Synthetic hydrocarbon engine oils

Abstract: Non-polymer thickened multigrade engine oils based on synthetic hydrocarbons are provided. The SAE 10W-30 and SAE 15W-40 engine oils are derived from hydrogenated decene-1 oligomer mixtures wherein the oligomers range from C₃₀ up to C₇₀+. Oligomer mixtures of specified oligomer distribution are combined with appropriate performance additives so that the engine oils meet the desired API Service Requirements for gasoline and/or diesel engine usage.

Description: The present invention relates to a non-polymer thickened multigrade engine oil based on synthetic hydrocarbons. More specifically, SAE 10W-30 and SAE 15W-40 engine oils derived from hydrogenated decene-1 oligomers and which do not contain viscosity index improvers are provided. SAE 10W-30 is the engine oil viscosity grade recommended by most manufacturers for gasoline passenger car service whereas, for diesel truck operation, SAE 15W-40 is the most widely recommended engine oil viscosity grade. Both of these oils are multigrade or cross-graded which, in general terms, means that they are acceptable for use in either a summer or winter environment. More precisely, these oils must meet the current SAE J300 APR84 specifications. For an SAE 10W-30 oil, a viscosity of 3.5 Pa.s (3500 centipoise) or below at -20°C as determined in accordance with ASTM D-2602 and a viscosity between 9.3 x 10⁻⁶ and 12,5 x 10⁻⁶ m²/s (9.3 and 12.5 centistokes) at 100°C as determined in accordance with ASTM D-445 is required. Additionally, the oil must have a borderline pumping temperature (ASTM D-3829) of -25°C or below and a stable pour point (FTMS 79lb-203) of -30°C or below. An SAE 15W-40 oil must have a maximum viscosity of 3,5 Pa.s (3500 centipoise) at -15°C, and a viscosity between 12.5 x 10⁻⁶ and 16.3 x 10⁻⁶ m²/s (12,5 and 16,3 centistokes) at 100°C and borderline pumping temperature of -20° or below. In addition to satisfying these viscosity criteria, multigrade engine oils must also meet certain service classifications of the American Petroleum Institute (API). This is accomplished by the addition of appropriate performance additives to the oil. It should be noted that the formulated oil, i.e., the base oil containing all additives, must meet the SAE J-300 APR84 viscosity criteria. To obtain multigrade motor oils using petroleum base stocks, it is also necessary to add a viscosity index (VI) improver. VI improvers are polymeric materials, such as ethylene-propylene copolymers, hydrogenated styrene-diene block copolymers, polyalkyl methacrylates, polyisobutylenes or ethylene-vinyl acetate copolymers, which modify the rate of change of viscosity of the basestock with temperature when added thereto. While the polymeric VI improvers are necessary to achieve cross-grading with petroleum basestocks, the addition of these polymers is not without problem. It is well documented in the prior art that the high molecular weight polymeric VI improvers can undergo shear, i.e., breakdown, under conditions of thermal and mechanical stress. Breakdown of the VI improver alters the viscosity characteristics of the formulated motor oil and can also contribute to the formation of sludge and engine deposits. Field studies have shown, for example, that a SAE 15W-40 diesel engine oil can drop to SAE 15W-30 after only several thousand miles of service. This presents a very real problem with heavy duty over-the-road trucks where it is not uncommon to accumulate 30,000 miles between service intervals. Breakdown of VI improvers is even a problem with gasoline engines, particularly in view of the longer drain intervals which are now being promoted and the fact that today's smaller engines operate at higher RPM's and higher temperatures. The general problems associated with the breakdown of polymeric VI improvers is presented by W. Wunderlich and H. Jost in their entitled "Polymer Stability in Engines", Society of Automotive Engineers, Inc., SAE-429, Paper No. 780372. One approach to overcoming the problems associated with the use of VI improvers is to develop improved polymers which are more resistant to shear under conditions of thermal and mechanical stress. While the development of new polymeric thickeners is a viable approach, it would be even more desirable and advantageous if VI improvers could be totally eliminated from multigrade motor oil formulations. European Patent Applications 88.453; 119,069; and 119,070 disclose multigrade lubricants which are combinations of synthetic fluids having different viscosities. The lubricants consist of blends of high viscosity ethylene-alphaolefin copolymers with lower viscosity synthetic hydrocarhons, such as an alkylated benzene or polyalphaolefin, or enter, such as a monoester, diester or polyester. 