EP0994174A1

What Is The Makeup Of Atf

Info

Publication number: EP0994174A1
Application number: EP99307410A
Authority: EP
Inventors: David C. Kramer; Jaime Lopez; Jay Thousand. Peterson; Marker 50. Sztenderowicz; John A. Zakarian; Russel R. Krug; Stephen M. Lee; Joseph Yard. Pudlak
Original assignee: Chevron USA Inc
Current assignee: Chevron USA Inc
Priority date: 1998-10-15
Filing date: 1999-09-20
Publication date: 2000-04-19
Also published as: US6110879A

Abstract

The nowadays invention provides for a lubricating composition including: a hydrocracker-derived, highly naphthenic, low viscosity alphabetize mineral oil; from almost 2 wt. % to almost 14 wt. % of at least one polymethacrylate polymer; and from about 2 wt. % to about 14 wt. % of a operation condiment parcel. The hydrocracker-derived, highly naphthenic, depression viscosity alphabetize mineral oil is prepared by: (1) passing a first bottoms portion including not more than almost 67 wt. % of a fuels hydrocracker bottoms recycle stream to a dewaxing zone; and (ii) passing a second bottoms portion including at least about 33 wt. % of the recycle stream back to the fuels hydrocracker for additional processing; and where the recycle stream has a viscosity at 100°C of less than about iv.0; (3) contacting the showtime bottoms portion with a dewaxing catalyst nether catalytic dewaxing conditions, where at least a portion of the hydrocracker bottoms is substantially dewaxed; and (4) contacting at least a portion of the essentially dewaxed hydrocracker bottoms with a hydrofinishing goad nether hydrofinishing conditions, thereby producing a hydrofinished, dewaxed hydrocracker bottoms; and removing from the hydrofinished, dewaxed hydrocracker bottoms at least i light fraction including diesel or jet fuel range material, thereby leaving a heavy fraction including the hydrocracker-derived, highly naphthenic, viscosity index mineral oil having a naphthenes content of at least nearly 33 wt. %. The lubricating limerick has an unsheared kinematic viscosity at 100°C of at least nearly vii.3 centistokes; a sheared kinematic viscosity at 100°C of at least about 6.8 centistokes, where shear is measured by the twenty-hour KRL method; and a Brookfield viscosity at -40°C of no greater than about 10,000 centipoise.

Description

I. FIELD OF THE INVENTION

The present invention relates to a lubricating limerick. More specifically, the invention relates to an automatic manual fluid composition having high performance at low and high temperatures.

II. BACKGROUND OF THE INVENTION

Automatic transmission fluids are lubricants used in motor vehicle transmissions. Different types of automatic transmission fluids are used depending on the design and severity of application. Generally, automated transmission fluids are designed to come across specific manufacturer requirements.
An automated transmission is equanimous of a complex variety of mechanical parts which operate at close tolerances. The purpose of automatic transmission fluid is to lubricate these close-fitting parts to reduce wearable and keep down temperature due to friction. To perform this function, the automatic transmission fluid must maintain its viscosity within certain specifications. Achieving this function is complicated by the changing temperatures under which the manual is operated. It is desirable that an automatic transmission fluid perform well in all the various temperature conditions nether which the manual will operate.
For example, in a Northern location, the automatic transmission fluid may be below 32°F prior to utilize and then heat upward to over 300°F during utilize. Mineral oil based lubricating oils typically have higher viscosities at lower temperatures and lower viscosities at college temperatures. Equally automatic transmissions evolve, however, the maximum viscosity at depression temperatures is reduced since too glutinous an automatic transmission fluid will not adequately flow equally needed to actuate the hydraulic valves and other hydraulic mechanisms of the automatic transmission. Automobile manufacturers accept recently changed their specifications for automatic manual fluid to crave lower maximum viscosities at low temperatures. The next generation automatic transmissions will require next generation automatic transmission fluids, peculiarly to be sure the automatic transmission fluid flows fairly at low temperatures. For example, new generation automatic transmission fluids must take Brookfield viscosities at -forty°C of less than 10,000 cP, 13,000 cP, or 17,500 cP. Current requirements for automated transmission fluids typically merely crave a Brookfield viscosity at -forty°C of less than xx,000 cP.
Synthetic lubricants made from polyalphaolefins ("PAO's") and some new unconventional high viscosity index mineral base oils tin be used to meet these new viscometric requirements. Nonetheless, those are expensive to manufacture. It would be advantageous to have a relatively inexpensive mineral oil-based lubricant that can lower the cost of meeting the new viscometric requirements. The lubricating composition of the nowadays invention meets this need.

