CN115551976A

CN115551976A - Lubricating oil compositions comprising comb polymethacrylates and ethylene-based olefin copolymer viscosity modifiers

Info

Publication number: CN115551976A
Application number: CN202180034987.7A
Authority: CN
Inventors: 尾之内久成; 田中勲
Original assignee: Chevron Japan Ltd
Current assignee: Chevron Japan Ltd
Priority date: 2020-05-14
Filing date: 2021-05-14
Publication date: 2022-12-30
Also published as: WO2021229517A1; JP2023525328A; CA3182688A1; EP4150035A1; KR20230011331A

Abstract

A lubricating oil composition, such as a composition having a viscosity grade of SAE 0W-20 or less, is provided, comprising: (a) a major amount of an oil of lubricating viscosity, (b) a non-dispersant comb Polymethacrylate (PMA), and (c) a non-dispersant ethylene-based olefin copolymer. Also provided is a method for reducing wear in an internal combustion engine by lubricating the engine with the lubricating oil composition.

Description

Lubricating oil compositions comprising comb polymethacrylates and ethylene-based olefin copolymer viscosity modifiers

Technical Field

The disclosed technology relates to lubricating oil for internal combustion engines, in particular for spark ignition engines.

Background

Engine oils are blended with various additives to meet performance requirements. The challenge in engine oil formulation is to achieve simultaneous wear, deposit and varnish control while also achieving improved fuel economy.

One known way to increase the fuel economy of lubricating oil compositions is to reduce the viscosity (i.e., high Temperature High Shear (HTHS) viscosity). HTHS is a measure of the viscosity of a lubricating oil composition under severe engine conditions. However, this approach is reaching the limits of current equipment capabilities and specifications. The addition of an organic or organometallic friction modifier reduces the surface friction of the lubricating oil composition at a given viscosity and achieves better fuel economy. However, these additives often have deleterious effects, such as increased deposit formation, affect sealing, or they leave the wear-resistant component in limited surface locations insufficiently competitive, thereby not allowing the formation of a wear-resistant film, resulting in increased wear.

Viscosity modifiers are also widely used to increase the Viscosity Index (VI) of lubricating oil compositions, thickening the oil with increasing temperature. However, under high temperature and high stress conditions, degradation of the viscosity modifier may occur. When this occurs, the viscosity of the lubricating oil composition decreases, which may lead to increased engine wear.

Thus, despite advances in lubricant formulation technology, there remains a need for engine lubricants that provide adequate fuel economy while also providing excellent antiwear performance, particularly those having a viscosity grade of SAE 0W-20 or less.

Disclosure of Invention

In one aspect, the present disclosure provides a kinematic viscosity at 100 ℃ of less than 9.3mm ² A lubricating oil composition per s, comprising:

a) A major amount of an oil of lubricating viscosity;

b) Non-dispersant comb Polymethacrylate (PMA); and

c) The non-dispersant ethylene-based olefin copolymer.

Another aspect of the disclosure provides a method for reducing wear in an internal combustion engine, the method comprising using a kinematic viscosity at 100 ℃ of less than 9.3mm ² Lubricating oil composition of/s lubricates the engine, the lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

b) Non-dispersant comb Polymethacrylate (PMA); and

c) The non-dispersant ethylene-based olefin copolymer.

Yet another aspect of the present disclosure provides a lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

b) A non-dispersant comb Polymethacrylate (PMA) in an amount of 0.4wt.% to 1.9wt.%, based on the total weight of the lubricating oil composition; and

c) A non-dispersant ethylene-based olefin copolymer in an amount of 0.01wt.% to 0.36wt.%, based on the total weight of the lubricating oil composition.

Another aspect of the present disclosure provides a method for reducing wear in an internal combustion engine, the method comprising lubricating the engine with a lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

Detailed Description

To facilitate an understanding of the subject matter disclosed herein, a number of terms, abbreviations, or other abbreviations, as used herein, are defined below. Any terms, abbreviations or acronyms not defined are understood to have the ordinary meaning as used by the skilled artisan at the time of filing this application.

Definition of

In this specification, the following words and expressions, if used, have the meanings given below.

By "major amount" is meant more than 50wt.% of the composition.

By "minor amount" is meant less than 50wt.% of the composition, expressed as the total mass of the additive and all additives present in the composition, as active ingredient of the additive or additives.

"active ingredient" or "active" refers to an additive material that is not a diluent or solvent.

All percentages reported are weight percentages (wt.%) based on the active ingredient (i.e., without regard to the carrier or diluent oil), unless otherwise indicated.

The abbreviation "ppm" refers to parts per million by weight based on the total weight of the lubricating oil composition.

Kinematic Viscosity (KV) in mm at 100 ℃ ² Measured in/s and determined according to ASTM D445.

High Temperature High Shear (HTHS) viscosity at 150 ℃ is determined according to ASTM D4683.

The apparent viscosity at a temperature of-35 ℃ to-5 ℃ is measured by a cold start simulator according to ASTM D5293.

Metal-the term "metal" refers to an alkali metal, an alkaline earth metal, or mixtures thereof.

By oil-soluble or oil-dispersible material is meant that the amount of material required to provide the desired level of activity or performance can be incorporated by dissolving, dispersing or suspending in an oil of lubricating viscosity. Typically, this means that at least about 0.001wt.% of the material can be incorporated into the lubricating oil composition. For further discussion of the terms oil-soluble and oil-dispersible, in particular "stable dispersibility", see U.S. patent No. 4,320,019, the relevant teachings of which in this regard are expressly incorporated herein by reference.

The term "sulfated ash" as used herein refers to the non-combustible residue in lubricating oils resulting from detergents and metal additives. Sulfated ash can be determined according to ASTM D874.

The term "total base number" or "TBN" as used herein refers to the amount of base equivalent to milligrams of KOH in a gram of sample. Thus, a higher TBN value reflects a product with a stronger alkalinity and therefore a higher alkalinity. TBN is determined according to ASTM D2896.

The boron, calcium, magnesium, molybdenum, phosphorus, sulfur and zinc contents were determined according to ASTM D5185.

The weight average molecular weight (Mw) and the number average molecular weight (Mw) were measured by GPC (gel permeation chromatography) with polystyrene as a reference.

Shear Stability Index (SSI) was measured according to ASTM D7109.

All ASTM standards mentioned herein are the latest version of the filing date of this application.

Olefins-the term "olefins" refers to a class of unsaturated aliphatic hydrocarbons having one or more carbon-carbon double bonds obtained by a variety of processes. Unsaturated aliphatic hydrocarbons having one double bond are referred to as monoenes, and unsaturated aliphatic hydrocarbons having two double bonds are referred to as dienes, alkadienes, or diolefins. Alpha-olefins are particularly reactive because the double bond is between the first carbon and the second carbon. Exemplified are 1-octene and 1-octadecene used as starting points for moderately biodegradable surfactants. Linear olefins and branched olefins are also included in the definition of olefins.

