Thermally associated exchangeable copolymers and compositions containing them

Abstract

The present invention relates to a comb copolymer A2 comprising at least two borate functional groups, the copolymer comprising a main chain and side chains, and at least a part of the side chains of the copolymer A2 is composed of oligomers. The present invention also relates to a composition obtained by mixing at least one polyglycol compound A1 and the copolymer A2. Depending on the ratio of the compounds A1 and A2 used, the composition exhibits very different rheological properties. The present invention also relates to a lubricant composition comprising such a mixture and at least one lubricating oil. The present invention also discloses the use of the composition for lubricating mechanical parts.

Description

Technical Field

[0001] The present invention relates to a comb copolymer A2 comprising at least two borate functional groups. The present invention also relates to a composition obtained by mixing at least one polydiol compound A1, in particular a polydiol copolymer A1, and at least one comb copolymer A2 comprising at least two borate functional groups. Depending on the ratio of compounds A1 and A2 used, such a composition exhibits very different rheological properties. The present invention also relates to a composition obtained by mixing at least one lubricating oil with such a polymer composition and to the use of such a composition for lubricating machine parts.

[0002] The present invention relates to the field of associative exchangeable polymers and to the field of lubricants. Prior art

[0003] Polymers with high molar masses are used in many areas, for example in the petroleum, paper, water treatment, mining, cosmetics and textile industries, as well as to increase the viscosity of solutions in all industrial technologies where thickening solutions are usually used.

[0004] In fact, these high molecular weight polymers show a significant disadvantage of irreversible degradation under mechanical stress, compared to the same polymers of smaller size. These shear stresses on polymers of high molar mass lead to the scission of macromolecular chains. The thickening properties of the polymer thus degraded decrease or disappear, and the viscosity of the solution containing it decreases irreversibly. This low shear strength leads to a deterioration of the properties of solutions based on polymers of high molar mass.

[0005] Applications WO2015 / 110642, WO2015 / 110643 and WO2016113229 disclose a composition obtained by mixing at least one copolymer A1 obtained by copolymerization of at least one monomer functionalized with a diol functional group and at least one compound A2 comprising at least two borate functional groups, in particular, compound A2 may be a copolymer comprising at least two borate functional groups. These compounds may associate to form a gel and exchange chemical bonds in a thermoreversible manner. These additives exhibit the advantage of reducing the viscosity drop of the solution containing them when the temperature increases. Depending on the ratio of compounds A1 and A2 used, these polymer compositions exhibit very different rheological properties. They may additionally contain exogenous compounds, which makes it possible to better control the association of the two compounds.

[0006] In particular, these polymer compositions can be added to lubricating oils to lubricate mechanical parts. These copolymers allow the formulation of lubricating compositions whose viscosity is better controlled than that of prior art lubricating compositions. In particular, when these copolymers are introduced into base oils, they tend to reduce the viscosity drop of the mixture when the temperature increases.

[0007] Lubricating compositions are compositions applied to the surfaces of moving parts, in particular between metal surfaces. They make it possible to reduce friction and wear between two parts that are in contact and moving with each other. They also serve to dissipate a portion of the heat energy generated by this friction. Lubricating compositions form a protective film between the surfaces of the parts to which they are applied.

[0008] Compositions for lubricating mechanical parts generally consist of base oils and additives. Base oils, especially those of petroleum or synthetic origin, exhibit changes in viscosity when the temperature changes.

[0009] This is because, when the temperature of the base oil increases, its viscosity decreases, and when the temperature of the base oil decreases, its viscosity increases. In fact, under hydrodynamic lubrication conditions, the thickness of the protective film is proportional to the viscosity and therefore also depends on the temperature. If the thickness of the protective film remains substantially constant, the composition exhibits good lubrication properties regardless of the condition of the lubricant and the length of time it is used.

[0010] In an internal combustion engine, the lubricating composition may be subjected to external or internal temperature changes. External temperature changes are caused by changes in the temperature of the ambient air, such as the temperature change between summer and winter. Internal temperature changes are caused by the operation of the engine. The temperature during the start-up phase of the engine (especially in cold weather) is lower than the temperature in continuous use. Therefore, the thickness of the protective film can vary under these different circumstances.

[0011] Therefore, it is necessary to provide a lubricating composition having good lubricating properties, the viscosity of which is not significantly affected by temperature changes.

[0012] It is known to add viscosity modifiers which improve the viscosity of lubricating compositions. The function of these additives is to modify the rheological behavior of the lubricating composition. They enable greater stability of the viscosity to be obtained within the temperature range in which the lubricating composition is used. For example, these additives limit the decrease in viscosity of the lubricating composition at rising temperatures, while limiting the increase in viscosity under cold conditions.

