Diester-based lubricating composition

Abstract

The invention relates to a lubricating composition comprising: one or more diesters, each of which is formed between:-a diol selected from the group consisting of 1, 2-propanediol, 1, 2-decanediol and 1, 3-diols having from 3 to 10 carbon atoms, and-two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising from 4 to 10 carbon atoms; and at least one base oil different from the diester and / or at least one additive different from the diester selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index improvers (VI), pour point depressants (PPD), dispersants, antifoams, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

Description

Technical Field

[0001] The present invention relates to the field of compositions for lubricating and / or cooling parts of mobile or stationary systems (such as heavy or light vehicles, public works vehicles or energy storage devices). The present invention more specifically relates to the use of novel compounds such as diesters in cooling and / or lubricating compositions, especially in heavy or light vehicles, public works machinery, or energy storage devices. Background Art

[0002] Lubricating compositions, also called "lubricants", are generally used in different components of motor vehicles, with the main purpose of reducing the friction between the different metal parts moving in the components, more particularly the engine, the transmission and the hydraulic circuit. In addition, the lubricating composition is effective in preventing premature wear and even damage to these components, in particular to their surfaces. For this purpose, lubricating compositions generally consist of a base oil, which is usually associated with a variety of additives specifically intended to stimulate the lubricating properties of the base oil, such as friction modifiers, but also to obtain additional properties.

[0003] Lubricating compositions for transmissions, such as transmissions or axles, must meet numerous requirements, in particular with regard to the stringent specifications imposed by automobile manufacturers. More particularly, the lubricating composition must have satisfactory properties in terms of viscosity, viscosity-temperature resistance, low temperature performance, etc., which are suitable for its implementation in a transmission member of a vehicle, in particular in a transmission or axle.

[0004] Lubricating compositions, also known as cooling compositions, may also be used in energy storage devices such as data centers.

[0005] There is a need to provide lubricating and / or cooling compositions of renewable plant origin that have less impact on the environment.

[0006] Furthermore, current environmental problems, especially those aimed at reducing carbon dioxide emissions, necessitate a reduction in the fuel consumption of motor vehicles. It is therefore well known that lubricating compositions are an effective means of acting on fuel consumption through their influence on the friction generated between the different components of motor vehicles. It is therefore desirable to develop lubricants that reduce the friction of transmissions and axle differentials.

[0007] Improving the "fuel economy" properties of transmission lubricants, while maintaining the required high performance levels, remains a challenge.

[0008] As an example of a transmission lubricant, the document WO 2010 / 038147 can be mentioned, which proposes that, in order to save fuel, at least 30% by weight of one or more fatty acid methyl esters of the formula RCOOCH3 (wherein R is a paraffin or olefin moiety having 11 to 23 carbon atoms) is used in combination with one or more phosphorus, sulfur or phosphorus-sulfur antiwear agents and / or extreme pressure agents and polyalphaolefins to formulate a lubricating composition for a transmission.

[0009] Mention may also be made of document US 2017 / 0145337, which describes a lubricating composition for transmissions based on a kinematic viscosity of 1.5 mm at 100° C. 2 / s to 3.5mm 2 / s range, showing a gain in "fuel economy", the base oil comprising 3% to 10% of a 2 mm kinematic viscosity at 100°C 2 / s to 10mm 2 / s range of monoester type oils, and ester type oils providing sulfur.

[0010] The present invention aims to propose a novel lubricating composition having improved properties with regard to friction reduction or cooling properties.

[0011] The present invention also aims to propose a novel lubricating composition which exhibits improved properties in terms of fuel economy (“Fuel Eco” properties) while satisfying the properties required for its use in lubricating transmission components (such as transmissions and axles) of light or heavy motor vehicles, more particularly, exhibiting good performance in terms of low temperature properties. Summary of the invention

[0012] Therefore, the subject matter of the present invention mainly relates to a lubricating composition comprising:

[0013] - one or more diesters, each of which is formed between:

[0014] o a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0015] o two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms; and

[0016] at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

[0017] According to one embodiment, the lubricating composition according to the invention comprises, relative to the total weight of the lubricating composition:

[0018] 5 to 95% by weight, preferably 10 to 90% by weight, further preferably 20 to 80% by weight, even more preferably 30 to 70% by weight or even 40 to 60% by weight of the one or more diesters,

[0019] 1% to 95% by weight, preferably 10% to 90% by weight, more preferably 20% to 80% by weight, further more preferably 30% to 70% by weight or even 40% to 60% by weight of one or more base oils different from the diesters,

[0020] - Optionally, 0.01 to 20% by weight, preferably 0.05 to 15% by weight, further preferably 0.1 to 10% by weight, further more preferably 0.5 to 7% by weight or even 1 to 5% by weight of one or more additives other than diesters and other than the base oil or oils.

[0021] According to one embodiment, the lubricating composition according to the invention comprises, relative to the total weight of the lubricating composition:

[0022] at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, preferably at least 50% by weight, more preferably at least 70% by weight or even at least 90% by weight of one or more diesters;

[0023] 0.01 to 20 wt. %, preferably 0.05 to 15 wt. %, more preferably 0.1 to 10 wt. %, still more preferably 0.5 to 7 wt. % or even 1 to 5 wt. % of one or more additives selected from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper thickeners and mixtures thereof; and

[0024] - Optionally, 5 to 94% by weight, preferably 10 to 94% by weight, preferably 15 to 90% by weight, of one or more base oils different from the diesters according to the invention.

[0025] Preferably, the diester comprises 13 to 25 carbon atoms; preferably the diester comprises 13 to 24 carbon atoms.

[0026] Preferably, the kinematic viscosity of the diester at 100°C is 1 mm 2 / s to 6mm 2 / s range, preferably within 1mm 2 / s to 4mm 2 / s range.

[0027] Preferably, the diol is selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-alkanediol having 3 to 7 carbon atoms, preferably the diol is selected from 1,2-propylene glycol and 1,3-propylene glycol, and more preferably, the diol is 1,2-propylene glycol.

[0028] Preferably, the monocarboxylic acids, which may be the same or different, comprise a linear hydrocarbon chain having from 4 to 10 carbon atoms, preferably from 5 to 9 carbon atoms.

[0029] Preferably, the one or more diesters are selected from:

[0030] — diester formed from 1,2-decanediol and two heptanoic acids,

[0031] — diesters formed from 1,2-decanediol and two valeric acids,

[0032] - a diester formed from 1,2-propylene glycol and two heptanoic acids,

[0033] — diesters formed from 1,2-propylene glycol and two nonanoic acids,

[0034] - a diester formed from 1,3-propanediol and two heptanoic acids,

[0035] — a diester formed from 1,2-propylene glycol and two octanoic acids,

[0036] - a diester formed from 1,2-propylene glycol and two capric acids,

[0037] - a diester formed from 1,2-propylene glycol, caprylic acid and capric acid,

[0038] and mixtures thereof.

