OXIDATIVE STABILITY

TECHNICAL FIELD

This application is directed to a SAE 15W-30 lubricating oil composition having improved oxidative stability that is made using two different grades of Group II base oil, a detergent inhibitor additive package, a Total Base Number (TBN) booster, and a viscosity modifier.

BACKGROUND

Lubricating oil compositions are needed that meet modern performance specifications and that show improved performance in oxidative stability and other tests.

A SAE 15W-30 lubricating oil composition can be a lower-cost alternative to SAE 10W-30 lubricating oil compositions. In one embodiment, a SAE 15W-30 lubricating oil composition can provide similar fuel economy benefits as a SAE 10W-30 lubricating oil composition, but with enhanced engine wear protection due to the SAE 15W-30 lubricating oil composition having a base oil blend viscosity that is almost as high as a SAE 15W-40 lubricating oil composition.

SUMMARY

This application provides a lubricating oil composition, comprising:

a. a first Group II base oil having a kinematic viscosity at 100°C from 5.0 to 8.0 mm ² /s;

b. a second Group II base oil having a second kinematic viscosity at 100°C from 10 to 14 mm ² /s;

c. a detergent inhibitor additive package designed to meet an API CJ-4 service category;

d. 0.50 to 4.95 wt % of a viscosity modifier; wherein the lubricating oil composition has an SAE 15W-30 viscosity grade by SAE J300, a TBN from 8.55 to 1 1.00 mg KOH/g by ASTM D2896-1 1; and wherein the lubricating oil composition provides an Induction Time in a Caterpillar Micro-Oxidation Test from 270 to 450 minutes.

This application also provides a process for making a lubricating oil composition, comprising: a. blending a first Group II base oil having a kinematic viscosity at 100°C from 5.0 to 8.0 mm ² /s with a second Group II base oil having a second kinematic viscosity at 100°C from 10 to 14 mm ² /s to make a blended base oil mixture having a blended base oil kinematic viscosity at 100°C from 6.0 mm ² /s to 7.3 mm ² /s; and b. adding to the blended base oil mixture: i. a detergent inhibitor additive package designed to meet an API CJ-4

service category; and

ii. 0.5 to 4.95 wt% of a viscosity modifier, to make the lubricating oil

composition; wherein the lubricating oil composition has an SAE 15W-30 viscosity grade by SAE J300, a TBN from 8.55 to 11.00 mg KOH/g by ASTM D2896-11 ; and wherein the lubricating oil composition provides an Induction Time in a Caterpillar Micro-Oxidation Test from 270 to 450 minutes.

This application also provides a method of operating an engine, comprising lubricating an engine with a lubricating oil composition comprising:

a. a first Group II base oil having a kinematic viscosity at 100°C from 5.0 to 8.0 mm2/s;

b. a second Group II base oil having a second kinematic viscosity at 100°C from 10 to 14 mm ² /s;

c. a detergent inhibitor additive package designed to meet an API CJ-4 service category; and

d. 0.50 to 4.95 wt % of a viscosity modifier.

The present invention may suitably comprise, consist of, or consist essentially of, the elements in the claims, as described herein.

GLOSSARY

"Base oil" refers to a hydrocarbon fluid to which other oils or substances are added to produce a lubricant. "Lubricant" refers to substances (usually a fluid under operating conditions) introduced between two moving surfaces so to reduce the friction and wear between them.

"Group II base oil" refers to a base oil which contains greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and has a viscosity index greater than or equal to 80 and less than 120 using the American Society for Testing and Materials (ASTM) methods specified in Table E-l of American Petroleum Institute Publication 1509 (REV:01-SEP- 201 1). ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards.

"Group 11+ base oil" refers to a Group II base oil having a viscosity index greater than or equal to 110 and less than 120.

"Group I, II, III, IV, and V base oils" are defined in Table E-l of American Petroleum Institute Publication 1509 (REV:01-SEP-201 1)

"Kinematic viscosity" refers to the ratio of the dynamic viscosity to the density of a material at the same temperature and pressure. Kinematic viscosity (KV) is measured at a defined temperature (e.g., 100°C) by ASTM D445-12. Shorthand for kinematic viscosity at a defined temperature may be expressed as KV100 or KV40, for example.

"Viscosity index" (VI) is an empirical, unit-less number indicating the effect of temperature change on the kinematic viscosity of the base oil or lubricant. A higher VI indicates a smaller decrease in kinematic viscosity with increasing temperature. VI is measured according to ASTM D2270-10 ^El .

"Detergent inhibitor (DI) additive package" refers to a carefully blended mixture of additives used to formulate lubricating oil compositions that will meet certain performance criteria. DI additive packages are commercially available from a number of additive companies. Examples of companies that supply these DI additive packages include Oronite, Lubrizol, and Infineum.

"Succinimide" refers to the product of a reaction of an alkenyl substituted succinic acid or anhydride with a nitrogen-containing compound. "Succinimide dispersants" are referred to as such since they normally contain nitrogen largely in the form of imide functionality, although the amide functionality may be in the form of amine salts, amides, imidazolines, as well as mixtures thereof. Procedures for preparing succinimide dispersants are described, for example, in U.S. Pat. Nos. 3,172,892; 3,219,666; 3,272,746; 4,234,435; 6, 165,235; and 6,440,905. "Trim stock" refers to a base oil that may be blended with two or more other base oils, in an amount less than the two or more other base oils, so as to bring a low-temp cranking viscosity and NOACK volatility of a blended base oil mixture into a range to meet SAE J300 and API CJ-4 requirements. A trim stock, for example, may be a Group II, a Group II+, a Group III, a Group IV, or a Group V base oil. The use and selection of a trim stock is described in U.S. Patent Publication No. 2010- 0077842 Al.

