a higher viscosity at higher temperatures, has lower volatility, may contribute to lower oil consumption and less engine wear under certain conditions, but has poorer CCS performance, and may have more wax or more difficult wax to treat than a lower VI basestock. A lower VI basestock has lower viscosity at low temperatures and better CCS performance and thus has better oil pumpability, and contributes to lower fuel consumption during engine warm up. As discussed above, the dispersant/viscosity modifier combination of the present invention contributes less than conventional additives to the CCS viscosity of the formulated oil. This allows the oil formulation to increase the content of higher CCS viscosity basestock in the formulation.

The wax or paraffin composition of engine oil is dependent upon the basestocks used in the oil's formulation. The hydrocarbon compositions of lubricant basestocks and the carbon number distribution for each hydrocarbon class (n- paraffins, isoparaffins, cycloparaffins, aromatics) depend upon the crude oil's source and more importantly on the manufacturing technology used. In North America, there are essentially four process pathways used to produce lubricant basestocks: solvent extraction or hydrocracking, followed by solvent dewaxing or catalytic dewaxing.

Each process pathway can produce basestocks with similar physical properties

(viscosity, viscosity index, pour point), but these basestocks may have markedly different paraffin compositions (concentration, carbon number distribution and paraffin type), which impart different low temperature pumpability properties to engine oils formulated with these basestocks. It is believed that basestocks produced by catalytic dewaxing have a broad paraffin carbon number distribution with different types of paraffins that impact interactions with certain dispersants and viscosity modifiers. Such basestocks are preferred for use in the present invention. It is also believed that solvent extracted basestocks are easier to treat for improved low temperature performance. Such basestocks are also preferred herein.

B. DISPERSANTS Ethvlene-Alpha-Olefin Dispersants Polvmer Functionalization The preferred dispersants of the present invention comprise imides or amides prepared from functionalized hydrocarbon polymers (e.g., ethylene alpha-olefin copolymers) reacted (e.g., derivatized) with amines (e.g., heavy polyamine). These preferred dispersants of the present invention are based on the ethylene alpha-olefin polymers as disclosed in USSN 992,192 (incorporated herein by reference). The most preferred ethylene alpha-olefin copolymer is ethylene butene. The preferred ethylene content is about 10 to 50 weight percent, preferably 30 to 50 weight percent. Even more preferred is an ethylene content of about 35 weight percent to about 45 weight percent. Most preferred is about 39 weight percent ethylene content. The ethylene content on a molar basis is preferably about 40 percent to 67 percent. More preferred is 45 to about 60 mole % ethylene.

These polymers can be functionalized using a variety of means including halogen assisted functionalization (e.g., chlorination), the thermal "ene" reaction, free radical grafting using a catalyst (e.g., peroxide) with a carboxylic acid material such as maleic anhydride, and phenol alkylation. These reactions are well known to those skilled in the art. Carbonylation via the Koch reaction is also useful to practice the present invention. The Koch reaction is disclosed in USSN 992,402 (incorporated herein by reference). USSN 992,403 discloses amidation of ethylene alpha-olefin polymers functionalized by the Koch reaction and derivatized with amine and is incorporated by reference herein in its entirety for all purposes. USSN 261,554 discloses ethylene alpha-olefin polymers functionalized by the Koch reaction but derivatized with "heavy polyamine". USSN 261,554 discloses a method for preparing a preferred dispersant for use in the present invention and is incorporated by reference herein in its entirety for all purposes.

The preferred polymers are polymers of ethylene and at least one alpha-olefin having the formula H2C=CHR4 wherein R4 is a straight chain or branched chain alkyl radical comprising 1 to 18 carbon atoms and wherein the polymer contains a high degree of terminal ethenylidene unsaturation. Preferably, R4 in the above formula is an alkyl of from 1 to 8 carbon atoms and more preferably is an alkyl of from 1 to 2 carbon atoms. Therefore, useful comonomers with ethylene in this invention include propylene, 1 -butene, hexene-l, octene-l, etc., and mixtures thereof (e.g., mixtures of propylene and 1 -butene, and the like). Preferred polymers are copolymers of ethylene and propylene and ethylene and butene- 1. Most preferred are copolymers of ethylene and butene- 1.

Preferred ranges of number average molecular weights (Mn) for the copolymer are from about 500 to 20,000, more preferably from about 1,000 to 8,000, even more preferably from about 2,000 to 6,000. Most preferred are average molecular weights of about 2,500. Such polymers generally possess an intrinsic viscosity (as measured in tetralin at 1350C) of between about 0.025 and 0.6 dl/g, preferably between about 0.05 and 0.5 dl/g, most preferably between about 0.075 and 0.4 dl/g. These polymers preferably exhibit a degree of crystallinity such that, when functionalized, they are essentially amorphous.

The preferred ethylene alpha-olefin polymers are further characterized in that up to about 95% and more of the polymer chains possess terminal vinylidene-type unsaturation. Thus, one end of such polymers will preferably be of the formula POLY-C(Rl 1) = CH2 wherein R11 is C1 to C18 alkyl, more preferably C1 to C8 alkyl, and most preferably methyl or ethyl, and wherein POLY represents the polymer chain. A minor amount of the polymer chains can contain terminal ethenyl unsaturation, i.e., POLY-CH=CH2, and a portion of the polymers can contain internal monounsaturation, e.g., POLY-CH=CH(R11), wherein R11 is as defined above.

The preferred ethylene alpha-olefin polymer comprises polymer chains, at least about 30% of which possess terminal vinylidene unsaturation. Preferably at least about 50%, more preferably at least about 60%, and most preferably at least about 75% (e.g., about 75 to about 98%), of such polymer chains exhibit terminal vinylidene unsaturation.

The polymers can be prepared by polymerizing monomer mixtures comprising ethylene with other monomers such as alpha-olefins, preferably from 3 to 4 carbon atoms, in the presence of a metallocene catalyst system comprising at least one metallocene (e.g., a cyclopentadienyl-transition metal compound) and an activator, e.g., alumoxane compound. The comonomer content can be controlled through selection of the metallocene catalyst component and by controlling partial pressure of

the monomers.

The dispersants of the present invention can also be prepared by derivatization, using amines, of polymers functionalized by the Koch reaction, wherein the polymer backbone has Mn 2 about 500, and functionalization is by groups of the formula: -CO-Y-R3 wherein Y is O or S, and either R3 is H, hydrocarbyl and at least about 50 mole % of the functional groups are attached to a tertiary carbon atom of the polymer backbone or R3 is aryl, substituted aryl or substituted hydrocarbyl.

Thus, the functionalized polymer may be depicted by the formula: POLY+CR1 R2}CO-Y-R3)n wherein POLY is a hydrocarbon polymer backbone having a number average molecular weight of at least about 500, n is a number greater than 0 and represents the functionality or average number of functional group per polymer chain. R1, R2 and R3 may be the same or different and are each H, hydrocarbyl with the proviso that either R1 and R2 are selected such that at least about 50 mole % of the -CR1R2 groups wherein both R1 and R2 are not H, or R3 is aryl, substituted aryl or substituted hydrocarbyl.

The Koch reaction permits controlled functionalization of unsaturated polymers. When a carbon of the carbon-carbon double bond is substituted with hydrogen, it will result in an "iso" functional group, i.e., one of R1 or R2 is H; or when a carbon of the double bond is fully substituted with hydrocarbyl groups it will result in a "neo" functional group, i.e., both R1 or R2 are non-hydrogen groups.

Polymers produced by processes which result in terminally unsaturated polymer chain can be functionalized to a relatively high yield in accordance with the Koch reaction. It has been found that the neo acid functionalized polymer can be derivatized to a relatively high yield.

The Koch process also makes use of relatively inexpensive materials, i.e., carbon monoxide at relatively low temperatures and pressures. Also, the leaving group -YR3 can be removed and recycled upon derivatizing the Koch functionalized polymer with amine.

