Low pour point fatty ester compositions

Abstract

The present invention relates to a composition comprising specific esters and its uses as a lubricant and / or a liquid dielectric coolant.

Description

[0001] LOW POUR POINT FATTY ESTER COMPOSITIONS

[0002] The present invention relates to a composition comprising specific esters and its uses as a lubricant and / or a liquid dielectric coolant.

[0003] The specific combination of esters of the composition presents an unexpected low pour point. Indeed, usually when two chemicals are mixed, the pour point of the mixture is comprised between the pour point of each separate chemical. In the present invention, the pour point of the combination of esters is lower than the lowest pour point of the two esters.

[0004] The pour point of a fluid is the lowest temperature at which the fluid flows. Also, this characteristic is critical for applications in very cold environments.

[0005] For instance, for outdoor applications, lubricants still need to be liquid and pumpable at low temperature, such as at a temperature of at least -30°C. For applications in extreme environments, lubricants still need to be liquid and pumpable at even lower temperatures, such as at a temperature of at least -45°C.

[0006] A lubricant typically comprises a base oil, usually the major constituent (the constituent whose content is the highest), and one or more additive(s). An additive is used to enhance one or more intrinsic property(ies) of the base oil and I or to provide it with one or more additional property(ies).

[0007] Since base oils do not necessarily have a sufficiently low pour point, a pour point depressant is added as additive to base oils to lower the pour point.

[0008] Usual pour point depressants are polymers, such as polyalkylmethacrylates, polymethacrylates, polyacrylates, acrylate-styrene copolymers, esterified olefin- or styrene maleic anhydride copolymers, alkylated polystyrenes, and vinyl acetate-fumarate copolymers.

[0009] Those pour point depressants are not biodegradable and not obtained from renewable chemicals. Additionally, they are often developed for mineral base oils and have a limited impact on ester base oils, which are yet more and more developed as sustainable solutions.

[0010] Also, there is still a need for a sustainable ester base oil that would have a pour point lower than -45°C.

[0011] The Applicant surprisingly found that a specific combination of esters presents an improved pour point and even one or more additional advantage(s).

[0012] Accordingly, the present invention relates to a composition comprising:

[0013] 2-hexyl-1 -decyl heptanoate; and

[0014] 2-hexyl-1 -decyl isostearate; wherein the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10.

[0015] In the present application, unless otherwise indicated, all ranges of values used are to be understood as being inclusive limits.

[0016] In particular, the present composition comprises 2-hexyl-1 -decyl heptanoate and 2- hexyl-1 -decyl isostearate, which in combination, present a pour point lower than the pour point of each of them separately. Consequently, the composition of the invention presents an unexpected low pour point.

[0017] In particular, the pour point of the composition according to the invention is lowered by at least 5°C, preferably by at least 10°C relative to the lowest pour point, e.g. the pour point of 2-hexyl-1 -decyl heptanoate. Thus, the composition according to the invention can present a pour point lower than -60°C, preferably lower than -65°C, such as of -70°C or lower, as illustrated in Example 2.

[0018] In the present application, the pour point is measured according to the standard ASTM D97.

[0019] Moreover, 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate may be obtained from renewable chemicals.

[0020] Advantageously, the composition according to the invention, further comprises at least an additive.

[0021] Preferably, the additive is an additive usually used in the field of lubricants.

[0022] The additive(s) used in the field of lubricants, may be easily selected by a person skilled in the art who knows how to select the most suitable additive(s) and its / their quantity(ies) depending on the application. By way of example, reference may be made to the following manuals: “Fuels and Lubricants Handbook : technology, properties performance and testing”, by George E. Totten, 2003 and “Handbook of lubrification and tribology, vol II : Theory and Design”, by Robert W. Bruce, 2012.

[0023] The at least an additive used in the field of lubricants is preferably selected from the group consisting of antioxidants, corrosion inhibitors, metal deactivators, extreme pressure agents, anti-wear agents, friction modifiers, antifoam agents, dispersants, and mixtures thereof.

[0024] Preferably, the antioxidant is selected from the group consisting of phenolic compounds, amines, thiadiazoles, dialkyl dithiophosphates, amine phosphates, and mixtures thereof.

