JP7315587B2 - Lubricant for wet clutch system - Google Patents

Description

The present invention relates generally to lubricating oil compositions useful for industrial machinery, particularly transportation, construction and agricultural machinery.

BACKGROUND OF THE INVENTION Automatic transmission lubricating oils, called automatic transmission fluids, are conventionally used to assist in the smooth operation of automatic transmissions in automobiles, trucks, construction equipment and other vehicles. An automatic transmission includes a torque converter, gear mechanism, wet clutch and hydraulic system.

It is widely known that lubricant additives affect the friction properties of wet clutches and steel plates. Additive effects are caused by both physical and chemical absorption of additives in clutch materials such as cellulose, aramid (natural and synthetic) fibers, silica and steel plate surfaces.

Various diesel engine oils are widely used for internal combustion engines, in Asia, especially in Japan, not only for heavy-duty diesel engine systems for automobiles, but also for diesel engine systems of construction machinery. Some construction equipment is equipped with wet clutch systems not only in transmissions, but also in many systems for controlling steering, parking brakes, and travel and power actuation torques. The (static) friction of a wet clutch between the clutch material in the lubricating fluid and the steel is very important for the efficient transmission of engine power. Additionally, the static friction coefficient of a wet clutch depends on the torque capacity of the wet clutch. Various engine oils are widely used for transmission and hydraulic systems in construction equipment and their wet clutch systems. It is important to maintain a higher (static) coefficient of friction of wet clutches to provide safe operation and, likewise, to efficiently transmit power for construction machinery. If the lubricant results in poor friction performance, there will be power loss, slow response of machine operation which can have a negative impact on safety when the machine is running, or objectionable vibration with loud noise from wet clutch lockup in the transmission.

The present invention finds a solution for maintaining a higher static coefficient of friction of wet clutches, which is important not only in construction equipment, but also in transmissions and motorcycle lubricants with wet clutches.

According to one embodiment of the invention, the following ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
including
Phosphorus content is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
A lubricating oil composition having a Ca to Mg mass ratio of 1:2 to 4:1 and lubricating the crankcase and at least one of a wet clutch, brake, torque converter, gear system, hydrostatic transmission and hydraulic system of a vehicle internal combustion engine is provided.

According to another embodiment of the invention, a method for maintaining friction in a vehicle, comprising:
Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
lubricating the vehicle with a lubricating oil composition comprising
The phosphorus content of the lubricating oil composition is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
A method is provided wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and wherein the lubricating oil composition lubricates the crankcase and at least one of a wet clutch, brake, torque converter, gear system, hydrostatic transmission and hydraulic system of an internal combustion engine of the vehicle.
Note that the following [1] to [12] are all aspects or aspects of the present invention.
[1]
Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
including
Phosphorus content is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
the mass ratio of Ca to Mg is 1:2 to 4:1, and
A lubricating oil composition for lubricating the crankcase and at least one of a wet clutch, brake, torque converter, gear system, hydrostatic transmission and hydraulic system of a vehicle internal combustion engine.
[2]
The lubricating oil composition according to [1], wherein calcium derived from the calcium-containing detergent is present in at least 1000 ppm of the lubricating oil composition.
[3]
The lubricating oil composition according to [1], wherein the total base number (TBN) of the lubricating oil composition is 8 mgKOH/g to 16 mgKOH/g.
[4]
The sulfated ash content specified according to ASTM D874 is about 0.80 wt. % to about 1.60 wt. %, the lubricating oil composition according to [1].
[5]
The lubricating oil composition according to [1], wherein the vehicle is an industrial machine, automobile, truck or other vehicle.
[6]
The lubricating oil composition according to [5], wherein the industrial machine is transport machine, construction machine or agricultural machine.
[7]
The lubricating oil composition according to [1], wherein the vehicle is equipped with an automatic transmission or a continuously variable transmission.
[8]
A method for maintaining friction in a vehicle, comprising:
Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
lubricating the vehicle with a lubricating oil composition comprising
The phosphorus content of the lubricating oil composition is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
the mass ratio of Ca to Mg is 1:2 to 4:1, and
The above method, wherein the lubricating oil composition lubricates the crankcase and at least one of a wet clutch, brakes, torque converter, gear system, hydrostatic transmission and hydraulic system of an internal combustion engine of the vehicle.
[9]
The method of [8], wherein calcium derived from the calcium-containing detergent is present at least 1000 ppm of the lubricating oil composition.
[10]
The method of [8], wherein the vehicle is an industrial machine, automobile, truck or other vehicle.
[11]
The lubricating oil composition according to [10], wherein the industrial machine is transport machine, construction machine or agricultural machine.
[12]
The method of [8], wherein the vehicle comprises an automatic transmission or a continuously variable transmission.

