KR20160072141A - High elastohydrodynamic shear strength fluid compositions - Google Patents

Abstract

(EHD) traction fluid without adversely affecting the ultrahydrodynamic shear strength or traction coefficient of the ultra-high shear strength annular hydrocarbon fluid in the resulting mixed fluid having improved low temperature viscosity, Dimethylsilicone fluid and / or di-alkyl or di-cycloalkyl or alkyl-cycloalkyl, or mixtures thereof, and a di-end-capped polypropylene oxide or highly branched ester and / Lubricating fluid containing cyclic hydrocarbons in combination.

Description

[0001] HIGH ELASTOHYDRODYNAMIC SHEAR STRENGTH FLUID COMPOSITIONS [0002]

The present invention relates to an ultra high shear stiffness elastohydrodynamic (EHD) traction sheave which does not adversely affect the ultrahydrodynamic shear strength or traction coefficient of the ultrahigh shear strength annular hydrocarbon fluid in the resulting mixed fluid with improved low temperature viscosity The use of a medium-viscosity dimethylsilicone fluid in combination with cyclic hydrocarbons and / or the use of di-alkyl or di-cycloalkyl or alkyl-cycloalkyl, or mixtures thereof, in order to create fluids and control the low temperature viscosity characteristics of the mixed fluid Di-end-capped polypropylene oxide or ester compound of formula (I).

An elastohydrodynamic traction drive is a nominally smooth, rolling-slip, powertrain that operates by transmitting torque through an elastohydrodynamic thin film of fluid between contacts that are subjected to high loads. The efficient transmission of the torque depends on the high stress shear strength of the fluid used to lubricate the surface at these highly stressed elastically deformed contacts. Ultra-high elastic hydrodynamic shear strength, or fluids with high traction coefficients, enables the most efficient transfer of torque from one surface to another via the contact. Thus, the shear strength characteristics of the fluid under EHD contact operating conditions effectively influence the sizing of the device for a given power or torque transfer requirement. Or EHD traction delivery of any given size determines the contact load, contact stress required to produce the required torque through the device and thus has a significant effect on the durability of the traction drive component. When the prior art fluid is a U.S. 7,645, 395 and references cited therein.

SUMMARY OF THE INVENTION

The present invention, in one embodiment, provides a lubricating fluid comprising a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 조합 in combination with a polycyclic hydrocarbon fluid. The dimethylsiloxane fluids contain 10 wt. % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

The present invention, in another embodiment, includes a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 ° F in combination with an oil-soluble die-end-capped polypropylene oxide compound and a polycyclic hydrocarbon fluid Lt; / RTI > The dimethylsiloxane fluids contain 10 wt. % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

The present invention, in another embodiment, relates to a die having a viscosity range of greater than 20 cSt at 77 조합 in combination with an ester compound independently selected from a polycyclic hydrocarbon fluid and a branched alkyl ester, cycloester, cycloalkyl ester, A methylsiloxane compound. The dimethylsiloxane fluids contain 10 wt. % ≪ / RTI > of functional groups.

Detailed Description of Specific Embodiments

The present invention provides a formulation for a high resilient hydrodynamic shear strength or traction coefficient and an excellent low temperature rheological lubricant. The combination of these properties is generally known to be very difficult to achieve in the art. Historically, fluid formulation acquisitions with excellent low temperature rheological properties have always attenuated elastic hydrodynamic shear strength to some extent. The various formulation embodiments described herein eliminate these losses and improve the elastic hydrodynamic shear strength under certain operating conditions at the elastohydrodynamic traction contact, while achieving excellent low temperature rheological properties, in which the blending scheme is indeed suitable for all- .

In one embodiment, the lubricating fluid comprises a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 ° F in combination with a polycyclic hydrocarbon fluid, wherein the dimethylsiloxane fluid has a viscosity of less than 10 wt. % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

In yet another embodiment, the lubricating fluid consists essentially of a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 조합 in combination with a polycyclic hydrocarbon fluid, wherein the dimethylsiloxane fluid comprises 10 wt. % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

In another embodiment, the lubricating fluid comprises a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 DEG F in combination with an oil-soluble, end-capped polypropylene oxide compound and a polycyclic hydrocarbon fluid, In addition to the methyl functional groups, % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

In another embodiment, the lubricating fluid is made essentially of a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 DEG F in combination with an oil-soluble, end-capped polypropylene oxide compound and a polycyclic hydrocarbon fluid, wherein the die Methyl siloxane fluids contain 10 wt. % ≪ / RTI > of functional groups, thereby altering the low temperature properties of the polycyclic hydrocarbon fluids. In one embodiment, the dimethylsiloxane fluid has a viscosity of 20 cS at 77 ° F but no greater than 50 cS.

