Thickener for lubricating greases.

Abstract

The present invention relates to a process for preparing a grease comprising a hydroxyamine synthesis step including reaction R1 between at least one monoepoxy of formula (1) and at least one primary amine of formula (2) to obtain a hydroxyamine, said reaction R1 optionally being carried out in the presence of a base oil HB1, the grease being formed (i) in situ during reaction R1 or (ii) in a subsequent step to reaction R1 by mixing said hydroxyamines with a base oil HB2, wherein: R1 and R2 represent, independently of each other, a hydrogen atom or a group selected from hydrocarbon groups optionally comprising one or more heteroatoms, R3 represents a group selected from hydrocarbon groups optionally comprising one or more heteroatoms. Figure for the abstract: None

Description

Title of the invention: Thickener for lubricating greases.

[0001] The present invention relates to the field of thickeners for lubricating greases. technical field

[0002] There are many applications where liquid lubricants are unsuitable because they "drift" from the lubrication point. These include, in particular, rolling and sliding bearings, open gears, wire ropes and chain drives, and more generally, applications without a sealing system.

[0003] For these applications, lubricating greases are used, which are solid or semi-fluid substances resulting from the dispersion of a thickener in a liquid lubricant, possibly incorporating additives that give them particular properties.

[0004] Among the thickeners used in the manufacture of fats, we can mention in particular metallic salts of fatty acids, such as lithium salts, and polycarbamides (polyureas).

[0005] Lithium is used to prepare lithium salt-based thickeners.

[0006] In 2021, a circular from the European Commission proposed changing the classification of lithium into category CMR 1.

[0007] Polyurea-based greases are used in high-performance applications requiring significantly higher thermal and mechanical resistance than lithium greases. Polyurea thickeners are particularly well-suited to e-mobility (electric or hybrid mobility) due to their high-temperature resistance, long-term stability, oxidation stability, and high shear strength.

[0008] Polyurea thickeners are obtained by a reaction between isocyanate and amine. However, isocyanate, in particular of the methylene diisocyanate (MDI) type, has several disadvantages: it is unstable at room temperature, reactive to humidity, solid below 42°C, likely to be CMR and cannot be derived from bio-based raw material.

[0009] It is therefore an object of the present invention to provide a thickener that is not derived from isocyanate and that can be used in a lubricating grease. Summary of the invention

[0010] More specifically, the present invention relates to a process for preparing a fat comprising a step of synthesizing hydroxyamines comprising the reaction RI involves at least one monoepoxy of formula (1) and at least one primary amine of formula (2) to obtain a hydroxyamine,

[0011] said RI reaction possibly being carried out in the presence of a base oil HB1,

[0012] the grease being formed (i) in situ during the RI reaction or (ii) in a subsequent step to the RI reaction by mixing said hydroxyamines with a base oil HB2, HB2 being identical or different from the base oil HB1 possibly used during the RI reaction,

[0013] Formulas (1) and (2) being defined as follows:

[0014] [Chem.l] O

[0015] [Chem.2] H;?N R—

[0016] in which:

[0017] R1 represents a hydrogen atom or a group chosen from hydrocarbon groups possibly comprising one or more heteroatoms,

[0018] R2 represents a hydrogen atom or a group chosen from hydrocarbon groups possibly comprising one or more heteroatoms,

[0019] R3 represents a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms.

[0020] According to one embodiment of the process of the invention:

[0021] R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms,

[0022] R2 represents a hydrogen atom,

[0023] R3 represents a group selected from among the alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups.

[0024] According to one embodiment, the synthesis of hydroxy-amine leads to at least one compound corresponding to one of the formulas (3), (4), (5), (6) or (7):

[0025] [Chem.3] OH R' VR

[0026] [Chem.4] QH R' NH;

[0027] [Chem.5] OH OH

[0028] [Chem.6] OH OH RYY R- r

[0029] [Chem.7] OH OH -Jz.X JW RH A R- Y "y" fr A R1

[0030] in which R1, R2 and R3 are such as defined in formulas (1) and (2).

[0031] According to one embodiment, the amine of formula (2) is chosen from among the amines containing exactly two primary amine functions.

[0032] According to one embodiment, the amine of formula (2) is chosen from:

[0033] - dianiline-type compounds possibly comprising one or more substitutes,

[0034] - cyclohexyl type compounds comprising at least two substituents comprising at least one primary amine function, said two substituents being in meta or para positions relative to each other,

[0035] - monoaromatic compounds comprising at least two substituents comprising at least one primary amine function, said two substituents being in para positions relative to each other,

[0036] - alkylene diamine type compounds,

[0037] - polyether diamine type compounds.

[0038] According to one embodiment, the amine of formula (2) is selected from 4,4-methylenedianiline, isophorone diamine, para-phenylenediamine, diaminodecane, ethylene diamine, para-xylene diamine, polyether diamine of formula H2N-CH2-CH2-O-CH2-CH2-O-CH2-CH2-NH2, cadaverine, or a diamine of formula (8):

[0039] [Chem. 8] HsN S.

