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.

[0012] Accordingly, the present invention relates to a composition comprising: propylene glycol dicaprylate / dicaprate; and a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester being comprised between 55 / 45 and 90 / 10.

[0013] In the present application, unless otherwise indicated, all ranges of values used are to be understood as being inclusive limits.

[0014] In particular, the present composition comprises propylene glycol dicaprylate / dicaprate and a Guerbet ester selected from the group consisting of 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl 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.

[0015] In particular, the pour point of the composition according to the invention is lowered by at least 3°C, preferably by at least 5°C relative to the lowest pour point, e.g. the pour point of propylene glycol dicaprylate / dicaprate. Thus, the composition according to the invention can present a pour point lower than -45°C, as illustrated in Example 2.

[0016] In the present application, the pour point is measured according to the standard ASTM D97.

[0017] Moreover, propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2- octyl-1 -dodecyl isostearate may be obtained from renewable chemicals.

[0018] Advantageously, the composition according to the invention, further comprises at least an additive.

[0019] Preferably, the additive is an additive usually used in the field of lubricants.

[0020] 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.

[0021] 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.

[0022] Preferably, the antioxidant is selected from the group consisting of phenolic compounds, amines, thiadiazoles, dialkyl dithiophosphates, amine phosphates, and mixtures thereof. 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Preferably, the extreme pressure agent is selected from the group consisting of compounds based on sulphur, phosphorus and / or chlorine, and mixtures thereof.

[0031] Preferably, the total quantity of extreme pressure agent(s) represents at least 0.01 % by weight based on the weight of the composition.

[0032] 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.

[0033] Preferably, the anti-wear agent is selected from the group consisting of polysulfides, thiocarbamates, chlorinated paraffins, phosphates and thio-phosphates, and mixtures thereof.

[0034] 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. 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Preferably, the antifoam agent is selected from the group consisting of silicone oils, silicone polymers, alkyl acrylates, and mixtures thereof.

[0039] 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.

[0040] 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.

[0041] Preferably, the dispersant is selected from the group consisting of alkenylsuccinimides, succinic esters and derivatives thereof, Mannich bases, and mixtures thereof.

[0042] 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.

[0043] 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.

[0044] By “total quantity of X(s)”, it is intended to mean the quantity of all X(s) present in the composition.

[0045] An additive can have several functions.

[0046] The composition according to the invention, comprises preferably more than one additive.

[0047] 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. 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.

[0048] By “total quantity of additive(s)”, it is intended to mean the quantity of all additive(s) present in the composition.

[0049] Advantageously, the composition according to the invention, further comprises a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2- octyl-1 -dodecyl isostearate.

[0050] 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:

[0051] 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;

[0052] 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;

[0053] 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.

[0054] Group V is for all other base oils not included in any of Groups I to IV.

[0055] The base oil may be chosen among Group I -V base oils, provided it is not propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate, or 2-octyl-1 -dodecyl isostearate.

[0056] The total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate may vary from 10% to 100% by weight based on the weight of the composition.

[0057] By “total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate”, it is intended to mean the quantity of all propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate present in the composition.

[0058] Preferably, the total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl 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.

[0059] Preferably, the total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl isostearate represents at most 99.9% by weight, more preferably at most 98% by weight based on the weight of the composition.

[0060] In a first embodiment, the total quantity of propylene glycol dicaprylate / dicaprate, 2- hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate represents less than 50% by weight based on the weight of the composition.

[0061] A preferred composition of the first embodiment, comprises a total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate between 10 and 49.9% by weight; wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester being comprised between 55 / 45 and 90 / 10; weight percentages being based on the weight of the composition.

[0062] In particular, the remaining 50.1-90% by weight are one or more additive(s) and / or a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2- octyl-1 -dodecyl isostearate.

[0063] A particularly preferred composition of the first embodiment comprises or consists of:

[0064] 10-49.9% by weight of: o propylene glycol dicaprylate / dicaprate; and o a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10;

[0065] 0.1-30% by weight of one or more additive(s);

[0066] 50-89.9% by weight of a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; weight percentages being based on the weight of the composition.

