HIGH PERFORMANCE GEAR OILS AND RELATED METHODS

Abstract

Gear oil compositions and methods of making the same. Gear oil compositions may comprise: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; and a performance additive package, where the gear oil compositions exhibit, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced with a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, rust formation, pour point, wearing, oxidation; equivalent or increased demulsibility, and any combination thereof. Methods of improving low temperature fluidity and/or oxidation stability of a gear oil composition may comprise providing said base oil, optionally providing said performance additive package, and optionally, blending said base oil with said performance additive package, thereby forming said gear oil composition.

Description

FIELD OF THE DISCLOSURE

This application relates to lubricant oil compositions having improved oil life and energy efficiency and, more particularly, to gear oil compositions and methods thereof.

BACKGROUND

Base oils are a major constituent in industrial oils and contribute significantly to the final properties of these products, such as low temperature performance, biodegradability, energy efficiency, and high temperature oxidation stability. Each base oil possesses distinct characteristics that are needed to satisfy the specific operation requirements of a particular industrial oil composition.

Gear oils, for example, are oils that are used as lubricants in gears to reduce friction and wear to enable parts to move smoothly. Gear oils contain two general components, namely, one or more oil base stocks and additives. Gear oils require exceptional oil life, often tens of thousands of hours, as well as high energy efficiency, both high fluidity at low temperatures and high film thickness at high temperatures. There is a desire to improve the oil life by improving the oil oxidative and shear stability, as well as to improve the oil energy efficiency by reducing the oil coefficient of traction. By improving the energy efficiency of and by extending the life of gear oils, significant sustainability benefits in energy savings and reduced oil waste can be achieved.

SUMMARY OF THE DISCLOSURE

Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an exhaustive overview of the disclosure and is neither intended to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary purpose of this summary is to present some concepts of the disclosure in a simplified form prior to the more detailed description that is presented hereinafter.

According to an embodiment consistent with the present disclosure, a gear oil composition includes: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein the gear oil composition exhibits one or more of the following, as compared to a corresponding gear oil composition wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

According to an additional embodiment consistent with the present disclosure, a gear oil composition includes a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

According to a further embodiment consistent with the present disclosure, a method for producing a gear oil composition having low-temperature fluidity and/or oxidation stability includes: providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; optionally, providing a performance additive package; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting one or more of the following, as compared to a corresponding gear oil composition wherein 50 wt. % or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

According to an additional embodiment consistent with the present disclosure, a method for producing a gear oil composition includes providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; optionally, providing a performance additive package; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

According to a further embodiment consistent with the present disclosure, a gear oil composition includes a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

According to yet a further embodiment consistent with the present disclosure, a method for producing a gear oil composition includes providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; providing a performance additive package; and blending the base oil with the performance additive package, thereby forming a gear oil composition wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

Any combinations of the various embodiments and implementations disclosed herein can be used in a further embodiment, consistent with the disclosure. These and other features and attributes of the disclosed compositions and methods of the present disclosure and their advantageous applications and/or uses will be apparent from the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Not Applicable.

DETAILED DESCRIPTION

This application relates to compositions suitable as lubricants and, more particularly, for use as gear oils, and methods concerning the same.

The present disclosure provides gear oil compositions comprising at least one Group II/II+ extra heavy neutral oil base stock. The gear oil compositions described herein advantageously perform lubrication in gears to reduce friction and wear to enable parts to move smoothly to the same level of more costly corresponding compositions comprising typical oil base stocks (e.g., poly-α-olefin (PAO) oil base stocks (including conventional PAO and metallocene PAO (mPAO) oil base stocks), coal-to-liquid (CTL) oil base stocks, gas-to-liquid (GTL) oil base stocks, or ethylene-α-olefin copolymer (EAO) oil base stocks). Accordingly, the described gear oils provide significant advantages in areas of oil life and energy efficiency without compromising performance.

Gear oils of the present disclosure may further provide equivalent or improved low-temperature fluidity, oxidation stability, wear resistance, corrosion resistance, and/or water separability, as compared to typical gear oil compositions (e.g., PAO-based, CTL-based, GTL-based, or EAO-based gear oil compositions). Unexpectedly, the gear oils of the present disclosure further achieve industry standards and regulations, the benefits listed herein, without sacrificing performance or cleanliness. Further, and unexpectedly, the described gear oil shows equivalent or improved properties not previously attainable by oil base stocks other than Group IV and Group V oil base stocks.

Accordingly, in an embodiment, the present disclosure provides gear oil compositions comprising a base oil and a performance additive package, where the base oil comprises a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and wherein the gear oil compositions exhibit one or more of the following, as compared to a corresponding gear oil composition wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

Accordingly, in another embodiment, the present disclosure provides gear oil compositions comprising a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

Accordingly, in yet another embodiment, the present disclosure provides gear oil compositions comprising a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172;

• • equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

In another embodiment, the present disclosure provides methods for producing a gear oil composition exhibiting equivalent or improved performance, the methods comprising: providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting one or more of the following, as compared to a corresponding gear oil composition wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

In another embodiment, the present disclosure provides methods for producing a gear oil composition comprising providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; optionally, providing a performance additive package; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

In another embodiment, the present disclosure provides methods for producing a gear oil composition comprising providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; providing a performance additive package; and blending the base oil with the performance additive package, thereby forming a gear oil composition wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

Definitions

As used herein, the term “wt. %,” and grammatical variations thereof, refer generally to percentage (also referred to herein as “percent” or “%”) by weight. As used herein, the term “vol. %,” and grammatical variations thereof, refer generally to percentage by volume. As used herein, the term “mol %,” and grammatical variations thereof, refer generally to percentage by mole. As used herein, the term “ppm,” and grammatical variations thereof, refer generally to parts per million. As used herein, the terms “ppm wt.,” “wppm,” and grammatical variations thereof, refer generally to parts per million on a weight basis. As used herein, the term “wt. ratio,” and grammatical variations thereof, refer generally to weight ratio. As used herein, the term “vol. ratio,” and grammatical variations thereof, refer generally to volume ratio. As used herein, the term “mol ratio,” and grammatical variations thereof, refer generally to mole ratio. All concentrations herein, unless otherwise stated, are expressed on the basis of the total amount of the composition in question.

As used herein, the terms “lubricant,” “lubricating oil,” and grammatical variations thereof, refer generally to a substance (usually a fluid under operating conditions) suitable for introduction between two moving surfaces of a system to reduce the friction and wear between said surfaces.

As used herein, the term “base oil,” and grammatical variations thereof, refer generally to the fluid component of a lubricant composition or lubricating oil composition, which may comprise one or more different oil base stocks.

As used herein, the term “oil base stock,” and grammatical variations thereof, refer generally to any fluid that could be used in a base oil, including, but not limited to, a terpene, a mineral oil, a synthetic hydrocarbon, an ester, the like, or any combination thereof. An oil base stock, as described herein, may be defined according to the American Petroleum Institute (API) base oil classification system, which categorizes oil base stocks into five groups based on their saturated hydrocarbon content, sulfur level.

As used herein, the terms “viscosity index”, “VI,” and grammatical variations thereof, refer generally to an empirical, unit-less number indicating the effect of temperature change on the kinematic viscosity of the oil base stock, base oil, or lubricant composition. A higher viscosity index indicates a smaller decrease in kinematic viscosity with increasing temperature. An oil base stock, base oil, or lubricant composition may have a VI value as determined by ASTM D2270.

Oil base stocks are typically produced on a large scale from non-renewable petroleum sources. As used herein, the term “Group I oil base stocks,” and grammatical variations thereof, refer generally to refined crude oils which are the least refined, undergoing solvent refining, comprising less than 90% saturates and/or greater than 0.03% sulfur, and having a viscosity index (VI) of about 80-120. As used herein, the term “Group II oil base stock,” and grammatical variations thereof, refer generally to refined crude oils which are more refined than Group I oil base stocks, both solvent refined and hydrocracked, to achieve more than 90% saturates, less than 0.03% sulfur, and having a viscosity index (VI) of about 80-120. As used herein, the term “Group III oil base stock,” and grammatical variations thereof, refer generally to refined crude oils which undergo severe hydro-processing (e.g., hydro-cracking, hydro-isomerization, and/or hydro-treating) to achieve the same refinement standards as Group II, while having a VI greater than 120. As used herein, the term “Group IV oil base stock,” and grammatical variations thereof, refer generally to synthetic poly-α-olefins (PAOs) (e.g., produced by oligomerization of α-olefins, such as 1-decene, 1-butene, and propene), comprising conventional PAOs and metallocene PAOs (e.g., produced using a metallocene catalyst), typically with a VI of 125-300. As used herein, the term “Group V oil base stock,” and grammatical variations thereof, refer generally to include all base stocks that do not belong to Groups I-IV, such as alkylated naphthalenes, alkylated benzenes, polyalkylene glycols (PAG), and esters.

Further designations commonly used by oil producers, but not officially recognized by the API, may be used, including Group II+ oil base stocks and Group III+ oil base stocks. As used herein, the term “Group II+ oil base stock,” and grammatical variations thereof, refer generally to Group II oil base stock which are further treated (e.g., hydro-treated) to have a VI of from about 110 to about 120. As used herein, the term “Group III+ oil base stock,” and grammatical variations thereof, refer generally to synthetic oils, e.g., produced by Fischer-Tropsch reactions of hydrogen and carbon monoxide (e.g., CTL oil base stocks, GTL oil base stocks) having a VI of approximately 135-145.

Oil base stocks may be alternatively defined by a viscosity and/or volatility grade classification, which varies from producer to producer. Generally, viscosity grade classifications range, in order of increasing viscosity and mid-point boiling point. As used herein, the terms “kinematic viscosity,” “KV,” and grammatical variations thereof, refer generally to the ratio of the dynamic viscosity to the density of a material at the same temperature and pressure. The gear oil compositions may have a KV measured at a defined temperature as defined by ASTM D445 or ASTM D7279 or ASTM D7042. Shorthand terms for kinematic viscosity at commonly used defined temperatures are KV100 (e.g., 100° C.) and KV40 (e.g., 40° C.).