The process for preparing a preferred functionalized polymer of the present invention comprises the steps of catalytically reacting in admixture: (a) at least one hydrocarbon polymer having a number average molecular weight of at least about 500 and an average of at least one ethylenic double bond per

polymer chain; (b) carbon monoxide; (c) at least one acid catalyst; and (d) a nucleophilic trapping agent selected from the group consisting of water, hydroxy-containing compounds and thiol-containing compounds, the reaction being conducted (a) in the absence of reliance on transition metal as a catalyst; or (b) with at least one acid catalyst having a Hammett acidity of less than -7; or (c) wherein functional groups are formed at least about 40 mole % of the ethylenic double bonds; or (d) wherein the nucleophilic trapping agent has a pKa of less than about 12.

The polymers having at least one ethylenic double bond are reacted via a Koch mechanism to form carbonyl or thio carbonyl group-containing compounds, which may subsequently be derivatized. The polymers react with carbon monoxide in the presence of an acid catalyst or a catalyst preferably complexed with the nucleophilic trapping agent. A preferred catalyst is BF3 and preferred catalyst complexes include BF3tH2O and BF3 complexed with 2,4-dichlorophenol. The starting polymer reacts with carbon monoxide at points of unsaturation to form either iso- or neo-acyl groups with the nucleophilic trapping agent, e.g., with water, alcohol (preferably a substituted phenol) or thiol to form respectively a carboxylic acid, carboxylic ester group, or thio ester.

In a preferred process, at least one polymer having at least one carbon-carbon double bond is contacted with an acid catalyst or catalyst complex having a Hammet Scale acidity value of less than -7, preferably from -8.0 to -11.5 and most preferably from -10 to -11.5. Without wishing to be bound by any particular theory, it is believed that a carbenium ion may form at the site of one of carbon-carbon double bonds. The carbenium ion may then react with carbon monoxide to form an acylium cation. The acylium cation may react with at least one nucleophilic trapping agent as defined herein.

At least 40 mole %, preferably at least 50 mole %, more preferably at least 80 mole %, and most preferably 90 mole % of the polymer double bonds will react to form acyl groups wherein the non-carboxyl portion of the acyl group is determined by the identity of the nucleophilic trapping agent, i.e., water forms acid, alcohol forms acid ester and thiol forms thio ester. The polymer functionalized by the recited process of the present invention can be isolated using fluoride salts. The fluoride salt can be selected from the group consisting of ammonium fluoride and sodium fluoride.

Preferred nucleophilic trapping agents are selected from the group consisting of water, monohydric alcohols, polyhydric alcohols hydroxyl-containing aromatic compounds and hetero substituted phenolic compounds. The catalyst and

nucleophilic trapping agent can be added separately or combined to form a catalytic complex.

Following reaction with carbon monoxide (CO), the reaction mixture is further reacted with water or another nucleophilic trapping agent such as an alcohol or phenolic or thiol compound. The use of water releases the catalyst to form an acid.

The use of hydroxy trapping agents releases the catalyst to form an ester; the use of a thiol releases the catalyst to form a thio ester.

Koch product, also referred to herein as functionalized polymer, typically will be derivatized as described hereinafter. Derivatization reactions involving ester functionalized polymer will typically have to displace the alcohol derived moiety therefrom. Consequently, the alcohol derived portion of the Koch functionalized polymer is sometimes referred to herein as a leaving group. The ease with which a leaving group is displaced during derivatization will depend on its acidity, i.e., the higher the acidity the more easily it will be displaced. The acidity, in turn, of the alcohol is expressed in terms of its pKa. The pKa value is determined from the corresponding acidic species in water at room temperature.

Preferred nucleophilic trapping agents include water and hydroxy group containing compounds. Useful hydroxy trapping agents include aliphatic compounds such as monohydric and polyhydric alcohols or aromatic compounds such as phenols and naphthols. The aromatic hydroxy compounds from which the esters of this invention may be derived are illustrated by the following specific examples: phenol, naphthol, cresol, resorcinol, catechol, 2-chlorophenol. Particularly preferred is 2,4- dichlorophenol.

The polymer added to the reactant system can be in a liquid phase. Optionally, the polymer can be dissolved in an inert solvent.

Preferably, the polymer, catalyst, nucleophilic trapping agent and CO are fed to the reactor in a single step. The reactor contents are then held for a desired amount of time under the pressure of the carbon monoxide. The reaction time can range up to 5 hours and typically 0.5 to 4 and more typically from 1 to 2 hours. The reactor contents can then be discharged and the product which is a Koch functionalized polymer comprising either a carboxylic acid or carboxylic ester or thiol ester functional groups separated. Upon discharge, any unreacted CO can be vented off.

Nitrogen can be used to flush the reactor and the vessel to receive the polymer.

Depending on the particular reactants employed, the functionalized polymer containing reaction mixture may be a single phase, a combination of a partitionable polymer and acid phase or an emulsion with either the polymer phase or acid phase being the continuous phase. Upon completion of the reaction, the functionalized

polymer is recovered by suitable means.

Polvmer Derivatization The functionalized polymer, whether prepared by halogenation, "ene" reaction, free radical grafting, phenol alkylation or the Koch reaction, is then derivatized with an amine to make the dispersant. Polyalkylene amines (e.g., polyethylene amines) are preferred for use in the present invention. The most preferred amines are "heavy polyamines." The heavy polyamine as the term is used herein refers to polyamines containing more than six nitrogens per molecule, but preferably polyamine oligomers containing 7 or more nitrogens per molecule and with 2 or more primary amines per molecule. The heavy polyamine comprises more than 28 wt. % (e.g., >32 wt. %) total nitrogen and an equivalent weight of primary amine groups of 120-160 grams per equivalent. Commercial dispersants are based on the reaction of carboxylic acid moieties with a polyamine such as tetraethylenepentamine (TEPA) with five nitrogens per molecule. Commercial TEPA is a distillation cut and contains oligomers with three and four nitrogens as well. Other commercial polyamines known generically as PAM, contain a mixture of ethylene amines where TEPA and pentaethylene hexamine (PEHA) are the major part of the polyamine, usually less than about 80%. Typical PAM is commercially available from suppliers such as the Dow Chemical Company under the trade name E-100 or from the Union Carbide Company as HPA-X. This mixture typically consists of less than 1.0 wt .% low molecular weight amine, 10-15 wt. % TEPA, 40-50 wt. % PEHA and the balance hexaethyleneheptamine (HEHA) and higher oligomers. Typically PAM has 8.7 - 8.9 milliequivalents of primary amine per gram (an equivalent weight of 115 to 112 grams per equivalent of primary amine) and a total nitrogen content of about 33-34 wt. %.

It has been discovered that heavier cuts of PAM oligomers with practically no TEPA and only very small amounts of PEHA but containing primarily oligomers with more than 6 nitrogens and more extensive branching, produce dispersants with improved dispersancy when compared to products derived from regular commercial PAM under similar conditions with the same polymer backbones. An example of one of these heavy polyamine compositions is commercially available from the Dow Chemical Company under the trade name of Polyamine HA-2.

HA-2 is prepared by distilling out the lower boiling polyethylene amine oligomers (light ends) including TEPA. The TEPA content is less than about 1 wt. %.

Only a small amount of PEHA, less than about 25 wt. %, usually about 5 to 15 wt. %, remains in the mixture. The balance is higher nitrogen content oligomers usually with

a greater degree of branching. The heavy polyamine preferably comprises essentially no oxygen.

Derivatization of the Koch reaction functionalized polymer with an amine to form a neoamide is carried out using standard conditions known to those skilled in the art at temperatures of about 150 to 2200C as described in USSN 992403 which is incorporated by reference herein in its entirety for all purposes.

Generally, the amine employed in the reaction mixture is chosen to provide at least an equal number of equivalents of primary amine per equivalent of ester groups in the functionalized copolymer. More particularly, the total amount of amine charged to the mixture typically contains about 1 to 10, preferably about 1 to 6, more preferably about 1.1 to 2.0 and most preferably about 1.1 to 1.5 (e.g., 1.2 to 1.4) equivalents of primary amine per equivalent of ester groups. The excess of primary amine groups is intended to assure substantially complete conversion of the ester groups to amides.

To prepare the Koch reaction dispersant of the invention, the reaction between the functionalized copolymer containing ester groups (i.e., substituted alkyl ester functional groups and/or aryl ester functional groups) and the amine is carried out for a time and under conditions sufficient to form amide groups on the functionalized copolymer with the concomitant release of hydroxy compound.