"NOACK volatility" is determined using ASTM D5800 - 10, which is the Standard Test Method for Evaporation Loss of Lubricating Oils by the NOACK Method.

"Society of Automotive Engineers (SAE) J300" refers to the Engine Oil Viscosity

Classification most recently updated and published by SAE on April 2, 2013. The standard includes the following table:

SAE J300

(*) for OW-40, 5W-40 and 10W-40 grades (**) for 15W-40, 20W-40, 25W-40 and 40 grades

"Multigrade Engine Oil" refers to a lubricant meeting requirements of both a SAE viscosity grade in the upper portion of the SAE J300 table and an SAE viscosity grade in the lower portion of the SAE J300 table, as described previously. Two non-limiting examples of multigrade engine oils are SAE 15W-40 or SAE 15W-30.

"TBN booster" refers to an additive, or mixture of additives, that comprises a nitrogen- containing dispersant having a Total Base Number (TBN) from 45 to 145 mg KOH/g by ASTM D2896-1 1. In some embodiments, the nitrogen-containing dispersant may be ashless, for example a succinimide dispersant. The TBN booster can be designed primarily to provide additional basicity to the formulation (measured as Total Base Number [TBN], by ASTM D2896-1 1).

" ^■ Viscosity Modifier" refers to polymeric additives that provide lubricants with high and low temperature operabiiity. Viscosity modifiers are added to lubricants to change the lubricant's viscous response to temperature, and they improve the lubricant's viscosity index. Viscosity modifiers are also known as VI improvers and viscosity index improvers.

"Pour Point Depressant" refers to an additive that lowers the pour point of a. wax -containing lubricant by reducing the tendency of the wax to solidify.

"Oxidative Stability" refers to the resistance of a base oil or lubricant to react with oxygen, which can degrade the oil and contribute to varnish, deposits, and poor engine performance. Oxidative stability can be measured by a number of oxidation tests, including pressurized differential scanning calorimeter (PDSC), Caterpillar Micro-Oxidation test (CMOT), and Moderately High Temperature Thermo-Oxidation Engine Test (TEOST MHT).

"Shear Stability Index" (SSI) refers to a polymer's resistance to mechanical degradation (polymer coil breakage) under shearing stress in a European Diesel Injector Test by ASTM D6022-06 (R 2012) and ASTM D7109. The European Diesel Injector Test (ASTM D7109- 12) measures the permanent reduction in an oil's viscosity after 30 cycles through the test apparatus. For example, a SSI of 50 means that the additive will lose 50% of the viscosity it contributes to a lubricant.

"American Petroleum Institute (API) CJ-4 service category" refers to lubricants for use in high-speed four-stroke cycle diesel engines designed to meet 2010 model year on-highway and Tier 4 non-road exhaust emission standards as well as for previous model years. These lubricants are especially effective at sustaining emission control system durability where particulate filters and other advanced aftertreatment systems are used. API CJ-4 requirements were introduced in 2006 and are summarized below. The Standard Specification for Performance of Active API Service Category Engine Oils is ASTM D4485-1 lb. The associated ASTM test numbers are shown in parentheses in the summarized requirements, below.

API CJ-4 Performance Specification (Bench Tests)

Requirements Units Limits (1)

Chemical Limits (Non- Critical)

Sulfated Ash (D 874), max % 1.0

Phosphorus (D 4951), max % 0.12

Sulfur (D 4951), max % 0.4

NOACK Volatility

(D 5800)

Evap Loss @250°C, Vis % 13

Grades

other than 10W-30, max

Evap Loss @ 250°C, 10W-30,

max % 15 High Temp / High Shear

Viscosity (D 4683)

Viscosity @150°C, min

Shear Stability (D 7109)

KV @100°C after 90-passes for

XW-40, min

KV @100°C after 90-passes for

XW-30, min

Sooted Oil MRV (D 6896)

180 Hour Sample from

Mack T-1 1 or T-HA

Viscosity @-20°C, max cP 25,000 Yield Stress Pa <35

High Temp Corrosion,

135°C (D 6594)

Copper, used oil increase,

max ppm 20

Lead, used oil increase,

max ppm 120

Copper Strip Rating, max - 3

Seal Compatibility

(D 7216) (2)

Nitrile/NBR

Volume Change % +5/-3

Hardness Points +11-5

Tensile Strength % +10/-TMC1006

Elongation % +10/-TMC1006

Silicone/VMQ

Volume Change % +TMC1006/-3

Hardness Points +5/-TMC1006

Tensile Strength % +10/-45

Elongation % +20/-30

Polyacrylate/ACM

Volume Change % +5/-3

Hardness Points +8/-5

Tensile Strength % +18/-15

Elongation % +10/-35

Fluoroelastomer/FKM

Volume Change % +5/-2

Hardness Points +11-5

Tensile Strength % +10/-TMC1006

Elongation % +10/-TMC1006

Vamac G

Volume Change % +TMC1006/-3

Hardness Points +5/-TMC1006

Tensile Strength % +10/-TMC1006 Elongation % +10/-TMC1006

Foaming (D 892)

Foaming / Settling

Sequence I, max 10 / 0

Sequence II, max 20 / 0

Sequence III, max 10 / 0

API CJ-4 Performance Specification (Engine Tests)

Requirements Units Limits (1)

Test 2-Test 3-Test

Engine Oil Aeration

(D 6894)

Oil Aeration 8.0 8.0 8.0 Volume, max (MTAC) (MTAC) (MTAC)

