Marine lubricant composition

Abstract

The marine engine lubricating oil composition has (a) a viscosity of 4.0 mm at 100°C 2 / s~8.0mm 2 The marine lubricating oil composition comprises (a) at least 40 wt. % of a lubricating oil having a kinematic viscosity of less than 1 / s; and (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons. The marine lubricating oil composition has a TBN of less than 70 mg KOH / g. The marine lubricating oil composition is a monograde lubricating oil composition that meets the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricating oils.

Description

[Technical Field]

[0001] The present disclosure relates to lubricating oil compositions, and more particularly to the use of light neutral base stocks and polyisobutylene thickeners in marine lubricating oil compositions. [Background technology]

[0002] This section is intended to introduce the reader to various aspects of technology that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. As such, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] Marine internal combustion engines can be broadly classified as low-, medium-, or high-speed engines. Low-speed engines are unique in size and operation. These engines are quite large and typically operate in the range of approximately 60 to 200 revolutions per minute (rpm). Low-speed engines operate on a two-stroke cycle and are typically direct-coupled, self-reversing engines in a "crosshead" configuration, where a divider and one or more stuffing boxes separate the power cylinder from the crankcase to prevent combustion products from entering the crankcase and mixing with the crankcase oil. Marine two-stroke cylinder lubricants must meet performance requirements to keep up with the demanding operating conditions of more modern, larger-bore engines operating at significantly fluctuating power, load, and cylinder liner temperatures. Complete separation of the crankcase from the combustion zone has led those skilled in the art to lubricate the combustion chamber and crankcase with different lubricants, referred to as cylinder lubricants and system oils, respectively. Marine cylinder lubricants and system oils are subject to unique requirements.

[0004] In two-stroke crosshead engines, cylinder oil is injected separately into each cylinder through a lubrication system positioned around the cylinder liner, lubricating the cylinders in a total-loss manner. Cylinder lubricants are not recirculated; they are burned along with the fuel. Cylinder lubricants must provide a strong film between the cylinder liner and piston rings to adequately lubricate the cylinder walls and prevent scuffing, be thermally stable to prevent deposits from forming on the hot surfaces of the piston and piston rings, and be able to neutralize sulfur-based, acidic combustion products. In contrast to cylinder lubricants, system oils are not exposed to the combustion chamber where fuel is burned and are formulated to last as long as possible to maximize the oil's lifespan.

[0005] System oil lubricates the crankshaft and crosshead of two-stroke engines. It lubricates the main bearings, crosshead bearings, gears, and camshafts, cools the piston undercrown, and protects the crankcase from corrosion. System oils must be able to prevent corrosion of the bearing shell metal and prevent rust in the crankcase when entrained water is present. System oils must also provide adequate fluid lubrication to the bearings and have a sufficient anti-wear system to provide wear protection for the bearings and gears under extreme pressure conditions. In contrast to cylinder lubricants, system oils are not exposed to the combustion chamber where fuel is burned and are formulated to last as long as possible to maximize oil life. Therefore, the primary performance characteristics of system oils relate to wear protection, oxidation stability, viscosity growth control, and deposit performance.

[0006] Unlike two-stroke crosshead engines, medium-speed engines typically operate within a range of approximately 250 to 1100 rpm and operate on a four-stroke cycle. These engines are typically trunk piston engines. Unlike crosshead engines, trunk piston engines use a single lubricant to lubricate all areas of the engine. Therefore, trunk piston engine oils have unique requirements compared to marine cylinder lubricants. Key lubricant performance parameters for operating trunk piston engines include piston cooling gallery and piston ring pack deposit control, oxidation and viscosity growth control, demulsification performance, and sludge control. When operating on marine residual fuel, these performance parameters are affected almost exclusively by asphaltene contamination from the marine residual fuel.

[0007] Recent health and environmental concerns have led to regulations mandating the use of lower-sulfur fuels for marine engine operation. As a result, manufacturers now design marine engines to use a variety of fuels, from carbon-based gaseous fuels (e.g., natural gas, biogas, landfill gas, wood gas, methane, propane, butane, ethylene, etc.), non-carbon-based gaseous fuels (e.g., ammonia, hydrogen), liquid ammonia, liquefied petroleum gas (LPG), alcohol-based fuels (e.g., methanol, ethanol), dimethyl ether, and high-quality distillate fuels to lower-quality medium or heavy fuels, such as marine residual fuels, which generally have high sulfur and asphaltene contents. When operating on non-residual fuels, the fuel contains much lower sulfur levels, with less of the asphaltenes present in the fuel. When lower-sulfur fuels are burned, fewer acids are formed in the combustion chamber.

[0008] One of the key characteristics of lubricants that contribute to the protection of marine engines is the "thickness" of the lubricant film, or viscosity. Because marine internal combustion engines operate at low speeds and high loads, the industry requires high viscosity lubricants, typically high-viscosity monograde lubricants (i.e., those exhibiting little or no viscosity index improving properties) with SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 viscosity grades. Because hydrocracking reduces the viscosity of base oils, marine oils cannot usually be formulated solely with hydrocracked base oils. To achieve adequate oil film thickness, conventional marine formulations typically include a majority amount of heavy neutral base stock and / or high-viscosity bright stock in marine lubricants. Bright stock is a highly refined and dewaxed high-viscosity base oil produced from residual stock or bottoms.

[0009] However, relying on bright stock is not always desirable because of the presence of oxidatively unstable aromatics. Additionally, bright stock availability is declining, and as a result, large volume uses, such as for marine engines, require alternative solutions to impart the desired viscosity to the lubricant. Considering the increasing severity of changes associated with modern marine engine design changes, changing regulations regarding fuel quality, along with declining bright stock capacity, there is a continuing need for improved marine lubricant formulation technology that improves performance while achieving the high viscosity required for marine lubricants. Summary of the Invention

[0010] A summary of certain embodiments disclosed herein is provided below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these particular embodiments, and that these aspects are not intended to limit the scope of the disclosure. Indeed, the disclosure may encompass a variety of aspects that may not be set forth below.

[0011] In general, in one aspect, the disclosure provides a method for producing a viscoelastic polymer having: (a) a viscosity of 4.0 mm at 100° C.; 2 / s~8.0mm 2 The marine engine lubricating oil composition comprises at least 40 wt. % of a lubricating oil having a kinematic viscosity of less than 1 / s and (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons. The marine lubricating oil composition is a monograde lubricating oil composition having a TBN of less than 70 mg KOH / g and meeting the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricants.

[0012] In another aspect, the disclosure relates to a method of thickening a lubricating oil composition in a marine internal combustion engine, the method comprising adding to the engine a lubricating oil composition having (a) a viscosity of 4.0 mmHg at 100°C or greater; 2 / s~8.0mm 2 and (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons. The marine lubricating oil composition is a monograde lubricating oil composition having a TBN of less than 70 mg KOH / g and meeting the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricating oils.

[0013] In a further aspect, the present disclosure relates to a method of controlling deposit formation in an internal combustion engine, the method comprising operating the internal combustion engine with a lubricating oil composition, the lubricating oil composition having (a) a viscosity of 4.0 mm at 100°C; 2 / s~8.0mm 2 and (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons. The marine lubricating oil composition is a monograde lubricating oil composition having a TBN of less than 70 mg KOH / g and meeting the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricating oils. DETAILED DESCRIPTION OF THE INVENTION

[0014] definition In this specification, the following words and expressions, if used, have the meanings ascribed to them.

[0015] "Major amount" means greater than 40 wt% of the composition.

[0016] "Minor amount" means less than 40 wt% of the composition.

[0017] "Marine residual fuel" refers to a material that can be burned in a large marine engine, having a carbon residue (based on the total weight of the fuel) of at least 2.5 wt% (e.g., at least 5 wt%, or at least 8 wt%) as defined by International Organization for Standardization (ISO) 10370, and a viscosity at 50°C greater than 14.0 cSt, e.g., marine residual fuel as defined in International Organization for Standardization standard ISO 8217:2005, "Spec for petroleum products -- Fuels (Class F) -- Marine fuels," the contents of which are incorporated herein by reference in their entireties.

[0018] "Residual fuel" means fuel that meets the specifications for residual marine fuels set forth in the ISO 8217:2010 international standard. "Low-sulphur residual fuel" means fuel that, in addition to meeting the specifications for residual marine fuels set forth in the ISO 8217:2010 standard, has no more than about 1.5 wt% sulphur, and in some cases no more than about 0.5 wt% sulphur, by weight of the total fuel.