[0025] Preferably, the total quantity of antioxidant(s) represents at least 0.01%, more preferably at least 0.05%, even more preferably at least 0.1 % by weight based on the weight of the composition. Preferably, the total quantity of antioxidant(s) represents at most 5%, more preferably at most 3%, even more preferably at most 1 .5% by weight based on the weight of the composition.

[0026] Preferably, the corrosion inhibitor is selected from the group consisting of alkali metal and / or alkaline earth metal sulphonates (Na, Mg, Ca salts), fatty acids, fatty amines, alkenylsuccinic acids and / or their derivatives, benzotriazole, tolyltriazole, and mixtures thereof.

[0027] Preferably, the total quantity of corrosion inhibitor(s) represents at least 0.01 %, more preferably at least 0.05%, even more preferably at least 0.1 % by weight based on the weight of the composition.

[0028] Preferably, the total quantity of corrosion inhibitor(s) represents at most 5 %, more preferably at most 3%, even more preferably at most 1 .5% by weight based on the weight of the composition.

[0029] Preferably, the metal deactivator is selected from the group consisting of heterocyclic compounds containing nitrogen and / or sulphur, such as triazole, tolyltriazole, benzotriazole, and mixtures thereof.

[0030] Preferably, the total quantity of metal deactivator(s) represents at least 0.001%, more preferably at least 0.01% by weight based on the weight of the composition.

[0031] Preferably, the total quantity of metal deactivator(s) represents at most 0.050%, more preferably at most 0.025% by weight based on the weight of the composition.

[0032] Preferably, the extreme pressure agent is selected from the group consisting of compounds based on sulphur, phosphorus and / or chlorine, and mixtures thereof.

[0033] Preferably, the total quantity of extreme pressure agent(s) represents at least 0.01 % by weight based on the weight of the composition.

[0034] Preferably, the total quantity of extreme pressure agent(s) represents at most 5 %, more preferably at most 1 .5%, even more preferably at most 0.2% by weight based on the weight of the composition.

[0035] Preferably, the anti-wear agent is selected from the group consisting of polysulfides, thiocarbamates, chlorinated paraffins, phosphates and thio-phosphates, and mixtures thereof.

[0036] Preferably, the total quantity of anti-wear agent(s) represents at least 0.01%, more preferably at least 0.1 %, even more preferably at least 0.2% by weight based on the weight of the composition.

[0037] Preferably, the total quantity of anti-wear agent(s) represents at most 5%, more preferably at most 4% by weight based on the weight of the composition. Preferably, the friction modifier is selected from the group consisting of partial esters of fatty acids and polyhydroxy alcohols such as glycerol mono oleate (GMO), fatty amides such as oleate diethanolamide (ODEA), and mixtures thereof.

[0038] Preferably, the total quantity of friction modifier(s) represents at least 0.01 %, more preferably at least 0.05%, even more preferably at least 0.1 % by weight based on the weight of the composition.

[0039] Preferably, the total quantity of friction modifier(s) represents at most 5%, more preferably at most 2.5%, even more preferably at most 1 % by weight based on the weight of the composition.

[0040] Preferably, the antifoam agent is selected from the group consisting of silicone oils, silicone polymers, alkyl acrylates, and mixtures thereof.

[0041] Preferably, the total quantity of antifoam agent(s) represents at least 0.01%, more preferably at least 0.1 %, even more preferably at least 0.5% by weight based on the weight of the composition.

[0042] Preferably, the total quantity of antifoam agent(s) represents at most 5%, more preferably at most 3%, even more preferably at most 1.5% by weight based on the weight of the composition.

[0043] Preferably, the dispersant is selected from the group consisting of alkenylsuccinimides, succinic esters and derivatives thereof, Mannich bases, and mixtures thereof.

[0044] Preferably, the total quantity of dispersant(s) represents at least 0.01%, more preferably at least 0.1 %, even more preferably at least 0.5% by weight based on the weight of the composition.

[0045] Preferably, the total quantity of dispersant(s) represents at most 15%, more preferably at most 10%, even more preferably at most 5% by weight based on the weight of the composition.

[0046] By “total quantity of X(s)”, it is intended to mean the quantity of all X(s) present in the composition.