Amidation or imidation of the functionalized polymer prepared by the other techniques is well known to those skilled in the art. The dispersant can be further post-treated by a variety of conventional post-treatments such as boration, as taught generally in US-A-3087936 and US-A-3254025.

Use The dispersant the present invention will preferably be used in an amount to maintain the combustion by-products dispersed in the lubricant. Since dispersants are typically used in the form of oil solutions (hereinafter concentrates) the amount of additive employed will depend on the concentration of the dispersant polymer in the oil solution comprising the additive. However, by way of illustration, typical concentrates used as dispersants are in an amount of from about 0.5 to 30 weight percent of the blended oil. The amount of dispersant polymer as active ingredient of the blended oil is generally from about 0.1 to 20 weight percent and more preferably from about 1.0 to 8.0 weight percent.

C. VISCOSITY MODIFIERS The viscosity modifiers preferred for practice of this invention are ethylene

alpha-olefin copolymers (e.g., ethylene-propylene, (EP)), hydrogenated diene polymers or hydrogenated diene styrene copolymers (e.g., hydrogenated isoprene styrene, (HIS)) and polyacrylate or polymethacrylate (e.g., polyalkylmethacrylates (PMA)). HIS and EP are preferred. Each of these viscosity modifiers are articles of commerce and are well known in the art. Mixtures of these polymers, either physically or chemically attached, is contemplated within the scope of the invention.

In a preferred embodiment, the present invention discloses a lubricating oil having an ethylene butene copolymer dispersant with an ethylene content of about 10 to 50 weight %, preferably about 30 to 50 weight %, in conjunction with these viscosity modifiers.

Hvdrogenated Diene Polvmer Viscosity Modifiers Linear hydrogenated diene polymers or copolymers with styrene are prepared by anionic copolymerization followed by hydrogenation of the diene (isoprene or butadiene). Number average molecular weights (Mn) of these viscosity modifiers vary between about 50,000 and about 200,000 and molecular weight distributions are narrow. US-A-3965019 and US-A-4032459 describe preparation of polymers of this type and are incorporated by reference herein in their entirety for all purposes.

Hydrogenated isoprene styrene copolymer is preferred. Commercial examples of this type of polymer are ShellvisB 200, 250, 260 and 300, available from Shell International Chemical Company. Multi-arm star-branched hydrogenated poly dienes (e.g., isoprene) divinyl benzene polymers are also known (and are hereinafter referred to as HI-STAR) and are contemplated for use in the present invention. Star-branched polymers are prepared by linking polyisoprene arm anions with divinyl benzene, forming a multi armed star structure and hydrogenating. US-A-4358565 and US-A- 4620048 describe the preparation of polymers of this type and are incorporated by reference herein in their entirety for all purposes. A commercial example of this type of polymer is Shellvis(E) 260 available from Shell International Chemical Company.

Furthermore, Shell ABA block copolymers wherein A is polystyrene and B is a hydrogenated diene such as isoprene are useful in the present invention. Commercial examples of this type of polymer are ShellvisB 40, 50 and 90.

Ethylene Alpha-Olefin Copolymer Viscosity Modifiers Ethylene alpha-olefin copolymers are prepared by copolymerization of ethylene and an alpha-olefin (e.g., propylene) using transition metal base catalysts (e.g., Ziegler-Natta Catalysis). For ethylene propylene copolymers the preferred ethylene content is in the range of about 40 to 80 weight percent. US-A-3697427

discloses mixtures of a higher ethylene, ethylene-propylene copolymer and a lower ethylene, ethylene-propylene copolymer and is incorporated by reference herein, in its entirety for all purposes. Mixtures of other ethylene alpha-olefin copolymers are contemplated for use in the present invention. The ethylene content and distribution in the polymer backbone are critical to solubility in oil and low temperature performance. Number average molecular weights (Mn) range from about 20,000 to 500,000 and in general molecular weight distributions are narrow (e.g., about 1.5 to 7.0). Ethylene propylene diene containing terpolymers (EPDM) can also be used as viscosity modifiers and are contemplated within the scope of the invention. Post polymerization treatment with mechanical mixing and shearing devices such as extruders, masticators, banburys and the like, can be used and depending on the process conditions, such as in the presence or absence of air or peroxide, to reduce the molecular weight and in so doing narrow or broaden the molecular weight distribution, depending on the intended application. PARATONEB 8021 is an example of an ethylene propylene type of viscosity modifier and is commercially available from Exxon Chemical Company.

US-A-4804794 describes narrow molecular weight distribution polymers with a controlled intramolecular compositional distribution and is incorporated by reference herein in its entirety for all purposes. Polymers of this type are contemplated within the scope of the present invention. PARATONE 8451 and PARATONEB 8011 are examples of this type of viscosity modifier and are commercially available from Exxon Chemical Company.

Polvalkylmethacrylate Viscosity Modifier Polyacrylates or polymethacrylates are made by free radical polymerization of alkyl acrylates where the alkyl group could be, for example, butyl, dodecyl, octadecyl, (i.e., C4 to Cos). Hereinafter these polymers are referred to as polyalkylmethacrylates (PMA's). The type of solvent used, temperature and monomer concentration control resultant molecular weight. The long chain polyalkylmethacrylates not only act as viscosity modifiers but alter wax crystallization, so in effect act as flow improvers thus improving low temperature properties. Hydrogenated copolymers of methacrylates and diolefins such as butadiene are also contemplated for use in the present invention. US-A-4533482 describes PMA's and is incorporated by reference herein for all purposes in its entirety. AcryloidB 702 and AcryloidB 956 are examples of this type of viscosity modifier and are commercially available from Rohm and Haas Co.

Multifunctional Viscosity Modifiers Polymers containing polar functional group such as amines act as dispersants for promoting engine sludge suspension. When viscosity modifiers are functionalized and/or derivatized to contain, for example, amine compounds for dispersancy, they are called multifunctional viscosity modifiers (MFVM). Dispersant functionality is introduced by addition of polar functional groups (such as amines) either during copolymerization or by grafting reactions. For polymethacrylates, dispersancy is introduced by incorporation of a small amount of nitrogen-containing monomers such as vinyl pyridine, N-vinyl pyrrolidinone, etc.

Hydrogenated diene-styrene copolymers with dispersant functionality are known and contemplated within the scope of the present invention.

Functionalizing and derivatizing ethylene propylene copolymers is described in US-A-5427702 and US-A-5424367, which are incorporated by reference herein in their entirety and for all purposes. US-A-5427702 and US-A-5424367 disclose a mixture of a functionalized and derivatized higher ethylene, ethylene-propylene copolymer and a functionalized and derivatized lower ethylene, ethylene-propylene copolymer. A MFVM of this type is contemplated for use in the present invention.

PARATONEB 8500 is an example of this type of viscosity modifier and is commercially available from Exxon Chemical Company.

Mixtures of the above viscosity modifier or multifunctional viscosity modifier types, either chemically attached or physically mixed, are contemplated within the scope of the invention.

The viscosity modifier or modifiers used in the present invention will be used in an amount to give the required viscosity characteristics. Since they are typically used in the form of oil solutions the amount of additive employed will depend on the concentration of polymer in the oil solution comprising the additive. However, by way of illustration, typical concentrates of polymer used as VMs are used in amount of from about 1 to about 30% of the blended oil. The amount of VM as active ingredient of the oil is generally from about 0.01 to 6 wt%, and more preferably from about 0.1 to 4 wt%.

D. LUBRICANT OIL FLOW IMPROVERS Lube oil flow improvers, otherwise known as pour point depressants, are added to interfere with wax crystal formation to lower the minimum temperature at which the fluid will flow or can be poured. Thereby smaller, less cohesive wax gel structures and improved flow of the lubricant results. Such additives are well known.

Typical of those additives which improve the low temperature fluidity of the fluid are

C8 to C18 dialkyl fumarate/vinyl acetate copolymers and polyalkylmethacrylates.

Furthermore, use of an appropriate LOFI, as discussed below, prevents or minimizes the interactions between the dispersant, VM and wax and improves low temperature performance.

