ES2665459T3 - Lubricating compositions - Google Patents

Abstract

A lubricating composition for use in association with a device involving metal-to-metal contact of moving parts, which comprises: (a) 10-35% by weight of a low-viscosity polyalphaolefin: wherein said polyalphaolefin has a viscosity of not more than 12 centistokes cSt) at 100 ° C. (b) 30-75% by weight of a high-viscosity polyalphaolefin: where said high-viscosity polyalphaolefin has a viscosity of 40 to 1000 centistokes cSt) at 100 ° C. (c) 5-30% by weight of a selected diester from the group consisting of di-isodecyl adipate, diisodecyl azelate and ditridecyl adipate (d) 2-25% by weight polyisobutylene; (e) 5-10% by weight of additive package comprising at least one additive that is effective in improving at least one lubricating property and / or performance of the equipment in which the lubricant is to be used, and, optionally (f ) 0.001-0.004% by weight of an antifoaming agent; wherein the weight ratio of the low viscosity polyalphaolefin to the diester is 2.6: 1 to 1: 1.6; wherein said lubricating composition meets the American Petroleum Institute GL-5 performance classification requirements and is classified as SAE 75W-140.

Description

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DESCRIPTION

Lubricating compositions Field of the invention

The present invention relates to lubricating compositions that have utility in numerous applications, particularly in connection with gear, transmission and / or axle applications in the automobile and machinery industries

Background of the invention

An important function of lubricating compositions and, in particular, of lubricating fluids for gears and shafts is to provide a high degree of reliability and durability in the service life of the equipment in which they are installed. Lubricating oils in general and gear and shaft lubricants in particular often have to meet a large number of performance criteria to be commercially successful. For example, a successful axle lubricant will often require a high degree of oxidation stability, compatibility, shear stability, corrosion annulment or resistance to corrosion, wear protection, extended maneuverability and replacement. . These properties represent a set of performance criteria that is difficult to achieve.

Lubricating gear compositions are classified by the American Petroleum Institute ("API") using the "GL" classification. This classification is subdivided into six classes. The lowest classification, API GL-1, classifies oils used for light conditions consisting of base oils without additives. The highest classification, API GL-6, classifies oils for very heavy conditions, such as high sliding speeds and significant impact loading, and which contain up to 10% high performance anti-scratch additives. However, the API GL-6 class no longer applies since the API GL-5 class is considered to meet most of the most severe requirements. Classified lubricating compositions that meet the performance requirements of API GL-5 are generally applied, for example, to hypoid gears that have significant shaft displacement.

The viscosity-temperature ratio of a lubricant composition is another critical criteria to consider when selecting a lubricant for a particular application. Commonly used mineral oils as a base for simple or multigrade lubricants exhibit a relatively large change in viscosity with a change in temperature. Fluids that exhibit such a relatively large change in viscosity with temperature have a low viscosity index. The SAE J306 describes viscosimetric ratings for lubricating compositions for shafts and gears. This classification is based on the viscosity of the lubricant measured at both high and low temperatures. High temperature kinematic viscosity values are determined according to ASTM D 445, with the results reported in centistokes (cSt). Low temperature viscosity values are determined according to ASTM D 2983 and the results are reported in centipoise (cP). These 2 U viscosity are related as follows in equation 1:

(cP / (Density, g / cm3)) = cSt (Ec. 1)

The following table 1 compiles high and low temperature requirements for grades of lubricating compositions for shafts and gears.

Table 1

 SAE viscosity grade

 Maximum temperature for Viscosity at 100 ° C, cSt

 Viscosity of 150,000 cP, ° C Minimum Maximum

 70W

 -55 4.1 -

 75W

 -40 4.1 -

 80W

 -26 7.0 -

 85W

 -12 11.0 -

 80

 - 7.0 <11.0

 85

 - 11.0 <13.5

 90

 - 13.5 <18.5

 110

 - 18.5 <24.0

 140

 - 24.0 <32.5

 190

 - 32.5 <41.0

 250

 - 41.0 -

These standards of the Society of Automotive Engineers ("SAE") are intended for use by equipment manufacturers when defining and recommending lubricants for gears, shafts and manual transmissions in cars,

for oil sellers when labeling such lubricants with respect to their viscosity and for users when following their recommendations in their owner's manuals.