Caterpillar IN (D 6750)

Top Land Heavy Carbon, max % 3 4 5

Top Groove Fill, max % 20 23 25

Weighted Demerits, max demerits 286.2 311.7 323.0 Average Oil Consumption (0-

252 hr), max g/kW-hr 0.5 0.5 0.5

Ring / Liner Scuffing None None None

Caterpillar C13 (D 7549)

Merits, min 1000 (3) 1000(3) 1000(3) Hot Stuck Rings None None None

Cummins ISB

(D 7484)

Tappet Wear, max mg 100 108 112

Cam Wear, max microns 55 59 61

Crosshead Weight Rate & Rate & Rate &

Loss mg Report Report Report

Cummins ISM (D 7468)

Merits, min 1000 (3) 1000(3) 1000(3)

Top Ring Wt Loss, max mg 100 100 100

Mack T-ll (D 7156)

Soot at 4cSt Inc, min % 3.5 3.4 3.3

Soot at 12cSt Inc, min % 6.0 5.9 5.9

Soot at 15cSt Inc, min % 6.7 6.6 6.5

Mack T-12 (D 7156)

Merits, min 1000 (3) 1000(3) 1000(3) Roller Follower Wear

Test (D 5966)

Roller Follower Pin microns 7.6 8.4 9.1 Wear, max (mils) (0.30) (0.33) (0.36)

Sequence IIIF

(D 6984) (4)

Viscosity Inc at 275 275 275

EOT, max % (MTAC) (MTAC) (MTAC)

(1) Limits approved at the ASTM HDEOCP meeting on January 26, 2006

(2) Limits expressed as +/- TMC1006 determined and adjusted through reference testing

(3) Requires all individual merit ratings to be equal to or greater than zero; see CJ-4 Merit System Summary

(4) Passing Seq IIIG viscosity increase at API SM limits is an acceptable alternate

Summary of API CJ-4 Merit Systems

Engine Tests Merit System Values

Max Anchor Cap Parameter

Merit (2) (3) Weight

(1)

Caterpillar C13

(D 7549)

TLC demerits 15 30 35 300

TGC demerits 30 46 53 300

2RTC demerits 5 22 33 100

Oil Consumption

Increase g/hr 10 25 31 300

Cummins ISM

(D 7468)

Crosshead Weight

Loss mg 4.3 5.7 7.1 350

Injector Screw Wear mg 16 27 49 350

Oil Filter Pressure

Delta kPa 7 13 19 150

Sludge merits 9.3 9.0 8.7 150

Mack T-12 (D 7156)

Top Ring Weight Loss mg 35 70 105 200

Cylinder Liner Wear microns 12 20 24 250

Lead Increase 0-300

hrs ppm 10 25 35 200

Lead Increase 250-300

hrs ppm 0 10 15 200

Phase 2 Oil g/hr 50 65 85 150 Consumption

(1) Results at the Max Merit point; merits are equal to twice the Parameter Weight; no additional merits awarded for

performance better than the Max Merit level

(2) Results at the Anchor receive merits equal to the Parameter Weight

(3) Results at the Cap receive zero merits; performance worse than the Cap receives negative merits and the overall test result is a fail regardless of the total merit rating

DETAILED DESCRIPTION

The lubricating oil composition comprises a combination of at least two Group II base oils and additives that are selected to meet heavy duty engine oil specifications, including API-CJ-4.

Base Oils

Each Group II base oil in the lubricating oil composition has a different kinematic viscosity at 100°C. A first Group II base oil has a first kinematic viscosity at 100°C from 5,0 to 8,0 mm ² /s. In one embodiment the first kinematic viscosity at 100°C is from 6.2 to 7.0, such as from 6.3 to 6.9 mrn ² /s. A second Group II base oil has a second kinematic viscosity from 10 to 14 mm7s, such as from 1 1 to 13, or from 1 1 ,7 to 12.7 mm ² /s. In one embodiment, at least one or all of the Group II base oils have viscosity indexes less than 110, such as from 90 to 109, or from 95 to 109. In one embodiment the first Group II base oil has a first viscosity index less than 110 and the second Group II base oil has a second viscosity index less than 110.

When making the lubricating oil composition, at least two Group II base oils are blended together to make a blended base oil mixture having a blended base oil viscosity from 6.0 to 7.3 mra7s. In one embodiment, the blended base oil mixture has a blended base oil viscosity from 6.50 to 6.80 mm7s. In one embodiment, no trim stock is blended into the blended base oil mixture or added to the blended base oil mixture, as trim stock is not needed to bring the lubricating oil composition to the SAE 15W-30 viscosity grade. In another embodiment, a trim stock can be added to the blended base oil mixture.

Detergent Inhibitor Additive Package The lubricating oil composition also comprises a detergent inhibitor additive package designed to meet a CJ-4 service category. In one embodiment, the detergent inhibitor additive package is one designed to meet the CJ-4 service category in a multigrade engine oil blended with one or more Group II base oils. Different detergent inhibitor additive packages are needed in Group II base oils because of their typically lower oxidative stability compared to more highly refined Group III or synthetic Group IV base oils. In one embodiment, the multigrade engine oil that the detergent inhibitor additive package is designed for is a SAE 15W-40.

In one embodiment, the amount of the detergent inhibitor additive package in the lubricating oil composition can be from 12 to 20 wt%, such as from 13 to 19 wt%, or from 14 to l7 wt%.

In one embodiment, the detergent inhibitor additive package comprises at least one detergent, at least one dispersant, at least one antiwear agent, at least one antioxidant, and other additives.

