CN105950262B

CN105950262B - Lubricating oil composition with enhanced piston cleanliness

Info

Publication number: CN105950262B
Application number: CN201610255066.4A
Authority: CN
Inventors: R·霍根杜恩; B·B·霍根杜恩
Original assignee: Chevron Oronite Technology BV
Current assignee: Chevron Oronite Technology BV
Priority date: 2015-02-13
Filing date: 2016-02-06
Publication date: 2020-12-18
Anticipated expiration: 2036-02-06
Also published as: CN105950262A; EP3056556B1; SG10201601063QA; EP3056556A1; CA2919739A1

Abstract

A low and medium sulfur, phosphorous and sulfated ash (low and medium "SAPS") lubricating oil composition is disclosed for providing enhanced piston cleanliness to an internal combustion engine comprising at least one Mannich reaction product prepared by condensation of a polyisobutyl-substituted hydroxyaromatic compound, an aldehyde, an amino acid or ester derivative thereof, and an alkali metal base, wherein the polyisobutyl group is derived from polyisobutylene containing at least 70 wt.% of a methylvinylidene isomer and has a number average molecular weight of 400 to 2,500.

Description

Lubricating oil composition with enhanced piston cleanliness

Background

1. Field of the invention

The present invention relates generally to low and medium sulfur, phosphorus and Sulfated Ash (SAPS) lubricating oil compositions for enhancing piston cleanliness in internal combustion engines.

2. Description of the Prior Art

When selecting lubricating oils, the viscosity grade of the engine oil is a key feature. The lubricating oil is typically selected based on the climate temperature to which the engine is exposed and the temperature and shear conditions under which the engine is operating. Thus, the oil must be of sufficiently low viscosity at ambient temperature to provide adequate lubrication at engine cold start and be able to maintain sufficient viscosity to lubricate the engine at full engine load operation.

The society of automotive Engineers classification system SAE J300 defines an engine oil grade viscosity specification. Single stage is designated SAE20, 30, 40, 50 and 60 grades and is defined by a low shear rate kinematic viscosity range at 100 ℃ (ASTM D445) and a minimum high shear rate viscosity at 150 ℃ (e.g., ASTM D4683, CEC L-36-A-90 or ASTM D5481). Engine oils designated SAE0W to 25W are classified according to their low temperature cranking viscosity (ASTM D5293), low temperature pumping viscosity (ASTM4684) and minimum kinematic viscosity at 100 ℃.

The multi-stage lubricating oil operates over a wide temperature range. Typically, they are identified by two numbers, e.g., 5W-30 or 10W-30. The first number in the multi-step designation refers to the required safe start-up temperature (e.g., -20 ℃) viscosity requirement for multi-step oils as measured by a cold start simulator (CCS) at high shear rates (ASTM D5293). In general, lubricants with low CCS viscosities allow the engine to start more easily at lower temperatures and thus improve engine stability at those ambient temperatures.

The second number in the multi-step designation refers to the lubricant viscosity at normal operating temperature and is measured as kinematic viscosity (Kv) at 100 ℃ (ASTM D445). High temperature viscosity needs to encompass minimum and maximum kinematic viscosities at 100 ℃. Viscosity at high temperatures is needed to prevent engine wear if the lubricating oil is too thin during engine operation. However, the lubricating oil should not be excessively viscous, as excessive viscosity may result in unnecessary viscous drag and work to pump the lubricant, which in turn may increase fuel consumption. In general, the lower the Kv of the lubricant at 100 ℃, the higher the fraction of the lubricant obtained in the fuel economy test.

Thus, in order to meet the given multigrade oil designation, a particular multigrade oil must simultaneously meet stringent low and high temperature viscosity requirements, which are set by SAE specifications such as SAE J300.

Merely blending base stocks of different viscosity characteristics may not enable the formulation to meet the low and high temperature viscosity requirements of certain multigrade oils. The primary means of the formulation to achieve this goal is an additive, commonly referred to as a viscosity modifier or viscosity index (V.I.) improver. Typically, to achieve the target minimum high temperature viscosity, a large amount of viscosity modifier needs to be added. However, an increase in the amount of the viscosity modifier used results in an increased low-temperature lubricating viscosity. The increasing demand for formulated crankcase lubricants exhibiting improved performance in fuel economy testing is driving the industry to develop low viscosity grade engine lubricants such as SAE0W-20, 0W-30, 5W-20, and 5W-30.

Consistent with the requirements for low viscosity, high fuel economy lubricants, there is a continuing effort to reduce the amount of sulfated ash, phosphorus and sulfur in crankcase lubricants due to environmental factors and to ensure compatibility with pollution control devices (e.g., three-way catalytic converters and particulate traps) used in conjunction with modern engines. Particularly effective antioxidant-antiwear additives suitable for use in lubricant formulations are the metal salts of dialkyldithiophosphates, particularly zinc salts thereof, commonly referred to as ZDDP. While such additives provide excellent performance, ZDDP contributes to sulfating each of ash, phosphorus and sulfur for lubricants.

The catalytic converter typically comprises one or more oxidation catalysts, NO_XStorage catalyst and/or NH₃The catalyst is reduced. The catalysts contained herein typically comprise a combination of catalytic metals, such as platinum, and metal oxides. A catalytic converter is assembled in an exhaust system, such as an exhaust pipe of an automobile, to convert toxic gases into non-toxic gases. The use of catalytic converters is believed to be critical to mitigating global warming trends and combating other environmental hazards. However, as a result of exposure to particular elements or compounds, particularly phosphorus-containing compounds such as ZDDP, the catalyst may become poisoned and cause failure, if not useless.

Particulate traps are often incorporated into exhaust systems, particularly diesel engines, to prevent the release of soot particles or very fine condensed particles or aggregates thereof (i.e., "diesel soot") into the environment. Diesel soot is considered to be a carcinogen in addition to other elements polluting the air, water and environment. However, these traps can become clogged with metallic ash, which is a degradation product of metal-containing lubricating oil additives, including common ash-generating detergent additives.

In order to ensure long-term service life of aftertreatment devices, it is desirable to determine that lubricating oil additives have minimal negative impact on such devices. In this regard, OEMs often set different limits on the maximum sulfur, phosphorus and/or sulfated ash levels of "new service charge" and "first charge" lubricants. For example, when applied to internal combustion engines for light passenger vehicles, the sulfur content typically needs to be 0.30 wt% or less, the phosphorus content 0.08 wt% or less, and the sulfated ash content 0.8 wt% or less. However, when the lubricating composition is applied to a heavy duty internal combustion engine, the maximum sulfur, phosphorus and/or sulfated ash content may be different. For example, in those heavy duty engines, the maximum sulfated ash content may be as high as 1.6 wt%. Such lubricating oil compositions are also known as "SAPS Medium" (i.e., medium levels of sulfated ash, phosphorus, and sulfur). When the maximum sulfated ash is as high as 1.0 wt.%, the lubricating oil composition will be referred to as a "low SAPS" lubricating oil composition, for example for gasoline engines, and a "LEDL" (i.e., low emission diesel lubricant) oil composition, for diesel engines.

Different tests have been established and standardized to measure SAPS content in any particular lubricating oil composition. For example, in Europe, lubricants meeting ACEA gasoline and diesel engine low SAPS specifications, in particular, must pass the "CEC L-78-T-99" test, cycle alternately between idle and full load, after running a popular automotive turbocharged direct injection automotive diesel engine for extended periods of time, measuring cleanliness and piston ring sticking. Similar specifications and test standards of varying stringency can also be found in other countries and regions, such as japan, canada, and the united states.

However, meeting low SAPS environmental standards does not eliminate the need to provide adequate lubrication performance. Automotive spark ignition and diesel engines have valvetrain systems, including valves, cams and rockers, all of which require lubrication and avoid wear. In addition, engine oils must provide sufficient detergency to ensure cleanliness of the engine and to inhibit the formation of deposits, which are the products of unburned and incomplete combustion of hydrocarbon fuels and degradation of engine oils.

As noted above, the need to maintain the integrity of the catalytic converter has to result in the use of less phosphate and phosphorous-containing additives. However, due to the continuing need to neutralize oxidatively derived acids and polar oxidation residues suspended in lubricants, the use of detergents, typically metal sulfonate detergents, is often unavoidable. However, these detergents can lead to the formation of sulfated ash. The allowable ash content can be exceeded under most current environmental standards by using metal sulfate detergents far less than necessary to achieve adequate detergency performance. Reducing the level of detergent overbasing can reduce the level of ash produced, but it also reduces the acid neutralization capacity of the lubricant composition, potentially leading to acid corrosion of engine pistons and other parts.

The oil-soluble Mannich condensation products are suitable for use in internal combustion engine lubricating oils. These products generally act as dispersants to disperse sludge, varnishes and coatings and prevent the formation of deposits. In general, conventional oil-soluble Mannich condensation products are formed by the reaction of a polyisobutyl-substituted phenol with formaldehyde and an amine or polyamine. For example, number 7,964,543; 8,394,747, respectively; 8,455,681, respectively; 8,722,927 and 8,729,297 disclose that Mannich condensation products formed by combining, under reaction conditions, 0.01 to 10.0 wt.% of a polyisobutyl-substituted hydroxyaromatic compound in which the polyisobutyl group is derived from polyisobutylene containing at least 50 wt.% of the methylvinylidene isomer and has a number average molecular weight of about 400 to about 5000, an aldehyde, an amino acid or ester thereof, and an alkali metal base can be used in engine lubricating oil compositions. Each of these patents further disclose in the examples the addition of 1 weight percent of the Mannich condensation product to a fully synthesized (full formatted) SAE grade 5W-30 base oil, an SAE grade 5W-40 base oil and an SAE grade 10W-40 base oil.

Thus, there is a need to provide improved low and medium SAPS lubricating oil compositions that are SAE0W multigrade lubricants that can overcome poor fuel economy.