III. SUMMARY OF THE INVENTION

The present invention provides for a lubricating composition including: (i) a major corporeality of a base oil mixture including: from about 0 wt. % to virtually 90 wt. % of a kickoff mineral oil selected from a high viscosity index mineral oil, a conventional low viscosity index mineral oil, and mixtures thereof; and from about x wt. % to virtually 100 wt. % of a 2d mineral oil including a hydrocracker-derived, highly naphthenic, low viscosity index mineral oil; from about 2 wt. % to about 14 wt. % of at least i polymethacrylate polymer; and from about 2 wt. % to most 14 wt. % of a functioning additive package.
The hydrocracker-derived, highly naphthenic, low viscosity index mineral oil is prepared by: (1) passing a first bottoms portion including not more than near 67 wt. % of a fuels hydrocracker bottoms stream to a dewaxing zone; and (two) passing a second bottoms portion including at least most 33 wt. % of the bottoms stream back to the fuels hydrocracker for additional processing; and where the bottoms stream has a viscosity at 100°C of less than about four.0 cSt; (iii) contacting the first bottoms portion with a dewaxing catalyst under catalytic dewaxing conditions, where at to the lowest degree a portion of the hydrocracker bottoms is substantially dewaxed; (4) contacting at to the lowest degree a portion of the substantially dewaxed hydrocracker bottoms with a hydrofinishing catalyst under hydrofinishing conditions, thereby producing a hydrofinished, dewaxed hydrocracker bottoms; and removing from the hydrofinished, dewaxed hydrocracker bottoms at least one light fraction including diesel or jet fuel range textile, thereby leaving a heavy fraction including the hydrocracker-derived, highly naphthenic, viscosity index mineral oil having a naphthenes content of at least nigh 33 wt. %.
The lubricating composition has an unsheared kinematic viscosity at 100°C of at least about 7.3 centistokes; a sheared kinematic viscosity at 100°C of at least about six.8 centistokes, where shear is measured past the xx-60 minutes KRL method; and a Brookfield viscosity at -40°C of no greater than almost x,000 centipoise.

IV. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A. Viscometric Performance Specifications

The automated manual fluid compositions of the invention preferably meet one or more of the viscometric property sets given in Tables i-4 below. These viscometric performance specifications are from actual specifications, or composites thereof, of automobile manufacturers for the adjacent generation automatic manual fluids.

Holding	Target Value	Method of Measurement
Unsheared Kinematic Viscosity at 100°C	≥7.3 cSt.	ASTM D-445
Sheared Kinematic Viscosity at 100°C	≥6.8 cSt.	Shear: CEC L-45-T-93. (20 hr. KRL Method) Vis: ASTM D-445
Brookfield Viscosity at -40°C	≤ten,000 centipoise	ASTM D-2983

Holding	Target Value	Method of Measurement
Unsheared Kinematic Viscosity at 100°C	≥6.5 cSt.	ASTM D-445
Sheared Kinematic Viscosity at 100°C	≥6.v cSt.	Shear: CEC L-45-T-93. (twenty hr. KRL Method) Vis: ASTM D-445
Brookfield Viscosity at -40°C	≤17,500 centipoise	ASTM D-2983

Property	Target Value	Method of Measurement
Unsheared Kinematic Viscosity at 100°C	≥6.8 cSt.	ASTM D-445
Sheared Kinematic Viscosity at 100°C	≥vi.8 cSt.	Shear: ASTM D-5275. (FISST Method, 40 passes) Vis: ASTM D-445
Brookfield Viscosity at -twoscore°C	≤xiii,000 centipoise	ASTM D-2983

Property	Target Value	Method of Measurement
Unsheared Kinematic Viscosity at 100°C	≥seven.three cSt.	ASTM D-445
Sheared Kinematic Viscosity at 100°C	≥6.5 cSt.	Shear: CEC Fifty-45-T-93. (20 hr. KRL Method) Vis: ASTM D-445
Brookfield Viscosity at -twoscore°C	≤10,000 centipoise	ASTM D-2983