In another embodiment, the lubricating fluid is selected from the group consisting of polycyclic hydrocarbon fluids and dimethylmethyl having a viscosity range of greater than 20 cSt at 77 DEG F in combination with an ester compound independently selected from branched alkyl esters, cycloesters, cycloalkyl esters, Siloxane compounds. The dimethylsiloxane fluids contain 10 wt. % ≪ / RTI > of functional groups.

In another embodiment, the lubricating fluid is selected from the group consisting of polycyclic hydrocarbon fluids and dimethylmethyl having a viscosity range of greater than 20 cSt at 77 DEG F in combination with an ester compound independently selected from branched alkyl esters, cycloesters, cycloalkyl esters, Lt; RTI ID = 0.0 > siloxane < / RTI > The dimethylsiloxane fluids contain 10 wt. % ≪ / RTI > of functional groups.

For the purposes of the present invention, essentially no inclusion of any component that significantly changes the low temperature properties of the polycyclic hydrocarbon fluids is excluded.

Surprisingly, it has been found that the addition of a dimethylsiloxane fluid to a polycyclic hydrocarbon fluid with or without an oil-soluble, di-end-capped polypropylene oxide compound results in a desired elasticity of the binary or ternary lubricating fluid It has been found that it produces a lubricating fluid with improved low temperature properties without deteriorating hydrodynamic shear strength properties or traction coefficient.

It has also surprisingly been found that the addition of a dimethylsiloxane fluid to a polycyclic hydrocarbon fluid comprising a branched ester, cycloester or cycloalkyl ester compound results in a desired elastic hydrodynamic It has been found that a lubricating fluid having improved low temperature properties is produced without deteriorating shear strength characteristics or traction coefficient.

Base oil

The present invention provides a lubricating fluid based on a polycyclic hydrocarbon fluid that exhibits excellent low shear strength but poor low temperature properties. In some embodiments, the polycyclic hydrocarbon fluid is a perhydrodimension of alpha-methylstyrene. In some other embodiments, the polycyclic hydrocarbon fluid is a perhydro linear dimer of alpha-methylstyrene.

In one embodiment, the polycyclic hydrocarbon fluid can be combined with a dimethylsiloxane fluid having a viscosity of at least 20 cS at 77 ° F, wherein the dimethylsiloxane fluid comprises 10 wt. % Or less of functional groups. The dimethylsiloxane fluid is 0.1 wt. To 25 wt. % ≪ / RTI >

In another embodiment, the polycyclic hydrocarbon fluid may be combined with a dimethylsiloxane fluid and an oil-soluble end-capped polypropylene oxide compound having a viscosity of at least 20 cS at 77 ° F, wherein the dimethylsiloxane fluid 10 wt. ≪ / RTI > % Or less of functional groups. The dimethylsiloxane fluid is 0.1 wt. To 25 wt. % ≪ / RTI > The oil-soluble, die-end-capped polypropylene oxide compound is 0.1 wt. To 25 wt. % ≪ / RTI > In one such embodiment, the die-end-capped polypropylene oxide compound may comprise an alkyl group, a cyclic aliphatic ring, an aromatic ring or a combination of these organic groups as the end-capping organic group. In one embodiment, the end-capping organic group has from one to ten carbon atoms.

In another embodiment, the polycyclic hydrocarbon fluid may be combined with a dimethylsiloxane fluid and a branched ester, cycloester or cycloalkyl ester compound having a viscosity of at least 20 cS at 77 ° F, wherein the dimethylsiloxane fluid 10 wt. ≪ / RTI > % Or less of functional groups. The dimethylsiloxane fluid is 0.1 wt. To 25 wt. % ≪ / RTI > The branched esters, cycloesters, cycloalkyl ester compounds and combinations thereof may be present in an amount of 0.1 wt. To 25 wt. % ≪ / RTI >

In one embodiment, the ester compound is a branched alkyl ester having 6 to 12 carbon atoms and 3 to 4 ester groups in the branched alkyl group. In one embodiment, the branched alkyl ester has at least two methyl groups distributed along the main skeleton of the branched alkyl ester. In another embodiment, the branched alkyl ester comprises at least one branched methyl or branched alkyl group per two carbon atoms located along the main skeleton of the branched alkyl ester. In one embodiment, the branched alkyl ester is trimethyl hexane trimethoxy propane ester. In yet another embodiment, the branched alkyl ester is a trimethylhexane pentaerythritol ester.