To facilitate understanding of the subject matter disclosed herein, some terms, abbreviations or other abbreviations as used herein are defined below. It is understood that any term, abbreviation or shorthand not defined has the ordinary meaning used by one of ordinary skill in the art at the time this application was submitted.

DEFINITIONS As used herein, the following terms and expressions, if and when used, have the meanings indicated below.

By "major amount" is meant greater than 50% by weight of the composition.

"Minor amount" means less than 50% by weight of the composition, provided that this is expressed with respect to the specified additive when considered as an active ingredient of the additive(s) and with respect to the total mass of all additives present in the composition.

"Active ingredient" or "active substance" refers to additive materials that are not diluents or solvents.

All percentages reported are weight percent based on active ingredient (ie, ignoring carrier or diluent oil) unless otherwise specified.

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

High temperature high shear (HTHS) viscosity at 150° C. was determined according to ASTM D4683.

Kinematic viscosity (KV ₁₀₀ ) at 100° C. was determined according to ASTM D445.

Metal - The term "metal" refers to alkali metals, alkaline earth metals, or mixtures thereof.

Throughout the specification and claims the expressions oil-soluble or oil-dispersible are used. By oil soluble or oil dispersible is meant that the amount required to provide the desired level of activity or performance can be incorporated by being dissolved, dispersed or suspended in an oil of lubricating viscosity. Generally, this means that at least about 0.001% by weight of material can be incorporated into the lubricating oil composition. For further discussion of the terms oil-soluble and oil-dispersible, particularly the term “stable dispersible,” see U.S. Pat. No. 4,320,019, which is specifically incorporated herein by reference for relevant teachings in this regard.

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

The term "total base number" or "TBN" as used herein refers to the amount of base in a 1 gram sample equivalent to milligrams of KOH. Thus, a higher TBN number reflects a more alkaline product and therefore a higher alkalinity. TBN was determined using the ASTM D2896 test.

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

Nitrogen content was determined according to ASTM D4629.

All ASTM standards referred to herein are current as of the filing date of this application.

All percentages are in weight percent unless otherwise specified.

While this disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are described in detail herein. 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 rather that the invention will encompass all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.

Note that not all of the activities recited in the general description or examples are required, some of the specific activities may not be required, and one or more additional activities may be accomplished in addition to the disclosed activities. Still further, the order in which activities are listed is not necessarily the order in which they are accomplished.

Various advantages, other advantages, and solutions to problems are described herein with regard to specific embodiments. However, none of these advantages, advantages, solutions to problems, and any feature or features that may give rise to or make any advantage, advantage, or solution to any advantage, be construed as being an important feature, required feature, or essential feature of any or all claims.

Clarifications and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of these various embodiments.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” or any other variation thereof are intended to encompass nonexclusive inclusion. For example, a process, method, article or apparatus that includes a set of recited features is not necessarily limited to only such features, but may include other features not expressly listed or that are unique to such process, method, article or apparatus. Further, unless expressly stated to the contrary, "or" (or or or) denotes an inclusive or and not an exclusive or. For example, condition A or condition B is satisfied by any one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

Use of "a" or "an" are employed 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 description should be read to include one or at least one, and the singular also includes the plural, and vice versa, the plural also includes one, unless it is clear that the description is meant to the contrary. The term "averaged," when denoting a value, is intended to mean the mean, geometric mean, or median. Group numbers corresponding to columns in the Periodic Table of the Elements use the "new notation" convention as found in the CRC Handbook of Chemistry and Physics, 81st Edition (2000-2001).

Unless otherwise defined, 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. Unless described herein, many details regarding specific materials and processing practices are conventional and may be found in textbooks and other sources in the lubricants, as well as oil and gas industries.

The specification and examples are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of the formulations, compositions, devices and systems in which the structures or methods described herein are used. Various separate embodiments may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of only one embodiment, may also be provided separately or in any subcombination. Further, references to values stated in ranges include each and every value subsumed within that range. Many other embodiments may become apparent to those skilled in the art only after reading and understanding this specification. Other embodiments may be used or derived from the present disclosure, such that structural substitutions, logical substitutions, or other modifications may be made without departing from the scope of the present disclosure. Accordingly, the present disclosure is to be regarded as illustrative rather than restrictive.

According to one embodiment of the invention, the following ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
including
Phosphorus content is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
A lubricating oil composition having a Ca to Mg mass ratio of 1:2 to 4:1 and lubricating the crankcase and at least one of a wet clutch, brake, torque converter, gear system, hydrostatic transmission and hydraulic system of a vehicle internal combustion engine is provided.

In one embodiment of the invention, the vehicle is an industrial machine, automobile, truck or other vehicle. In another embodiment, the industrial machine is a transportation machine, a construction machine, or an agricultural machine.