As used herein, the term “light neutral oil base stock,” and grammatical variations thereof, refer generally to an oil base stock having a KV100 of about 4-6 cSt. As used herein, the term “medium neutral oil base stocks,” and grammatical variations thereof, refer generally to oil base stocks having a KV100 of about 7-9 cSt. As used herein, the term “Heavy neutral oil base stocks,” and grammatical variations thereof, refer generally to oil base stocks having a KV100 of about 10-12 cSt. As used herein, the term “extra heavy neutral oil base stock,” and grammatical variations thereof, refer generally to an oil base stock with KV100 of ≥ about 30 cSt. As used herein, the term “Group II/II+ extra heavy neutral oil base stock,” and grammatical variations thereof, refer generally to a Group II oil base stock, a Group II+ oil base stock, or any combination thereof, which meets the KV100 requirements of an extra heavy neutral oil base stock.

Oil base stocks may be defined by a cold cranking viscosity (“CCS”) determined using American Society for Testing and Materials Test Method (ASTM) D5893, which is the Standard Test Method for Apparent Viscosity of Engine Oils Between −5 and −35 C Using the Cold Crank Simulator. An oil base stock may also be defined by a Noack volatility, determined using ASTM D5800, which is the Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method. An oil base stock may be defined as a “Trim Stock,” which refers to an oil base stock that may be blended at a lesser amount with other oil base stocks of a base oil or lubricant to bring a viscosity, CCS value, and/or a Noack volatility of a blended base oil into a desired range. In an embodiment, a Trim Stock is a lighter oil base stock (i.e., having a lower boiling point and/or kinematic viscosity, e.g., KV100) than other oil base stocks of a base oil or lubricant.

All references herein to ASTM standards refer to the edition most recently published before the priority date of the present application unless a different edition is expressly identified.

Gear Oil Compositions

In an aspect, the present disclosure provides gear oil compositions. In an embodiment, gear oil compositions of the present disclosure are prepared by methods of the present disclosure. As used herein, the term “gear oil,” and grammatical variations thereof, refer generally to oils that are used for centralized lubrication of various systems in industrial machines, such as bearings and gears, where the oil is continuously circulated to the friction points of system components, collected, and recirculated.

Gear oil compositions of the present disclosure comprise: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package. Gear oil compositions of the present disclosure may have various equivalent or improved performance values, as compared to a typical gear oil composition, e.g., where a typical base oil thereof (e.g., a PAO, a CTL, a GTL, or an EAO-based base oil) is replaced with a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, where the base oils are matched for rheological properties. Equivalent or improved performance may be observed where a portion of or all of the oil base stock of a typical gear oil composition is replaced with a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock.

A gear oil composition of the disclosure, comprising base oils comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, may display an equivalent or improved fluidity at a lower temperature, oxidation stability, the like, or any combination thereof, as compared to a typical gear oil composition, e.g., a composition comprising a Group IV oil base stock and lacking a Group II/II+ extra heavy neutral oil base stock. A gear oil composition of the disclosure may display from about 5% to about 40% improved performance properties, including all % values and subsets therebetween (e.g., from about 10% to about 30% improved performance), as compared to a typical gear oil composition.

In an embodiment, gear oil compositions of the present disclosure exhibit improved performance, as compared to corresponding gear oil compositions wherein at least a portion of or all of the Group II/II+ extra heavy neutral oil base stock is replaced with a Group IV oil base stock. In an embodiment, the corresponding gear oil compositions comprise the Group IV oil base stock at 50 wt. % or more, including all wt. % values and subsets therebetween (e.g., greater than about 55 wt. %, greater than about 60 wt. %, greater than about 65 wt. %, greater than about 70 wt. %, greater than about 75 wt. %, greater than about 80 wt. %, greater than about 85 wt. %, greater than about 90 wt. %, greater than about 95 wt. %, greater than about 99 wt. %, or 100 wt. %), based on the total weight of the Group II/II+ extra heavy neutral oil base stock. In one embodiment, 50 wt. % of the Group II/II+ extra heavy neutral oil base stock with the Group IV oil base stock is replaced in the corresponding gear oil composition. In an embodiment, the Group IV oil base stock is a conventional PAO oil base stock. In an embodiment, the conventional PAO oil base stock is a mixture of conventional PAO 40 and conventional PAO 100 oil base stocks.

In an embodiment, gear oil compositions of the present disclosure exhibit improved performance, as compared to corresponding gear oil compositions wherein at least a portion of or all of the Group II/II+ extra heavy neutral oil base stock is replaced with a Group IV oil base stock. In an embodiment, the corresponding gear oil compositions comprise the Group IV oil base stock at 40 wt. % or more, including all wt. % values and subsets therebetween (e.g., greater than about 45 wt %, greater than about 50 wt %, greater than about 55 wt. %, greater than about 60 wt. %, greater than about 65 wt. %, greater than about 70 wt. %, greater than about 75 wt. %, greater than about 80 wt. %, greater than about 85 wt. %, greater than about 90 wt. %, greater than about 95 wt. %, greater than about 99 wt. %, or 100 wt. %), based on the total weight of the Group II/II+ extra heavy neutral oil base stock. In one embodiment, 40 wt. % of the Group II/II+ extra heavy neutral oil base stock with the Group IV oil base stock is replaced in the corresponding gear oil composition. In an embodiment, the Group IV oil base stock is a conventional PAO oil base stock. In an embodiment, the conventional PAO oil base stock is a mixture of conventional PAO 40 and conventional PAO 100 oil base stocks.

Gear oil compositions of the present disclosure may be specifically formulated for equivalent or improved performance, particularly for improved energy efficiency and/or improved oil life. Unexpectedly, gear oil compositions of the present disclosure may achieve equivalent or improved performance (e.g., corrosiveness, demulsibility, pour point, wearing, oxidation stability, deposits, the like, or any combination thereof) compared to typical gear oil compositions, e.g., PAO-based, CTL-based, GTL-based, or EAO-based gear oil compositions, or the like.

In an embodiment, gear oil compositions of the present disclosure exhibit improved oxidation stability, as compared to corresponding gear oil compositions wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced with a Group IV oil base stock. In an embodiment, the Group IV oil base stock is a conventional PAO oil base stock. In an embodiment, the conventional PAO oil base stock is a mixture of conventional PAO 40 and conventional PAO 100 oil base stocks. In an embodiment, said improved oxidation stability is a reduced KV100 increase as measured by an ExxonMobil B10 oxidation test.

In an embodiment, gear oil compositions of the present disclosure exhibit improved oxidation stability, as compared to corresponding gear oil compositions wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced with a Group IV oil base stock. In an embodiment, the Group IV oil base stock is a conventional PAO oil base stock. In an embodiment, the conventional PAO oil base stock is a mixture of conventional PAO 40 and conventional PAO 100 oil base stocks. In an embodiment, said improved oxidation stability is a reduced KV100 increase as measured by an ExxonMobil B10 oxidation test.

Gear oil compositions of the present disclosure may have various performance values (e.g., viscometrics, corrosiveness, demulsibility, pour point, wearing, oxidation stability, deposits, or the like). The gear oil compositions of the present disclosure may be competitive with or superior to PAO-based, CTL-based, GTL-based, or EAO-based gear oil compositions in one or more performance properties.

Gear oil compositions may have various kinematic viscosity values. The gear oil compositions may have a KV40, as determined by ASTM D445, of from about 10 centistokes (cSt) to about 700 cSt, including all cSt values and subsets therebetween (e.g., from about 25 cSt to about 600 cSt, from about 50 cSt to about 600 cSt, from about 100 cSt, to about 200 cSt, from about 100 cSt to about 300 cSt, from about 100 cSt to about 400 cSt, from about 100 cSt, to about 500 cSt, from about 100 cSt to about 600 cSt, from about 200 cSt to about 300 cSt, from about 200 cSt to about 400 cSt, from about 200 cSt to about 500 cSt, from about 200 cSt to about 600 cSt, from about 300 cSt to about 400 cSt, from about 300 cSt to about 500 cSt, from about 300 cSt to about 600 cSt, from about 400 cSt to about 500 cSt, or from about 400 cSt to about 600 cSt). In an embodiment, the gear oil compositions exhibit one or more of the following: a KV40, as determined by ASTM D445, of from about 200 cSt to about 330 cSt.

Gear oil compositions may have a KV100 value of from about 10 cSt to about 70 cSt, including all cSt values and subsets therebetween (e.g., from about 10 cSt to about 60 cSt, from about 10 cSt to about 50 cSt, from about 10 cSt to about 40 cSt, from about 10 cSt to about 30 cSt, from about 10 cSt to about 20 cSt, from about 20 cSt to about 70 cSt, from about 20 cSt to about 60 cSt, from about 20 cSt to about 50 cSt, from about 20 cSt to about 40 cSt, from about 20 cSt to about 30 cSt, from about 30 cSt to about 70 cSt, from about 30 cSt to about 60 cSt, from about 30 cSt to about 50 cSt, from about 30 cSt to about 40 cSt, from about 40 cSt to about 70 cSt, from about 20 cSt to about 60 cSt, or from about 40 cSt to about 50 cSt). In an embodiment, the gear oil compositions exhibit a KV100, as determined by ASTM D445, of from about 10 cSt to about 50 cSt.