[0019] "Distillate fuel" means a fuel that meets the specifications for distillate marine fuels as set forth in the ISO 8217:2010 International Standard. "Low sulfur distillate fuel" means a fuel that, in addition to meeting the specifications for distillate marine fuels as set forth in the ISO 8217:2010 International Standard, has not more than about 0.1 wt. % sulfur, and in some cases not more than about 0.005 wt. % sulfur, based on the total weight of the fuel.

[0020] "Low sulfur fuel" means about 1.5 wt% or less, in some cases about 1.0 wt% or less, in some cases 0.5 wt% or less, and in some cases 0.1 wt% or less sulfur, based on the total weight of the fuel.

[0021] A "high sulfur fuel" is a fuel having more than 1.5 wt% sulfur based on the total weight of the fuel.

[0022] The term "on an active matter basis" refers to additive materials that are neither diluent oils nor solvents.

[0023] As used in the present specification and claims, "alpha olefin" refers to an olefin having a carbon-carbon double bond between the first and second carbon atoms of the longest continuous carbon atom chain. The term "alpha olefin" includes linear and branched alpha olefins unless otherwise specified. In the case of branched alpha olefins, the branching can be at the 2-position (vinylidene) and / or the 3-position or higher relative to the olefinic double bond. The term "vinylidene" whenever used in the present specification and claims refers to an alpha olefin having a branch at the 2-position relative to the olefinic double bond. Alpha olefins are almost always mixtures of isomers, and often mixtures of compounds having a range of carbon numbers. Low molecular weight alpha olefins, such as C6, C8, C 10 , C 12 and C 14 Alpha olefins are almost exclusively 1-olefins. Higher molecular weight olefin cuts, e.g., C 16 -C 18 , or C 20 -C 24 Increasingly, the double bond is isomerized to an internal or vinylidene position.

[0024] "Normal alpha olefin" (NAO) refers to a linear aliphatic monoolefin having a carbon-carbon double bond between the first and second carbon atoms. Note that "normal alpha olefin" is not synonymous with "linear alpha olefin" because the term "linear alpha olefin" can include linear olefinic compounds having a double bond between the first and second carbon atoms.

[0025] "Isomerized olefin" or "isomerized normal alpha olefin" refers to an olefin obtained by isomerizing an olefin. Generally, an isomerized olefin has a double bond in a different position than the starting olefin from which it is derived, and may also have different properties.

[0026] "Isomerization level (I)" refers to the isomerization level measured by NMR. The isomerization level of olefins was determined by hydrogen-1 (H) NMR. NMR spectra were obtained in chloroform-d at 400 MHz on a Bruker Ultrashield Plus 400 using TopSpin 3.2 spectrum processing software. The isomerization level represents the relative amount of methyl groups (-CH) (chemical shifts 0.30-1.01 ppm) attached to methylene backbone groups (-CH-) (chemical shifts 1.01-1.38 ppm) and is defined by the equation (I) = m / (m + n), where m is the NMR integral of the methyl groups with chemical shifts 0.30 ± 0.03-1.01 ± 0.03 ppm, and n is the NMR integral of the methylene groups with chemical shifts 1.01 ± 0.03-1.38 ± 0.10 ppm.

[0027] The term "Total Base Number" or "TBN" or "BN" refers to the level of alkalinity in an oil sample according to ASTM Standard No. D2896 or an equivalent procedure, which represents the ability of a composition to continue to neutralize corrosive acids. The test measures the change in electrical conductivity, and the results are expressed as mgKOH / g (the equivalent number of milligrams of KOH required to neutralize one gram of product). Thus, a high TBN reflects a more overbased product and, consequently, a larger base reserve to neutralize acids. It should be understood that when TBN values ​​are referred to herein, they are expressed in units of mgKOH / g.

[0028] "Overbased" is used to describe metal detergents in which the ratio of the number of equivalents of metal moieties to the number of equivalents of acid moieties is greater than one.

[0029] "Soap" means a neutral detergent compound containing approximately a stoichiometric amount of metal to effect neutralization of the acid groups or groups present in the organic acid used to make the detergent.

[0030] "Metal" refers to an alkali metal, an alkaline earth metal, or a mixture thereof. When an alkali metal is used, the alkali metal is lithium, sodium, or potassium. When an alkaline earth metal is used, the alkaline earth metal may be selected from the group consisting of calcium, barium, magnesium, and strontium. Calcium and magnesium are preferred.

[0031] "Weight percent" (wt%) means the percentage of the listed component(s), compound(s), or substituent(s) that contributes to the total weight of the entire composition, unless expressly stated otherwise. All reported percentages are weight % on an active ingredient basis (i.e., without regard to carrier or diluent oil) unless otherwise stated. The diluent oil for a lubricating oil additive can be any suitable base oil (e.g., Group I base oil, Group II base oil, Group III base oil, Group IV base oil, Group V base oil, or mixtures thereof). The weight percentage representing the combination of raw materials and carrier or diluent oil is referred to as the "as received" weight percentage.

[0032] The term "sulfated ash content" refers to the amount of metal-containing additives (e.g., calcium, magnesium, molybdenum, zinc) in a lubricating oil composition, and is typically measured according to ASTM D874, which is incorporated herein by reference.

[0033] lubricating oil composition Surprisingly, it has been found that substituting (e.g., completely or partially substituting) heavy neutral base stock and bright stock in marine lubricants with a combination of lighter neutral base stock and polyisobutylene thickener results in marine lubricating oil compositions with improved resistance to deposit formation and oxidation stability in engines operating under a variety of load conditions, including high load conditions, while achieving adequate lubricating oil viscosity.

[0034] The lubricating oil composition of the present disclosure is, in certain embodiments, a marine engine lubricant. In such embodiments, the lubricating oil composition has (a) a viscosity of 4.0 mmHg at 100°C. 2 / s~8.0mm 2and (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons, wherein the lubricating oil composition is a monograde lubricating oil composition that meets the January 2015 revised SAE J300 requirements for SAE 20, 30, 40, 50, or 60 monograde lubricants and has a TBN of less than 70 mg KOH / g as determined by ASTM D2896. The kinematic viscosity of the lubricating oil viscosity may correspond to the viscosity of a light neutral base stock.

[0035] The lubricating oil composition may be a monograde lubricating oil composition that meets the January 2015 revised SAE J300 requirements for 20, 30, 40, 50, or 60 monograde engine oils. SAE 20 oils have a viscosity of 6.9 to <9.3 mm at 100°C. 2 SAE30 oil has a kinematic viscosity of 9.3 to <12.5 mm / s at 100°C. 2 SAE40 oil has a kinematic viscosity of 12.5 to <16.3 mm / s at 100°C. 2 SAE50 oil has a kinematic viscosity of 16.3 to <21.9 mm / s at 100°C. 2 SAE60 oil has a kinematic viscosity of 21.9 to <26.1 mm / s at 100°C. 2 / s kinematic viscosity.

[0036] In some embodiments, the lubricating oil composition is suitable for use as a marine cylinder lubricant (MCL). The marine cylinder lubricants of the present disclosure are formulated to SAE 40, SAE 50, or SAE 60 monograde specifications to form a sufficiently high viscosity lubricant film on the cylinder liner wall at high temperatures.

[0037] In addition to providing a sufficient degree of lubrication, one of the primary functions of marine cylinder lubricants is to neutralize the sulfur-based acidic components of combusted sulfur-containing fuels. This neutralization has typically been achieved by including basic species, such as overbased metal detergents. An oil's neutralization capacity is characterized by its basicity and measured by its total base number (TBN). Typically, sulfur-containing fuels used to power marine engines create the need for marine cylinder lubricants with high detergency and neutralization capacity, even when the oil is exposed to heat or other loads for only short periods of time. On the other hand, low-sulfur fuels may not require as much neutralization capacity as sulfur-containing fuels.

[0038] To allow for sufficient neutralization and cleaning power while maintaining relatively low deposit levels, the marine cylinder lubricants of the present disclosure have a TBN of less than 70 mgKOH / g. By way of example, the TBN may be less than 70 mgKOH / g to 2 mgKOH / g, or less than 70 mgKOH / g to 5 mgKOH / g, or less than 70 mgKOH / g to 10 mgKOH / g, less than 70 mgKOH / g to 15 mgKOH / g, less than 70 mgKOH / g to 20 mgKOH / g, 60 mgKOH / g to 2 mgKOH / g, 60 mgKOH / g to 5 mgKOH / g, 60 mgKOH / g to 60 mgKOH / g, or 60 mgKOH / g to 10 mgKOH / g. The TBN may range from 10 mgKOH / g to 10 mgKOH / g, 60 mgKOH / g to 15 mgKOH / g, 60 mgKOH / g to 20 mgKOH / g, 50 mgKOH / g to 2 mgKOH / g, 50 mgKOH / g to 5 mgKOH / g, 50 mgKOH / g to 10 mgKOH / g, 50 mgKOH / g to 15 mgKOH / g, or 50 mgKOH / g to 20 mgKOH / g. By way of further example, the TBN may range from less than 40 mgKOH / g to 2 mgKOH / g, or less than 40 mgKOH / g to 5 mgKOH / g, or less than 40 mgKOH / g to 10 mgKOH / g, less than 40 mgKOH / g to 15 mgKOH / g, or less than 40 mgKOH / g to 20 mgKOH / g. In certain embodiments, the TBN ranges from 40 mg KOH / g to 15 mg KOH / g.