B. Base Oils

1. Low Viscosity Index Base Oil From Processed hydrocracker Bottoms

a. Hydrocracker Bottoms

The lubricating composition of the invention includes a hydrocracker-derived, highly naphthenic, depression viscosity index mineral oil. The term "low viscosity index" mineral oil as used in this specification and appended claims means mineral oils having viscosity indexes lower than as set forth beneath in the section on "high viscosity index" mineral oils. This hydrocracker-derived, highly naphthenic, low Half dozen mineral oil is prepared by catalytically dewaxing and hydrofinishing a hydrocracker bottoms fraction.
The meaning of the term "hydrocracker bottoms fraction" is more often than not known to those skilled in the fine art. By and large, a hydrocracker bottom fraction has a boiling point range from about 470°F to near 910°F, e.g., where about 5 wt. % boils at or below about 530°F and, eastward.1000., where 50 wt. % boils at or below about 675°F. Catalytic dewaxing and hydrofinishing, other than as utilized in the lubricating composition of this invention, are known generally to those skilled in the fine art. Catalytic dewaxing and hydrofinishing are taught, eastward.m., in U.S. Patent Nos. v,591,322; 5,149,421; and 4,181,598, the disclosures of which are incorporated herein by reference.
In fuel hydrocracker processes, certain fractions from the main or vacuum distillation columns for distilling crude oil are catalytically cracked to obtain fuels-range molecules. The heaviest fraction, i.e., the bottoms, from the hydrocracker is typically besides heavy for fuels employ. It is normally recycled to the hydrocracker feed for further keen. The hydrocracker bottoms are typically as well as well light for lubrication uses, although this is not always truthful for "in one case-through" units. Typically, even so, hydrocrackers operated to make fuels will "recycle to extinction" in gild to maximize the fuels product output. In the dewaxing step of the invention, at least a portion of this bottoms fraction recycle stream is passed to a catalytic dewaxing process.
Not more than near 67 wt. % of the recycle stream is passed to the dewaxing unit. Preferably, non more about 50 wt. % or non more than 33 wt. % of the recycle stream is passed to the dewaxing unit of measurement. Thus, at least about 33 wt. %, or preferably at least near 50 wt. % or near 67 wt. %, of the recycle stream is combined with the hydrocracker feed or otherwise returned to the hydrocracker for additional cracking/processing. The bottoms fraction in the recycle stream has a viscosity at 100°C which is typical of a hydrocracker operated in a manner for maximizing production of jet fuel and/or gasoline. Typically, such viscosity at 100°C is less than virtually 4.0 cSt and preferably less than about three.five cSt or three.3 cSt. Later catalytic dewaxing and catalytic hydrofinishing, the base oil has a naphthenes content of at least 23 wt. % or 25 wt. %, preferably at least 33 wt. %, 35 wt. %, or 37 wt. %. The term "naphthenes content" as used in this specification, including the claims, ways every bit measured past ASTM D-3238. To meet these special parameters, the hydrocracker will typically need to be operated in a manner typically consistent with optimizing fuels production.
This is in dissimilarity to a hydrocracker operated specifically for lubes production. A hydrocracker operated specifically for lubes production would take no recycle to the hydrocracker feed, a college viscosity of the bottoms, and lower naphthenes content. This is considering further keen of the molecules reduces viscosity and molecular weight downwardly to levels which are undesirable for lubes. It has been unexpectedly discovered, however, that using hydrocracker bottoms from a fuels hydrocracker operated primarily for fuels production gives unexpectedly useful backdrop to the bottoms, especially when mixed with other base oils and with Vi improvers.
In that procedure, the bottoms fraction is contacted with an, optionally, conventional dewaxing catalyst at catalytic dewaxing atmospheric condition, whereby at least a portion of the bottoms fraction is dewaxed. At least a portion of the resulting dewaxed effluent from the catalytic dewaxing process is then passed to catalytic hydrofinishing process for removal of sulfur, nitrogen, and aromatics. In the hydrofinishing process, the dewaxed effluent from the catalytic dewaxing process is contacted with an, optionally, conventional hydrofinishing catalyst at catalytic hydrofinishing conditions, whereby at least a portion of the sulfur, nitrogen, and/or aromatics is removed.
The hydrofinished effluent is and then fractionated by whatsoever conventional fractionation procedure, thereby producing at to the lowest degree one lighter fraction and ane heavier fraction. At least a portion of the lighter fraction is loftier purity, low cascade signal diesel/jet fuel. At least a portion of the heavier fraction is a hydrocracker-derived, highly naphthenic, depression viscosity alphabetize base oil for utilize in the automatic manual fluid of this invention.