[0039] Preferably, the lubricating composition according to the present invention comprises, relative to the total weight of the lubricating composition:

[0040] - One or more diesters selected from the group consisting of:

[0041] o Diesters formed between:

[0042] a diol selected from 1,2-decanediol and 1,3-propylene glycol, and

[0043] two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, and

[0044] ο diester formed from 1,2-propylene glycol and two heptanoic acids,

[0045] ο diester formed from 1,2-propylene glycol and two octanoic acids,

[0046] ο diester formed from 1,2-propylene glycol and two capric acids,

[0047] ο diesters formed from 1,2-propylene glycol, caprylic acid and capric acid,

[0048] and mixtures thereof, and

[0049] at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

[0050] The invention also relates to the use of at least one diester in a lubricating composition,

[0051] The diester is formed between:

[0052] - a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0053] - two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, and

[0054] The lubricating composition further comprises at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPDs), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

[0055] According to one embodiment, the at least one diester is used for lubricating and / or cooling at least one element of a mobile or stationary system selected from, for example, heavy or light vehicles, public works vehicles and energy storage systems.

[0056] Preferably, the mobile system is a vehicle and the lubricating composition is used to reduce fuel consumption of the vehicle equipped with a transmission member lubricated by the composition, in particular a transmission and / or an axle.

[0057] Preferably, the diester used in the use according to the invention is as defined within the framework of the lubricating composition according to the invention and / or the lubricating composition used in the use according to the invention is as defined within the framework of the lubricating composition according to the invention.

[0058] According to one embodiment, the present invention relates to the use of at least one diester in a lubricating composition for lubricating and / or cooling at least one element of a mobile or stationary system selected from public works vehicles and energy storage systems,

[0059] The diester is formed between:

[0060] - a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0061] - two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, and

[0062] The lubricating composition further comprises at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPDs), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

[0063] According to one embodiment, the present invention relates to the use of at least one diester in a lubricating composition for lubricating and / or cooling at least one element of a moving system, said moving system being a vehicle,

[0064] The diester is formed between:

[0065] - a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0066] - two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, and

[0067] The lubricating composition further comprises at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPDs), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof, and the lubricating composition is used to reduce fuel consumption of vehicles equipped with transmission components, in particular transmissions and / or shafts lubricated using the composition.

[0068] In the following, unless otherwise stated, expressions such as “included between… and…,” “ranged from… to…,” and “varying from… to…” are equivalent and mean to include these limitations.

[0069] Unless otherwise specified, the expression "comprising a" should be understood as "comprising at least one". DETAILED DESCRIPTION

[0070] First, the present invention relates to a lubricating composition, comprising:

[0071] - at least one diester formed between:

[0072] o a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0073] o two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, and

[0074] at least one ingredient selected from the group consisting of base oils other than diesters, additives other than diesters, and mixtures thereof, wherein the additives, when present, are selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators, and mixtures thereof.

[0075] The lubricating composition according to the present invention may comprise one or more diesters, each of which is formed between:

[0076] o—a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0077] o identical or different monocarboxylic acids, having a linear or branched hydrocarbon chain comprising 5 to 10 carbon atoms, and

[0078] More particularly, a mixture of diesters may be prepared by reacting a mixture of diols and monocarboxylic acids.

[0079] For example, diols and three monocarboxylic acids A1, A2 and A3 can be reacted. Thus, according to this embodiment, a mixture of diesters falling within the scope of the present invention may include:

[0080] - diesters formed between diols and two acids A1,

[0081] - diesters formed between diols and two acids A2,

[0082] - a diester formed between a diol and two acids A3,

[0083] - a diester formed between a diol, an acid A1 and an acid A2,

[0084] - a diester formed between a diol, an acid A1 and an acid A3,

[0085] - Diester formed between diol, acid A2 and acid A3.

[0086] The diesters used according to the invention

[0087] As mentioned above, the one or more diesters used according to the invention are formed between a diol and two monocarboxylic acids.

[0088] As defined in the present invention, "diester formed between a diol and two monocarboxylic acids" refers to a compound obtained by two esterification reactions, each esterification reaction being carried out between one of the two alcohol functions of the diol and the acid function of one of the two monocarboxylic acids.

[0089] According to a preferred embodiment, the diester has from 13 to 25 carbon atoms, preferably the diester has from 15 to 24 carbon atoms.

[0090] The diols used in the present invention are 1,2-propylene glycol, 1,2-decanediol and 1,3-diols including 3 to 10 carbon atoms.

[0091] "Diol" refers to a compound that includes (exactly) two hydroxyl functional groups (-OH).

[0092] “1,3-diol comprising X to Y carbon atoms” means a diol whose alcohol functions are respectively located in the 1-position and 3-position of a hydrocarbon chain comprising X to Y carbon atoms.

[0093] The "hydrocarbon chain" defined in the present invention refers to a straight or branched, saturated or unsaturated alkyl or alkylene chain. The hydrocarbon chain may optionally be interrupted by one or more heteroatoms, more particularly, by one or more oxygen atoms. Preferably, the hydrocarbon chain is a straight or branched, saturated or unsaturated alkyl or alkylene chain consisting of carbon atoms and hydrogen atoms.

[0094] According to one embodiment, the 1,3-diol having 3 to 10 carbon atoms is chosen from 1,3-alkanediols having 3 to 10 carbon atoms.

[0095] “1,3-alkanediol having X to Y carbon atoms” refers to a diol whose alcohol functions are respectively located at the 1-position and the 3-position of an alkane chain having X to Y carbon atoms.

[0096] According to one embodiment, the diol is chosen from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 7 carbon atoms, preferably from 1,2-propylene glycol and 1,3-alkanediols having 3 to 7 carbon atoms, more preferably from 1,2-propylene glycol and 1,3-propylene glycol, advantageously the diol is 1,2-propylene glycol.

[0097] The diols used according to the present invention can be obtained commercially or synthesized according to any method known to those skilled in the art.

[0098] Preferably, the diol used according to the invention comprises a carbon content of biogenic origin of at least 60% by weight, preferably at least 70% by weight, further preferably at least 80% by weight, further more preferably at least 90% by weight, relative to the total weight of the carbon atoms of the diol.

[0099] Within the framework of the present invention, the carbon content of biogenic origin can be measured according to Standard ASTM D6866.

[0100] The diesters used according to the invention are obtained from two identical or different monocarboxylic acids.