While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been described herein in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.

It should be noted that not all activities described in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more other activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which the activities are performed.

Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. The benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as a critical, required, or essential feature or feature of any or all the claims.

The description and illustrated embodiments described herein are intended to provide a general understanding of the structure of the various embodiments.

As used herein, the terms "comprises," "comprising," "includes," "including," "contains," "containing," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited to only those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. In addition, unless expressly stated to the contrary, "or" means an inclusive or and not an exclusive or. For example, condition a or condition B is satisfied by any one of: a is true (or present) and B is false (or not present), a is false (or not present) and B is true (or present), and both a and B are true (or present).

The use of "a/an" is used to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the embodiments of the disclosure. This specification should be read to include one or at least one and the singular also includes the plural and vice versa unless it is clear that it is meant otherwise.

When referring to numerical values, the term "average" refers to an average, geometric mean, or median value. The group numbers corresponding to columns in the periodic Table of elements use the "New symbol" convention as seen in the CRC Handbook of Chemistry and Physics, 81 th edition (2000-2001).

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing activities are conventional and may be found in textbooks and other sources within the lubricant and oil and gas industries.

The specification and examples are not intended to be an exhaustive or comprehensive description of all of the elements and features of formulations, compositions, devices, and systems that utilize the structures or methods described herein. Individual embodiments may also be provided in combination in a single embodiment, and conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. In addition, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to the skilled artisan upon reading this specification only. Other embodiments may be utilized and derived from the disclosure, such that a structural substitution, logical substitution, or another change does not depart from the scope of the disclosure. The present disclosure is, therefore, to be considered as illustrative and not restrictive.

Oil/base oil component of lubricating viscosity

Oils of lubricating viscosity (sometimes referred to as "base stocks" or "base oils") are the major liquid component of lubricating oil compositions into which additives and possibly other oils are blended, for example, to produce the final lubricating oil composition. The base oil may be used to prepare concentrates and lubricating oil compositions therefrom, and may be selected from natural and synthetic oils and combinations thereof.

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

Synthetic oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, poly (1-hexenes), poly (1-octenes), and poly (1-decenes), alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, and di (2-ethylhexyl) benzenes), polyphenols (e.g., biphenyls, terphenyls, and alkylated polyphenols), and alkylated diphenyl ethers and alkylated diphenyl sulfides and their derivatives, analogs, and homologs.

Another suitable class of synthetic oils includes the esters of dicarboxylic acids (e.g., malonic acid, alkylmalonic acids, alkenylmalonic acids, succinic acid, alkylsuccinic acids and alkenylsuccinic acids, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, and phthalic acid) with a variety of alcohols (e.g., butanol, hexanol, dodecanol, 2-ethylhexanol, ethylene glycol, diethylene glycol monoether, and propylene glycol). Specific examples of such esters include dibutyl adipate, bis (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and complex esters formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

The base oil may be a renewable or bio-derived engine oil. Examples of such engine oils are disclosed in WO2016061050, which is incorporated herein by reference. According to some embodiments, the renewable or biologically derived base oil comprises a bio-based hydrocarbon, for example an isoparaffin derived from hydrocarbon terpenes such as myrcene, ocimene, and farnesene.

Esters useful as synthetic oils also include those made from C ₅ To C ₁₂ Esters of monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.

The base oil may be derived from fischer-tropsch synthesized hydrocarbons. Fischer-Tropsch synthesis of hydrocarbons from hydrocarbons containing H ₂ And CO is prepared using a fischer-tropsch catalyst. Such hydrocarbons typically require further processing to be used as base oils. For example, hydrocarbons may be hydroisomerized, hydrocracked and hydroisomerized, dewaxed or hydroisomerized and dewaxed using processes known to those skilled in the art.

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

Thus, the Base oils useful in preparing the lubricating Oil compositions of the present invention may be selected from any of the group I-V Base oils specified in the American Petroleum Institute (API) Base Oil interconvertibility Guidelines (API Publication 1509). Such base oil classifications are summarized in table 1 below:

TABLE 1

^(a) Group I to III are mineral oil basestocks.

^(b) Measured according to ASTM D2007.

^(c) Measured according to ASTM D2622, ASTM D3120, ASTM D4294 or ASTM D4927.

^(d) Measured according to ASTM D2270.

Base oils suitable for use herein are any of the categories corresponding to API group II, group III, group IV and group V oils and combinations thereof, preferably group III to group V oils, due to their specific volatility, stability, viscosity and cleanliness characteristics.

The base oil constitutes the major component of the lubricating oil composition and is present in an amount in the range of greater than 50wt.% to 99wt.% (e.g., 70wt.% to 95wt.% or 85wt.% to 95 wt.%).

The base oil may be selected from any synthetic or natural oil commonly used as crankcase lubricating oils for spark-ignited internal combustion engines. The kinematic viscosity of the base oil at 100 ℃ is generally 1.5mm ² S to 6mm ² And s. Kinematic viscosity at 100 ℃ of lubricating base oil of more than 6mm ² In the case of/s, the low-temperature viscosity characteristics may decrease, and sufficient fuel efficiency may not be obtained. At a kinematic viscosity of 1.5mm ² When/s or less, the oil film formed at the lubrication site is insufficient; therefore, lubrication is poor, and evaporation loss of the lubricating oil composition may increase.

However, in some implementationsIn the case of solutions, kinematic viscosities in excess of 6mm are required ² A base oil per s. For example, the total base oil may comprise a small portion of a higher distillate base oil, such as 10cSt polyalphaolefins.

Preferably, the base oil has a viscosity index of at least 90 (e.g., at least 95, at least 105, at least 110, at least 115, or at least 120). If the viscosity index is less than 90, not only the viscosity-temperature characteristics, thermal and oxidative stability and volatilization resistance decrease, but also the friction coefficient tends to increase; and abrasion resistance tends to be reduced.

The lubricating oil composition may be a multigrade oil having a viscosity grade of SAE 0W-XX, wherein XX is any one of 8, 10, 12, 16 and 20. According to a preferred embodiment, the lubricating oil composition has a viscosity grade SAE 0W-20.

The lubricating oil composition has a High Temperature High Shear (HTHS) viscosity at 150 ℃ of 3.0cP or less (e.g., 1.0cP to 3.0cP or 1.3cP to 3.0 cP), 2.8cP or less (e.g., 1.0cP to 2.8cP or 1.3cP to 2.8 cP), 2.7cP or less (e.g., 1.0cP to 2.7cP or 1.3cP to 2.7 cP), 2.6cP or less (e.g., 1.0cP to 2.6cP or 1.3cP to 2.6 cP), such as 2.5cP or less (e.g., 1.0cP to 2.5cP or 1.3cP to 2.5 cP), or 2.0cP or less (e.g., 1.0cP to 2.0 cP). According to exemplary embodiments, the lubricating oil composition has an HTHS viscosity at 150 ℃ of from 2.5cP to 2.6cP, from 2.55cP to less than 2.9cP, or from 2.55cP to 2.58cP.