5W-40 and 10W-40 oils indicated as being suitable for use as diesel crankcase lubricants obtained by blending different synthetic products are disclosed. US-A-4587368 discloses a process for producing a synthetic lubricant material useful as a base for high performance motor oils. This process minimizes the production of trimer by first forming an intermediate oligomeric mixture and then adding additional monomer thereto in a controller manner for an additional period of time. It is the object of the present invention to provide non-polymer thickened multigrade engine oil suitable for most passenger car and diesel truck service which precludes compatability problems which can be encountered when different basestocks are blended and which also eliminates the need for multiple processes and/or suppliers and otherwise minimizes problems and capital costs associated with storage and transfer or different types of products within a plant. We have now unexpectedly discovered SAE 10W-30 and SAE 15W-40 motor oils obtained from a single synthetic hydrocarbon basestock without the addition of polymeric VI improvers. The multigrade engine oils of the invention are mixtures of conventional oligomers of decene-1 with higher decene-1 oligomers, said oligomers being present in specific proportions. The oligomeric composite is formulated with performance additives to meet the desired API service classification. The present invention provides a non-polymer thickened multi-grade engine oil comprising 80 to 95% by weight of a hydrogenated decene-1 oligomer mixture and 0,5 to 20% by weight of engine performance additives, characterized in that the oligomer mixture contains 0,5% to 20% of C₃₀ oligomer, 43% to 68% of C₄₀ oligomer, 14% to 34% C₅₀ oligomer, 3% to 16% of C₆₀ oligomer and 3% to 16% C₇₀+ oligomers having a viscosity from 9,3 x 10⁻⁶ to 12,5 x 10⁻⁶ m²/s (9, 3 to 12,5 centistokes) at 100°C for a 10 W-30 oil or a viscosity from 12,5 x 10⁻⁶ to 16,3 x 10⁻⁶ m²/s (12,5 to 16,3 centistokes) at 100°C for a 15 W-40 oil. For the multigrade non-polymer thickened lubricants of this invention, significant amounts of hydrogenated hexamer (C₆₀ oligomer), heptamer (C₇₀ oligomer) and higher decene-1 oligomers are present with hydrogenated trimer (C₃₀ oligomer), tetramer (C₄₀ oligomer) and pentamer (C₅₀ oligomer). These compositions are most generally obtained by judicious blending of fractions having different oligomer distributions. However, with proper design and control of process equipment, compositions having oligomer distributions within the specified limits and suitable for formulation with additives to produce non-polymer thickened SAE 10W-30 and SAE 15W-40 engine oils can be obtained directly. Accordingly, the present invention provides a non-polymer thickened multigrade engine oil comprising 80 to 95% by weight of a hydrogenated decene-l oligomer mixture and 0.5 to 20% by weight of engine performance additives characterized by the oligomer mixture containing 0,5% to 20% of C₃₀ oligomer, 43% to 68% of C₄₀ oligomer, 14% to 34% of C₅₀ oligomer, 3% to 16% of C₆₀ oligomer and 3% to 16% C₇₀+ oligomers having a viscosity from 9,3 x 10⁻⁶ to 12,5 x 10⁻⁶ m²/s (9,3 to 12,5 centistokes) at 100°C for a 10W-30 oil or a viscosity from 12,5 x 10⁻⁶ to 16,3 x 10⁻⁶ m²/s (12,5 to 16,3 centistokes) at 100° C for a 15W -40 oil. More specifically, non-polymer thickened SAE 10W-30 oils suitable for use in gasoline engines contain 5% to 10% by weight gasoline engine performance additives which meet the requirements set forth in the appropriate API Engine Service Classification System and 90% to 95% by weight of a hydrogenated decene-1 oligomer mixture containing 0.5% to 20% of C₃₀ oligomer, 43% to 66% of C₄₀ oligomer, 16% to 26% of C₅₀ oligomer, 5% to 11% of C₆₀ oligomer and 5% to 11% of C₇₀+ oligomers. SAE 10W-30 oils suitable for use as diesel engine oils and as universal engine oils contain 10% to 20% by weight universal performance additives which meet the requirements set forth in the appropriate API Engine Service Clasification System and 80% to 90% by weight of a hydrogenated decene-1 