Summary of The Invention

According to an embodiment of the present invention, there is provided a lubricating oil composition comprising:

(a) greater than 65 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a kinematic viscosity (Kv) at 100 ℃ of from about 3.5 to about 4.5 centistokes (cSt);

(b) from about 3.0 wt% to about 10 wt%, based on the total weight of the lubricating oil composition, of at least one Mannich reaction product prepared by condensation of a polyisobutyl-substituted hydroxyaromatic compound, an aldehyde, an amino acid or ester derivative thereof, and an alkali metal base, wherein the polyisobutyl group is derived from polyisobutylene comprising at least about 70 wt% methylvinylidene isomer and has a number average molecular weight of from about 400 to about 2,500;

(c) at least one ashless dispersant different from component (b);

wherein the lubricating oil composition has a sulfur content of less than or equal to about 0.30 wt.%, a phosphorus content of less than or equal to about 0.09 wt.%, and a sulfated ash content of less than or equal to about 1.60 wt.%, as determined by ASTM D874, based on the total weight of the lubricating oil composition; and further wherein the lubricating oil composition is a multigrade lubricating oil composition meeting the specifications for a 0W-X multigrade engine oil requirement for SAE J300, revised 11 months 2007, where X is 20, 30, 40, 50, or 60.

According to a second embodiment of the present invention, there is provided a method for improving piston cleanliness of an internal combustion engine, the method comprising operating the internal combustion engine using a lubricating oil composition comprising:

(a) greater than 65 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt;

(c) at least one ashless dispersant different from component (b);

According to a third embodiment of the present invention, there is provided a use of a lubricating oil composition comprising:

(c) at least one ashless dispersant different from component (b);

wherein the lubricating oil composition has a sulfur content of less than or equal to about 0.30 wt.%, a phosphorus content of less than or equal to about 0.09 wt.%, and a sulfated ash content of less than or equal to about 1.60 wt.%, as determined by ASTM D874, based on the total weight of the lubricating oil composition; and further wherein the lubricating oil composition is a multigrade lubricating oil composition meeting the specifications for 0W-X multigrade engine oil requirements for SAE J300, revised 11 months 2007, where X is 20, 30, 40, 50, or 60, for improving piston cleanliness of an internal combustion engine.

The present invention is based upon the surprising discovery, among other things, that the combination of dispersants of the present invention can provide the enhanced piston cleanliness performance required in modern low and medium SAPS lubricants (i.e., SAE0W multigrade lubricants for internal combustion engines). By using the combination of dispersants of the present invention, low and medium SAPS lubricants (i.e., SAE0W multigrade lubricants) can be prepared that pass piston cleanliness and piston ring adhesion tests and thereby achieve improved fuel economy. Furthermore, it is believed that the combination of dispersants of the present invention may further provide seal compatibility in low and medium SAPS lubricants (i.e., SAE0W multigrade lubricants for internal combustion engines).

Detailed description of the preferred embodiments

Before discussing the present invention in more detail, the following terms will be defined:

definition of

As used herein, the following terms have the following meanings, unless explicitly indicated to the contrary:

the term "total number of bases" or "TBN" as used herein refers to the amount of bases in milligrams of KOH in a 1 gram sample. Thus, higher TBN numbers react more basic products and, therefore, greater alkalinity reserves. The TBN of the test specimens can be determined by ASTM test number D2896-11 published 5/15/2011 or any other equivalent procedure.

The term "metal" refers to an alkali metal, an alkaline earth metal, or mixtures thereof.

The term "alkaline earth metal" refers to calcium, barium, magnesium and strontium.

The term "alkali metal" refers to lithium, sodium, potassium, rubidium, and cesium.

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

The term "mannich condensation product" as used herein refers to a mixture of products obtained by the condensation reaction of a polyisobutyl-substituted hydroxyaromatic compound as described herein with an aldehyde and an amino acid to form a condensation product having the formula. The following formula is provided only as a few examples of certain Mannich condensation products that are believed to be the present invention and is not intended to exclude other possible Mannich condensation products that may be formed using the methods described herein.

R, R therein₁X and W are as defined herein.

The present invention relates to a lubricating oil composition comprising:

(c) at least one ashless dispersant different from component (b);

wherein the lubricating oil composition has a sulfur content of less than or equal to about 0.30 wt.%, a phosphorus content of less than or equal to about 0.09 wt.%, and a sulfated ash content of less than or equal to about 1.60 wt.%, based on the total weight of the lubricating oil composition; and further wherein the lubricating oil composition is a multigrade lubricating oil composition meeting the specifications for a 0W-X multigrade engine oil requirement for SAE J300, revised 11 months 2007, where X is 20, 30, 40, 50, or 60.

The lubricating oil composition of the present invention is more suitable from an environmental point of view than conventional internal combustion engine lubricating oils containing higher phosphorus, sulfur and sulphated ash contents. The lubricating oil composition of the present invention also promotes longer useful life of the catalytic converter and particulate trap while providing the desired piston cleanliness.

Generally, the sulfur content of the lubricating oil compositions of the present invention is less than or equal to about 0.30 wt.%, based on the total weight of the lubricating oil composition, e.g., a sulfur content of about 0.01 wt.% to about 0.30 wt.%. In one embodiment, the sulfur content of the lubricating oil composition of the present invention is less than or equal to about 0.20 wt.%, based on the total weight of the lubricating oil composition, e.g., a sulfur content of about 0.01 wt.% to about 0.20 wt.%. In one embodiment, the sulfur content of the lubricating oil composition of the present invention is less than or equal to about 0.10 wt.%, based on the total weight of the lubricating oil composition, e.g., a sulfur content of about 0.01 wt.% to about 0.10 wt.%.

In one embodiment, the amount of phosphorus in the lubricating oil composition of the present invention is less than or equal to about 0.09 wt.%, based on the total weight of the lubricating oil composition, for example, a phosphorus content of about 0.01 wt.% to about 0.09 wt.%. In one embodiment, the amount of phosphorus in the lubricating oil composition of the present invention is less than or equal to about 0.08 wt.%, based on the total weight of the lubricating oil composition, for example a phosphorus content of about 0.01 wt.% to about 0.08 wt.%. In one embodiment, the amount of phosphorus in the lubricating oil composition of the present invention is less than or equal to about 0.07 wt.%, based on the total weight of the lubricating oil composition, for example a phosphorus content of about 0.01 wt.% to about 0.07 wt.%. In one embodiment, the amount of phosphorus in the lubricating oil composition of the present invention is less than or equal to about 0.05 wt.%, based on the total weight of the lubricating oil composition, for example, a phosphorus content of about 0.01 wt.% to about 0.05 wt.%.

In one embodiment, the amount of sulfated ash produced by the lubricating oil composition of the present invention is less than or equal to about 1.60 wt.% as determined by ASTM D874, for example, a sulfated ash content of about 0.10 to about 1.60 wt.% as determined by ASTM D874. In one embodiment, the amount of sulfated ash produced by the lubricating oil composition of the invention is less than or equal to about 1.00 wt.% as determined by ASTM D874, for example an amount of sulfated ash of about 0.10 to about 1.00 wt.% as determined by ASTM D874. In one embodiment, the amount of sulfated ash produced by the lubricating oil composition of the invention is less than or equal to about 0.80 wt.% as determined by ASTM D874, for example an amount of sulfated ash of about 0.10 to about 0.80 wt.% as determined by ASTM D874. In one embodiment, the amount of sulfated ash produced by the lubricating oil composition of the present invention is less than or equal to about 0.60 wt.% as determined by ASTM D874, for example, a sulfated ash content of about 0.10 to about 0.60 wt.% as determined by ASTM D874.

The lubricating oil compositions of the present invention are fully synthetic, low or medium SAPS multigrade lubricating oil compositions, meeting the specification of SAE J300, revised 11 months 2007 for requirements for 0W-X multigrade engine oils, where X is 20, 30, 40, 50, or 60. In one embodiment, the lubricating oil composition of the present invention is a fully synthetic, low or medium SAPS SAE0W-20 multigrade lubricating oil composition. In one embodiment, the lubricating oil composition of the present invention is a fully synthetic, low or medium SAPS SAE 0W-30 multigrade lubricating oil composition. In one embodiment, the lubricating oil composition of the present invention is a fully synthetic, low or medium SAPS SAE 0W-40 multigrade lubricating oil composition. In one embodiment, the lubricating oil composition of the present invention is a fully synthetic, low to medium SAPS SAE 0W-50 multigrade lubricating oil composition. In one embodiment, the lubricating oil composition of the present invention is a fully synthetic, low or medium SAPS SAE 0W-60 multigrade lubricating oil composition.

Base oil component

Lubricating oil compositions of the present invention comprise greater than 65 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt. In practice, this means that the base oil component is selected from one or more natural oils, synthetic oils or mixtures thereof which meet the above-mentioned Kv at 100 ℃. In one embodiment, the lubricating oil composition of the present invention comprises at least about 70 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt. In one embodiment, the lubricating oil composition of the present invention comprises at least about 75 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt.

In one embodiment, the lubricating oil composition of the present invention comprises greater than 65 wt.% up to about 85 wt.%, based on the total weight of the composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt. In one embodiment, the lubricating oil composition of the present invention comprises from about 70 wt.% to about 85 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt. In one embodiment, the lubricating oil composition of the present invention comprises from about 75 wt.% to about 85 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from about 3.5 to about 4.5 cSt.

In general, the base oil component having a Kv of from about 3.5 to about 4.5cSt at 100 ℃ comprises at least one mineral oil base stock. In general, the at least one mineral oil base stock used in the base oil composition is selected from any natural mineral oil of API group I, II, III, IV, V or mixtures thereof used in crankcase lubricating oils for spark-ignition and compression-ignition engines. API principles define base stocks as lubricant components that can be prepared using a number of different methods.

Group I base oils typically relate to lubricating base oils derived from petroleum, having a saturates content of less than 90 wt% (determined according to ASTM D2007) and/or a total sulfur content of greater than 300ppm (determined according to ASTM D2622, ASTM D4294, ASTM D4297 or ASTM D3120), and a Viscosity Index (VI) of greater than or equal to 80 and less than 120 (determined according to ASTM D2270).

Group II base oils typically relate to lubricating base oils derived from petroleum, having a total sulfur content of equal to or less than 300 parts per million (ppm) (determined according to ASTM D2622, ASTM D4294, ASTM D4927 or ASTM D3120), a saturates content of equal to or greater than 90 wt% (determined according to ASTM D2007), and a Viscosity Index (VI) of 80 to 120 (determined according to ASTM D2270).