[0047] An additive can have several functions.

[0048] The composition according to the invention, comprises preferably more than one additive.

[0049] The total quantity of additive(s) is preferably of at least 0.1%, more preferably of at least 0.3%, even more preferably of at least 2% by weight based on the weight of the composition.

[0050] The total quantity of additive(s) is preferably of at most 30%, more preferably of at most 25%, even more preferably of at most 20% by weight based on the weight of the composition. By “total quantity of additive(s)”, it is intended to mean the quantity of all additive(s) present in the composition.

[0051] Advantageously, the composition according to the invention, further comprises a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0052] The American Petroleum Institute (API) has categorized base oils into five groups: Group l-lll base oils are mineral oils refined from petroleum crude oil:

[0053] Group I base oils have a saturated hydrocarbon content of less than 90 % by weight, an aromatic hydrocarbon content of more than 1 .7 % by weight, a sulphur content of more than 0.03 % by weight, and a viscosity index between 80 and 120;

[0054] Group II base oils have a saturated hydrocarbon content of more than 90 % by weight, an aromatic hydrocarbon content of less than 1 .7 % by weight, a sulphur content of less than 0.03 % by weight, and a viscosity index between 80 and 120;

[0055] Group III base oils have a saturated hydrocarbon content of more than 90 % by weight, an aromatic hydrocarbon content of less than 1 .7 % by weight, a sulphur content of less than 0.03 % by weight, and a viscosity index greater than 120; the percentages by weight being based on the weight of the base oil. Group IV base oils are synthetic oils, such as polyalphaolefins.

[0056] Group V is for all other base oils not included in any of Groups I to IV.

[0057] The base oil may be chosen among Group I -V base oils, as long as it is neither 2- hexyl-1-decyl heptanoate nor 2-hexyl-1 -decyl isostearate.

[0058] The total quantity of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate may vary from 10% to 100% by weight based on the weight of the composition.

[0059] By “total quantity of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate”, it is intended to mean the quantity of both 2-hexyl-1 -decyl laurate and 2-hexyl-1 -decyl heptanoate present in the composition.

[0060] Preferably, the total quantity of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate represents at least 10%, more preferably at least 15%, even more preferably at least 20% by weight, such as 25% and 30% by weight, based on the weight of the composition.

[0061] Preferably, the total quantity of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate represents at most 99.9% by weight, more preferably at most 98% by weight based on the weight of the composition. In a first embodiment, the total quantity of 2-hexyl-1 -decyl heptanoate and 2-hexyl- 1 -decyl isostearate represents less than 50% by weight based on the weight of the composition.

[0062] A preferred composition of the first embodiment, comprises a total quantity of 2- hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate between 10 and 49.9% by weight; wherein the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10; weight percentages being based on the weight of the composition.

[0063] In particular, the remaining 50.1-90% by weight are one or more additive(s) and / or a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0064] A particularly preferred composition of the first embodiment comprises or consists of:

[0065] 10-49.9% by weight of: o 2-hexyl-1 -decyl heptanoate; and o 2-hexyl-1 -decyl isostearate; wherein the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10; and

[0066] 0.1-30% by weight of one or more additive(s); weight percentages being based on the weight of the composition.

[0067] 50-89.9% by weight of a base oil other than 2-hexyl-1 -decyl heptanoate and 2- hexyl-1 -decyl isostearate; weight percentages being based on the weight of the composition.

[0068] In a second embodiment, the total quantity of 2-hexyl-1 -decyl heptanoate and 2- hexyl-1 -decyl isostearate represents at least 50% by weight based on the weight of the composition.

[0069] A preferred composition of the second embodiment, comprises a total quantity of 2- hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate between 50 and 99.9% by weight; wherein the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10; weight percentages being based on the weight of the composition.

[0070] In particular, the remaining 0.1-50% by weight are one or more additive(s) and / or a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0071] A particularly preferred composition of the second embodiment comprises or consists of:

[0072] 50-99.9% by weight of: o 2-hexyl-1 -decyl heptanoate; and o 2-hexyl-1 -decyl isostearate; wherein the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10;

[0073] 0.1-30% by weight of one or more additive(s);

[0074] 0-49.9% by weight of a base oil other than 2-hexyl-1 -decyl heptanoate and 2- hexyl-1 -decyl isostearate; weight percentages being based on the weight of the composition.