[0101] "Monocarboxylic acid" refers to a compound that includes a single carboxyl functional group (-COOH).

[0102] The hydroxycarboxylic acid used to form the diester of the present invention is selected from monocarboxylic acids having a linear hydrocarbon chain having 4 to 10 carbon atoms, preferably 5 to 9 carbon atoms, further preferably 5 to 8 carbon atoms. Preferably, the linear or branched hydrocarbon chain of the monocarboxylic acid is saturated.

[0103] According to one embodiment, the identical or different monocarboxylic acids comprise a linear hydrocarbon chain having 5 to 10 carbon atoms, preferably 5 to 9 carbon atoms, further preferably 5 to 8 carbon atoms.

[0104] According to one embodiment, the identical or different monocarboxylic acids comprise a saturated linear hydrocarbon chain having 5 to 10 carbon atoms, preferably 5 to 9 carbon atoms, further preferably 5 to 8 carbon atoms.

[0105] The monocarboxylic acids used according to the present invention can be obtained commercially or synthesized according to any method known to those skilled in the art.

[0106] Preferably, the monocarboxylic acid used according to the invention comprises a carbon content of biogenic origin of at least 60% by weight, preferably at least 70% by weight, further preferably at least 80% by weight, further more preferably at least 90% by weight, relative to the total weight of the carbon atoms of the diol.

[0107] Preferably, the diesters used in the present invention are saturated.

[0108] The "saturated diester" defined in the present invention refers to a diester having a saturated hydrocarbon chain. Therefore, preferably, the diol used according to the present invention comprises a saturated hydrocarbon chain, and the monocarboxylic acid used according to the present invention each comprises a saturated hydrocarbon chain. Preferably, the hydrocarbon chain consists of carbon atoms and hydrogen atoms.

[0109] According to a particular embodiment, the diester used according to the invention is a branched diester.

[0110] The "branched diester" defined in the present invention refers to a diester having a branched hydrocarbon chain, which may be located between two ester functional groups and / or at one or both ends of the diester.

[0111] According to a preferred embodiment, the diesters used in the present invention are saturated and branched.

[0112] According to an embodiment, the diester used according to the invention has a kinematic viscosity at 100° C. measured according to standard ASTM D445 of 1 mm 2 / s to 6mm 2 / s range, preferably within 1mm 2 / s to 4mm 2 / s range.

[0113] According to an embodiment, the diester according to the invention has a kinematic viscosity at 40° C. measured according to standard ASTM D445 of 2 mm 2 / s to 20mm 2 / s range, preferably within 3mm 2 / s to 10mm 2 / s range.

[0114] It will be appreciated that the above definitions of carboxylic acids and alcohols may be combined as much as possible to define other specific embodiments.

[0115] The diester used according to the invention may more particularly correspond to one of the following formulae (I), (II) or (III):

[0116]

[0117]

[0118] in:

[0119] οR 1 denotes a linear or branched, saturated or unsaturated, preferably saturated, hydrocarbon chain having 3 to 9 carbon atoms, preferably 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms, said hydrocarbon chain possibly being interrupted by one or more heteroatoms (such as oxygen atoms), preferably the hydrocarbon chain consisting of carbon atoms and hydrogen atoms; and

[0120] οR 2 It refers to a straight or branched, saturated or unsaturated, preferably saturated, hydrocarbon chain having 3 to 9 carbon atoms, preferably 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms, which hydrocarbon chain may be interrupted by one or more heteroatoms (such as oxygen atoms), preferably the hydrocarbon chain consists of carbon atoms and hydrogen atoms.

[0121] Preferably, the one or more diesters corresponding to formula (I), (II) or (III) have from 13 to 25 carbon atoms, preferably the diester has from 15 to 24 carbon atoms.

[0122] In the diester of formula (I), (II) or (III), R 1 and R 2 Can be the same or different.

[0123] According to one embodiment, the one or more diesters used according to the invention are chosen from:

[0124] — diester formed from 1,2-decanediol and two heptanoic acids,

[0125] — diesters formed from 1,2-decanediol and two valeric acids,

[0126] - a diester formed from 1,2-propylene glycol and two heptanoic acids,

[0127] — diesters formed from 1,2-propylene glycol and two nonanoic acids,

[0128] - a diester formed from 1,3-propanediol and two heptanoic acids,

[0129] — a diester formed from 1,2-propylene glycol and two octanoic acids,

[0130] - a diester formed from 1,2-propylene glycol and two capric acids,

[0131] - a diester formed from 1,2-propylene glycol and an acid mixture comprising caprylic acid and capric acid,

[0132] and mixtures thereof.

[0133] The diesters according to the invention can be prepared according to synthesis methods known to those skilled in the art. The synthesis method more particularly employs two esterification reactions, each esterification reaction being carried out between an alcohol function of a diol and an acid function of a monocarboxylic acid.

[0134] Of course, a person skilled in the art will adjust the synthesis conditions to obtain the diesters according to the invention.

[0135] It will be understood that, within the framework of the present invention, the diester according to the invention may be in the form of a mixture of at least two diesters according to the invention, more particularly diesters as defined above.

[0136] Preferably, the diester used according to the invention comprises a carbon content of biogenic origin of at least 60% by weight, preferably at least 70% by weight, further preferably at least 80% by weight, further more preferably at least 90% by weight, relative to the total weight of the carbon atoms of the diester.

[0137] Within the framework of the present invention, the carbon content of biogenic origin can be measured according to Standard ASTM D6866.

[0138] The diester or diester mixture according to the invention may represent at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, more preferably at least 50% by weight, further more preferably at least 70% by weight, more particularly at least 80% by weight, more particularly at least 90% by weight, or even at least 95% by weight of the total weight of the composition according to the invention.

[0139] One or more diesters according to the invention can be used together with one or more auxiliary base oils (also called co-bases). According to one embodiment, the composition comprises, relative to the total weight of the one or more diesters and base oils other than the diesters:

[0140] - 5 to 95% by weight, preferably 5 to 50% by weight, more preferably 10 to 40% by weight, of one or more diesters according to the invention, and

[0141] - 5% to 95% by weight, preferably 50% to 95% by weight, preferably 60% to 90% by weight, of one or more different base oils according to the invention.

[0142] According to one embodiment, the lubricating composition according to the invention may comprise at least 30% by weight, more particularly between 50% and 99.5% by weight, preferably between 70% and 99% by weight, more preferably between 80% and 99% by weight, or even between 80% and 95% by weight of a diester or a mixture of diesters according to the invention, relative to the total weight of the composition.

[0143] According to a particular embodiment, the lubricating composition according to the invention may be formed from more than 95% by weight, more particularly more than 98% by weight, of one or more diesters according to the invention.