[0040] According to one embodiment, the monoepoxy of formula (1) is chosen from glycidyl hexadecyl ether.

[0041] According to one embodiment, the RI reaction of monoepoxy and amine of formula (2) to form hydroxyamine is carried out according to one or more of the following conditions:

[0042] - a temperature ranging from 50°C to 250°C, preferably from 120°C to 200°C,

[0043] - a duration ranging from 10 minutes to 48 hours, preferably from 20 minutes to 36 hours,

[0044] - an amine molar ratio of formula (2) / monoepoxy of formula (1) ranging from 0.1 to 2, preferably from 0.3 to 0.8.

[0045] According to one embodiment, the RI reaction comprising the reaction between a monoepoxy corresponding to formula (1) and a primary amine corresponding to formula (2) is carried out with a molar ratio amine of formula (2) / monoepoxy of formula (1) ranging from 0.1 to 2, preferably from 0.3 to 0.8.

[0046] According to one embodiment, the RI reaction comprising the reaction between a monoepoxy corresponding to formula (1) and a primary amine corresponding to formula (2) is carried out in the presence of at least one base oil HB1, preferably with a mass ratio base oil(s) HB1 / mixture {monoepoxy and amine] ranging from 70 / 30 to 98 / 2, preferably from 80 / 20 to 95 / 5.

[0047] According to one embodiment, the synthesis of hydroxy-amine leads to a mixture of several compounds, at least one of the compounds corresponding to one of the formulas (3), (4), (5), (6) or (7):

[0048] [Chem.3] OH

[0049] [Chem.4] OH the NHL

[0050] [Chem.5] OH OH i ..HH ..NH  , R' 'V "R '■] " OO 42 Jj RR

[0051] [Chem.6]

[0052] [Chem.7] OH OH

[0053] in which:

[0054] R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms,

[0055] R2 represents a hydrogen atom,

[0056] R3 represents a group selected from among the aryl groups of 6 to 15 carbon atoms, the cycloalkyl groups of 6 to 15 carbon atoms, the aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms.

[0057] The present invention also relates to a lubricating grease composition that can be obtained by the process according to the invention (or even obtained according to the invention), said grease composition comprising at least a base oil and a hydroxyamine-type thickener.

[0058] According to one embodiment of the lubricating grease composition according to the invention, the hydroxyamine-type thickener comprises at least one compound corresponding to one of the formulas (3), (4), (5), (6) or (7):

[0059] [Chem.3] OH 1X ..NH . RYR? HAS

[0060] [Chem.4] OH .. HH q rx y "A A NHq

[0061] [Chem.5] OH QH R1 f 'R -y' Or A R1

[0062] [Chem.6] OH Qh <X -NH y. NH A 1 r' yya AA

[0063] [Chem.7]

[0064] in which:

[0065] R1 represents a hydrogen atom or a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms, preferably again R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms,

[0066] R2 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms, preferably R2 represents a hydrogen atom,

[0067] R3 represents a group selected from among hydrocarbon groups possibly comprising one or more heteroatoms, preferably R3 represents a group selected from among alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups, preferably again R3 represents a group selected from among aryl groups of 6 to 15 carbon atoms, cycloalkyl groups of 6 to 15 carbon atoms, aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms.

[0068] According to one embodiment, the fat composition according to the invention comprises, relative to the total weight of the fat composition:

[0069] - from 70 to 98% by weight of base oil(s),

[0070] - 2 to 30% by weight of hydroxyamine-type thickener,

[0071] - possibly from 0.01 to 10% by weight of functional additive(s).

[0072] The invention also relates to the use of hydroxy-amines as a thickener in a grease composition, said hydroxy-amines being capable of being obtained by the RI reaction between at least one monoepoxy of formula (1) and at least one primary amine of formula (2),

[0073] Formulas (1) and (2) being defined as follows:

[0074] [Chem.l] R1

[0075] [Chem.2] tLN XSAR—

[0076] in which:

[0077] R1 represents a hydrogen atom or a group chosen from hydrocarbon groups possibly comprising one or more heteroatoms,

[0078] R2 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms,

[0079] R3 represents a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms.

[0080] The present invention makes it possible to synthesize hydroxy-amine type compounds, which can be used as a thickener for the preparation of lubricating grease.

[0081] Thus, the present invention makes it possible to do without the use of isocyanate for the preparation of thickener.

[0082] Furthermore, the present invention can be implemented using bio-based products, thereby reducing the environmental impact.

[0083] In the following text, the expressions "between ... and ...", "ranging from ... to ..." and "varying from ... to ..." are equivalent and are meant to mean that the limits are included, unless otherwise stated.