Polymethacrylate type viscosity modifiers are effective as pour point depressants as well as being viscosity modifiers. LOFI's are generally used in amounts of about 0.01 to 2 weight percent. For poorer basestocks up to 6 weight percent LOFI is used. The preferred range is from about 0.01 to 1.5 weight percent.

Thus, use of an appropriate LOFI will modify the sizes and shapes of the crystallizing waxes. This minimizes the other antagonistic interactions between the dispersant, VM and wax and improves low temperature performance.

Oils with failing MRV and SBV results can sometimes be improved to passing results by substituting a more effective LOFI in the formulation, e.g., one designed for a particular wax composition or by up treating the formulation with additional LOFI.

However, in light of the high cost of LOFI's, it is preferable to use dispersant and viscosity modifiers that contribute less to low temperature performance problems.

A preferred lubricant oil flow improver of the present invention comprises a mixture of (a) at least one low molecular weight polymer of unsaturated carboxy ester represented by the formula: wherein R' is selected from the group consisting of hydrogen and COOR and wherein R is a C14 alkyl group and (b) low molecular weight copolymer of the carboxy ester of formula (I), and vinyl ester represented by the formula: wherein R' comprises an alkyl group containing from 1 to 18 carbon atoms, and (c) at least one low molecular weight non-ethylene containing polymer of interpolymer containing pendent ester groups, having repeating methylene unit derived from a mixture of alcohols present within the structure of said pendent ester groups; the weight ratio of said component (c) to the total weight of (a) + (b) in said composition varying from about 0:0.3 to 1:0.9.

E. OTHER DETERGENT INHIBITOR PACKAGE ADDITIVES Additional additives are typically incorporated into the compositions of the present invention. Examples of such additives are metal or ash-containing detergents, antioxidants, anti-wear agents, friction modifiers, rust inhibitors, anti-foaming agents, demulsifiers.

Metal-containing or ash-forming detergents function both as detergents to reduce or remove deposits and as acid neutralizers or rust inhibitors, thereby reducing wear and corrosion and extending engine life. Detergents generally comprise a polar head with a long hydrophobic tail, with the polar head comprising a metal salt of an acidic organic compound. The salts may contain a substantially stoichiometric amount of the metal in which case they are usually described as normal or neutral salts, and would typically have a total base number or TBN (as may be measured by ASTM D2896) of from 0 to 80. It is possible to include large amounts of a metal base by reacting an excess of a metal compound such as an oxide or hydroxide with an acidic gas such as carbon dioxide. The resulting overbased detergent comprises neutralized detergent as the outer layer of a metal base (e.g., carbonate) micelle. Such overbased detergents may have a TBN of 150 or greater, and typically of from 250 to 450 or more.

Detergents that may be used include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates, and naphthenates and other oil-soluble carboxylates of a metal, particularly the alkali or alkaline earth metals, e.g., sodium, potassium, lithium, calcium, and magnesium. The most commonly used metals are calcium and magnesium, which may both be present in detergents used in a lubricant, and mixtures of calcium and/or magnesium with sodium. Particularly convenient metal detergents are neutral and overbased calcium sulfonates having TBN of from 20 to 450 TBN, and neutral and overbased calcium phenates and sulfurized phenates having TBN of from 50 to 450.

Sulfonates may be prepared from sulfonic acids which are typically obtained by the sulfonation of alkyl substituted aromatic hydrocarbons such as those obtained from the fractionation of petroleum or by the alkylation of aromatic hydrocarbons.

Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl or their halogen derivatives such as chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation may be carried out in the presence of a catalyst with alkylating agents having from about 3 to more than 70 carbon atoms. The alkaryl sulfonates usually contain from about 9 to 80 or more carbon atoms, preferably from about 16 to 60 carbon atoms per alkyl substituted aromatic moiety.

The oil soluble sulfonates or alkaryl sulfonic acids may be neutralized with

oxides, hydroxides, alkoxides, carbonates, carboxylate, sulfides, hydrosulfides, nitrates, borates and ethers of the metal. The amount of metal compound is chosen having regard to the desired TBN of the final product but typically ranges from about 100 to 220 wt % (preferably at least 125 wt %) ofthat stoichiometrically required.

Metal salts of phenols and sulfurized phenols are prepared by reaction with an appropriate metal compound such as an oxide or hydroxide and neutral or overbased products may be obtained by methods well known in the art. Sulfurized phenols may be prepared by reacting a phenol with sulfur or a sulfur containing compound such as hydrogen sulfide, sulfur monohalide or sulfur dihalide, to form products which are generally mixtures of compounds in which 2 or more phenols are bridged by sulfur containing bridges.

Dihydrocarbyl dithiophosphate metal salts are frequently used as anti-wear and antioxidant agents. The metal may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or copper. The zinc salts are most commonly used in lubricating oil in amounts of about 0.1 to 10, preferably about 0.2 to 2 wt. %, based upon the total weight of the lubricating oil composition. They may be prepared in accordance with known techniques by first forming a dihydrocarbyl dithiophosphoric acid (DDPA), usually by reaction of one or more alcohol or a phenol with P2Sg and then neutralizing the formed DDPA with a zinc compound. For example, a dithiophosphoric acid may be made by reacting mixtures of primary and secondary alcohols. Alternatively, multiple dithiophosphoric acids can be prepared where the hydrocarbyl groups on one are entirely secondary in character and the hydrocarbyl groups on the others are entirely primary in character. To make the zinc salt any basic or neutral zinc compound could be used but the oxides, hydroxides and carbonates are most generally employed. Commercial additives frequently contain an excess of zinc due to use of an excess of the basic zinc compound in the neutralization reaction.

The preferred zinc dihydrocarbyl dithiophosphates are oil soluble salts of dihydrocarbyl dithiophosphoric acids and may be represented by the following formula: wherein R and R' may be the same or different hydrocarbyl radicals containing from 1 to 18, preferably 2 to 12, carbon atoms and including radicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R and R' groups are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals may, for example,

be ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl. In order to obtain oil solubility, the total number of carbon atoms (i.e., R and R') in the dithiophosphoric acid will generally be about 5 or greater. The zinc dihydrocarbyl dithiophosphate can therefore comprise zinc dialkyl dithiophosphates. Conveniently at least 50 (mole) % of the alcohols used to introduce hydrocarbyl groups into the dithiophosphoric acids are secondary alcohols.

Oxidation inhibitors or antioxidants reduce the tendency of mineral oils to deteriorate in service, which deterioration can be evidenced by the products of oxidation such as sludge and varnish-like deposits on the metal surfaces and by viscosity growth. Such oxidation inhibitors include hindered phenols, alkaline earth metal salts of alkylphenolthioesters having preferably Cs to C12 alkyl side chains, calcium nonylphenol sulfide, ashless oil soluble phenates and sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons, phosphorous esters, metal thiocarbamates, oil soluble copper compounds as described in US-A-4867890, and molybdenum containing compounds.

Typical oil soluble aromatic amines having at least two aromatic groups attached directly to one amine nitrogen contain from 6 to 16 carbon atoms. The amines may contain more than two aromatic groups. Compounds having a total of at least three aromatic groups in which two aromatic groups are linked by a covalent bond or by an atom or group (e.g., an oxygen or sulfur atom, or a -CO-, -S 02- or alkylene group) and two are directly attached to one amine nitrogen also considered aromatic amines. The aromatic rings are typically substituted by one or more substituents selected from alkyl, cycloalkyl, alkoxy, aryloxy, acyl, acylamino, hydroxy, and nitro groups.

Friction modifiers may be included to improve fuel economy. Oil-soluble alkoxylated mono- and diamines are well known to improve boundary layer lubrication. The amines may be used as such or in the form of an adduct or reaction product with a boron compound such as a boric oxide, boron halide, metaborate, boric acid or a mono-, di- or trialkyl borate.

Other friction modifiers are known. Among these are esters formed by reacting carboxylic acids and anhydrides with alkanols. Other conventional friction modifiers generally consist of a polar terminal group (e.g., carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. Esters of carboxylic acids and anhydrides with alkanols are described in US-A-4702850. Examples of other conventional friction modifiers are described by M. Belzer in the "Journal of

Tribology" (1992), Vol. 114, pp. 675-682 and M. Belzer and S. Jahanmir in "Lubrication Science" (1988), Vol. 1, pp. 3-26.