Group III base oils typically relate to lubricating base oils derived from petroleum, have less than 300ppm sulfur, greater than 90 wt% saturates, and a VI of 120 or greater. In one embodiment, the group III base stock comprises at least about 95 wt% saturated hydrocarbons. In another embodiment, the group III base stock comprises at least about 99 wt% saturated hydrocarbons. The term "major amount" as used herein refers to an amount greater than 50 wt%, alternatively greater than about 70 wt%, alternatively from about 80 to about 95 wt%, alternatively from about 85 to about 95 wt%, based on the total weight of the composition.

Group IV base oils are Polyalphaolefins (PAOs).

Group V base oils include all other base oils not included in groups I, II, III or IV.

In a preferred embodiment, the base oil group having a Kv of about 3.5 to about 4.5cSt at 100 ℃ is a group II or III base stock. In another preferred embodiment, the base oil group having a Kv of about 3.5 to about 4.5cSt at 100 ℃ is a group III base stock.

The lubricating oil composition may contain minor amounts of other base oil components. For example, the lubricating oil composition may include a minor amount of a base oil derived from a natural lubricating oil, a synthetic lubricating oil, or mixtures thereof. Suitable base oils include base stocks obtained by isomerization of synthetic and slack waxes, as well as hydrocracked base stocks produced by hydrocracking (rather than solvent extracting) the aromatic and polar components of the crude.

Suitable natural oils include mineral lubricating oils such as liquid petroleum oils, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic-naphthenic types, oils derived from coal or shale, animal oils, vegetable oils (e.g., rapeseed oils, castor oils, and lard oil), and the like.

Suitable synthetic lubricating oils include, but are not limited to, hydrocarbon oils and halo-substituted hydrocarbon oils, such as polymerized and interpolymerized hydrocarbons, e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, poly (1-hexenes), poly (1-octenes), poly (1-decenes), and the like, and mixtures thereof; alkylbenzenes such as dodecylbenzene, tetradecylbenzene, dinonylbenzene, di (2-ethylhexyl) benzene, and the like; polyphenyls such as biphenyls, terphenyls, alkylated polyphenyls, and the like; alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.

Other synthetic lubricating oils include, but are not limited to, oils prepared by polymerizing olefins of less than 5 carbon atoms, such as ethylene, propylene, butylenes, isobutene, pentene, and mixtures thereof. Methods for preparing such polymer oils are known to those skilled in the art.

Other synthetic hydrocarbon oils include liquid polymers of alpha-olefins having the correct viscosity. Particularly suitable synthetic hydrocarbon oils are C₆To C₁₂Hydrogenated liquid oligomers of alpha-olefins, such as 1-decene trimer.

Another class of synthetic lubricating oils includes, but is not limited to, alkylene oxide polymers, i.e., homopolymers, interpolymers, and derivatives thereof where the terminal hydroxyl groups are modified, for example, by esterification or etherification. Such oils are, for example, oils prepared by polymerization of ethylene oxide or propylene oxide, the alkyl and phenyl ethers of these polyoxyalkylene polymers (e.g., methyl polypropylene glycol ether having an average molecular weight of 1,000, polyethylene glycol diphenyl ether having a molecular weight of 500-1000, polypropylene glycol diethyl ether having a molecular weight of 1,000 to 1,500, etc.), or mono-and polycarboxylic esters thereof, such as acetates, mixed C₃-C₈Fatty acid esters, orC of tetraethyleneglycol₁₃A diester of an oxo acid.

Yet another class of synthetic lubricating oils includes, but is not limited to, the esters of dicarboxylic acids such as phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenyl malonic acids, and the like, with various alcohols such as butanol, hexanol, dodecanol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, and the like. 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, a complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid, and the like.

Esters suitable for use as synthetic oils also include, but are not limited to, those prepared from carboxylic acids having from about 5 to about 12 carbon atoms and alcohols such as methanol, ethanol, and the like, polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, and the like.

Silicon-based oils such as polyalkyl, polyaryl, polyalkoxy or polyaryloxy siloxane oils and silicate oils comprise another useful class of synthetic lubricating oils. Specific examples include, but are not limited to, tetraethyl silicate, tetraisopropyl silicate, tetra- (2-ethylhexyl) silicate, tetra- (4-methylhexyl) silicate, tetra (p-tert-butylphenyl) silicate, hexyl- (4-methyl-2-pentoxy) disiloxane, poly (methyl) siloxanes, poly (methylphenyl) siloxanes, and the like. Other suitable synthetic lubricating oils include, but are not limited to, liquid esters of phosphorus-containing acids such as tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphionic acid, and the like, polytetrahydrofuran, and the like.

The lubricating oil may be derived from unrefined, refined and re-refined oils, either natural, synthetic or mixtures of any two or more of the types described above. Unrefined oils are those obtained directly from a natural or synthetic source (e.g., coal, shale, or tar sands) without further refining or treatment. Examples of unrefined oils include, but are not limited to, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from distillation, or an ester oil obtained directly from an esterification process, each of which is used without further treatment. Refined oils are similar to unrefined oils except they are further treated in one or more purification steps to improve one or more properties. Such purification techniques are known to those skilled in the art and include, for example, solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, hydrotreating, dewaxing, and the like. Rerefined oils are obtained by treating used oils in processes similar to those used to obtain refined oils. Such rerefined oils are also known as reclaimed or reprocessed oils and are typically further processed by techniques directed to the removal of spent additives and oil breakdown products.

Lubricating oil base stocks derived from the hydroisomerization of wax may also be used, either alone or in combination with the aforesaid natural and/or synthetic base stocks. Such wax isomerate oils are produced by the hydroisomerization of natural or synthetic waxes, or mixtures thereof, over a hydroisomerization catalyst.

Natural waxes are typically slack waxes recovered by solvent dewaxing of mineral oils; synthetic waxes are typically waxes formed by fischer-tropsch synthesis.

Mannich reaction products

The lubricating oil composition of the present invention will further comprise from about 3.0 wt.% to about 10 wt.%, based on the total weight of the lubricating oil composition, of at least one Mannich reaction product prepared by condensation of a polyisobutyl-substituted hydroxyaromatic compound, an aldehyde, an amino acid or ester derivative thereof, and an alkali metal base, wherein the polyisobutyl group is derived from polyisobutylene comprising at least about 70 wt.% methylvinylidene isomer and has a number average molecular weight of from about 400 to about 2,500. In general, the predominant Mannich condensation product can be represented by the structure of formula I:

wherein each R is independently-CHR '-, R' is a branched or linear alkyl group having from 1 to about 10 carbon atoms, a cycloalkyl group having from about 3 to about 10 carbon atoms, an aryl group having from about 6 to about 10 carbon atoms, an alkylaryl group having from about 7 to about 20 carbon atoms, or an arylalkyl group having from about 7 to about 20 carbon atoms, R₁Is a polyisobutyl group derived from polyisobutylene containing at least about 70 wt% methylvinylidene isomer and having a number average molecular weight of from about 400 to about 2,500.

X is hydrogen, an alkali metal ion, or an alkyl group having 1 to about 6 carbon atoms;

w is- [ CHR "]-_mWherein each R' is independently H, an alkyl group having from 1 to about 15 carbon atoms, or a substituted alkyl group having from 1 to about 10 carbon atoms, and one or more substituents are selected from amino, amido, benzyl, carboxyl, hydroxyl, hydroxyphenyl, imidazolyl, imino, phenyl, sulfide, or mercapto; and m is an integer of 1 to 4.

Y is hydrogen, alkyl having 1 to about 10 carbon atoms, -CHR 'OH, wherein R' is as defined above, or

Wherein Y ' is-CHR ' OH, wherein R ' is as defined above; and R, X and W are as defined above;

z is hydroxy, a hydroxyphenyl group of the formula:

or

Wherein, R, R₁Y', X and W are as defined above,

and n is an integer from 0 to 20, with the proviso that when n ═ 0, Z must be:

r, R therein₁Y', X and W are as defined above.

In one embodiment, R₁The number average molecular weight of the polyisobutyl group is from about 500 to about 2,500. In one embodiment, R₁The number average molecular weight of the polyisobutyl group is from about 700 to about 1,500. In one embodiment, R₁The number average molecular weight of the polyisobutyl group is from about 700 to about 1,100. In one embodiment, R₁The polyisobutyl group is derived from polyisobutylene containing at least about 70 wt% methylvinylidene isomer. In one embodiment, R₁The polyisobutyl group is derived from polyisobutylene containing at least about 90 wt% methylvinylidene isomer.

In the compounds of formula I as above, X is an alkali metal ion, and most preferably a sodium or potassium ion. In another embodiment, in the compounds of formula I as above, X is an alkyl group selected from methyl or ethyl.

In one embodiment, R is CH₂，R₁Derived from polyisobutylene comprising at least about 70 wt% methylvinylidene isomer and having a number average molecular weight of about 700 to about 1,100, and W is CH₂X is sodium ion and n is 0 to 20.

The Mannich condensation products used in the lubricating oil compositions of the present invention may be prepared by combining under reaction conditions a polyisobutyl-substituted hydroxyaromatic compound, an aldehyde, an amino acid or ester derivative thereof, and an alkali metal base, wherein the number average molecular weight of the polyisobutyl group is from about 400 to about 2,500. In one embodiment, the Mannich condensation product is prepared by a Mannich condensation of:

(a) a polyisobutyl-substituted hydroxyaromatic compound having the formula:

wherein R is₁Is a polyisobutyl group derived from polyisobutylene containing at least about 70 wt% methylvinylidene isomer and having a number average molecular weight of from about 400 to about 2,500, R₂Is hydrogen or lower alkyl having 1 to about 10 carbon atoms, and R₃Is hydrogen or-OH;

(b) formaldehyde or an aldehyde having the formula:

wherein R' is a branched or linear alkyl group having from 1 to about 10 carbon atoms, a cycloalkyl group having from about 3 to about 10 carbon atoms, an aryl group having from about 6 to about 10 carbon atoms, an alkaryl group having from about 7 to about 20 carbon atoms, an aralkyl group having from about 7 to about 20 carbon atoms;

(c) an amino acid or ester derivative thereof having the formula:

wherein W is- [ CHR "]-_mWherein each R' is independently H, an alkyl group having from 1 to about 15 carbon atoms, or a substituted alkyl group having from 1 to about 10 carbon atoms, and one or more substituents are selected from amino, amido, benzyl, carboxyl, hydroxyl, hydroxyphenyl, imidazolyl, imino, phenyl, sulfide, or mercapto; and m is an integer from 1 to 4, and a is hydrogen or alkyl having from 1 to about 6 carbon atoms; and

(d) an alkali metal base.

