Lubricating oil compositions for fuel economy retention

Abstract

A method for preserving fuel economy properties of lubricating oil composition is described. The method involves providing a lubricating oil composition that includes at least one base oil and a mixture of esters. The mixture includes monoglycerides, diglycerides, and triglycerides and includes 40% to 55% C12 esters and 10% to 25% C14 esters, and 5% to 20% C16 esters.

Description

[0001] LUBRICATING OIL COMPOSITIONS FOR FUEL ECONOMY RETENTION CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 671,327, filed July 15, 2024, which is incorporated by reference herein in its entirety. FIELD OF DISCLOSURE

[0002] This disclosure relates to lubricating oil compositions and methods of using the same. More specifically, this disclosure describes methods for improving fuel economy retention. BACKGROUND

[0003] The lubrication of moving engine parts is crucial as it reduces friction and wear, which in turn contributes to fuel savings. The exact lubricant formulation used in motor vehicles directly impacts fuel consumption. Improving the performance levels of these fuel economy enhancing lubricants is imperative, but it is also critically important to maintain or preserve their fuel economy performance over time, ensuring it does not diminish between oil changes or after a certain mileage, as any reduction in performance directly impacts the benefits they offer. Thus, the challenge lies not only in achieving a higher level of fuel economy performance but also in sustaining it throughout the lubricant's lifespan. SUMMARY OF THE INVENTION

[0004] In one aspect, there is provided a method for preserving fuel economy properties of lubricating oil composition, the method comprising providing a lubricating oil composition that - 1 - EMF_US 86880356v1 includes: at least one base oil; and a mixture of esters, wherein the mixture includes monoglycerides, diglycerides, and triglycerides; and wherein the mixture of esters includes 40% to 55% C12esters and 10% to 25% C14esters, and 5% to 20% C16esters.

[0005] In another aspect, there is provided a use of mixture of esters to preserve fuel economy in a lubricating oil composition, wherein the lubricating oil composition includes: at least one base oil; and a mixture of esters, wherein the mixture includes monoglycerides, diglycerides, and triglycerides; and wherein the mixture of esters includes 40% to 55% C12esters and 10% to 25% C14esters, and 5% to 20% C16esters. DETAILED DESCRIPTION Definitions

[0006] The following terms will be used throughout the specification and will have the following meanings unless otherwise indicated.

[0007] The term “a major amount” of a base oil refers to where the amount of the base oil is at least 40 wt. % of the lubricating oil composition. In some embodiments, “a major amount” of a base oil refers to an amount of the base oil more than 50 wt. %, more than 60 wt. %, more than 70 wt. %, more than 80 wt. %, or more than 90 wt. % of the lubricating oil composition. Description

[0008] This disclosure relates to a lubricating oil composition comprising at least one base oil and a friction modifier system. In addition to improving fresh oil economy, it has been discovered that the lubricating oil compositions of this disclosure improve fuel economy retention in internal combustion engines (i.e., preserves fuel economy in internal combustion engines).

[0009] In another aspect, the friction modifier system described herein imparts certain advantageous properties to a lubricating oil composition. These include improving the fuel economy performance of the lubricating oil composition and / or preserving the fuel economy performance of the lubricating oil composition over time. Friction Modifier System

[0010] The lubricating oil composition includes a friction modifier system that has been finely tuned to provide fuel economy benefits (e.g., fuel economy retention of used oil) as demonstrated in the Examples section.

[0011] In accordance with the present disclosure, the friction modifier system is a mixture of ester compounds. The mixture of ester compounds can include mono-, di-, and tri-ester compounds. In particular, the mixture of ester compounds are various forms of glycerides (i.e., monoglycerides, diglycerides, and triglycerides).

[0012] As used herein, “glycerides” are esters of glycerol (a trihydric alcohol) and fatty acids in which one or more of the hydroxyl groups of glycerol are esterified with the carboxyl groups of fatty acids containing 8 to about 20 carbon atoms, preferably from 10 to 16 carbon atoms. The fatty acids can be saturated or unsaturated, linear, branched or cyclic monocarboxylic acids. Where three hydroxyl groups are esterified, the resulting glyceride is denoted a “triglyceride”. When only one or two of the hydroxyl groups are esterified, the resulting products are denoted “monoglycerides” and “diglycerides”, respectively.

[0013] Natural glycerides include, e.g., palm oil, tall oil, tallow (animal-based, coconut oil, and soybean oils. Synthetically produced glycerides can be synthesized by the condensation reaction between glycerol and a fatty acid or mixture of fatty acids containing from about 8 to about 20 carbon atoms.