In one embodiment, the ester compound is a cycloester or cycloalkyl ester compound selected from cyclohexyl or alkylcyclohexyl groups having 6 to 10 carbon atoms and 3 to 4 ester groups. In one embodiment, the cycloester compounds independently include tri- (cyclohexyl) trimethoxypropane and tri- (cyclohexyl) pentaerythritol. In another embodiment, the cycloalkyl ester compounds independently include (alkyl branched-cyclohexyl) trimethoxy propane and tri- (alkyl branched-cyclohexyl) pentaerythritol. Examples include (methyl branch-cyclohexyl) trimethoxypropane and tri- (methylcyclohexyl) pentaerythritol. In some such embodiments, the number of methyl groups attached to the cyclohexyl group is in the range of 1-3.

In one embodiment, the dimethylsiloxane fluids may have other functional groups including, but not limited to, higher alkyl groups, cyclic aliphatic rings, aromatic rings, or combinations of these non-methyl organic groups. In another embodiment, the dimethylsiloxane fluid may be produced as a pure dimethyl-derivative.

The viscosity grade of such dimethyl siloxane fluids has the additional advantage of being relatively nonvolatile at typical lubricants or transfer operating temperatures in EHD traction drive or traction drive delivery of at least 20 cS at 77.. For example, typically 10 cSt dimethyl siloxane (at 77 ° F) has a volatility of 50 wt% at 150 ° C compared to 20 cSt dimethyl siloxane, which typically has only 5% volatility at 150 ° C .

In one embodiment, the dimethylsiloxane fluid has a viscosity of greater than 20 cSt at 77 ° F but less than 50 cS at 77 ° F .; To 25 wt. % ≪ / RTI > In one embodiment, the dimethylsiloxane fluid has a viscosity of greater than 25 cSt at 77 ° F but less than 50 cS at 77 ° F, To 25 wt. % ≪ / RTI > In one embodiment, the dimethylsiloxane fluid has a viscosity of greater than 30 cSt at 77 ° F but less than 50 cS at 77 ° F .; To 25 wt. % ≪ / RTI > In yet another embodiment, the dimethylsiloxane fluid has a viscosity of greater than 40 cSt at 77 ° F but less than 50 cS at 77 ° F .; To 25 wt. % ≪ / RTI > A higher viscosity version is considered appropriate when a higher viscosity grade elastohydrodynamic drag fluid lubricant is desired and therefore a higher formulation concentration is needed to significantly change the low temperature rheology of the finished fluid, Resulting in a finished fluid having a kinematic viscosity of about 4.0 cSt or greater.

The lubrication fluids described herein can serve as a base fluid for the mixing of high resilient hydrodynamic shear strength fluids for use in elasto-hydrodynamic continuous or infinitely variable transmissions, or for use generally in elastohydrodynamic traction drives. The combination of delivery or traction drive fluid may be completed by adding an appropriate lubricant performance additive to these combination base fluids. These additives may include antioxidants, abrasion inhibitors, corrosion inhibitors, foam inhibitors, rust inhibitors, detergents, dispersants, extreme pressure additives, friction modifiers, seal swell agents and / or viscosity modifier additives.

Various embodiments of the lubricating fluids described herein have kinematic viscosity of from about 3.7 to 4.5 cS at 100 DEG C and low temperature kinematic viscosity ranging from 28,000 cP to about 5,000 cP, which do not undermine EHD shear strength properties to any appreciable extent, Allowing the production of useful fully formulated EHD traction fluids.

The following examples illustrate various embodiments of the present invention. Other embodiments within the scope of the claims herein will be apparent to those skilled in the art from consideration of the specification or practice of the invention as set forth herein. It is intended that the specification, together with the example, be considered exemplary only, with the scope and spirit of the invention being indicated by the claims following the examples. In the examples, all percentages are given on a weight basis unless otherwise indicated.

In the following examples, the following abbreviations are used: Sep = Separation; No Sep = No separation; SCL - slightly cloudy; And Cl-

Comparative Example: A lubricating fluid comprising a perhydro-alpha-methylstyrene dimer.

Example 1: Lubricating fluid comprising perhydro-alpha-methylstyrene dimer and poly-propylene oxide.

Example 2: Lubricating fluid comprising perhydro-alpha-methylstyrene dimer, poly-propylene oxide and dimethylsiloxane, 20 cSt @ 77 F.

Example 3: Lubricating fluid comprising perhydro-alpha-methylstyrene dimer, poly-propylene oxide and dimethylsiloxane, 30 cSt @ 77 F.

Example 4: Lubricating fluid comprising perhydro-alpha-methylstyrene dimer, poly-propylene oxide and dimethylsiloxane, 50 cSt @ 77F.

Example 5: Lubricating fluid comprising a perhydro-alpha-methylstyrene dimer with or without dimethylsiloxane, with or without poly-propylene oxide, 20 cSt @ 77 ° F or 30 cSt @ 77 ° F.