[0144] According to a particular embodiment, the composition according to the invention is a composition comprising 100% by weight of a mixture of one or more diesters as defined in the present invention and one or more additional base oils, preferably in proportions such that, relative to the total weight of the composition, the composition comprises:

[0145] - 5 to 95% by weight, preferably 5 to 50% by weight, more preferably 10 to 40% by weight, of one or more diesters according to the invention, and

[0146] - 5% to 95% by weight, preferably 50% to 95% by weight, preferably 60% to 90% by weight, of one or more different base oils according to the invention.

[0147] This embodiment is particularly advantageous when the composition is used as a cooling fluid for cooling.

[0148] One or more auxiliary base oils (co-base)

[0149] Besides the diester or diesters according to the invention, the lubricating composition according to the invention may also comprise one or more base oils different from the diesters according to the invention, called "auxiliary base oils".

[0150] The base oil optionally present in the lubricating composition according to the invention is suitably chosen with regard to its compatibility with the diester or diesters used according to the invention.

[0151] Mixtures of various base oils may be present, for example mixtures of two, three or four base oils.

[0152] Preferably, the base oil or the mixture of auxiliary base oils used in the lubricating composition according to the invention has a kinematic viscosity at 100° C. measured according to standard ASTM D445 of between 1.5 mm 2 / s to 8mm 2 / s range, especially within 1.5mm 2 / s to 6.1mm 2 / s range, more particularly within 1.5 mm 2 / s to 4.1mm 2 / s range, even more particularly within 1.5 mm 2 / s to 2.1mm 2 / s range.

[0153] The base oil may be chosen from mineral oils or synthetic oils belonging to groups I to V according to the categories defined by the API classification (or its equivalent according to the ATIEL classification) and shown in Table 1 below, or mixtures thereof.

[0154]

Table 1

[0155]

[0156] Mineral base oils include any type of base oil obtained by atmospheric and vacuum distillation of crude oil followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0157] It is further possible to use mixtures of synthetic oils, which may be of biological origin, and mineral oils.

[0158] The base oil may also be chosen from synthetic oils, such as certain carboxylic acid esters and alcohol esters different from the esters defined according to the invention, from polyalphaolefins (PAOs), and polyalkylene glycols (PAGs) obtained by polymerization or copolymerization of alkylene oxides comprising from 2 to 8 carbon atoms, more particularly from 2 to 4 carbon atoms.

[0159] The PAO used as base oil is obtained, for example, from monomers comprising 4 to 32 carbon atoms, for example from octene or decene.

[0160] The weight average molecular weight of PAO varies greatly. Preferably, the weight average molecular weight of PAO is less than 600Da. The weight average molecular weight of PAO can also be in the range of 100Da to 600Da, 150Da to 600Da, or 200Da to 600Da.

[0161] For example, the PAO used in the context of the present invention has a kinematic viscosity at 100° C. measured according to standard ASTM D445 of 1.5 mm 2 / s to 8mm 2 / s range, by INEOS with the trademark 162, 164, 166 and 168 for commercial sale.

[0162] Advantageously, the additional base oil is chosen from polyalphaolefins (PAO).

[0163] A person skilled in the art will adjust the content of the auxiliary base oil(s) used in the composition according to the invention.

[0164] More particularly, the composition according to the invention may comprise from 5% to 95% by weight, preferably from 50% to 95% by weight, further preferably from 60% to 90% by weight, of one or more base oils different from the diesters according to the invention, relative to the total weight of the composition.

[0165] additive

[0166] The lubricating composition according to the invention may optionally further comprise one or more additives known to those skilled in the art of lubrication, more particularly for vehicle transmissions, in particular light or heavy vehicle transmissions.

[0167] The additives may be selected in particular from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

[0168] Preferably, the lubricating composition according to the present invention may further include one or more additives selected from antioxidants, defoamers, pour point improvers and corrosion inhibitors.

[0169] It will be appreciated that the choice of the nature and amount of the additives used will not affect the properties imparted to the lubricating composition by the diester according to the invention.

[0170] Such additives may be introduced alone and / or as a mixture of additives similar to those already marketed for commercial lubricant formulations useful in vehicle engines, having performance levels defined by the European Automobile Manufacturers Association (ACEA) and / or the American Petroleum Institute (API) well known to those skilled in the art.

[0171] The additive or additives may be present in the lubricating composition according to the invention in a content less than or equal to 10% by weight, more particularly less than or equal to 5% by weight and more particularly within a range from 0.01% to 3% by weight relative to the total weight of the composition.

[0172] The lubricating composition according to the invention may also comprise at least one antioxidant.

[0173] Thus, according to one of its aspects, the present invention relates to a lubricating composition comprising (i) at least one diester as defined above, and (ii) at least one antioxidant.

[0174] Antioxidants generally retard the degradation of the composition during use. Such degradation is generally manifested by the formation of deposits in the presence of sludge or an increase in the viscosity of the composition.

[0175] Antioxidants act, inter alia, as free radical inhibitors or hydroperoxide destroyers.

[0176] Commonly used antioxidants include phenolic antioxidants, amine antioxidants and phosphorus-sulfur antioxidants. Some of these antioxidants, such as phosphorus-sulfur antioxidants, produce ash. Phenolic antioxidants may be ash-free or in the form of neutral or alkaline metal salts. The antioxidant may be selected from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols including thioether bridges, diphenylamine, esters of at least one C1-C 12 Preferably, the sterically hindered phenol is selected from compounds comprising a phenolic moiety in which at least one carbon adjacent to the carbon atom bearing the alcohol functional group is replaced by at least one C1-C 10 The amine compounds are another class of antioxidants that can be used in combination with phenolic antioxidants. Examples of amine compounds are aromatic amines, such as those having the formula NR 5R 6 R 7 Aromatic amines, where R 5 represents an aliphatic moiety or an aromatic moiety which may be substituted, R 6 represents the aromatic moiety which may be substituted, R 7 represents a hydrogen atom, an alkyl moiety, an aryl moiety or a group having the formula R 8 S(O) z R 9 part, where R 8 represents an alkylene or alkenylene moiety, R 9 represents an alkyl moiety, an alkenyl moiety or an aryl moiety, and z is 0, 1 or 2. The sulfoalkylphenol or the alkali metal salt or alkaline earth metal salt thereof can further be used as an antioxidant.

[0177] Advantageously, the lubricating composition comprises at least one ash-free antioxidant.

[0178] In the lubricating composition according to the invention, the additive(s) may be used in a proportion of 0.1% to 2% by weight relative to the total mass of the composition.

[0179] The lubricating composition according to the invention may comprise at least one antiwear agent, one extreme pressure agent or a mixture thereof.