oligomer mixture containing 0.5% to 16% of C₃₀ oligomer, 55% to 68% of C₄₀ oligomer, 14% to 23% of C₅₀ oligomer, 3% to 9% of C₆₀ oligomer and 3% to 9% of C₇₀+ oligomers. SAE 15W-40 diesel engine or universal engine oils contain from 10% to 20% by weight diesel or universal performance additives which meet the requirements set forth in the appropriate API Engine Service Classification System with 80% to 90% by weight of a hydrogenated decene-1 oligomer mixture containing up to 2.5% C₃₀ oligomer, 44% to 56% C₄₀ oligomer, 23% to 34% C₅₀ oligomer, 7% to 16% C₆₀ oligomer, and 7% to 16% C₇₀+ oligomers. In accordance with the present invention, cross-graded motor oils suitable for passenger car and diesel truck service are obtained using a single synthetic hydrocarbon basestock, namely polyalphaolefins comprised of specific decene-1 oligomers present in specified amounts. The multigrade engine oils of the invention are obtained without the use of polymeric VI improvers. SAE 10W-30 and SAE 15W-40 engine oils, are obtained simply by addition of appropriate performance additives, i.e., additives which meet the designated API service classification, to the oligomer mixture. Synthetic lubricants derived from alpha-olefins and processes for their production are well known. The polyalphaolefins are obtained using conventional polymerization techniques such as those described in U.S. Patent Nos. 3,149,178; 3,763,244; 3,780,128; 4,045,508; and 4,239,920. These processes generally entail oligomerizing an alpha-olefin, such as octene-1 or decene-1, using a boron trifluoride catalyst in combination with a promoter, such as alcohol or water. Such oligomerization processes typically yield mixtures comprised predominantly of dimer, trimer, tetramer and pentamer. The exact oligomer distribution will vary depending on reaction conditions, however, oligomers above pentamer have heretofore been produced in such small amounts that they typically have not even been reported. As a result of changes in reactor design and better control of process conditions, it is now possible to produce polyalphaolefin products which contain substantial amounts of higher decene-1 oligomers. For example, products containing 20% or more hexamer, heptamer and higher oligomers can consistently be obtained from the decene-1 oligomerization process. In accordance with the present invention, it has now been found that oligomer mixtures containing substantial amounts of higher oligomers can be formulated with suitable performance additives to yield multigrade engine oils without the addition of polymeric viscosity index improvers. SAE 10W-30 and SAE 15W-40 engine oils, the two principal viscosity grades recommended for most passenger car and diesel truck service, can be obtained in this manner. For this invention, specific mixtures of decene-1 oligomers, also referred to as oligomer composite(s), which contain substantial amounts of C₆₀ and higher oligomers are employed. The useful oligomer mixtures are obtained by oligomerizing decene-1 using an alcohol-promoted boron trifluoride catalyst in accordance with the conventional procedures known to the art. It is especially advantageous for the present invention to utilize oligomer mixtures obtained from the oligomerization of decene-1 wherein the catalyst is boron trifluoride promoted with propanol. It will, however, be understood by those skilled in the art that any oligomerization procedure whereby compositions having the hereinafter specified oligomer distributions can be employed. Similarly, whereas all of the oligomeric composites utilized herein are mixtures of decene-1 oligomers, oligomeric products derived from other alpha-olefins in the C₈₋₁₂ range can also be utilized. The ranges specified herein for the oligomer composites derived from decene-1 will not, however, apply to oligomers derived from other olefins. It is possible to obtain the oligomer composite directly from the reactor without further blending. This can be accomplished by controlling the reaction conditions and by proper reactor design. One or more distillation operations may be necessary to achieve the desired oligomer distribution. Also, as with all alpha-olefin derived oligomers used for lubrication applications, the oligomer mixture should be hydrogenated prior to use in order to obtain optimum oxidative and thermal stability. Most generally, the oligomer composite which is combined with the performance