High temperature viscosity refers to the characteristics of hydrodynamic lubrication of the fluid. Some lubricating compositions may contain high molecular weight polymers, known as viscosity modifiers or viscosity index improvers, which function to increase fluid viscosity. During use, however, these polymers can be cut at a lower molecular weight, whereby they give rise to a fluid with a lower viscosity than that of the new fluid. The low temperature viscosity requirements refer to the ability of the fluid to flow and provide adequate lubrication to critical parts in low ambient temperature conditions.

Although a substantial amount of lubricant compositions have been produced that have various necessary properties where such lubricant compositions are used, there is a need for an additive or a combination of additives to provide a clean, improved performance lubricant composition that can be used. While the acceptable performance of gear oil is a requirement, it is also highly desirable that the additive or additives have low costs be easily produced. Therefore, there is a need in the technique of a lubricating composition that meets these industry standards and also provides cost-effective alternatives that can be easily produced and, in particular, lubricant compositions classified as SAE 75W-140 and that meet performance requirements. of GL-5.

Summary of the invention

Applicants have developed improved lubricant compositions, and in many embodiments, 20 lubricant compositions that meet a relatively high level of performance for the criteria mentioned above. As used herein, the term "lubricant composition" is used in its broadest sense to include fluid compositions that are used in applications involving metal-to-metal contact of the components in which at least one function of the fluid is to inhibit or reduce friction between the components. As such, the term "lubricant composition", as used herein, includes 25 gear oils, shaft oils and the like.

In some embodiments, the lubricating compositions of the present invention comprise: (a) basic component; (b) viscosity improver; and (c) at least one additive. The lubricating compositions of the present invention comprise: (a) basic component comprising (i) a low viscosity polyalphaolefin ("PAO"), and (ii) at least one diester; (b) a viscosity improver comprising (i) at least one viscosity improver of relatively high viscosity PAO type, and (ii) polyisobutylene; and (c) a performance additive package comprising at least one additive that is effective in improving at least one property of the lubricant and / or the performance of the equipment in which the lubricant is to be used. The lubricant compositions of the present invention are multiviscous quality lubricants that have an SAE viscosity rating of 75W-140, and meet the performance requirements of API GL-5.

Applicants have found that the present lubricant compositions, as defined in claim 1, that have an SAE viscosity rating of 75W-140 and that meet the performance requirements of API GL-5 comprise:

(a) 10-35% by weight of a low viscosity PAO;

(b) 30-75% by weight of a high viscosity PAO;

40 (c) 5-30% by weight of a diester;

(d) 2-25% by weight of GDP;

(e) 5-10% by weight of an additive package; and optionally

(f) 0.001-0.004% by weight of an antifoaming agent.

Applicants have found that some SAE 75W-140 lubricant compositions of the present invention 45 meet the performance requirements of API GL-5 and provide cost-effective lubricant compositions that exhibit improved performance in crown and pinion gears with respect to one or more , and preferably all, the following advantageous properties: striated, wavy, chopped, flaked, scratched and wear.

Detailed description of the preferred embodiments

The present invention is directed in one aspect to lubricating compositions comprising: (a) basic component; (b) viscosity improver; and (c) at least one additive. The lubricant composition is a multivisk quality quality lubricant that has an SAE viscosity rating of 75W-140, and meets API GL-5 performance requirements. The basic component of the present invention comprises: (i) a low viscosity polyalphaolefin ("PAO"); and (ii) at least one diester. The viscosity improver of the present invention comprises: (i) at least one PAO type viscosity improver of relatively high viscosity; and (ii) polyisobutylene. The additive package of

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performance comprises at least one additive that is effective to improve at least one property of the equipment in which the lubricant is to be used.