Gear oil compositions may have various viscosity index (“VI”) values. The gear oil compositions may have a viscosity index (“VI”) as determined by ASTM D2270. The gear oil compositions may have a VI of from about 80 to about 180, including all values and subsets therebetween (e.g., from about 80 to about 170, from about 80 to about 160, from about 80 to about 150, from about 80 to about 140, from about 80 to about 130, from about 80 to about 120, from about 80 to about 110, from about 80 to about 100, from about 80 to about 90, from about 90 to about 180, from about 90 to about 170, from about 90 to about 160, from about 90 to about 150, from about 90 to about 140, from about 90 to about 130, from about 90 to about 120, from about 90 to about 110, from about 90 to about 100, from about 100 to about 180, from about 100 to about 170, from about 100 to about 160, from about 100 to about 150, from about 100 to about 140, from about 100 to about 130, from about 100 to about 120, from about 100 to about 110, from about 110 to about 180, from about 110 to about 170, from about 110 to about 160, from about 110 to about 150, from about 110 to about 140, from about 110 to about 130, from about 110 to about 120, from about 120 to about 180, from about 120 to about 170, from about 120 to about 160, from about 120 to about 150, from about 120 to about 140, from about 120 to about 130, from about 130 to about 180, from about 130 to about 170, from about 130 to about 160, from about 130 to about 150, from about 130 to about 140, from about 140 to about 180, from about 140 to about 170, from about 140 to about 160, from about 140 to about 150, from about 150 to about 180, from about 150 to about 170, from about 150 to about 160, from about 160 to about 180, from about 160 to about 170, from about 170 to about 180). In an embodiment, the gear oil compositions exhibit a VI, as determined by ASTM D2270, of from about 90 to about 160.

In an embodiment, gear oil compositions may exhibit a VI, as determined by ASTM D2270, of from about 120 to about 150, including all values and subsets therebetween.

Gear oil compositions may have various pour point values. As used herein, the term “pour point,” and grammatical variations thereof, refer generally to the temperature at which an oil becomes semi-solid and loses its flow characteristics. The gear oil compositions may have a pour point as determined by International Standard Test Method (“IP”) 15 or ASTM D97 or ASTM D7345. The gear oil compositions may have a pour point of from about −60° C. to about −20° C., including all ° C. values and subsets therebetween (e.g., from about −60° C. to about −20° C., from about −60° C. to about −25° C., from about −60° C. to about −30° C., from about −60° C. to about −35° C., from about −60° C. to about −40° C., from about −60° C. to about −45° C., from about −60° C. to about −50° C., from about −60° C. to about −55° C., from about −55° C. to about −20° C., from about −55° C. to about −25° C., from about −55° C. to about −30° C., from about −55° C. to about −35° C., from about −55° C. to about −40° C., from about −55° C. to about −45° C., from about −55° C. to about −50° C., from about −50° C. to about −40° C., from about −50° C. to about −35° C., from about −50° C. to about −30° C., from about −50° C. to about −25° C., from about −45° C. to about −20° C., from about −45° C. to about −25° C., from about −45° C. to about −30° C., from about −45° C. to about −35° C., from about −45° C. to about −40° C., from about −40° C. to about −20° C., from about −40° C. to about −25° C., from about −40° C. to about −30° C., from about −40° C. to about −35° C., from about −35° C. to about −20° C., from about −35° C. to about −25° C., from about −35° C. to about −30° C., from about −30° C. to about −20° C., or from about −30° C. to about −25° C.). In an embodiment, the gear oil compositions exhibit a pour point, as determined by ASTM D97, of from about −60° C. to about −30° C. The gear oil compositions of the present disclosure accordingly are competitive with traditional gear oil compositions (e.g., PAO-based gear oil compositions), even without a pour point depressant.

A tested pour point of a gear oil composition of the disclosure may be considered equivalent to the reference pour point of a corresponding gear oil composition if the tested pour point is within the 95% confidence interval of reproducibility for mineral oil lubricants set forth in ASTM D97 (e.g., 6.43° C.) or ASTM D5949.

In an embodiment, gear oil compositions may exhibit a pour point, as determined by ASTM D97 or ASTM D5949, of from about −40° C. to about −20° C.

Gear oil compositions may have various corrosiveness values. Corrosiveness can be determined by a number of corrosivity tests, including ASTM D130 (e.g., copper corrosion), and ASTM D665 (e.g., rust formation in synthetic seawater (Procedure B)). The gear oil compositions may have a corrosiveness to copper rating of 1 A, as determined by ASTM D130 (@ 212° F., 3 hours (hrs)) and/or may have a passing visual rating for rust formation in seawater, as determined by ASTM D665 (@140° F., 24 hrs).

Gear oil compositions may have various demulsibility values. As used herein, the term “demulsibility,” and grammatical variations thereof, refer generally to the ability of a lubricant to separate from water and prevent the formation of emulsions of water and a lubricant. Demulsibility can be determined by a number of water separation tests, including ASTM D1401 or ASTM D2711. The gear oil compositions may have demulsibility time (time to reach 37 mL of water (min)) of about 10 minutes and/or an Oil-Water-Emulsion volume (mL) of about 41-39-0, as determined by ASTM D1401 (@82° C.). The gear oil compositions may have a total emulsion volume of about zero (0) mL, a total free water volume of from about 80 mL to about 85 mL, and/or a % Water in Oil of from about 0.1% to about 0.5%, as determined by ASTM D2711 Procedure B (@82° C.).

In some embodiments, gear oil compositions may have an Oil-Water-Emulsion volume (mL) of about 41-39-0 to about 42-38-0, as determined by ASTM D1401 (@82° C.). In some embodiments, gear oil compositions may have a % Water in Oil of from about 0.4% to about 0.5%, as determined by ASTM D2711 Procedure B (@82° C.).

A tested demulsibility time determined by ASTM D1401 of a gear oil composition of the disclosure may be considered equivalent to the reference demulsibility time of a corresponding gear oil composition if the tested demulsibility time is within the 95% confidence interval of reproducibility set forth in ASTM D1401.

A tested oil-water-emulsion volume determined by ASTM D1401 of a gear oil composition of the disclosure may be considered equivalent to the reference oil-water-emulsion volume of a corresponding gear oil composition if the tested oil-water-emulsion volume is within the 95% confidence interval of reproducibility set forth in ASTM D1401.

A tested total free water volume determined by ASTM D2711 of a gear oil composition of the disclosure may be considered equivalent to the reference total free water volume of a corresponding gear oil composition if the tested total free water volume is within the 95% confidence interval of reproducibility set forth in ASTM D2711.

Gear oil compositions may have various foaming values (i.e., after air is blown or otherwise mixed into the composition). Foaming tendency (i.e., foam volume (mL)) after 5 minutes (min) air blowing) and foaming stability (i.e., foam volume (mL)) after 10 min cessation of air blowing) can be determined by ASTM D892 sequences I-III (I, III @24° C., II @93.5° C.). The gear oil compositions may have an ASTM D892 Sequence I-III tendency/stability of from about 0-10/0-10.

A foaming tendency determined by ASTM D892 of a gear oil composition of the disclosure may be considered equivalent to the reference foaming tendency of a corresponding gear oil composition if the tested foaming tendency is within the 95% confidence interval of reproducibility set forth in ASTM D892.

A foaming stability determined by ASTM D892 of a gear oil composition of the disclosure may be considered equivalent to the reference foaming stability of a corresponding gear oil composition if the tested foaming stability is within the 95% confidence interval of reproducibility set forth in ASTM D892.

Gear oil compositions may have various oxidation stability values. As used herein, the term “oxidation stability,” and grammatical variations thereof, refer generally to the resistance of an oil to react with oxygen, which can cause degradation and contribute to varnish, deposits, and poor machine performance. Oxidation stability can be measured by a number of oxidation tests, including the ExxonMobil B10 oxidation test (e.g., see U.S. Pat. Nos. 3,682,980, 3,445,391, 4,981,492 and 5,486,301, the disclosures of which are incorporated herein by reference) or ASTM D2272 or ASTM D2893.

In an embodiment, gear oil compositions of the present disclosure may have an ExxonMobil B10 oxidation test (@163° C., 120 hrs) sludge rating of Nil or Trace. In an embodiment, gear oil compositions of the present disclosure may have an ExxonMobil B10 oxidation test (@163° C., 120 hrs) KV100% increase of about 10% or less, including all % values and subsets therebetween (e.g., about 10%, about 9.9% or less, about 9.8% or less, about 9.5% or less, about 8% or less, about 7% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less, or from about 1% to about 9.9%). In an embodiment, gear oil compositions of the present disclosure may have an ExxonMobil B10 oxidation test (@163° C., 120 hrs) KV100% increase of up to about 7% or less. In an embodiment, gear oil compositions of the present disclosure may have an ExxonMobil B10 oxidation test (@163° C., 120 hrs) KV100% increase of up to about 6% or less.

A KV100 increase determined by ExxonMobil B10 Oxidation test of a gear oil composition of the disclosure may be considered equivalent to the reference KV100 increase of a corresponding gear oil composition if the tested KV100 increase is no more than the 1 percentage point greater than the reference KV100 increase of the corresponding gear oil composition.

In an embodiment, gear oil compositions of the present disclosure may have a Rotating Pressure Vessel Oxidation Test (RPVOT) oxidation stability, as determined by ASTM D2272, of from about 200 minutes (min) to about 400 min. In an embodiment, gear oil compositions of the present disclosure may have a sludge value, as determined by ASTM D2893 at 121 C, of from about 50 mL to about 110 mL. In an embodiment, gear oil compositions of the present disclosure may have an ASTM D91 precipitation number, as determined by ASTM D2893, of about 0.1 or less. In an embodiment, gear oil compositions of the present disclosure may have an acid number increase, as determined by ASTM D2893, of from about −0.5 to about −0.1 mL KOH/g. In an embodiment, gear oil compositions of the present disclosure may have a KV100% increase, as determined by ASTM D2893, of from about 1.0% to about 10%.

In an embodiment, gear oil compositions of the present disclosure may have an RPVOT oxidation stability, as determined by ASTM D2272, of from about 700 minutes (min) to about 950 min, including all values and subsets therebetween, such as from about 700 min to about 900 min, about 700 min to about 850 min, about 700 min to about 800 min, about 700 min to about 750 min, about 750 min to about 950 min, about 750 min to about 900 min, about 750 min to about 850 min, about 750 min to about 800 min, about 800 min to about 950 min, about 800 min to about 900 min, about 800 min to about 850 min, about 850 min to about 950 min, about 850 min to about 900 min, or about 900 min to about 950 min.

An RPVOT time determined by ASTM D2272 of a gear oil composition of the disclosure may be considered equivalent to the RPVOT time of a corresponding gear oil composition if the tested RPVOT time is within the 95% confidence interval of reproducibility set forth in ASTM D2272.