Rust inhibitors selected from the group consisting of nonionic polyoxyalkylene polyols and esters thereof, polyoxyalkylene phenols, and anionic alkyl sulfonic acids may be used.

Copper and lead bearing corrosion inhibitors may be used, but are typically not required with the formulation of the present invention. Typically such compounds are the thiadiazole polysulfides containing from 5 to 50 carbon atoms, their derivatives and polymers thereof. Derivatives of 1,3,4 thiadiazoles such as those described in US-A-2719125; US-A-2719126; and US-A-3087932; are typical. Other similar materials 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 4,193,882. Other additives are the thio and polythio sulfenamides of thiadiazoles such as those described in GB-A-1560830.

Benzotriazoles derivatives also fall within this class of additives. When these compounds are included in the lubricating composition, they are preferably present in an amount not exceeding about 0.2 wt % active ingredient.

A small amount of a demulsifying component may be used. A preferred demulsifying component is described in EP-A-330522. It is obtained by reacting an alkylene oxide with an adduct obtained by reacting a bis-epoxide with a polyhydric alcohol. The demulsifier should be used at a level not exceeding about 0.1 mass % active ingredient. A treat rate of about 0.001 to 0.05 mass % active ingredient is convenient.

Foam control can be provided by many compounds including an antifoamant of the polysiloxane type, for example, silicone oil or polydimethyl siloxane.

Some of the above-mentioned additives can provide a multiplicity of effects; thus for example, a single additive may act as a dispersant-oxidation inhibitor. This approach is well known and does not require further elaboration.

When lubricating compositions contain one or more of the above-mentioned additives, each additive is typically blended into the base oil in an amount which enables the additive to provide its desired function. Representative approximate effective amounts of such additives, when used in crankcase lubricants, are listed below. All the values listed are stated as approximate mass percent active ingredient.

ADDITIVE MASS °/O MASS % (Broad) (Preferred) Dispersant 0.1-20 1-8 Metal detergents 0.1-15 0.2-9 Corrosion Inhibitor 0 - 5 0 - 1.5 Metal dihydrocarbyl dithiophosphate 0.1 - 6 0.1-4 Supplemental anti-oxidant 0 -5 0.01 - 1.5 Pour Point Depressant 0.01 - 5 0.01- 1.5 Anti-Foaming Agent 0 - 5 0.001-0.15 Supplemental Anti-wear Agents O - 0.5 0-0.2 Friction Modifier 0- 5 0 - 1.5 Viscosity Modifier 0.01-6 0.1 - 4 Mineral or Synthetic Base Oil Balance Balance

The components may be incorporated into a base oil in any convenient way.

Thus, each of the components can be added directly to the oil by dispersing or dissolving it in the oil at the desired level of concentration. Such blending may occur at ambient temperature or at an elevated temperature.

Preferably all the additives except for the viscosity modifier and the flow improver are blended into a concentrate or additive package described herein as the detergent inhibitor package, that is subsequently blended into basestock and combined with the viscosity modifier and flow improver to make finished lubricant. Use of such concentrates is conventional. The concentrate will typically be formulated to contain the additive(s) in proper amounts to provide the desired concentration in the final formulation when the concentrate is combined with a predetermined amount of basestock.

Preferably the concentrate is made in accordance with the method described in US-A-4938880. That patent describes making a premix of a dispersant and metal detergents that is pre-blended at a temperature of at least about 100°C. Thereafter, the pre-mix is cooled to at least 850C and the additional components are added.

The final formulations may employ from 2 to 15 mass % and preferably 5 to 10 mass %, typically about 7 to 8 mass % of the concentrate or additive package with the remainder being base oil.

The present invention will be further understood by the following examples which include preferred embodiments. In the following examples, number average molecular weight (Mn) of the polymers was determined by Gel Permeation Chromatography (GPC) and the ethylene content of the polymers were determined by carbon 13 NMR. The nitrogen content of the dispersants was measured by the Carlo

Urba apparatus. The boron content of the dispersants was measured by Inductively Coupled Plasma Emission Spectoscopy (ICPES).

All weight percents expressed herein (unless otherwise indicated) are based on approximate active ingredient (AI) content of the additive, and/or upon the total weight of any additive package, or formulation which will be the sum of the AI weight of each additive plus the weight of total oil or diluent.

Examples In the following examples experimental SAE 5W30 SH lubricating oils were prepared using Exxon USA, Shell Wood River and Mobil Paulsboro basestocks, via conventional blending techniques known to one skilled in the art.

Additive packages (Adpacks) containing conventional additives but including the following dispersants were used. Adpack "A" contains a low (39 weight percent) ethylene, ethylene-butene dispersant, which is representative of the present invention.

Adpack "B" contains a high (51 weight percent) ethylene, ethylene-butene dispersant and Adpack "C" contains a commercial polyisobutylene based dispersant.

The above Adpacks were blended with commercial viscosity modifiers; ethylene-propylene, copolymers (PARATONEB 8451 and PARATONEO 8021) polymethacrylates polymers (AcrylicB 956 and AcryloidB 702), hydrogenated isoprene styrene (ShellvisX 90) and hydrogenated isoprene divinyl benzene star polymers (ShellvisB 260).

In addition, commercial dialkyl fumarate vinyl acetate lubricant oil flow improvers (LOFI), PARAFLOWB 387 and PARAFLOWB 390 available from Exxon Chemical Company were used.

Examples 1-4 (CCS) The blended oils were tested for dynamic viscosity at -250C using the cold cranking simulator (CCS) substantially in accordance with test method ASTM D- 5293 which is incorporated by reference herein for all purposes. The results are reported in centipoise (cps). For a 5W30 oil, 3500 cps is considered a passing value, with lower numbers being better. Lubricant oil formulators prefer values around 3200. Lower CCS values allow formulators more flexibility in the type of basestock that can be used in the formulations. A 100 cps difference between results would be considered significant.

Example 1-A An ethylene-butene copolymer (39.2 wt. % ethylene, Mn = 2500) prepared via Ziegler-Natta polymerization with zirconium metallocene catalyst and methyl alumoxane cocatalyst according to known procedures was carbonylated with carbon monoxide in the presence of BF3 and 2,4-dichlorophenol in a continuous stirred tank reactor at 500C. The resulting ester (functionalized copolymer) was derivatized (e.g., aminated) with "heavy polyamine." Using known procedures 2906 gms of the functionalized copolymer were reacted using 180.2 gms of heavy polyamine from Dow Chemical Company identified as HA-2 PAM (32.8 wt. % total nitrogen). 2105 gms of base oil were added and the product borated using known procedures. The resulting product analyzed for about 1.2% nitrogen and about 0.23% boron. The product was then diluted with base oil to 40 wt. % active ingredient.

The resulting dispersant (A) was blended 25.803 mass % with conventional adpack ingredients including a detergent, zinc, AO's and a demulsifier using procedures known to one skilled in the art to make Adpack "A".

Example 1-B An ethylene-butene copolymer (51.0 wt. % ethylene, Mn = 5200) prepared via Ziegler-Natta polymerization with zirconium metallocene catalyst and methyl alumoxane cocatalyst according to known procedures was carbonylated with carbon monoxide in the presence of BF3 and 2,4-dichlorophenol in a continuous stirred tank reactor at 500C. The resulting ester was aminated substantially in accordance with the procedures of Example 1-A. The nitrogen and boron content of the product was about the same as the product in Example 1-A. The product was then diluted with base oil to 40 wt. % active ingredient. The resulting dispersant (B) was blended 25.803 mass percent with conventional adpack ingredients including a detergent, zinc, AO's and a demulsifier using procedures known to one skilled in the art to make Adpack "B".

Example 2 PARABARX 9260, a commercially available dispersant (C) from Exxon Chemical Company based on polyisobutylene and commercial PAM, was blended 51.584 mass percent with conventional adpack ingredients including a detergent, zinc, AO's and a demulsifier using procedures known to one skilled in the art to make Adpack "C".

Using procedures known to those skilled in the art the above Adpacks were blended with the above viscosity modifiers and basestocks as typically used to prepare experimental SAE 5W30 SH formulations. The blends were tested for kinematic

viscosity at 1000C and CCS at -250C.