[0013] Viscosity improvers (or viscosity index improvers) ensure good lubrication by limiting the effect on viscosity in cold conditions and ensuring minimum film thickness in hot conditions. Currently used viscosity improvers are polymers such as olefin copolymers (OCPs) and polyalkyl methacrylates (PAMs). Generally, the higher their molecular weight, the greater the contribution of these polymers to viscosity control.

[0014] However, polymers of high molar mass show the disadvantage of low resistance to permanent shear compared to polymers of the same substance and the same structure but smaller in size.

[0015] In practice, lubricating compositions are subject to high shear stresses, in particular in internal combustion engines, where the spacing of moving surfaces is small and the pressures exerted on the parts are high. These shear stresses on polymers of high molar mass lead to the breaking of macromolecular chains. The thickening properties of the polymers thus degraded decrease, and the viscosity irreversibly decreases. This low resistance to permanent shearing therefore leads to a deterioration in the lubricating properties of the lubricating composition.

[0016] Finally, attempts have been made to develop compositions that exhibit improved stability towards oxidation, in particular improved resistance to free radical oxidation.

[0017] The document PJM Stails et al., JACS, 135, 31, 12 / 03 / 2013, 11421-11424, describes a free-radical method of the RAFT type for the synthesis of comb copolymers by bromination of acrylic acid monomers and a post-functionalization stage.

[0018] Document FR 3 040 172 describes compositions of polymers crosslinkable by means of exchangeable bonds by metathesis reactions of boric acid esters and boric acid diesters as crosslinking agents.

[0019] In applications WO2015 / 110642, WO2015 / 110643 and WO2016113229, it is pointed out that the random diol copolymer A1 is a comb-type copolymer, that is, the copolymer has a main chain (also called a backbone) and hydrocarbon side chains extending from both sides of the main chain, and the side chains are optionally hydroxylated. It can be seen that the side chains of these copolymers in the prior art are not polymers or oligomers, so these copolymers are not comb-type copolymers in the usual sense of the art (IUPAC Commission on Macromolecular Nomenclature, Glossary of basic terms in polymerscience, 1996 Recommendations, website https: / / www.gfp.asso.fr / wp-content / uploads / glossaire.pdf). In practice, these copolymers are linear copolymers whose non-polymeric hydrocarbon side chains have an average length of between 8 and 20 carbon atoms.

[0020] The compositions described in applications WO2015 / 110642, WO2015 / 110643 and WO2016113229 exhibit very advantageous properties due to their ability to form thermoreversible associations. However, it is desirable to further improve these properties; in particular, attempts have been made to reduce the sensitivity of the viscosity of the composition with respect to temperature, in order to provide compositions that exhibit better viscosity stability between high and low temperatures. It is also attempted to provide compositions that exhibit a greater range of viscosity adjustment.

[0021] Furthermore, it has been found that under certain conditions, in particular at high temperatures, the associative behavior of these copolymers is reduced. In particular, a decrease in the viscosity index and a poorer resistance to cycling (defined as the successive rise and fall in temperature as observed in an engine) have been observed for lubricating compositions containing them, leading to a loss of lubrication properties over time.

[0022] The Applicant Companies therefore set themselves the goal of preparing novel copolymers which exhibit improved properties relative to the copolymers of the prior art.

[0023] This object is achieved by novel rheological additives which can associate, possibly form gels and exchange in a thermoreversible manner. Unlike base oils which thin at elevated temperatures, the additives of the invention exhibit the advantage of thickening the medium in which they are dispersed at elevated temperatures and retain this advantage at elevated temperatures, for example up to 150° C. These additives comprise a polyglycol compound A1 and a comb copolymer A2 comprising at least two borate functional groups, at least one part of whose side chains is of oligomeric or polymeric type. These additives allow a greater range of adjustment of the viscosity as a function of temperature. The lubricating compositions comprising them have a reduced viscosity sensitivity with respect to temperature and a higher viscosity stability with respect to temperature variations. This feature results from the combined use of two specific compounds, one of which is a comb copolymer with borate functional groups and optionally styrene functional groups and the other is a compound comprising a glycol functional group.

[0024] By means of the composition of the invention, it is possible to provide a lubricating composition which has good lubricating properties during the engine start-up phase (cold phase) and good lubricating properties when the engine is running at its operating temperature (hot phase). Summary of the invention

[0025] The present invention provides a comb copolymer A2 comprising at least two borate functional groups, said copolymer comprising a main chain and side chains, at least a portion of the side chains of the copolymer A2 being composed of oligomers.