In general, it is contemplated that these components of the present invention may be present in compositions in widely varying amounts depending on the particular needs of each application and all these variations are considered within the broad scope of the invention. However, applicants have found that in some embodiments the present lubricant compositions comprise:

(a) 15-65% by weight of basic component;

(b) 30-75% by weight viscosity improver; Y

(c) 7-35% by weight of additive.

Applicants have found that lubricating compositions of the present invention, when used in connection with crown and pinion gears, exhibit and / or produce advantageous properties with respect to one or more, and preferably all of the following: striated, corrugated, chopped , scaled, scratched and wear.

The PAOs of the present invention comprise a class of hydrocarbons that can be manufactured by catalytic oligomerization (low molecular weight polymerization processes) of linear a-olefins that typically range from 1-octene to 1-dodecene, where 1-decene is a material preferred, although polymers of lower olefins, such as ethylene and propylene, including copolymers of ethylene with higher olefins can also be used. In general, numerous particular compounds or combinations of compounds are available for use in connection with each of the components, as described herein.

In one embodiment, the basic component of the present invention comprises at least one relatively low viscosity PAO and at least one diester. With respect to the low viscosity PAO of the present invention, the low viscosity PAO comprises a polyalphaolefin having a viscosity not greater than 12 cSt at 100 ° C. In one embodiment, the low viscosity PAO of the present invention comprises PAO-2 from ChevronPhillips and PAO-6 from Ineos. Other examples of such low viscosity PAOs should be apparent to someone moderately skilled in the art. With respect to the diester of the present invention, in one embodiment, the diester comprises an adipate ester. The adipate ester comprises an ester selected from the group consisting of diisodecyl adipate, di-isodecyl azelate azelate and di-tridecyl adipate. While it is contemplated that a large range of relative concentrations of such components may be present, in general the basic component of the present invention comprises a low viscosity PAO weight ratio: ester from 2.6: 1 to 1: 1.6 . The lubricating compositions of the present invention comprise a low viscosity PAO in an amount of 10-35% by weight, and in other embodiments of 12-20% by weight. The lubricating compositions of the present invention comprise a diester in an amount of 5-30% by weight, and in other embodiments of 7.5-20% by weight. The viscosity improver of the present invention comprises at least one relatively high viscosity PAO and polyisobutylene. With respect to the relatively high viscosity PAO of the present invention, in some embodiments, the high viscosity PAO comprises a polyalphaolefin having a viscosity of 40 to 1000 cSt at 100 ° C. In one embodiment, the high viscosity PAO of the present invention comprises PAO-100 from ExxonMobil or Chemtura. Other examples of such high viscosity PAOs should be apparent to someone moderately skilled in the art. With respect to the polyisobutylenes of the present invention, in some embodiments the polyisobutylene comprises H-1500-SPA of Ineos or Lubrizol 8404. Other examples of such polyisobutylenes should be apparent to someone moderately skilled in the art. While it is contemplated that a large range of relative concentrations of such components may be present, in general the viscosity improver of the present invention comprises in some embodiments a weight ratio of high viscosity PAO: polyisobutylene from 37.5: 1 to 1.2: 1, and preferably from 12: 1 to 2.6: 1. The lubricating compositions of the present invention comprise a high viscosity PAO in an amount of 30-75% by weight, and in other embodiments of 40-60% by weight. The lubricating compositions of the present invention comprise polyisobutylene in an amount of 2-25% by weight, and in other embodiments of 5-15% by weight. The at least one performance additive of the invention comprises a performance additive package comprising at least one additive that is effective in improving at least one property of the lubricant and / or the performance of the equipment in which the lubricant is to be used. In some embodiments, the yield additive comprises at least one additive based on sulfur chemistry and at least one additive based on phosphorus chemistry. A typical additive package would normally contain one or more of a dispersant, antioxidant, corrosion inhibitors, anti-wear agent, anti-corrosive agent and extreme pressure agent. In one embodiment, the additive package comprises HiTec 317 from Afton. Other examples of such additives should be apparent to someone moderately skilled in the art. In some embodiments, the additive package optionally comprises an antifoaming agent. In other embodiments, the antifoaming agents comprise silicones and various organic compounds. In other embodiments, the antifoaming agent comprises lower molecular weight dimethyl siloxane. In one embodiment, the antifoam agent comprises Dow Corning DC-200/300 at 60,000 cSt. Other examples of such antifoaming agents should be apparent to someone moderately skilled in the art. The compositions