[0180] Antiwear agents and extreme pressure agents protect surfaces subject to friction by forming a protective film that adsorbs onto the surface.

[0181] There are many types of anti-wear agents. Preferably, the anti-wear agent is selected from phosphorus-sulfur additives, such as metal alkylthiophosphates, more particularly zinc alkylthiophosphates, more particularly zinc dialkyl dithiophosphates or ZnDTP. Preferred compounds have the formula Zn((SP(S)(OQ 2 )(OQ 3 ))2, where Q 2 and Q 3 -same or different- independently represent an alkyl moiety, preferably an alkyl moiety comprising 1 to 18 carbon atoms.

[0182] Preferably, the lubricating composition according to the present invention does not contain esters, such as sulfur-containing phosphites of the formula

[0183] [Chemistry 4]

[0184]

[0185] Where R is C4 to C 20 hydrocarbon part, and R 1 is hydrogen, C4 to C 20 The hydrocarbon part or sulfur-containing C4 to C 20 Hydrocarbon part.

[0186] Phosphate amines are also antiwear agents and can be used in the lubricating compositions according to the invention. However, the phosphorus provided by such additives can act as inhibitors in the catalytic systems of automobiles because they produce ash. This effect can be minimized by partially replacing the phosphate amines with additives that do not bring phosphorus, such as polysulfides and, in particular, sulfur olefins.

[0187] The lubricating composition may comprise 0.01 to 6 wt %, preferably 0.05 to 4 wt %, more preferably 0.1 to 2 wt % of antiwear agents and extreme pressure agents relative to the total weight of the composition.

[0188] The lubricating composition according to the present invention may also include an antifoaming agent.

[0189] The defoaming agent may be selected from silicones.

[0190] The lubricating composition may comprise 0.01 wt % to 2 wt % or 0.01 wt % to 5 wt %, preferably 0.1 wt % to 1.5 wt % or 0.1 wt % to 2 wt % of antifoaming agent relative to the total weight of the composition.

[0191] The lubricating composition according to the invention may also comprise at least one friction modifier.

[0192] Friction modifiers limit friction by forming an adsorbed monolayer on the metal surface in contact with it. The friction modifier can be selected from compounds that provide metal elements and ashless compounds. Compounds that provide metal elements include transition metal complexes such as Mo and Sb. Sn, Fe, Cu, Zn, and their ligands can be hydrocarbon compounds including oxygen, nitrogen, sulfur or phosphorus atoms. Ashless friction modifiers are generally derived from organic matter and can be selected from fatty acids and polyol esters (different from the monoesters required according to the present invention), alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, amino acids or fatty acid glycerides. According to the present invention, the fatty compound includes at least one hydrocarbon part including 10 to 24 carbon atoms. More particularly, the molybdenum compound can be selected from molybdenum dithiocarbamate (Mo-DTC), molybdenum dithiophosphate (Mo-DTP) and mixtures thereof. The lubricating composition can particularly include a molybdenum content of 1000 ppm to 2500 ppm.

[0193] The lubricating composition may include 0.01 wt. % to 5 wt. %, more preferably 0.1 wt. % to 2 wt. %, or even more preferably 0.1 wt. % to 1.5 wt. % of friction modifier relative to the total weight of the composition.

[0194] When the content of the molybdenum compound is too high, it will have a negative impact on the low temperature properties of the lubricating composition using the molybdenum compound. Therefore, the lubricating composition according to the present invention preferably includes less than 1.5 wt. %, more preferably less than 1 wt. % of molybdenum, or even contains no molybdenum, relative to the total weight of the composition.

[0195] The lubricating composition according to the invention may comprise at least one detergent.

[0196] Detergents generally reduce the formation of deposits on the surfaces of metal parts by dissolving oxidation and combustion byproducts.

[0197] Detergents that can be used in lubricating compositions are generally known to those skilled in the art. The detergent may be an anionic compound comprising a lipophilic hydrocarbon portion and a hydrophilic head. The associated cation may be a metal cation of an alkali metal or an alkaline earth metal.

[0198] The detergent is preferably selected from alkali metal or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates and phenates. The alkali metal and alkaline earth metal are preferably calcium, magnesium, sodium or barium.

[0199] Such metal salts typically include a stoichiometric amount or an excess of the metal, i.e., a concentration greater than the stoichiometric amount. This is also true for overbased detergents; the excess metal that renders the detergent overbased is typically in the form of an oil-insoluble metal salt, such as a carbonate, hydroxide, oxalate, acetate, glutamate, preferably a carbonate.

[0200] The lubricating composition may, for example, comprise from 2% to 4% by weight of detergent relative to the total weight of the composition.

[0201] The lubricating composition according to the invention may also comprise at least one pour point depressant (PPD).

[0202] Pour point depressants generally improve the behavior of the composition under low temperature conditions by slowing down the formation of paraffin crystals. Examples of pour point depressants include alkyl polymethacrylates, polyacrylates, polyaromatic amides, polyalkylphenols, polyalkylnaphthalenes, alkylpolystyrenes.

[0203] The lubricating composition according to the invention may comprise from 0.1% to 2%, preferably from 0.2% to 1% of pour point depressant relative to the total weight of the composition.

[0204] Furthermore, the lubricating composition may include at least one dispersant.

[0205] The dispersant may be selected from Mannich bases, succinimide and derivatives thereof, such as derivatives of polyisobutylene succinic anhydride.

[0206] The lubricating composition may, for example, comprise 0.2% to 10% by weight of dispersant relative to the total weight of the composition.

[0207] The lubricating composition used according to the present invention may include at least one viscosity index (VI) improver.

[0208] Viscosity index improvers, more particularly viscosity index improving polymers, provide good cold resistance and minimum viscosity at high temperatures.

[0209] Examples of viscosity index increasing polymers include polymer esters, hydrogenated or non-hydrogenated homopolymers or copolymers of styrene, butadiene and isoprene, homopolymers or copolymers of olefins such as ethylene or propylene, polyacrylates and polymethacrylates (PMA), preferably homopolymers or copolymers of olefins such as ethylene or propylene.

[0210] More particularly, the lubricating composition according to the invention may comprise from 1% to 15% by weight, preferably from 5% to 10% by weight, of one or more additives that improve the viscosity index, relative to the total weight of the composition.

[0211] The lubricating composition may also comprise at least one antifoaming additive, for example chosen from polar polymers such as polymethylsiloxanes or polyacrylates.

[0212] More particularly, the lubricating composition according to the invention may comprise from 0.01% to 3% by weight of one or more additives relative to the total weight of the composition.