In one embodiment, the transport machine is a bus or truck with a diesel engine and hydraulic system.

In one embodiment, a construction machine includes a diesel engine, a hydrostatic transmission (HST), a powershift transmission with a wet clutch, and a hydraulic system.

In one embodiment, an agricultural machine includes a diesel engine, a hydrostatic transmission (HST), a powershift transmission with a wet clutch, and a hydraulic system.

In another embodiment, the vehicle includes an automatic transmission or a continuously variable transmission.

In another embodiment, a method for maintaining friction in a vehicle comprising:
Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
lubricating the vehicle with a lubricating oil composition comprising
The phosphorus content of the lubricating oil composition is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
A method is provided wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and wherein the lubricating oil composition lubricates the crankcase and at least one of a wet clutch, brake, torque converter, gear system, hydrostatic transmission and hydraulic system of an internal combustion engine of the vehicle.

Oils of Lubricating Viscosity/Base Oil Components Oils of lubricating viscosity, sometimes (referred to as "base stocks" or "base oils"), are the major liquid constituents of lubricants, into which additives and optionally other oils are blended, e.g., to produce the final lubricant (or lubricant composition). Base oils are useful for making a variety of concentrates, as well as for making lubricating oil compositions from such concentrates, natural and synthetic lubricating oils, and It may be selected from those combinations.

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

Synthetic lubricating oils include hydrocarbon oils such as polymeric and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylenes, poly(1-hexene), poly(1-octene), poly(1-decene), etc.; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)benzenes); polyphenols (e.g., biphenyl-based, terphenyl-based, alkylated polyphenols). ); and alkylated diphenyl ethers and alkylated diphenyl sulfides, and derivatives, analogs and homologues thereof.

Another suitable class of synthetic lubricating oils includes dicarboxylic acids (e.g., malonic, alkylmalonic, alkenylmalonic, succinic, alkyl and alkenylsuccinic acids, maleic, fumaric, azelaic, suberic, sebacic, adipic, linoleic dimer, phthalic) and various alcohols (e.g., butyl, hexyl, dodecyl, 2-ethylhexyl, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, and 1 mole of sebacic acid to 2 moles of tetraethylene glycol and 2 Complex esters formed by reaction with molar 2-ethylhexanoic acid are included.

Esters useful as synthetic oils also include esters made from C ₅ -C ₁₂ 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 synthetic hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas containing _H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing to be useful as base oils. For example, these hydrocarbons may be hydroisomerized, hydrocracked and hydroisomerized, dewaxed, or hydroisomerized and dewaxed using processes known to those skilled in the art.

Unrefined, refined and re-refined oils can be used in the lubricating oil compositions of this invention. Unrefined oils are oils 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 that they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art, such as distillation, solvent extraction, acid or base extraction, filtration and percolation. Re-refined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils that have been already used in service. Such re-refined oils, also known as reclaimed or reprocessed oils, are often further processed by various techniques for approval of used additives and oil breakdown products.

Thus, the base oils that may be used to make the lubricating oil compositions of the present invention may be selected from any of the base oils in Groups I through V as specified in the American Petroleum Institute (API) Base Oil Compatibility Guidelines (API Publication 1509). Such base oil groups are summarized in Table 1 below.

Base oils suitable for use herein are any of the classes corresponding to API Group I, Group II, Group III, Group IV and Group V oils and combinations thereof.

The base oil constitutes the main component of the lubricating oil composition of the present invention and is 50 wt. % to 99 wt. % (eg, 70 wt.% to 95 wt.%, or 85 wt.% to 95 wt.%).

Generally, the sulfur level in the lubricating oil composition of the present invention is about 0.7 wt. % or less: for example about 0.01 wt. % to about 0.70 wt. %, 0.01 wt. % to 0.6 wt. %, 0.01 wt. % to 0.5 wt. %, 0.01 wt. % to 0.4 wt. %, 0.01 wt. % to 0.3 wt. %, 0.01 wt. % to 0.2 wt. %, 0.01 wt. % to 0.10 wt. % sulfur level. In one embodiment, the sulfur level in the lubricating oil composition of the present invention is about 0.60 wt. % or less, about 0.50 wt. % or less, about 0.40 wt. % or less, about 0.35 wt. % or less, about 0.34 wt. % or less, about 0.33 wt. % or less, about 0.32 wt. % or less, about 0.31 wt. % or less, about 0.30 wt. % or less.

In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.15 wt. % or less. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.06 wt. % to about 0.15 wt. %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.14 wt. % or less: for example about 0.06 wt. % to about 0.14 wt. Phosphorus level in %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.13 wt. % or less: for example about 0.06 wt. % to about 0.13 wt. Phosphorus level in %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.12 wt. % or less: for example about 0.06 wt. % to about 0.12 wt. Phosphorus level in %.