[0075] In a specific embodiment of this second embodiment, the composition according to the invention comprises or consists of:

[0076] 70-99.9% by weight of: o 2-hexyl-1 -decyl heptanoate; and o 2-hexyl-1 -decyl isostearate; wherein the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10; and

[0077] 0.1-30% by weight of one or more additive(s) used in the field of lubricants; weight percentages being based on the weight of the composition.

[0078] In the compositions according to the invention, the weight ratio 2-hexyl-1 -decyl heptanoate / 2-hexyl-1 -decyl isostearate is preferably comprised between15 / 85 and 85 / 15, more preferably between 20 / 80 and 80 / 20, such as between 30 / 70 and 80 / 20, and between 40 / 60 and 80 / 20.

[0079] In particular, the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 60 / 40 and 80 / 20. Indeed, when the weight ratio 2-hexyl- 1 -decyl heptanoate 1 2-hexyl-1 -decyl isostearate is comprised in this range, the delta pour point is the greatest, preferably of -20°C or lower.

[0080] The delta pour point is the difference between the pour point of the composition and the lowest pour point of the chemicals present in the composition, e.g. in the present case, the pour point of 2-hexyl-1 -decyl heptanoate.

[0081] The present invention also relates to a process for preparing a composition according to the invention, by mixing 2-hexyl-1 -decyl heptanoate;

[0082] 2-hexyl-1 -decyl isostearate; and optionally one or more additive(s) and / or a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0083] The components of the composition according to the invention can be added in any order.

[0084] Preferably, the mixing is performed at room temperature, such as between 20 and 40°C, in particular between 25 and 35°C. As illustrated in Example 2, the pour point of the composition according to the invention may vary depending on the weight ratio between the esters contained in the composition.

[0085] By varying the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1 -decyl isostearate, it is also possible to increase or decrease the kinematic viscosity of the composition and reach the desired value for a given application.

[0086] The composition according to the invention exhibits good properties, such as elastomer compatibility and lubricity properties.

[0087] The composition according to the invention presents particularly good compatibility with NBR and FKM elastomer types.

[0088] By “good compatibility with elastomer(s)”, it is intended to mean that after immersion of an elastomer in the composition according to the invention, for 168 hours at 100°C, the elastomer presents no more than 20%, preferably no more than 15% change in volume.

[0089] As shown in Example 3.2, the volume change of those elastomers is limited (less than 15%) when immersed in a composition according to the invention.

[0090] The traction coefficient of the composition according to the invention is lower than the traction coefficient of a Group III base oil, as shown in Example 3.3 and illustrated by Fig 1.

[0091] With all those improved properties, the composition according to the invention is particularly suitable to be used in the field of lubricants.

[0092] The present invention also concerns an use of the composition according to the invention, as a lubricant.

[0093] The lubricant is preferably a gear oil, a transmission fluid, or an hydraulic fluid.

[0094] In other words, the present invention concerns a method for lubricating one or more device(s), by bringing into contact the device(s) with the composition according to the invention.

[0095] The device(s) may be a gear or a transmission, in particular the device(s) is / are in an electric vehicle.

[0096] The present invention also concerns an use of the composition according to the invention, as a liquid dielectric coolant.

[0097] Preferably, the liquid dielectric coolant is used as an electrical insulation and cooling medium for electrical device(s), such as transformers, servers, switches, rectifiers, cables, and capacitors.

[0098] The present invention concerns thus a method for lubricating and / or cooling one or more device(s), by bringing into contact the device(s) with the composition according to the invention. In a particular embodiment, the composition according to the invention may be used to lubricate and to cool device(s) present in an electric vehicle.

[0099] Preferably, the device(s) is a gear, an electric motor, a transmission, a battery, and / or the power electronics of an electric vehicle.

[0100] The combination of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate having a pour point of -60°C or lower, allows to lower the pour point of a base oil, when mixed with said base oil.