b. Catalytic Dewaxing

The dewaxing process is conducted at catalytic dewaxing conditions. Such weather are known and are taught for example in U.S. Patent Nos. 5,591,322; 5,149,421; and 4,181,598, the disclosures of which are incorporated herein past reference. The catalytic dewaxing conditions are dependent in large measure on the feed used and upon the desired pour point. Hydrogen is preferably nowadays in the reaction zone during the catalytic dewaxing process. The hydrogen to feed ratio, i.e., hydrogen circulation rate, is typically between about 500 and about xxx,000 SCF/bbl (standard cubic feet per barrel), preferably almost one thousand to nigh 20,000 SCF/bbl. Generally, hydrogen will exist separated from the product and recycled to the reaction zone.
Goad bed arrangements suitable for use in dewaxing step of the invention are any conventional catalyst bed configuration. The catalytic dewaxing atmospheric condition employed depend on the feed used and the desired cascade indicate.
Generally, the process atmospheric condition for dewaxing processes are every bit follows: the temperature is from about 200°C and about 475°C, preferably betwixt about 250°C and about 450°C. The pressure is typically from about xv psig and about 3000 psig, preferably between nearly 200 psig and 3000 psig. The liquid hourly space velocity (LHSV) preferably volition be from 0.ane to 20, preferably between well-nigh 0.2 and 10.
Hydrogen is preferably nowadays in the reaction zone during the procedure. The hydrogen to feed ratio is typically between about 500 and about thirty,000 SCF/bbl (standard cubic anxiety per barrel), preferably from about chiliad to nearly twenty,000 SCF/bbl. Generally, hydrogen will exist separated from the product and recycled to the reaction zone.
Suitable aluminosilicate zeolite dewaxing catalysts for utilise in the dewaxing step of the invention include, e.chiliad., ZSM-48, SSZ-32, other dewaxing-capable zeolites, and mixtures thereof. These are taught in R. Szostak, Handbook of Molecular Sieves (Van Norstrand Reinhold 1992), at pages 551-553 and 172-174, which are incorporated herein by reference, and in U.S. Patent Nos. 5,053,373; 4,397,827; four,537,754; and four,593,138, the disclosures of which are incorporated herein by reference. Where two or more zeolite catalysts are employed, they are mixed in an effective weight ratio to enhance dewaxing. Preferred ratios for two zeolites are from near 1:v to most 20:1.
Any zeolite used in the process may optionally contain a hydrogenation component of the type commonly employed in dewaxing catalysts. See the same U.S. Patent No. 4,910,006 and U.S. Patent No. 5,316,753 for examples of these hydrogenation components, the disclosures of which are incorporated herein by reference.
The hydrogenation component is present in an effective amount to provide an effective hydrodewaxing catalyst preferably in the range of from about 0.01 to 10% by weight, more preferably from almost 0.05 to v% by weight. The catalyst arrangement may be run in such a fashion to increase dewaxing at the expense of nifty reactions.
Layered catalyst systems also may be used. For example, the catalyst system may take a first layer including, e.chiliad., zeolite SSZ-32, and at least one Group VIII metal, and a 2nd layer comprising another aluminosilicate zeolite, eastward.g., i which is more shape selective than zeolite SSZ-32. The employ of layered catalysts is disclosed in U.S. Patent No. 5,149,421, issued September 22, 1992 to Miller, which is incorporated by reference herein in its entirety. The layering may likewise include a shape-selective molecular sieve bed, eastward.g., SSZ-31, SSZ-32, SSZ-41, SSZ-43, ZSM-v, ZSM-12, SAPO-eleven, SAPO-31, SAPO-twoscore, SAPO-41, UDT-1,layered with a dissimilar component designed for either-hydrocracking or hydrofinishing, or any other catalyst having dewaxing activity with bright stocks. Intimately mixed goad systems represent another useful variant on this concept.
The aluminosilicate zeolite goad preferably contains i or more than Group VIII metals or other transition metals, such as platinum, palladium, molybdenum, nickel, vanadium, cobalt, tungsten, zinc, and mixtures thereof. More preferably, the intermediate pore size aluminosilicate zeolite goad contains at least 1 Grouping 8 metal selected from the group consisting of platinum and palladium. Most preferably, the intermediate pore size aluminosilicate zeolite catalyst contains platinum.
The amount of metal ranges from near 0.01% to about 10% past weight of the molecular sieve, preferably from nearly 0.2% to about five%, based on the weight of the molecular sieve. The techniques of introducing catalytically active metals to a molecular sieve are disclosed in the literature, and pre-existing metallic incorporation techniques and treatment of the molecular sieve to grade an active goad such as ion exchange, impregnation or occlusion during sieve preparation are suitable for use in the present process. Such techniques are disclosed in U.S. Pat. Nos. three,236,761; 3,226,339; 3,236,762; 3,620,960; 3,373,109; 4,202,996; four,440,781 and iv,710,485, the disclosures of which are incorporated herein past reference.
Catalysts useful in the dewaxing step typically comprise an agile material and a support or binder. The support for the catalysts of this invention may be the same as the active material and further tin can exist a synthetic or naturally occurring substance likewise as an inorganic textile such as dirt, silica and/or one or more metal oxides. The latter may be either naturally occurring or in the form of gelatinous precipitates or gels including mixtures of silica and metallic oxides.
Naturally occurring clays which tin can be used as support for the catalysts include those of the montmorillonite and kaolin families, which families include the subbentonites and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or others in which the master mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemic modification. In addition to the foregoing materials, the catalysts used in the dewaxing stride of this invention may be supported on a porous binder or matrix material, such as titania, zirconia, silica-magnesia, silica-zirconia, silica-thoria, silica-berylia, silica-titania, titania-zirconia, equally well as a ternary compound such every bit silica-magnesia-zirconia. A mixture of these components could also be used.
The support may exist in the form of a cogel. One binder that is suitable is a low acerbity titania prepared from a mixture comprising a low acidity titanium oxide binder fabric and an aqueous slurry of titanium oxide hydrate. Other binders include alumina and alumina-containing materials such as silica-alumina, silica-alumina-thoria, silica-alumina-zirconia, and silica-alumina-magnesia. Typical aluminas include alpha (blastoff) alumina, beta (beta) alumina, gamma (gamma) alumina, chi-eta-rho (chi, eta, rho) alumina, delta (delta) alumina, theta (theta) alumina, and lanthanum beta (beta) alumina. The preferred support is one that is a high surface area material that too possesses a high temperature stability and farther possesses a high oxidation stability.
The binder may be prepared according to U.Southward. Pat. No. 5,430,000, incorporated by reference herein, or may be prepared according to methods disclosed in U.Due south. Pat. Nos. 4,631,267; 4,631,268; iv,637,995; and 4,657,880, each incorporated by reference herein. Also, the catalysts described herein may be combined with any of the binder precursors described in the higher up patents, and then may be formed, such as past extrusion, into the shape desired, and then finished in a humidified atmosphere every bit hereinafter described.