In an embodiment, gear oil compositions of the present disclosure may have a sludge value, as determined by ASTM D2893 (121° C., 13 days), of from about 30 mL to about 155 mL. In an embodiment, gear oil compositions of the present disclosure may have an ASTM D91 precipitation number, as determined by ASTM D2893 (121° C., 13 days), of about 0.025 or less. In an embodiment, gear oil compositions of the present disclosure may have an acid number increase, as determined by ASTM D2893 (121° C., 13 days), of from about −0.3 to about 0.3 mL KOH/g. In an embodiment, gear oil compositions of the present disclosure may have a KV100% increase, as determined by ASTM D2893, of from about 1% to about 4%.

Gear oil compositions may have various antiwearing values. Antiwearing values can be determined by ASTM D2783 or ASTM D4172. In an embodiment, gear oil compositions of the present disclosure may have a weld load of from about 180 kgf to about 250 kgf, according to ASTM D2783. In an embodiment, gear oil compositions of the present disclosure may have a scar diameter (@ 20 kg, 1800 rpm, 1 hr, 54° C.) of from about 0.1 mm to about 0.5 mm, according to ASTM D4172.

In an embodiment, gear oil compositions of the present disclosure may have a weld load of from about 180 kgf to about 220 kgf, according to ASTM D2783. In an embodiment, gear oil compositions of the present disclosure may have a scar diameter (@ 20 kg, 1800 rpm, 1 hr, 54° C.) of from about 0.2 mm to about 0.4 mm, according to ASTM D4172. In an embodiment, gear oil compositions of the present disclosure may have a last non-seizure load value according to ASTM D2783 of about 75 kgf to about 130 kgf.

In an embodiment, gear oil compositions may exhibit one or more of the following, as compared to a corresponding gear oil composition, wherein 50 weight percent (wt. %) or more the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

Relative to any corresponding gear oil composition wherein 40 wt %, 50 wt %, or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, gear oil compositions may exhibit any one, any two, any three, any four, any five, or all six of equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

In an embodiment, gear oil compositions may exhibit, as compared to a corresponding gear oil composition, wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

In an embodiment, gear oil compositions may exhibit, as compared to a corresponding gear oil composition, wherein 100 weight percent (wt. %) of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

In an embodiment, gear oil compositions exhibit one or more of the following: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from about 200 cSt to about 350 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from about 10 cSt to about 50 cSt; and a viscosity index (VI), as determined by ASTM D2270, of from about 90 to about 150. In an embodiment, gear oil compositions exhibit one or more of the following: a pour point, as determined by ASTM D97, of from about −60° C. to about −30° C.; and a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ASTM D2893, of about 7% or less.

In an embodiment, gear oil compositions may exhibit one or more properties selected from the group consisting of a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150, any combination thereof; and any combination thereof.

In an embodiment, gear oil compositions may exhibit a property selected from the group consisting of: a pour point, as determined by ASTM D97, of from −50° C. to −30° C.; a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less, and any combination thereof.

Group II/II+ Extra Heavy Neutral Oil Base Stocks

As used herein, Group II/II+ extra heavy neutral oil base stocks may be produced through catalytic processing or through hydrotreatment (sour conditions) followed by catalytic dewaxing (sweet conditions) of de-asphalted Group II oil base stocks and/or Group II+ oil base stocks. Gear oil compositions of the present disclosure, due to the use of extra-heavy Group II/II+ oil base stocks, may allow for increased performance similar to or exceeding performance standards of gear oils formulated with solely Group IV oil base stocks (e.g., PAOs) while having lower cost. A suitable example of a commercially available Group II/II+ extra heavy neutral oil base stock includes, but is not limited to, EHC 340 MAX™ (ExxonMobil Corporation).

Group II/II+ extra heavy neutral oil base stocks may have various rheological properties. Group II/II+ extra heavy neutral oil base stocks may have various kinematic viscosity values. Suitable Group II/II+ extra heavy neutral oil base stocks may have a KV40 of from about 250 cSt to about 600 cSt, including all cSt values and subsets therebetween (e.g., from about 250 cSt to about 300 cSt, from about 250 cSt to about 450 cSt, from about 300 cSt to about 450 cSt, from about 300 cSt to about 600 cSt, or from about 450 cSt to about 600 cSt). Suitable Group II/II+ extra heavy neutral oil base stocks may have a KV100 of from about 15 cSt to about 70 cSt, including all cSt values and subsets therebetween (e.g., from about 15 cSt to about 25 cSt, from about 15 cSt to about 50 cSt, from about 25 cSt to about 50 cSt, from about 25 cSt to about 70 cSt).

Group II/II+ extra heavy neutral oil base stocks may have various VI values. Suitable Group II/II+ extra heavy neutral oil base stocks may have a viscosity index (ASTM D2270) of from about 80 to about 140, including all values and subsets therebetween (e.g., from about 90 to about 100, from about 90 to about 110, from about 90 to about 115, from about 95 to about 105, from about 95 to about 115, from about 100 to about 110, or from about 100 to about 130).

Other suitable Group II/II+ extra heavy neutral oil base stocks may have a viscosity index (ASTM D2270) of from about 80 to about 120, including all values and subsets therebetween (e.g., about 80 to about 110, about 80 to about 100, about 80 to about 90, about 90 to about 120, about 90 to about 110, about 90 to about 100, about 100 to about 120, about 100 to about 110, or about 110 to about 120).

Group II/II+ extra heavy neutral oil base stocks may have various pour point values. Suitable Group II/II+ extra heavy neutral oil base stocks may have a pour point (IP 15 or ASTM D97 or ASTM D7345) of from about −60° C. to about −10° C., including all ° C. values and subsets therebetween (e.g., from about −45° C. to about −20° C., from about −45° C. to about −25° C., from about −45° C. to about −30° C., from about −55° C. to about −35° C., from about −40° C. to about −25° C., from about −40° C. to about −30° C., from about −35° C. to about −20° C., from about −35° C. to about −25° C., or from about −30° C. to about −20° C.). In an embodiment, Group II/II+ extra heavy neutral oil base stocks may have lower pour points, as compared to typical oil base stocks having the same viscosity (e.g., KV40 or KV100) values, including but not limited to PAO oil base stocks, GTL oil base stocks, EAO oil base stocks, and the like.

Other suitable Group II/II+ extra heavy neutral oil base stocks may have a pour point (IP 15 or ASTM D97 or ASTM D7345) of from about −50° C. to about −10° C., including all values and subsets therebetween (e.g., from about −45° C. to about −20° C., from about −45° C. to about −25° C., from about −45° C. to about −30° C., from about −45° C. to about −35° C., from about −40° C. to about −25° C., from about −40° C. to about −30° C., from about −35° C. to about −20° C., from about −35° C. to about −25° C., or from about −30° C. to about −20° C.).

Group II/II+ extra heavy neutral oil base stocks may have various oxidation stability values. In an embodiment, Group II/II+ extra heavy neutral oil base stocks may have a KV100% increase (ASTM D2893) of about 10% or less, including all % values and subsets therebetween (e.g., about 10%, about 9.9% or less, about 9.8% or less, about 9.5% or less, about 8% or less, about 7% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less, or from about 1% to about 9.9%).

In an embodiment, Group II/II+ extra heavy neutral oil base stocks have: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from about 250 cSt to about 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from about 15 cSt to about 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from about 80 to about 160; and/or a pour point, as determined by ASTM D97, of from about −60° C. to about −10° C.

In an embodiment, Group II/II+ extra heavy neutral oil base stocks have: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from about 250 cSt to about 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from about 15 cSt to about 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from about 80 to about 120; and/or a pour point, as determined by ASTM D97, of from about −50° C. to about −10° C.

Group II/II+ extra heavy neutral oil base stocks may be included in a gear oil composition at from about 25 wt. % to about 99 wt. %, including all wt. % values and subsets therebetween, based on the total weight of the gear oil composition (e.g., from about 25 wt. % to about 95 wt. %, from about 30 wt. % to about 90 wt. %, from about 35 wt. % to about 85 wt. %, from about 40 wt. % to about 80 wt. %, from about 45 wt. % to about 75 wt. %, or from about 60 wt. % to about 70 wt. %, or about 50 wt. % to about 85 wt. %, or about 60 wt. % to about 80 wt. %).

In some embodiments, Group II/II+ extra heavy neutral oil base stocks may be included in gear oil compositions at from about 5 wt % to about 89 wt %. %, including all wt. % values and subsets therebetween, based on the total weight of the gear oil composition (e.g., from about 20 wt. % to about 85 wt. %, from about 30 wt. % to about 85 wt. %, from about 40 wt. % to about 85 wt. %, from about 50 wt. % to about 85 wt. %, or from about 60 wt. % to about 85 wt. %).

Group V Oil Base Stocks

Group V oil base stocks may include, but are not limited to, an ester (including esters of a dibasic acid (e.g., phthalic, succinic, alkylsuccinic, alkenylsuccinic, maleic, azelaic, suberic, sebacic, fumaric or adipic acid (adipate), or linolic acid dimmer) and alcohol (e.g., butyl, hexyl, 2-ethylhexyl, dodecyl alcohol, ethylene glycol, diethylene glycol monoether or propylene glycol), and esters of a monocarboxylic acid of 5 to 18 carbon atoms and polyol (e.g., neopentyl glycol, trimethylolpropane (TMP), pentaerythritol, dipentaerythritol or tripentaerythritol)); a naphthalene compound (e.g., an alkylated naphthalene); other alkylated aromatic compounds; polyalkylene glycols (PAGs), esters thereof, and ethers thereof; phosphate esters, the like, and any combination thereof. In particular embodiments, the Group V additional oil base stocks may comprise a TMP ester, an adipate ester, an alkylated naphthalene, a PAG, and any combination thereof. In an embodiment, the Group V additional oil base stock is an adipate ester. Examples of suitable commercially available Group V additional oil base stocks include, but are not limited to, adipate esters (e.g., ditridecyl adipate, diisodecyl adipate, e.g., ESTEREX™ series, ExxonMobil Corporation) and alkylated naphthalene (e.g., SYNESSTIC™ series, ExxonMobil Corporation, such as SYNESSTIC™ 5 or SYNESSTIC™ 12).