[0039] In some embodiments, the lubricating oil compositions of this invention are suitable for use as marine trunk piston engine oils (TPEOs). Marine TPEO lubricants of this disclosure are manufactured to SAE 30 or SAE 40 monograde specifications. Such marine TPEO lubricants have a TBN ranging from greater than 15 mgKOH / g to 70 mgKOH / g (e.g., 30 mgKOH / g to 70 mgKOH / g, 35 mgKOH / g to 65 mgKOH / g, 40 mgKOH / g to 60 mgKOH / g).

[0040] In another embodiment, the lubricating oil composition of the present invention is suitable for use as a system oil (SO). Marine SO lubricants of the present disclosure are manufactured to SAE 20 and SAE 30 monograde specifications. Such marine SO lubricants have a TBN in the range of 2 mgKOH / g to 20 mgKOH / g (e.g., 5-20, 5-15, 5-12, 7-20, 7-15, 7-12, 8-20, 8-15, or 8-12 mgKOH / g).

[0041] In certain embodiments, the lubricating oil compositions of this disclosure have a sulfated ash content of at least 1.50 wt% as determined by ASTM D 874. For example, the lubricating oil compositions of this disclosure may have a sulfated ash level of 1.5 to 27 wt% as determined by ASTM D 874. By way of further example, the lubricating oil compositions of this disclosure may have a sulfated ash content of 2.0 to 25.0 wt%, 2.5 to 25.0 wt%, 3.0 to 25.0 wt%, or 5.0 to 25.0 wt%, as determined by ASTM D 874.

[0042] Lubricant viscosity The lubricating oil compositions of this disclosure have at least 40 wt% of a lubricating oil viscosity, e.g., at least 50 wt% (e.g., at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%), based on the total weight of the composition. For example, the lubricating oil compositions of this disclosure may contain 40 wt% to 95 wt%, 50 wt% to 90 wt%, or 55 wt% to 85 wt% of a lubricating oil viscosity. A lubricating oil of that viscosity may also be referred to as a base oil.

[0043] According to certain embodiments of the present disclosure, the lubricating oil viscosity is a kinematic viscosity at 100°C of 4.0 mm 2 / s~8.0mm 2 For example, the kinematic viscosity of the lubricating oil at 100°C is 4.0 mm / s or less. 2 / s~7.5mm 2 / s, or 4.5 mm 2 / s~7.5mm 2 / s, or 5.0 mm 2 / s~7.5mm 2 / s.

[0044] The lubricating oil viscosity of this disclosure may contain only one base oil component or a mixture of two or more base oil components to provide the above kinematic viscosity. The lubricating oil viscosity may be selected from any of Groups I to V of base oils specified in the American Petroleum Institute (API) Base Oil Interchangeability Specification (API 1509). The five base oil groups are summarized in Table 1 below. [Table 1]

[0045] Groups I-III are mineral oil process stocks. Group IV base oils contain true synthetic molecular species produced by the polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may contain diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and / or polyphenyl ethers, but may also be naturally occurring oils such as vegetable oils. It should be noted that although Group III base oils are derived from mineral oils, the severe processing these fluids undergo makes their physical properties more similar to those of some true synthetic oils, such as PAOs. Therefore, oils derived from Group III base oils are sometimes referred to in the industry as synthetic fluids.

[0046] The base oil used in the disclosed lubricating oil compositions can be mineral oil, animal oil, vegetable oil, synthetic oil, partially synthetic oil, bio-based oil, or mixtures thereof. Suitable oils can be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined and re-refined oils, and mixtures thereof.

[0047] Unrefined oils are derived from natural, inorganic, or synthetic sources without or little further purification treatment. Refined oils are similar to unrefined oils except that they have been treated with one or more purification steps, which may result in the improvement of one or more properties. Examples of suitable purification techniques include solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Oils refined to edible quality may or may not be useful. Edible oils are sometimes also referred to as white oils. In some embodiments, the lubricating oil composition does not contain edible oils or white oils.

[0048] Re-refined oils are also known as reclaimed or reprocessed oils. These oils are obtained using the same or similar processes as refined oils. Often, these oils are further processed by techniques aimed at removing spent additives and oil breakdown products.

[0049] Mineral oils may include liquid petroleum-based oils and solvent- or acid-treated inorganic lubricating oils of the paraffinic, naphthenic, or mixed paraffinic and naphthenic types. Such oils may be partially or fully hydrogenated, if desired. Oils derived from coal or shale are also useful.

[0050] Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomerized, or copolymerized olefins (e.g., polybutylene, polypropylene, propylene / isobutylene copolymers); poly(1-hexene), poly(1-octene), trimers of 1-decene, such as poly(1-decene), which are often referred to as alpha-olefins, as well as mixtures thereof; alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di-(2-ethylhexyl)benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers, and alkylated diphenyl sulfides, as well as their derivatives, analogs, and homologs, or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

[0051] Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decanephosphonic acid), or polymeric tetrahydrofurans. Synthetic oils can be produced by the Fischer-Tropsch reaction and are typically hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oils can be prepared by the Fischer-Tropsch gas-to-liquid synthesis procedure, similar to other gas-to-liquid oils.

[0052] Base oils for use in the formulated lubricants useful in this disclosure can be any of a variety of oils corresponding to API Group I, Group II, Group III, Group IV, and Group V oils, and mixtures thereof. In one embodiment, the base oil is a Group II base oil or a blend of two or more different base oils. In another 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 light overhead fractions from a vacuum distillation column, such as any of the light neutral, medium neutral, and heavy neutral feed base oils.

[0053] Base oils may also include residual feedstock base oils or bottoms fractions, such as bright stock. Bright stock is a high viscosity base oil traditionally produced from residual feedstock or bottoms oils and has been highly refined and dewaxed. Bright stock has a kinematic viscosity of 180 mmHg at 40°C. 2 / s or more (e.g., 250 mm 2 / s or more, in some cases 500-1100 mm 2 / s range). In certain embodiments, the lubricating oil composition is bright stock free.

[0054] thickener According to this embodiment, a thickener can be added to a lubricating oil composition to increase its viscosity to obtain a finished lubricating oil composition having a desired viscosity grade. Surprisingly, it has been discovered that replacing heavy neutral base stock and bright stock with a combination of lighter neutral base stock and a polyisobutylene (PIB) thickener in marine lubricants results in lubricating oil compositions with improved resistance to deposit formation and oxidation stability in engines operating under high load conditions, while achieving adequate lubricating oil viscosity.

[0055] The PIB thickener may be present in the lubricating oil composition in an amount of 0.1 to 50 wt% (e.g., 0.5 to 50 wt%, 1 to 50 wt%, 1 to 40 wt%, 2 to 40 wt%, 3 to 40 wt%, 2 to 35 wt% or 4 to 35 wt%, 1 to 35 wt%, 2 to 30 wt%, 3 to 30 wt%, 5 to 30 wt%, 0.5 to 25 wt%, 1 to 25 wt%, 1 to 20 wt%, 2 to 15 wt% or 4 to 15 wt%) based on the total weight of the composition. PIB is generally a viscous, oil-miscible liquid having a number average molecular weight of 400-6000 Daltons (eg, 500-5000 Daltons, 1000-5000 Daltons, 1200-4000 Daltons, 1000-2500 Daltons, 2000-2500 Daltons).

[0056] Polyisobutylene thickener has a viscosity of 50-50,000mm at 100°C. 2 / sec, e.g. 630~2,500mm2 By way of further example, the PIB thickener may have a kinematic viscosity in the range of 2,000 to 6,000 mm / sec at 100°C. 2 / sec, or 2,000 to 5,000 mm 2 / sec, or 3,000 to 4,500 mm 2 Polybutylene, specifically polyisobutylene or poly-n-butylene, can be prepared, for example, by polymerization of C4 refinery streams.