The lubricating oil composition has a viscosity index of at least 135 (e.g., 135 to 400 or 135 to 250), at least 150 (e.g., 150 to 400 or 150 to 250), at least 165 (e.g., 165 to 400 or 165 to 250), at least 190 (e.g., 190 to 400 or 190 to 250), or at least 200 (e.g., 200 to 400 or 200 to 250). If the viscosity index of the lubricating oil composition is less than 135, it may be difficult to improve fuel efficiency while maintaining the required HTHS viscosity at 150 ℃. If the viscosity index of the lubricating oil composition exceeds 400, evaporation characteristics may be reduced, and defects may be caused due to insufficient solubility of additives and matching characteristics with sealing materials. According to exemplary embodiments, the lubricating oil composition has a viscosity index of 200 to 240, 203 to 235, 200 to 210, 220 to 225, or 230 to 240.

The lubricating oil composition has a kinematic viscosity of 3mm at 100 DEG C ² S to 12mm ² S (e.g., 3 mm) ² S to 11mm ² /s、5mm ² S to 9mm ² S or 6mm ² S to 8mm ² In/s). According to an exemplary embodiment, the lubricating oil composition has a kinematic viscosity at 100 ℃ of 6.9mm ² S to less than 9.3mm ² /s、7.4mm ² S to 7.8mm ² /s、7.45mm ² S to 7.76mm ² /s、7.4mm ² S to 7.5mm ² /s、7.5mm ² S to 7.6mm ² /s、7.6mm ² S to 7.7mm ² S or 7.7mm ² S to 7.8mm ² In the range of/s.

The lubricating oil composition has an apparent viscosity of 3600 to 3900mPa · s at a temperature in the range of 35 to-5 ℃, as measured by a Cold Cranking Simulator (CCS). According to exemplary embodiments, the lubricating oil composition has an apparent viscosity of 3600 to 3700, 3700 to 3800 or 3800 to 3900 mPa-s.

Typically, the sulfur content in the lubricating oil composition is less than or equal to about 0.7wt.%, based on the total weight of the lubricating oil composition. For example, the lubricating oil composition may have a sulfur content of about 0.01wt.% to 0.5wt.%, 0.01wt.% to 0.4wt.%, 0.01wt.% to 0.3wt.%, 0.01wt.% to 0.2wt.%, or 0.01wt.% to 0.10wt.%. In an embodiment, the lubricating oil composition has a sulfur content of less than or equal to about 0.60wt.%, less than or equal to about 0.50wt.%, less than or equal to about 0.40wt.%, less than or equal to about 0.30wt.%, less than or equal to about 0.20wt.%, or less than or equal to about 0.10wt.%, based on the total weight of the lubricating oil composition.

In one embodiment, the lubricating oil composition has a phosphorus content of less than or equal to about 0.08wt.%, for example, a phosphorus content of about 0.01wt.% to about 0.08wt.%, based on the total weight of the lubricating oil composition. In an embodiment, the lubricating oil composition has a phosphorus content of less than or equal to about 0.07wt.%, e.g., a phosphorus content of about 0.01wt.% to about 0.07wt.%, based on the total weight of the lubricating oil composition. In one embodiment, the lubricating oil composition has a phosphorus content of less than or equal to about 0.05wt.%, for example, a phosphorus content of about 0.01wt.% to about 0.05wt.%, based on the total weight of the lubricating oil composition.

In one embodiment, the amount of sulfated ash produced by the lubricating oil composition is less than or equal to about 1.00wt.% as determined by ASTM D874, e.g., about 0.10wt.% to about 1.00wt.% as determined by ASTM D874. In one embodiment, the amount of sulfated ash produced by the lubricating oil composition is less than or equal to about 0.80wt.% as determined by ASTM D874, e.g., the amount of sulfated ash is about 0.10wt.% to about 0.80wt.% as determined by ASTM D874. In one embodiment, the amount of sulfated ash produced by the lubricating oil composition is less than or equal to about 0.60wt.% as determined by ASTM D874, e.g., the amount of sulfated ash is about 0.10wt.% to about 0.60wt.% as determined by ASTM D874.

Suitably, the Total Base Number (TBN) of the lubricating oil composition of the present invention may be in the range of from 4 to 15mg KOH/g (e.g., from 5 to 12, 6 to 12, or 8 to 12mg KOH/g).

Viscosity modifier

Viscosity Modifiers (VM), sometimes referred to as Viscosity Index Improvers (VII), are present in lubricating oil compositions to impart high and low temperature operability. The viscosity modifier increases the viscosity of the lubricating oil composition at high temperatures, which increases the film thickness, while having a limited effect on viscosity at low temperatures.

Viscosity modifiers can be used to impart this single function, or can be multifunctional. Multifunctional viscosity modifiers may also be used as dispersants.

Examples of suitable viscosity modifiers are polymers and copolymers of methacrylates, butadiene, olefins or alkylated styrenes. Other suitable viscosity modifiers include copolymers of ethylene and propylene, hydrogenated block copolymers of styrene and isoprene, and polyacrylates (e.g., copolymers of various chain length acrylates).

The viscosity modifier may be present in the lubricating oil composition in a total amount of 0.001 to 10wt.%, based on the total weight of the lubricating oil composition. In other embodiments, the viscosity modifier may be present in a total amount of 0.01wt.% to 8wt.%, 0.1wt.% to 5wt.%, 0.4wt.% to 4wt.%, 0.6wt.% to 3wt.%, 0.7wt.% to 2wt.%, 1wt.% to 1.5wt.%, or 1.05wt.% to 1.44wt.%, based on the total weight of the lubricating oil composition. In some exemplary embodiments, the viscosity modifier is present in a total amount of 1.0wt.% to 1.2wt.%, 1.3wt.% to 1.4wt.%, or 1.4wt.% to 1.5wt.%, based on the total weight of the lubricating oil composition.

Particularly useful in the lubricating oil composition is a combination of a non-dispersant comb polymethacrylate (comb PMA) and at least one non-dispersant ethylene-based Olefin Copolymer (OCP).

Non-dispersant comb polymethacrylates

Non-dispersant comb polymethacrylates (comb PMA) are comb polymers and thus are macromolecules in which there is one long chain branch per repeat unit backbone.

In one embodiment, the non-dispersant comb PMA has a weight average molecular weight (Mw) of from 300,000g/mol to 600,000g/mol, 350,000g/mol to 550,000g/mol, 375,000g/mol to 500,000g/mol, or 390,000g/mol to 460,000g/mol.

In one embodiment, the non-dispersant comb PMA has a number average molecular weight (Mn) of 35,000g/mol to 105,000g/mol, 45,000g/mol to 95,000g/mol, 55,000g/mol to 85,000g/mol, or 65,000g/mol to 75,000g/mol. In another embodiment, the non-dispersant comb PMA has a number average molecular weight (Mn) of from 150,000g/mol to 250,000g/mol or from 200,000g/mol to 215,000g/mol.