The detergent inhibitor additive package typically comprises at least one metal- containing detergent. The detergent can function as one or more of a) a detergent to reduce or remove deposits, b) as an acid neutralizer, or c) as a rust inhibitor. The metal-containing detergent can comprise a polar head with a long hydrophobic tail, with the polar head comprising a metal salt of an acid organic compound. In one embodiment the metal- containing detergent is overbased. Overbased metal-containing detergents can be single phase, homogeneous Newtonian systems characterized by a metal content in excess of that which would be present according to the stoichiometry of the metal and the particular acidic organic compound reacted with the metal to prepare the detergent. An overbased metal- containing detergent can be made by reacting an acidic material (typically an inorganic acid or lower carboxylic acid) with a mixture comprising an acidic organic compound in a reaction medium comprising at least one inert, organic solvent in the presence of a stoichiometric excess of a metal base and a promoter. Examples of acidic materials used to make metal-containing detergents are carboxylic acids, sulfonic acids, phosphorus-containing acids, phenols, and mixtures thereof. Mixtures of different metal-containing detergents can be present in the detergent inhibitor additive package. The detergent inhibitor additive package typically comprises dispersants that can be used to maintain in suspension insoluble materials resulting from oxidation during use. The dispersants can be ashless. Nitrogen-containing ashless dispersants are basic, and contribute to the TBN of the lubricating oil composition. Representative ashless dispersants include, but are not limited to, amines, alcohols, amides, or ester polar moieties attached to a polymer backbone via bridging groups. Ashless dispersants can be selected, for example, from soluble salts, esters, amino-esters, amides, imides, and oxazolines of long chain hydrocarbon substituted mono and dicarboxylic acids or their anhydrides; thiocarboxylate derivatives of long chain hydrocarbons, long chain aliphatic hydrocarbons having polyamine attached directly thereto; and Mannich condensation products formed by condensing a long chain substituted phenol with formaldehyde and polyalkylene polyamine. Carboxylic dispersants are reaction products of carboxylic acylating agents with nitrogen containing compounds, organic hydroxyl compounds, or aromatic compounds. Succinimide dispersants are a type of carboxylic dispersant. Examples of succinimide dispersants include those described, for example, U.S. Pat. Nos. 3, 172892, 4,234,435, and 6, 165,235. In one embodiment, the detergent inhibitor additive package comprises more than one dispersant, such as a blend of at least at least two of the following: a succinimide dispersant, a Mannich dispersant, an ester-containing dispersant, a condensation product of a fatty hydrocarbyl monocarboxylic acylating agent with an amine or ammonia, an alkyl amino phenol dispersant, a hydrocarbyl-amine dispersant, a polyether dispersant, a polyetheramine dispersant, a viscosity modifier containing dispersant functionality (for example polymeric viscosity index modifiers (VMs) containing dispersant functionality). In one embodiment, the detergent inhibitor additive package comprises at least one ethylene carbonate- treated bis-succinimide dispersant and at least one borated bis-succinimide dispersant, such as those described in US20030224948A1 . Examples of detergent inhibitor additive packages with more than one dispersant are described in U.S. Patent Nos. 7,902, 130; 8,183, 187; and 8,598,099; and in WO2010075103A2.

The detergent inhibitor additive package can comprise antioxidant compounds. These oxidation inhibitors can include, for example, hindered phenols, ashless oil soluble phenates and sulfurized phenates, alkyl-substituted diphenylamine, alkyl-substituted phenyl, naphthylamines and the like, and mixtures thereof. The detergent inhibitor additive package can comprise anti-wear agents, such as molybdenum-containing complexes and metal dihydrocarbyl dithiophosphate. As their name implies, anti-wear agents reduce wear of moving metallic parts. Examples of anti-wear agents include, but are not limited to, phosphates, carbamates, esters, molybdenum complexes, and mixtures thereof. In one embodiment, the detergent inhibitor additive package can comprise a molybdenum/nitrogen-containing complex. In one embodiment, the detergent inhibitor additive package can comprise a zinc dialkylthiophosphate.

The detergent inhibitor additive package can comprise one or more other additives that impart auxiliary functions to help meet performance specifications. These other additives can include, for example, friction modifiers, rust inhibitors, dehazing agents, demulsifying agents, metal deactivating agents, pour point depressants, viscosity modifiers, antifoaming agents, co-solvents, package compatibilisers, corrosion-inhibitors, dyes, extreme pressure agents, multifunctional additives, and mixtures thereof.

Examples of friction modifiers include fatty alcohol, fatty acid, amine, borated ester, other esters, phosphates, phosphites, phosphonates, molybdenum compounds, and mixtures thereof. Examples of molybdenum compounds that can be used as friction modifiers include organo molybdenum compounds, molybdenum dialkyldithiocarbamates, molybdenum dialkylthiophosphates, molybdenum disulphide, trimolybdenum cluster

dialkyldithiocarbamates, non-sulphur molybdenum compounds and mixtures thereof.

Examples of rust inhibitors include one or more of the following: nonionic polyoxy ethylene surface active agents: poly oxy ethylene lauryl ether, poly oxy ethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol mono-oleate, and polyethylene glycol mono-oleate. Other compounds that can function as rust inhibitors are stearic acid and other fatty acids, dicarboxylic acids, metal soaps, fatty acid amine salts, metal salts of heavy sulfonic acid, partial carboxylic acid ester of polyhydric alcohol, and phosphoric ester.