[0084] Unless otherwise indicated, quantities in a product are expressed in weight, relative to the total weight of the product. Detailed description

[0085] The present invention relates to a process for preparing a grease comprising a step of synthesizing a hydroxyamine including the reaction RI between at least one monoepoxy of formula (1) and at least one primary amine of formula (2) in order to obtain a hydroxyamine,

[0086] said RI reaction possibly being carried out in the presence of a base oil HB1,

[0087] the grease being formed (i) in situ as a result of the RI reaction or (ii) in a subsequent step to the RI reaction by mixing said hydroxyamine with a base oil HB2, HB2 being identical or different from the base oil HB1 possibly used in the RI reaction,

[0088] Formulas (1) and (2) being defined as follows:

[0089] [Chem.l] ~......XR:î

[0090] [Chem.2] 1LN R —

[0091] in which:

[0092] R1 represents a hydrogen atom or a group chosen from hydrocarbon groups possibly comprising one or more heteroatoms,

[0093] R2 represents a hydrogen atom or a group chosen from hydrocarbon groups possibly comprising one or more heteroatoms,

[0094] R3 represents a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms.

[0095] In the context of the present invention, a "hydrocarbon group" is a linear, branched or cyclic, saturated or unsaturated aliphatic group, or a aromatic group possibly substituted consisting of carbon and hydrogen atoms.

[0096] In the context of the present invention, a "hydrocarbon group comprising one or more heteroatoms" is a hydrocarbon group in which the carbon and hydrogen atoms are substituted by one or more heteroatoms.

[0097] Preferably, the heteroatoms can be oxygen atoms and / or nitrogen atoms.

[0098] In the context of the present invention, a "hydroxyamine" means a compound comprising at least one hydroxyl (-OH) group and at least one amine group. Hydroxyamines may comprise several hydroxyl groups and several amine groups. The amine groups may be primary, secondary, or tertiary. Advantageously, the hydroxyamines implemented in the invention comprise at least one secondary amine group.

[0099] According to a preferred embodiment, in formulas (1) and (2):

[0100] R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms, preferably R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms,

[0101] R2 represents a hydrogen atom,

[0102] R3 represents a group selected from alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups, preferably R3 represents a group selected from aryl groups of 6 to 15 carbon atoms, cycloalkyl groups of 6 to 15 carbon atoms, aminoalkyl groups of 2 to 15 carbon atoms and 1 to 6 nitrogen atoms.

[0103] In the context of the present invention, an "alkyl" group means an aliphatic, saturated, linear or branched hydrocarbon group consisting of carbon and hydrogen atoms.

[0104] In the context of the present invention, a "cycloalkyl" group means an aliphatic, saturated, cyclic hydrocarbon group, optionally substituted by one or more alkyl groups, consisting of carbon and hydrogen atoms.

[0105] In the context of the present invention, an "aminocycloalkyl" group means an aliphatic, saturated, cyclic hydrocarbon group, optionally substituted by one or more alkyl groups, consisting of carbon and hydrogen atoms and comprising at least one nitrogen atom.

[0106] In the context of the present invention, an "alkoxy" group means an aliphatic, saturated, linear or branched hydrocarbon group consisting of carbon and hydrogen atoms and comprising at least one ether -O- function.

[0107] In the context of the present invention, an "aryl" group means an unsubstituted aromatic hydrocarbon group consisting of carbon and hydrogen atoms.

[0108] In the context of the present invention, an "aminoaryl" group means an unsubstituted aromatic hydrocarbon group consisting of carbon and hydrogen atoms and comprising at least one nitrogen atom.

[0109] In the context of the present invention, an "aminoalkyl" group means an aliphatic, saturated, linear or branched hydrocarbon group consisting of carbon and hydrogen atoms and comprising at least one nitrogen atom.

[0110] In the context of the present invention, an "aminoalkoxy" group means a saturated, linear or branched aliphatic hydrocarbon group consisting of carbon and hydrogen atoms and comprising at least one ether (-O-) function and at least one nitrogen atom. An aminoalkoxy group may thus optionally comprise one or more primary amine functions and one or more ether functions.

[0111] In the context of the present invention, a “primary amine” is a compound comprising at least one primary amine function (-NH2).

[0112] In the context of the present invention, a "primary monoamine" is a compound comprising a single primary amine function (-NH2). A primary monoamine may optionally comprise, in addition to the single primary amine function, one or more secondary or tertiary amine functions.

[0113] In the context of the present invention, a "primary diamine" is a compound comprising exactly two primary amine (-NH2) functions. A primary diamine may optionally comprise, in addition to the two primary amine functions, one or more secondary or tertiary amine functions.

[0114] In the context of the present invention, a “monoepoxy” means a compound comprising a single epoxy function.

[0115] Advantageously, the amine of formula (2) implemented in the invention is a primary diamine. According to this embodiment, R3 is a group not comprising an -NH2 function (primary amine).

[0116] In the context of the present invention, a "grease" or a "grease composition" refers to a composition having an elastic modulus G' greater than the viscous modulus G". This relationship will typically be verified up to the threshold stress.

[0117] The elastic modulus and the viscous modulus can be measured for example at a frequency of 10 Hz.

[0118] The elastic and viscous moduli G' and G'' can be measured, for example, using a stress rheometer, by fixing a given temperature.

[0119] The synthesis reaction of hydroxyamine can be carried out with or without solvent.