[0067] In a second embodiment, the total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate represents at least 50% by weight based on the weight of the composition.

[0068] A preferred composition of the second embodiment, comprises a total quantity of propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate between 50 and 99.9% by weight; wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester being comprised between 55 / 45 and 90 / 10; weight percentages being based on the weight of the composition. In particular, the remaining 0.1-50% by weight are one or more additive(s) and / or a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2- octyl-1 -dodecyl isostearate.

[0069] A particularly preferred composition of the second embodiment comprises or consists of:

[0070] 50-99.9% by weight of: o propylene glycol dicaprylate / dicaprate; and o a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10;

[0071] 0.1-30% by weight of one or more additive(s);

[0072] 0-49.9% by weight of a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; weight percentages being based on the weight of the composition.

[0073] In a specific embodiment of this second embodiment, the composition according to the invention comprises or consists of:

[0074] 70-99.9% by weight of: o propylene glycol dicaprylate / dicaprate; and o a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10; and

[0075] 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.

[0076] In the compositions according to the invention, the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is preferably comprised between 55 / 45 and 80 / 20, more preferably between 65 / 35 and 75 / 25, such as of 70 / 30.

[0077] Preferably, the Guerbet ester is 2-hexyl-1 -decyl laurate.

[0078] In particular, the Guerbet ester is 2-hexyl-1 -decyl laurate, and the weight ratio propylene glycol dicaprylate / dicaprate / 2-hexyl-1 -decyl laurate is comprised between 65 / 35 and 80 / 20. Indeed, the pour points are then the lowest. In those conditions, the delta pour points are the greatest and are of at least -10°C. More particularly, with a weight ratio of 70 / 30, the delta pour point is of at least -15°C. 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 propylene glycol dicaprylate / dicaprate.

[0079] The present invention also relates to a process for preparing a composition according to the invention, by mixing: propylene glycol dicaprylate / dicaprate; a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; and optionally one or more additive(s) and / or a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate.

[0080] The components of the composition according to the invention can be added in any order.

[0081] Preferably, the mixing is performed at room temperature, such as between 20 and 40°C, in particular between 25 and 35°C.

[0082] 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.

[0083] By varying the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester, it is also possible to increase or decrease the kinematic viscosity of the composition and reach the desired value for a given application.

[0084] The composition according to the invention is particularly suitable to be used in the field of lubricants.

[0085] The present invention also concerns an use of the composition according to the invention, as a lubricant.

[0086] The lubricant is preferably a gear oil, a transmission fluid, or an hydraulic fluid.

[0087] 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.

[0088] The device(s) may be a gear or a transmission, in particular the device(s) is / are in an electric vehicle.

[0089] The present invention also concerns an use of the composition according to the invention, as a liquid dielectric coolant.

[0090] 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. 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.

[0091] 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.

[0092] Preferably, the device(s) is a gear, an electric motor, a transmission, a battery, and / or the power electronics of an electric vehicle.

[0093] The combination of propylene glycol dicaprylate / dicaprate and a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate, having a pour point of -45°C or lower, allows to lower the pour point of a base oil, when mixed with said base oil.

[0094] The present invention also relates to an use of 2 propylene glycol dicaprylate / dicaprate and a Guerbet ester selected from the group consisting of 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl isostearate, wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10, to lower the pour point of a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate.

[0095] Thus, the present invention also concerns a method for lowering the pour point of a base oil other propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1- dodecyl isostearate, comprising mixing said base oil with propylene glycol dicaprylate / dicaprate and a Guerbet ester selected from the group consisting of 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl isostearate, wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10.

[0096] The propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate, 2-octyl-1- dodecyl isostearate and the base oil, are as described above, including preferential features and embodiments.

[0097] Preferably, the pour point of the base oil is higher than the pour point of the combination of propylene glycol dicaprylate / dicaprate and Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate. In particular, the pour point of the base oil is of -45°C or higher.