Examples of demulsifying agents include the addition product of alkylphenol and ethylene oxide, polyoxyethylene alkyl ether, polyoxyethylene sorbitan ester, and

combinations thereof. Examples of pour point depressants are polymethacrylates, polyalkylmethacrylates, polyacrylates, di(tetra paraffin phenol) phthalate, condensation products of tetra paraffin phenol, and condensation product of a chlorinated paraffin wax with naphthalene. Examples of viscosity modifiers include polymethacrylate-type polymers, ethylene-propylene copolymers, styrene-isoprene copolymers, hydrated styrene-isoprene copolymers, polyisobutylene, dispersant type viscosity modifiers, and mixtures thereof.

Examples of antifoaming agents are alkyl methacrylate polymers and dimethyl silicone polymers.

Examples of extreme pressure agents include zinc dialky- 1 -dithiophosphate (primary alkyl, secondary alkyl, and aryl type), diphenyl sulfide, methyltrichlorostearate, chlorinated naphthalene, fluoroalkylpolysiloxane, lead naphthenate, neutralized phosphates,

dithiophosphates, sulfur-free phosphates, and combinations thereof.

Examples of metal deactivating agents include disalicylidene propylenediamine, triazole derivatives, mercaptobenzothiazoles, mercaptobenzimidazoles, and combinations thereof . Examples of multifunctional additives include sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum organo phosphorodithioate, oxymolybdenum monoglyceride, oxymolybdenum diethylate amide, amine-molybdenum complex compound, and sulfur-containing molybdenum complex compound.

The detergent inhibitor additive package is added to the blended base oil mixture, along with 0.50 to 4.95 wt% of a viscosity modifier.

Viscosity Modifier

The lubricating oil composition comprises 0.5 to 4,95 wt% viscosity modifier, on an as received basis in a carrier oil. Irs other embodiments, the lubricating oil composition comprises 0.50 to 4.00 wt% or 0,75 to 3.5 wt% of the viscosity modifier. In one

embodiment, the lubricating oil composition comprises 1.50 to 2.50 wt% of the viscosity modifier. Viscosity modifiers are usually supplied diluted in a carrier oil and they constitute about 5 to 50 wt% active ingredient. The viscosity modifier imparts higher viscosity at elevated temperatures, and acceptable viscosity at low temperatures. Suitable viscosity modifiers are polymers and include high molecular weight (polymeric) hydrocarbons, polyesters and viscosity index improver dispersants that function as both a viscosity index improver and a dispersant.

Typical molecular weights of these viscosity modifiers are from 10,000 to 1,000,000, such as from 20,000 to 500,000, or from 50,000 to 200,000.

Examples of viscosity modifiers are polymers and copolymers of methacrylate, butadiene, olefins, or alkylated styrenes. Poiyisobutylene is a specific example. Another suitable viscosity modifier is polymethacrylate (copolymers of various chain length alkyl methacrylates, for example). Other suitable viscosity modifiers include copolymers of ethylene and propylene, hydrogenated block copolymers of styrene and isoprene, hydrated styreneisoprene copolymers, polybutene, polyisobudylene, vinylpyrrolidone and methacrylate copolymers, and polyacrylates (copolymers of various chain length acrylates, for example). In one embodiment the viscosity modifier is an olefin copolymer or a hydrogenated styreneisoprene copolymer of 50,000 to 200,000 molecular weight. In one embodiment, the viscosity modifier is a non-dispersant olefin copolymer. In one embodiment, the viscosity- modifier is a shear stable polymer, such as a shear stable non-dispersant olefin copolymer. In the context of this disclosure a shear stable viscosity modifier has a shear stability index (SSI) of 10-40.

In one embodiment, the viscosity modifier contains: a) an amino alcohol reaction product prepared by isomerizing a normal alpha olefin to form an internal olefin; epoxidizing said olefin; and reacting with a mono-hydroxyl hydroearbyl amine; and b) an ester of glycerol and a carboxylic acid containing 0 to 3 double bonds. These friction modifiers are described in U.S. Pat. No. 8,703,680.

TBN Booster The lubricating oil composition can also comprise a TBN booster that raises the TBN of the lubricating oil composition. In one embodiment, the TBN booster raises the TBN of the lubricating oil composition to from 8.55 to 1 1.00 mg KOH/g by ASTM D2896-11. As indicated previously, the TBN booster can be designed primarily to provide additional basicity to the formulation (measured as total base number (TBN), by ASTM D2896-1 1). The additional basicity provided by a TBN booster can be used to distinguish between different formulations of lubricating oil compositions and can also provide additional corrosion protection, since corrosion is less likely to occur in a moderately alkaline environment. Acids can be generated from fuel combustion or from oxidation of engine oil in hot spots, and the additional basicity can neutralize these acids. If the TBN of the engine oil is too high, the engine oil can also become aggressive to metal surfaces and appear as wear in engine tests.

Examples of TBN boosters are described in US20130281336A1, US20120040876A1, WO2014033634A2, JP2013072088A, US8703682B2, US201 10105374A1, US7749948B2, and EP708171B1. In one embodiment, the lubricating oil composition comprises 0.50 to 3.50 wt% of the TBN booster, such as (for example) 0.75 to 2.25 wt% of the TBN booster.

In one embodiment, the TBN booster comprises at least 60 wt% dispersants, at least an antioxidant, and less than 5 wt% overbased metal detergent. In another embodiment, the TBN booster comprises at least two dispersants, at least an anti-oxidant, and at least a detergent.

Examples of dispersants that can be used in the TBN booster include one or more of borated dispersants and non-borated dispersants. In one embodiment, the dispersants used in the TBN booster are ashless. Examples of ashless dispersants are alkenyl succinimides and succinimides. These dispersants can be further modified by reaction with, for example, with boron or ethylene carbonate. Ester-based ashless dispersants derived from long chain hydrocarbon-substituted carboxylic acids and hydroxy compounds may also be employed. Other ashless dispersants are those derived from polyisobutenyl succinic anhydride.