In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 1.60 wt. % or less: for example, about 0.80 wt. % to about 1.60 wt. % sulfated ash level. In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 1.50 wt. % or less: for example, about 0.80 wt. % to about 1.50 wt. % sulfated ash level. In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 1.40 wt. % or less: for example, about 0.80 wt. % to about 1.40 wt. % sulfated ash level.

Suitably, the lubricating oil composition of the present invention may have a total base number (TBN) of 8 mg KOH/g to 16 mg KOH/g. In some embodiments, the lubricating oil composition may have a Total Base Number (TBN) of 10 mg KOH/g to 16 mg KOH/g, 10 mg KOH/g to 14 mg KOH/g, 10 mg KOH/g to 13 mg KOH/g, or 10 mg KOH/g to 12 mg KOH/g.

In some embodiments, for example, the desired grade of oil is of an SAE viscosity grade such as 0W-30, 0W-40, 5W-30, 10W-30, 10W-40, 10W-50, 15W-30, 15W-40, 20W-50, 30, 40.

Detergent Mixture The detergent mixture comprises at least one calcium-containing detergent and at least one magnesium-containing detergent.

Typical detergents are anionic materials containing a long chain hydrophobic portion of the molecule and a smaller anionic or oil-repellent hydrophilic portion of the molecule. The anionic portion of detergents is typically derived from organic acids such as sulfuric acid, carboxylic acid, phosphorous acid, phenol, or mixtures thereof. Counterions are typically alkaline earth metals or alkali metals.

Salts containing substantially stoichiometric amounts of metals are described as neutral salts and have a total base number (TBN) of 0-80 mg KOH/g. Many compositions are overbased because they contain large amounts of metal base, which is achieved by reacting excess metal compounds (e.g., metal hydroxides or metal oxides) with acid gases (e.g., carbon dioxide). Useful detergents can be neutral, lightly overbased, or highly overbased.

It is desirable that at least some of the detergents used in the detergent mixture be overbased. Overbased detergents help neutralize and trap in the oil acidic impurities produced by the combustion process. Typically, overbased materials have a ratio of metal ions to anionic moieties of the detergent of 1.05:1 to 50:1 (eg, 4:1 to 25:1) on an equivalents basis. The resulting detergent is an overbased detergent with a TBN typically of 150 mg KOH/g or greater (eg, 250 mg KOH/g to 450 mg KOH/g or greater). Mixtures of detergents with different TBNs can be used.

In some embodiments, the overbased detergent may be low overbased, eg, an overbased salt having a TBN of less than 100 based on actives. In one embodiment, the TBN of the low overbased salt may be from about 30 to about 100. In another embodiment, the TBN of the low overbased salt may be from about 30 to about 80. In some embodiments, the overbased detergent can be medium overbased, eg, an overbased salt having a TBN of about 100 to about 250. In one embodiment, the moderately overbased salt may have a TBN of about 100 to about 200. In another embodiment, the moderately overbased salt may have a TBN of about 125 to about 175. In some embodiments, the overbased detergent may be highly overbased, eg, overbased salts with a TBN greater than 250. In one embodiment, the TBN of the highly overbased salt may be from about 250 to about 800 on an actives basis.

Suitable detergents include metal salts of sulfonates, phenates, carboxylates, phosphates and salicylates.

Sulfonates may be prepared from sulfonic acids, typically obtained by sulfonating alkyl-substituted aromatic hydrocarbons such as those obtained from petroleum fractionation or obtained by alkylation of aromatic hydrocarbons. Examples included those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl or their halogen derivatives. This alkylation may be carried out in the presence of a catalyst using an alkylating agent having from about 3 to more than 70 carbon atoms. Alkaryl sulfonates typically contain from about 9 to 80 or more carbon atoms (eg, from about 16 to 60 carbon atoms) per alkyl-substituted aromatic moiety.

Phenates can be prepared by reacting an alkaline earth metal hydroxide or oxide (eg, CaO, Ca(OH) ₂ , MgO or Mg(OH) ₂ ) with an alkylphenol or sulfurized alkylphenol. Useful alkyl groups include straight or branched chain C ₁ -C ₃₀ (eg, C ₄ -C ₂₀ ) alkyl groups, or mixtures thereof. Examples of suitable phenols include isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecylphenol, and the like. It should be noted that the starting alkylphenol may contain two or more alkyl substituents, each independently linear or branched. When non-sulfurized alkylphenols are used, sulfurized products may be obtained by methods well known in the art. These methods include heating a mixture of an alkylphenol and a sulfurizing agent (e.g., elemental sulfur, sulfur halides such as sulfur dichloride, etc.) and then reacting the sulfurized phenol with an alkaline earth metal base.