[0098] In particular, the weight ratio propylene glycol dicaprylate / dicaprate / 2-hexyl-1 -decyl laurate is comprised between 65 / 35 and 80 / 20, preferably 70 / 30. Indeed, with such weight ratio, the pour point of the combination of propylene glycol dicaprylate / dicaprate and, 2- hexyl-1-decyl laurate or 2-octyl-1 -dodecyl isostearate, is significantly lowered, such as of at least -10°C, making it possible to better lower the pour point of the composition according to the invention comprising a base oil other than propylene glycol dicaprylate / dicaprate, 2- hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate. More particularly, the pour point is lower when the Guerbet ester is 2-hexyl-1 -decyl laurate.

[0099] The resulting pour point of the composition according to the invention is lower than the pour point of the base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1- decyl laurate and 2-octyl-1 -dodecyl isostearate.

[0100] The invention is further described in the following examples, given by way of illustration.

[0101] Example 1 : Compositions according to the invention and comparative compositions

[0102] 1.1. Chemicals used propylene glycol dicaprylate / dicaprate: Radia 7208 from Oleon;

[0103] 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);

[0104] 2-octyl-1 -dodecyl isostearate: was prepared by esterification of 2-octyl-1- dodecanol (Isofol 20 from Sasol) with isostearic acid (Radiacid 0905 from Oleon);

[0105] 1.2. Preparation of the compositions according to the invention

[0106] The compositions C1-C5 were prepared by mixing propylene glycol dicaprylate / dicaprate with 2-hexyl-1 -decyl laurate or 2-octyl-1 -dodecyl isostearate, at room temperature (25°C) according to quantities described in Table 1.

[0107] 1.3. Preparation of the comparative composition

[0108] The comparative composition CC1 was prepared by mixing 40% by weight of propylene glycol dicaprylate / dicaprate with 60% by weight of 2-hexyl-1 -decyl laurate at room temperature (25°C).

[0109] Example 2: Pour point of the compositions

[0110] Pour points were measured for each ester and composition according to the standard ASTM D97.

[0111] The pour point of propylene glycol dicaprylate / dicaprate is of -41 °C.

[0112] The pour point of 2-hexyl-1 -decyl laurate was of -32°C.

[0113] The pour point of 2-octyl-1 -dodecyl isostearate was of -33°C.

[0114] Each delta pour point was calculated relative to the lowest pour point of the esters among propylene glycol dicaprylate / dicaprate and the Guerbet ester in the corresponding composition, e.g. the pour point of propylene glycol dicaprylate / dicaprate.

[0115] Results are gathered in Table 1.

[0116] Compositions C1 -C5 present all a pour point lower than the lowest pour of propylene glycol dicaprylate / dicaprate (-41°C). With weight ratio propylene glycol dicaprylate / dicaprate I 2-hexyl-1 -decyl laurate of 70 / 30 (C2), the delta pour point is the greatest with a value of -18°C. Thus, composition C2 according to the invention reaches a pour point lower than -55°C.

[0117] On the opposite, comparative composition CC1 with a weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester out of the range 55 / 45 and 90 / 10, does not present a pour point lower than the lowest pour point of the esters contained in the comparative composition, e.g. the pour point of propylene glycol dicaprylate / dicaprate that is of -41 °C. The pour point of CC1 is of -39°C, comprised between the highest (-32°C) and the lowest (-41 °C) pour points of the chemicals contained in the corresponding comparative composition, as usually expected.

Claims

Claims1. Composition comprising: propylene glycol dicaprylate / dicaprate; and a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester being comprised between 55 / 45 and 90 / 10.

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

3. Composition according to claim 1 to 2, further comprising a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1- dodecyl isostearate.

4. Process for preparing a composition according to any of claims 1 to 3, by mixing: propylene glycol dicaprylate / dicaprate; a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate; and optionally one or more additive(s) and / or a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl 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 propylene glycol dicaprylate / dicaprate and a Guerbet ester selected from the group consisting of 2-hexyl-1 -decyl laurate and 2-octyl-1 -dodecyl isostearate, wherein the weight ratio propylene glycol dicaprylate / dicaprate I Guerbet ester is comprised between 55 / 45 and 90 / 10, to lower the pour point of a base oil other than propylene glycol dicaprylate / dicaprate, 2-hexyl-1 -decyl laurate and 2-octyl-1- dodecyl isostearate.

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