[0057] Other performance additives The lubricating oil compositions of this disclosure may contain one or more performance additives that can impart or improve any desirable property of the lubricating oil composition. Any additive known to a person skilled in the art may be used in the lubricating oil compositions disclosed herein. Some suitable additives are described in R.M. Mortier et al., "Chemistry and Technology of Lubricants," 3rd Edition, Springer (2010) and L.R. Rudnik, "Lubricant Additives: Chemistry and Applications," Second Edition, CRC Press (2009).

[0058] Generally, the concentration of each of the additives in the lubricating oil composition, when used, can range from 0.001 to 10 wt % (e.g., 0.01 to 5 wt %, or 0.05 to 2.5 wt %) of the lubricating oil composition. Including diluent oil, each of the additives in the lubricating oil composition can range from 0.5 to 45 wt % (e.g., 1.0 to 45 wt %, 5.0 to 40 wt %, 10 to 35 wt %, 20 to 32 wt %, or 25 to 30 wt %) of the lubricating oil composition. Furthermore, the total amount of additives in the lubricating oil composition can range from 0.001 to 20 wt % (e.g., 0.01 to 15 wt %, or 0.1 to 10 wt %) of the lubricating oil composition. The total amount of additives in the lubricating oil composition, including diluent oil, can be in the range of 0.5 to 78 wt % (e.g., 1.0 to 78 wt %, 5.0 to 78 wt %, 10 to 78 wt %, 20 to 78 wt %, 30 to 78 wt %, or 45 to 78 wt %) of the lubricating oil composition.

[0059] By way of example, the lubricating oil compositions may contain one or more lubricant performance additives including detergents, dispersants, antiwear agents, antioxidants, friction modifiers, corrosion inhibitors, rust inhibitors, demulsifiers, foam inhibitors, viscosity modifiers, pour point depressants, nonionic surfactants, thickeners, etc., some of which are described in more detail below.

[0060] Detergent The lubricating oil compositions of the present disclosure may contain one or more detergents. Detergents are additives that reduce the formation of piston deposits in engines, such as high-temperature varnish and lacquer deposits. Detergents usually have acid-neutralizing properties and are able to keep finely divided solids in suspension. Most detergents are metal salts of acidic organic compounds.

[0061] 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 contain a polar head with a long hydrophobic tail. The polar head comprises a metal salt of an acidic organic compound.

[0062] In the art, detergents are generally considered to be neutral or overbased. Detergents containing substantially stoichiometric amounts of metal salts are usually described as standard or neutral detergents. In embodiments where a large amount of metal base is incorporated into the detergent by reacting excess metal compound (e.g., oxide or hydroxide) with an acid gas (e.g., carbon dioxide), the detergent is considered to be overbased.

[0063] Overbased metal detergents are typically produced by carbonating (with CO) a mixture of a hydrocarbon, a detergent acid (e.g., a sulfonic or carboxylic acid), a metal oxide or hydroxide (e.g., calcium oxide or hydroxide), and a promoter, such as xylene, methanol, and / or water. For example, to prepare overbased calcium sulfonate in carbonation, calcium oxide or hydroxide reacts with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with excess CaO or Ca(OH) to form the sulfonate salt.

[0064] Overbased detergents may be further characterized as low overbased, medium overbased, or high overbased. A low overbased detergent may be, for example, an overbased salt having a TBN of less than 100. In one embodiment, the TBN of the low overbased salt may be from about 5 to about 80. In another embodiment, the TBN of the low overbased salt may be from about 10 to about 80. In yet another embodiment, the TBN of the low overbased salt may be from about 10 to about 50.

[0065] The medium overbased detergent may be, for example, an overbased salt having a TBN of from about 100 to about 250. In one embodiment, the TBN of the medium overbased salt may be from about 100 to about 200. In another embodiment, the TBN of the medium overbased salt may be from about 125 to about 175.

[0066] High overbased detergents can be, for example, overbased salts having a TBN of greater than 250. In one embodiment, the TBN of the high overbased salts can be from about 250 to about 800.

[0067] Compounds that can be used in detergents include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates and naphthenates, and other oil-soluble carboxylates of metals, especially alkali or alkaline earth metals such as barium, sodium, potassium, lithium, calcium, and magnesium. The most commonly used metals are calcium and magnesium, and mixtures of calcium and / or magnesium with sodium, both of which may be present in detergents used in lubricants.

[0068] In one embodiment, the detergent may be one or more alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids and is a carboxylate or salicylate. Suitable hydroxyaromatic compounds include mononuclear monohydroxy and polyhydroxyaromatic hydrocarbons having 1 to 4, preferably 1 to 3, hydroxyl groups.

[0069] Suitable hydroxyaromatic compounds include phenol, catechol, resorcinol, hydroquinone, pyrolol, cresol, etc. In certain embodiments, the preferred hydroxyaromatic compound is phenol.

[0070] The alkyl-substituted portion of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid can be derived from an alpha-olefin having 10 to 80 carbon atoms. The olefin can be linear, isomerized linear, branched, or partially branched linear. The olefin can be a mixture of linear olefins, isomerized linear olefins, branched olefins, partially branched linear olefins, or a mixture of any of the foregoing.

[0071] In some embodiments, the mixture of linear olefins is a mixture of normal alpha olefins selected from olefins having 10 to 40 carbon atoms per molecule. In one embodiment, the normal alpha olefins have been isomerized using at least one of a solid catalyst or a liquid catalyst.

[0072] In some embodiments, at least about 75 mol % (e.g., at least about 80 mol %, at least about 85 mol %, at least about 90 mol %, at least about 95 mol %, or at least about 99 mol %) of the alkyl groups contained in the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid, e.g., the alkyl groups of the alkaline earth metal salt of the alkyl-substituted hydroxybenzoic acid detergent, are C 20 In certain of these embodiments, the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid has at least 75 mole % C 20 ~C 28 In another embodiment, the alkali or alkaline earth metal salt of alkyl-substituted hydroxybenzoic acid is derived from an alkyl-substituted hydroxybenzoic acid in which the alkyl group is a residue of a normal alpha olefin. In another embodiment, at least about 50 mol% (e.g., at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 99 mol%) of the alkyl groups in the alkali or alkaline earth metal salt of alkyl-substituted hydroxybenzoic acid are C 20 ~C 24 It is an alkyl substituent.

[0073] In another embodiment, at least about 50 mol% (e.g., at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 99 mol%) of the alkyl groups of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid are C 14 ~C 18In another embodiment, the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid is an isomerized C 10 ~C 40 Normal alpha olefin, isomerized C 20 ~C 28 Normal alpha olefins, or preferably isomerized C 20 ~C 24 The alkyl group is derived from a normal alpha olefin. In one embodiment, the isomerized normal alpha olefin has an alpha olefin isomerization level of about 0.1 to about 0.4. In another embodiment, the alkyl group is derived from at least two alkyl phenols. The alkyl group attached to at least one of the at least two alkyl phenols is derived from an isomerized alpha olefin. The alkyl group attached to the other alkyl phenol can be derived from a branched or partially branched olefin, a highly isomerized olefin, or a mixture thereof.

[0074] The alkyl-substituted portion of the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid can be derived from cashew nut shell liquid (CNSL) or hydrodistilled CNSL. Distilled CNSL is a mixture of biodegradable meta-hydrocarbyl-substituted phenols, including cardanol, in which the hydrocarbyl groups are linear and unsaturated. Catalytic hydrogenation of distilled CNSL yields a mixture of meta-hydrocarbyl-substituted phenols, primarily enriched in 3-pentadecylphenol.

[0075] The alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids can be mixtures of ortho- and para-isomers. In one embodiment, the alkyl-substituted hydroxyaromatic carboxylic acids can contain 1 to 99% ortho-isomer and 99 to 1% para-isomer. In another embodiment, the alkyl-substituted hydroxyaromatic carboxylic acids can contain about 5 to 70% ortho-isomer and 95 to 30% para-isomer.

[0076] The alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid can be neutral or overbased. Generally, an overbased alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is one in which the TBN of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid has been increased by a process such as adding a base source (e.g., lime) and an overbasing acidic compound (e.g., carbon dioxide).

[0077] As noted, certain embodiments of lubricating oil formulations may use one or more sulfonate detergents, alone or in combination with other detergents. Sulfonates may be prepared from sulfonic acids obtainable by sulfonating alkyl-substituted aromatic hydrocarbons, such as those obtained by petroleum fractionation or the alkylation of aromatic hydrocarbons. Examples of alkyl-substituted aromatic hydrocarbons that may be sulfonated include those obtainable by alkylating benzene, toluene, xylene, naphthalene, diphenyl, or their halogen derivatives. Alkylation may be carried out in the presence of a catalyst and an alkylating agent having from 3 to more than 70 carbon atoms. Alkaryl sulfonates typically contain from 9 to 80 or more carbon atoms, preferably 16 to 60, more preferably 16 to 30, and most preferably 20 to 24 carbon atoms per alkyl-substituted aromatic moiety.