Polyisobutyl-substituted hydroxyaromatic compounds

A variety of different polyisobutyl-substituted hydroxyaromatic compounds may be used in the preparation of the Mannich condensation products of the present invention. The key feature is polyisobutylThe substituents are sufficiently large to impart oil solubility to the final Mannich condensation product. In general, it is desirable that the number of carbon atoms in the polyisobutyl substituent used to permit oil solubility of the Mannich condensation product be equal to about C₂₀Either close or larger. This corresponds to a molecular weight of about 400 to about 2,500. Desirably, C on the phenol ring₂₀Or a larger alkyl substituent, is located para to the OH group on the phenol.

The polyisobutyl-substituted hydroxyaromatic compound is typically a polyisobutyl-substituted phenol in which the polyisobutyl moiety is derived from polyisobutylene containing at least about 70 weight percent methylvinylidene isomer, and more preferably, the polyisobutyl moiety is derived from polyisobutylene containing at least about 90 weight percent methylvinylidene isomer. The term "polyisobutyl or polyisobutyl substituent" as used herein relates to polyisobutyl substituents on hydroxy aromatic rings. The number average molecular weight of the polyisobutyl substituent is from about 400 to about 2,500. In one embodiment, the number average molecular weight of the polyisobutyl moiety is from about 450 to about 2,500. In one embodiment, the number average molecular weight of the polyisobutyl moiety is from about 700 to about 1,500. In one embodiment, the number average molecular weight of the polyisobutyl moiety is from about 700 to about 1,100.

In a preferred embodiment, the linkage of the polyisobutyl substituent to the hydroxy aromatic ring in the para position relative to the hydroxy moiety is at least about 60% of the total polyisobutyl-substituted phenol molecule. In one embodiment, the linkage of the polyisobutyl substituent to the hydroxy aromatic ring in the para position relative to the hydroxy moiety is at least about 80% of the total polyisobutyl-substituted phenol molecule. In a preferred embodiment, the polyisobutyl substituent is attached to the hydroxy aromatic ring in the para position relative to the hydroxy moiety on the phenol ring is at least about 90% of the total polyisobutyl-substituted phenol molecule.

Disubstituted phenols are likewise suitable starting materials for the Mannich condensation products of the present invention. Disubstituted phenols are suitable as long as they are substituted in such a way that an unsubstituted ortho position is present on the phenol ring. Examples of suitable disubstituted phenols are C₂₀Or larger polyisobutyl substituents and the like, or ortho-cresol derivatives substituted at the para-position.

In one embodiment, the polyisobutyl-substituted phenol has the formula:

wherein R is₁Is a polyisobutyl group derived from polyisobutylene containing at least about 70 wt% methylvinylidene isomer and having a number average molecular weight of from about 400 to about 2,500, and Y is hydrogen.

Suitable polyisobutenes can employ boron trifluoride (BF) as described in U.S. Pat. Nos. 4,152,499 and 4,605,808₃) Alkylation catalysts, the contents of which are incorporated herein by reference. Commercially available polyisobutenes having a high content of alkylvinylidene groups include those available from BASF

1000. 1300, and 2300.

The preferred polyisobutyl-substituted phenol for use in preparing the Mannich condensation products is a monosubstituted phenol in which the polyisobutyl substituent is attached to the phenol ring at the para position. However, other polyisobutyl-substituted phenols which can undergo Mannich condensation reactions can also be used to prepare Mannich condensation products according to the present invention.

Solvent(s)

Suitable solvents are, for example, hydrocarbon compounds such as heptane, benzene, toluene, chlorobenzene, aromatic solvents, neutral oils of lubricating viscosity, paraffins, and naphthenes

An Aromatic 100N neutral oil, a fatty acid,

150N neutral oil.

Typically, the alkyl substituent on the aromatic solvent has from about 3 to about 15 carbon atoms, and in one embodiment, the alkyl substituent on the aromatic solvent has from about 6 to about 12 carbon atoms.

Aldehydes

Suitable aldehydes for use in forming the Mannich condensation products include formaldehyde or an aldehyde having the formula

Wherein R' is a branched or linear alkyl group having from 1 to about 10 carbon atoms, a cycloalkyl group having from about 3 to about 10 carbon atoms, an aryl group having from about 6 to about 10 carbon atoms, an alkaryl group having from about 7 to about 20 carbon atoms, or an aralkyl group having from about 7 to about 20 carbon atoms.

Representative aldehydes include, but are not limited to, aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, and heptaldehyde aromatic aldehydes may also be used in the preparation of Mannich condensation products such as benzaldehyde and alkylbenzaldehydes such as p-tolualdehyde₂O and a trimer having the formula (CH)₂O)₃(trioxymethylene).

Examples of liquid formaldehyde are as follows:

monomer CH in Ether₂O.

Monomer CH in Water₂O, having the formula CH₂(H₂O)₂(methylene glycol) and HO (-CH)₂O)_n-H.

Monomer CH in methanol₂O, having the formulaOHCH₂OCH₃And CH₃O(-CH₂O)_n-H.

The formaldehyde solution is a commercially available aqueous solution and various alcoholic solutions, a suitable aqueous solution is a 37% to 50% solution, formalin is a 37% aqueous solution.

Amino acids

Suitable amino acids or ester derivatives thereof suitable for use in forming the Mannich condensation products include amino acids having the formula

Wherein W is- [ CHR "]-_mWherein each R' is independently H, an alkyl group having from 1 to about 15 carbon atoms, or a substituted alkyl group having from 1 to about 10 carbon atoms, and one or more substituents are selected from amino, amido, benzyl, carboxyl, hydroxyl, hydroxyphenyl, imidazolyl, imino, phenyl, sulfide, or mercapto; and m is an integer from 1 to 4, and A is hydrogen or an alkyl group having from 1 to about 6 carbon atoms.

In one embodiment, the amino acid is glycine.

The term "amino acid salt" as used herein relates to a salt of an amino acid having the formula

Where W is as defined above, and M is an alkali metal ion.

Some examples of suitable alpha-amino acids for preparing the Mannich condensation products are given in Table I below.

TABLE I

0.1 ionic strength

20 ℃ and 0.1 ionic strength

Alkali metal base

Suitable alkali metal bases for forming the Mannich condensation products include alkali metal hydroxides, alkali metal alkoxides, and the like. In one embodiment, the alkali metal base is an alkali metal hydroxide selected from sodium hydroxide, lithium hydroxide, or potassium hydroxide.

In one embodiment, the amino acid may be added in the form of an alkali metal ion salt. In one embodiment, the alkali metal ion is a sodium ion or a potassium ion. In a preferred embodiment, the alkali metal ion is sodium ion.

General procedure for the preparation of Mannich condensation products

The reaction to form the Mannich condensation product may be carried out batch-wise, or in a continuous or semi-continuous manner. The pressure of this reaction is usually atmospheric pressure, but the reaction may be carried out at subatmospheric or superatmospheric pressure as desired.

The temperature of this reaction can vary very widely. The temperature of this reaction may range from about 10 ℃ to about 200 ℃, alternatively from about 50 ℃ to about 150 ℃, alternatively from about 70 ℃ to about 130 ℃.

The reaction may be carried out in the presence of a diluent or a mixture of diluents. It is important to ensure that the reactants are in intimate contact with each other so that they react. This is an important consideration because the starting materials for the mannich condensation reaction include a relatively non-polar polyisobutyl-substituted hydroxyaromatic compound, and a relatively polar amino acid or ester derivative thereof. It is therefore necessary to find a suitable set of reaction conditions or diluents that will dissolve all the starting materials.

The diluent used for this reaction must be capable of dissolving the starting materials for this reaction and allowing the reacting materials to come into contact with each other. Mixtures of diluents can be used for this reaction. Diluents suitable for this reaction include water, alcohols (including methanol, ethanol, isopropanol, 1-propanol, 1-butanol, isobutanol, sec-butanol, butanediol, 2-ethylhexanol, 1-pentanol, 1-hexanol, ethylene glycol, and the like), DMSO, NMP, HMPA, cellulosic solvents, diglyme, various ethers (including diethyl ether, THF, diphenyl ether, dioxane, and the like), aromatic diluents (including toluene, benzene, o-xylene, m-xylene, p-xylene, mesitylene, and the like), esters, alkanes (including pentane, hexane, heptane, octane, and the like), and various natural and synthetic diluents (including 100 neutral oil, 150 neutral oil, polyalphaolefin, fischer-tropsch synthetic base oil, and the like), and mixtures of such diluents. Diluent mixtures that form two phases, such as methanol and heptane, are suitable diluents for this reaction.

The reaction may be carried out by first reacting the hydroxyaromatic compound with an alkali metal base, followed by addition of the amino acid or ester derivative thereof and the aldehyde, or the amino acid or ester derivative thereof may be reacted with the aldehyde, followed by addition of the hydroxyaromatic compound and the alkali metal base, and the like.

It is believed that the reaction of an amino acid such as glycine or an ester derivative thereof with an aldehyde such as formaldehyde may result in the intermediate formula

Which eventually forms a cyclic form

It is believed that these intermediates may be reacted with a hydroxyaromatic compound and a base to form the Mannich condensation products of the present invention.

Alternatively, it is believed that the reaction of the hydroxyaromatic compound with the aldehyde may result in the intermediate formula

It is also believed that such intermediate products may be reacted with an amino acid or ester derivative thereof and a base to form the Mannich condensation products of the present invention.

The reaction time may vary widely depending on the temperature. The reaction time may be from about 0.1 hour to about 20 hours, alternatively from about 2 hours to about 10 hours, alternatively from about 3 hours to about 7 hours.

The feed mole ratio (CMR) of the reactants can also vary over a wide range. Table I below gives a list of different formulae that may occur when different feed molar ratios are used. At a minimum, the oil-soluble Mannich condensation product should preferably contain at least one polyisobutyl-substituted phenol ring and one amino acid group, which links an aldehyde group and an alkali metal. The feed molar ratio of polyisobutyl-substituted phenol/aldehyde/amino acid/base for this molecule is also shown in Table II below, which is 1.0: 1.0. Other feed molar ratios are possible, and the use of other feed molar ratios may result in the formation of different molecules of different formulae.