[0120] When carried out without solvent, preferably the process for synthesizing hydroxyamine comprises:

[0121] a) the mixture of the monoepoxy of formula (1) and the amine of formula (2),

[0122] b) heating the mixture from step a) with stirring to a temperature going from 50°C to 250°C, preferably from 120 to 200°C to form hydroxyamine.

[0123] The step of forming the hydroxy-amine (RI type reaction) is preferably carried out at atmospheric pressure.

[0124] When implemented in the presence of a solvent, the solvent will preferably be chosen from the HB1 base oils.

[0125] Fat can be formed: i. in situ following the RI reaction carried out in an HB1 base oil or ii. in a subsequent step to the RI reaction by mixing the hydroxyamine obtained at the end of the RI reaction with a base oil HB2, HB2 being identical or different from HB1.

[0126] Thus, according to a first embodiment of the process of the invention, the grease is formed in situ during the synthesis of hydroxyamine. According to this embodiment, the process typically comprises:

[0127] a) the mixture of the monoepoxy of formula (1) and the amine of formula (2),

[0128] b) the mixture of the mixture from step a) and the HB1 base oil(s),

[0129] c) heating the mixture from step b) with stirring to a temperature above the melting point of urea,

[0130] d) cooling without stirring the reaction mixture to a temperature typically ranging from 20 to 25°C to form a urea-based grease.

[0131] More specifically, according to this first in situ embodiment, the fat preparation process may include:

[0132] a) the mixture of the monoepoxy of formula (1) and the amine of formula (2),

[0133] b) the mixture of the mixture from step a) and the HB 1 base oil(s),

[0134] c) heating the mixture from step b) with stirring at a temperature ranging from 50°C to 250°C, preferably from 120°C to 200°C, for a period ranging from 10 minutes to 72 hours,

[0135] d) cooling by stopping the stirring of the reaction mixture until a temperature of 20 to 25°C to form the grease.

[0136] Grease forms during cooling, particularly when the temperature of the medium becomes lower than the crystallization temperature of the hydroxyamines formed.

[0137] According to a second embodiment, the fat is formed in a second step, after the formation of the urea. According to this embodiment, the process typically comprises:

[0138] a) the mixture of the monoepoxy of formula (1) and the amine of formula (2),

[0139] b) heating the mixture from step a) while stirring in order to obtain hydroxy-amines, said step possibly being implemented in the presence of one or more HB1 base oils,

[0140] c) heating the HB2 base oil(s) under stirring typically to a temperature ranging from 50°C to 250°C, preferably from 120 to 190°C,

[0141] d) adding the hydroxyamines obtained at the end of step b) to the base oil or HB2 base oils of step c), with stirring until completely dissolved,

[0142] e) optionally further heating with stirring of the mixture from step b) to a temperature of 100 to 250°C, preferably 150 to 200°C,

[0143] f) maintaining the reaction medium until a homogeneous dispersion is obtained,

[0144] g) maintaining the homogeneous reaction medium from step f) for a duration ranging from 10 minutes to 5 hours,

[0145] h) cooling by stopping the stirring of the reaction medium from step g) to a temperature typically ranging from 20 to 25°C to form the fat.

[0146] Grease forms during cooling, particularly when the temperature of the medium becomes lower than the crystallization temperature of hydroxyamines.

[0147] During the synthesis reaction of the hydroxy-amine, the mixture of the monoepoxy of formula (1) and the amine of formula (2) can be heated to a temperature ranging from 50°C to 250°C, preferably from 120°C to 200°C.

[0148] By way of example, the reactants can be pre-mixed at a temperature of 50 to 120°C and then the mixture can be heated to a temperature of 120°C to 250°C, preferably 120 to 200°C.

[0149] The mixture can be heated for a period of 10 minutes to 72 hours, preferably 20 minutes to 48 hours.

[0150] The synthesis reaction of hydroxy-amine can be followed by differential scanning calorimetry (DSC).

[0151] The synthesis of hydroxyamines typically leads to a mixture of several compounds. Indeed, amines of formula (2) can react once or several times with monoepoxys of formula (1).

[0152] Typically, the synthesis of hydroxyamine leads to at least one compound corresponding to one of the formulas (3), (4), (5), (6) or (7):

[0153] [Chem.3] OH

[0154] [Chem.4] OH IT NTL

[0155] [Chem.5] OH OH i ..HH ..NH  , R' 'V "R '■] " TA 42 Jj RR

[0156] [Chem.6]

[0157] [Chem.7] OH OH ..HH A R" V' R R' R1

[0158] in which R1, R2 and R3 are as defined in the framework of formulas (1) and (2). Base oil(s)

[0159] Base oils can be chosen from among the base oils conventionally used in the field of lubricating oils, such as mineral, synthetic or natural, animal or vegetable oils or mixtures thereof.

[0160] This may be a mixture of several base oils, for example a mixture of two, three, or four base oils.

[0161] The base oils of the grease compositions considered according to the invention may in particular be oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in Table 1 below or their mixtures.