c. Hydrofinishing

The balmy hydrogenation pace, hydrofinishing footstep, is beneficial in preparing an passably stable hydrocracker-derived, highly naphthenic, low VI base oil since unsaturated products tend to be unstable to air and low-cal and tend to degrade. Hydrofinishing is typically conducted at temperatures ranging from about 190°C to about 340°C, at pressures of from nigh 400 psig to about 3000 psig, at space velocities (LHSV) of from most 0.one to most 20, and hydrogen recycle rates of from nearly 400 to virtually 15000 SCF/bbl. The hydrogenation goad employed must exist active enough non only to hydrogenate the olefins and diolefins within the lube oil fractions, but also to reduce the content of any aromatics (color bodies) present.
Suitable hydrogenation catalysts include conventional, metallic hydrogenation catalysts, particularly the Group VIII metals such as cobalt, nickel, palladium and platinum. The metals are typically associated with carriers such every bit bauxite, alumina, silica gel, silica-alumina composites, and crystalline aluminosilicate zeolites and other molecular sieves. Palladium, platinum, and mixtures thereof are particularly preferred hydrogenation metals. If desired, not-noble Grouping Eight metals tin can be used with molybdates or tungstates. Metal oxides, due east.grand., nickel/cobalt promoters, or sulfides tin can be used. Suitable catalysts are disclosed in U.Southward. Pat. Nos. 3,852,207; 4,157,294; 4,921,594; 3,904,513 and 4,673,487, the disclosures of which are incorporated herein by reference.

2. High Viscosity Alphabetize Base Oil

The lubricating oil base of operations oil mixture of the invention contains i or more high viscosity index mineral oils. Such high viscosity index mineral oils are paraffinic. The terms "high viscosity index" mineral oil and "unconventional mineral base oil" do non have strict definitions. In general, they refer to mineral base oils having desirable viscometric properties non typically constitute in mineral oils and more often than not only available in expensive constructed base oils. The market place recognizes the desirability of viscometric properties of loftier-viscosity index and unconventional mineral oils in that they control a higher price than "conventional" mineral oils. Thus, the relative price is also an indicator of unconventional and high viscosity base index oils. To avoid ambiguity, the term "high viscosity index" mineral oil as used in this specification and appended claims means (1) a viscosity index of at least 90 for a mineral oil having a viscosity of 3.0 centistokes at 100°C; (2) a viscosity index of at least 105 for a mineral oil having a viscosity of 4 centistokes at 100°C; (three) a viscosity index of at least 115 for a mineral oil having a viscosity of 5.0 centistokes at 100°C; and (4) a viscosity index of at to the lowest degree 120 for a mineral oil having a viscosity of 7.0 centistokes at 100°C. "High" viscosity indices for other viscosities between 3.0 and vii.0 tin be determined by conventional interpolation.
The viscosity indices of the loftier Half-dozen base oils used in the nowadays invention are much higher than those commonly used in the manufacture. The "high viscosity index" base of operations oils used in the present invention are also referred to as "Unconventional Base Oils". The preferred method of manufacture for the Unconventional Base Oils is a combination of hydrocracking followed by catalytic dewaxing. Two such processes for preferred base oil industry are licensed under the names of ISOCRACKING and ISODEWAXING.