[0078] The oil-soluble sulfonates or alkaryl sulfonic acids may be neutralized with metal oxides, hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrosulfides, nitrates, borates, and ethers. The amount of metal compound is selected taking into account the desired TBN of the final product.

[0079] Metal salts of phenols and sulfurized phenols (e.g., phenates or sulfurized phenate detergents) are prepared by reacting phenols or sulfurized phenols with a suitable metal compound, such as an oxide or hydroxide. Sulfurized phenols can be prepared by reacting phenols with sulfur or sulfur-containing compounds, such as hydrogen sulfide, sulfur monohalides, or sulfur dihalides, to form a product that is usually a mixture of compounds in which two or more phenols are bridged by a sulfur-containing bridge. Further details regarding the general preparation of sulfurized phenates can be found, for example, in U.S. Pat. Nos. 2,680,096, 3,178,368, and 3,801,507, the contents of which are incorporated herein by reference.

[0080] The sulfur used to form the sulfide compounds can have any allotropic form of sulfur. The sulfur can be present either as molten sulfur, or as a solid (e.g., powder or particulate), or as a suspension of the solid in a compatible hydrocarbon liquid.

[0081] In some embodiments, it is desirable to use calcium hydroxide as the calcium base because it is easier to handle than, for example, calcium oxide, while still providing superior results. Other calcium bases, such as calcium alkoxides, may also be used.

[0082] Suitable alkyl phenols that can be used are those in which the alkyl substituent contains a sufficient number of carbon atoms so as to render the resulting alkyl phenate (e.g., overbased calcium sulfurized alkyl phenate) composition oil-soluble. Oil solubility can be provided by a single long chain alkyl substituent or by a combination of alkyl substituents. Typically, the alkyl phenol used is a mixture of different alkyl phenols, e.g., C 20 ~C 24The alkylphenol compound may be a mixture of alkylphenols. In one embodiment, a suitable alkylphenol compound will be derived from an isomerized normal alpha-olefin alkyl group having from about 10 to about 40 carbon atoms per molecule and an alpha-olefin isomerization level of from about 0.1 to about 0.4. In one embodiment, the isomerized normal alpha-olefin has from about 20 to about 24 carbon atoms. In one embodiment, a suitable alkylphenol compound will be derived from an alkyl group that is a branched olefinic propylene oligomer or mixture thereof having from about 9 to about 80 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 40 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 18 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 12 carbon atoms.

[0083] In one embodiment, suitable alkylphenolic compounds include distilled cashew nut shell liquid (CNSL) or hydrodistilled CNSL. Distilled CNSL is a mixture of biodegradable meta-hydrocarbyl-substituted phenols, including cardanol, in which the hydrocarbyl groups are linear and unsaturated. Catalytic hydrogenation of distilled CNSL yields a mixture of meta-hydrocarbyl-substituted phenols, primarily enriched in 3-pentadecylphenol.

[0084] The alkylphenol may be a para-alkylphenol, a meta-alkylphenol, or an ortho-alkylphenol. In certain embodiments, such as those requiring an overbased product, the alkylphenol preferably comprises predominantly para-alkylphenols, with no more than about 45 mole percent of the alkylphenols being ortho-alkylphenols; more preferably, no more than about 35 mole percent of the alkylphenols being ortho-alkylphenols. Alkyl-hydroxytoluenes or xylenes, and other alkylphenols having one or more alkyl substituents in addition to at least one long-chain alkyl substituent, may also be used. In the case of distilled cashew nut shell liquid, catalytic hydrogenation of the distilled CNSL results in a mixture of meta-hydrocarbyl-substituted phenols.

[0085] Generally, the selection of alkylphenols can be based on the properties desired in the marine engine lubricating oil composition, particularly TBN and oil solubility. Further information regarding the preparation of suitable alkylphenols can be found, for example, in U.S. Patent Nos. 5,024,773, 5,320,763, 5,318,710, and 5,320,762, each of which is incorporated herein by reference.

[0086] Typically, the amount of detergent can be from about 0.001 wt % to about 50 wt %, or from about 0.05 wt % to about 25 wt %, or from about 0.1 wt % to about 20 wt %, or from about 0.01 to 15 wt %, based on the total weight of the marine lubricating oil composition.

[0087] Detergents may also include mixed surfactant systems containing phenate and / or sulfonate components, such as "hybrid" or "complex" detergents formed by phenate / salicylate, sulfonate / phenate, sulfonate / salicylate, or sulfonate / phenate / salicylate, as described, for example, in U.S. Patent Nos. 6,429,178, 6,429,179, and 6,153,565. Detergents may also include methylene-bridged polyphenol compositions prepared by reacting phenol with formaldehyde or its reversible polymer, optionally sulfurizing the methylene-bridged intermediate, and then reacting the intermediate with an excess of a metal base to produce the methylene-bridged polyphenol phenate composition. In one embodiment, the methylene-bridged polyphenol phenate composition may be further reacted with an epoxide. In one embodiment, the methylene-bridged polyphenol phenate composition is not sulfurized.

[0088] The other detergents may be present in any suitable amount, for example, from 0.1 to 45 wt %, or from 0.5 to 30 wt % of the lubricating oil composition.

[0089] Dispersants The lubricating oil compositions of this disclosure may contain one or more dispersants. Oil-insoluble oxidation by-products are produced during engine operation. Dispersants help keep these by-products dissolved, thereby reducing their deposition on metal surfaces. Dispersants are often known as ashless dispersants because they contain no ash-forming metals prior to incorporation into a lubricating oil composition and typically do not contribute any ash when added to a lubricant. Ashless dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long-chain alkenyl succinimides. Examples of N-substituted long-chain alkenyl succinimides include polyisobutylene succinimides in which the number-average molecular weight of the polyisobutylene substituent ranges from 500 to 5000 daltons (e.g., 900 to 2500 daltons). Succinimide dispersants and their preparation are disclosed, for example, in U.S. Pat. Nos. 4,234,435 and 7,897,696. Succinimide dispersants are typically imides formed from polyamines, typically poly(ethyleneamines).

[0090] In some embodiments, the lubricant composition comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of 500 to 5000 daltons (e.g., 900 to 2500 daltons). The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0091] The dispersants may be post-treated by conventional methods by reaction with any of a variety of agents, including boron compounds (e.g., boric acid) and cyclic carbonates (e.g., ethylene carbonate).

[0092] Another class of dispersants includes Mannich bases, which are materials formed by condensing higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes, such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

[0093] Another class of dispersants includes high molecular weight esters prepared by the reaction of hydrocarbyl acylating agents with polyhydroxylated aliphatic alcohols such as glycerol, pentaerythritol, or sorbitol. Such materials are described in more detail in U.S. Pat. No. 3,381,022.

[0094] Another class of dispersants includes high molecular weight ester amides.

[0095] Dispersants may be present at 0.1 to 15 wt% of the lubricating oil composition. Anti-wear agents

[0096] Antiwear agents reduce friction and excessive wear and are usually based on compounds containing sulfur or phosphorus, or both. Of particular note are metal dihydrocarbyl dithiophosphates, where the metal can be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel, copper, or zinc. Zinc dihydrocarbyl dithiophosphates (ZDDPs) are oil-soluble salts of dihydrocarbyl dithiophosphates and have the formula: Zn[SP(S)(OR)(OR')]2 where R and R' can be the same or different hydrocarbyl radicals containing 1 to 18 (e.g., 2 to 12) carbon atoms. To obtain oil solubility, the total number of carbon atoms in the dithiophosphoric acid (i.e., R and R') is generally 5 or greater.

[0097] The antiwear agent may be present at 0.1 to 6 wt% of the lubricating oil composition.

[0098] antioxidants Antioxidants retard the oxidative breakdown of base oils during use, which can lead to deposits on metal surfaces, the presence of sludge, or increased viscosity of the lubricant.

[0099] Useful antioxidants include hindered phenols. Hindered phenol antioxidants often contain secondary butyl and / or tertiary butyl groups as steric hindrance groups. The phenol group may be further substituted with a hydrocarbyl group (typically linear or branched alkyl) and / or a bridging group connecting to a second aromatic group. Examples of hindered phenol antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-butylcresol, 2,4,6-tri-tert-butylphenol, 2,6-di-alkyl-phenolic propionic acid ester derivatives, and bisphenols, such as 4,4'-bis(2,6-di-tert-butylphenol) and 4,4'-methylene-bis(2,6-di-tert-butylphenol).