additives to obtain the multigrade engine oils of the invention are blends of two or more fractions having different oligomer distributions. A friction rich in lower oligomers is typically blended with a friction rich in higher oligomers to achieve the desired oligomer distribution: however, any combination of fractions which will yield a composite having the required distribution of oligomers is acceptable. The fractions employed for such blending may be different distillation cuts from the same process or may be obtained from entirely different oligomerization processes. A particular fraction may be used in the blending of both SAE 10W-30 and SAE 15W-40 oils. For example, a friction rich in higher oligomers can be blended in one operation with a first fraction rich in lower oligomers to obtain a composite for SAE 10W-30 usage and in another operation with a different lower-oligomer-rich fraction to produce a composite acceptable for SAE 15W-40 usage. If the same lower-oligomer-rich fraction is employed, it is apparent that the proportions of the fractions must be different to produce SAE 10W-30 and SAE 15W-40 oils or that a different high-oligomer-rich fraction must be used. The composite obtained after blending can be hydrogenated or the individual fractions can be hydrogenated before they are blended. The oligomers are hydrogenated using conventional methods known to the art which typically involve combining the oligomer with a suitable hydrogenation catalyst and pressurizing with hydrogen at an elevated temperature. Conventional catalysts, such as platinum or palladium supported on charcoal, Raney nickel, nickel on kieselguhr, and the like, are employed. Pressures can range from about several hundred kPa up to about 13790 kPa (several hundred up to about 2000 psig) and temperatures range from about 50°C to about 3000°C. The hydrogenation is terminated when the desired bromine number is achieved, typically less than 1. Oligomer composites having specific oligomer distributions are necessary if engine oils which are cross-graded without the addition of VI improvers are to be obtained. Additionally, performance additives must be included in the formulation to obtain the desired service rating. An SAE 10W-30 or SAE 15W-40 engine oil which meets the manufacturer's specifications therefore requires both the proper selection of oligomers and additives -- the oligomer combination to impart the desired viscosity characteristics and the additives to impart the necessary service characteristics. Acceptable formulations cannot be obtained when either the specified oligomer composite or the specified additives are not used. While SAE 10W-30 and SAE 15W-40 are the broadest multigrade formulations possible, it will be understood by those skilled in the art that narrower multigrade oils within the broader viscosity range are also possible. For example, SAE 15W-30 and SAE 10W-20 formulations can also be obtained and are within the scope of SAE 10W-30 even though the former grades are not specifically referenced. This aspect of the invention can be better understood by reference to the following table wherein viscosity requirements for multigrade engine oils described by the SAE Engine Oil Viscosity Classification -- SAE J300 APR84 are provided. SAE GRADE MAXIMUM VISCOSITY [Pa.s (centipoise)] AT TEMPERATURE (°C) VISCOSITY AT 100°C m²/s (centistoke) BORDERLINE PUMPING TEMPERATURE STABLE POUR POINT Min. Max. 0W 3,25 (3250) at -30 3,8.10⁻⁶ (3.8) - -35°C 5W 3,5 (3500) at -25 3,8.10⁻⁶ (3.8) - -30°C -35°C 10W 3,5 (3500) at -20 4,1.10⁻⁶ (4.1) - -25°C -30°C 15W 3,5 (3500) at -15 5,6.10⁻⁶ (5.6) - -20°C 20W 4,5 (4500) at -10 5,6.10⁻⁶ (5.6) - -15°c 25W 6,0 (6000) at -5 9,3.10⁻⁶ (9.3) - -10°C 20 5,6.10⁻⁶ (5.6) 9,3.10⁻⁶(9.3) 30 9,3.10⁻⁶ (9.3) 12,5.10⁻⁶ (12.5) 40 12,5.10⁻⁶ (12.5) 16.3.10⁻⁶ (16.3) 50 16,3.10⁻⁶ (16.3) 21.9.10⁻⁶ (21.9) In one embodiment of the invention SAE 10W-30 engine oils which do not contain polymeric viscosity index improvers and which meet the appropriate API "S" Service Classification for gasoline engines are provided. These Service Categories include, most notably, SC, SD, SE, and SF. Oils meeting API Service Classification SF are the most important since they may be used where API Service Categories SE, SD or SC are recommended. Thus, where a specific Service Category is referred to herein, all prior Service Categories which have less stringent engine test requirements