[0101] The present invention also concerns an use of 2-hexyl-1 -decyl heptanoate and 2- hexyl-1 -decyl isostearate, wherein the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1- decyl isostearate is comprised between 10 / 90 and 90 / 10, to lower the pour point of a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0102] Thus, the present invention also concerns a method for lowering the pour point of a base oil, comprising mixing said base oil with 2-hexyl-1 -decyl heptanoate and 2-hexyl-1- decyl isostearate wherein the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10.

[0103] The 2-hexyl-1 -decyl heptanoate, 2-hexyl-1 -decyl isostearate and the base oil, are as described above, including preferential features and embodiments.

[0104] Preferably, the pour point of the base oil is higher than the pour point of the combination 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate. In particular, the pour point of the base oil is of -60°C or higher.

[0105] Preferably, the weight ratio 2-hexyl-1 -decyl heptanoate / 2-hexyl-1 -decyl isostearate is comprised between 60 / 40 and 80 / 20. Indeed, with this specific wight ratio, the pour point of the combination 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate is significantly lowered, such as of at least -20°C, making it possible to better lower the pour point of the composition according to the invention comprising a base oil other than 2-hexyl- 1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

[0106] The invention is further described in the following examples, given by way of illustration, with reference to the Figure 1 representing a graph relating to the evolution of the traction coefficients of composition 1 according to the invention and of a mineral oil from Group III base oil, according to the slide roll ratio applied.

[0107] Example 1 : Compositions according to the invention and comparative compositions

[0108] 1.1. Chemicals used

[0109] 2-hexyl-1 -decyl heptanoate: was prepared by esterification of 2-hexyl-1- decanol (Isofol 16 from Sasol) with heptanoic acid (Oleris n-heptanoic acid from Arkema); 2-hexyl-1 -decyl isostearate: was prepared by esterification of 2-hexyl-1 -decanol (Isofol 16 from Sasol) with isostearic acid (Radiacid 0905 from Oleon);

[0110] 2-ethyl-1 -hexyl isostearate: was prepared by esterification of 2-ethyl-1 -hexanol (from Perstorp) with isostearic acid (Radiacid 0905 from Oleon);

[0111] 2-hexyl-1 -decyl laurate: was prepared by esterification of 2-hexyl-1 -decanol (Isofol 16 from Sasol) with lauric acid (Radiacid 0653 from Oleon).

[0112] 1.2. Preparation of compositions according to the invention

[0113] The compositions C1 -C3 were prepared by mixing 2-hexyl-1 -decyl heptanoate with 2-hexyl-1 -decyl isostearate at room temperature (25°C) according to quantities described in Table 1.

[0114] 1.3. Preparation of comparative compositions

[0115] The comparative composition CC1 was prepared by mixing 60 wt% of 2-hexyl-1- decyl heptanoate with 40 wt% of 2-ethyl-1 -hexyl isostearate at room temperature (25°C).

[0116] The comparative composition CC2 was prepared by mixing 40 wt% of 2-hexyl-1- decyl heptanoate with 60 wt% of 2-hexyl-1 -decyl laurate at room temperature (25°C).

[0117] Example 2: Pour point of the compositions

[0118] Pour points were measured for each ester and composition according to standard ASTM D97.

[0119] The pour point of 2-hexyl-1 -decyl heptanoate was of -57°C.

[0120] The pour point of 2-hexyl-1 -decyl isostearate was of -48°C.

[0121] The pour point of 2-ethyl-1 -hexyl isostearate was of -32°C.

[0122] The pour point of 2-hexyl-1 -decyl laurate was of -32°C.

[0123] Each delta pour point was calculated relative to the lowest pour point of the esters, e.g. -57°C, contained in the corresponding composition.

[0124] Results for compositions are gathered in Tables 1 and 2.

[0125] Table 1 : Compositions C1-C3 according to the invention and their pour points

[0126] Table 2: Comparative compositions CC1-CC2 and their pour points

[0127] Compositions C1-C3 present all a delta pour point of at least -10°C. With weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate of 60 / 40 or 80 / 20, the delta pour points are even greater with values of at least -20°C. Indeed, compositions C1 and C2 according to the invention reached each a pour point lower than -75°C.