3. Other Depression Viscosity Alphabetize Base Oil

I or more than embodiments of the invention include a conventional low viscosity index mineral oil, i.east., one other than the hydrocracker-derived, highly naphthenic, low VI base oil discussed to a higher place. The term "conventional" as used in this specification means previously known or used in the lubes art.
Preferred embodiments of the lubricating composition of the invention contain one high VI mineral oil and one low VI mineral oil, where the depression Six mineral oil is obtained from hydrocracker bottoms as described above. In ane apotheosis, the high viscosity index mineral oil has a viscosity of at least almost 5.0 cSt at 100°C. The low Vi mineral oil has a viscosity of at to the lowest degree about 3.0 cSt at 100°C. More preferably, the high viscosity index mineral oil has a viscosity of at least about 6.5 cSt at 100°C and the depression viscosity index mineral oil has a viscosity of at least 3.7 cSt at 100°C. The weight ratio of the high VI mineral oil to the low VI mineral oil is from well-nigh 0:100 to near ninety:10, preferably from about 80:20 to nigh 20:lxxx, or from seventy:thirty to virtually 30:70, or from about 60:40 to about twoscore:60.
The base oil mixture of the invention provides for skilful low temperature operation while maintaining a minimum oil film thickness to protect moving parts such as bearings and gears. The low Vi mineral oil component enables the finished oil to reach a low pour point and a maximum Brookfield viscosity as set forth in the respective viscometric operation specifications shown in Tables 1-four in a higher place. The loftier VI mineral oil component provides the necessary oil film thickness to protect moving parts at high temperatures. Neither base oil component alone would impart all season backdrop to the finished oil.
The viscosity alphabetize improver is one component or, optionally, a blend of two or more components. The VI improvers optionally take a shear stability index of less than virtually 30. The terms "sheared", "shear stability alphabetize (SSI)", and "shear stability" every bit used in this specification and appended claims each mean as measured by the Sonic Shear Method as set forth in ASTM Test D-5621. The shear stability index is calculated as follows:
SSI = (Vi-Vf)*100/(Six-Vb),
where Vi is the initial viscosity in centistokes at 100°C of the fresh, unsheared automatic transmission fluid; Vf is the terminal viscosity in centistokes at 100°C of the automatic transmission fluid after the 40-minute D-5621 shear procedure; and Vb is the viscosity in centistokes at 100°C of the automatic transmission fluid base mixture without the viscosity alphabetize improvers added.
The total Six improver content is from most 2 to 14 wt. %. The VI improver(s), whether present individually or in combination, are present in sufficient amounts and then that said automated transmission fluid composition has the viscometric backdrop of one or more than of the sets of viscometric performance specifications shown in Tables 1-4 higher up.
Polymethacrylate viscosity index improvers are commercially available. The lubricating composition will typically include a performance additive package. The term "performance additive package" as used in this specification and appended claims ways any combination of other conventional additives for lubricating compositions. Such additives include corrosion and rust inhibitors, anti-oxidants, dispersants, detergents, anti-cream agents, anti-wear agents, friction modifiers and flow improvers. Such additives are described in "Lubricants and Related Products" by Dieter Klamann, Verlag Chemie, Deerfield Beach, Fla., 1984.

V. ILLUSTRATIVE EMBODIMENTS

The invention will be further clarified past the post-obit Illustrative Embodiments, which are intended to exist purely exemplary of the invention. The results are shown in Tables 5 to 10 below.
The components used to blend the various automatic transmission fluid compositions for the Illustrative Embodiments and Comparative Examples are shown beneath:

"Low VI Base of operations Oil A₁ and A₂" - are hydrocracker-derived, highly naphthenic, depression viscosity index base oils prepared from a hydrocracker bottoms according to the steps of the invention. Low VI Base Oils A₁ had a viscosity of about iii.3 cSt at 100°C and a viscosity alphabetize of 83. Low VI Base Oils A₂ had a viscosity of nearly 3.iii cSt at 100°C and a viscosity index of 86.
"Low Half-dozen Base Oil B" - a conventional low viscosity index mineral base of operations oil having a viscosity of about 4.ane cSt at 100°C and a viscosity index of 99.
"Loftier Half dozen Base Oil A" - a high viscosity alphabetize mineral base of operations oil having a viscosity of about four.2 cSt at 100°C and a viscosity index of 129.
"High VI Base Oil B" - a high viscosity index mineral base oil having a viscosity of well-nigh 5.6 cSt at 100°C and a viscosity alphabetize of 117.
"Half dozen Improvers A, B, and C" - are commercially available polymethacrylate viscosity index improvers.
"Performance Additive Packages A and B" - a commercially available additive bundle containing such components as anti-wear agent, detergent, anti-rust agent, copper corrosion inhibitor, antioxidant, friction modifier, cascade point depressant and anti-foam.