In one embodiment, the dispersant used in the TBN booster is a non-conventional polysuccinimide dispersant derived from terpolymer PIBSA, N-phenylenediamine and a polyether amine. Dispersants of this type are described in U.S. Pat. No. 7,745,541.

Examples of antioxidants that can be used in the TBN booster include one or more of esters of thiodicarboxylic acids, di-thiocarbamates, such as 15-methylenebis (di-butyl di- thiocarbamate), salts of di-thiophosphoric acids, alkyl or aryl phosphates. Molybdenum compounds, such as amine-molybdenum complex compound and molybdenum di- thiocarbamates may also be used as anti-oxidants and hindered phenols, such as 4,4'- methylene-bis(2,6-di-tert-butylphenol), 4,4'-bis(2,6-di-tert-butylphenol), 4,4'-bis(2-methyl - 6 -tert-butylphenol), 2,2'-methylene-bis(4-methyl-6- tert-butylphenol), 4,4'-butylidene-bis (3-methyl- 6-tertbutylphenol), 4,4'-isopropylidene-bis(2,6-di-tertbutylphenol), 2,2'- methylene-bis (4 -methyl- 6-nonylphenol), 2,2'-isobutylidene-bis (4,6 -dimethylphenol), 2,2'- 5-methylene-his (4 -methyl- 6 -cyclohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di- tert-butyl4-ethylphenol, 2,4-dimethyl-6-tert-butyl-phenol, 2,6-di-tert-l-dimethylamino-p- cresol, 2,6 -di-tert-4 -(N,N'-di-methylaminomethylphenol),4,4'-thio -bis (2 -methyl-6 -tert- butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3-methyl-4-hydroxy-5-tert- 10- butylbenzyl)-sulfide, and bis(3,5-di-tert-butyl-4-hydroxybenzyl). In one embodiment the TBN booster comprises hindered phenols that do not contribute to the phosphorus, sulfur and sulfated ash content of the engine oil. In one embodiment, the TBN booster comprises 15 to 30 wt% of a diphenyl amine antioxidant. In one embodiment, the TBN booster comprises 20 to 40 wt% of an ashless non- borated dispersant. In one embodiment, the TBN booster comprises 35 to 50 wt% of a borated dispersant. In one embodiment, the TBN booster comprises 0.5 to 3 wt% of a magnesium sulfonate detergent. For example, the TBN booster can comprise 15 to 30 wt% of a diphenyl amine antioxidant, 20 to 40 wt% of an ashless non-borated dispersant, 35 to 50 wt% of an ashless borated dispersant, and 0.5 to 3 wt% of a magnesium sulfonate detergent.

Examples of diphenyl amine antioxidants that may be included in the TBN booster include monoalkylated diphenylamine, dialkylated diphenylamine, trialkylated

diphenylamine, and mixtures thereof. Some of these include butyldiphenylamine, di- butyldiphenylamine, oxtyldiphenylamine, di-octyldiphenylamine, nonyldiphenylamine, di- nonyldiphenylamine, t-butyl-t-octyldiphenylamine, and mixtures thereof.

Examples of overbased metal detergents that can be included in the TBN booster are low and high overbased sulfonic acids or phenols or Mannich condensation products of alkylphenols, aldehydes and amines. In one embodiment, the overbased metal detergent in the TBN booster does not include overbased salicylic acids or carboxylic acids. In one embodiment the overbased metal detergent that can be included in the TBN booster is a highly overbased magnesium sulfonate detergent having a TBN of about 300 or greater, such as about 350 to 500. For example, the highly overbased magnesium sulfonate detergent can be a highly overbased magnesium alkyltoluene sulfonate, such as described in U.S. Patent Pub. No. 2011013671 1 Al . Oilier Additives

A small amount of pour point depressant can also be blended into the lubricating oil composition. When used, the amount of pour point depressant included in the lubricating oil composition can be 0.01 to 2.00 wt%. Examples of pour point depressants are

polymethacrylates, polyalkylmefhacryla es, polyacrylaies, diftetra paraffin phenol) phthalate, condensation products of tetra paraffin phenol, and condensation product of a chlorinated paraffin wax with naphthalene. These pour point depressants, and other suitable additives that can be included in the lubricating oil composition, are described in Chemistry and Technology of Lubricants (Google eBook), R. M. Mortier, Malcolm F. Fox, S. T. Orszulik, Springer, Apr 14, 201 1. Other suitable additives that can be blended into the lubricating oil composition can include friction modifiers, rust inhibitors, dehazing agents, demulsifying agents, metal deactivating agents, antifoaming agents, co-solvents, package compatibilisers, corrosion- inhibitors, dyes, extreme pressure agents, and mixtures thereof.

In one embodiment, the step of adding the detergent inhibitor additive package, the TBN booster (when used), and the viscosity modifier to the blended base oil mixture is done such that the resulting lubricating oil composition comprises 70 to 85 wt% of the first Group II base oil and from 2.0 to 6.5 wt% of the second Group II base oil.

In one embodiment, the step of adding the detergent inhibitor additive package, the TBN booster (when used), and the viscosity modifier to the blended base oil mixture is done such that the resulting lubricating oil composition has a sulfated ash from 0.50 to 1.10 wt.%, such as from 0,60 to 1.05 wt%. In another embodiment, the step of adding the detergent inhibitor additive package, the TBN booster (when used), and the viscosity modifier to the blended base oil mixture is done such that the resulting lubricating oil composition has a sulfated ash of 1.0 or less, such as 0.65 to 1.00 wt% In one embodiment, the step of adding the TBN booster to the blended base oil mixture is done such that the lubricating oil composition comprises 0.75 to 2.25 wt% of the TBN booster. In one embodiment, the step of adding the viscosity modifier to the blended base oil mixture is done such that the lubricating oil composition comprises 0.75 to 3.5 wt% of the viscosity modifier.