Example 6: Lubricating fluid comprising perhydro-alpha-methylstyrene dimer and dimethylsiloxane, 50 cSt @ 77 F.

Example 7: Lubricating fluid containing tri-iso-C ₉ trimethoxylpropane ester with or without a dimethylsiloxane, 20 cSt @ 77 ° F.

Example 8: Lubricating fluid containing tri-iso-C ₉ pentaerythritol ester with or without a dimethylsiloxane, 20 cSt @ 77 ° F.

Those skilled in the art will appreciate that the exemplary embodiments described above may be modified without departing from the broad inventive concept thereof. It is, therefore, to be understood that the invention is not limited to the illustrated and described exemplary embodiments, but is intended to cover modifications within the spirit and scope of the invention as defined by the claims. For example, certain features of the exemplary embodiments may or may not be part of the claimed invention, and features of the disclosed embodiments may be combined. Accordingly, reference should be made to the appended claims rather than to the foregoing specification as indicating the scope of the invention. Unless specifically stated herein, the terms "a "," an ", and "the" are not to be construed as limited to a single element, but rather to the meaning "at least one.

Claims (17)

Lubricating fluid comprising:
A polycyclic hydrocarbon fluid and a dimethylsiloxane compound having a viscosity range of greater than 20 cSt at 77,, wherein the dimethylsiloxane compound is present in an amount of 0.1 wt.% Based on the lubricating fluid. % To 25 wt. %, And the dimethylsiloxane fluid is present in an amount of 10 wt. % ≪ / RTI > The composition of claim 1, wherein the polycyclic hydrocarbon fluid is a hydro hydroconjugate of alpha-methylstyrene. The composition of claim 1, wherein the polycyclic hydrocarbon fluid is a linear perhydrododimer of alpha-methylstyrene. The composition of claim 1, wherein the dimethylsiloxane compound has a viscosity of at least 20 cS at 77 ° F but no greater than 50 cS at 77 ° F. Lubricating fluid comprising:
Polycyclic hydrocarbon fluids;
0.1 wt.% Of lubricating fluid. % To 25 wt. % ≪ / RTI > by weight of the polypropylene oxide composition; And
A dimethylsiloxane compound having a viscosity range of greater than 20 cSt at 77 DEG F, wherein the dimethylsiloxane compound is present in an amount of 0.1 wt.% Based on the lubricating fluid. % To 25 wt. %, And the dimethylsiloxane fluid is present in an amount of 10 wt. % ≪ / RTI > 6. The composition of claim 5, wherein the polypropylene oxide composition corresponds to a die-end-capped polypropylene oxide of di-alkyl or di-cycloalkyl or alkyl-cycloalkyl, or mixtures thereof. 6. The composition of claim 5, wherein the polycyclic hydrocarbon fluid is a hydro hydroconjugate of alpha-methylstyrene. 8. The composition of claim 7, wherein the polycyclic hydrocarbon fluid is a linear perhydrododimer of alpha-methylstyrene. 6. The composition of claim 5, wherein the dimethylsiloxane compound has a viscosity of at least 20 cS at 77 DEG F but no greater than 50 cS at 77 DEG F. Lubricating fluid comprising:
Polycyclic hydrocarbon fluids;
An ester compound selected from the group consisting of branched alkyl esters, cycloesters, cycloalkyl esters, and combinations thereof, wherein said ester compound is present in an amount ranging from 0.1 wt% to 25 wt%; And
A dimethylsiloxane compound having a viscosity range of greater than 20 cSt at 77 DEG F, wherein the dimethylsiloxane compound is present in an amount of 0.1 wt.% Based on the lubricating fluid. % To 25 wt. %, And the dimethylsiloxane fluid is present in an amount of 10 wt. % ≪ / RTI > 11. The composition of claim 10, wherein the branched alkyl ester has from 6 to 12 carbon atoms and from 3 to 4 ester groups of the branched alkyl group. 12. The composition of claim 11, wherein the branched alkyl ester has at least two methyl groups distributed along the main skeleton of the branched alkyl ester. 13. The composition of claim 12, wherein the branched alkyl ester is trimethylhexane trimethoxypropane ester. 13. The composition of claim 12, wherein the branched alkyl ester is a trimethylhexane pentaerythritol ester. 11. The composition of claim 10, wherein the polycyclic hydrocarbon fluid is a hydro hydroconjugate of alpha-methylstyrene. 11. The composition of claim 10, wherein the polycyclic hydrocarbon fluid is a linear perhydrododimer of alpha-methylstyrene. 11. The composition of claim 10, wherein the dimethylsiloxane compound has a viscosity of at least 20 cS at 77 DEG F but less than or equal to 50 cS at 77 DEG.