[0100] Sulfurized alkylphenols, and their alkali and alkaline earth metal salts, are also useful as antioxidants.

[0101] Non-phenolic antioxidants that can be used include aromatic amine antioxidants, such as diarylamines and alkylated diarylamines. Specific examples of aromatic amine antioxidants include N-phenyl-2-naphthylamine, 4,4'-dioctyldiphenylamine, butylated / octylated diphenylamine, nonylated diphenylamine, and octylated N-phenyl-2-naphthylamine.

[0102] The antioxidant may be present at 0.01 to 15.0 wt% of the lubricating oil composition.

[0103] friction modifiers A friction modifier is any material capable of changing the coefficient of friction of any lubricant or fluid-coated surface containing such material. Suitable friction modifiers may include fatty amines, esters such as borated glycerol esters, fatty phosphites, fatty amides, fatty epoxides, borated fatty epoxides, alkoxylated fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, or fatty imidazolines, as well as condensation products of carboxylic acids with polyalkylene-polyamines. As used herein, the term "fatty" with respect to friction modifiers means a carbon chain having 10 to 22 carbon atoms, typically a linear carbon chain. Molybdenum compounds are also known as friction modifiers. Friction modifiers may be present at 0.01 to 10.0 wt.% of the lubricating oil composition.

[0104] Rust inhibitor Rust inhibitors generally protect lubricated metal surfaces from chemical attack by water or other contaminants. Suitable rust inhibitors include nonionic rust inhibitors, including polyoxyalkylene agents (e.g., polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ethers, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene octylstearyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate, and polyethylene glycol monooleate); stearic acid and other fatty acids; dicarboxylic acids; metal soaps; fatty acid amine salts; metal salts of heavy sulfonic acids; partial carboxylic acid esters of polyhydric alcohols; phosphoric acid esters; (short-chain) alkenyl succinic acids, their partial esters, and nitrogen-containing derivatives thereof; and synthetic alkaryl sulfonates (e.g., metal dinonylnaphthalene sulfonates). Such additives may be present in an amount of 0.01 to 5 wt % of the lubricating oil composition.

[0105] Demulsifier Demulsifiers promote oil-water separation in lubricating oil compositions exposed to water or steam. Suitable demulsifiers include trialkyl phosphates and various polymers and copolymers of ethylene glycol, ethylene oxide, propylene oxide, or mixtures thereof. Such additives may be present at 0.01 to 5 wt % of the lubricating oil composition.

[0106] Foam suppressor Foam suppressors retard the formation of stable foam. Silicones and organic polymers are typical foam suppressors. For example, polysiloxanes, such as silicone oil or polydimethylsiloxane, provide foam suppression. Additional foam suppressors include copolymers of ethyl acrylate, 2-ethylhexyl acrylate, and optionally vinyl acetate. Such additives may be present at 0.001 to 1 wt % of the lubricating oil composition.

[0107] Viscosity modifier Viscosity modifiers provide lubricants with high and low temperature operability. These additives impart shear stability at elevated temperatures and acceptable viscosity at low temperatures. Suitable viscosity modifiers may include polyolefins, olefin copolymers (OCPs), ethylene / propylene copolymers, polyisobutene, hydrogenated styrene-isoprene polymers, styrene / maleic acid ester copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, alpha olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, and hydrogenated alkenylaryl conjugated diene copolymers. Such additives may be present at 0.1 to 15 wt % of the lubricating oil composition.

[0108] Pour Point Depressants Pour point depressants lower the minimum temperature at which a fluid will flow or can be poured. Examples of suitable pour point depressants include polymethacrylates, polyacrylates, polyacrylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl carboxylate polymers, and terpolymers of dialkyl fumarates, vinyl esters of fatty acids, and allyl vinyl ethers. Such additives may be present at 0.01 to 1.0 wt % of the lubricating oil composition.

[0109] Nonionic surfactants Nonionic surfactants, such as alkylphenols, can improve asphaltene handling during engine operation. Examples of such materials include alkylphenols having alkyl substituents from linear or branched alkyl groups having 9 to 30 carbon atoms. Other examples include alkylbenzenols, alkylnaphthols, and aldehyde condensates of alkylphenols, where the aldehyde is formaldehyde such that the condensate is a methylene-bridged alkylphenol. Such additives may be present at 0.1 to 20 wt % of the lubricating oil composition.

[0110] marker The lubricating oil compositions of the present invention may contain dye or marker components, e.g., tracers, which are particularly suitable for marking lubricants to protect the integrity of the brand, prevent misidentification, and aid in leak identification. The most useful types of markers or dyes are those that can be easily extracted, measured, and / or identified from the marked fluid. Many additives and tracers that have been proposed for use or are currently in use to mark or tag lubricants include colorants and fluorescent dyes (e.g., diazo dyes, anthraquinone dyes, phthalein dyes, etc.), radioactive materials, metal compounds or complexes (e.g., metal organic compounds, metal salts, metal oxides, metal coordination complexes, etc.), and various specific compounds that react in combination with selected agents to produce brightly colored derivatives.

[0111] Examples of markers include materials selected from the group consisting of barium sulfate, bismuth trioxide, iodine, iodide, titanium oxide, zirconium oxide, gold, platinum, silver, tantalum, niobium, stainless steel, and combinations thereof. Materials such as certain metal soaps, fatty acid metal soaps, metal carboxylates, or known metal desiccants supplied as solutions containing metals such as cobalt, lead, magnesium, titanium, zirconium, manganese, rhodium, platinum, aluminum, manganese, calcium, cerium, copper, nickel, vanadium, barium, tungsten, vanadium, and zinc, as well as mixtures thereof, are also useful as lubricant markers. Examples of zirconium-containing materials may include zirconium carboxylates, such as zirconium 2-ethylhexanoate, zirconium octoate, and zirconium salicylate materials.

[0112] Use of the lubricating oil composition The lubricant compositions may be useful as cylinder lubricants, trunk piston engine oils or system oils for compression ignition internal combustion engines, including marine engines and the like.

[0113] The internal combustion engine may be a two-stroke or a four-stroke engine.

[0114] In one embodiment, the internal combustion engine is a marine engine. In certain embodiments, the marine engine may be a medium-speed four-stroke compression ignition engine having a speed of 250-1100 rpm, or a low-speed crosshead two-stroke compression ignition engine having a speed of 200 rpm or less (e.g., 60-200 rpm).

[0115] Marine engines may be lubricated with marine cylinder lubricants (e.g., generally in two-stroke engines), system oils (typically in two-stroke engines), or crankcase lubricants (typically in four-stroke engines).

[0116] The term "marine" does not limit the engine to those used on surface vessels; as understood in the art, it includes those for other industrial uses, such as for auxiliary power generation for main propulsion, and stationary land-based engines for generating electricity.

[0117] In some embodiments, the internal combustion engine may be fueled by residual fuel, marine residual fuel, low sulfur marine residual fuel, marine distillate fuel, low sulfur marine distillate fuel, or high sulfur fuel.

[0118] An internal combustion engine may also be powered by a "gaseous fuel", such as a methane-based fuel (e.g., natural gas), biogas, landfill gas, wood gas, gasified liquefied gas, gasified liquefied natural gas (LNG), or a non-carbon-based gaseous fuel (e.g., ammonia, hydrogen). [Example]

[0119] The following illustrative examples are intended to be non-limiting.

[0120] The following components were used in formulating the example marine lubricant compositions: Generally, the example marine lubricant compositions included a viscous lubricant (base oil component), a thickener, and an additive package.

[0121] The base oil components used in the formulation of the examples included:

[0122] XOM 150N: ExxonMobil CORE® 150N Group I lubricant, KV 5.1mm at 100°C 2 / s

[0123] XOM 600N: ExxonMobil CORE® 600N: Group I lubricant, KV 12.4mm at 100°C 2 / s

[0124] XOM 2500BS: ExxonMobil CORE® 2500BS: Group I lubricant, KV 30.6mm at 100°C 2 / s

[0125] RLOP 100R: Chevron 100R Group II lubricant, KV 4.4mm at 100°C 2 / s

[0126] RLOP 220R: Chevron 220 RLOP: Group II lubricant, KV 6.4mm at 100℃ 2 / s

[0127] RLOP 600R: Chevron 600R RLOP: Group II lubricant, KV 12.0mm at 100℃ 2 / s

[0128] PIB-1: 2300MW polyisobutylene

[0129] PIB-2: 1000MW polyisobutylene

[0130] The additive package used in the formulation of the examples included the following:

[0131] Additive package A: 420BN calcium sulfonate detergent at 1.0 wt% oil concentration (40.0 wt% diluent oil), 17BN calcium sulfonate detergent at 6.0 wt% oil concentration (50.0 wt% diluent oil), 95BN sulfurized calcium phenate detergent (derived from C20-C24 isomerized alpha olefins) at 9.0 wt% oil concentration (20 wt% diluent oil), polyisobutylene succinimide dispersant at 0.2 wt% oil concentration, 1.5 wt% antioxidants, 0.1 wt% foam suppressor, and 1.0 wt% diluent oil.