[0128] On the opposite, comparative compositions CC1 and CC2 comprising other esters, respectively 2-ethyl-1 -hexyl isostearate and 2-hexyl-1 -decyl laurate instead of 2-hexyl-1- decyl isostearate, do not present a pour point lower than the lowest pour point of the esters contained in the comparative compositions, e.g. the pour point of 2-hexyl-1 -decyl heptanoate that is of -57°C. With respectively -50°C and -43°C, the pour points of the comparative compositions are comprised between the highest (-32°C) and the lowest (- 57°C) pour point of the chemicals of the comparative compositions, as usually expected.

[0129] Example 3: Other characteristics of the composition according to the invention

[0130] 3.1 Kinematic viscosity

[0131] The kinematic viscosity at 40°C (KV 40) was measured according to the standard ASTM D445.

[0132] The kinematic viscosity of a diester (di-2-ethylhexyl succinate, Radia 7545 from Oleon) with a similar pour point that the composition 1 (-77°C) was also measured.

[0133] Results are gathered in Table 3.

[0134] 3.2 Elastomer compatibility

[0135] The compatibility of the composition according to the invention with elastomers was measured according to the standard ISO 6072 by immersing each elastomer in a composition for 168 hours at 100°C.

[0136] The percentages of volume change of each elastomer after immersion in a composition are gathered in Table 3.

[0137] Table 3: Characteristics of Composition 1 according to the invention and of a diester

[0138] The composition C1 according to the invention presents a good compatibility with elastomers. In particular, it was observed less than 15% change in volume with elastomer NBR 1 , and less than 2.5% change in volume with elastomer FKM 2, when those elastomers were immersed in the composition C1.

[0139] On the opposite, the diester, while having a low pour point and a kinematic viscosity close to the kinematic viscosity of composition C1 , has a poor compatibility with elastomers, particularly NBR1.

[0140] Also, the compositions according to the invention appear to be a good alternative to diesters for a given pour point and kinematic viscosity, in terms of elastomer compatibility.

[0141] 3.3 Lubricity property

[0142] The lubricity of a fluid is its ability to reduce friction (friction or deformation between moving parts) and / or to reduce wear on parts.

[0143] Therefore, the lubricity property of the composition according to the invention was evaluated by measuring the friction reduction using a Mini Traction Machine (MTM) device under the following conditions:

[0144] Material : steel ball on steel disc

[0145] Load : 50N

[0146] Temperature : 40°C

[0147] Rolling speed : 1000 mm / s

[0148] Slide Roll Ratio: from 0 to 70%.

[0149] For reference, a mineral oil from Group III base oil (Nexbase 3043 from Neste), generally used in compressor, gear and hydraulic fluids, was also evaluated under same conditions.

[0150] The curves obtained are represented in Fig.1.

[0151] It can be observed in Fig. 1 , that the traction coefficient curve of the composition C1 according to the invention is lower than the traction coefficient curve of the mineral oil.

[0152] This confirm that the composition according to the invention has a good lubricity property, and can therefore be used as a lubricant.

Claims

Claims1. Composition comprising:2-hexyl-1 -decyl heptanoate; and2-hexyl-1 -decyl isostearate; wherein the weight ratio 2-hexyl-1 -decyl heptanoate 12-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10.

2. Composition according to claim 1 , further comprising at least an additive.

3. Composition according to any of claims 1 to 2, further comprising a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

4. Process for preparing a composition according to any of claims 1 to 3, by mixing2-hexyl-1 -decyl heptanoate;2-hexyl-1 -decyl isostearate; and optionally one or more additive(s) and / or a base oil other than 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate.

5. Use of the composition according to any of claims 1 to 3, as a lubricant.

6. Use of the composition according to any of claims 1 to 3, as a liquid dielectric coolant.

7. Use of 2-hexyl-1 -decyl heptanoate and 2-hexyl-1 -decyl isostearate, wherein the weight ratio 2-hexyl-1 -decyl heptanoate I 2-hexyl-1 -decyl isostearate is comprised between 10 / 90 and 90 / 10, to lower the pour point of a base oil other than 2-hexyl-1- decyl heptanoate and 2-hexyl-1 -decyl isostearate.

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