In an embodiment, the Group V oil base stock comprises at least one oil base stock selected from the group consisting of alkylated aromatics.

In an embodiment, Group V oil base stocks comprise at least one oil base stock selected from the group consisting of an ester (e.g., an adipate ester), a naphthalene compound (e.g., an alkylated naphthalene compound), and any combination thereof. In an embodiment, the oil base stock comprises a Group V oil base stock which is an adipate ester. In an embodiment, the oil base stock comprises a Group V oil base stock present at from about 5 wt. % to about 40 wt. %, including all wt. % values and subsets therebetween, based on the total weight of the gear oil composition (e.g., from about 5 wt. % to about 10 wt. %, from about 5 wt. % to about 20 wt. %, from about 5 wt. % to about 30 wt. %, from about 10 wt. % to about 20 wt. %, from about 10 wt. % to about 30 wt. %, from about 10 wt. % to about 40 wt. %, from about 15 wt. % to about 20 wt. %, from about 15 wt. % to about 30 wt. %, from about 15 wt. % to about 40 wt. %, from about 20 wt. % to about 30 wt. %, from about 20 wt. % to about 40 wt. %, from about 30 wt. % to about 40 wt. %, or from about 20 wt. % to about 25 wt. %). In one embodiment, the Group V oil base stock is present at from about 10 wt. % to about 20 wt. %, based on the total weight of the gear oil composition.

For example, Group V oil base stocks may be present at from about 10 wt % to about 20 wt %, such as about 15 wt %.

Additional Oil Base Stocks

In addition to the primary oil base stocks, Group II/II+ extra heavy neutral oil base stocks and Group V oil base stocks, base oils may comprise various types and amounts of additional oil base stocks. When present, additional oil base stocks may be included in a gear oil composition at about 50 wt. % or less, including all wt. % values and subsets therebetween, based on the total weight of the Group II/II+ extra heavy neutral oil base stocks (e.g., about 45 wt. %, about 40 wt. % or less, about 35 wt. % or less, about 30 wt. % or less, about 25 wt. % or less, about 20 wt. % or less, about 15 wt. or less, or about 10 wt. % or less).

Additional oil base stocks may comprise one single additional oil base stock or two or more different additional oil base stocks. Additional oil base stocks may comprise fluids selected from API designated Group I oil base stocks, Group II/II+ oil base stocks (i.e., Group II oil base stocks, Group II+ oil base stocks, or any combination thereof), Group III/III+ oil base stocks (i.e., Group III oil base stocks, Group III+ oil base stocks, or any combination thereof), Group IV oil base stocks, or the like, or any combination thereof. Additional oil base stocks may include, but are not limited to, unrefined or refined crude oils, terpenes, mineral oils, synthetic hydrocarbons, naphthalenes, esters, the like, or any combination thereof.

Group I oil base stocks may comprise CORE™ series (ExxonMobil Corporation) (e.g., CORE™ 100, CORE™ 150, CORE™ 600, and CORE™ 2500). Group II/II+ oil base stocks may comprise viscosity grade classifications of light neutral, medium neutral, or heavy neutral. Examples of suitable commercially available light neutral and medium neutral Group II/II+ oil base stocks include, but are not limited to, the EHC™ series (ExxonMobil Corporation) (e.g., EHC™ 45, EHC™ 50, EHC™ 65, and EHC™ 110), Ultra-S® 2 (60 Neutral) (S-Oil Corporation), and the like.

Group III/III+ oil base stocks may include, but are not limited to, CTLs, GTLs, the like, and any combination thereof. An example of a suitable commercially available Group III/III+ oil base stock includes, but is not limited to, the ALTUM™ series (ExxonMobil, USA) (e.g., ALTUM™ 4 and ALTUM™ 6), the Qatar GTL QHVI™ series (Qatar Shell GTL Limited) (e.g., Qatar GTL QHVI™ 4 (e.g., GTL 4), Qatar GTL QHVI™ 8 (e.g., GTL 8), and the like).

Group IV oil base stocks may include various PAOs. PAOs for use in the base oil compositions are not considered to be particularly limited. PAOs may include, for example, light or heavy conventional PAOs (i.e., light PAOs have lower boiling points than heavy PAOs), metallocene PAOs (mPAOs), the like, and any combination thereof. PAOs are often referred to by their KV100 values (e.g., PAO 40 has a KV100 value of about 40 cSt, PAO 100 has a KV100 value of about 100 cSt). Examples of suitable commercially available typical PAO oil base stocks include, but are not limited to, the SPECTRASYN™ series PAOs (ExxonMobil Corporation) (e.g., SPECTRASYN™ 2, SPECTRASYN™ 2C, SPECTRASYN™ 4, SPECTRASYN™ 5, SPECTRASYN™ 6 (e.g., PAO 6), SPECTRASYN™ 8, SPECTRASYN™ 10, SPECTRASYN™ 40 (e.g., PAO 40), and SPECTRASYN™ 100 (e.g., PAO 100)). Examples of a suitable commercially available metallocene PAOs (mPAOs) include, but are not limited to, the SPECTRASYN ELITE™ series mPAOs (ExxonMobil Chemical) (e.g., SPECTRASYN ELITE™ 65, SPECTRASYN ELITE™ 150, and SPECTRASYN ELITE™ 300), the DURASYN® series (e.g., DURASYN® 180R (e.g., mPAO 100)).

As described above, the additional oil base stocks may additionally function as a Trim Stock. Examples of suitable Trim Stocks may include any low viscosity (“LS”) Group II-IV oil base stocks including, but not limited to, a light neutral or medium neutral Group II/II+ oil base stock, a low viscosity PAO (e.g., PAO 6, PAO 4) oil base stock, a low viscosity gas-to-liquid (GTL) oil base stock (e.g., GTL 4, GTL 8), and the like, and any combination thereof. Examples of suitable commercially available Trim Stocks for use in the present disclosure include, but are not limited to, EHC™ 50, ULTRA-S® 2 (60 Neutral) (S-Oil Corporation), SPECTRASYN™ 6 or SPECTRASYN™ 4, Qatar GTL QHVI™ 4 (Qatar Shell GTL Limited), or Qatar GTL QHVI™ 8 (Qatar Shell GTL Limited).

In an embodiment, the additional oil base stocks comprise a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of a polyalphaolefin (PAO) oil base stock, a metallocene PAO oil base stock, and any combination thereof. In an embodiment, the additional oil base stock comprises a Group IV oil base stock comprising a blend of two or more different PAO oil base stocks, such as, but not limited to, a blend of PAO 100 and PAO 40. In an embodiment, the additional oil base stock comprises a Group IV oil base stock present at less than about 50 wt. % or less, including all wt. % values and subsets therebetween, based on the total weight of the Group II/II+ extra heavy neutral oil base stock (e.g., about 10 wt. % or less, about 20 wt. % or less, about 30 wt. % or less, or about 40 wt. % or less).

In some embodiments, when present, Group IV oil base stocks may be included in gear oil compositions at from about 10 wt. % to about 84 wt %, including all wt. % values and subsets therebetween, based on the total weight of the gear oil composition (e.g., about 10 wt. % to about 75 wt %, about 10 wt. % to about 65 wt %, about 10 wt. % to about 55 wt %, about 10 wt. % to about 45 wt %, about 10 wt. % to about 40 wt %, about 10 wt. % to about 35 wt %, about 10 wt. % to about 30 wt %, about 10 wt. % to about 20 wt %, or about 10 wt. % to about 15 wt %). For example, Group IV oil base stocks may be included in gear oil compositions at about 20 wt % to about 84 wt % based on the total weight of the gear oil composition.

Suitable additional oil base stocks may have various rheological properties, as determined by any of the rheological testing methods suitable for Group II/II+ extra heavy neutral oil base stocks. In an embodiment, additional oil base stocks may have a KV40 of from about 10 cSt to about 2000 cSt, including all cSt values and subsets therebetween. In an embodiment, additional oil base stocks may have a KV100 of from about 1.0 cSt to about 300 cSt, including all cSt values and subsets therebetween. In an embodiment, additional oil base stocks may have a VI of from about 60 to about 300, including all viscosity index values and subsets therebetween.

Suitable additional oil base stocks may have various pour points. In an embodiment, additional oil base stocks may have a pour point value of from about −80° C. to −20° C., including all ° C. values and subsets therebetween (e.g., from about −60° C. to about −25° C., from about −50° C. to about −30° C., from about −40° C. to about −35° C.).

Suitable additional oil base stocks may have various oxidation stability values, as determined by any one of the oxidation stability tests suitable for Group II/II+ extra heavy neutral oil base stocks. In an embodiment, additional oil base stocks may have an ASTM D2893 (run at 121 C) oxidation test KV100% increase of about 10% or less, including all % values and subsets therebetween (e.g., about 10%, about 9.9% or less, about 9.8% or less, about 9.5% or less, about 8% or less, about 7% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less, or from about 1% to about 9.9%.

Additives for Gear Oil Compositions

Gear oil compositions of the present disclosure may comprise one or more additives (e.g., additives related to solubility, friction, corrosion, oxidation stability, cleanliness, defoaming, viscosity, wearing, low temperature fluidity, the like, and any combination thereof, to satisfy diversified characteristics). In an embodiment, gear oil compositions comprise a performance additive package comprising two or more different additives. In an embodiment, gear oil compositions comprise from about 1 wt. % to about 5 wt. %, including all wt. % values and subsets therebetween, of a performance additive package (e.g., from about 1 wt. % to about 4.5 wt. %, from about 1.5 wt. % to about 4 wt. %, from about 2 wt. % to about 3.5 wt. %, from about 1 wt. % to about 3 wt. %, from about 2 wt. % to about 4 wt. %, or from about 3 wt. % to about 5 wt. %), based on the total weight of the gear oil composition. In an embodiment, gear oil compositions comprise from about 1 wt. % to about 3 wt. % of a performance additive package, based on the total weight of the gear oil composition.