[0132] Additive package B: 260BN overbased sulfurized calcium phenate detergent (derived from C20 to C24 isomerized alpha olefins) at 3.0 wt% oil concentration (40 wt% diluent oil), 410BN overbased calcium carboxylate detergent (derived from C20 to C24 isomerized alpha olefins) at 0.3 wt% oil concentration (33.0 wt% diluent oil), 180BN overbased calcium carboxylate detergent (derived from C20 to C24 isomerized normal alpha olefins) at 2.9 wt% oil concentration (20 wt% diluent oil), polyisobutylene succinimide dispersant at 3.5 wt% oil concentration, 1.5 wt% antioxidants, 0.1 wt% foam suppressor, and 0.4 wt% diluent oil.

[0133] Additive package C: 410BN overbased calcium carboxylate detergent (derived from C20 to C24 isomerized alpha olefins) at 7.5 wt% oil concentration (33.0 wt% diluent oil), 180BN overbased calcium carboxylate detergent (derived from C20 to C24 isomerized alpha olefins) at 5.2 wt% oil concentration (20.0 wt% diluent oil), 0.7 wt% secondary zinc dithiophosphate, and 0.1 wt% foam suppressor.

[0134] Additive package D: 95BN calcium sulfide phenate detergent (derived from C20-C24 isomerized alpha olefins) at an oil concentration of 0.6 wt% (20.0 wt% diluent oil), 410BN overbased calcium carboxylate detergent (derived from C20-C24 isomerized alpha olefins) at an oil concentration of 1.1 wt% (33.0 wt% diluent oil), 0.6 wt% zinc primary dithiophosphate, 0.02 wt% foam suppressor, and 0.1 wt% diluent oil.

[0135] Additive Package E: 420BN calcium sulfonate detergent at 8.0 wt% oil concentration (40.0 wt% diluent oil), 17BN calcium sulfonate detergent at 2.0 wt% oil concentration (50.0 wt% diluent oil), 95BN sulfurized calcium phenate detergent (derived from C20 to C24 isomerized alpha olefins) at 5.0 wt% oil concentration (20 wt% diluent oil), polyisobutylene succinimide dispersant at 0.2 wt% oil concentration, antioxidants at 1.5 wt%, foam suppressor at 0.1 wt%, and diluent oil at 0.9 wt%.

[0136] Additive package F: 420BN calcium sulfonate detergent at 7.8 wt% oil concentration (40.0 wt% diluent oil), 17BN calcium sulfonate detergent at 2.0 wt% oil concentration (50.0 wt% diluent oil), 260BN sulfurized calcium phenate detergent (propylene tetramer derived) at 1.0 wt% oil concentration (30 wt% diluent oil), 116BN sulfurized calcium phenate detergent (propylene tetramer derived) at 3.0 wt% oil concentration (40.0 wt% diluent oil), polyisobutylene succinimide dispersant at 0.2 wt% oil concentration, 1.5 wt% antioxidants, 0.1 wt% foam suppressor, and 0.9 wt% diluent oil.

[0137] Additive package G: 420BN calcium sulfonate detergent at 6.9 wt% oil concentration (40.0 wt% diluent oil), 17BN calcium sulfonate detergent at 6.0 wt% oil concentration (50.0 wt% diluent oil), 95BN sulfurized calcium phenate detergent (derived from C20-C24 isomerized alpha olefins) at 9.0 wt% oil concentration (20 wt% diluent oil), polyisobutylene succinimide dispersant at 0.2 wt% oil concentration, 1.5 wt% antioxidants, 0.1 wt% foam suppressor, and 1.3 wt% diluent oil.

[0138] The following examples were evaluated for their degree of oxidative stability using the tests described below, and the results for each example are shown in Tables 2-6.

[0139] Test Method DSC oxidation test The thin film oxidation stability of the test oils was evaluated using a DSC test according to ASTM D-6186. During the test, the heat flow into and out of the test oil in the sample cup is compared to a reference cup. The oxidation onset temperature is the temperature at which oxidation of the test oil begins. The oxidation induction time is the time at which oxidation of the test oil begins. The longer the oxidation induction time, the better the performance. The oxidation reaction is exothermic and is evident by heat flow. The oxidation induction time is calculated to evaluate the thin film oxidation stability of the test oil.

[0140] The DSC oxidation test can also be used to evaluate the deposit control performance of a lubricant, since oxidative species generated during engine operation have a tendency to form deposits. Thus, higher oxidation stability can usually be correlated with reduced deposit formation.

[0141] MIP-48 (Modified Institute of Petroleum 48) Test The MIP-48 test consists of a thermal section and an oxidation section. During both sections of the test, the test sample is heated. During the thermal section of the test, nitrogen is flowed through the heated oil sample for 24 hours. In parallel, during the oxidation section of the test, air is flowed through the heated oil sample for 24 hours. The samples are cooled, and the viscosities of both samples are determined. The viscosity increase of the test oil caused by oxidation is determined and corrected for thermal effects. The oxidation-induced viscosity increase of each marine lubricating oil composition was calculated by subtracting the kinematic viscosity of the nitrogen-blown sample at 200°C from the kinematic viscosity of the air-blown sample at 200°C and dividing the result by the kinematic viscosity of the nitrogen-blown sample at 200°C. This is done to correct for possible evaporation effects or any other thermal effects during the test, thereby focusing on the effects of oxidation. This correction may result in negative values. Test oils exhibiting better stability to oxidation-induced viscosity increase will result in a lower absolute % value.

[0142] result Example 1 and Comparative Example A Example 1 and Comparative Example A were formulated into marine cylinder lubricant compositions with a 15BN, SAE 50 viscosity grade (18.5 cSt KV at 100°C) containing 18.8 wt% of Additive Package A. Comparative Example A was formulated using a combination of heavy mineral oil, Chevron RLOP600R, and XOM2500BS bright stock to achieve the appropriate lubricant viscosity. Example 1 contained a combination of light distillate mineral oil, Chevron RLOP220R, and polyisobutylene thickener to achieve the appropriate lubricant viscosity for the finished lubricant. Each lubricant was evaluated for high-temperature oxidation stability using the DSC oxidation test. The results for each of the examples are shown in Table 2 below. [Table 2]

[0143] The results in Table 2 show that the marine cylinder lubricant composition containing a combination of light distillate mineral oil and polyisobutylene thickener exhibited surprisingly better oxidation performance than Comparative Example A. This is evident from the longer oxidation induction time of Example 1 compared to Comparative Example A. Furthermore, Example 1 was formulated to achieve an SAE 50 viscosity grade without using more heavy neutral base stock and bright stock than conventionally used in the finished lubricant composition.

[0144] Examples 2 and 3 and Comparative Examples B and C Examples 2 and 3 and Comparative Examples B and C were formulated into marine cylinder lubricant compositions with a 40BN, SAE 50 viscosity grade (18.5 cSt KV at 100°C) containing additive package E and additive package F (wt % in the table below). The finished lubricants of Comparative Examples B and C were formulated using a combination of heavy mineral oil and bright stock to achieve the appropriate lubricant viscosity. The finished lubricants of Examples 2 and 3 contained a combination of light distillate mineral oil, Chevron RLOP220R, and polyisobutylene thickener to achieve the appropriate lubricant viscosity. Each lubricant was evaluated for oxidation stability using the DSC oxidation test. The results for each example are shown in Table 3 below. [Table 3]

[0145] As shown in Table 3, the marine cylinder lubricant compositions containing a combination of light neutral base stock and polyisobutylene thickener exhibited surprisingly better oxidation performance, as evidenced by higher oxidation induction times, than Comparative Examples B and C. Additionally, Examples 2 and 3 were formulated to achieve an SAE 50 viscosity grade without the use of heavy lubricating oil and bright stock in the finished lubricant compositions.