Lubricants of the present invention comprise an additive package in an amount of 5-10% by weight and in other embodiments of 7.5-9% by weight. The lubricating compositions of the present invention comprise an antifoaming agent in an amount of 0.001-0.004% by weight.

The present lubricant compositions can be prepared by mixing the components together at a temperature from about 35 ° C to about 95 ° C, preferably from about 65 ° C to about 85 ° C. The basic components, viscosity improvers and additives are placed in a suitable metal or glass container. Mechanical agitation is supplied to promote mixing. Sufficient mixing time is used to ensure that a homogeneous product is present. The process for making the lubricant compositions of the present invention should be known and appreciated by someone fairly skilled in the art, given the present disclosure. Someone moderately skilled in the art would appreciate that this preparation procedure does not limit the invention and that one or more components can be modified according to the teachings of this document or that are known in the art.

The lubricant compositions of the present invention preferably meet the requirements of both low temperature grade lubricants and high temperature grade lubricants, and in some embodiments are multiviscous grade lubricants. The lubricant compositions of the present invention are classified as SAE 75W-140 lubricants and meet the low temperature requirements for SAE 75W and the high temperature requirements for SAE 140. The lubricant compositions classified as SAE 75W have a viscosity of 150,000 cP a -40 ° C The lubricating compositions classified as SAE 140 are those that have a kinematic viscosity at 100 ° C of at least 24.0 cSt and less than 32.5 cSt. The lubricant compositions 20 of the present invention meet performance requirements of API GL-5 category and in other embodiments meet SAE J2360 performance standard. Some lubricant compositions of the present invention are intended for gears. In one embodiment, the lubricant compositions are intended for gears in automobile axles equipped with hypoid gears operating under various combinations of high speed / impact loading conditions and low speed / high torque. The lubricating compositions 25 of the present invention meet the performance requirements of API GL-5 category summarized by the following tests and acceptance criteria: (1) standard version of L-42; (2) Canadian version of L-42; (3) standard version of the ASTM D 6121 test procedure; (4) Canadian version of the ASTM D 6121 test procedure; (5) ASTM D 7038 or L-33 test procedure; (6) ASTM D 5704 or L-60 test procedure; (7) ASTM D 892 test procedure; and (8) ASTM D 130 test procedure.

In some other embodiments of the present lubricant composition it comprises:

(a) 12-20% by weight of the low viscosity PAO;

(b) 40-60% by weight of the high viscosity PAO;

(c) 7.5-20% by weight of the diester;

(d) 5-15% by weight of GDP;

35 (e) 7.5-9% by weight of the additive package; and optionally

(f) 0.001-0.004% by weight of an antifoaming agent.

Examples

The following examples are provided for the purpose of illustrating the present invention, but without limiting the scope thereof.

The exemplary lubricant composition 1 was prepared by mixing the components together as shown in table 2 as follows.

Table 2

 Component

 Composition Quantity (% by weight)

 Base component

 Low viscosity 23

 (73.9% of PAO-2 from ChevronPhillips, 26.1% PAO- 6 from Ineos)

 Base component

 Diester (Cognis Synative 2970 / diisodecyl adipate) 14

 Viscosity improver

 High viscosity PAO (ExoPo-100 or Chemtura PAO-100) 45

 Viscosity improver

 Polyisobutylene (Ineos H-1500-SPA) 10

(continuation)

 Additive

 API GL-5 Additive Package (Afton HiTec 317) 8.5

 Additive

 Antifoam additive (Dow Corning DC- 200 / 60,000) 0.002

Performance of axle lubricating compositions in high speed conditions and impact loading: L-42 (ASTM D 7452)