Salicylates may be prepared by reacting a basic metal compound with at least one carboxylic acid and removing water from the reaction product. Detergents made from salicylic acid are one class of detergents prepared from carboxylic acids. Useful salicylates include long chain alkyl salicylates.

Hydrocarbyl-substituted salicylic acids may be prepared from various phenols by the Kolbe reaction (see US Pat. No. 3,595,791). Metal salts of hydrocarbyl-substituted salicylic acids may be prepared by metathesis of metal salts in polar solvents such as water or alcohols.

Alkaline earth metal phosphates are also used as detergents and are known in the art.

Preferred calcium-containing detergents include calcium sulfonates, calcium phenates and calcium salicylates, especially calcium sulfonates, calcium salicylates, and mixtures thereof.

Calcium Detergents In one embodiment, calcium-containing detergents include calcium sulfonates, calcium phenates and calcium salicylates.

the calcium-containing detergent is at least 1000 ppm, at least 1050 ppm, at least 1100 ppm, at least 1150 ppm, at least 1200 ppm, at least 1250 ppm, at least 1300 ppm, at least 1350 ppm, at least 1400 ppm, at least 1450 ppm, at least 1500 ppm, at least 1550 ppm, at least 1600 ppm, at least 1650 ppm, at least 1700 ppm, at least 1750 ppm; Amounts that provide at least 1800 ppm, at least 1850 ppm, at least 1900 ppm, at least 1950 ppm, at least 2000 ppm of calcium in the lubricating oil composition may be used. In one embodiment, the calcium content is 4000 ppm or less, 3500 ppm or less, 3000 ppm or less, by weight of calcium to lubricating oil composition.

In some embodiments, the calcium-containing detergent can be a high overbased, moderately overbased or low overbased detergent.

Magnesium Detergents Preferred magnesium-containing detergents include magnesium sulfonates, magnesium phenates and magnesium salicylates, especially magnesium sulfonates.

The magnesium-containing detergent is at least 800 ppm, at least 850 ppm, at least 900 ppm, at least 950 ppm, at least 1000 ppm, at least 1050 ppm, at least 1100 ppm, at least 1150 ppm, at least 1200 ppm, at least 1250 ppm, at least 1300 ppm, at least 1350 ppm, at least 1400 ppm, at least 1450 ppm, at least 1500 ppm, at least 1550 ppm, at least 160 ppm It may be used in an amount to provide 0 ppm, at least 1650 ppm, at least 1700 ppm, at least 1750 ppm, at least 1800 ppm, at least 1850 ppm, at least 1900 ppm, at least 1950 ppm, at least 2000 ppm magnesium in the lubricating oil composition. In one embodiment, the magnesium content is no greater than 4000 ppm, no greater than 3500 ppm, no greater than 3000 ppm, no greater than 2500 ppm by weight of magnesium in the lubricating oil composition. In one embodiment, the magnesium content is 800 ppm to 2500 ppm, 900 ppm to 2300 ppm, 1100 ppm to 2300 ppm, 1300 ppm to 2300 ppm, 1500 ppm to 2300 ppm by weight of magnesium in the lubricating oil composition.

In some embodiments, magnesium-containing detergents can be high overbased, moderately overbased, or low overbased detergents. In one embodiment, the mass ratio of calcium to magnesium in the lubricating oil composition is from 0.5:1 to 4:1. In other embodiments, the mass ratio of calcium to magnesium in the lubricating oil composition is 0.6:1 to 3.5:1, 0.6:1 to 3.0:1, 0.6:1 to 2.5:1, 0.6:1 to 2.0:1, 0.6:1 to 1.7:1, 0.6:1 to 1.5:1, 0.6:1 to 1.3:1.

Nitrogen-Containing Dispersants Dispersants keep various materials in suspension resulting from oxidation during engine operation that are insoluble in oil, thus preventing sludge flocculation and precipitation or deposition on metal parts surfaces. Dispersants useful herein include nitrogen-containing, ashless (metal-free) dispersants known to be effective for reducing deposit formation when used in gasoline and diesel engines.

Suitable dispersants include hydrocarbyl succinimides, hydrocarbyl succinamides, mixed esters/amides of hydrocarbyl-substituted succinic acids, hydroxy esters of hydrocarbyl-substituted succinic acids, and Mannich condensation products of hydrocarbyl-substituted phenols, formaldehydes and polyamines. Condensation products of polyamines and hydrocarbyl-substituted phenyl acids are also suitable. Mixtures of these dispersants can also be used.