[0162] [Tables 1] Saturates content Sulfur content Viscosity index (VI) Group I Mineral oils <90% > 0.03% 80 <VI < 120 Groupement II Huiles hydrocraquées >90% <0.03% 80 <VI < 120 Groupement III Huiles hydrocraquées o u hydro-isomérisées >90% <0.03% >120 Group IV Polyalphaolefins (PAO) Group V Esters and other bases not included in groups I to IV

[0163] Mineral base oils include all types of base oils obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, desalpha removal, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0164] Mixtures of synthetic and mineral oils, which may be bio-based, may also be used.

[0165] Base oils can also be chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, polyalphaolefins (PAOs), and polyalkylene glycol (PAGs) obtained by polymerization or copolymerization of alkylene oxides comprising 2 to 8 carbon atoms, in particular 2 to 4 carbon atoms.

[0166] PAOs used as base oils are, for example, obtained from monomers comprising 4 to 32 carbon atoms, for example from octene or decene. The weight-average molecular weight of the PAO can vary quite widely. Preferably, the weight-average molecular weight of the PAO is less than 600 Da. The weight-average molecular weight of the PAO can also range from 100 to 600 Da, from 150 to 600 Da, or even from 200 to 600 Da.

[0167] When the reaction of the monoepoxy of formula (1) and the amine of formula (2) to form the hydroxy-amine is carried out in the presence of at least one base oil HB1, preferably the mass ratio base oil(s) / mixture {hydroxy-urethane and amine] ranges from 70 / 30 to 98 / 2, preferably from 80 / 20 to 95 / 5. Monoepoxy of formula (1)

[0168] The epoxy used in the invention is a mooepoxy and corresponds to formula (1):

[0169] [Chem.l] R1 "R?

[0170] in which:

[0171] R1 represents a hydrogen atom or a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms, preferably R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms,

[0172] R2 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms, preferably R2 represents a hydrogen atom.

[0173] According to one embodiment, the monoepoxy is glycidyl hexadecyl ether.

[0174] Epoxy compounds are commercially available. Primary amine of formula (2)

[0175] The primary amine used in the invention is a primary diamine and corresponds to formula (2):

[0176] [Chem.2] R—

[0177] wherein R3 represents a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R3 represents a group selected from alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups, preferably again R3 represents a group selected from aryl groups of 6 to 15 carbon atoms comprising at least one primary amine function, cycloalkyl groups of 6 to 15 carbon atoms comprising at least one primary amine function, or aminoalkyl groups of 2 to 15 carbon atoms and 1 to 6 nitrogen atoms and further comprising at least one primary amine function.

[0178] Preferably, the primary amine functions of the primary diamines implemented in the invention are such that said primary amine functions do not interact with each other. In particular, when the two primary amine functions are present on two substituents of a ring, then said substituents are advantageously located in meta or para positions relative to each other. This avoids interaction between the two primary amine functions.

[0179] According to one embodiment, the amine of formula (2) is chosen from 4,4-methylenedianiline, isophorone diamine, para-phenylenediamine, diaminodecane, ethylene diamine, para-xylene diamine, polyether diamine of formula H2N-CH2-CH2-O-CH2-CH2-O-CH2-CH2-NH2, cadaverine, or a diamine of formula (8):

[0180] [Chem. 8] / x. / x *■ y Y

[0181] Preferably, the amine of formula (2) is chosen from 4,4-methylenedianiline, isophorone diamine, or polyether diamine of formula H2N-CH2-CH2-O-CH2-CH2-O-CH2-CH2-NH2.

[0182] Amines of formula (2) are commercially available.

[0183] Advantageously, the molar ratio of amine of formula (2) / monoepoxy of formula (1) ranges from 0.1 to 2, preferably from 0.3 to 0.8.

[0184] According to one embodiment, the process comprises the reaction between a monoepoxy corresponding to formula (1) where preferably R1 represents a group selected from alkoxy groups having from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms and R2 represents a hydrogen atom and a primary diamine corresponding to formula (2) where R3 represents a group selected from aryl groups of 6 to 15 carbon atoms, cycloalkyl groups of 6 to 15 carbon atoms, aminoalkyl groups of 2 to 15 carbon atoms and from 1 to 6 nitrogen atoms, process in which the molar ratio primary diamine of formula (2) / monoepoxy of formula (1) goes from 0.1 to 2, preferably from 0.3 to 0.8. Hydroxy-amine

[0185] Typically, the hydroxyamine obtained according to the process of the invention will comprise a mixture of several hydroxyamine compounds.

[0186] The hydroxyamines synthesized in the process of the invention will advantageously comprise one or more secondary amine functions. Indeed, it is these secondary amine functions that will allow the formation of a network and therefore a fat.

[0187] Advantageously, at least one hydroxyamine compound will correspond to one of the formulas (3), (4), (5), (6) or (7):

[0188] [Chem.3]

[0189] [Chem.4] OH AH T. R*- Y iT NH2

[0190] [Chem.5] OH OH i .Mi  R'yx F?