In one embodiment, the non-dispersant comb PMA has a Shear Stability Index (SSI) of 0.1 to 1.0, 0.2 to 0.9, or 0.3 to 0.8.

Non-dispersant comb PMA of the lubricating oil composition may be described as described in US2017/0298287A1 and JP2019014802, the disclosures of which are incorporated herein by reference. Non-dispersant comb PMA may be obtained from Evonik

Viscosity index improvers 3-201 and/or 3-162.

According to one embodiment, the non-dispersant comb PMA is known as

3-201, which comprises comb PMA as the major resin component. The non-dispersant comb PMA had a weight average molecular weight (Mw) of 420,000g/mol, a number average molecular weight (Mn) of 70,946g/mol, and an Mw/Mn of 5.92. The compound has at least one constituent unit derived from a macromonomer having an Mn of 500 or greater. The non-dispersant comb PMA was present in an amount of 19wt.%, based on the total weight of the compound.

According to another embodiment, the non-dispersant comb PMA is known as

3-162, which further comprises comb PMA as the major resin component. The non-dispersant comb PMA had a weight average molecular weight (Mw) of 399,292g/mol, a number average molecular weight (Mn) of 205,952g/mol, an Mw/Mn of 1.94 and a Shear Stability Index (SSI) of 0.6.

According to another embodiment, the non-dispersant comb PMA is provided by a combination of compounds, e.g.

3-201 and

3-162.

The non-dispersant comb PMA is typically present in an amount of 0.4 to 2.0wt.%, 0.5 to 1.9wt.%, 0.6 to 1.8wt.%, 0.77 to 1.5wt.%, or 0.76 to 1.33wt.%, based on the total weight of the lubricating oil composition. According to one embodiment, the non-dispersant comb PMA is present in an amount of 0.4 to 1.9wt.%, based on the total weight of the lubricating oil composition.

Non-dispersant ethylene-based olefin copolymers

The lubricating oil composition also includes a non-dispersant ethylene-based Olefin Copolymer (OCP) as a viscosity modifier. In one embodiment, the non-dispersant ethylene-based olefin copolymer has a weight average molecular weight (Mw) of from 50,000g/mol to 200,000g/mol, 70,000g/mol to 180,000g/mol, or 90,000g/mol to 160,000g/mol. For example, a non-dispersant ethylene-based olefin copolymer can have a weight average molecular weight of 95,000g/mol to 105,000g/mol, 110,000g/mol to 115,000g/mol, or 145,000g/mol to 150,000g/mol.

In one embodiment, the non-dispersant ethylene-based olefin copolymer has a number average molecular weight (Mn) of from 20,000g/mol to 100,000g/mol, from 30,000g/mol to 90,000g/mol, or from 35,000g/mol to 85,000g/mol.

In one embodiment, the non-dispersant ethylene-based olefin copolymer has a Shear Stability Index (SSI) of from 10 to 70, 15 to 65, or 20 to 60.

Non-dispersant ethylene-based olefin copolymers may be described as follows, and as described in US2013/0203640, the disclosure of which is incorporated herein by reference.

In one embodiment, the non-dispersant ethylene-based olefin copolymer is an ethylene propylene copolymer.

In one embodiment, the non-dispersant ethylene-based olefin copolymer has a total content of ethylene of 35 to 70wt.%, or 40 to 65wt.%, based on the total weight of the non-dispersant ethylene-based olefin copolymer. In another embodiment, the non-dispersant ethylene-based olefin copolymer has a total ethylene content of 45wt.% to 60wt.%, based on the total weight of the non-dispersant ethylene-based olefin copolymer.

The lubricating oil composition may comprise more than one non-dispersant ethylene-based olefin copolymer. In one embodiment, the lubricating oil composition comprises a combination of a first ethylene-a-olefin copolymer (a) and a second ethylene-a-olefin copolymer (b). In such cases, the lubricating oil composition typically contains from about 30wt.% to about 70wt.% of (a) and from about 70wt.% to about 30wt.% of (b), based on the total amount of the first ethylene-a-olefin copolymer (a) and the second ethylene-a-olefin copolymer (b) in the lubricating oil composition. In another embodiment, the lubricating oil composition contains about 40 to 60wt.% of (a) and about 60 to about 40wt.% of (b), based on the total amount of the first ethylene-a-olefin copolymer (a) and the second ethylene-a-olefin copolymer (b) in the lubricating oil composition. In particular embodiments, the lubricating oil composition contains from about 50wt.% to about 54wt.% of (a) and from about 46wt.% to about 50wt.% of (b), based on the total amount of the first ethylene-a-olefin copolymer (a) and the second ethylene-a-olefin copolymer (b) in the lubricating oil composition.

In one embodiment, the first ethylene- α -olefin copolymer typically has a weight average molecular weight of from about 60,000g/mol to about 120,000g/mol. In another embodiment, the first ethylene- α -olefin copolymer typically has a weight average molecular weight of about 70,000g/mol to about 110,000g/mol. In one embodiment, the second ethylene-a-olefin copolymer typically has a weight average molecular weight of from about 60,000g/mol to about 120,000g/mol. In another embodiment, the second ethylene-a-olefin copolymer typically has a weight average molecular weight of about 70,000g/mol to about 110,000g/mol. In one embodiment, the weight average molecular weight of the composition of the first ethylene-a-olefin copolymer and the second ethylene-a-olefin copolymer is generally from about 60,000g/mol to about 120,000g/mol. In another embodiment, the weight average molecular weight of the composition of the first ethylene-a-olefin copolymer and the second ethylene-a-olefin copolymer is generally from about 70,000g/mol to about 110,000g/mol. In yet another embodiment, the weight average molecular weight of the composition of the first ethylene-a-olefin copolymer and the second ethylene-a-olefin copolymer is generally from about 80,000g/mol to about 100,000g/mol. The molecular weight distribution of each ethylene-alpha-olefin copolymer is typically less than about 2.5, more typically from about 2.1 to about 2.4. The polymer distribution as determined by GPC is generally unimodal.

The at least one non-dispersant ethylene-based olefin copolymer is typically present in an amount of 0.01wt.% to 1.5wt.%, 0.05wt.% to 1.0wt.%, 0.08wt.% to 0.4wt.%, 0.1wt.% to 0.5wt.%, or 0.15wt.% to 0.4wt.%, based on the total weight of the lubricating oil composition. According to one embodiment, the at least one non-dispersant ethylene-based olefin copolymer is present in an amount of 0.01wt.% to 0.36wt.%, based on the total weight of the lubricating oil composition.