Lubricating Oil Composition Performance

In one embodiment the SAE 15W-30 lubricating oil composition of the present invention meets API CJ-4. Other industry specifications that the SAE 15 W-30 lubricating oil composition can meet include API SM, Cummins CES 20081, Daimler MB 228.31, Volvo VDS-4, Mack Trucks (Volvo) EO-0 Premium Plus 2007, Renault Tracks (Volvo) RLD-3, Caterpillar ECF-3, Detroit Diesel Power Guard 93K218, Deutz DQC HI- 10 LA, MAM Track & Bus M3575. The SAE 15 W-30 lubricating oil composition of the present invention has excellent oxidative stability as demonstrated in the Caterpillar Micro-Oxidation Test (CMOT). CMOT is a test used to measure the thermal and oxidative stability of fully formulated diesel engine oils under thin film conditions. This test provides an indication as to whether a candidate oil is worthy of field trial in a Caterpillar 3600 series engine. The results generated in the CMOT give an Induction Time in minutes indicating relative time for antioxidants in the oil to deplete. The development of the Caterpillar Micro -Oxidation Test (CMOT) is discussed in #890239 of the SAE Technical Paper Series "Evaluation of Diesel Engine Lubricants by Micro-Oxidation," authored by Fulvio N. Zerla and Robert A. Moore. The induction time to deposit formation in the CMOT can be determined by calculating the intercept between a baseline formed where minimal deposits are seen, and the slope formed where a rapid rise in deposit formation is seen. Longer induction times correspond to improved deposit control. An Induction Time of 70 minutes or greater is generally considered acceptable for some heavy duty engine oils. In its publication SEBU7003-4 "Caterpillar 3600 Series and C 280 Series Diesel Engines Fluids Recommendation", Caterpillar specifies that engine oil must demonstrate a minimum Induction Time of 90 minutes in the CMOT. The SAE 15W-30 lubricating oil composition provides an Induction Time in the CMOT from 270 to 450 minutes, such as from 330 to 400 minutes, or 350 to 400 minutes. In one embodiment, the SAE 15W-30 lubricating oil composition also provides less than 20 mg total deposits, such as only 5 to 16 mg total deposits, in a Moderately High Temperature (MHT) Thermo-Oxidation Engine Test by ASTM D7097-09. The SAE 15W-30 lubricating oil composition additionally can provide excellent engine wear protection. In one embodiment, the SAE 15W-30 lubricating oil composition provides an average cam lobe wear in the Cummins ISB test less than 49 μηι, such as from 15 to 48 μηι or from 20 to 45 μηι. In one embodiment, the SAE 15W-30 lubricating oil composition provides an average cam and lifter wear in a Sequence DIG test less than 22 μηι, such as from 5 to 20 μηι. In one embodiment, the SAE 15W-30 lubricating oil composition provides a cam wear average in a Sequence IVA test less than 1 1 μηι, such as from 1 to 10 μπι.

In one embodiment, the SAE 15W-30 lubricating oil provides superior shear stability. In one embodiment, the SAE 15W-30 lubricating oil composition provides a percent v scosity loss of the 30-cycle sheared oil (PVL30) of less than 0.80%, such as from 0.20 to 0.60%. In one embodiment, the SAE 15W-30 lubricating oil composition provides a percent viscosity loss of the 90-cyele sheared oil (PVL90) of less than 1.00%, such as from 0.20 to 0.80%. In one embodiment, the SAE 15W-30 lubricating oil composition provides a percent change in viscosity at 100°C in the KRL Shear Stability Test, performed according to CEC- L-45-99, less than 20%, such as from 6 to 16%.

EXAMPLES

Example 1: Lubricating Oil Compositions

Three different lubricating oil compositions with different viscosity grades were blended as described in Table 1. These lubricating oil compositions were formulated to meet heavy duty engine oil specifications and major diesel engine manufacturers' requirements.

Base oil blends were mixed to meet defined base oil blend viscosities and then engine oil additives were mixed into the base oil blends in proportions needed to give a sulfated ash of 0.65 to 1.00 wt%, a TBN from 7.5 to 9.5 mg KOH/g, a High- Temperature High-Shear (HTHS) from 3.5 to 4.0 mPa-s, and a kinematic viscosity at 100°C within the defined viscosity grades of SAE 10W-30, SAE 15W-30, or SAE

15W-40. Less than 7 wt% of a trim stock, Chevron 1 10RLV, was used to bring the blend oil viscosity into the desired range for the SAE 10W-30 lubricating oil

composition. No trim stock was used in formulating the SAE 15W-30 or SAE 15W-40 lubricating oil compositions. Table

Components, SAE 10W-30 SAE 15W-30 SAE 15W-40 wt%

Chevron Example Chevron

Ursa® Super Lubricating Oil Ursa® Super

Plus EC 10W- Composition Plus EC 15W-

30 40

Chevron 220R 33.69 77.12 69.98

Chevron 600R 7.84 4.22 8.62

Chevron 5.66 0 0

110RLV

Estimated Base 5.66 6.65 6.89

Oil Blend

Viscosity,

mm ² /s

DI Additive 16.9 14.69 + 1 TBN 14.69

Package, wt% booster

Viscosity 4.35 2.0 6.31

Modifier, wt%

Pour Point 0.40 0.40 0.40

Depressant,

wt%

Ursa®, OLOA®, and PARATONE® are registered trademarks owned by Chevron Intellectual Property L.L.C.