[0146] Examples 4 and 5 and Comparative Examples D and E Examples 4 and 5 and Comparative Examples D and E were formulated into marine trunk piston engine lubricating oil (TPEO) compositions of 15BN and 40BN, SAE 40 viscosity grade (14.0 cSt KV at 100°C). Example 4 and Comparative Example D, which contained 11.7 wt.% of additive package B, were formulated with 15BN TPEO. Example 5 and Comparative Example E, which contained 13.5 wt.% of additive package C, were formulated with 40BN TPEO. The finished lubricants of Comparative Examples D and E were formulated using a combination of heavy mineral oil and bright stock to achieve the appropriate lubricating oil viscosity. The finished lubricants of Examples 4 and 5 contained a combination of light distillate mineral oil, Chevron RLOP220R, and polyisobutylene thickener to achieve the appropriate lubricating oil viscosity. Each lubricant was evaluated for oxidation stability using the DSC oxidation test. The results for each example are shown in Table 4 below. [Table 4]

[0147] As shown in Table 4, the marine trunk piston engine lubricating oil compositions containing a combination of light neutral base stock and polyisobutylene thickener exhibited surprisingly better oxidation performance, as evidenced by the greater oxidation induction times, than Comparative Examples B and C. Additionally, Examples 2 and 3 were formulated to achieve an SAE 50 viscosity grade without the use of heavy lubricating oil and bright stock in the finished lubricating oil compositions.

[0148] Example 6 and Comparative Example F Example 6 and Comparative Example F were formulated into marine system lubricant compositions with a 5BN, SAE 30 viscosity grade (11.5 cSt KV at 100°C) containing 2.4 wt% additive package D. Comparative Example F was formulated using a heavy mineral oil, Chevron RLOP600R, to achieve the appropriate lubricant viscosity. Example 6 contained a combination of a light distillate mineral oil, Chevron RLOP220R, and polyisobutylene thickener to achieve the appropriate lubricant viscosity for the finished lubricant. Each lubricant was evaluated for high-temperature oxidation stability using the DSC oxidation test. The results for each example are shown in Table 5 below. [Table 5]

[0149] The results in Table 5 show that the marine system lubricant composition containing a combination of light distillate mineral oil and polyisobutylene thickener exhibited surprisingly better oxidation performance than Comparative Example F. This is evidenced by the longer oxidation induction time of Example 6 compared to Comparative Example F. Furthermore, Example 6 was formulated to achieve an SAE 30 viscosity grade without using more heavy neutral base stock and bright stock than conventionally used in the finished lubricant composition.

[0150] Examples 7 and 8 and Comparative Example G Examples 7 and 8 and Comparative Example G were formulated into marine cylinder lubricant compositions with a 40BN, SAE 50 viscosity grade (18.5 cSt KV at 100°C) containing additive package G (wt % in the table below). The finished lubricant of Comparative Example G was formulated using a combination of heavy mineral oil and bright stock to achieve the appropriate lubricant viscosity. The finished lubricants of Examples 7 and 8 each contained a combination of light distillate mineral oil, XOM Core 150N, and polyisobutylene thickener to achieve the appropriate lubricant viscosity. Each lubricant was evaluated for oxidation stability using the DSC oxidation test. The results for each example are shown in Table 6 below. [Table 6]

[0151] As shown in Table 6, the marine cylinder lubricant compositions containing the combination of light neutral base stock XOM150N and polyisobutylene thickener exhibited surprisingly better oxidation performance, as evidenced by the greater oxidation induction time, than Comparative Example G. Additionally, Examples 7 and 8 were formulated to achieve an SAE 50 viscosity grade without the use of conventional heavy lubricant and bright stock in the finished lubricant compositions.

[0152] It should be understood that the specific embodiments described above are shown by way of example, and that these embodiments may be susceptible to various modifications and alternative forms and may be used in any suitable combination. Furthermore, it should be understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

Claims

1. 1. A marine engine lubricating oil composition comprising: (a) Viscosity is 4.0 mm at 100°C ２ / s ~ 8.0 mm ２ at least 40 wt. % of a lubricating oil having a kinematic viscosity of less than 1 / 2 s; (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons; Including, The marine lubricating oil composition has a TBN of less than 70 mg KOH / g, and further, the marine lubricating oil composition is a monograde lubricating oil composition that meets the requirements of SAE J300, revised January 2015, for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricants.

2. 10. The composition of claim 1, wherein the one or more polyisobutylene thickeners have a number average molecular weight of 1000 to 2500 Daltons.

3. The one or more polyisobutylene thickeners have a viscosity of 630 to 2500 mm at 100° C. ２ 10. The composition of claim 1 having a kinematic viscosity in the range of 1 / sec.

4. 10. The composition of claim 1, wherein the one or more polyisobutylene thickeners are present in the lubricating oil composition at 4 to 40 wt %.

5. 10. The composition of claim 1, wherein the one or more polyisobutylene thickeners are the only viscosity modifiers present in the lubricating oil composition.

6. 10. The composition of claim 1, wherein the lubricating oil composition is bright stock-free.

7. 10. The composition of claim 1, wherein the lubricating oil composition has a sulfated ash content of 1.5 wt% or greater.

8. 10. The composition of claim 1, wherein the lubricating oil composition has a TBN of from 10 mg KOH / g to less than 70 mg KOH / g.

9. 10. The composition of claim 1, wherein the lubricating oil composition comprises a polyisobutylene succinimide dispersant.

10. 10. The composition of claim 1, wherein the lubricating oil composition is a marine cylinder lubricant having a TBN of greater than 20 mg KOH / g and less than 70 mg KOH / g.

11. 10. The composition of claim 1, wherein the lubricating oil composition is a marine trunk piston engine oil having a TBN of greater than 15 mg KOH / g to 70 mg KOH / g.

12. 10. The composition of claim 1, wherein the lubricating oil composition is a marine system oil having a TBN of greater than 2 mg KOH / g to 20 mg KOH / g.

13. 1. A method of thickening a lubricating oil composition in a marine internal combustion engine, the method comprising adding to the engine a lubricating oil composition comprising: (a) Viscosity is 4.0 mm at 100°C ２ / s ~ 8.0 mm ２ at least 40 wt. % of a lubricating oil having a kinematic viscosity of less than 1 / 2 s; (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons; Including, The marine lubricating oil composition has a TBN of less than 70 mg KOH / g, and further, the marine lubricating oil composition is a monograde lubricating oil composition that meets the specifications of the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricants.

14. 14. The method of claim 13, wherein the one or more polyisobutylene thickeners are present in the lubricating oil composition at 4 to 40 wt %.

15. 14. The method of claim 13, wherein the one or more polyisobutylene thickeners are the only viscosity modifiers present in the lubricating oil composition.

16. 14. The method of claim 13, wherein the lubricating oil composition is bright stock-free.

17. 14. The method of claim 13, wherein the lubricating oil composition has a sulfated ash content of 1.5 wt% or greater.

18. The method of claim 13, wherein the lubricating oil composition has a TBN of from 10 mg KOH / g to less than 70 mg KOH / g.

19. 14. The method of claim 13, wherein the lubricating oil composition comprises a polyisobutylene succinimide dispersant.

20. 1. A method for controlling deposit formation in an internal combustion engine, the method comprising operating the internal combustion engine with a lubricating oil composition comprising: (a) Viscosity is 4.0 mm at 100°C ２ / s ~ 8.0 mm ２ at least 40 wt. % of a lubricating oil having a kinematic viscosity of less than 1 / 2 s; (b) one or more polyisobutylene thickeners having a number average molecular weight of 400 to 6,000 Daltons; Including, The marine lubricating oil composition has a TBN of less than 70 mg KOH / g, and further, the marine lubricating oil composition is a monograde lubricating oil composition that meets the specifications of the January 2015 revised SAE J300 requirements for SAE 20, SAE 30, SAE 40, SAE 50, or SAE 60 monograde lubricants.

21. 21. The method of claim 20, wherein the one or more polyisobutylene thickeners are present in the lubricating oil composition at 4 to 40 wt %.

22. 21. The method of claim 20, wherein the one or more polyisobutylene thickeners are the only viscosity modifiers present in the lubricating oil composition.

23. 21. The method of claim 20, wherein the lubricating oil composition does not contain bright stock.

24. 21. The method of claim 20, wherein the lubricating oil composition has a sulfated ash content of 1.5 wt.% or greater.

25. The method of claim 20, wherein the lubricating oil composition has a TBN of from 10 mg KOH / g to less than 70 mg KOH / g.

26. 21. The method of claim 20, wherein the lubricating oil composition comprises a polyisobutylene succinimide dispersant.

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