The objective of this procedure is to evaluate the anti-scratch properties of gear lubricants in 5 high speed and impact conditions. The performance of the process lubricants is compared with that of the reference oils. A specially selected rear axle installation assembly and two dynamometers serve as the procedure apparatus. A performance test is carried out at moderate speed and load at a lubricant temperature of 225 ° F (107.2 ° C). This is followed by a series of moderate accelerations and decelerations with temperatures approaching 280 ° F (137.8 ° C). The final series 10 of runs consists of high-speed accelerations with rapid decelerations. This test can be performed under two different sets of operating conditions, commonly referred to as "standard" and "Canadian." The crown and pinion gears are evaluated based on a test criteria passed / test not passed. The test criteria passed / test not passed require that there is less scratching on the crown and pinion gears, than in the associated test procedure of the associated reference oil. "Scratched", with respect to crown and pinion gears, as defined by ASTM D 7450, is the rapid removal of metal from tooth surfaces that are caused by the release of small contact particles that have been welded jointly as a result of metal to metal contact; A scratched surface is characterized by a matt or opaque finish. The results of the L-42 tests, standard and Canadian, are reported in the following tables 3 and 4, respectively.

20 Table 3

 Standard test L-42

 Example 1 Reference

 % scratched, pinion

 Transmission side

 0 0

 Cost side

 16 22

 % scratched, crown

 Transmission side

 0 0

 Cost side

 10 16

Table 4

 L-42 Canadian Test

 Example 1 Reference

 % scratched, pinion

 Transmission side

 0 0

 Cost side

 10 22

 % scratched, crown

 Transmission side

 0 0

 Cost side

 6 16

As can be seen in Tables 3 and 4 above, the lubricant composition according to the present invention passes the L-42 test, both standard and Canadian, by exhibiting a scratch equal to or better (lower) than the 25 average scratch values the reference oil test results that pass the test, used to calibrate the standard.

Performance of lubricating compositions high speed, low torque, followed by low speed, high torque: ASTM D 6121

This procedure is used to determine the load, wear and extreme pressure transport characteristics of gear lubricants in hypoid axle assemblies in high speed, low torque and low speed, high point torque conditions. A specially selected rear axle, engine and transmission assembly and two large dynamometers serve as the device for the procedure. The process axis is operated for 100 minutes at 440 rpm of the example, lubricant temperature of 295 ° F (146.1 ° C) and 9460 Ib-inch (109 m kg) of part forces. The example is then operated for 24 hours at 80 rpm of people, a lubricant temperature of 275 ° F (135.0 ° C), and 41,800 Ib-inch (482 m kg) of part forces. Crown and pinion gears are evaluated for a merit classification of ASTM based on spline, corrugated, wear, chopped / scaled and scratched.

With respect to the crown and pinion gears, as defined by ASTM D 7450, "striatum" is the alteration of the surface of the teeth to give a series of high, polished, parallel grooves, running diagonally in the direction of the sliding movement, either partially or completely through the surface of the teeth or gears. With respect to the crown and pinion gears, as defined in ASTM D 7450, 5 "wavy" refers to an alteration of the surface of the teeth that results in a more or less regular pattern appearance that is It resembles ripples on water or the scales of a fish. With respect to crown and pinion gears, as defined by ASTM D 7450, "wear" is the removal of metal, without evidence of surface fatigue or adhesive wear, which results in the partial or complete removal of tool marks or abrasion or the development of a discernible shoulder roughness in the lower part of the area near the root or at the end of the toe or heel of the pinion teeth contact area (abrasion wear) . With respect to crown and pinion gears, as defined by ASTM D 7450, "chopped" refers to small irregular cavities on the surface of the teeth that result in the disintegration of small areas of the metal surface. With respect to crown and pinion gears, as defined by ASTM D 7450, "scaling" is the appearance of scales of irregular surface area of the teeth, a condition more extensive than pitting. With respect to the crown and pinion gears, as defined by ASTM D 7450, "scratched" is the rapid removal of metal from the surface of the teeth caused by the tearing of small contact particles that have been welded together as result of a metal to metal contact; A scratched surface is characterized by a matt or opaque finish.