Basic nitrogen-containing ashless dispersants are well known lubricating oil additives, and various methods for their preparation have been extensively described in the patent literature. Preferred dispersants are alkenylsuccinimides and alkenylsuccinamides in which the alkenyl substituent is preferably a long chain of greater than 40 carbon atoms. These materials are readily made by reacting a hydrocarbyl-substituted dicarboxylic acid material with a molecule containing an amine functional group. Examples of suitable amines include polyamines such as polyalkylenepolyamines, hydroxy-substituted polyamines and polyoxyalkylenepolyamines.

Particularly preferred ashless dispersants are polyisobutenylsuccinic anhydrides and polyalkylenepolyamines (e.g., polyethylenepolyamines of the formula:
_NH2 ( _{CH2CH2NH ) zH}
(Wherein, z is 1 to 11)
etc.) and polyisobutenyl succinimides. The polyisobutenyl group is derived from polyisobutene and preferably has a number average molecular weight (Mn) in the range of 700 Daltons to 3000 Daltons (eg, 900 Daltons to 2500 Daltons). For example, a polyisobutenyl succinimide can be a bissuccinimide derived from a polyisobutenyl group with an Mn between 900 and 2500 daltons.

As is known in the art, dispersants may be post-treated (eg, with boronizing agents or cyclic carbonates).

Nitrogen-containing ashless (metal-free) dispersants are basic and contribute to the TBN of the lubricating oil composition to which they are added without introducing additional sulfated ash.

The dispersant may be present in an amount to provide less than 600 ppm nitrogen to the lubricating oil composition at a weight ratio of nitrogen to lubricating oil composition of less than 550 ppm, less than 500 ppm, less than 450 ppm, less than 400 ppm nitrogen.

Other Lubricating Oil Additives In addition to the additive compounds described herein, the lubricating oil composition may contain additional lubricating oil additives.

The lubricating oil compositions of this disclosure may also contain various other conventional additives that can impart or improve any desired properties of the lubricating oil composition in which they are dispersed or dissolved. Any additive known to a person of ordinary skill in the art may be used in the lubricating oil compositions disclosed herein. Some suitable additives are described in Mortier et al., "Chemistry and Technology of Lubricants" (2nd ed., London, Springer, 1996); 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 can be blended with antioxidants, antiwear agents, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, defoamers, cosolvents, corrosion inhibitors, ashless dispersants, multifunctional agents, pigments, extreme pressure additives, etc., and mixtures thereof. A variety of these additives are known and commercially available. These additives, or their analogous compounds, can be used for the preparation of the lubricating oil compositions of this disclosure by conventional blending procedures.

The lubricating oil compositions of the present invention may contain one or more antiwear agents that can reduce friction and excessive wear. Any antiwear agent known by those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable antiwear agents include zinc dithiophosphates, metal salts of dithiophosphates (such as Pb, Sb and Mo salts), metal salts of dithiocarbamates (such as Zn, Pb, Sb and Mo salts), metal salts of fatty acids (such as Zn, Pb and Sb salts), boron compounds, phosphate esters, phosphite esters, phosphate or thiophosphate amine salts, di Included are reaction products of cyclopentadiene and various thiophosphoric acids, and combinations thereof. The amount of antiwear agent is about 0.01 wt. % to about 5 wt. % to about 0.05 wt. % to about 3 wt. %, or about 0.1 wt. % to about 1 wt. % may vary.

In certain embodiments, the antiwear agent is or comprises a dihydrocarbyl dithiophosphate metal salt, such as a zinc dialkyldithiophosphate compound, such as a zinc dialkyldithiophosphate compound. The metal of the dihydrocarbyl dithiophosphate metal salt may be an alkali metal or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or copper. In some 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. In a further embodiment, an alkyl group is linear or branched.

The amount of dihydrocarbyl dithiophosphate metal salts, including zinc dialkyldithiophosphate salts, in the lubricating oil compositions disclosed herein is measured by its phosphorus content. In some embodiments, the phosphorus content of the lubricating oil composition is as disclosed herein.

The lubricating oil composition of the present invention preferably contains 0.01 wt. % to 5 wt. %, preferably 0.1 wt. % to 3 wt. %. Antioxidants can be hindered phenol type antioxidants or diarylamine type antioxidants. Diarylamine-type antioxidants are advantageous in providing a base value derived from a nitrogen atom. Hindered phenol-type antioxidants are advantageous in that they do not provide any NOx gases.

Examples of hindered phenol-type antioxidants include 2,6-di-t-butyl-p-cresol, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-methylenebis(6-t-butyl-o-cresol), 4,4'-isopropylidenebis(2,6-di-t-butylphenol), 4,4'-bis(2,6-di-t-butylphenol), 2,2'-methylenebis(4-methyl -6-t-butylphenol), 4,4'-thiobis(2-methyl-6-t-butylphenol), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl)octadecyl propionate, and 3-(3,5 octyl 4-butyl-4-hydroxy-3-methylphenyl)propionate, and commercially available products such as, but not limited to, Irganox L135 (registered trademark in any country) (BASF), Naugalube 531 (registered trademark in any country) (Chemtura) and Ethanox 376 (registered trademark in any country) (SI Group).