It can be seen from the results reported in the tables that the CCS values for the formulation containing the "low" ethylene, ethylene-butene dispersant (39 weight percent) performs better, i.e., has lower CCS results in cps, than the formulation containing the "high" ethylene, ethylene-butene dispersant (51 weight percent) and better than the formulation containing the commercial polyisobutylene based dispersant, in a given basestock, in combination with a given viscosity modifier.

Table 1 shows formulations using Exxon basestocks. Except for the formulation containing the Acryloid 956 viscosity modifier, all formulations containing the low ethylene dispersant had significantly lower CCS values than the formulations using either the high ethylene dispersant or the polyisobutylene based dispersant. Since the low ethylene dispersant containing formulations were also significantly below the CCS target, for a given viscosity modifier, a lubricant oil formulator could have reduced the amount of the lower CCS Exxon 100 NLP basestock and replaced it with higher CCS Exxon 150 NRP basestock and still be below the CCS target. Thus the formulator could realize the cost and performance (better volatility etc.) benefits derived from the use of the higher VI (higher neutral number) basestock described earlier.

Table 2 shows formulations use the Shell Wood River basestock. In all cases the formulations containing low ethylene dispersant had better CCS than the formulations containing either the high ethylene or polyisobutylene dispersant.

Several of the formulations were above the maximum CCS target (3500 cps). In order to use the formulations containing those particular viscosity modifiers, some portion of lower CCS, but costlier, synthetic basestock would be needed in place of Shell HVI 100N in order to pass CCS. However, if using the low ethylene dispersant, less of the costly synthetic basestock would be needed than when using either the high ethylene or polyisobutylene based dispersant, in order to pass CCS.

Table 3 shows formulations using Mobil Paulsboro basestocks. Except for the formulations containing the Acryloid 956 viscosity modifier, all formulations containing the low ethylene dispersant had significantly lower CCS values than formulations containing either the high ethylene or polyisobutylene based dispersant.

Since the low ethylene dispersant containing formulations were also significantly below the CCS target for a given viscosity modifier, a formulator could have replaced a portion of the Mobil MTB 511 basestock with a less expensive, higher VI (higher neutral number) basestock and still be below the maximum CCS value.

Table 1 Experimental SAE 5W30 SH Formulations using Exxon USA basestocks Basestock Adpack Viscosity Viscosity Exx 100 Exx 150 A B C LOFI(I) LOFI(2) KV CCS Modifier Modifier NLP NRP 100"C, -25°C, Type Amount cSt(3) cps(4) Weight % 7.4 62.8 7 22.4 0.4 10.39 - 3030 PARATONE 4.5 65.7 7 22.4 0.4 10.54 3400 8451(5) 8.0 73.4 7 11.2 0.4 10.28 3210 Weight % 7.4 62.8 7 22.4 0.4 10.64 3300 PARATONE 3.4 66.8 7 22.4 0.4 10.45 3510 8021 (5) 7.7 73.7 7 11.2 0.4 10.34 3670 Weight % 5.0 65.6 7 22.4 10.25 3750 Acryloid 2.9 67.7 7 22.4 10.78 3750 956 (6) 5.5 76.3 7 11.2 10.32 3760 Weight % 4.3 66.3 7 22.4 10.32 3260 Acryloid 2.1 68.5 7 22.4 10.48 3530 702 (6) 4.7 77.1 7 11.2 10.37 3560 Weight % 6.5 63.7 7 22.4 0.4 10.55 3050 Shell Vis 3.3 66.9 7 22.4 0.4 10.69 3350 90(7) 7.0 74.4 7 11.2 0.4 10.26 3350 Weight % 6.0 64.2 7 22.4 0.4 10.43 3010 Shell vies 2.8 67.4 7 22.4 0.4 10.61 3310 260 (8) 6.7 74.7 7 11.2 0.4 10.38 3110 (1) Lube Oil Flow Improver (LOFI) PARAFLOW 387 commercially available from Exxon Chemical Co.

(2) LOFI PARAFLOW 390 commercially available from Exxon Chemical Co.

(3) Kinematic Viscosity in Centistokes (Target 9.3 to 12.5 at 1000C) (4) Dynamic Viscosity in centipoise as measured in Cold Cranking Simulator at -25°C. (ASTM D- 5293) (Target <3500 cps) (5) EP (6) PMA (no LOFI used because PMA's also act as LOFI) (7) HIS (8) Hl-Star Table 2 Experimental SAE 5W30 SH Formulations using Shell Wood River basestocks Basestock Adpack Viscosity Viscosity SWR HVI A B C LOFI(I) LOFI(2) KV CCS Modifier Modifier 100N 100°C, -25°C, Type Amount cSt cps Weight % 7.7 69.5 22.4 0.4 10.63 3120 PARATONE 4.1 73.1 22.4 0.4 10.71 4050 8451 8.4 80.0 11.2 0.4 10.57 3230 Weight % 7.3 69.9 22.4 0.4 10.59 3680 PARATONE 4.1 73.1 22.4 0.4 10.75 4240 8021 7.0 81.4 11.2 0.4 10.56 4280 Weight % 5.5 72.1 22.4 10.50 4420 Acryloid 2.6 75.0 22.4 10.41 4750 956 6.2 82.6 11.2 10.45 4720 Weight% 4.5 73.1 22.4 10.51 3940 Acryloid 2.0 75.6 22.4 10.35 4350 702 4.8 84.0 11.2 10.30 4130 Weight % 6.2 71.0 22.4 0.4 10.59 3780 Shell Vis 3.1 74.1 22.4 0.4 10.52 4280 90 7.2 81.2 11.2 0.4 10.23 4310 Weight % 6.1 71.1 22.4 0.4 10.23 3480 Shell Vis 2.7 74.5 22.4 0.4 10.41 4200 260 6.8 81.6 11.2 0.4 10.25 3810

Table 3 Experimental SAE 5W30 SH Formulations using Mobil Paulsboro basestocks Basestock Adpack Viscosity Viscosity Mobil A B C LOFI(1) LOFI(2) KV CCS Modifier Modifier MTB 511 100"C, -250C, Type Amount cSt cps Weight % 7.6 69.6 22.4 0.4 10.56 3090 PARATONE 3.6 73.6 22.4 0.4 10.64 3400 8451 8.2 80.2 11.2 0.4 10.49 3400 Weight % 7.3 69.9 22.4 0.4 10.59 3245 PARATONE 3.0 74.2 22.4 0.4 10.37 3480 8021 8.2 80.2 11.2 0.4 10.77 3620 Weight % 5.1 72.5 22.4 10.23 3710 Acryloid 2.7 74.9 22.4 10.71 3700 956 5.7 83.1 11.2 10.60 4130 Weight % 4.5 73.1 22.4 10.51 3390 Acryloid 2.0 75.6 22.4 10.52 3530 702 4.8 84.0 11.2 10.68 3680 Weight % 6.5 70.7 22.4 0.4 10.47 3230 Shell Vis 3.2 74.0 22.4 0.4 10.70 3470 90 7.1 81.3 11.2 0.4 10.44 3650 Weight % 6.1 71.1 22.4 0.4 10.28 3060 Shell Vis 3.1 74.1 22.4 0.4 10.65 3480 260 6.7 81.7 11.2 0.4 10.47 3360 In the following examples a lower ethylene content, ethylene-butene dispersant than example I-A and a higher ethylene content, ethylene-butene dispersant than example I-B were used.

Example 3 In this example experimental 5W30 SH formulations were prepared using Exxon USA basestocks, PARATONE 8451 viscosity modifier and an adpack containing either 35 weight percent ethylene, ethylene-butene dispersant, which is representative of the present invention, 65 weight percent ethylene, ethylene-butene dispersant or a polyisobutylene based dispersant. The procedures used were substantially the same as used in Examples 1 and 2 above. The results showed that the formulation using the low ethylene dispersant had the best (lowest) CCS at 2790 cps, while the formulations using the high ethylene and polyisobutylene dispersant were about the same at 3160 and 3120 cps.