[0026] According to a preferred embodiment, in the comb copolymer A2 at least a portion of the side chains consists of oligomers comprising more than 30 carbon atoms, preferably at least 50 carbon atoms, more preferably at least 70 carbon atoms.

[0027] According to yet another preferred embodiment, the side chains consisting of oligomers comprising more than 30 carbon atoms represent from 3% to 95% by weight, preferably from 15% to 95% by weight, relative to the total weight of copolymer A2.

[0028] According to a preferred embodiment, at least a part of the side chains of the copolymer A2 is composed of oligomers having a degree of polymerization of 5 to 1000, preferably 5 to 500, more preferably 5 to 200.

[0029] According to a preferred embodiment, the side chains consisting of oligomers represent 3% to 95% by weight, preferably 15% to 95% by weight, relative to the total weight of copolymer A2.

[0030] According to a preferred embodiment, at least a portion of the side chains of the copolymer A2 are constituted by oligomers O1 comprising polyolefin segments.

[0031] According to a preferred embodiment, the side chains of the copolymer A2 composed of the oligomer O1 comprise polyolefin segments having from 30 to 500 carbon atoms, preferably from 50 to 400 carbon atoms, even more preferably from 50 to 200 carbon atoms.

[0032] According to a preferred embodiment, the side chains comprising polyolefin segments represent 3% to 85% by weight, preferably 15% to 70% by weight, relative to the total weight of copolymer A2.

[0033] According to a preferred embodiment, the oligomer O1 is present in the copolymer A2 in the form of repeating units corresponding to one or more than one monomer M6 of the general formula (IX):

[0034]

[0035] in:

[0036] Q1 is selected from -H, -CH3 and -CH2-CH3;

[0037] Q2 is selected from the group consisting of -Q', -O-Q', -C(O)-O-Q', -OC(O)-Q', -S-(CH2)2-C(O)-O-Q', -S-Q', -N(H)-C(O)-Q' and C(O)-N(H)-Q', wherein Q' is a polyolefin,

[0038] n represents an integer from 0 to 1,

[0039] A represents a group selected from -A1-, -O-(-A2-O-) n' -A1-, -C(O)-O-(-A2-O-) n' -A1-、-OC(O)-(-A2-O-) n' -A1-、-S-(-A2-O-) n' -A1-, -N(H)-C(O)-(-A2-O-) n' -A1- and -C(O)-N(H)-(-A2-O-) n' -A1- divalent group, wherein

[0040] A1 is selected from C1 to C 30 Alkyl, C6 to C 30 Aryl or C6 to C 30 A divalent aralkyl group,

[0041] A2 is a divalent group selected from C2 to C4 alkyl groups,

[0042] n' is an integer, and n' represents 0 or 1.

[0043] According to a preferred embodiment, when the side chains of copolymer A2 are composed of oligomers O1 comprising polyolefin fragments having 30 to 105 carbon atoms, the repeating units of copolymer A2 contain greater than 5 mol % of monomers M6 of general formula (IX), preferably greater than 6 mol % of monomers M6 of general formula (IX), and even more preferably greater than 6.5 mol % of monomers M6 of general formula (IX).

[0044] According to a preferred embodiment, the comb copolymer A2 comprises at least repeating units of the monomer M4 corresponding to the formula (IV):

[0045]

[0046] in:

[0047] -t is an integer equal to 0 or 1;

[0048] -u is an integer equal to 0 or 1;

[0049] -M and R8 are divalent linking groups, which are the same or different and are selected from C6 to C 18 Aryl, C7 to C 24 Arylalkyl and C2 to C 24 Preferably, M is C6 to C 18 Aryl, R8 is C7 to C 24 Aralkyl;

[0050] -X is a functional group selected from -OC(O)-, -C(O)-O-, -C(O)-N(H)-, -N(H)-C(O)-, -S-, -N(H)-, -N(R'4)-, and -O-, wherein R'4 is a hydrocarbon chain containing 1 to 15 carbon atoms;

[0051] -R9 is selected from -H, -CH3 and -CH2-CH3;

[0052] -R 10 and R 11 identical or different, it represents a group chosen from a hydrogen atom or a hydrocarbon radical containing 1 to 30 carbon atoms, optionally substituted by one or more than one group chosen from: a hydroxyl group or an -OJ or -C(O)-OJ group, in which J is a hydrocarbon radical containing 1 to 24 carbon atoms;

[0053] According to a preferred embodiment, the comb copolymer A2 comprises at least repeating units of the monomer M5 corresponding to the general formula (V):

[0054]

[0055] in:

[0056] -R 12 is selected from -H, -CH3 and -CH2-CH3,

[0057] -R 13 Selected from C6 to C 18 Aryl and R' 13 、-C(O)-OR' 13 、-OR' 13 、-SR' 13 and -C(O)-N(H)-R' 13 C6 to C 18 Aryl, where R' 13 C1 to C 30 alkyl.