In an embodiment, a gear oil composition comprises from about 95 wt. % to about 99 wt. %, including all wt. % values and subsets therebetween, of a base oil, and/or from about 1 wt. % to about 5 wt. %, including all wt. % values and subsets therebetween, of a performance additive package, based on the total weight of the gear oil composition.

Additives for use in the gear oil compositions may comprise an antioxidant, an antiwear agent, an antifoaming agent, a demulsifier, a friction modifier, a corrosion inhibitor (e.g., a copper corrosion inhibitor, a rust inhibitor, a metal passivator, or the like), a detergent, a dispersant, a viscosity index improver, a pour point improver, the like, and any combination thereof. The additives for use in the gear oil compositions may be metal-containing (e.g., zinc-containing), metal-free (e.g., zinc-free), or ash-free. In an embodiment, the additives are metal-free and ash-free.

Suitable antioxidants may include, but are not limited to, amine-based antioxidants (e.g., alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-x-naphthylamine); phenol-based antioxidants (e.g., 4,4′-methylenebis-(2,6-di-t-butylphenol), and 2,6-di-t-butyl phenol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate); sulfur-based antioxidants (e.g., dilauryl-3,3′-thiodipropionate); zinc dithiophosphate, the like, and any combination thereof.

Suitable antiwear agents may include, but are not limited to, amine phosphates, thiadiazole derivatives, borated esters, borated amines, zinc dialkyldithiophosphates, zinc dialkyldithiocarbamates, sulfurized esters, sulfurized olefins, and the like. Antiwear agents prevent the wearing away of the metal surface. A more severe form of wear involves the welding and ripping away of two metal surfaces in contact. This may be referred to as scuffing, and is prevented by anti-scuffing additives, sometimes referred to as extreme pressure or EP additives. EP additives are more reactive and may contain a higher level of sulfur. Examples are sulfurized isobutylene and di-alkylpolysulfide.

Suitable antifoaming agents may include, but are not limited to, dimethyl polysiloxane, polyacrylate and a fluorine derivative thereof, perfluoropolyether, the like, and any combination thereof.

Suitable demulsifiers may include, but are not limited to, polyethers, fatty acid esters, alkoxylated ethers and glycol ethers.

Suitable friction modifiers may include, but are not limited to, an organomolybdenum-based compound, fatty acid, higher alcohol, fatty acid ester, oil/fat, amine, polyamide, sulfide ester, phosphoric acid ester, acid phosphoric acid ester, acid phosphorous acid ester, amine salt of phosphoric acid ester, the like, and any combination thereof.

Suitable corrosion inhibitors may include a copper corrosion inhibitor, a rust inhibitor, the like, and any combination thereof. The corrosion inhibitor may include, but is not limited to, a fatty acid, alkenylsuccinic acid half ester, fatty acid soap, alkylsulfonate, polyhydric alcohol/fatty acid ester, fatty acid amine, oxidized paraffin, and alkylpolyoxyethylene ether, the like, and any combination thereof. Rust inhibitors may include calcium/sodium sulfonates and carboxylates, amine phosphates, zinc naphthenates, and various succinimides. The corrosion inhibitor may include a metal passivator. Suitable metal passivators may include, but are not limited to, derivatives of tolyltriazole (TTZ), ashless or metal-containing thiadiazole compounds.

Suitable dispersants may include, but are not limited to, an ashless dispersant. Ashless dispersants may include, but are not limited to, those based on polybutenyl succinic acid imide, polybutenyl succinic acid amide, benzylamine, succinic acid ester, succinic acid ester-amide and a zinc or boron derivative thereof, the like, and any combination thereof.

Suitable viscosity index improvers may include, but are not limited to, polyisobutylene (PIB), polymethacrylate (PMA) (e.g., polyalkylmethacrylates), olefin copolymers (OCP) (e.g., ethylene-propylene copolymers, ethylene-propylene diene-modified copolymers (EPDMs), and the like), styrene maleic anhydride ester copolymers (Styrene Esters), hydrogenated styrene diene (HSD) copolymers (e.g., styrene-ethylene/butylene-styrene copolymer (SEBS), styrene-isoprene, and the like), radial isoprene polymers/copolymers, the like, and any combination thereof. An example of a suitable commercially available viscosity index improver includes, but is not limited to, Viscoplex® 8-219 (Evonik). A gear oil composition may comprise a viscosity index improver as part of a performance additive package or in addition to a performance additive package (e.g., an additional oil base stock may comprise the viscosity index improver).

Suitable pour point improvers may include a pour point depressant. Pour point depressants may include, but are not limited to, ethylene/vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkyl styrene, the like, and any combination thereof. An example of a suitable commercially available viscosity index improver includes, but is not limited to, Viscoplex® 1-333 (Evonik).

In an embodiment, the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof. In an embodiment, the gear oil compositions comprise from about 1 wt. % to about 5 wt. %, including all wt. % values and subsets therebetween, of the performance additive package, based on the total weight of the gear oil composition (e.g., from about 2 wt. % to about 5 wt. %, from about 2 wt. % to about 4 wt. %, from about 2 wt. % to about 3 wt. %, from about 3 wt. % to about 5 wt. %, from about 3 wt. % to about 4 wt. %, from about 4 wt. % to about 5 wt. %). In an embodiment, the performance additive package is present at from 2 wt. % to about 4 wt. %.

Gear Oil Methods

In an aspect, the present disclosure provides gear oil methods. In an embodiment, the present disclosure provides methods of making gear oil compositions. Methods of making a gear oil composition of the present disclosure may comprise providing a base oil. In an embodiment, methods of making a gear oil composition further comprise providing a performance additive package. In an embodiment, methods of making a gear oil composition further comprise blending the base oil and the performance additive package, thereby forming the gear oil composition.

In certain embodiments, gear oil compositions of the present disclosure are formed by mixing the various components of the various base oil stocks and the additives according to one or more methods of the present disclosure. In certain embodiments, the mixture may be heated, such as in a reaction vessel. In certain embodiments, the mixture may be homogenized to ensure well-mixed and evenly dispersed components. If heated, the mixture is cooled after homogenization.

Further, in one or more embodiments, at least two of the Group II/II+ extra heavy neutral oil base stock, the Group V oil base stock, and, if present, the additional oil base stock are pre-blended. Moreover, two or more pre-blends may be themselves blended to achieve a lower viscosity index and a lower kinematic viscosity (@40° C. and @100° C.) base oil compared to either of the pre-blends alone. It is to be noted that alternatively at least the Group II/II+ extra heavy neutral oil base stock and, if present, the additional oil base stock may be pre-blended without blending with additional pre-blends.

To facilitate a better understanding of the embodiments of the present disclosure, the following examples of representative embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the disclosure.

Example Embodiments

The present disclosure is further directed to the following non-limiting embodiments.

Embodiment 1. A gear oil composition, comprising: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein the gear oil composition exhibits one or more of the following, as compared to a corresponding gear oil composition wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

Embodiment 2. A gear oil composition, comprising: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

Embodiment 3. The gear oil composition of Embodiment 1 or Embodiment 2, wherein the Group II/II+ extra heavy neutral oil base stock has: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 80 to 120; and/or a pour point, as determined by ASTM D97, of from −50° C. to −10° C.

Embodiment 4. The gear oil composition of any one of Embodiments 1-3, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

Embodiment 5. The gear oil composition of any one of Embodiments 1-4, wherein the Group V oil base stock is present at from 10 weight percent (wt. %) to 20 wt. %, based on the total weight of the gear oil composition.

Embodiment 6. The gear oil composition of any one of Embodiments 1-5, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

Embodiment 7. The gear oil composition of any one of Embodiments 1-6, wherein the gear oil composition comprises from 95 weight percent (wt. %) to 99 wt. %, of the base oil, and/or from 1 wt. % to 5 wt. %, of the performance additive package, based on the total weight of the gear oil composition.

Embodiment 8. The gear oil composition of any one of Embodiments 1-7, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

Embodiment 9. The gear oil composition of Embodiment 8, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof, and/or wherein the additional oil base stock comprises a Group IV oil base stock present at 50 weight percent (wt. %) or less, based on the total weight of the Group II/II+ extra heavy neutral oil base stock

Embodiment 10. The gear oil composition of any one of Embodiments 1-9 wherein the gear oil composition exhibits one or more of the following: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; and a viscosity index (VI), as determined by ASTM D2270, of from 90 to 160.

Embodiment 11. The gear oil composition of any one of Embodiments 1-10, wherein the gear oil composition exhibits a property selected from the group consisting of: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150, and any combination thereof.

Embodiment 12. The gear oil composition of any one of Embodiments 1-11, wherein the gear oil composition exhibits one or more of the following: a pour point, as determined by ASTM D97, of from −60° C. to −30° C.; and a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less.

Embodiment 13. The gear oil composition of any one of Embodiments 1-12, wherein the gear oil composition exhibits a property selected from the group consisting of: a pour point, as determined by ASTM D97, of from −50° C. to −30° C.; a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less, and any combination thereof.

Embodiment 14. A method for producing a gear oil composition, the method comprising: providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; optionally, providing a performance additive package; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting one or more of the following, as compared to a corresponding gear oil composition wherein 50 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; and equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893.

Embodiment 15. A method for producing a gear oil composition, the method comprising: providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; optionally, providing a performance additive package; and optionally, blending the base oil with a performance additive package, thereby forming a gear oil composition exhibiting, as compared to a corresponding gear oil composition wherein 40 weight percent (wt. %) or more of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893, and any combination thereof.

Embodiment 16. The method of Embodiment 14 or Embodiment 15, wherein the Group II/II+ extra heavy neutral oil base stock has: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 80 to 160; and/or a pour point, as determined by ASTM D97, of from −50° C. to −10° C.

Embodiment 17. The method of any one of Embodiments 14-16, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

Embodiment 18. The method of any one of Embodiments 14-17, wherein the Group V oil base stock is present at from 10 weight percent (wt. %) to 20 wt. %, based on the total weight of the gear oil composition.