are also included. The SAE 10W-30 engine oils suitable for use in gasoline engines contain 5% to 10% by weight gasoline engine performance additives so that the oil meets the API "S" Service requirements and 90% to 95% by weight of a hydrogenated decene-1 oligomer mixture containing 0.5% to 20% C₃₀ oligomer, 43% to 66% C₄₀ oligomer, 16% to 26% C₅₀ oligomer, 5% to 11% C₆₀ oligomer and 5% to 11% C₇₀+ oligomers. Percentages reported herein for oligomers are area percentages determined by conventional gas-liquid chromatographic methods. Generally, these engine oils are formulated with a performance additive package which meets the desired API "S" Service Rating, most typically, API Service Rating SF. Performance additive packages are commercially available and widely used in the manufacture of engine oils. These packages are formulated to contain the necessary corrosion inhibitors, detergents, dispersants, antiwear additives, defoamers, antioxidants, metal passivators and other adjuvants required to obtain a useful motor oil of the desired quality, i.e., meeting the desired API Service Rating. The use of these additive packages greatly simplifies the task of the formulator. Highly useful SAE 10W-30 engine oils suitable for use in gasoline engines are obtained when the oligomer composite contains 2% to 17% C₃₀ oligomer, 45% to 63% C₄₀ oligomer, 18% to 24% C₅₀ oligomer, 6% to 10% C₆₀ oligomer, and 6% to 10% C₇₀+ oligomers. In another embodiment of this invention non-polymer thickened SAE 10W-30 engine oils suitable for use in diesel engines, i.e., meeting the appropriate API "C" Commercial Classification, are also provided. The most common oils of this type are those having API Service Ratings CC and CD. In addition to meeting the service requirements for diesel engines, these SAE 10W-30 oils can also meet API "S" Service requirements. These latter types of "dual service" or "universal" engine oils have API Service Designations CD/SD, CD/SE, CC/SE, CC/SF, and CD/SF. Such universal oils are widely used by individuals with mixed fleets, i.e., gasoline engine vehicles and lighter duty diesel engine vehicles, such as automobile diesel engines. This facilitates servicing since only one engine oil suitable for use in both types of vehicles need be inventoried. The SAE 10W-30 diesel and universal engine oils contain 10% to 20% by weight performance additives so that the formulated oil meets the appropriate API Service requirements and 80% to 90% by weight of a hydrogenated decene-1 oligomer mixture containing 0.5% to 16% C₃₀ oligomer, 55% to 68% C₄₀ oligomer, 14% to 23% C₅₀ oligomer, 3% to 9% C₆₀ oligomer, and 3% to 9% C₇₀+ oligomers. Most advantageously, the oligomer composite will contain 2% to 13% C₃₀ oligomer, 57% to 65% C₄₀ oligomer, 16% to 21% C₅₀ oligomer, 4% to 8% C₆₀ oligomer, and 4% to 8% C₇₀+ oligomers. As previously indicated, the performance additives are most generally incorporated into the oil by the addition of an available additive package. The oil may, however, be formulated by the addition of the individual additive components. In either case the result is the same, that is, the engine oil contains the requisite amount of the necessary additives to achieve the desired API Services Rating. The useful additive packages and the individual additives are known and commercially available. Commercial additive packages are formulated to contain the necessary detergents, dispersants, corrosion/rust inhibitors, antioxidants, antiwear additives, defoamers, metal passivators, set point reducers, to meet a specific API Service Rating when employed at the recommended usage level. They do not, however, contain viscosity index improvers. While it is not generally necessary, additional additives may be employed in conjunction with these additive packages. Most additive manufacturers supply a line of additive packages to meet the full range of service requirements for gasoline engine oils, diesel engine oils, and universal oils. For example, Ethyl Petroleum Additives Division provides a complete line of products which are sold under the trademark HiTEC. The following is a list of the various HiTEC additive packages and the recommended API Service Rating for each: HiTEC 918 - SF, HiTEC 850C - CD, HiTEC 909 - SF/CC, HiTEC 910 - SF/CC, HiTEC 914 - SF/CC, HiTEC 920 - SF/CC, HiTEC 2000 - SF/CC, HiTEC 2001 - SF/CD, HiTEC 854 - SF/CD, HiTEC 861 - SF/CD, HiTEC 862 - SF/CD, HiTEC 865 - SF/CD. Similar