Additive

In addition to the non-dispersant comb PMA and non-dispersant ethylene-based olefin copolymer viscosity modifiers described above, the lubricating oil compositions of the present disclosure may contain one or more additional performance additives that may impart or improve any desired characteristic of the lubricating oil composition. Any additive known to those skilled in the art may be used in the lubricating oil compositions disclosed herein. Some suitable Additives are described in R.M. Mortier et al "Chemistry and Technology of Lubricants" 3 rd edition, springer (2010) and L.R.Rudnik "Lubricant Additives: chemistry and Applications," second edition, CRC Press (2009).

For example, the lubricating oil composition may contain antioxidants, antiwear agents, metal detergents, dispersants, additional friction modifiers, corrosion inhibitors, demulsifiers, additional viscosity modifiers, pour point depressants, suds suppressors, and the like.

Typically, when used, the concentration of each additive in the lubricating oil composition can be 0.001wt.% to 10wt.% (e.g., 0.01wt.% to 5wt.% or 0.05wt.% to 2.5 wt.%) based on the total weight of the lubricating oil composition. Further, the total amount of additives in the lubricating oil composition can be 0.001wt.% to 20wt.% (e.g., 0.01wt.% to 15wt.% or 0.1wt.% to 10 wt.%) based on the total weight of the lubricating oil composition.

Antioxidant agent

Antioxidants retard the oxidative degradation of base oils during use. This degradation can result in deposits on the metal surface, the presence of sludge, or an increase in the viscosity of the lubricating oil composition. Useful antioxidants include hindered phenols, aromatic amines, and sulfurized alkylphenols, as well as their alkali metal and alkaline earth metal salts.

The hindered phenolic antioxidant can contain a secondary butyl group and/or a tertiary butyl group as a sterically hindering group. The phenolic group may be further substituted with a hydrocarbyl group and/or a bridging group connected to a second aryl group. Examples of suitable hindered phenol antioxidants include 2, 6-di-tert-butylphenol, 4-methyl-2, 6-di-tert-butylphenol, 2' -methylenebis (6-tert-butyl-4-methylphenol), 4' -bis (2, 6-di-tert-butylphenol), and 4,4' -methylenebis (2, 6-di-tert-butylphenol). The hindered phenolic antioxidant may be an ester or addition product derived from 2, 6-di-tert-butylphenol and an alkyl acrylate ester, wherein the alkyl group may contain from 1 to 18 carbon atoms.

Suitable aromatic amine antioxidants include diarylamines, such as alkylated diphenylamines (e.g., dioctyldiphenylamine, dinonyldiphenylamine), phenyl-alpha-naphthalenes, and alkylated phenyl-alpha-naphthalenes.

According to exemplary embodiments, the lubricating oil composition includes an amine antioxidant.

Antiwear agent

Antiwear agents help reduce wear of metal parts lubricated with the lubricating oil composition. Examples of antiwear agents include phosphorus-containing antiwear/extreme pressure agents (e.g., metal thiophosphates, phosphate esters, and salts thereof), phosphorus-containing carboxylic acids, esters, ethers, and amides, and phosphites. The antiwear agent may be zinc dialkyldithiophosphate (ZnDTP). Non-phosphorus-containing antiwear agents include borate esters (including borated epoxides), dithiocarbamate compounds, molybdenum-containing compounds, and sulfurized olefins.

According to one exemplary embodiment, the lubricating oil composition includes ZnDTP as an antiwear agent.

Metal detergent

Typical detergents are anionic materials that contain a long chain hydrophobic portion of the molecule and a smaller anionic or oleophobic hydrophilic portion of the molecule. The anionic portion of the detergent is typically derived from an organic acid, such as sulfuric acid, carboxylic acid, phosphorous acid, phenol, or mixtures thereof. The counter ion is typically an alkaline earth metal or an alkali metal.

In some embodiments, the lubricating oil compositions provided herein comprise at least a neutral or overbased metal detergent as an additive or additive component. In certain embodiments, the metal detergent in the lubricating oil composition acts as a neutralizer for acidic products within the lubricating oil composition. In certain embodiments, the metal detergent prevents the formation of deposits on engine surfaces. Detergents may have additional functions, such as oxidation resistance, depending on the nature of the acid used. In certain aspects, the lubricating oil composition comprises a metal detergent comprising an overbased detergent or a mixture of neutral and overbased detergents. The term "overbased" is intended to define an additive containing a metal content in excess of that stoichiometrically required for the particular metal and particular organic acid used. The excess metal is present in the form of particles of inorganic base (e.g., hydroxide or carbonate) surrounded by a metal salt sheath. The sheath serves to maintain the dispersion of the particles in the liquid oily carrier. The amount of excess metal is generally expressed as a ratio of the total equivalents of excess metal to the equivalents of organic acid, and is generally in the range of 0.1 to 30.

Some examples of suitable metal detergents include sulfurized or unsulfurized alkyl or alkenyl phenates, alkyl or alkenyl aromatic sulfonates, borated sulfonates, sulfurized or unsulfurized metal salts of polyhydroxy alkyl or alkenyl aromatic compounds, alkyl or alkenyl hydroxyaromatic sulfonates, sulfurized or unsulfurized alkyl or alkenyl naphthenates, metal salts of alkanoic acids, metal salts of alkyl or alkenyl polyacids, and chemical and physical mixtures thereof. Other examples of suitable metal detergents include metal sulfonates, phenates, salicylates, phosphonates, thiophosphonates, and combinations thereof. The metal may be any metal suitable for use in the preparation of a sulphonate, phenate, salicylate or phosphonate detergent. Non-limiting examples of suitable metals include alkali metals, basic metals, and transition metals. In some embodiments, the metal is Ca, mg, ba, K, na, li, and the like.

The metal detergent may be an overbased detergent, such as a Low Overbased (LOB), medium Overbased (MOB), or overbased (HOB) detergent.

The low overbased detergent may be an overbased salt having a Base Number (BN) of less than 100. 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 base number of an overbased detergent is measured in the presence of a diluent oil, rather than on an oil-free basis.

The medium overbased detergent may be an overbased salt having a BN of about 100 to about 250. In one embodiment, the BN of the moderately overbased salt may be from about 100 to about 200. In another embodiment, the BN of the moderately overbased salt may be from about 125 to about 175. The base number of an overbased detergent is measured in the presence of a diluent oil, rather than on an oil-free basis.

The overbased detergent may be an overbased salt having a BN above 250. In one embodiment, the BN of the highly overbased salt may be from about 250 to about 550. The base number of an overbased detergent is measured in the presence of a diluent oil, rather than on an oil-free basis.

Exemplary metal detergents that may be used in the lubricating oil composition include overbased calcium phenates. According to another exemplary embodiment, the lubricating oil composition comprises calcium LOB sulfonate, calcium HOB salicylate, and calcium MOB salicylate as detergents.