[0213] The lubricating composition according to the invention may also include at least one corrosion inhibitor or copper passivator, such as compounds such as polyisobutylene succinic anhydride, thiadiazole sulfonate or mercaptobenzothiazole, etc. The corrosion inhibitor or copper passivator is generally present in the lubricating composition according to the invention in an amount between 0.01% and 1% by weight relative to the total weight of the composition.

[0214] Advantageously, the lubricating composition according to the invention comprises one or more additives selected from viscosity index improvers, pour point depressants, antiwear agents and antioxidants.

[0215] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of, (i) at least one diester according to the invention and (ii) at least one additive selected from antioxidants, viscosity index improvers, pour point depressants, antiwear agents and / or extreme pressure agents, defoamers, detergents, dispersants and mixtures thereof, preferably antioxidants, viscosity index improvers, pour point depressants, antiwear agents and extreme pressure agents and mixtures thereof.

[0216] Advantageously, the lubricating composition according to the invention is formed from (i) at least one diester corresponding to one of the formulae (I), (II) or (III) defined above and (ii) at least one antioxidant.

[0217] Advantageously, the lubricating composition according to the invention is formed from (i) at least one diester corresponding to one of the formulae (I) or (II) defined above and (ii) at least one antioxidant.

[0218] According to a particular embodiment, the composition according to the invention comprises or even consists of:

[0219] at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, preferably at least 50% by weight, more preferably at least 70% by weight or even at least 90% by weight of one or more diesters corresponding to one of the formulae (I), (II) or (III);

[0220] 0.01 to 20 wt. %, preferably 0.05 to 15 wt. %, more preferably 0.1 to 10 wt. %, still more preferably 0.5 to 7 wt. % or even 1 to 5 wt. % of one or more additives selected from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper thickeners and mixtures thereof; and

[0221] - optionally, 5 to 94% by weight, preferably 10 to 94% by weight, preferably 15 to 90% by weight, of one or more base oils different from the diesters according to the invention,

[0222] The content is expressed relative to the total weight of the composition.

[0223] According to a particular embodiment, the composition according to the invention comprises or even consists of:

[0224] 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 20 to 80% by weight, even more preferably 30 to 70% by weight or even 40 to 60% by weight of one or more diesters corresponding to one of the formulae (I), (II) or (III);

[0225] 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 20 to 80% by weight, further more preferably 30 to 70% by weight or even 40 to 60% by weight of one or more base oils other than diesters,

[0226] - optionally, 0.01% to 20% by weight, preferably 0.05% to 15% by weight, further preferably 0.1% to 10% by weight, even more preferably 0.5% to 7% by weight or even 1% to 5% by weight of one or more additives other than diesters and other than the base oil or oils,

[0227] The content is expressed relative to the total weight of the composition.

[0228] According to a particular embodiment, the lubricating composition according to the invention comprises or even consists of:

[0229] at least 5% by weight, preferably from 10% to 40% by weight, more preferably from 15% to 30% by weight, of one or more diesters according to the invention as defined above, preferably chosen from the diesters corresponding to formula (I);

[0230] - 50% to 95% by weight of one or more base oils other than diesters as defined according to the invention, preferably chosen from group II and / or group III base oils according to the API classification;

[0231] - optionally, 5 to 15 wt. % of at least one viscosity index improver;

[0232] - Optionally, 0.1% to 1% by weight of at least one pour point depressant;

[0233] - optionally, 0.01 to 6 wt. % of at least one antiwear agent; and

[0234] - Optionally, 0.1 to 2% by weight of at least one antioxidant;

[0235] The content is expressed relative to the total weight of the composition.

[0236] Preferably, the lubricating composition according to the invention comprises or even consists of:

[0237] - less than 30% by weight, more particularly from 1 to 30% by weight, in particular from 5 to 30% by weight, preferably from 10 to 30% by weight, more particularly from 15 to 30% by weight, of one or more diesters according to the invention as defined above, preferably chosen from diesters of formula (I) or (II);

[0238] - 50% to 85% by weight of one or more base oils other than diesters as defined according to the invention, preferably chosen from group II and / or group III base oils according to the API classification;

[0239] - optionally, 5 to 15 wt. % of at least one viscosity index improver;

[0240] - Optionally, 0.1% to 1% by weight of at least one pour point depressant;

[0241] - optionally, 0.01 to 6 wt. % of at least one antiwear agent; and

[0242] - Optionally, 0.1 to 2% by weight of at least one antioxidant;

[0243] The content is expressed relative to the total weight of the composition.

[0244] According to a particular embodiment, the composition according to the invention comprises or even consists of:

[0245] - 5 to 95% by weight, preferably 5 to 50% by weight, further preferably 10 to 40% by weight, of the one or more diesters corresponding to formula (I) or (II);

[0246] - 5 to 95% by weight, preferably 50 to 95% by weight, preferably 60 to 90% by weight, of one or more different said diesters;

[0247] 0.01 to 20 wt. %, preferably 0.05 to 15 wt. %, more preferably 0.1 to 10 wt. %, further more preferably 0.5 to 7 wt. % or even 1 to 5 wt. % of one or more additives selected from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof; and

[0248] The content is expressed relative to the total weight of the composition.

[0249] The composition according to the invention advantageously has a kinematic viscosity at 100° C., measured according to standard ASTM D445, of 1 mm 2 / s to 20mm 2 / s range, preferably within 2mm 2 / s to 15mm 2 / s range.

[0250] The composition according to the invention advantageously has a kinematic viscosity at 40° C., measured according to standard ASTM D445, of 20 mm 2 / s to 50mm 2 / s range, preferably within 25mm 2 / s to 40mm 2 / s range.

[0251] The compositions according to the invention have good lubricating properties.

[0252] The composition according to the invention also has good properties in terms of cold resistance.

[0253] The compositions according to the invention also have good cooling properties.

[0254] Another subject of the invention relates to the use of the diesters in a composition for lubricating and / or cooling at least a part of a mobile or stationary system,

[0255] The diester is formed between:

[0256] - a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and

[0257] - identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms.

[0258] Preferably, the composition for lubrication and / or cooling further comprises at least one base oil different from the diester and / or at least one additive different from the diester, the additive being chosen from antioxidants, pour point depressants, defoamers, corrosion inhibitors, antiwear agents and / or extreme pressure agents, friction modifiers, detergents, dispersants and mixtures thereof, more particularly chosen from antioxidants, pour point depressants, defoamers and corrosion inhibitors.

[0259] One or more features of the diesters presented in the context of the composition according to the invention also apply to the diesters used according to the invention.

[0260] According to one embodiment of the use according to the invention, the lubricating and / or cooling component is part of a heavy or light vehicle, a public works machine or an energy storage device, such as a data center.