Examples of diarylamine-type antioxidants include alkyldiphenylamines having a mixture of alkyl groups of 4 to 9 carbon atoms, p,p'-dioctyldiphenylamine, phenyl-naphthylamine, phenyl-naphthylamine, alkylated naphthylamines, and alkylated phenyl-naphthylamines.

Each of the hindered phenol-type antioxidants and diarylamine-type antioxidants can be used alone or in combination. Other oil-soluble antioxidants can be added if desired.

In the preparation of lubricating oil formulations, additives are added at 10 wt. % to 80 wt. % of active ingredient in the form of concentrates is common practice.

Typically, these concentrates may be diluted with 3 parts to 100 parts by weight (e.g., 5 parts to 40 parts by weight) of lubricating oil per weight part of the additive package in forming the finished lubricant (e.g., crankcase motor oil). The purpose of the concentrate is, of course, to make the handling of the various materials less difficult and cumbersome, as well as to facilitate their dissolution or dispersion in the final blend.

Process of Preparing Lubricating Oil Compositions The lubricating oil compositions disclosed herein can be prepared by any method known to those skilled in the art for making lubricating oils. In some embodiments, the base oil can be blended or mixed with the zirconium-containing compounds described herein. One or more others can be added if desired. Additives may be added to the base oil separately or simultaneously. In some embodiments, the additives are added to the base oil individually in one or more additions, in any order. In other embodiments, additives are added simultaneously to the base oil, optionally in the form of additive concentrates. In some embodiments, solubilizing the additive in the base oil may be aided by heating the mixture to a temperature of about 25°C to about 200°C, to a temperature of about 50°C to about 150°C, or to a temperature of about 75°C to about 125°C.

Any mixing or dispersing device known to those skilled in the art may be used to blend the ingredients, mix the ingredients, or solubilize the ingredients. Blending, mixing, or solubilizing may be performed using blenders, agitators, dispersers, mixers (e.g., planetary mixers and double planetary mixers), homogenizers (e.g., Gaulin homogenizers and Rannie homogenizers), mills (e.g., colloid mills, ball mills and sand mills), or any other mixing or dispersing equipment known in the art.

Applications of Lubricating Oil Compositions The lubricating oil compositions disclosed herein may be suitable for use as motor oils (i.e., engine oils or crankcase oils) in spark-ignited internal combustion engines, particularly in direct injection and supercharged engines.

The following examples are presented to illustrate various embodiments of the invention, but are not intended to limit the invention to the specific embodiments shown. All parts and percentages are by weight unless indicated to the contrary. All numbers are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the invention. Specific details described in each example should not be construed as necessary features of the invention.

EXAMPLES The following examples are intended for illustrative purposes only and are not intended to limit the scope of the invention in any way.

Example 1
A lubricating oil composition was prepared by blending together the following ingredients:
(a) a mixture of primary and secondary zinc dialkyldithiophosphates;
(b) a mixture of an overbased phenate detergent, an overbased borated sulfonate detergent and a low overbased calcium sulfonate detergent;
(c) a highly overbased magnesium sulfonate detergent (Mg sulfonate with a TBN of 402 and a Mg content of 9.4% wt);
(d) ethylene carbonate treated dispersants and borated succinimide dispersants;
(e) an alkylated diphenylamine-type antioxidant;
(f) a conventional amount of pour point depressant;
(g) a viscosity index improver based on ethylene propylene;
(h) a molybdenum succinimide antioxidant;
(i) a suds suppressor; and (j) a balance of a Group I base oil.

Example 2
Example 1 was repeated except for the highly overbased magnesium sulfonate with a TBN of 397 and a Mg content of 9.6% wt.

Example 3
Example 1 was repeated except that highly overbased calcium sulfonate and additional highly overbased magnesium sulfonate were added to the formulation to obtain the values shown in Table 2 below.

Comparative example 1
The overbased magnesium sulfonate was omitted from Example 1 and replaced with an amount of highly overbased calcium sulfonate to result in the values shown in Table 2 below.

Comparative example 2
In Example 1, the levels of overbased magnesium sulfonate were adjusted and high overbased calcium sulfonate was added to the values shown in Table 2 below.

Comparative example 3
In Example 1, the levels of overbased magnesium sulfonate were adjusted and high overbased calcium sulfonate was added to the values shown in Table 2 below.