[0014] In particular, the glyceride can be represented by the following generalized structure: O R1 wherein R1, R2, and R3are independently H, alkyl, or alkenyl group; and n and n’ is independently 0 or 1. When n and n’ are both 0, the glyceride is a monoglyceride. When only one of n and n’ is 0, the glyceride is a diglyceride. When n and n’ are both 1, the glyceride is a triglyceride.

[0015] In some embodiments, the mixture includes glycerides that comprises 40% to 55% of C12esters, 10% to 25% of C14esters, and 5% to 20% of C16esters. Remainder ester groups can be C8, C10, C18, or C20 esters. This carbon number distribution can be measured by, for example, gas chromatography / mass spectrometry (GC / MS).

[0016] In some embodiments, the mixture includes 20-55% (by weight) of monoglycerides as measured by GC / MS and electrospray ionization mass spectrometry (ESI / MS). In some embodiments, the mixture includes 20-40% (by weight) of diglycerides as measured by GC / MS and ESI / MS.

[0017] Tri-ester, di-ester, and monoester versions of glycerides are shown below: O 0

[0002]

[0018] In some embodiments, the ester compounds are fatty acid esters. Examples of fatty acid esters include esters of lauric acid (C12), myristic acid (C14), palmitic acid (C16), palmitoleic acid (C16), capric acid (C10), caprylic acid (C8), oleic acid (C18), or mixtures thereof. Specific examples of glycerides include lauric acid glycerides, myristic acid glycerides, palmitic acid glycerides, or mixture thereof.

[0019] In general, the friction modifier system is present in an amount sufficient to provide desired degree of fuel economy benefit. In some embodiments, the esters of the friction modifier system are present in 0.05 wt.% to 1.0 wt.% based on the total lubricating oil composition, such as 0.05 wt.% to 0.9 wt.%, 0.05 wt.% to 0.8 wt.%, 0.05 wt.% to 0.7 wt.%, 0.05 wt.% to 0.6 wt.%, 0.05 wt.% to 0.5 wt.%, 0.1 wt.% to 1.0 wt.%, 0.1 wt.% to 0.9 wt.%, 0.1 wt.% to 0.8 wt.%, 0.1 wt.% to 0.7 wt.%, 0.1 wt.% to 0.6 wt.%, 0.1 wt.% to 0.5 wt.%, 0.2 wt.% to 1.0 wt.%, 0.2 wt.% to 0.9 wt.%, 0.2 wt.% to 0.8 wt.%, 0.2 wt.% to 0.7 wt.%, 0.2 wt.% to 0.6 wt.%, and 0.2 wt.% to 0.5 wt.%. The Oil of Lubricating Viscosity

[0020] The oil of lubricating viscosity (sometimes referred to as “base stock” or “base oil”) is the primary liquid constituent of a lubricant, into which additives and possibly other oils are blended, for example to produce a final lubricant (or lubricant composition).

[0021] The lubricating oil compositions disclosed herein generally comprise at least one oil of lubricating viscosity. Any base oil known to a skilled artisan can be used as the oil of lubricating viscosity disclosed herein. Some base oils suitable for preparing the lubricating oil compositions have been described in Mortier et al., "Chemistry and Technology of Lubricants," 2nd Edition, London, Springer, Chapters 1 and 2 (1996); and A. Sequeria, Jr., "Lubricant Base Oil and Wax Processing," New York, Marcel Decker, Chapter 6, (1994); and D. V. Brock, Lubrication Engineering, Vol.43, pages 184-5, (1987), all of which are incorporated herein by reference.

[0022] A base oil is useful for making concentrates as well as for making lubricating compositions therefrom and may be selected from natural and synthetic lubricating oils and combinations thereof.

[0023] Natural oils include animal and vegetable oils, liquid petroleum oils and hydrorefined, solvent-treated mineral lubricating oils of the paraffinic, naphthenic and mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful base oils.

[0024] Synthetic lubricating oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, poly(1-hexenes), poly(1-octenes), poly(1-decenes); alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)benzenes; polyphenols (e.g., biphenyls, terphenyls, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogues and homologues thereof. Polymerized olefins can also be derived from bio-derived sources such as hydrocarbon terpenes such as myrcene, ocimene and farnesene which can also be co-polymerized with other olefins and further isomerized if desired.

[0025] Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids (e.g., malonic acid, alkyl malonic acids, alkenyl malonic acids, succinic acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, phthalic acid) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

[0026] Esters useful as synthetic oils also include those made from C5 to C12 monocarboxylic acids and polyols, and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol. Esters from bio-derived sources may also be useful as synthetic oils.