[0191] [Chem.6]

[0192] [Chem.7] OH OH

[0193] in which:

[0194] R1, R2 and R3 are as defined in formulas (1) and (2), preferably:

[0195] R1 represents a group selected from among the alkoxy groups comprising from 2 to 16 carbon atoms and 1 to 8 oxygen atoms,

[0196] R2 represents a hydrogen atom,

[0197] R3 represents a group selected from among aryl groups of 6 to 15 carbon atoms, cycloalkyl groups of 6 to 15 carbon atoms, aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms.

[0198] The process of the invention can also be implemented by using a mixture of amines of different formulas (2) and / or a mixture of monoepoxy of different formulas (1). In this case, mixtures of different hydroxyamine compounds can be obtained. Grease according to the invention

[0199] The invention also relates to a fat composition.

[0200] The fat composition according to the invention comprises hydroxyamines as a thickener, advantageously hydroxyamines obtained according to the synthesis process described in the invention.

[0201] The grease composition according to the invention comprises: - at least one base oil, - a hydroxyamine-type thickener, - possibly one or more functional additives.

[0202] The grease composition according to the invention will thus typically be free of metallic salt type thickener or urea type thickener.

[0203] The hydroxyamines of the fat composition according to the invention are advantageously chosen from hydroxyamines of formula (3), hydroxyamines of formula (4), hydroxyamines of formula (5), hydroxyamines of formula (6), hydroxyamines of formula (7) or mixtures thereof:

[0204] [Chem.3] OH

[0205] [Chem.4] GH ■,.X HH . R" YY R5 NH2

[0206] [Chem.5] OH OH ...HR RV" "RYR" R' R1

[0207] [Chem.6] OH R" OH ,JNH A 1 RR R2

[0208] [Chem.7] OH QH R?

[0209] in which:

[0210] R1 represents a hydrogen atom or a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms, preferably again R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms,

[0211] R2 represents a hydrogen atom or a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R2 represents a hydrogen atom,

[0212] R3 represents a group selected from hydrocarbon groups possibly comprising one or more heteroatoms, preferably R3 represents a group selected from alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups, preferably again R3 represents a group selected from aryl groups of 6 to 15 carbon atoms, cycloalkyl groups of 6 to 15 carbon atoms, aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms.

[0213] The grease composition according to the invention advantageously comprises

[0214] - from 70 to 98% by weight of base oil(s),

[0215] - from 2 to 30% by weight of hydroxyamine according to the invention,

[0216] - possibly from 0.01 to 25% by weight of functional additive(s),

[0217] relative to the total weight of the fat composition.

[0218] According to one embodiment, the grease composition according to the invention further comprises at least one functional additive (different from the base oils and hydroxyamine), preferably selected from antioxidant additives, anti-corrosion additives, anti-foaming additives and mixtures thereof.

[0219] Typically, when present, these additional functional additives represent (in total) from 0.01 to 25% by weight, preferably from 0.5 to 20% by weight, of the total weight of the fat composition.

[0220] These additives can be introduced individually and / or in the form of a mixture.

[0221] The fat composition according to the invention may include at least one antioxidant additive. The antioxidant additive may be selected from phenolic or amino-type antioxidants.

[0222] Antioxidant additives may in particular be selected from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted with at least one C1-C12 alkyl group, N,N'-dialkyl-aryl-diamines and mixtures thereof.

[0223] Amino compounds are another class of antioxidant additives that can be used, possibly in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example, aromatic amines of the formula NR10RnR12 in which R10 represents an aliphatic or aromatic group, possibly substituted, R11 represents an aromatic group, possibly substituted, and R12 represents a hydrogen atom, an alkyl group, an aryl group, or a 13, 14, 13 group. formula RS(O)ZR in which R represents an alkylene group or an alkenylene group, R14 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

[0224] The grease composition according to the invention may further comprise at least one antifoaming agent.

[0225] The antifoaming agent may be chosen from silicones.

[0226] The grease composition according to the invention may comprise from 0.01 to 2% by mass or from 0.01 to 5% by mass, preferably from 0.1 to 1.5% by mass or from 0.1 to 2% by mass of antifoaming agent, relative to the total weight of the composition.

[0227] The invention also relates to the use of hydroxyamine as a thickener in a lubricating grease.

[0228] Hydroxyamines used as a thickener in a lubricating grease may correspond to one of the formulas (3), (4), (5), (6) or (7), the formulas (3), (4), (5), (6) or (7) being as defined above.

[0229] In particular, the hydroxyamine used as a thickener in a lubricating grease can be obtained by the RI reaction between at least one monoepoxy of formula (1) and at least one primary amine of formula (2), formulas (1) and (2) being as defined previously.

[0230] Advantageously, the RI reaction can be as defined previously within the framework of the process according to the invention. Applications

[0231] The grease composition according to the invention is preferably implemented in electric motors, in particular in electric motors of electric or hybrid vehicles.

[0232] An electric vehicle is a vehicle having an electric motor as its sole means of propulsion.

[0233] A hybrid vehicle is a vehicle comprising an electric motor and a combustion engine.

[0234] The invention also relates to a method of lubricating at least one component of an electric motor, preferably of an electric or hybrid vehicle, said method comprising bringing the component into contact with a grease according to the invention.