additive packages are available from other manufacturers. For example, the following are representative universal additive packages: TLA-654A (SF/CD), TLA-668 (SF/CC) , and TLA-679 (SF/CD) manufactured by Texaco Chemical Company; OLA 8150A (SF/CD), OLA 8363C (SF/CC), OLA 8373 (SF/CC), OLA 8718 (SF/CD) , and OLA 8730 (SF/CD) manufactured by Chevron Chemical Company, Oronite Additives Division; Lubrizol (trademark) 7574 (SF/CC) and Lubrizol 3978 (SF/CD) manufactured by The Lubrizol Corporation; and Amoco (trademark) 6688 (SF/CD), 6689 (SF/CD), 6817 (SF/CC), and 6831 (SF/CC) manufactured by Amoco Petroleum Additives Company. Other additive packages with different API service ratings are available from the aforementioned manufacturers and other suppliers. The dosage level employed will vary depending on the particular additive package used. For example, optimal usage levels for SAE 15W-40 engine oils with the five HiTEC SF/CD rated packages range from about 11.5 percent to 14.7 percent. Variations in oligomer distribution may require adjustments of the dosage level even within the same SAE grade. Even when an additive package is employed for the formulation, one or more other additives may still be employed. If desired, individual additive components including known antioxidants, dispersants, detergents, metal passivators, rust/corrosion inhibitors, setting point reducers, friction reducing agents can be compounded with the oligomer composite to obtain the engine oil. Useful antioxidants include substituted aromatic amines, such as dioctyldiphenylamine, mono-t-octylphenylnaphthylamines, dioctylphenothiazine, phenyl- -naphthylamine, N,N'-di-butyl-p-phenylenediamine and the like; hindered phenols, such as 2,6-di-t-butyl-p-cresol, 4,4'-bis-(2,6-diisopropylphenol), 2,2'-thio-bis-(4-methyl-6-t-butylphenol), 4,4'-methylene-bis-(2,6-di-t-butylphenol); organic phosphites, such as trinonyl phosphite, triphenyl phosphite; esters of thiodipropionic acid, such as dilauryl thiodipropionate. Representative detergents and dispersants include polyalkenylsuccinimides and oil-soluble metal soaps, such as Ca, Ba, Mg and Al carboxylates, phenates and sulfonates. Useful metal passivators include benzotriazole, 2-mercaptobenzotriazole, 2,5-dimercaptothiadiazole, salts of salicylaminoguanidine, quinizarin and propyl gallate. Useful rust/corrosion inhibitors include primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids; oil-soluble alkylammonium carboxylates; substituted imidazolines and oxazolines; alkali metal and alkaline earth metal carbonates; alkali metal and alkaline earth metal salts of alkylbenzene sulfonic acids, such as barium dinonylnaphthalenesulfonates, calcium petroleumsulfonates; esters, anhydrides, and metal salts of organic acids, such as sorbitan monooleate, lead naphthenate, and dodecylsuccinic anhydride. Set point reducers can include alkylated naphthalenes, alkylated phenols and polymethacrylates. Anti-wear additives can include sulfur, phosphorus, and halogen-containing compounds, such as sulfurised vegetable oils, zinc dialkyl dithiophosphates, chlorinated paraffins, alkyl and aryl disulfides. Multifunctional additives such as those described in U.S. Patent Nos. 3,652,410, 4,162,224, and 4,534,872 can also be utilized for the formulation of these engine oils. The amount of the individual additives will vary and is dictated by the particular application and the service requirement desired. The total amount of the additives, however, falls within the above-prescribed weight percent limits specified for each of the engine oils. The following examples illustrate the engine oil formulations of the present invention more fully. In these examples all parts are on a weight basis. Hydrogenated decene-1 oligomer mixtures were employed throughout as the basestocks for the formulations. Oligomer distributions were determined by conventional gas-liquid chromatographic (GLC) methods using a glass column [3' x 2mm 1 percent SP-2100 on 100-120 Superlcoport (trademark)]. Oligomer distributions are reported throughout as area percentages. The injector temperature was maintained at 300°C and the flame ionization detector at 375°C. Nitrogen was used as the carrier gas at a rate of 30 cm³/min. The oven temperature was increased at a rate of 15°C/min over the range 140°C to 350°C and then maintained at 350°C for 10 minutes. Separation of decene-1 oligomers above C₇₀ is not possible