Embodiment 19. The method of any one of Embodiments 14-18, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

Embodiment 20. The method of any one of Embodiments 14-19, wherein the gear oil composition comprises from 95 weight percent (wt. %) to 99 wt. %, of the base oil, and/or from 1 wt. % to 5 wt. %, of the performance additive package, based on the total weight of the gear oil composition.

Embodiment 21. The method of any one of Embodiments 14-20, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

Embodiment 22. The method of Embodiment 21, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof, and/or wherein the additional oil base stock comprises a Group IV oil base stock present at 50 weight percent (wt. %) or less, based on the total weight of the Group II/II+ extra heavy neutral oil base stock

Embodiment 23. The method of any one of Embodiments 14-22, wherein the gear oil composition exhibits one or more of the following: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; and a viscosity index (VI), as determined by ASTM D2270, of from 90 to 160.

Embodiment 24. The method of any one of Embodiments 14-23, wherein the gear oil composition exhibits a property selected from the group consisting of: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150; and any combination thereof.

Embodiment 25. The method of any one of Embodiments 14-24, wherein the gear oil composition exhibits one or more of the following: a pour point, as determined by ASTM D97, of from −60° C. to −30° C.; and a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less.

Embodiment 26. The method of any one of Embodiments 14-25, wherein the gear oil composition exhibits a property selected from the group consisting of: a pour point, as determined by ASTM D97, of from 60° C. to 30° C.; a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less, and any combination thereof.

Embodiment 27. A gear oil composition, comprising: a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and a performance additive package; wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, determined by ASTM D130; equivalent or reduced rust formation, determined by ASTM D665; equivalent or reduced pour point, determined by ASTM D97; equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

Embodiment 28. The gear oil composition of Embodiment 27, wherein the Group II/II+ extra heavy neutral oil base stock has: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 80 to 120; and/or a pour point, as determined by ASTM D97, of from 50° C. to 10° C.

Embodiment 29. The gear oil composition of Embodiment 27 or Embodiment 28, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

Embodiment 30. The gear oil composition of any one of Embodiments 27-29, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of alkylated aromatics.

Embodiment 31. The gear oil composition of any one of Embodiments 27-30, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

Embodiment 32. The gear oil composition of any one of Embodiments 27-31, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

Embodiment 33. The gear oil composition of Embodiment 32, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof.

Embodiment 34. The gear oil composition of any one of Embodiments 27-33, wherein the Group IV oil base stock is present in the gear oil composition at from about 10 wt % to about 84 wt %.

Embodiment 35. The gear oil composition of any one of Embodiments 27-34, wherein the gear oil composition exhibits a property selected from the group consisting of: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150; and any combination thereof.

Embodiment 36. The gear oil composition of any one of Embodiments 27-35, wherein the gear oil composition exhibits a property selected from the group consisting of: a pour point, as determined by ASTM D97, of from 40° C. to 20° C.; a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less; and any combination thereof.

Embodiment 37. A method for producing a gear oil composition, the method comprising: providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock; providing a performance additive package; and blending the base oil with the performance additive package, thereby forming a gear oil composition wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; the performance additive package is present in the gear oil composition at from about 1 wt % to about 5 wt %; and the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: equivalent or reduced copper corrosion, as determined by ASTM D130; equivalent or reduced rust formation, as determined by ASTM D665; equivalent or reduced pour point, as determined by ASTM D97; equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and any combination thereof.

Embodiment 38. The method of Embodiment 37, wherein the Group II/II+ extra heavy neutral oil base stock has: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 80 to 160; and/or a pour point, as determined by ASTM D97, of from 51° C. to 12° C.

Embodiment 39. The method of Embodiment 37 or Embodiment 38, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

Embodiment 40. The method of any one of Embodiments 37-39, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of alkylated aromatics.

Embodiment 41. The method of any one of Embodiments 37-40, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

Embodiment 42. The method of any one of Embodiments 37-41, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

Embodiment 43. The method of Embodiment 42, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof.

Embodiment 44. The method of any one of Embodiments 37-43, wherein the Group IV oil base stock is present in the gear oil composition at from about 10 wt % to about 84 wt %.

Embodiment 45. The method of any one of Embodiments 37-44, wherein the gear oil composition exhibits a property selected from the group consisting of: a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt; a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt; a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150; and any combination thereof.

Embodiment 46. The method of any one of Embodiments 37-45, wherein the gear oil composition exhibits a property selected from the group consisting of: a pour point, as determined by ASTM D97, of from 40° C. to 20° C.; a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less; and any combination thereof.

EXAMPLES

Example 1

Group IV (PAO) based industrial lubricants are expected to have enhanced performance properties over the same lubricants formulated with Group II oil base stocks. It has been found surprisingly that when either fully or partially replacing PAO of a gear oil composition with Group II/II+ extra heavy neutral oil base stock (e.g., EHC 340 MAX™ ExxonMobil Corporation), equivalent or improved results are exhibited in a wide range of lubricant performance tests. These tests cover many performance areas, including: copper corrosion, rust, water separability (demulsibility), pour point, and oxidation stability and deposits.

Especially surprising are the ASTM D97 pour point results being equivalent (test is ±3° C.), as PAO is known to have exceptionally low temperature performance. Table 1 below gives the components of the gear oil compositions tested, including a control example (CE) and two inventive examples (IE1 and IE2).

TABLE 1
Gear Oil Composition Components	CE	IE1	IE2
Group V: Adipate Ester/ESTEREX ™ A51	15	15	15
Group IV: PAO 40/SPECTRASYN ™ 40	68.2	34.1	—
Group IV: PAO 100/SPECTRASYN ™ 100	14	7	—
Group II/II+ Extra Heavy Neutral: EHC 340	—	41.1	82.2
MAX ™
Performance Additive Package	2.8	2.8	2.8
Total	100	100	100

Optionally, Group V oil base stocks can be used. These include, but are not limited to, esters (e.g., adipate esters) and alkylated aromatics (e.g., alkylated naphthalene compounds). The Group V oil base stocks can be added at 10-20%.

A typical additive package for a gear oil may contain: an antioxidant, an antiwear agent, an antifoam agent, a demulsifier, an antirust agent, and a metal passivator. The package can range from 1%-5%, optimally 2%-4%.

Table 2 below shows the results of the gear oil compositions tested.

TABLE 2
Category	Number	Unit	CE	IE1	IE2
Viscosity	ASTM D445, KV40	cSt	274.6	264.4	269.5
	ASTM D224, KV100	cSt	31.52	26.76	23
	ASTM D2270, VI	—	155.9	132.2	105.2
Pour Point	ASTM D97, Manual Method	° C.	−51	−51	−48
Copper Corrosion	ASTM D130, 212° F., 3 hrs	Rating	1A	1A	1A
Rust Formation	ASTM D665, Synth. Seawater,	Rating	PASS	PASS	PASS
	1 specimen, 140° F., 24 hrs
Oxidation	ASTM D2272, RPVOT	min	683	681	668
	ExxonMobil B10, KV100	%	7.8	6.6	5.7
	Increase, 163° C., 120 hr
	ASTM D2893/KV100 Increase	%	2.7	2.3	8.8
	121° C., 13 days
	ASTM D2893/Sludge, mg,	mg	83.93	53.70	87.9
	121° C., 13 days
	ASTM D2893/D91 Precip. #	mL	<0.025	<0.025	<0.025
	121° C., 13 days
	ASTM D2893/Acid # Increase	mg	−0.22	−0.19	−0.27
	121° C., 13 days	KOH/g
Demulsibility	ASTM D1401, Time to 37 ml	min	10	10	10
	H20, 82° C.
	ASTM D1401,	mL	42-38-0	41-39-0	41-39-0
	Oil-Water-Emulsion, 82° C.
	ASTM D2711, Tot. Free H20	mL	83.0	82.5	83.1
	82° C.,
	ASTM D2711, Tot. Emulsion	mL	0	0	0
	82° C.
	ASTM D2711, Water in Oil,	%	0.4	0.4	0.4
	82° C.
Antiwear	ASTM D2783, Weld Load	kg	200	200	200
	ASTM D2783, Last	kg	126	126	126
	Non-Seizure Load
	ASTM D4172, Scar Diameter,	mm	0.2	0.3	0.3
	20 kg, 1800 rpm, 1 hr, 54° C.

Improved oxidation stability can lead to longer oil life in severe oil service. Table 2 shows reduced KV100% increase, according to the ASTM D2893 oxidation test inventive examples with EHC 340 MAX™ (ExxonMobil Corporation) vs the PAO comparative examples, run at the severe conditions of 121° C. for 13 days. This is very unexpected as PAO has exceptional oxidation stability and would be expected to outperform EHC 340 MAX™.

In summary, the present example describes a method to achieve equivalent or improved performance by substituting the Group IV oil base stock of a gear oil composition with a Group II/II+ extra heavy neutral oil base stock, and compositions to achieve this.

Example 2

Further studies of gear oil compositions were performed. Table 3 below gives the components of a control example (CE), and six inventive examples (IE1 to IE6).

TABLE 3
Gear Oil Composition
Components	CE	IE3	IE4	IE1	IE5	IE6	IE2
Group V: Adipate Ester/	15	15	15	15	15	15	15
ESTEREX ™ A51
Group IV: PAO 40/	68.2	52.2	42.2	34.1	25.1	15	0
SPECTRASYN ™ 40
Group IV: PAO 100/	14	10	10	7	5	5	0
SPECTRASYN ™ 100
Group II/II+ Extra	0	20	30	41.1	52.12	62.22	82.2
Heavy Neutral:
EHC 340 MAX ™
Performance	2.8	2.8	2.8	2.8	2.78	2.78	2.8
Package Additive
Total	100	100	100	100	100	100	100

The performance additive package contained an antioxidant, an antiwear agent, an antifoam agent, a demulsifier, and a metal passivator.

Viscosity properties determined for the control example and the inventive examples were KV40, determined by ASTM D445; KV100, determined by ASTM D445; and VI, determined by ASTM D2270.

Pour point for the control example and the inventive examples was determined by ASTM D5949.