This test was performed in two different sets of operating conditions, called "standard", 20 using "non-lubricated" tools, and "Canadian", using "lubricated" tools. As defined by ASTM D 7450, "lubricated" refers to a phosphate coated surface. The results of the ASTM D 6121 standard, non-lubricated and Canadian tests that were carried out are reported in the following tables 5 and 6, respectively.

Table 5

 Test ASTM D 6121 (Standard, Not Lubricated) Example

 Example 1 Minimum Requirement

 Crown (ASTM Merit Rating)

 Pinion (ASTM Merit Rating) Crown (ASTM Merit Rating) Pinion (ASTM Merit Rating)

 Fluted

 10 8 8 8

 Curly

 10 9 8 8

 Wear

 8 8 5 5

 Chopped / Scaled

 9.9 9.9 9.3 9.3

 Lined

 10 10 10 10

25

Table 6

 ASTM D 6121 Test (Standard, Not Lubricated) Example

 Example 1 Minimum requirement

 Crown (ASTM Merit Rating)

 Pinion (ASTM Merit Rating) Crown (ASTM Merit Rating) Pinion (ASTM Merit Rating)

 Fluted

 10 8 8 8

 Curly

 10 9 8 8

 Wear

 8 8 5 5

 Chopped / Scaled

 9.9 9.9 9.3 9.3

 Lined

 10 10 10 10

As can be seen in Tables 5 and 6 above, the lubricant composition according to the present invention passed the standard and Canadian tests of ASTM D 6121 by exhibiting a merit rating of 30 ASTM equal to or better (higher) than the ratings specified minimums.

Performance of lubricating compositions while undergoing contamination with water and at elevated temperature: ASTM D 7038

This procedure is used to evaluate the corrosion and oxidation inhibition properties of a gear lubricant while undergoing contamination with water and at an elevated temperature. An electric motor, a specially selected hypoid differential housing assembly, a cooling fan, heating lamps and heated storage box serve as the apparatus for the procedure. The differential housing assembly is operated for 4 hours at 2500 rpm inlet, at a lubricant temperature of 180 ° F (82.2 ° C) with 1 fluid ounce of distilled water mixed in the lubricant. The procedure unit is then placed in the storage box and stored for 162 hours at 125 ° F (51.7 ° C). At the end of the procedure,

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The parts of the process assembly are qualified by the presence of rust. All internal moving parts (crown, pinion, bearings, differential gears, etc.) are evaluated by a qualification for final oxidation merits.

API GL-5 category candidate fluids are required to have a final oxide corrosion merit rating of 9.0 or more. Exemplary lubricant composition 1 passed the ASTM D7 1038 test by exhibiting a final merit corrosion rating of 9.3.

Thermal and oxidizing stability of lubricating compositions: ASTM D 5704

This procedure is used to determine the deterioration of lubricants under severe thermal and oxidant conditions. A gearbox assembly, two gears, two copper strips, a bearing, a temperature control system, an alternator, an engine and a regulated air supply serve as the main components for the installation of the procedure. Toothed gears are rotated under a load at 1750 rpm for 50 hours. The lubricant temperature is maintained at 325 ° F (162.8 ° C). The air flow through lubricant is controlled at 22.1 mg / min for the duration of the procedure. The physical and chemical properties of the oil and the deposits on the gears are evaluated at the end of the procedure. Large and small gears for coal / varnish and mud are evaluated. The oil used is evaluated for any increase in viscosity, insoluble in pentane and insoluble in toluene. The results of the ASTm D 5470 test performed are reported in Table 7 as follows.