employing this technique. For this reason, the last oligomer fraction is reported as C₇₀+ since it may also contain small amounts of oligomers higher than C₇₀, primarily C₈₀ and C₉₀ oligomers. Viscosities reported in the examples and identified as the Cold Crank Simulator (CCS) viscosity and 100°C viscosity are determined in accordance with ASTM D-2602 and ASTM D-445 per SAE J300 APR84 specifications. CCS viscosities are reported in Pa·s (centipoise) at the specified temperatures (°C) whereas 100°C viscosities are reported in m²/s (centistokes). EXAMPLE I A non-polymer thickened SAE 10W-30 gasoline engine oil having an API Service Rating SF was prepared using a mixture of hydrogenated decene-1 oligomers. The oligomer composite employed as the basestock was obtained by blending two different polyalphaolefin synthetic hydrocarbon fluids. The first fluid contained 4.8 percent C₃₀ oligomer, 63.7 percent C₄₀ oligomer, 18.7 percent C₅₀ oligomer, 6.5 percent C₆₀ oligomer, and 6.3 percent C₇₀+ oligomer. The second fluid, which contained significantly higher amounts of the higher oligomers, contained 54.7 percent C₄₀ oligomer, 24.5 percent C₅₀ oligomer, 10.0 percent C₆₀ oligomer, and 10.8 percent C₇₀+ oligomers. The first and second fractions were blended at a 1:1 ratio to produce an oligomer composite containing 2.40 percent C₃₀ oligomer, 59.2 percent C₄₀ oligomer, 21.6 percent C₅₀ oligomer, 8.3 percent C₆₀ oligomer, and 8.6 percent C₇₀+ oligomer. The oligomer composite (92.20 parts) was combined with 7.80 parts low ash gasoline engine performance additive package (Lubrizol (trademark) 7574] meeting API SF requirements. The resulting formulated oil had a 100°C viscosity of 10,09 x 10⁻⁶m²/s (10.09 centistokes) and CCS viscosity at 20° C of 3,29 Pa·s (3290 centipoise). The oil also met the Borderline Pumping Temperature requirements and stable pour point requirements of SAE J300 APR84 for SAE grade 10W, thus fully qualifying it as a cross-graded 10W SF engine oil. EXAMPLE II To further demonstrate the ability to obtain an SAE 10W-30 engine oil an oligomer composite was prepared by blending the polyalphaolefin synthetic hydrocarbon fluids of Example I. The first and second hydrocarbon fluids were combined in a ratio of 3.5:1 and 90 parts of the resulting oligomer composite (3.73% C₃₀ oligomer, 61.40% C₄₀ oligomer, 19.70% C₅₀ oligomer, 7.06% C₆₀ oligomer, and 8.58% C₇₀+ oligomer) was formulated with 1.36 parts of a calcium alkylphenate detergent, 5.40 parts alkenyl succinimide ashless dispersant, 1.57 parts alkyl zinc dithiophosphate antioxidant/antiwear additive, 0.30 part thiodiethylene bis-(3,5-di-t-butyl-4-hydroxyhydrocinnamate antioxidant, 0.30 part alkylated phenyl-naphthylamine antioxidant, 0.05 part copper deactivator, 0.02 part antifoaming agent (10% silicon in toluene) and 1.00 part overbased calcium sulfonate detergent/rust inhibitor. The resulting formulated oil had a 100°C viscosity of 9,30 x 10⁻⁶ m²/s (9.30 centistokes) and CCS viscosity at -20°C of 3,0 Pa.s (3000 centipoise). The non-polymer thickened oil met all of the SAE J300 APR 84 requirements for 10W-30 oils. A basestock obtained by blending the first and second polyalphaolefin synthetic hydrocarbon fluids at a ratio of approximately 1:1.25 was also identically formulated to provide an SAE 10W-30 engine oil. The 100°C and CCS (-20°C) viscosities for the formulated oil were 10,0 x 10⁻⁶ (10.0) and 3,5 (3500), respectively. EXAMPLE III In accordance with the general procedure of Example I, an SAE 10W-30 SF engine oil was obtained using a polyalphaolefin synthetic hydrocarbon basestock without the addition of polymeric viscosity index improvers. The oil contained 92.20 parts polyalphaolefin basestock and 7.80 parts of the API SF gasoline engine performance additive package. The oligomer distribution of the basestock and 100°C viscosity and CCS viscosity at -20°C of the resulting formulated engine oil were as follows: % C₃₀ oligomer 4.1 % C₄₀ oligomer 62.4 % C₅₀ oligomer 19.6 % C₆₀ oligomer 7.0 % C₇₀+ oligomer 7.0 Viscosity: 100°C 9,39x10⁻⁶ (9.39) CCS (-20°C) 2,69 (2690) The formulation fully met the viscosity requirements of SAE J300 APR84 for 10W-30 oils. EXAMPLES IV AND V Additional non-polymer thickened SAE 10W-30 SF engine oils were prepared using basestock comprised of mixtures of decene-1 oligomers. The basestocks were obtained by blending two polyalphaolefin synthetic hydrocarbon fluids. The first fluid contained 