Copper corrosion for the control example and the inventive examples was determined by ASTM D130, 212° F., 3 hrs (Rating).

Rust test for the control example and the inventive examples was determined by ASTM D665, Seawater, 1 specimen, 140° F., 24 hrs (Rating).

Oxidation properties determined for the control example and the inventive examples were RPVOT, determined by ASTM D2272; KV100 Increase, determined by ExxonMobil B10, 163° C., 120 hr; KV100 Increase, determined by ASTM D2893, 121° C., 13 days; Sludge, determined by ASTM D2893, 121° C., 13 days; Precipitation Number, determined by ASTM D2893/D91, 121° C., 13 days; and Acid Number Increase, determined by ASTM D2893, 121° C., 13 days.

Demulsibility properties determined for the control example and the inventive examples were Time to 37 ml H2O, determined by ASTM D1401, 82° C.; Oil-Water-Emulsion, determined by ASTM D1401, 82° C.; Total Free H2O, determined by ASTM D2711, 82° C.; Total Emulsion, determined by ASTM D2711, 82° C.; and Water in Oil, determined by ASTM D2711.

Antiwear properties determined for the control example and the inventive examples were Weld Load, determined by ASTM D2783; Last Non-Seizure Load, determined by ASTM D2783; and Scar Diameter, determined by ASTM D4172, 20 kg, 1800 rpm, 1 hr, 54° C.

Table 4 below gives the tests and results for gear oil compositions tested.

TABLE 4
Category	Test	CE	IE3	IE4	IE1	IE5	IE6	IE2
Viscosity	ASTM D445, KV40 (cSt)	274.6	268.5	279	264.4	262	270.4	269.5
	ASTM D445, KV100 (cSt)	31.52	28.26	27.73	26.76	25.15	24.64	23
	ASTM D2270, VI	155.9	140	132	132.2	122	115	105.2
Pour Point	ASTM D5949 (° C.)	−36	−36	−33	−36	−33	−33	−30
Copper	ASTM D130, 212° F., 3 hrs	1A	1A	1A	1A	1A	1A	1A
Corrosion	(Rating)
Rust Test	ASTM D665, Seawater, 1	PASS	PASS	PASS	PASS	PASS	PASS	PASS
	specimen, 140° F., 24 hrs
	(Rating)
Oxidation	ASTM D2272, RPVOT	866	816	908	883	787	764	758
	(min)
	ExxonMobil B10, KV100,	7.8	8.5	7.2	6.6	7.2	6.8	5.7
	Increase, 163° C., 120 hr
	(%)
	ASTM D2893/KV100	2.7	3.14	3.28	2.3	2.7	3	1.7
	Increase 121° C., 13 days
	(%)
	ASTM D2893/Sludge,	83.93	31.5	39.2	53.7	53.9	154.7	87.9
	121° C., 13 days (mg)
	ASTM D2893/D91 Precip.	<0.025	<0.025	<0.025	<0.025	<0.025	<0.025	<0.025
	Number, 121° C., 13 days
	ASTM D2893/Acid	−0.22	0.2	0.2	−0.19	0.2	0.2	−0.27
	Number Increase, 121° C.,
	13 days (Δmg KOH/g)
Demulsibility	ASTM D1401/Time to 37	10	10	10	10	10	10	10
	ml, H2O, 82° C. (min)
	ASTM D1401, Oil-Water-	42-38-0	42-38-0	41-39-0	41-39-0	43-37-0	42-38-0	41-39-0
	Emulsion, 82° C. (mL)
	ASTM D2711, Tot. Free	83	82.5	82.8	82.5	82.8	82.3	83.1
	H2O, 82° C., (mL)
	ASTM D2711, Tot.	0	0	0	0	0	0	0
	Emulsion, 82° C. (mL)
	ASTM D2711, Water in	0.4	0.5	0.45	0.4	0.5	0.45	0.4
	Oil (%)
Antiwear	ASTM D2783, Weld Load	200	200	200	200	200	200	200
	(kgf)
	ASTM D2783, Last Non-	126	100	126	126	100	80	126
	Seizure Load (kgf)
	ASTM D4172, Scar	0.2	0.3	0.25	0.3	0.35	0.34	0.3
	Diameter, 20 kg, 1800 rpm,
	1 hr, 54° C. (mm)

While various embodiments have been shown and described herein, modifications may be made by one skilled in the art without departing from the scope of the present disclosure. The embodiments described herein are exemplary only and are not intended to be limiting. Many variations, combinations, and modifications of the embodiments disclosed herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims.

Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples and configurations disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative examples disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present disclosure. The disclosure illustratively disclosed herein suitably may be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about A to about B,” or, equivalently, “from approximately A to B,” or, equivalently, “from approximately A-B”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the incarnations of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

One or more illustrative incarnations incorporating one or more disclosed elements are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity. It is understood that in the development of a physical embodiment incorporating one or more elements of the present disclosure, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and from time to time. While a developer's efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art and having benefit of this disclosure.

Claims

1. A gear oil composition, comprising:

a performance additive package present in the gear oil composition at from about 1 wt % to about 5 wt %;

a base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock, and wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %; and,

the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: (i) equivalent or reduced copper corrosion, determined by ASTM D130; (ii) equivalent or reduced rust formation, determined by ASTM D665; (iii) equivalent or reduced pour point, determined by ASTM D97; (vi) equivalent or increased demulsibility, determined by ASTM D1401 or ASTM D2711; (v) equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; (vi) equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and (vii) any combination of (i) through (vi).

2. The gear oil composition of claim 1, wherein the Group II/II+ extra heavy neutral oil base stock has:

a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt;

a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt;

a viscosity index (VI), as determined by ASTM D2270, of from 80 to 120; and/or

a pour point, as determined by ASTM D97, of from −50° C. to −10° C.

3. The gear oil composition of claim 1, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

4. The gear oil composition of claim 1, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of alkylated aromatics.

5. The gear oil composition of claim 1, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

6. The gear oil composition of claim 1, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

7. The gear oil composition of claim 6, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof.

8. The gear oil composition of claim 7, wherein the Group IV oil base stock is present in the gear oil composition at from about 10 wt % to about 84 wt %.

9. The gear oil composition of claim 1, wherein the gear oil composition exhibits a property selected from the group consisting of:

a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt;

a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt;

a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150; and

any combination thereof.

10. The gear oil composition of claim 1, wherein the gear oil composition exhibits a property selected from the group consisting of:

a pour point, as determined by ASTM D97, of from −40° C. to −20° C.;

a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less; and

any combination thereof.

11. A method for producing a gear oil composition, the method comprising:

providing a base oil for a gear oil composition, the base oil comprising a Group II/II+ extra heavy neutral oil base stock and a Group V oil base stock;

providing a performance additive package present in the gear oil composition at from about 1 wt % to about 5 wt %; and

blending the base oil with the performance additive package, thereby forming a gear oil composition wherein: the Group II/II+ extra heavy neutral oil base stock is present in the gear oil composition at from about 5 wt % to about 89 wt %; the Group V oil base stock is present in the gear oil composition at from about 10 wt % to about 20 wt %;

the gear oil composition exhibits, as compared to a corresponding gear oil composition wherein 100% of the Group II/II+ extra heavy neutral oil base stock is replaced by a Group IV oil base stock, a property selected from the group consisting of: (i) equivalent or reduced copper corrosion, as determined by ASTM D130; (ii) equivalent or reduced rust formation, as determined by ASTM D665; (iii) equivalent or reduced pour point, as determined by ASTM D97; (vi) equivalent or increased demulsibility, as determined by ASTM D1401 or ASTM D2711; (v) equivalent or decreased wearing, determined by ASTM D2783 or ASTM D4172; (vi) equivalent or reduced oxidation, as determined by ExxonMobil B10 oxidation test or ASTM D2272 or ASTM D2893; and (vii) any combination of (i) through (vi).

12. The method of claim 11, wherein the Group II/II+ extra heavy neutral oil base stock has:

a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 250 cSt to 600 cSt;

a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 15 cSt to 70 cSt;

a viscosity index (VI), as determined by ASTM D2270, of from 80 to 120; and/or

a pour point, as determined by ASTM D97, of from −50° C. to −10° C.

13. The method of claim 11, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of esters, naphthalene compounds, polyoxyalkylene glycols (PAGs), esters thereof, ethers thereof, phosphates, and any combination thereof.

14. The method of claim 11, wherein the Group V oil base stock comprises at least one oil base stock selected from the group consisting of alkylated aromatics.

15. The method of claim 11, wherein the performance additive package comprises at least one additive selected from the group consisting of antioxidants, antiwear agents, antifoaming agents, demulsifiers, metal passivators, and any combination thereof.

16. The method of claim 11, wherein the base oil further comprises at least one additional oil base stock selected from a group consisting of Group II oil base stocks, Group II+ oil base stocks, Group III oil base stocks, Group III+ oil base stocks, Group IV oil base stocks, and any combination thereof.

17. The method of claim 16, wherein the additional oil base stock comprises a Group IV oil base stock comprising at least one oil base stock selected from the group consisting of conventional polyalphaolefin (PAO) oil base stocks, metallocene PAO oil base stocks, and any combination thereof.

18. The method of claim 17, wherein the Group IV oil base stock is present in the gear oil composition at from about 10 wt % to about 84 wt %.

19. The method of claim 11, wherein the gear oil composition exhibits a property selected from the group consisting of:

a kinematic viscosity at 40° C. (KV40), as determined by ASTM D445, of from 200 cSt to 700 cSt;

a kinematic viscosity at 100° C. (KV100), as determined by ASTM D445, of from 10 cSt to 50 cSt;

a viscosity index (VI), as determined by ASTM D2270, of from 120 to 150; and

any combination thereof.

20. The method of claim 11, wherein the gear oil composition exhibits a property selected from the group consisting of:

a pour point, as determined by ASTM D97, of from −40° C. to −20° C.;

a kinematic viscosity at 100° C. (KV100) percent (%) increase, as determined by ExxonMobil B10 oxidation test, at 163° C. and 120 hours, or ASTM D2893, of 7% or less; and

any combination thereof.