Chevron 220R , Chevron 600R, and Chevron 1 lORLV are API Group II base oils from Chevron Corporation. Chevron 220R and Chevron 600R had viscosity indexes from 102 to 109. Chevron 110RLV had a viscosity index from 110 to 119. The Detergent Inhibitor (DI) Additive Packages used were either used alone or with the addition of a TBN booster. The TBN booster had a TBN from 50 to 62 mg KOH/g by ASTM D2896-11. The TBN booster contributed the following to the lubricating oil composition: 0.5 wt% non-borated dispersant as described in U.S. Pat. No. 7,745,541, 0.394 wt% diphenyl amine antioxidant, 0.75 wt% borated succinimide dispersant, 0.03 wt% heavy overbased magnesium sulfonate detergent, and 0.07 wt% diluent oil. The TBN booster, when used, was used in an amount to raise the TBN by about 1.0 base number by ASTM D2896-11, but it did not increase the sulfated ash above 1.00 in the lubricating oil composition. In this example the total amount of the TBN booster used was 1.744 wt%

The Detergent Inhibitor (DI) Additive Packages used in the base oil blends of this example were heavy duty diesel engine oil additives designed to meet or exceed the API Service Category CJ-4 in the SAE 15W-40 viscosity grade when blended with Group II base oils. The Viscosity Modifiers that were used were Lubrizol® 7075F or PARATONE® 801 1, which are shear stable non-dispersant olefin copolymer viscosity modifiers.

The pour point depressant that was used was a polyalkylmethacrylate (PAMA), Viscoplex™ 1 -604, a trademarked pour point depressant from Degussa of Germany.

Key properties of these three different blends are summarized in Table 2.

Table 2

Example 2: Performance Tests for Oxidation Stability

The lubricating oil compositions described in Example 1 were tested in a number of oxidation tests as shown in Table 3. Where more than one result is shown, these are replicated tests.

Table 3

SAE SAE SAE

Oxidation Test Method 10W-30 15W-30 15W-40

Test, minutes

Moderately ASTM 40.2, 37.7 10, 11.2 19.4, 19.1 High D7097-09

Temperature

Thermo- Oxidation

Engine Test

(TEOST

MHT), mg

total deposit

TEOST and MHT are registered trademarks of the Tannas Co. The European

Automobile Manufacturers' Association (ACEA) represents the 15 Europe-based car, van, truck and bus makers: BMW Group, Daimler, DAF, Fiat, Ford of Europe, General Motors Europe, Hyundai Motor Europe, Iveco, Jaguar Land Rover, PSA Peugeot Citroen, Renault, Toyota Motor Europe, Volkswagen Group, Volvo Cars, Volvo Group.The Coordinating European Council's CEC L-85-T-99 pressurized differential scanning calorimeter (PDSC) test was developed in Europe for the ACEA specifications for heavy duty diesel oils. This test differentiates between base oils and additives, and indicates synergies between antioxidants. The PDSC results can correlate with other oxidation tests.

Notably, this 15W-30 lubricating oil composition has met all the requirements for API

CJ-4, API SM, Cummins CES 20081, Volvo VDS-4, Mack Trucks (Volvo) EO-0 Premium Plus 2007, Renault Trucks (Volvo) RLD-3, and Caterpillar ECF-3. The oxidative stability of this SAE 15W-30 lubricating oil composition was outstanding.

Example 3; Shear Stability Tests

The lubricating oil compositions described in Example 1 were tested in two different shear stability tests. The percent viscosity losses obtained in these tests are shown in Table 4.

Table 4

The KRL shear stability test was performed in a taper roller bearing rig, according to the CEC-L-45-99 test method that published May 28, 2014. All three lubricating oil compositions provided acceptable shear stability performance, but the SAE 15W-30 lubricating oil composition provided improved results in both shear stability tests.

Example 4: Performance Tests for Engine Wear

The lubricating oil compositions described in Example 1 were tested in three different engine tests, as shown in Table 4.

Table 5

All three lubricating oil compositions provided acceptable engine performance, but the SAE 15W-30 lubricating oil composition provided improved wear results in the Cummins ISB and Sequence IVA engine tests.

The transitional term "comprising", which is synonymous with "including," "containing," or

"characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. The transitional phrase "consisting of excludes any element, step, or ingredient not specified in the claim. The transitional phrase "consisting essentially of limits the scope of a claim to the specified materials or steps "and those that do not materially affect the basic and novel characteristic(s)" of the claimed invention.

For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term "about." Furthermore, all ranges disclosed herein are inclusive of the endpoints and are independently combinable. Whenever a numerical range with a lower limit and an upper limit are disclosed, any number falling within the range is also specifically disclosed. Unless otherwise specified, all percentages are in weight percent.

Any term, abbreviation or shorthand not defined is understood to have the ordinary meaning used by a person skilled in the art at the time the application is filed. The singular forms "a," "an," and "the," include plural references unless expressly and unequivocally limited to one instance.

All of the publications, patents and patent applications cited in this application are herein incorporated by reference in their entirety to the same extent as if the disclosure of each individual publication, patent application or patent was specifically and individually indicated to be incorporated by reference in its entirety.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. Many modifications of the exemplary embodiments of the invention disclosed above will readily occur to those skilled in the art. Accordingly, the invention is to be construed as including all structure and methods that fall within the scope of the appended claims. Unless otherwise specified, the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub- generic combinations of the listed components and mixtures thereof.

The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.