84.9 percent C₃₀ oligomer and 14.8 percent C₄₀ oligomer. The second fluid was the same as that described in Example I. The API SF performance additive package was also the same as used in Example I. Compositions of the engine oils, including the overall oligomer distribution of the resulting synthetic hydrocarbon blends, were as follows: EX. IV EX. V First Hydrocarbon Fluid (Parts) 18.44 11.53 Second Hydrocarbon Fluid (Parts) 73.76 80.68 Oligomer Distribution of Blend: % C₃₀ oligomer 17.0 10.6 % C₄₀ oligomer 46.7 49.4 % C₅₀ oligomer 18.6 21.3 % C₆₀ oligomer 8.0 8.7 % C₇₀+ oligomer 8.6 9.4 Additive Package (Parts) 7.80 7.80 The formulated oil of Example IV had a 100°C viscosity of 9,31.10⁻⁶m²/s (9.31 centistokes) and CCS (-20°C) viscosity of 2,81 Paxs (2810 centipoise). The formulated oil of Example V had a 100°C viscosity of 10.10⁻⁶m²/s (10.00 centistokes) and CCS (-20°C) viscosity of 3,2 Pa·s (3200 centipoise). EXAMPLES VI-X Non-polymer thickened SAE 10W-30 SF/CD universal engine oils suitable for use in both gasoline and diesel engines were prepared. For these formulations, 86.31 parts polyalphaolefin synthetic hydrocarbon basestocks comprised of mixtures of decene-1 oligomers were combined with 13.69 parts performance additive package meeting API SF/CD service requirements [Lubrizol (trademark) 3978]. The oligomer distribution of each basestock and the 100°C and CCS (-20°C) viscosities for the resulting formulated engine oils were as follows: EX. VI EX. VII E. VIII EX. IX EX. X % C₃₀ oligomer 3.8 4.0 4.3 4.8 11.7 % C₄₀ oligomer 61.9 62.3 62.7 63.7 59.9 % C₅₀ oligomer 19.9 19.6 19.3 18.7 17.7 % C₆₀ oligomer 7.2 7.1 6.9 6.5 6.0 % C₇₀+ oligomer 7.2 7.0 6.8 6.3 4.7 Viscosity: 100°C 10,36.10⁻⁶ 10,25.10⁻⁶ 10,14x10⁻⁶ 9.92x10⁻⁶ 9,39x10⁻⁶ (10.36) (10.25) (10.14) (9.92) (9.39) CCS (-20°C) 3,40 3,22 3,13 3,27 2,3 (3400) (3220) (3130) (3270) (2300)

Claims: A non-polymer thickened multi-grade engine oil comprising 80 to 95% by weight of a hydrogenated decene-1 oligomer mixture and 0,5 to 20% by weight of engine performance additives, characterized in that the oligomer mixture contains 0,5% to 20% of C₃₀ oligomer, 43% to 68% of C₄₀ oligomer, 14% to 34% C₅₀ oligomer, 3% to 16% of C₆₀ oligomer and 3% to 16% C₇₀+ oligomers having a viscosity from 9,3 x 10⁻⁶ to 12,5 x 10⁻⁶ m²/s (9,3 to 12,5 centistokes) at 100°C for a 10 W-30 oil or a viscosity from 12,5 x 10⁻⁶ to 16,3 x 10⁻⁶ m²/s (12,5 to 16,3 centistokes) at 100°C for a 15 W-40 oil. The non-polymer thickened engine oil of claim 1, wherein the oil is a SAE 1OW-30 gasoline engine oil comprising 90% to 95% by weight of a hydrogenated decene-1 oligomer mixture and 5% to 10% by weight of gasoline engine performance additives, said oligomer mixture containing 0,5 % to 20% of C₃₀ oligomer, 43% to 66% of C₄₀ oligomer, 16% to 26% of C₅₀ oligomer, 5% to 11% of C₆₀ oligomer and 5% to 11% of C₇₀+ oligomers. The non-polymer thickened engine oil of claim 1 or 2, wherein the oil meets the requirements of API Service Category SF. The non-polymer thickened engine oil of claim 1 or 2, wherein the oligomer mixture contains 2% to 17% of C₃₀ oligomer, 45% to 63% of C₄₀ oligomer, 18% to 24% of C₅₀ oligomer, 6% to 10% of C₆₀ oligomer and 6% to 10% of C₇₀+ oligomers. The non-polymer thickened engine oil of claim 1 which is a SAE 1OW-30 universal or diesel engine oil comprising 80 to 90% by weight of a hydrogenated decene-1 oligomer mixture and 10% to 20% by weight of universal or diesel engine performance additives, said oligomer mixture containing 0,5% to 16% of C₃₀ oligomer, 55% to 68% of C₄₀ oligomer, 14% to 23% of C₅₀ oligomer, 3% to 9% of C₆₀ oligomer and 3% to 9% of C₇₀+ oligomers. The non-polymer thickened engine oil of claim 5 which meets the requirements of API Service Category CD. The non-polymer thickened engine oil of claim 5 which meets the requirements of API Service Categories SF and CD. The non-polymer thickened engine oil of any of claims 5 to 7 wherein the oligomer mixture contains 2% to 13% of C₃₀ oligomer, 57% to 65% of C₄₀ oligomer, 16% to 21% of C₅₀ oligomer, 4% to 8% of C₆₀ oligomer and 4% to 8% of C₇₀+ oligomers. Use of the non-polymer thickned engine oil according to claim 1 a a multi-grade oil.

Inventors: BEIMESCH BRUCE J, DAVIS JAMES E, BEIMESCH, BRUCE J., DAVIS, JAMES E.
Applicants: ETHYL CORP, ETHYL CORPORATION
Application year: 1988
Main classification: C10M107
IPC codes: C10M107, C10N40, C10M171, C10N30, C10M169, F02B3, C10N20