[0027] The base oil may be derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. For example, the hydrocarbons may be hydroisomerized; hydrocracked and hydroisomerized; dewaxed; or hydroisomerized and dewaxed; using processes known to those skilled in the art.

[0028] The base oil may be a renewable or bio-derived base oil. Examples of such base oils are disclosed in WO2016061050 and US20190338211, which is incorporated herein by reference. According to some embodiments, the renewable or bio-derived base oil includes a biobased hydrocarbon, such as an isoparaffinic hydrocarbon derived from hydrocarbon terpenes, such as myrcene, ocimene, and farnesene. In some embodiments, the biobased hydrocarbon is produced from fatty acids or fatty esters.

[0029] Unrefined, refined and re-refined oils can be used in the present lubricating composition. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from distillation or ester oil obtained directly from an esterification process and used without further treatment would be unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration and percolation are known to those skilled in the art.

[0030] By applying similar refining processes to already-refined oils that have been used in service as those processes that are used to obtain those refined oils in the first place, re-refined oils may be obtained. Such re-refined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques for approval of spent additive and oil breakdown products.

[0031] Hence, the base oil which may be used to make the present lubricating composition may be selected from any of the base oils in Groups I-V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). Such base oil groups are summarized in Table 1 below: Table 1 Base Oil Properties (a)Determined in accordance with ASTM D2007.(b)Determined in accordance with ASTM D2622, ASTM D3120, ASTM D4294 or ASTM D4927.(c)Determined in accordance with ASTM D2270.

[0032] Base oils suitable for use herein are any of the variety corresponding to API Group II, Group III, Group IV, and Group V oils and combinations thereof. In one embodiment, the base oil is a Group I base oil or a blend of two or more different Group I base oils. Suitable Group I base oils include any light overhead cuts from a vacuum distillation column, such as, for example, any Light Neutral, Medium Neutral, and Heavy Neutral base stocks. The base oil may also include residual base stocks or bottoms fractions such as bright stock. Bright stock is a high viscosity base oil which has been conventionally produced from residual stocks or bottoms and has been highly refined and dewaxed.

[0033] In one embodiment, the base oil is a Group II base oil or a blend of two or more different Group II base oils. Suitable Group II base oils include, for example, paraffinic mineral oils obtained by a suitable combination of refining processes such as hydrorefining and dewaxing in respect of lubricating oil fractions obtained by atmospheric distillation of crude oil.

[0034] Depending on the usage case, the base oil may be present in 1 wt.% to 99 wt.% based on the total weight of the lubricating oil composition. For example, in finished oils, the base oil or base oil(s) are present in a major amount based on the total weight of the lubricating oil composition. In concentrates (e.g., oil additive package), the amount of base oil(s) will be generally less. Other Additives

[0035] Optionally, the lubricating oil composition may further comprise an additive that can impart or improve any desirable property of the lubricating oil composition. Any additive known to a person of ordinary skill in the art may be used in the lubricating oil compositions disclosed herein. Some suitable additives have been described in Mortier et al., "Chemistry and Technology of Lubricants," 2nd Edition. London, Springer, (1996); and Leslie R. Rudnick, "Lubricant Additives: Chemistry and Applications," New York, Marcel Dekker (2003), both of which are incorporated herein by reference. In some embodiments, the additive can be selected from the group consisting of antioxidants, antiwear agents, detergents, rust inhibitors, demulsifiers, friction modifiers, multi-functional additives, viscosity index improvers, pour point depressants, foam inhibitors, metal deactivators, dispersants, corrosion inhibitors, lubricity improvers, thermal stability improvers, anti-haze additives, icing inhibitors, dyes, markers, static dissipaters, biocides and combinations thereof.

[0036] In general, the concentration of each of the additives in the lubricating oil composition, when used, may range from about 0.001 wt. % to about 10 wt. %, from about 0.01 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 2.5 wt. %, based on the total weight of the lubricating oil composition. Further, the total amount of the additives in the lubricating oil composition may range from about 0.001 wt. % to about 20 wt. %, from about 0.01 wt. % to about 10 wt. %, or from about 0.1 wt. % to about 5 wt. %, based on the total weight of the lubricating oil composition.