TABLE II

Ashless dispersants

In addition to the Mannich reaction product described above, the lubricating oil composition of the present invention will further comprise at least one ashless dispersant. In general, suitable ashless dispersants may be polyalkylene succinic anhydride ashless dispersants, nitrogen-free ashless dispersants and basic nitrogen-containing ashless dispersants. Another such group suitable for use herein as a dispersant includes copolymers containing carboxylic acid esters having one or more other polar functional groups including amines, amides, imines, imides, hydroxyl groups, carboxyl groups, and the like. These products may be prepared by copolymerizing long chain alkyl acrylates or methacrylates with monomers having functional groups as described above. Such groups include alkyl methacrylate-vinyl pyrrolidone copolymers, alkyl methacrylate-dialkylaminoethyl methacrylate copolymers and the like, as well as high molecular weight amides and polyamides or esters and polyesters such as tetraethylenepentamine, polyvinylpolystearate and other polystearamides.

Polyalkylene succinic anhydride ashless dispersants include polyisobutenyl succinic anhydride (PIBSA). The number average molecular weight of the polyalkylene tail in the polyalkylene succinic anhydrides used herein will be at least about 350 or about 750 to about 3000 or about 900 to about 1100.

In one embodiment, a mixture of polyalkylene succinic anhydrides is used. In such an embodiment, the mixture may comprise a low molecular weight polyalkylene succinic anhydride component, such as a polyalkylene succinic anhydride having a number average molecular weight of about 350 to about 1000, and a high molecular weight polyalkylene succinic anhydride component, such as a polyalkylene succinic anhydride having a number average molecular weight of about 1000 to about 3000. In one embodiment, both the low and high molecular weight components are polyisobutenyl succinic anhydrides. Alternatively, polyalkylene succinic anhydride components of different molecular weights may be combined as a dispersant, as well as mixtures of other above-referenced dispersants as described above.

In general, polyalkylene succinic anhydrides are obtained from the reaction product of a polyalkylene, such as polyisobutylene, with maleic anhydride. In the preparation of such polyalkylene succinic anhydrides, conventional polyisobutenes, or high-methylvinylidene polyisobutenes, can be used. The polyalkylene succinic anhydrides may be prepared using conventional techniques such as heat, chlorination, free radical, acid catalysis or any other method known to those skilled in the art during the preparation process. Examples of suitable polyalkylene succinic anhydrides for use herein are the hot PIBSA (polyisobutenyl succinic anhydride) disclosed in U.S. patent 3,361,673; chlorinated PIBSA disclosed in U.S. patent 3,172,892; mixtures of hot and chlorinated PIBSA disclosed in U.S. patent 3,912,764; high succinic ratio PIBSA disclosed in U.S. patent 4,234,435; poly PIBSA disclosed in U.S. patents 5,112,507 and 5,175,225; high succinic ratio poly PIBSA disclosed in U.S. patents 5,565,528 and 5,616,668; free radical PIBSA disclosed in us patents 5,286,799, 5,319,030, and 5,625,004; PIBSA made from the high methylvinylidene polybutenes disclosed in U.S. Pat. nos. 4,152,499, 5,137,978 and 5,137,980; high succinic ratio PIBSA made from high methylvinylidene polybutene disclosed in European patent application publication EP 355895; trimer PIBSA disclosed in U.S. patent 5,792,729, sulfonic acid PIBSA disclosed in U.S. patent 5,777,025 and european patent application publication EP 542380; and purified PIBSA as disclosed in us patent 5,523,417 and european patent application EP 602863, the contents of which are incorporated herein by reference.

Nitrogen-free ashless dispersants include derivatives of polyalkylene succinic anhydrides, e.g. succinic acid, group I and/or group II mono or di-metal salts of succinic acid, by reaction of polyalkylene succinic anhydrides, acid chlorides or other derivatives with alcohols (e.g. HOR)¹Wherein R is¹Alkyl groups of 1 to 10 carbon atoms), and the like, and mixtures thereof.

The aforementioned polyalkylene succinic anhydride ashless dispersants and/or nitrogen-free ashless dispersants may be post-treated with a variety of different post-treatment agents as desired. For example, the aforementioned polyalkylene succinic anhydrides and/or nitrogen-free ashless dispersants may be reacted with a cyclic carbonate under conditions sufficient to cause the cyclic carbonate to react with hydroxyl groups. The reaction is typically carried out at a temperature in the range of from about 0 ℃ to about 250 ℃, alternatively from about 100 ℃ to about 200 ℃, alternatively from about 50 ℃ to about 180 ℃.

The reaction can be carried out unadulterated (neat) with polyalkylene succinic anhydrides or nitrogen-free ashless dispersants and cyclic carbonates combined in the correct proportions, either alone or in the presence of a catalyst (e.g., an acidic, basic or lewis acid catalyst). Examples of suitable catalysts include, but are not limited to, phosphoric acid, boron trifluoride, alkyl or aryl sulfonic acids, alkali or alkaline earth metal (alkali or alkaline) carbonates. The same solvents or diluents as described above for the preparation of polyalkylene succinic anhydrides may also be used for the cyclic carbonate work-up. In a preferred embodiment, the cyclic carbonate used herein is 1, 3-dioxolane (dioxolan) -2-one (ethylene carbonate).

The nitrogen-containing basic ashless (metal-free) dispersant contributes to the base number or BN (as can be determined according to ASTM D2896) of the lubricating oil composition to which it is added, without introducing additional sulfated ash. The basic nitrogen compound used to prepare the colloidal suspensions of the present invention must contain basic nitrogen, as determined according to ASTM D664 test or D2896. It is preferably oil soluble. The basic nitrogen compound is selected from the group consisting of succinimides, polysuccinimides, carboxylic acid amides, hydrocarbyl monoamines, hydrocarbyl polyamines, Mannich condensation products of hydrocarbyl-substituted phenols, formaldehyde and polyamines other than the Mannich reaction products described above, phosphoramides, thiophosphoramides, phosphonamides, dispersant viscosity index improvers, and mixtures thereof. These basic nitrogen-containing compounds are described below (where each must retain at least one basic nitrogen). Any nitrogen-containing composition may be post-treated by procedures known in the art using, for example, boron, so long as the composition continues to contain basic nitrogen.

Succinimide and polysuccinimide ashless dispersants that may be used in the lubricating oil compositions of the present invention are disclosed in a large number of documents and are known in the art. Specific basic types of succinimides and related materials summarized by the term "succinimide" are disclosed, for example, in U.S. Pat. nos. 3,219,666; 3,172,892; 3,272,746; 4,234,435 and 6,165,235, the contents of which are incorporated herein by reference. Succinic-based dispersants have a variety of different chemical structures. A succinic-based dispersant may be represented by the formula:

wherein each R¹Independently a hydrocarbyl group, such as a group derived from a polyolefin. Tong (Chinese character of 'tong')Often, the hydrocarbyl group is an alkyl group, such as a polyisobutyl group. Alternatively, R¹The group may contain from about 40 to about 500 carbon atoms, and these atoms may be represented in aliphatic form. R²Is an alkylene group, typically ethylene (C)₂H₄) A group.

The polyolefins from which the substituents are derived are typically homopolymers and interpolymers of polymerizable olefin monomers of 2 to about 16 carbon atoms, and usually 2 to 6 carbon atoms. The amine reacted with the succinic acylating agent to form the carboxylic dispersant composition may be a mono-or polyamine.

The term "succinimide" is understood in the art to include a variety of amides, imides, and amidines that may also be formed. However, the predominant product is succinimide, and this form is generally accepted to refer to the reaction product of an alkenyl substituted succinic acid or anhydride and a nitrogen-containing compound. In a preferred embodiment, due to its commercial availability, the succinimides are those succinimides prepared from hydrocarbyl succinic anhydrides and ethylene amines or polyamines wherein the hydrocarbyl group contains from about 24 to about 350 carbon atoms, the ethylene amines being characterized in particular by ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine and higher molecular weight polyethylene amines. Particularly preferred are those succinimides prepared from polyisobutenyl succinic anhydride of 70 to 128 carbon atoms and tetraethylene pentamine or higher molecular weight polyethylene amines or mixtures of polyethylene amines, e.g., having an average molecular weight of about 205 daltons in the mixture. In one embodiment of the present invention, the ashless dispersant used in the lubricating oil composition is a disuccinimide derived from polyisobutenyl groups having a number average molecular weight of from about 700 to about 2300.

The term "succinimide" also includes co-oligomers of hydrocarbyl succinic acids or anhydrides and secondary polyamines comprising at least one tertiary amine nitrogen in addition to two or more secondary amine groups. Typically, such compositions have an average molecular weight of 1,500 to 50,000. Typical compounds will be prepared by reacting polyisobutenyl succinic anhydride and ethylene bipiperazine.

If desired, the ashless succinimide and polysuccinimide dispersants described above may be post-treated with a variety of different post-treatment agents, such as cyclic carbonates, as described above. One or more of the nitrogens of the polyamine portion of the resulting post-treatment product is substituted with a hydroxyhydrocarbyloxycarbonyl group, a hydroxypoly (oxyalkylene) oxycarbonyl group, a hydroxyalkylene group, a hydroxyalkylenepoly (oxyalkylene) group, or a mixture thereof.

The aforementioned succinimides and polysuccinimides, including the post-treatment compositions described above, may also be reacted to form borated dispersants. In addition to boric acid, examples of suitable boron compounds include boron oxides, boron halides and esters of boric acid. Generally, from about 0.1 to about 1 equivalent of boron compound per equivalent of basic nitrogen or hydroxyl group may be employed in the compositions of the present invention.

Carboxylic amide ashless dispersants are also used as nitrogen-containing ashless dispersants. Such compounds are typically disclosed in U.S. Pat. No. 3,405,064, the contents of which are incorporated herein by reference. These compounds are typically prepared by reacting a carboxylic acid or anhydride or ester thereof having at least 12 to about 350 aliphatic carbon atoms in the main aliphatic chain and, if desired, sufficient pendant aliphatic groups to tend to render the molecule oil soluble with an amine or a hydrocarbyl polyamine such as ethylene amine to give a mono or polycarboxylic acid amide. In one embodiment, the carboxylic acid amide may be represented by the formula (1) R²Carboxylic acid of COOH, wherein R²Is C_12-20Alkyl groups or mixtures of such acids with polyisobutenyl carboxylic acids in which the polyisobutenyl group contains from 72 to 128 carbon atoms and (2) ethylene polyamines, especially triethylene tetramine or tetraethylene pentamine or mixtures thereof.