Ashless dispersants

The dispersant is an additive whose primary function is to keep solid and liquid contaminants in suspension, thereby passivating them and reducing engine deposits while reducing sludge deposition. For example, dispersants keep oil-insoluble materials produced by oxidation during use of the lubricating oil composition in a suspended state, thereby preventing sludge flocculation and precipitation or deposition on metal parts of the engine.

Dispersants are generally "ashless," non-metallic organic materials that do not substantially form ash on combustion, as opposed to metals and therefore ash-forming materials. They comprise a long hydrocarbon chain with a polar head, the polarity resulting from the inclusion of at least one nitrogen, oxygen or phosphorus atom. Hydrocarbons are lipophilic groups that impart oil solubility, having, for example, 40 to 500 carbon atoms. Thus, ashless dispersants may include an oil soluble polymeric backbone.

One preferred class of olefin polymers consists of polybutenes, particularly Polyisobutylene (PIB) or poly-n-butenes, and can be prepared, for example, by polymerization of C4 refinery streams.

Dispersants include, for example, derivatives of long chain hydrocarbon-substituted carboxylic acids, an example being derivatives of high molecular weight hydrocarbyl-substituted succinic acid. One notable group of dispersants consists of hydrocarbon-substituted succinimides, such as are made by reacting the above-mentioned acids (or derivatives) with nitrogen-containing compounds (advantageously polyalkylene polyamines, such as polyethylene polyamines.) a typical commercially available polyisobutenyl succinimide dispersant comprises a polyisobutylene polymer having a number average molecular weight in the range of 900 to 2500 functionalized with maleic anhydride and derivatized with a polyamine having a molecular weight in the range of 100 to 350.

Other suitable dispersants include succinate esters and ester-amides, mannich bases, polyisobutylene succinic acid (PIBSA), and other related components.

The succinic acid ester is formed by a condensation reaction between a hydrocarbon-substituted succinic anhydride and an alcohol or polyol. For example, the condensation product of a hydrocarbon-substituted succinic anhydride and pentaerythritol is a useful dispersant.

The succinate-amide is formed by a condensation reaction between a hydrocarbon-substituted succinic anhydride and an alkanolamine. For example, suitable alkanolamines include ethoxylated polyalkylpolyamines, propoxylated polyalkylpolyamines, and polyalkenyl polyamines, such as polyethylene polyamines. One example is propoxylated hexamethylene diamine.

Mannich bases are prepared from the reaction of an alkylphenol, formaldehyde and a polyalkylene polyamine. The alkylphenol may have a molecular weight of 800 to 2500.

The nitrogen-containing dispersant may be post-treated by conventional methods to improve its properties by reaction with any of a variety of reagents. Among these are boron compounds (e.g., boric acid) and cyclic carbonates (e.g., ethylene carbonate).

According to one exemplary embodiment, the lubricating oil composition includes a borated succinimide and an Ethylene Carbonate (EC) treated succinimide as the ashless dispersant.

Friction modifiers

The lubricating oil composition may comprise a friction modifier. A friction modifier is any such material that is capable of changing the coefficient of friction of a surface lubricated by any lubricant or liquid containing one or more materials. Friction modifiers include alkoxylated fatty amines, borated fatty epoxides, fatty phosphites, fatty epoxides, fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerol esters, borated glycerol esters, and fatty imidazolines. As used herein, the term "fat" refers to a hydrocarbon chain, typically a straight hydrocarbon chain, having from 10 to 22 carbon atoms.

According to exemplary embodiments, the lubricating oil composition includes an organomolybdenum compound, also referred to as a molybdenum-containing compound. The organomolybdenum compound contains at least molybdenum, carbon, and hydrogen atoms, but may also contain sulfur, phosphorus, nitrogen, and/or oxygen atoms. Suitable organo-molybdenum compounds include molybdenum dithiocarbamates, molybdenum dithiophosphates, and various organo-molybdenum complexes, such as molybdenum carboxylates, molybdenum esters, molybdenum amines, molybdenum amides, which may be obtained by reacting molybdenum oxide or ammonium molybdate with fats, glycerides, or fatty acids or fatty acid derivatives (e.g., esters, amines, and amides). The term "fat" refers to a carbon chain having from 10 to 22 carbon atoms, typically a straight carbon chain.

The molybdates may be prepared by the methods disclosed in US 4,889,647 and US 6,806,241 B2. Commercial example is manufactured by r.t. vanderbilt Company, inc

855 additive.

According to one exemplary embodiment, the lubricating oil composition includes molybdenum dithiocarbamate (MoDTC). Molybdenum dithiocarbamate (MoDTC) is an organomolybdenum compound represented by the following structure (1):

wherein R is ¹ 、R ² 、R ³ And R ⁴ Independently of one another, a straight or branched alkyl group having from 4 to 18 carbon atoms (e.g., from 8 to 13 carbon atoms).

The preparation of these compounds is well known in the literature and in U.S. Pat. nos. 3,356,702 and 4,098,705, which are incorporated herein by reference. Commercial examples include manufacture by r.t.vanderbilt Company incIs/are as follows

807、

822 and

2000. manufactured by ADEKA CORPORATION

165 and

515 and manufactured by Chemtura Corporation

MolyFM。

Trinuclear molybdenum dialkyldithiocarbamates are also known in the art, as taught in U.S. Pat. Nos. 5,888,945 and 6,010,987, both of which are incorporated herein by reference. The trinuclear molybdenum compound preferably has the formula Mo ₃ S ₄ (dtc) ₄ 、Mo ₃ S ₇ (dtc) ₄ And mixtures thereof, wherein dtc represents independently selected diorganodithiocarbamate ligands containing independently selected organic groups, and wherein these ligands have a sufficient number of carbon atoms in all organic groups of the ligands of the compound to render the compound soluble or dispersible in the lubricating oil composition.

According to another embodiment, the lubricating oil composition comprises molybdenum dithiophosphate (MoDTP). The MoDTP is an organomolybdenum compound represented by the following structure (2):

wherein R is ⁵ 、R ⁶ 、R ⁷ And R ⁸ Independently of one another, having from 4 to 18 carbon atoms (e.g. 8)To 13 carbon atoms).

Molybdenum carboxylates are described in U.S. Pat. No. RE 38,929 and U.S. Pat. No. 6,174,842, both of which are incorporated herein by reference. The molybdenum carboxylate may be derived from any oil soluble carboxylic acid. Typical carboxylic acids include naphthenic acid, 2-ethylhexanoic acid, and linolenic acid. The commercial sources of carboxylate produced from these specific acids are MOLYBDENUM NAP-ALL, MOLYBDENUM HEX-CEM and MOLYBDENUM LIN-ALL, respectively. The manufacturer of these products is the OMG OM Group.

Ammonium molybdate is prepared by the reaction of an acidic molybdenum source such as molybdenum trioxide, molybdic acid, ammonium molybdate and ammonium thiomolybdate with an oil soluble amine, optionally in the presence of a sulfur source such as sulfur, inorganic sulfides, polysulfides and carbon disulfide. Preferred amine compounds are polyamine dispersants commonly used in engine oil compositions. Examples of such dispersants are succinimide and mannich type dispersants. References to these dispersants are provided in U.S. Pat. nos. 4,259,194, 4,259,195, 4,265,773, 4,265,843, 4,727,387, 4,283,295, and 4,285,822.