Table 7

 ASTM D 5704 test

 Example 1 API GL-5 Requirement

 Increase in viscosity,%

 16 <100

 Insoluble in pentane,% by weight

 0.5 <3.0

 Insoluble in toluene,% by weight

 0.7 <2.0

 Coal / varnish

 7.8> 7.5

 Mud

 9.4> 9.4

As can be seen in Table 7 above, the lubricating composition according to the present invention passes the ASTM D 5704 test by exhibiting a% increase in viscosity,% by weight of insolubles in pentane and toluene, and carbon / varnish values and sludge as required by the acceptance criteria of API GL-5.

Foaming properties of lubricating compositions: ASTM D 892

This procedure is used to determine the foaming properties of a gear lubricant at 24 ° C and 93.5 ° C. Foaming is not desirable since the foam cannot adequately protect the gear or bearing surface in a car's drive train. Oil is placed in a large glass cylinder and bottom air is blown giving a porous stone. The amount of any resulting foam is measured visibly. Used oil is evaluated between sequences for trends / stability. The results of the ASTM D 892 test performed are reported in Table 8, as follows.

Table 8

 ASTM D 892 test

 Example 1 API GL-5 Requirement

 Sequence 1, ml (trend / stability)

 0/0 <20

 Sequence 2, ml (trend / stability)

 0/0 <50

 Sequence 3, ml (trend / stability)

 0/0 <20

As can be seen in Table 8 above, the lubricating composition according to the present invention passed the ASTM D 892 test by exhibiting foaming properties / foaming stability, as required by API acceptance criteria. GL-5

Corrosion property of copper in lubricating compositions: ASTM D 130

This procedure is used to determine the compatibility of a lubricant with the "yellow metal" or copper. The attack on copper, brass, bronze would be undesirable for those parts located in a transmission train of a car. A small amount of metal is placed a sample of test oil. The oil is heated in a

muffle or in an oven for 3 hours at 210 ° F (98.9 ° C). The strip is given an ASTM rating for the color change compared to a set of known standards. Candidate fluids of API GL-5 category are required to have an ASTM grade less than or equal to 3. The exemplary lubricant composition 1 passed the ASTM D 130 test by exhibiting an ASTM rating of 2e.

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Claims (3)

5 10 fifteen twenty 25 1. A lubricating composition for use in association with a device involving metal-to-metal contact of moving parts, which comprises: (a) 10-35% by weight of a low viscosity polyalphaolefin: where said polyalphaolefin has a viscosity of no more than 12 centistokes cSt) at 100 ° C. (b) 30-75% by weight of a high viscosity polyalphaolefin: wherein said high viscosity polyalphaolefin has a viscosity of 40 to 1000 centistokes cSt) at 100 ° C. (c) 5-30% by weight of a diester selected from the group consisting of di-isodecyl adipate, diisodecyl azelate and diidetridecyl adipate (d) 2-25% by weight of polyisobutylene; (e) 5-10% by weight of additive package comprising at least one additive that is effective to improve at least one lubricant property and / or performance of the equipment in which the lubricant is to be used, and, optionally (f) 0.001-0.004% by weight of an antifoaming agent; wherein the weight ratio of the low viscosity polyalphaolefin to diester is 2.6: 1 to 1: 1.6; wherein said lubricating composition meets the performance classification requirements of the American Petroleum Institute GL-5 and is classified as SAE 75W-140. 2. The lubricant composition of claim 1 wherein said lubricant composition is a multiviscous quality lubricant having a viscosity of 150,000 cP at -40 ° C and a kinematic viscosity at 100 ° C of at least 24.0 cSt and less 32.5 cSt. 3. The lubricating composition of claims 1 and / or 2, wherein said lubricating composition comprises: (a) 12-20% by weight of a low viscosity polyalphaolefin, wherein said low viscosity polyalphaolefin has a viscosity not greater than 12 centistokes cSt) at 100 ° C; (b) 40-60% by weight of a high viscosity polyalphaolefin, wherein said high viscosity polyalphaolefin has a viscosity of 40 to 1000 centistokes cSt) at 100 ° C; (c) 7.5-20% by weight of the diester; (d) 5-15% by weight of polyisobutylene; (e) 7.5-9% by weight of the additive package and, optionally (f) 0.001-0.004% by weight of the antifoaming agent.