The results of the Illustrative Embodiments in Tables 5, 6 and vii show the effects of diverse mixtures of components. In particular, the upshot of adding Low Viscosity Alphabetize Base of operations Oil A_one is of involvement, i.e., a hydrocracker-derived, highly naphthenic, depression Half-dozen base oil of the invention. In Table 5, the concentration of Low Viscosity Index Base Oil A_i, in mixture with Low Viscosity Index Base Oil B, was steadily increased over 4 test runs. The results evidence that increasing the concentration of Low Viscosity Index Base Oil A₁ resulted in a decreased Brookfield Viscosity at -forty°C, increased VI, and decreased Viscosity at 100°C. In Table 5, runs two and 3 meet the viscometric performance specifications shown in Table ii above.
In Table 6 and seven, the concentration of Low Viscosity Index Base Oil A₁, in mixture with High Viscosity Index Base Oils A or B, was steadily increased. The results show that increasing the concentration of Low Viscosity Index Base Oil A resulted in a decreased Brookfield Viscosity at -40°C decreased VI and decreased Viscosity at 100°C.
Every bit shown in Tables vi and 7, increasing quantities of Low Viscosity Index Base Oil A₁ resulted in increased coming together of the target viscometric operation specifications. In Table vii, run 1 meets the target viscometric performance specifications shown in Table ii above.
Table 8 shows the higher naphthenes content of 1 embodiment of the hydrocracker-derived, highly naphthenic, low Half-dozen mineral base oil of the invention in comparison to other commercially available catalytically dewaxed base oils and one solvent dewaxed base oil. Base oils Thou, N, O, and P are ATF base oils made from hydrocrackers. Their naphthene content is much lower than in the hydrocracker-derived, highly naphthenic, low VI mineral base oil of the invention. The naphthenes content of base of operations oil Q is close to that of the hydrocracker-derived, highly naphthenic, depression Half-dozen mineral base oil of the invention. However, base oil Q is a solvent refined ATF base of operations oil and so also has higher aromatics content which is undesirable since that tends to cause poor oxidation stability.
Tabular array 9 shows how the viscometric operation of the hydrocracker-derived, highly naphthenic, low viscosity index base oil of the invention compares with the viscometric performance of a solvent dewaxed depression viscosity index base oil having a similar naphthenes content (i.e., Low VI Oil Q in Tabular array viii). Even though the solvent dewaxed base of operations oil has a like naphthenes content and has a slightly higher Half-dozen and viscosity, its viscometric properties are not equally good for making ATF as the hydrocracker-derived, highly naphthenic, depression viscosity alphabetize base of operations oil of the invention, i.e., a Brookfield viscosity of 18,120 versus 34,350. This is surprising behavior which is believed to exist due at least in part to an unexpected beneficial effect of Isocracking and Isodewaxing compared to solvent refining.
If we modify the Half-dozen Improver, as in runs three and 4, we tin further better the viscometric performance of the hydrocracker-derived, highly naphthenic, low viscosity index base of operations oil of the invention so that the Brookfield viscosity meets at to the lowest degree one of our preferred embodiments, i.e., the performance specifications in Tables 1-four above. Every bit shown, run i is very shut to meeting the target viscometric functioning specifications shown in Table ii above. In comparing, blend 2, the solvent-dewaxed base oil, is far from it. Blends 3 and iv each meet the target viscometric functioning specifications shown in Table 2 above.
The results in Tabular array 10 bear witness what was known, i.e., that a high VI oil can make a very good ATF. Table ten also shows results that were unexpected withal. By calculation increasing amounts of the hydrocracker-derived, highly naphthenic, low viscosity alphabetize base oil of the invention, we can go on to make adept ATF. As we add more of the hydrocracker-derived, highly naphthenic, low viscosity index base oil of the invention, nosotros need to use more VI Improver to maintain a satisfactory Brookfield viscosity. Since the manufacturing cost of the high 6 base oil is higher than the manufacturing cost of the hydrocracker-derived, highly naphthenic, low viscosity alphabetize base oil of the invention, it is unexpected that we can use the hydrocracker-derived, highly naphthenic, depression viscosity index base oil of the invention every bit a blending component to reduce the cost of the finished ATF.
Every bit shown, each blend in Tabular array 10 meets either the target viscometric functioning specifications shown in Table 2 above.

Claims

A lubricating composition comprising:

(a) a major amount of a base oil mixture comprising:

(i) from most 0 wt. % to near xc wt. % of a kickoff mineral oil selected from a high viscosity alphabetize mineral oil, a conventional low viscosity index mineral oil, and mixtures thereof; and

(2) from well-nigh 10 wt. % to about 100 wt. % of a second mineral oil comprising a hydrocracker-derived, highly naphthenic, depression viscosity alphabetize mineral oil prepared by:

(i) passing a first bottoms portion comprising not more than than about 67 wt. % of a fuels hydrocracker bottoms recycle stream to a dewaxing zone; and passing a second bottoms portion comprising at least nigh 33 wt. % of said recycle stream back to said fuels hydrocracker for boosted processing; and wherein said recycle stream has a viscosity at 100°C of less than almost 4.0;

(ii) contacting said outset bottoms portion with a dewaxing goad under catalytic dewaxing conditions, wherein at to the lowest degree a portion of said hydrocracker bottoms is essentially dewaxed;

(three) contacting at least a portion of said substantially dewaxed hydrocracker bottoms with a hydrofinishing catalyst nether hydrofinishing conditions, thereby producing a hydrofinished, dewaxed hydrocracker bottoms; and

(iv) removing from said hydrofinished, dewaxed hydrocracker bottoms at least i light fraction comprising diesel fuel or jet fuel range fabric, thereby leaving a heavy fraction comprising said hydrocracker-derived, highly naphthenic, viscosity index mineral oil having a naphthenes content of at least about 33 wt. %;