In one embodiment, the molybdenum amine is a molybdenum-succinimide complex. Suitable molybdenum-succinimide complexes are described, for example, in U.S. patent No. 8,076,275. These complexes are prepared by a process comprising reacting an acidic molybdenum compound with an alkyl or alkenyl succinimide of a polyamine of the structure (3), (4) or mixtures thereof:

wherein R is C ₂₄ To C ₃₅₀ (e.g., C) ₇₀ To C ₁₂₈ ) An alkyl or alkenyl group; r' is a linear or branched alkylene group having 2 to 3 carbon atoms; x is 1 to 11; and y is 1 to 10.

The molybdenum compound used to prepare the molybdenum-succinimide complex is an acidic molybdenum compound or a salt of an acidic molybdenum compound. By "acidic" is meant that the molybdenum compound will react with a basic nitrogen compound as measured according to ASTM D664 or D2896. Generally, acid molybdationThe compound is hexavalent. Representative examples of suitable molybdenum compounds include molybdenum trioxide, molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates and other molybdenum salts such as hydrogen salts (e.g., sodium hydrogen molybdate), moOCl ₄ 、MoO ₂ Br _2、 Mo ₂ O ₃ Cl ₆ And the like.

Succinimides that can be used to prepare molybdenum-succinimide complexes are disclosed in a number of references and are well known in the art. Some basic types of succinimides and related materials covered by the term "succinimide" in the art are taught in U.S. Pat. Nos. 3,172,892, 3,219,666, and 3,272,746. The term "succinimide" is understood in the art to include many of the amide, imide, and amidine species that may also be formed. However, the predominant product is succinimide, which term is generally understood to refer to the product of the reaction of an alkyl or alkenyl substituted succinic acid or anhydride with a nitrogen-containing compound. The preferred succinimide is one prepared by reacting polyisobutenyl succinic anhydride of about 70 to 128 carbon atoms with a polyalkylene polyamine selected from the group consisting of triethylene tetramine, tetraethylene pentamine and mixtures thereof.

In one embodiment, the molybdenum-containing compound contains no sulfur.

The molybdenum-succinimide complex may be post-treated with a sulfur source at a suitable pressure and temperature not exceeding 120 ℃ to provide a sulfurized molybdenum-succinimide complex. The vulcanization step may be performed for about 0.5 to 5 hours (e.g., 0.5 to 2 hours). Suitable sulfur sources include elemental sulfur, hydrogen sulfide, phosphorus pentasulfide, formula R ₂ S _x Wherein R is a hydrocarbon group (e.g., C) ₁ To C ₁₀ Alkyl) and x is at least 3), C ₁ To C ₁₀ Mercaptans, inorganic sulfides and polysulfides, thioacetamides and thioureas.

The molybdenum-containing compound is used in an amount to provide molybdenum to the lubricating oil composition in an amount of from 50ppm to 1200ppm, from 50ppm to 1000ppm, from 50ppm to 800ppm, from 50ppm to 600ppm, from 50ppm to 400ppm, or from 50ppm to 200 ppm.

In some embodiments, the lubricating oil composition is substantially free of molybdenum-containing compounds.

The molybdenum-containing compound can promote the formation of a molybdenum-containing lubricating oil film on the metal surfaces of the engine during use of the lubricating oil composition in the engine.

According to an exemplary embodiment, the lubricating oil composition comprises MoDTC in an amount ranging from 0.6wt.% to 0.8wt.%, based on the total weight of the lubricating composition.

Corrosion inhibitor

Corrosion inhibitors protect lubricated metal surfaces from chemical attack by water or other contaminants. Suitable corrosion inhibitors include polyoxyalkylene polyols and esters thereof, polyoxyalkylene phenols, thiadiazoles and anionic alkyl sulfonic acids.

Pour point depressant

Pour point depressants lower the minimum temperature at which the fluid will flow or can be poured. Suitable pour point depressants include C8 to C18 dialkyl fumarate/vinyl acetate copolymers, polyalkylmethacrylates, and the like.

Suds suppressor

Suds suppressors retard the formation of stable suds. Examples of suitable suds suppressors include silicones, polyacrylates, and the like.

Process for preparing lubricating oil compositions

The lubricating oil compositions disclosed herein can be prepared by any method known to those of ordinary skill in the art for preparing lubricating oils. The viscosity modifier and other additives may be added to the base oil separately or simultaneously. In some embodiments, the additives are added separately to the base oil in one or more additions, and may be added in any order. In other embodiments, the additives are added simultaneously to the base oil, optionally in the form of an additive concentrate. According to another embodiment, some of the additives are added separately and some of the additives are added in the form of an additive concentrate. In some embodiments, the dissolution of the additive in the base oil may be aided by heating the mixture to a temperature of from about 25 ℃ to about 200 ℃, from about 50 ℃ to about 150 ℃, or from about 75 ℃ to about 125 ℃.

Any mixing or dispersing device known to those of ordinary skill in the art may be used to blend, mix, or dissolve the ingredients used to form the lubricating oil composition. Blending, mixing, or dissolving may be performed with a blender, stirrer, disperser, mixer (e.g., planetary mixer and double planetary mixer), homogenizer (e.g., gaulin homogenizer and Rannie homogenizer), mill (e.g., colloid mill, ball mill, and sand mill), or any other mixing or dispersing device known in the art.

Use of lubricating oil compositions

The lubricating oil compositions disclosed herein may be suitable for use as engine oils (engine oils or crankcase oils) in spark-ignited internal combustion engines. The lubricating oil composition is preferably used in engines or crankcases requiring a viscosity grade of SAE 0W-20, 0W-16 or 0W-12. For example, the lubricating oil composition may be used to lubricate an engine including a valvetrain system including roller driven rocker arms.

The following invention examples are provided to illustrate embodiments of the invention, but are not intended to limit the invention to the specific embodiments described. All parts and percentages are by weight unless indicated to the contrary. All values are approximate. When numerical ranges are given, it is understood that embodiments outside the stated ranges are still within the scope of the invention. Specific details described in each embodiment should not be construed as essential features of the invention.

Examples

The benchmark formulations for all inventive and comparative examples were prepared by blending together the following ingredients provided in wt.% based on the total weight of the lubricating oil composition:

(a) 1wt.% of a borated succinimide,

(b) 3wt.% of a succinimide treated with Ethylene Carbonate (EC),

(c) 0.34wt.% of a secondary ZnDTP,

(d) 0.72wt.% primary ZnDTP,

(e) 0.5wt.% of calcium LOB sulfonate,

(f) 0.77wt.% of calcium HOB salicylate,

(g) 0.5wt.% of MOB calcium salicylate,

(h) 2wt.% of an amine antioxidant, wherein the amine antioxidant is,

(i) 0.004wt.% of suds suppressor, and

(h) And (4) diluting the oil.