[0235] All the characteristics and preferences presented for the grease according to the invention apply to the lubrication process of the component of an electric motor according to the invention.

[0236] The invention will now be described by means of the following examples, given of course by way of illustration and not limitation of the invention. Examples

[0237] Example 1: Synthesis of fat comprising a hydroxyamine _ (HAI) as a thickener

[0238] In a first step, isophorone diamine (IPDA) is pre-mixed with glycidyl hexadecyl ether (GHE) at a temperature of 80°C.

[0239] In a second step, the mixture is heated to 160°C. The reaction is monitored by DSC. A mixture of hydroxyamines HAI is obtained.

[0240] In a third step, 9 parts of PAO8 oil (polyalphaolefin having a viscosity at 100°C of 8 cSt) for 1 part of HAÏ are added (overall mixture = 90% by weight of PAO8 oil + 10% by weight of hydroxy-amine HAÏ).

[0241] In a fourth step, the reaction medium is cooled to room temperature by stopping the stirring to form the fat.

[0242] Two IPDA / GHE molar ratios were tested: 1 / 2 and 1 / 3.

[0243] At the end of this example, a grease is obtained. The grease is based on a hydroxy-amine and exhibits the properties of table 2.

[0244] [Tables2] IPDA / GHE molar ratio Melting temperature (°C) Elastic modulus G' (Pa) Viscous modulus G'' (Pa) Yield stress (Pa) HAla 1 / 2 43 10500 1700 90 HAlb 1 / 3 42 1500 220 25

[0245] The properties of the fats are interesting, in particular thanks to relatively high G' and G'' moduli.

[0246] Example 2: Synthesis of a fat based on hydroxyamine (HA2)

[0247] In a first step, 4,4-methylenedianiline (MDA) is pre-mixed with glycidyl hexadecyl ether (GHE) at a temperature of 90°C.

[0248] In a second step, the mixture is heated to 160°C for 1. The reaction is monitored by DSC. Hydroxy-amine HA2 is obtained.

[0249] In a third step, 9 parts of PAO8 oil (polyalphaolefin having a viscosity at 100°C of 8 cSt) for 1 part of HA2 are added (overall mixture = 90% by weight of PAO8 oil + 10% by weight of hydroxy-amine HA2).

[0250] In a fourth step, the reaction medium is cooled to room temperature by stopping the stirring to form the fat.

[0251] Several MDA / GHE molar ratios were tested: 1 / 1, 1 / 2, 1 / 3, 1 / 4.

[0252] At the end of this example, a fat is obtained. The fat is based on hydroxy- amine as a thickener and exhibits the properties of Table 3.

[0253] [Tables3] Molar ratio MD A / GHE Elastic modulus G' (Pa) Viscous modulus G” (Pa) Yield stress (Pa) HA2a 1 / 1 175 45 10 HA2b 1 / 2 10000 1400 70 HA2c 1 / 3 32000 2200 250 HA2d 1 / 4 80 45 2

[0254] The highest performing greases are obtained when the amine / epoxy ratio is from 0.3 to 0.8.

Claims

Demands

1. A process for preparing a grease comprising a hydroxyamine synthesis step including the RI reaction between at least one monoepoxy of formula (1) and at least one primary amine of formula (2) to obtain a hydroxyamine, said RI reaction optionally being carried out in the presence of a base oil HB1, the grease being formed (i) in situ during the RI reaction or (ii) in a subsequent step to the RI reaction by mixing said hydroxyamines with a base oil HB2, HB2 being identical or different from the base oil HB1 optionally used in the RI reaction, formulas (1) and (2) being defined as follows: [Chem.1] 0 s \ RR [Chem.2] R— in which: R1 represents a hydrogen atom or a group chosen from among the hydrocarbon groups possibly comprising one or more heteroatoms, R2 represents a hydrogen atom or a group chosen from among the hydrocarbon groups possibly comprising one or more heteroatoms, R3 represents a group chosen from among the hydrocarbon groups possibly comprising one or more heteroatoms.

2. A method according to claim 1, wherein: R1 represents an alkyl group comprising from 1 to 12 carbon atoms or an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms,

3. R2 represents a hydrogen atom, R3 represents a group chosen from among the alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups. A process according to claim 1 or 2, wherein the synthesis of hydroxy-amine leads to at least one compound corresponding to one of the formulas (3), (4), (5), (6) or (7): [Chem. 3] [Chem.4] OH R' NH2 [Chem. 5] [Chem.6] QH [Chem.7] pH NH ..A. ? ' CR in which R1, R2 and R3 are as defined in one of claims 1 or 2.

4. A method according to any one of claims 1 to 3, wherein the amine of formula (2) is chosen from among the amines having exactly two primary amine functions.

5. A method according to any one of claims 1 to 4, wherein the amine of formula (2) is selected from: - dianiline-type compounds optionally comprising one or more substituents, - cyclohexyl-type compounds comprising at least two substituents having at least one primary amine function, said two substituents being in meta or para positions relative to each other, - mono-aromatic compounds comprising at least two substituents having at least one primary amine function, said two substituents being in para positions relative to each other, - alkylene diamine-type compounds, - polyether diamine-type compounds.