[0261] The diesters defined in the present invention are used to reduce the coefficient of friction of lubricating compositions.

[0262] The diesters defined in the invention make it possible to cool components of mobile or stationary systems, such as heavy or light vehicles, public works machinery and energy storage devices.

[0263] The composition formulated according to the invention, more particularly as described above, has excellent tribological properties, in particular in terms of friction reduction, which makes it particularly suitable for use as a lubricating fluid.

[0264] The composition formulated according to the invention, more particularly as described above, has excellent thermal properties, in particular in terms of thermal conductivity, which makes it particularly suitable for use as a cooling fluid.

[0265] The composition of the invention is suitable for lubricating transmission components of motor vehicles, in particular transmissions of light or heavy vehicles, such as transmissions and / or axles.

[0266] More particularly, the composition of the invention can be used to lubricate manual transmissions and / or axles of light or heavy vehicles. Advantageously, the lubricating composition according to the invention has properties (more particularly in terms of low temperature properties) that are particularly suitable for use in heavy vehicle transmissions, more particularly for lubricating manual transmissions and / or heavy vehicle axles.

[0267] The invention also relates to a method for lubricating and / or cooling at least one component of a moving or stationary system, comprising bringing the composition according to the invention into contact with said component.

[0268] According to one embodiment, the mobile or stationary system is selected from a heavy or light vehicle, a utility machine, an energy storage device such as a data center.

[0269] The invention also relates to a method for lubricating and / or cooling at least one mechanical part, in particular a motor vehicle transmission component, comprising bringing a lubricating composition according to the invention into contact with said mechanical part, more particularly with said motor vehicle transmission component.

[0270] The diesters defined in the present invention can be added to lubricating compositions used in vehicle transmissions in order to improve their "fuel economy" properties, ie their ability to limit the fuel consumption of motor vehicles, without affecting their performance, in particular in terms of low temperature properties.

[0271] The present invention will now be described by way of the following examples which are, of course, illustrative of the present invention but not limiting thereof.

[0272] Example

[0273] Example 1: Preparation of test compounds

[0274] The following compounds were prepared:

[0275] — Diester A: Diester formed from 1,2-decanediol and two heptanoic acids

[0276] — Diester B: Diester formed from 1,2-decanediol and two valeric acids

[0277] — Diester C: Diester formed from 1,2-propylene glycol and two heptanoic acids

[0278] —Diester D: Diester formed from 1,2-propylene glycol and two nonanoic acids

[0279] — Diester E: Diester formed from 1,3-propanediol and two heptanoic acids

[0280] — Diester F: A mixture of diesters formed from 1,2-propylene glycol and a bio-based fraction of C8-C10 acids

[0281] - monoesters formed from monocarboxylic acids having a saturated hydrocarbon chain of 3 to 14 carbon atoms; and monoalcohols having a saturated hydrocarbon chain of 3 to 14 carbon atoms.

[0282] The diesters and monoesters are prepared according to known methods for the preparation of esters.

[0283] The compositions tested in the examples below comprised 100% of each of the esters defined in Example 1 (either diester or monoester).

[0284] Example 2: Viscosity Measurement

[0285] The kinematic viscosity at 100° C. (KV100) and at 40° C. (KV 40) was determined according to standard ASTM D445.

[0286] The viscosities are shown in Table 2.

[0287]

Table 2

[0288] <![CDATA[KV100(mm 2 / s)]]> <![CDATA[KV40(mm 2 / s)]]> Diester A 2.38 7.916 Diester B 1.856 5.659 Diester C 1.55 4.236 Diester D 1.878 5.503 Diester E 1.7404 4.7422 Diester F 2.147 6.61 Monoester 1.8 5.2

[0289] All diesters used according to the invention have a viscosity of less than 4 mm at 100°C. 2 / s.

[0290] Example 3: Measurement of friction coefficient

[0291] Tribological properties can be evaluated by testing on a ball-on-disc rotating tribometer (also called a ball-on-plane), such as a linear reciprocating tribometer. This test is used to evaluate the friction performance of a lubricant under mixed / extreme conditions, depending on applied load, pressure or speed conditions.

[0292] The coefficient of friction of the lubricating compositions tested was determined at 40°C by using a hardened steel ball of approximately 2 cm in diameter (eg, 1.905 cm in diameter) on a hardened steel flat surface.

[0293] A tribometer may be a device that provides for the relative motion of a steel ball and a steel plane in order to determine the friction / friction coefficient of a given lubricating composition while varying various characteristics such as speed, load and temperature. The hardened steel surface has an AISI 52100 reference with a mirror finish and the ball also has an AISI 52100 reference and is made of hardened steel.

[0294] The applied load was 25 N and the driving speed was 10 mm / s to 2500 mm / s. More specifically, the friction coefficient was measured at a rotation speed of 10 mm / s. The coefficient was measured at a sliding to rolling ratio (%SRR) of 5%.

[0295] About 50 ml of the lubricating composition to be tested was added to the apparatus. The balls were engaged face to face, with the ball and the plane being independently actuated to produce a mixed rolling / sliding contact.

[0296] The friction coefficient is measured and recorded by a force sensor.

[0297] Table 3 gives the driving speed of 225 mm 2 / s results.

[0298] The lubricating compositions tested included 100% of each of the esters defined in Example 1 .

[0299]

Table 3

[0300] Friction coefficient – ​​25N – 40°C – 5% SRR Diester A 0.0053 Diester B 0.0069 Diester C 0.0214 Diester D 0.013 Diester E 0.019 Diester F 0.0105 Monoester 0.0371

[0301] The results show that the diesters used according to the invention have a very low coefficient of friction, more particularly a coefficient of friction lower than that of the monoesters.

[0302] Example 4: Minimum flash point measurement

[0303] The minimum flash point is measured according to standard ASTM D93Ac (Cleveland open cup method).

[0304] These values ​​are shown in Table 4.

[0305]

Table 4

[0306] Minimum flash point (℃) Diester A 157.6 Diester B 174.6 Diester C 144 Diester D 186.5 Diester E 174.5 Diester F 166.6 Monoester 164.9

[0307] As shown by the values ​​in Table 4, the flash point is better when the diester is a branched diester. In fact, with the same total number of carbon atoms, the flash point of the diester formed from 1,2-propylene glycol is lower than that of the diester formed from 1,3-propylene glycol.

[0308] Example 5: Measurement of minimum pour point

[0309] The minimum pour point is measured according to standard ASTM D7346.

[0310] These values ​​are shown in Table 5.

[0311]

Table 5

[0312] Minimum pour point(℃) Diester A -69 Diester B -87 Diester C -90 Diester D -48 Diester F -69 Monoester -34

[0313] The results of Table 5 show that the diesters used in the lubricating compositions according to the invention have low pour points, more particularly lower than the monoesters.