The wt.% of ingredients (a) to (h) includes any diluents and/or solvents that may be present and are therefore not an active basis.

All inventive and comparative examples were prepared by finish treating a base formulation in Yubase 4+ as a group III base oil with 0.7wt.% molybdenum dithiocarbamate (MoDTC) providing 700ppm molybdenum and the viscosity modifiers of tables 2 and 3 (comb PMA and/or OCP) to obtain lubricating oil compositions having a viscosity grade SAE 0W-20. Inventive example compositions are provided in table 2, while comparative example compositions are provided in table 3.

TABLE 2 examples of the invention

TABLE 3 comparative examples

¹ PMA(

3-201) is a compound containing 19wt.% of a non-dispersant comb polymethacrylate with a Mw of 420,000g/mol and a Mw/Mn of 5.92.

² OCP1 is a concentrate containing 10wt.% of a non-dispersant ethylene-propylene copolymer having an ethylene content of 57wt.%, an Mw of about 100,000, an Mn of about 40,000, and an SSI of 24.

³ OCP 2 is a concentrate containing 8.75wt.% of a non-dispersant ethylene-propylene copolymer having an ethylene content of 57wt.%, an Mw of 112,000, an Mn of 49,000, and an SSI of 35.

⁴ OCP 3 is a concentrate containing 8.8wt.% of a non-dispersant ethylene-propylene copolymer having an ethylene content of 49wt.%, an Mw of 146,000, an Mn of 84,000, and an SSI of 50.

Fuel economy testing in a Toyota 2ZR-FE powered engine

The lubricating oil compositions of examples 1 to 9 of the present invention and comparative examples 1 to 4 were tested for fuel economy in a gasoline powered engine test. The engine is a Toyota 2ZR-FE1.8L in-line type 4-cylinder device. A torque meter is positioned between the electric motor and the crankshaft of the engine and measures a percentage change in torque between the reference lubricating oil composition and the candidate lubricating oil composition. The percent (%) change in torque was measured at oil temperatures of 60 ℃,80 ℃ and 100 ℃ and engine speeds of 400rpm, 550rpm, 750rpm, 1000rpm, 1500rpm and 2000 rpm. The lower the percentage of torque change (i.e., more negative), the better the fuel economy. The configuration of the power engine friction torque test and its test conditions are further described in SAE paper 2013-01-2606. Table 4 provides the average% torque change at oil temperatures of 60 ℃,80 ℃ and 100 ℃ for the compositions of the examples of the present invention, and table 5 provides the average% torque change at oil temperatures of 60 ℃,80 ℃ and 100 ℃ for the compositions of the comparative examples.

TABLE 4 Power Engine Friction Torque-embodiments of the invention

TABLE 5 Power Engine Friction Torque-comparative example

Claims

1. A lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

b) Non-dispersant comb Polymethacrylate (PMA); and

c) A non-dispersant ethylene-based olefin copolymer,

the kinematic viscosity of the lubricating oil composition at 100 ℃ is less than 9.3mm ² /s。

2. The lubricating oil composition of claim 1, wherein the weight average molecular weight (Mw) of the non-dispersant comb PMA is 390,000g/mol to 460,000g/mol.

3. The lubricating oil composition of claim 1, wherein the Shear Stability Index (SSI) of the non-dispersant comb PMA is from 0.3 to 0.8.

4. The lubricating oil composition of claim 1, wherein the non-dispersant comb PMA is present in an amount of 0.4 to 2.0wt.%, based on the total weight of the lubricating oil composition.

5. The lubricating oil composition of claim 1, wherein the non-dispersant ethylene-based olefin copolymer has a weight average molecular weight (Mw) of from 90,000g/mol to 160,000g/mol.

6. The lubricating oil composition of claim 1, wherein the non-dispersant ethylene-based olefin copolymer has a Shear Stability Index (SSI) of from 10 to 70.

7. The lubricating oil composition of claim 1, wherein the non-dispersant ethylene-based olefin copolymer is present in an amount of 0.08wt.% to 0.4wt.%, based on the total weight of the lubricating oil composition.

8. The lubricating oil composition of claim 1, wherein the non-dispersant ethylene-based olefin copolymer has a total ethylene content of 45wt.% to 60wt.%, based on the total weight of the non-dispersant ethylene-based olefin copolymer.

9. The lubricating oil composition of claim 1, wherein the non-dispersant ethylene-based olefin copolymer is an ethylene propylene copolymer.

10. The lubricating oil composition of claim 1, wherein the non-dispersant comb PMA is present in an amount of 0.76 to 1.33wt.%, and the non-dispersant ethylene-based olefin copolymer is present in an amount of 0.08 to 0.4wt.%, based on the total weight of the lubricating oil composition.

11. The lubricating oil composition of claim 1, wherein the non-dispersant comb PMA and the non-dispersant ethylene-based olefin copolymer are present in a total amount of 0.4wt.% to 4wt.%, based on the total weight of the lubricating oil composition.

12. The lubricating oil composition of claim 1, wherein the oil of lubricating viscosity is an API group III base oil.

13. The lubricating oil composition of claim 1, wherein the composition further comprises a molybdenum compound.

14. The lubricating oil composition of claim 13, wherein the molybdenum compound is molybdenum dithiocarbamate (MoDTC).

15. The lubricating oil composition of claim 13, wherein the molybdenum compound provides the lubricating oil composition with a molybdenum content in the range of 50ppm to 1200 ppm.

16. The lubricating oil composition of claim 1, wherein the lubricating oil composition has a viscosity grade of SAE 0W-20, 0W-16, or 0W-12.

17. The lubricating oil composition of claim 1, wherein the lubricating oil composition has a High Temperature High Shear (HTHS) viscosity at 150 ℃ of from 2.55cP to less than 2.9cP.

18. The lubricating oil composition of claim 1, wherein the viscosity index of the lubricating oil composition is from 200 to 240.

19. A method for reducing wear in an internal combustion engine, the method comprising using a kinematic viscosity at 100 ℃ of less than 9.3mm ² Lubricating oil composition for lubricating said engine, said lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

b) Non-dispersant comb Polymethacrylate (PMA); and

c) The non-dispersant ethylene-based olefin copolymer.

20. The method of claim 19, wherein the engine comprises a roller driven rocker arm.

21. A lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

22. A method for reducing wear in an internal combustion engine, the method comprising lubricating the engine with a lubricating oil composition comprising:

a) A major amount of an oil of lubricating viscosity;

b) A non-dispersant comb Polymethacrylate (PMA) in an amount of from 0.4wt.% to 1.9wt.%, based on the total weight of the lubricating oil composition; and

23. The method of claim 22, wherein the engine comprises a roller driven rocker arm.