Another class of suitable nitrogen-containing ashless dispersants are hydrocarbyl monoamines and hydrocarbyl polyamines, preferably of the type disclosed in U.S. Pat. No. 3,574,576, the contents of which are incorporated herein by reference. A hydrocarbyl group, preferably an alkyl or alkenyl group having one or two sites of unsaturation, typically containing from 9 to about 350, or from about 20 to about 200 carbon atoms (olefinic). In one embodiment, suitable hydrocarbyl polyamines are, for example, those derivatized by reacting polyisobutenyl chloride and a polyalkylene polyamine such as an ethylene amine, e.g., ethylene diamine, diethylene triamine, tetraethylene pentamine, 2-aminoethyl piperazine, 1, 3-propylene diamine, 1, 2-propylene diamine, and the like.

Yet another class of suitable nitrogen-containing ashless dispersants are Mannich compounds other than the Mannich reaction products described above. These compounds are prepared from phenols or C_9-200Alkyl phenols, aldehydes such as formaldehyde or formaldehyde precursors such as paraformaldehyde (para-formaldehyde) and amine compounds. The amine may be a mono-or polyamine, and typical compounds are prepared from alkylamines such as methylamine or ethyleneamines such as diethylenetriamine or tetraethylenepentamine and the like. The phenolic material may be sulfurized and is preferably dodecylphenol or C_80-100An alkylphenol. Typical mannich bases useful in the present invention are disclosed in U.S. patents 3,539,663, 3,649,229, 3,368,972 and 4,157,309, the contents of which are incorporated herein by reference. U.S. patent 3,539,663, the contents of which are incorporated herein by reference, discloses a process for preparing a mixture of an alkylphenol having at least 50 carbon atoms, preferably 50 to 200 carbon atoms, and formaldehyde and an alkylene polyamine, HN (ANH)_nH wherein a is a saturated divalent alkyl hydrocarbon of 2 to 6 carbon atoms and n is 1-10, and the condensation product of the alkylene polyamine may be further reacted with urea or thiourea. The utilization of these mannich bases as starting materials for the preparation of lubricating oil additives can generally be significantly improved by treating the mannich bases using conventional techniques to incorporate boron into the compounds.

Yet another class of suitable nitrogen-containing ashless dispersants are phosphoramides and phosphonamides, as disclosed, for example, in U.S. Pat. Nos. 3,909,430 and 3,968,157, the contents of which are incorporated herein by reference. These compounds can be prepared by forming a phosphorus compound having at least one P-N bond. They can be prepared, for example, by reacting phosphorus oxychloride with a hydrocarbyl diol in the presence of a monoamine, or by reacting phosphorus oxychloride with a difunctional secondary amine and a monofunctional amine. Thiophosphoramides can be prepared by reacting an unsaturated hydrocarbon compound containing from 2 to 450 or more carbon atoms, such as polyethylene, polyisobutylene, polypropylene, ethylene, 1-hexene, 1, 3-hexadiene, isobutylene, 4-methyl-1-pentene, and the like, with phosphorus pentasulfide and a nitrogen containing compound as defined above, particularly an alkylamine, alkyldiamine, alkylpolyamine or alkyleneamine, such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and the like.

Suitable ashless dispersants may also include amine dispersants, which are the reaction product of a relatively high molecular weight aliphatic halide and an amine, preferably a polyalkylene polyamine. Examples of such amine dispersants include, for example, those disclosed in U.S. Pat. nos. 3,275,554, 3,438,757, 3,454,555, and 3,565,804, the contents of which are incorporated herein by reference.

Suitable ashless dispersants may also be polymeric, which are interpolymers of oil soluble monomers such as decyl methacrylate, vinyl decyl ether, and high molecular weight olefins with monomers containing polar substituents. Polymeric dispersants include, for example, those described in U.S. Pat. nos. 3,329,658, 3,449,250 and 3,666,730, the contents of which are incorporated herein by reference.

Generally, the ashless dispersant is present in the lubricating oil compositions of the present invention in an amount in the range of from about 0.1 to about 10 wt.%, based on the total weight of the lubricating oil composition. In one embodiment, the ashless dispersant is present in the lubricating oil composition of the present invention in an amount in the range of about 1 to about 8 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may also contain other conventional additives which may impart or improve any of the targeted characteristics of the lubricating oil composition in which these additives are dispersed or dissolved. Any additive known to those skilled in the art may be used in the lubricating oil compositions disclosed herein. Certain suitable additives have been disclosed in Mortier et al, "Chemistry and Technology of Lubricants", second 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. For example, the lubricating oil composition may be blended with antioxidants, anti-wear agents, detergents such as metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoaming agents, co-solvents, package compatibilisers, anti-corrosion agents, ashless dispersants, dyes, extreme pressure agents and the like, and mixtures thereof. Various additives are known and commercially available. These additives or their analogous compounds can be used to prepare the lubricating oil compositions of the present invention by conventional blending procedures.

In general, when used, the concentration of each additive in the lubricating oil composition can range from about 0.001 wt.% to about 20 wt.%, from about 0.01 wt.% to about 15 wt.%, or from about 0.1 wt.% to about 10 wt.%, based on the total weight of the lubricating oil composition.

Non-limiting examples of suitable antioxidants include amine-based antioxidants (e.g., alkyl diphenylamines such as dinonylated diphenylamine, dioctylated diphenylamine, and octylated/butylated diphenylamine, phenyl-alpha-naphthylamine, alkyl-or arylalkyl-substituted phenyl-alpha-naphthylamine, alkylated p-phenylenediamine, tetramethyldiaminodiphenylamine, and the like), phenolic antioxidants (e.g., 2-tert-butylphenol, 4-methyl-2, 6-di-tert-butylphenol, 2,4, 6-tri-tert-butylphenol, 2, 6-di-tert-butyl-p-cresol, 2, 6-di-tert-butylphenol, 4,4 ' -methylenebis- (2, 6-di-tert-butylphenol), 4,4 ' -thiobis (6-di-tert-butyl-o-cresol), and the like), sulfur based antioxidants (e.g., dilauryl-3, 3 ' -thiodipropionate, sulfurized phenolic antioxidants, and the like), phosphorus based antioxidants (e.g., phosphites, and the like), zinc dithiophosphate, oil soluble copper compounds, and combinations thereof the amount of antioxidant can be from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

A detergent generally comprises a polar head having a long hydrophobic tail.

Detergents that may be used include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates, and naphthenates, as well as other oil-soluble metal carboxylates, particularly alkali or alkaline earth metals, such as barium, sodium, potassium, lithium, calcium, and magnesium.

Overbased metal detergents are typically formed by carbonating a mixture of a hydrocarbon, a detergent acid such as a sulfonic acid, carboxylate, or the like, a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and a promoter such as xylene, methanol, and water₂Neutralized to form a sulfonate salt.

The overbased detergent may be low overbased, e.g., an overbased salt having less than 100 BN. in one embodiment, the BN of the low overbased salt may be from about 5 to about 50, in another embodiment, the BN of the low overbased salt may be from about 10 to about 30, in yet another embodiment, the BN of the low overbased salt may be from about 15 to about 20.

The overbased detergent may be medium overbased, e.g., an overbased salt having a BN of about 100 to about 250. in one embodiment, the BN of the medium overbased salt is about 100 to about 200. in another embodiment, the BN of the medium overbased salt is about 125 to about 175.

The overbased detergent may be highly overbased, e.g., an overbased salt having a BN greater than 250.

Suitable hydroxyaromatic compounds include mononuclear monohydroxy and polyhydroxy aromatic hydrocarbons having from 1 to 4, and preferably from 1 to 3, hydroxyl groups.

The alkyl-substituted portion of the alkali metal or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is derived from an alpha-olefin having from about 10 to about 80 carbon atoms the olefin employed may be linear, isomerized linear, branched or partially branched linear.

In one embodiment, the mixture of linear olefins that may be used is a mixture of normal alpha olefins selected from olefins having from about 12 to about 30 carbon atoms per molecule.

In another embodiment, the olefin is a branched olefinic propylene oligomer having from about 20 to about 80 carbon atoms or mixtures thereof, i.e., a branched olefinic diameter derived from the polymerization of propylene.

In one embodiment, 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 an alkyl-substituted hydroxyaromatic carboxylic acid, for exampleThe alkyl group of the alkaline earth metal salt detergent of alkyl-substituted hydroxybenzoic acid is C₂₀In another embodiment, the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is an alkali or alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid, derived from an alkyl-substituted hydroxybenzoic acid, wherein the alkyl group is the residue of a n-alpha-olefin comprising at least 75 mol% C₂₀Or higher normal alpha olefins.

In another embodiment, at least about 50 mol% (e.g., at least about 60 mol%, at least about 70 mol%, at least about 80 mol%, at least about 85 mol%, or 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 an alkyl-substituted hydroxyaromatic carboxylic acid, e.g., the alkyl group of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid, is about C₁₄To about C₁₈.

The resulting alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid will be a mixture of ortho and para isomers in one embodiment, the product will comprise about 1 to 99% ortho and 99 to 1% para isomers in another embodiment, the product will comprise about 5 to 70% ortho and 95 to 30% para isomers.

Typically, the alkali or alkaline earth metal salt of an overbased alkyl-substituted hydroxyaromatic carboxylic acid is one in which the BN of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid has been increased by, for example, the addition of a source of base (e.g., lime) and an acidic overbased compound (e.g., carbon dioxide).

The sulfonates can be prepared from sulfonic acids, which are typically obtained by sulfonating alkyl-substituted aromatic hydrocarbons, such as those obtained by fractional distillation of petroleum or by alkylation of aromatic hydrocarbons examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl or their halogenated derivatives.

The amount of metal compound is selected based on the target TBN of the final product, but typically ranges from about 100 to about 220 weight percent (preferably at least about 125 weight percent) of the target stoichiometry.