[0037] The following examples are presented to exemplify embodiments but are not intended to limit the application to the specific embodiments set forth. Unless indicated to the contrary, all parts and percentages are by weight. All numerical values are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the application. Specific details described in each example should not be construed as necessary features. EXAMPLES

[0038] The following examples are intended for illustrative purposes only and do not limit in any way the scope. Contents of examples are described below. Also provided are test method(s) used in evaluation of the examples. Comparative Example 1 (Baseline Formulation)

[0039] A baseline SAE 0W-20 lubricating oil was prepared by blending the following components with Group III base oil: a) primary and secondary zinc dithiophosphate b) mixture of succinimide dispersants c) diphenylamine antioxidant d) mixture of calcium and magnesium detergents e) pour point depressant f) viscosity index improver g) foam inhibitor Example 1

[0040] Example 1 includes the baseline formation and 0.3 wt.% of a mixture of mono-, di- , and tri- esters of glycerol. The mixture includes esters having from 40% to 55% C12 esters, 10% to 25% C14 esters, and 5% to 20% C16 esters. In general, the monoesters and di-esters of glycerol are the most prominent components in the mixture,. Comparative Example 2

[0041] Comparative Example 2 includes the baseline formation and 0.3 wt.% of C16-18 (even numbered) and C18-unsaturated, esters with pentaerythritol. Comparative Example 3

[0042] Comparative Example 3 includes the baseline formation and 0.3 wt.% of tall oil hydroxyethylimidazoline. Comparative Example 4

[0043] Comparative Example 4 includes the baseline formation and 0.3 wt.% of a mixture of mono-, di- and triesters of triethanolamine and tallow fatty acid. Comparative Example 5

[0044] Comparative Example 5 includes the baseline formation and 0.3 wt.% of N, N- bis(2-hydroxypropyl) tallow amides. The tallow portion is a mixture of mostly C14, C16 and C18 with unsaturation. Comparative Example 6

[0045] Comparative Example 6 includes the baseline formation and 0.3 wt.% of glycerol monooleate (at least 50 wt.% of mono-ester content). Sequence VIE Engine Test (ASTM D8114)

[0046] The oil samples were also evaluated using Sequence VIE Engine Test (ASTM D8114), which provides a comparative fuel economy index (FEI) of the fuel-saving capabilities of automotive engine oils under repeatable laboratory conditions. Fuel consumption is measured for several speed / load / temperature conditions and compared against a baseline lubricant.

[0047] The candidate lubricant is introduced and aged for an initial period of time (~16 hours) and tested for fuel economy - FEI1. The candidate lubricant is left in the engine and aged for additional period of time (~109 hours) and tested again for fuel economy - FEI2. FEI SUM is sum of FEI1 and FEI2.

[0048] The VIE screener method is similar to the full test in all aspects of test including hardware, initial procedure, and measurements, except that it only includes the measurement of FEI1 and omits the additional aging of the oil and FEI2 measurement. Table 2 Example 1 Comparative Comparative Comparative Exam le 1 Exam le 2 Exam le 3 Table 2 - Continued Comparative Comparative Comparative Example 4 Example 5 Example 6

[0049] It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments of the invention. For example, the functions described above and implemented for operating are for illustration purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of this application. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

CLAIMS 1. A method for preserving fuel economy properties of lubricating oil composition, the method comprising providing a lubricating oil composition that includes: at least one base oil; and a mixture of esters, wherein the mixture includes monoglycerides, diglycerides, and triglycerides; and wherein the mixture of esters includes 40% to 55% C12esters and 10% to 25% C14esters, and 5% to 20% C16esters.

2. The method of claim 1, wherein the mixture of esters is present in 0.01 wt.% to 1.0 wt.% based on total weight of the lubricating oil composition.

3. The method of claim 1, wherein the C12ester is derived from lauric acid.

4. The method of claim 1, wherein C14ester is derived from myristic acid.

5. The method of claim 1, wherein the C16ester is derived from palmitic acid or palmitoleic acid.

6. The method of claim 1, wherein mixture of esters further includes C8ester, C10ester, or C18 ester.

7. The method of claim 6, wherein the C8 ester is derived from caprylic acid.

8. The method of claim 6, wherein the C10ester is derived from capric acid.

9. The method of claim 6, wherein the C18 ester is derived from oleic acid.

10. The method of claim 1, wherein the mixture of esters includes 20-55 wt.% of monoglycerides.

11. The method of claim 1, wherein the mixture of esters includes 20-40 wt.% of diglycerides.

12. The use of mixture of esters to preserve fuel economy in a lubricating oil composition, wherein the lubricating oil composition includes: at least one base oil; and a mixture of esters, wherein the mixture includes monoglycerides, diglycerides, and triglycerides; and wherein the mixture of esters includes 40% to 55% C12 esters and 10% to 25% C14 esters, and 5% to 20% C16esters.

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