Example 4 In this example experimental 5W30 SH formulations were prepared using Exxon USA basestocks, PARATONE 8021 viscosity modifier and an adpack containing either 35 weight percent ethylene, ethylene-butene dispersant which is representative of the present invention, 65 weight percent ethylene, ethylene-butene dispersant or a polyisobutylene based dispersant. The procedures used were substantially the same as used in Examples 1 and 2 above. The results showed that the formulations using the low ethylene dispersant had the best (lowest) CCS at 2950 cps, while the formulations using the polyisobutylene and high ethylene dispersant were about the same at 3220 and 3260 cps.

Thus an oil formulator, using the above commercial viscosity modifiers and a 35 weight percent ethylene, ethylene-butene dispersant could increase the amount of higher CCS basestock in the formulation, still be below the CCS target and obtain the cost and other advantages with use of a higher CCS basestock.

Examples 5-8 (MRV and Scanning Brookfield) Example 5 Using procedures known to those skilled in the art, the above Adpacks were blended with the above viscosity modifiers and the above basestocks to prepare experimental SAE 5-W-30 SH formulations. The blends were tested for kinematic viscosity at 1000C to confirm meeting the target of 9.3 to 12.5 centistokes (cSt). The blends were then tested using the MRV-TP-1, Pour Point and Scanning Brookfield.

In the MRV test, for a 5W30 oil, the viscosity is measured in cps at -300C.

Results above 30,000 cps are considered failures. Results reported as "solid" are too viscous to measure and are hence failures. Lower values in cps are better. A 3000- 4000 cps difference in values is considered significant. The MRV yield stress is essentially a pass or fail test. In order to pass, the yield stress must be less than 35 Pa.

The Pour Point of the 5W30 formulation must be less than -35°C, with more negative values (i.e., colder) being better.

The Scanning Brookfield is similar to MRV. For a 5W30 oil, Scanning Brookfield viscosities above 30,000 cps at -300C are considered failures. Another part of the Scanning Brookfield test is the temperature at which the viscosity is 30,000 cps. Passes must be less than or equal to -300C. The Scanning Brookfield Gelation Index, which is similar to yield stress in the MRV, is also reported. Values above 16 are failures. Kinematic viscosity, CCS and MRV-TP-1 are part of the SAE J300

lubricant specification. Pour point and SBV are not part of the specification, but lubricant formulators expect oils to pass these tests.

Table 4 shows results of formulations using Exxon USA basestocks. Except for two failing results, all MRV viscosities were well below the 30,000 maximum.

The failures, 61,365 cps and solid (too viscous to measure) occurred with the high ethylene, ethylene-butene dispersant and the PMA viscosity modifiers. These formulations also failed the MRV yield stress (>175Pa and solid). These formulations also failed Pour Point. In the Scanning Brookfield, failures occurred with a high ethylene, ethylene-butene dispersant in combination with one of the EP viscosity modifiers. Several of the dispersant/PMA combinations also failed. These data show that in the Exxon basestocks, the EP and H1S/HI-Star viscosity modifiers perform about the same when used with either the low ethylene, ethylene-butene dispersant or the polyisobutylene dispersant. The high ethylene, ethylene-butene dispersant performed slightly poorer. The PMA viscosity modifier performed poorer, but use of a LOFI may have improved its performance.

It is believed that the wax content of the Exxon basestock is less harsh to low temperature performance, thus varying dispersant type and/or ethylene content does not impact low temperature performance as dramatically as with other basestocks.

Table 5 shows results of formulations using Shell Wood River basestocks. In MRV viscosity, all three failures occurred with the high ethylene, ethylene-butene dispersant. In MRV yield stress, Pour Point and Scanning Brookfield, failures occurred with the high-ethylene, ethylene-butene dispersant and the PMA's with either of the dispersants. It appears that the HIS/HI-Star viscosity modifiers pass these low temperature tests with any of the dispersants. The EP viscosity modifiers perform better with the polyisobutylene dispersant or low ethylene, ethylene-butene dispersant.

The PMA viscosity modifier again performed poorer in this basestock without the use of LOFI.

Table 6 shows results of formulations using Mobil Paulsboro basestocks. In MRV viscosity, the failures again occurred with the high ethylene, ethylene-butene dispersant. In MRV yield stress, Pour Point and Scanning Brookfield, the failures again occurred with the high ethylene, ethylene-butene dispersant and the PMA.

Again it appears that the HIS/HI-Star viscosity modifiers performs well with any of the dispersants. The EP viscosity modifiers perform better with the polyisobutylene dispersants or the low ethylene, ethylene-butene dispersant. The PMA viscosity modifier again performed poorer in this basestock without the use of LOFI. As can be seen in the data, in a given basestock, the MRV, Pour Point and Scanning Brookfield

performance with the low ethylene, ethylene-butene dispersant varies depending on the viscosity modifier used.

It appears that in a wide array of basestock types, the HIS/HI-Star viscosity modifiers perform better than ethylene propylene viscosity modifiers, which perform better than PMA viscosity modifiers. Further, better MRV, Pour Point and Scanning Brookfield results occur with the low ethylene, ethylene-butene dispersant than the high ethylene, ethylene-butene dispersant. Should a lubricant oil formulator wish to obtain the CCS improvement obtainable through use of a ethylene-butene dispersant over a polyisobutylene dispersant, based on the data in the tables, in general, the formulator would select a low ethylene, ethylene-butene dispersant rather than a high ethylene, ethylene-butene dispersant.