6. A method according to any one of claims 1 to 5, wherein the amine of formula (2) is selected from 4,4-methylenedianiline, isophorone diamine, para-phenylenediamine, diaminodecane, ethylene diamine, para-xylene diamine, polyether diamine of formula H2N-CH2-CH2-O-CH2-CH2-O-CH2-CH2-NH2, cadaverine, or a diamine of formula (8): [Chem. 8]

7. A method according to any one of claims 1 to 6, wherein the monoepoxy of formula (1) is selected from glycidyl hexadecyl ether.

8. A process according to any one of claims 1 to 7, wherein the RI reaction of monoepoxy and amine of formula (2) to form hydroxyamine is carried out under one or more of the following conditions: - a temperature from 50°C to 250°C, preferably from 120°C to 200°C, - a duration from 10 minutes to 48 hours, preferably from 20 minutes to 36 hours, - a molar ratio of amine of formula (2) / monoepoxy of formula (1) from 0.1 to 2, preferably from 0.3 to 0.

8.

9. A method according to any one of claims 1 to 8, wherein the RI reaction comprising the reaction between a monoepoxy corresponding to formula (1) and a primary amine corresponding to formula (2) is carried out with a molar ratio of amine of formula (2) / monoepoxy of formula (1) ranging from 0.1 to 2, preferably from 0.3 to 0.

8.

10. A process according to any one of claims 1 to 9, wherein the RI reaction comprising the reaction between a monoepoxy corresponding to formula (1) and a primary amine corresponding to formula (2) is carried out in the presence of at least one base oil HB1, preferably with a mass ratio base oil(s) HB1 / mixture {monoepoxy and amine] ranging from 70 / 30 to 98 / 2, preferably from 80 / 20 to 95 / 5.

11. A process according to any one of claims 1 to 10, wherein the synthesis of hydroxyamine leads to a mixture of several compounds, at least one of the compounds corresponding to one of the formulas (3), (4), (5), (6) or (7): [Chem. 3] Y" 'R R" NH-> [Chem.4] OH ÏV NH2 [Chem. 5] OH OH R 'y' R 'fÇ [Chem.6] Mi >. NH R • [Chem.7] OH R' HH ,.NH R' -

12. in which: R1 represents a group chosen from among the alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms, R2 represents a hydrogen atom, R3 represents a group chosen from among the aryl groups of 6 to 15 carbon atoms, the cycloalkyl groups of 6 to 15 carbon atoms, the aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms. Lubricating grease composition obtainable by the process according to any one of claims 1 to 11, said grease composition comprising at least a base oil and a hydroxyamine-type thickener.

13. Lubricating grease composition according to claim 12, wherein the hydroxyamine-type thickener comprises at least one compound corresponding to one of the formulas (3), (4), (5), (6) or (7): [Chem. 3] OH RY 'R' [Chem.4] OH YN H-. [Chem. 5] OH OH I r Y. . HH 3.NH ..A. RYR' Y'" R' [Chem.6] OH OH [Chem.7] OH OH xY YH v HH A , R" 'VY J if 1 RR in which: R1 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly including one or more heteroatoms, preferably R1 represents an alkyl group comprising from 1 to 12 carbon atoms or a group an alkoxy group comprising from 1 to 24 carbon atoms or an aryl group comprising from 6 to 10 carbon atoms, preferably R1 represents a group selected from alkoxy groups comprising from 2 to 16 carbon atoms and from 1 to 8 oxygen atoms, R2 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms, preferably R2 represents a hydrogen atom, R3 represents a group chosen from among the hydrocarbon groups possibly comprising one or more heteroatoms, preferably R3 represents a group chosen from among the alkyl, alkoxy, cycloalkyl, aryl, aminoaryl, aminocycloalkyl, aminoalkyl, or aminoalkoxy groups, preferably again R3 represents a group chosen from among the aryl groups of 6 to 15 carbon atoms, the cycloalkyl groups of 6 to 15 carbon atoms, the aminoalkyl groups of 2 to 15 carbon atoms and of 1 to 6 atoms.

14. A fat composition according to claim 12 or 13, comprising, relative to the total weight of the fat composition: - 70 to 98% by weight of base oil(s), - 2 to 30% by weight of hydroxyamine type thickener, - possibly 0.01 to 10% by weight of functional additive(s).

15. Use of hydroxyamines as a thickener in a grease composition, said hydroxyamines being capable of being obtained by the RI reaction between at least one monoepoxy of formula (1) and at least one primary amine of formula (2), formulas (1) and (2) being defined as follows: [Chem.1] Bone \ RR [Chem.2] r—mu in which: R1 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly comprising one or more heteroatoms, R2 represents a hydrogen atom or a group chosen from among hydrocarbon groups possibly containing one or more heteroatoms, R3 represents a group chosen from among the hydrocarbon groups possibly containing one or more heteroatoms.