Sulfurized phenols can be prepared by reacting a phenol with sulfur or a sulfur-containing compound, such as hydrogen sulfide, sulfur monohalide, or sulfur dihalide, to form a product, typically a mixture of compounds, in which 2 or more phenols are bridged by a sulfur-containing bridge.

Typically, the amount of other detergents may be from about 0.001 wt.% to about 25 wt.%, from about 0.05 wt.% to about 20 wt.%, or from about 0.1 wt.% to about 15 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may contain one or more friction modifiers which may reduce friction between moving parts. Derivatives of fatty carboxylic acids (e.g., alcohols, esters, borates, amides, metal salts, etc.); mono-, di-or trialkyl-substituted phosphoric or phosphonic acids; an aptamer (e.g., an ester, an amide, a metal salt, etc.) of a mono-, di-, or trialkyl-substituted phosphoric-or phosphonic acid; mono-, di-or trialkyl-substituted amines; in certain embodiments, examples of friction modifiers include, but are not limited to, alkoxylated fatty amines; boric acid flower fatty epoxide; fatty phosphites, fatty epoxides, fatsAmines, borated alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerides, borated glycerides; and fatty imidazolines as disclosed in U.S. patent 6,372,696, the contents of which are incorporated herein by reference; from C₄To C₇₅Or C₆To C₂₄Or C₆To C₂₀The amount of friction modifier may be from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

Non-limiting examples of suitable antiwear agents include zinc dithiophosphate, metal (e.g., Pb, Sb, Mo, etc.) salts of dithiophosphates, metal (e.g., Zn, Pb, Sb, Mo, etc.) salts of dithiocarbamates, metal (e.g., Zn, Pb, Sb, etc.) salts of fatty acids, boron compounds, phosphate esters, phosphite esters, amine salts of phosphate esters or amine salts of thiophosphate esters, reaction products of dicyclopentadiene and thiophosphoric acids, and combinations thereof.

In certain embodiments, the antiwear agent is a dihydrocarbyl dithiophosphate metal salt, such as a zinc dialkyldithiophosphate compound, the metal of the dihydrocarbyl dithiophosphate metal salt may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel, or copper, in certain embodiments, the metal is zinc, in other embodiments, the alkyl group of the dihydrocarbyl dithiophosphate metal salt has from about 3 to about 22 carbon atoms, from about 3 to about 18 carbon atoms, from about 3 to about 12 carbon atoms, or from about 3 to about 8 carbon atoms.

The amount of dihydrocarbyl dithiophosphate metal salt, including the amount of zinc dialkyl dithiophosphate salt in the lubricating oil compositions disclosed herein, is determined in terms of the amount of phosphorus in certain embodiments, the lubricating oil compositions disclosed herein have a phosphorus content of from about 0.01 wt.% to about 0.14 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may contain one or more foam inhibitors or defoamers, which can break up foam in the oil. Any foam inhibitor or defoamer known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable foam inhibitors or defoamers include silicone oils or polydimethylsiloxanes, fluorosilicones, alkoxylated fatty acids, polyethers (e.g., polyethylene glycol), branched polyvinyl ethers, alkyl acrylate polymers, alkyl methacrylate polymers, polyalkoxyamines, and combinations thereof. In certain embodiments, the foam inhibitor or defoamer comprises glycerol monostearate, polyethylene glycol palmitate, trialkyl monothiophosphate, esters of sulfonated ricinoleic acid, benzoylacetone, methyl salicylate, glycerol monooleate, or glycerol dioleate. The amount of foam inhibitor or defoamer can be from about 0.001 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may comprise one or more pour point depressants which may lower the pour point of the lubricating oil composition. Any pour point depressant known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable pour point depressants include polymethacrylates, alkyl acrylate polymers, alkyl methacrylate polymers, di (tetra-paraffinphenol) phthalate, condensates of tetra-paraffinphenol, condensates of chlorinated paraffins with naphthalene, and combinations thereof. In certain embodiments, the pour point depressant comprises ethylene-vinyl acetate copolymers, condensates of chlorinated paraffins and phenols, polyalkylstyrenes, and the like. The amount of pour point depressant may be from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

In one embodiment, the lubricating oil composition of the present invention does not comprise one or more demulsifiers. In another embodiment, the lubricating oil composition of the present invention may comprise one or more demulsifiers that can promote oil-water separation of the lubricating oil composition exposed to water or steam. Any demulsifier known to those skilled in the art can be used in the lubricating oil composition. Non-limiting examples of suitable demulsifiers include anionic surfactants (e.g., alkyl-naphthalene sulfonates, alkylbenzene sulfonates, and the like), nonionic alkoxylated alkylphenol resins, polymers of alkylene oxides (e.g., polyethylene oxide, polypropylene oxide, block copolymers of ethylene oxide, propylene oxide, and the like), esters of oil soluble acids, polyoxyethylene sorbitan esters, and combinations thereof. The amount of demulsifier can be from about 0.01 wt% to about 10 wt%, from about 0.05 wt% to about 5 wt%, or from about 0.1 wt% to about 3 wt%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may contain one or more corrosion inhibitors, which may reduce corrosion. Any corrosion inhibitor known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable corrosion inhibitors include half esters or amides of dodecyl succinic acid, phosphate esters, thiophosphate esters, alkyl imidazolines, sarcosines, and combinations thereof. The amount of corrosion inhibitor may be from about 0.01 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may contain one or more Extreme Pressure (EP) agents which can prevent the sliding metal surfaces from seizing under extreme pressure conditions. Any extreme pressure agent known to those skilled in the art may be used in the lubricating oil composition. Typically, extreme pressure agents are compounds that can chemically bond with metals to form a surface film that prevents rough welding to the opposing metal surface under high loads. Non-limiting examples of suitable extreme pressure agents include sulfurized animal or vegetable fats or oils, sulfurized animal or vegetable fatty acid esters, fully or partially esterified esters of trivalent or pentavalent acids of phosphorus, sulfurized olefins, dihydrocarbyl polysulfides, sulfurized diels-alder adducts, sulfurized dicyclopentadiene, sulfurized or co-sulfurized mixtures of fatty acid esters and monounsaturated olefins, co-sulfurized mixtures of fatty acids, fatty acid esters and alpha-olefins, functionally substituted dihydrocarbyl polysulfides, thioaldehydes, thioketones, cyclic sulfur compounds, sulfur-containing acetal derivatives, co-sulfurized blends of terpenes and acyclic olefins, and polysulfide olefin products, amine salts of phosphoric acid esters or amine salts of thiophosphoric acid esters, and combinations thereof. The amount of extreme pressure agent may be from about 0.01 wt% to about 5 wt%, from about 0.05 wt% to about 3 wt%, or from about 0.1 wt% to about 1 wt%, based on the total weight of the lubricating oil composition.

The lubricating oil composition of the present invention may contain one or more rust inhibitors, which can inhibit corrosion of ferrous metal surfaces. Any rust inhibitor known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable rust inhibitors include nonionic polyoxyalkylene agents such as 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; a dicarboxylic acid; a metal soap; fatty acid amine salts; metal salts of heavy sulfonic acids; partial carboxylic acid esters of polyhydric alcohols; a phosphorus ester; (lower) alkenyl succinic acids; partial esters and nitrogen-containing derivatives thereof; synthetic alkaryl sulfonates such as metal dinonyl naphthalene sulfonate; and the like, and mixtures thereof. The amount of rust inhibitor can be about 0.01 wt.% to about 10 wt.%, about 0.05 wt.% to about 5 wt.%, or about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil compositions of the present invention may comprise one or more multifunctional additives. Non-limiting examples of suitable multifunctional additives include sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum organophosphophosphate, oxymolybdenum monoglycerol, molybdenum diethoxylate amide, amine-molybdenum complexes, and sulfur-containing molybdenum complexes.

The lubricating oil composition of the present invention may comprise one or more viscosity index improvers. Non-limiting examples of suitable viscosity index improvers include, but are not limited to, olefin copolymers such as ethylene-propylene copolymers, styrene-isoprene copolymers, hydrated styrene-isoprene copolymers, polybutenes, polyisobutylenes, polymethacrylates, vinylpyrrolidone and methacrylate copolymers, and dispersant type viscosity index improvers. These viscosity modifiers may optionally be grafted using a grafting material such as maleic anhydride, and the grafting material may be reacted with, for example, an amine, an amide, a nitrogen-containing heterocyclic compound, or an alcohol to form a multifunctional viscosity modifier (dispersant-viscosity modifier). Other examples of viscosity modifiers include star polymers (e.g., star polymers comprising isoprene/styrene/isoprene triblock). Yet another example of a viscosity modifier includes a low Brookfield viscosity and high shear stability polyalkyl (meth) acrylate, a functionalized polyalkyl (meth) acrylate having dispersant characteristics of high Brookfield viscosity and high shear stability, a polyisobutylene having a weight average molecular weight of 700 to 2,500 daltons, and mixtures thereof. The amount of viscosity index improver can be from about 0.01 wt.% to about 25 wt.%, from about 0.05 wt.% to about 20 wt.%, or from about 0.3 wt.% to about 15 wt.%, based on the total weight of the lubricating oil composition.

The lubricating oil composition of the present invention may comprise one or more metal deactivators. Non-limiting examples of suitable metal deactivators include bis-salicylidene propylenediamine, triazole derivatives, thiadiazole derivatives, and mercaptobenzimidazole.

If desired, the at least one Mannich reaction product (b) and/or the at least one ashless dispersant (c) may be provided separately or together as an additive package or concentrate, wherein the at least one Mannich reaction product (b) and/or the at least one ashless dispersant (c), and optionally together with the aforementioned lubricant additives, are incorporated into a substantially inert, normally liquid, organic diluent such as mineral oil, naphtha, benzene, toluene or xylene to form an additive concentrate. These concentrates typically contain about 20 wt% to about 80 wt% diluent. Typically, a neutral oil having a viscosity of about 4 to about 8.5cSt at 100 deg.C, and preferably about 4 to about 6cSt, will be used as the diluent, although synthetic oils and other organic liquids compatible with the additives and the final lubricating oil may also be used. The additive package will typically contain one or more of the various additives referenced above in targeted amounts and proportions to help direct the combination with the requisite amount of oil of lubricating viscosity.