[0314] Example 6: Measurement of traction coefficient

[0315] The coefficient of traction (COT) is measured using PCS Instrument's MTM Tribometer. The coefficient of traction is used to evaluate the friction performance of a lubricant under mixed / hydrodynamic conditions. The test involves moving a steel ball and a steel plane relative to each other at different speeds, allowing the definition of the sliding to rolling ratio (SSR) % corresponding to the sliding speed / drive speed.

[0316] The measurement conditions were a load of 25 N, a disk speed of 1.4 m / s at an estimated temperature of 100° C., and an SRR of 20%.

[0317] The lower the traction coefficient of a lubricating composition, the less friction there is between metal parts, resulting in greater fuel savings.

[0318] The results are shown in Table 6.

[0319]

Table 6

[0320]

[0321]

[0322] The results show that the diesters used according to the invention have a very low traction coefficient, more particularly a lower traction coefficient than the monoesters.

[0323] Example 7: Thermal conductivity measurement

[0324] According to ASTM D7896-19 standard, the thermal conductivity of the compound described in Example 1 was measured at different temperatures.

[0325] The results are shown in Table 7.

[0326]

Table 7

[0327]

[0328] The results show that the diesters defined in the present invention have good thermal properties, which allow them to be used as cooling fluids.

Claims

1. A lubricating composition comprising: - one or more diesters, each of which is formed between: o a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and o two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, said hydrocarbon chain optionally being interrupted by one or more heteroatoms, and at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

2. The lubricating composition according to claim 1, wherein the straight or branched hydrocarbon chain having 4 to 10 carbon atoms is a straight or branched, saturated or unsaturated alkyl or alkylene chain consisting of carbon atoms and hydrogen atoms.

3. The lubricating composition according to claim 1 or 2, comprising, relative to the total weight of the composition: 5 to 95% by weight, preferably 10 to 90% by weight, further preferably 20 to 80% by weight, further more preferably 30 to 70% by weight or even 40 to 60% by weight of the one or more diesters, 1% to 95% by weight, preferably 10% to 90% by weight, more preferably 20% to 80% by weight, further more preferably 30% to 70% by weight or even 40% to 60% by weight of one or more base oils different from the diesters, - Optionally, 0.01 to 20% by weight, preferably 0.05 to 15% by weight, further preferably 0.1 to 10% by weight, further more preferably 0.5 to 7% by weight or even 1 to 5% by weight of one or more additives different from the diester and different from the one or more base oils.

4. The lubricating composition according to any one of claims 1 to 3, comprising, relative to the total weight of the composition: at least 5% by weight, preferably at least 10% by weight, preferably at least 30% by weight, preferably at least 50% by weight, more preferably at least 70% by weight or even at least 90% by weight of one or more diesters; 0.01 to 20 wt. %, preferably 0.05 to 15 wt. %, more preferably 0.1 to 10 wt. %, still more preferably 0.5 to 7 wt. % or even 1 to 5 wt. % of one or more additives selected from friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, defoamers, thickeners, copper thickeners, corrosion inhibitors and mixtures thereof; and - Optionally, 5 to 94% by weight, preferably 10 to 94% by weight, preferably 15 to 90% by weight, of one or more base oils different from the diesters according to the invention.

5. The lubricating composition according to any one of the preceding claims, wherein the diester has from 13 to 25 carbon atoms, preferably the diester has from 13 to 24 carbon atoms.

6. A lubricating composition according to any one of the preceding claims, wherein the diester has a kinematic viscosity at 100°C of 1 mm 2 / s to 6mm 2 / s range, preferably within 1mm 2 / s to 4mm 2 / s range.

7. The lubricating composition according to any one of the preceding claims, wherein the diol is selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-alkanediol having 3 to 7 carbon atoms, preferably the diol is selected from 1,2-propylene glycol and 1,3-propylene glycol, and more preferably the diol is 1,2-propylene glycol.

8. Lubricating composition according to any one of the preceding claims, wherein the same or different monocarboxylic acids comprise a linear hydrocarbon chain having from 4 to 10 carbon atoms, preferably from 5 to 9 carbon atoms.

9. The lubricating composition according to any one of the preceding claims, wherein the one or more diesters are selected from: - Diesters formed between: a diol selected from 1,2-decanediol and 1,3-propylene glycol, and two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, said hydrocarbon chain optionally being interrupted by one or more heteroatoms, - a diester formed from 1,2-propanediol and two heptanoic acids, — a diester formed from 1,2-propylene glycol and two octanoic acids, - a diester formed from 1,2-propylene glycol and two capric acids, - a diester formed from 1,2-propylene glycol, caprylic acid and capric acid, and mixtures thereof.

10. The lubricating composition according to any one of the preceding claims, wherein the one or more diesters are selected from: — diester formed from 1,2-decanediol and two heptanoic acids, — diesters formed from 1,2-decanediol and two valeric acids, - a diester formed from 1,2-propylene glycol and two heptanoic acids, — diesters formed from 1,2-propylene glycol and two nonanoic acids, - a diester formed from 1,3-propanediol and two heptanoic acids, — a diester formed from 1,2-propylene glycol and two octanoic acids, - a diester formed from 1,2-propylene glycol and two capric acids, - a diester formed from 1,2-propylene glycol, caprylic acid and capric acid, and mixtures thereof.

11. Use of at least one diester in a lubricating composition, The diester is formed between: - a diol selected from 1,2-propylene glycol, 1,2-decanediol and 1,3-diols having 3 to 10 carbon atoms, and - two identical or different monocarboxylic acids having a linear or branched hydrocarbon chain comprising 4 to 10 carbon atoms, said hydrocarbon chain being optionally interrupted by one or more heteroatoms, The lubricating composition further comprises at least one base oil different from the diester and / or at least one additive different from the diester, the additive being selected from the group consisting of friction modifiers, antiwear agents, extreme pressure agents, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPDs), dispersants, defoamers, thickeners, corrosion inhibitors, copper passivators and mixtures thereof.

12. Use according to claim 11 for lubricating and / or cooling at least one component of a mobile or stationary system, selected from the group consisting of heavy or light vehicles, public works vehicles and energy storage systems.

13. Use according to claim 12, wherein the mobile system is a vehicle and the lubricating composition is used to reduce the fuel consumption of the vehicle equipped with a transmission member lubricated by the composition, in particular, the transmission member is a transmission and / or an axle.

14. Use according to any one of claims 11 to 13, wherein the diester is as defined in any one of claims 2, 5 to 9 and / or the lubricating composition is as defined in claim 3 or 4.

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