Table 4<BR> Experimental SAE 5W30 SH Formulations Using Exxon USA Basestocks<BR> Basestock Adpack MRV-TP-1 Scanning Brookf d<BR> Viscosity Viscosity Exx 100 Exx 150 A B C LOFI(1) LOFI(2) Viscosity Yield Pour Point Viscosity Temp @ Gel Index<BR> Modifier Modifier NLP NRP -30°C Stress °C -30°C 30,000 cps 16 Max.<BR> <P>Type Amount 30,000 cps <35 Pa #-35 Max. 30,000 cps #-30°C<BR> Max. Max.<BR> <P>Weight % 7.4 62.8 7 22.4 0.4 18250 <35 -30 20300 -31.6 8.2<BR> PARATONE 4.5 65.7 7 22.4 0.4 15310 <35 -33 38200 -29.6 14.7<BR> 8451 (3) 8.0 73.4 7 11.2 0.4 12270 <35 -33 14300 -33.8 5.4<BR> Weight % 7.4 62.8 7 22.4 0.4 15650 <35 -33 14300 -33.9 6.3<BR> PARATONE 3.4 66.8 7 22.4 0.4 17160 <35 -33 15800 -33 6.7<BR> 8021 (3) 7.7 73.7 7 11.2 0.4 12800 <35 < -36 11800 -35 6.5<BR> Weight % 5.0 65.6 7 22.4 10170 <35 < -36 Fail -27.8 13.3<BR> Acryloid 2.9 67.7 7 22.4 61365 >175 -21 Fail -21.5 24.1<BR> 956 (4) 5.5 76.3 7 11.2 9540 <35 < -36 Fail -24.5 12.9<BR> Weight % 4.3 66.3 7 22.4 9520 <35 < -36 Fail -27.7 13.3<BR> Acryloid 2.1 68.5 7 22.4 solid solid -18 Fail -18.7 39.8<BR> 702 (4) 4.7 77.1 7 11.2 8700 <35 < -36 28100 -30.6 11.8<BR> Weight % 6.5 63.7 7 22.4 0.4 18230 <35 -33 16400 -33.5 5.6<BR> Shell Vis 3.3 66.9 7 22.4 0.4 17710 <35 < -36 17700 -32.4 9.5<BR> 90 (5) 7.0 74.4 7 11.2 0.4 14990 <35 < -36 16200 -33.8 5.1<BR> Weight % 6.0 64.2 7 22.4 0.4 16140 <35 < -36 16300 -33.6 5<BR> Shell Vis 2.8 67.4 7 22.4 0.4 17730 <35 < -36 17400 -32.4 10.7<BR> 260 (6) 6.7 74.7 7 11.2 0.4 13990 <35 < -36 17600 -33.1 5.5<BR> (1) Lube Oil Flow Improver (LOFI) PARAFLOW 387 commercially available from Exxon Chemical Co.<BR> <P>(2) LOFI PARAFLOW 390 commercially available from Exxon Chemical Co.<BR> <P>(3) EP<BR> (4) PMA (no LOFI used because PMA's also act as LOFI)<BR> (5) HIS<BR> (6) HI - Star TABLE 5<BR> Experimental SAE 5W30 SH Formulations Using Shell Wood River Basestocks<BR> Basestock Adpack MRV-TP-1 Scanning Brookfield<BR> Viscosity Viscosity SWR HVI A B C LOFI(1) LOFI(2) Viscosity Yield Pour Point Viscosity Temp @ Gel<BR> Modifier Modifier 100N -30°C Stress @@ -30°C 30,000 cps Index<BR> Type Amount 30,000 cps <35 Pa #-35 Max. 30,000 cps #-30°C 16 Max.<BR> <P>Max. Max.<BR> <P>Weight % 7.7 69.5 22.4 0.4 13760 <35 -30 12900 -32.7 5.8<BR> PARATONE 4.1 73.1 22.4 0.4 19390 <35 -30 27600 -30.3 6.7<BR> 8451 8.4 80.0 11.2 0.4 10610 <35 -33 14900 -33.9 5.3<BR> Weight 7.3 69.9 22.4 0.4 16990 <35 -30 18300 -32.7 5.1<BR> PARATONE 4.1 73.1 22.4 0.4 solid solid -30 24200 -31.1 5.8<BR> 8021 7.0 81.4 11.2 0.4 18470 <35 < -36 24300 -31.4 6<BR> Weight % 5.5 72.1 22.4 16640 <35 -27 35400 -29.4 8.1<BR> Acryloid 2.6 75.0 22.4 solid solid -9 Fail -13.4 57.14<BR> 956 6.2 82.6 11.2 11660 <35 -30 18900 -31.6 7.2<BR> Weight % 4.5 73.1 22.4 63400 solid -15 Fail -18.2 44.7<BR> Acryloid 2.0 75.6 22.4 soid soid -9 Fail -12.1 53.5<BR> 702 4.8 84.0 11.2 10280 <35 -24 23000 -31.4 4.7<BR> Weight % 6.2 71.0 22.4 0.4 19570 <35 -33 21100 -32 5.4<BR> Shell Vis 3.1 74.1 22.4 0.4 18250 <35 < -36 20300 -32.4 5.5<BR> 90 7.2 81.2 11.2 0.4 17820 <35 < -36 18300 -33.1 4.3<BR> Weight % 6.1 71.1 22.4 0.4 16510 <35 -33 19000 -32.6 4.4<BR> Shell Vis 2.7 74.5 22.4 0.4 17590 <35 < -36 19900 -32.4 4.9<BR> 260 6.8 81.6 11.2 0.4 16610 <35 < -36 21000 -32.1 7.2 Table 6<BR> Experimental SAE 5W30 SH Formulations Using Mobil Paulsboro Basestocks<BR> Basestock Adpack MRV-TP-1 Scanning Brookfield<BR> Viscosity Viscosity Mobil A B C LOFI(1) LOFI(2) Viscosity Yield Pour Point Viscosity Temp @ Gel<BR> Modifier Modifier MTB 511 -30°C Stress °C -30°C 30,000 cps Index<BR> Type Amount 30,000 cps <35 Pa #-35 Max. 30,000 cps #-30 Max. 16 Max.<BR> <P>Max. Max.<BR> <P>Weigt 7.6 69.6 22.4 0.4 9730 <35 -33 10800 -35.3 5.8<BR> PARATONE 3.6 73.6 22.4 0.4 11860 <35 -30 15800 -31.4 11.3<BR> 8451 8.2 80.2 11.2 0.4 10210 <35 -33 11400 -35.5 4.7<BR> Weight % 7.3 69.9 22.4 0.4 13210 <35 -33 14600 -34.4 4.7<BR> PARATONE 3.0 74.2 22.4 0.4 113490 >70 -33 14600 -34.7 6.5<BR> 8021 8.2 80.2 11.2 0.4 19710 <35 < -36 16500 -34.1 5.2<BR> Weight % 5.1 72.5 22.4 12050 <35 < -36 19400 -31.7 7.2<BR> Acryloid 2.7 74.9 22.4 39200 <140 -12 Fail -14.2 31.2<BR> 956 5.7 83.1 11.2 10192 <35 < -36 20200 -31.4 7.9<BR> Weight 4.5 73.1 22.4 29060 <105 -33 Fail -21.5 20.1<BR> Acryloid 2.0 75.6 22.4 soid solid -15 Fail -13.6 37.3<BR> 702 4.8 84.0 11.2 15350 <35 -27 39300 -28.2 18.4<BR> Weight % 6.5 70.7 22.4 0.4 16080 <35 < -36 16200 -33.9 4.3<BR> Shell Vis 3.2 74.0 22.4 0.4 11800 <35 < -36 14600 -34.9 4.1<BR> 90 7.1 81.3 11.2 0.4 13440 <35 < -36 17900 -33.3 4.2<BR> Weight % 6.1 71.1 22.4 0.4 11160 <35 < -36 16100 -34 4.2<BR> Shell Vis 3.1 74.1 22.4 0.4 11020 <35 < -36 15400 -34.5 4.3<BR> 260 6.7 81.7 11.2 0.4 13010 <35 < -36 16800 -33.8 4.1 In the following examples, a lower ethylene content, ethylene-butene dispersant than Example I-A and a higher ethylene content, ethylene-butene dispersant than Example I-B was used.

Example 6 In this example experimental 5W30 SH formulations were prepared using Exxon USA basestocks, PARATONE 8451 viscosity modifier and an adpack containing either 35 weight percent ethylene, ethylene-butene dispersant (A), which is representative of the present invention, 65 weight percent ethylene, ethylene- butene dispersant (B) or polyisobutylene based dispersant (C). The procedures used were substantially the same as used in Examples 1 and 2 above.

The table below shows the formulations' low temperature performance.

(A) (B) (C) MRV-TP- 1 Viscosity -30°C cps 12,300 Solid 10,510 Yield Stress Pa <35 Solid <35 Pour Point "C -33 -18 -36 Scanning Brookfield Viscosity -30°C cps 15,700 Fail 12,100 Temperature @ 30,000 cps -32.7 -18.4 -35 Gel Index 6.1 42 4.7 The results showed that the formulation containing the polyisobutylene based dispersant had slightly better MRV-TP-1 (lower viscosity) and Pour Point (lower temperature) than the low ethylene, ethylene-butene dispersant. However, the results also showed that the low ethylene, ethylene-butene dispersant was superior to the high ethylene, ethylene-butene dispersant, which failed both tests.

Example 7 In this example experimental 5W30 SH formulations were prepared using Exxon USA basestocks, PARATONE 8021 viscosity modifier and an adpack containing either 35 weight percent ethylene, ethylene-butene dispersant (A), 65 weight percent ethylene, ethylene-butene dispersant (B) or polyisobutylene based dispersant (C). The procedures used were substantially the same as used in Examples 1 and 2 above.

The table below shows the formulations' low temperature performance.

(A) (B) (C) MRV-TP-1 Viscosity -30°C cps 13,850 Solid 12,200 Yield Stress Pa <35 Solid <35 Pour Point "C -33 -18 -33 Scanning Brookfield Viscosity -30°C cps 13,500 Fail 13,600 Temperature @ 30,000 cps -34.1 -18.3 -34.4 Gel Index 6.1 30.2 5.3 The results showed that the formulation containing the polyisobutylene based dispersant, had slightly better MRV-TP-1 (lower viscosity), the same Pour Point (same temperature) and about the same Scanning Brookfield (same viscosity) as the low ethylene, ethylene-butene dispersant. However, the results also showed that low ethylene, ethylene-butene dispersant was superior to the high ethylene, ethylene- butene dispersant, which failed all three tests.

Thus, an oil formulator who chooses to use an ethylene-butene dispersant over a polyisobutylene dispersant to obtain an improvement in low temperature performance as measured by the CCS test, would select a low ethylene, ethylene- butene dispersant, rather than a high ethylene, ethylene-butene dispersant to obtain better MRV, Pour Point and Scanning Brookfield performance, based on the results in Examples 6 and 7.

The invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.