(b) from nigh 2 wt. % to about xiv wt. % of at least one polymethacrylate polymer;

(c) from near 2 wt. % to virtually 14 wt. % of a performance additive package; and

(d) wherein said lubricating composition has:

(1) an unsheared kinematic viscosity at 100°C of at to the lowest degree about six.5 centistokes;

(2) a sheared kinematic viscosity at 100°C of at least nearly half dozen.five centistokes, wherein shear is measured by the 20 hour KRL method; and

(3) a Brookfield viscosity at -xl°C of no greater than well-nigh 17,500 centipoise.
The lubricating composition of claim 1, further comprising at to the lowest degree two of said polymethacrylate polymers comprising a first polymethacrylate polymer and a 2d polymethacrylate polymer.
The lubricating limerick of claim two, wherein said lubricating composition is an automatic transmission fluid limerick.
The lubricating composition of claim 1, wherein said polymethacrylate polymer is adapted for viscosity index comeback of a natural lubricating oil.
The lubricating composition of claim 3, wherein the weight ratio of said outset mineral oil to said hydrocracker-derived, highly naphthenic, low viscosity index mineral oil is from about 80:twenty to nearly xx:80.
The lubricating limerick of merits 3, wherein the weight ratio of said first mineral oil to said hydrocracker-derived, highly naphthenic, low viscosity index mineral oil is from nigh 70:30 to about 30:seventy; and wherein said hydrocracker-derived, highly naphthenic, low viscosity index mineral oil has a naphthenes content of at least almost 35 wt. %.
The lubricating composition of merits three, wherein the weight ratio of said first mineral oil to said hydrocracker-derived, highly naphthenic, low viscosity alphabetize mineral oil is from about threescore:40 to about 40:lx.
The lubricating composition of claim two, wherein said lubricating composition contains from almost 1 weight percentage to about 10 weight percent, based on the weight of said lubricating composition, of one polymethacrylate polymer and a diluent.
The lubricating limerick of claim ii, wherein said lubricating composition contains from nigh i weight percent to virtually 10 cumulative weight per centum, based on the weight of said lubricating composition, of two polymethacrylate polymer and a diluent.
The lubricating composition of claim 3, wherein said first mineral oil consists essentially of said conventional depression viscosity index mineral oil.
The lubricating composition of claim 1, wherein said first mineral oil consists essentially of said high viscosity alphabetize mineral oil, and wherein:

(a) said loftier viscosity alphabetize mineral oil has a kinematic viscosity at 100°C of at to the lowest degree about four.0 centistokes; and

(b) said hydrocracker-derived, highly naphthenic, low viscosity index mineral oil has a kinematic viscosity at 100°C of less than about 4.0 centistokes.
The lubricating limerick of claim i, wherein said get-go mineral oil consists essentially of said high viscosity index mineral oil, and wherein:

(a) said high viscosity index mineral oil has a kinematic viscosity at 100°C of at least about five.0 centistokes; and

(b) said hydrocracker-derived, highly naphthenic, depression viscosity index mineral oil has a kinematic viscosity at 100°C of less than nigh 3.5 centistokes.
The automated transmission fluid limerick of claim 10, wherein said automatic transmission fluid composition contains from about iv weight percent to about 8 weight percent, based on the weight of said automatic transmission fluid limerick, of said first polymethacrylate viscosity index add-on.
The automatic transmission fluid limerick of merits 10, wherein said automatic manual fluid composition contains from almost 2 weight percent to virtually five weight percent, based on the weight of said automated transmission fluid composition, of said 2nd polymethacrylate viscosity index improver.
A lubricating composition co-ordinate to any preceding claims wherein said lubricating composition has:

(1) an unsheared kinematic viscosity at 100°C of at least about 7.iii centistokes;

(2) a sheared kinematic viscosity at 100°C of at least about 6.8 centistokes, wherein shear is measured by the twenty-hr KRL method; and

(3) a Brookfield viscosity at-40°C of no greater than well-nigh 10,000 centipoise.
A lubricating composition according to whatsoever 1 of claims 1 to fourteen, wherein said lubricating composition has:

(1) an unsheared kinematic viscosity at 100°C of at least about 6.eight centistokes;

(2) a sheared kinematic viscosity at 100°C of at least about 6.8 centistokes, wherein shear is measured past the 20-hr KRL method; and

(3) a Brookfield viscosity at-forty°C of no greater than about xiii,000 centipoise.
A lubricating limerick according to any one of claims i to xiv, wherein said lubricating composition has:

(1) an unsheared kinematic viscosity at 100°C of at to the lowest degree about vii.3 centistokes;

(2) a sheared kinematic viscosity at 100°C of at least near 6.v centistokes, wherein shear is measured by the 20-hr KRL method; and

(three) a Brookfield viscosity at-40°C of no greater than most 10,000 centipoise.