The lubricating oil compositions disclosed herein are used to lubricate an internal combustion engine, such as a spark-ignition engine or a compression-ignition diesel engine, such as a heavy-duty diesel engine or a compression-ignition diesel engine equipped with at least one Exhaust Gas Recirculation (EGR) system; a catalytic converter; and a particulate trap. Such engine oil compositions can be used to lubricate all major moving parts in any reciprocating internal combustion engine, reciprocating compressor and crankcase design steam engine. In automotive applications, the engine oil composition may also be used to cool hot engine components, keep the engine free from rust and deposits, and seal rings and valves to avoid leaking gas.

For heavy duty diesel engines, the main service category is light, medium and heavy duty diesel engines as disclosed in US 40 CFR 86.090-2. Factors upon which this classification is based are, for example, total vehicle weight (GVW), vehicle usage and mode of operation, other vehicle design features, engine horsepower, and other engine design and operating characteristics. The following is a general description of the main service categories for heavy duty diesel engines:

(1) light duty heavy duty diesel engines are typically non-bushed and are not designed to be rebuilt; their rated horsepower is typically 70 to 170. Types of bodies in this group may include heavy duty vehicle assemblies for light duty truck chassis, vans, multi-stop vans, recreational vehicles, and certain single-axle linear trucks. Typical applications for such engines include personal transportation, light duty commercial traction and transportation, passenger service, agriculture and construction. The engines in this group are typically used in vehicles where GVW is typically less than 19,500 pounds.

(2) Medium heavy duty diesel engines may be bushed or non-bushed and may be designed and rebuilt; their rated horsepower is typically 170 to 250. Types of bodies in this group may include school buses, two-axis line trucks, city tractors, and a variety of different special purpose vehicles, such as compact dump trucks and garbage trucks with compressors to compress the garbage. Typical applications for such engines include commercial short haul traction and urban transportation and pickup. The engines in this group are typically used in vehicles with GVW ranging from 19,500 to 33,000 pounds.

(3) Heavy duty diesel engines are bushed and designed for multiple rebuilds; their rated horsepower typically exceeds 250. The types of bodies in this group may include tractors, trucks and buses for long haul traction applications used between cities. The engines in this group are typically used in vehicles with GVW in excess of 33,000 pounds.

The following non-limiting examples are illustrative of the present invention.

Oil A, and comparative oils 1 and 2 were prepared and tested for piston cleanliness and piston ring sticking tendency according to the popular turbocharged DI test, the European passenger car Diesel Engine test (CEC-L-78-T-99), which is part of the ACEA A/B and C specifications published by the European Association of automotive manufacturers in 2004. This test is used to simulate repeated cycles of high speed operation followed by idle operation. A popular 1.9-liter in-line four-cylinder turbocharged direct injection automotive diesel engine (VW TDi) is mounted on the engine power meter station. A 54 hour, 2-phase program was executed that cycled between 30 minutes, 40 c pump idle and 150 minutes, 145 c pump full speed operation (4150rpm), with no intermediate oil fill. After the procedure, the pistons were evaluated for carbon and lacquer deposition and for trench carbon filling. The ring adhesion evaluation was performed on the piston ring. The results are shown in table III below. Oil A and each of comparative oils 1 and 2 were formulated to meet the specifications for SAE J300, revised 11 months in 2007 for a 0W-20 multigrade engine oil.

Oil A:

A0W-20 viscosity grade fully synthetic lubricating oil composition was prepared containing 79.23 wt.% group III base oil (4.1cSt, 100 deg.C), about 8 wt.% of an ethylene carbonate-treated disuccinimide dispersant, 3.0 wt.% of a Mannich reaction product (a reaction product of a polyisobutyl-substituted phenol (prepared using polyisobutylene having greater than 70 wt.% methylvinylidene isomer, 1,000 number average molecular weight), sodium glycinate, and formaldehyde), along with typical amounts of detergents, phosphorus-containing antiwear agents, antioxidants, friction modifiers, foam inhibitors, viscosity index improvers, pour point depressants, and diluent oils. Oil A had a sulphated ash content of about 0.79 wt%, a sulphur content of about 0.18 wt% and a phosphorus content of about 0.074 wt%.

Comparative oil 1: the formulation of oil A was substantially replicated, except that comparative oil 1 had 79.7 wt% group III base oil (4.1cSt, 100 ℃) and 1.50 wt% of the Mannich reaction product. Comparative oil 1 had a sulphated ash content of about 0.82 wt%, a sulphur content of about 0.18 wt% and a phosphorus content of about 0.07 wt%. Comparative oil 1 was a 0W-20 viscosity grade lubricating oil composition.

Comparative oil 2: the formulation of oil A was substantially replicated, except that comparative oil 2 had 79.7 wt% group III base oil (4.1cSt, 100 ℃) and 2.25 wt% of the Mannich reaction product. Comparative oil 2 had a sulphated ash content of about 0.79 wt%, a sulphur content of about 0.18 wt% and a phosphorus content of about 0.074 wt%. Comparative oil 2 was a 0W-20 viscosity grade lubricating oil composition.

TABLE III

The test type is as follows: VWTDI 2: SAE: 0W-20

The pass/fail scores according to the ACEA standards B4, B5, C3 and VW limits are listed in table IV below. If the VW 504/507 limit is passed, then the remaining specifications are passed.

TABLE IV

It will be understood that various modifications may be made to the embodiments disclosed herein. Accordingly, the foregoing description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the functions described above and performed as the best mode for carrying out the invention are for illustrative purposes only. Other configurations and methods may be made by those skilled in the art without departing from the scope and spirit of the present invention. In addition, other modifications will occur to those skilled in the art which are within the scope and spirit of the appended claims.

Claims

1. A lubricating oil composition comprising:

(a) greater than 65 wt.%, based on the total weight of the lubricating oil composition, of a base oil component having a kinematic viscosity (Kv) at 100 ℃ of from 3.5 to 4.5 centistokes (cSt);

(b) 3.0 to 10 wt.%, based on the total weight of the lubricating oil composition, of at least one mannich reaction product prepared by condensation of a polyisobutyl-substituted hydroxyaromatic compound, an aldehyde, an amino acid, or an ester derivative thereof, and an alkali metal base, wherein the polyisobutyl group is derived from polyisobutylene comprising at least 70 wt.% methylvinylidene isomer and has a number average molecular weight of 400 to 2,500; and

(c) at least one ashless dispersant different from component (b);

wherein the lubricating oil composition has a sulfur content of less than or equal to 0.30 wt.%, a phosphorus content of less than or equal to 0.09 wt.%, and a sulfated ash content of less than or equal to 1.60 wt.%, determined according to ASTM D874, based on the total weight of the lubricating oil composition; the lubricating oil composition is a multigrade lubricating oil composition that meets the specifications for 0W-X multigrade engine oil requirements for SAE J300, revised 11 months 2007, where X is 20, 30, 40, 50, or 60.

2. The lubricating oil composition of claim 1, which is an SAE0W-20 multigrade lubricating oil composition or a 0W-30 multigrade lubricating oil composition.

3. The lubricating oil composition of claim 1, having a sulfur content of 0.01 wt.% to 0.30 wt.%, a phosphorus content of 0.01 wt.% to 0.07 wt.%, and a sulfated ash content of 0.10 wt.% to 0.8 wt.%, as determined according to ASTM D874, based on the total weight of the lubricating oil composition.

4. The lubricating oil composition of claim 1, wherein the base oil component is a group III base oil.

5. Lubricating oil composition according to claim 1, comprising from 70 wt% to 85 wt%, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100 ℃ of from 3.5 to 4.5 cSt.

6. The lubricating oil composition of claim 1, wherein the polyisobutyl group of the polyisobutyl-substituted hydroxyaromatic compound is derived from polyisobutylene containing at least 90 wt.% methylvinylidene isomer.

7. The lubricating oil composition of claim 1, wherein the number average molecular weight of the polyisobutyl group of the polyisobutyl-substituted hydroxyaromatic compound is from 500 to 2,500.

8. The lubricating oil composition of claim 1, wherein the aldehyde is formaldehyde or paraformaldehyde, the base is an alkali metal hydroxide, and the amino acid is glycine.

9. The lubricating oil composition of claim 1, wherein at least one Mannich reaction product has the formula

Wherein each R is independently-CHR '-, wherein R' is a branched or linear alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkyl group having 6 to 10 carbon atomsAryl of (a), alkylaryl having from 7 to 20 carbon atoms, or arylalkyl having from 7 to 20 carbon atoms, R₁Is a polyisobutyl group derived from polyisobutylene containing at least 70 wt% methylvinylidene isomer and having a number average molecular weight of 400 to 2,500;

x is hydrogen, an alkali metal ion or an alkyl group having 1 to 6 carbon atoms;

w is- [ CHR "]-_mWherein each R "is independently H, alkyl having 1 to 15 carbon atoms, or substituted alkyl having 1 to 10 carbon atoms, and one or more substituents are selected from amino, amido, benzyl, carboxyl, hydroxyl, hydroxyphenyl, imidazolyl, imino, phenyl, sulfide, or mercapto; and m is an integer from 1 to 4;

y is hydrogen, alkyl having 1 to 10 carbon atoms, -CHR 'OH, wherein R' is as defined above, or

z is hydroxy, a hydroxyphenyl group of the formula:

or

Wherein, R, R₁Y', X and W are as defined above,

r, R therein₁Y', X and W are as defined above.

10. The lubricating oil composition of claim 1, wherein the at least one ashless dispersant is selected from the group consisting of a nitrogen-free ashless dispersant and a basic nitrogen-containing ashless dispersant.

11. The lubricating oil composition of claim 1, wherein the at least one ashless dispersant is selected from polyalkylene succinic anhydride ashless dispersants.

12. The lubricating oil composition of claim 1, wherein the at least one ashless dispersant is present in an amount of 0.1 wt.% to 10 wt.%, based on the total weight of the lubricating oil composition.

13. The lubricating oil composition of claim 1, further comprising one or more lubricating oil additives selected from the group consisting of antioxidants, detergents, rust inhibitors, dehazing agents, demulsifying agents, metal deactivating agents, friction modifiers, anti-wear agents, pour point depressants, antifoaming agents, co-solvents, package compatibilisers, anti-corrosion agents, dyes, extreme pressure agents and mixtures thereof.

14. The lubricating oil composition of claim 1, which is a heavy duty diesel engine lubricating oil composition.