Comparative example 4
In Example 1, the levels of overbased magnesium sulfonate were adjusted and high overbased calcium sulfonate was added to the values shown in Table 2 below.

Comparative example 5
In Example 1, the levels of overbased magnesium sulfonate were adjusted and high overbased calcium sulfonate was added to the values shown in Table 2 below.

Micro Clutch Test As a means of evaluating wet friction characteristics, measurements were performed based on the friction characteristics test method (JCMAS P 047 4) of hydraulic oil for construction machinery (JCMAS P 047:2004) of the Japan Construction Machinery Association. Details of the method for microclutch testing are provided below.

a) Operate the test apparatus for 5 minutes at room temperature using the conditions given in the test conditions below while measuring the coefficient of friction and temperature.
b) Operate the test apparatus at surface pressure and peripheral speed until the next test temperature controlled by the electric heater of the microclutch test rig is reached.
c) Measure the temperature and coefficient of friction while maintaining the test temperature for 5 minutes.

Test conditions Test specimen material: Clutch disc/facing material: SD1795-S
Plate material: SS400 steel (details of test specimen dimensions are shown in JACMAS P 047)
Test conditions: Temperature: 40, 60, 80, 100, 120, 140°C
Surface pressure: 392 kPa, peripheral speed: 3.0 × 10 ^-2 m / s (rotational speed: 20 min ^-1 )
Test liquid volume: 20ml

For new test clutches, break-in is required before measurements to obtain stable friction data. The conditions for running-in are as follows.

Temperature: room temperature Surface pressure: 392 kPa, peripheral speed: 3.0 × 10 ^-2 m / s (rotational speed: 20 min ^-1 )
Friction time: 60 minutes or more

The present invention is illustrated below by examples and comparative examples under the microclutch test conditions described above, but these are only representative examples and the present invention is in no way limited by them.

Diesel engine oils with JASO DH-1, API CG-4, CH-4, or CI-4 are widely used not only for internal combustion engines, but also for hydraulic systems and transmission systems in industrial machinery, especially transport, construction and agricultural machinery. Obtaining a higher static friction coefficient of wet clutches in those machines is important to enable safe operation of the machine, as it exhibits good response and fuel efficiency, and also to provide excellent power transmission efficiency for the machine. The coefficient of friction must be greater than 0.13 (0.125) for the oil at all test temperatures. It is clear that Examples 1, 2 and 3 exhibit excellent wet clutch friction in the Microclutch Test.

Claims (12)

Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
including
Phosphorus content is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
A lubricating oil composition having a Ca to Mg mass ratio of 1:2 to 4:1 and lubricating the crankcase and at least one of a wet clutch, a brake, a torque converter, a gear system, a hydrostatic transmission and a hydraulic system of an internal combustion engine of a vehicle. 2. The lubricating oil composition of claim 1, wherein the calcium derived from said calcium-containing detergent is present at least 1000 ppm of the lubricating oil composition. 2. The lubricating oil composition of claim 1, wherein the total base number (TBN) of the lubricating oil composition is from 8 mg KOH/g to 16 mg KOH/g. The sulphated ash content specified according to ASTM D874 is 0.00 . 80wt. % to 1 . 60wt. %. 2. The lubricating oil composition of claim 1, wherein the vehicle is an industrial machine, automobile, truck or other vehicle. 6. The lubricating oil composition according to claim 5, wherein the industrial machinery is transportation machinery, construction machinery or agricultural machinery. 2. The lubricating oil composition of claim 1, wherein the vehicle comprises an automatic transmission or a continuously variable transmission. A method for maintaining friction in a vehicle, comprising:
Ingredients:
(a) a major amount of oil of lubricating viscosity,
(b) a calcium-containing detergent;
(c) at least 800 ppm Mg from a magnesium-containing detergent;
(d) less than 600 ppm N from nitrogen-containing dispersants
lubricating the vehicle with a lubricating oil composition comprising
The phosphorus content of the lubricating oil composition is 0.06 wt. % to 0.15 wt. % and the sulfur content is 0.5 wt. % and the sulfated ash content is less than 0.8 wt. % to 2.0 wt. % and
wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and wherein the lubricating oil composition lubricates the crankcase of an internal combustion engine of the vehicle and at least one of wet clutches, brakes, torque converters, gear systems, hydrostatic transmissions and hydraulic systems. 9. The method of claim 8, wherein calcium derived from said calcium-containing detergent is present at least 1000 ppm of the lubricating oil composition. 9. The method of claim 8, wherein the vehicle is an industrial machine, automobile, truck or other vehicle. 11. The lubricating oil composition of claim 10, wherein the industrial machinery is transportation, construction or agricultural machinery. 9. The method of claim 8, wherein the vehicle comprises an automatic transmission or a continuously variable transmission.