[0058] According to a preferred embodiment, the comb copolymer A2 comprises repeating units corresponding to at least one monomer M3 of the general formula (X):

[0059]

[0060] in:

[0061] - Z1, Z2 and Z3 are the same or different and represent a group selected from hydrogen atoms, C1 to C 12 alkyl or -OZ' or -C(O)-O-Z' group, wherein Z' is C1 to C 12 alkyl.

[0062] According to a further preferred embodiment of the comb copolymer A2, the monomer M3 is styrene.

[0063] According to a preferred embodiment of the comb copolymer A2, the repeating unit corresponding to the monomer of formula (X) is 2 mol% to 50 mol% relative to the total moles of the monomers constituting the copolymer A2.

[0064] According to a preferred embodiment, the repeating unit corresponding to the monomer M5 is 10 mol% to 90 mol%, preferably 30 mol% to 80 mol%, relative to the total moles of the monomers constituting the copolymer A2.

[0065] According to a preferred embodiment, the repeating unit corresponding to the monomer M4 is 1 mol% to 50 mol%, preferably 5 mol% to 30 mol%, relative to the total moles of the monomers constituting the copolymer A2.

[0066] According to one preferred embodiment, the degree of branching of copolymer A2 is between 0.1 mol % and 10 mol %. The degree of branching is calculated by taking into account only oligomeric side chains comprising more than 30 carbon atoms.

[0067] Preferably, the degree of branching of copolymer A2 is from 0.5 to 5 mol % when the oligomer chain is an olefin having more than 100 carbon atoms and from 5 to 10 mol % when the oligomer chain is an olefin having 30 to 100 carbon atoms.

[0068] According to a preferred embodiment, the comb copolymer A2 comprises non-oligomeric side chains whose average length is from 1 to 10 carbon atoms, preferably from 3 to 8 carbon atoms.

[0069] According to a preferred embodiment, the number average degree of polymerization of the main chain of the comb copolymer A2 is from 40 to 2000, preferably from 40 to 1000.

[0070] According to a preferred embodiment, the number average degree of polymerization of the oligomeric side chains of the comb copolymer A2 is from 5 to 1000, preferably from 5 to 500, even more preferably from 5 to 200.

[0071] Another subject of the present invention is a composition obtained by mixing at least the following substances:

[0072] - polyglycol compound A1,

[0073] - the copolymer A2 defined in detail above and below.

[0074] According to a preferred embodiment, the polyglycol compound A1 is a comb copolymer.

[0075] According to a preferred embodiment, the polyglycol compound A1 is a copolymer obtained by copolymerizing the following substances:

[0076] At least one first monomer M1 having the general formula (I):

[0077]

[0078] in:

[0079] -R1 is selected from -H, -CH3 and -CH2-CH3;

[0080] -y is an integer equal to 0 or 1;

[0081] -Y represents a group consisting of C1 to C 20 a divalent linking group of an alkyl chain, which optionally comprises one or more than one ether-O-bridge;

[0082] - X1 and X2 are the same or different and are selected from hydrogen, tetrahydropyranyl, methoxymethyl, tert-butyl, benzyl, trimethylsilyl and tert-butyldimethylsilyl;

[0083] or

[0084] X1 and X2 form a bridge of the following formula with the oxygen atom:

[0085]

[0086] in:

[0087] -asterisk ( * ) represents a bond to an oxygen atom,

[0088] - R'2 and R"2 are the same or different and are selected from hydrogen and C1 to C 11 Alkyl, preferably methyl;

[0089] or

[0090] X1 and X2 form a boric acid ester with the oxygen atom:

[0091]

[0092] in:

[0093] -asterisk ( * ) represents a bond to an oxygen atom,

[0094] -R"'2 is selected from C6 to C 30 Aryl, C7 to C 30 Arylalkyl and C2 to C 30 Alkyl, preferably C6 to C 18 Aryl;

[0095] At least one second monomer M2 having the general formula (II):

[0096]

[0097] in:

[0098] R2 is selected from -H, -CH3 and -CH2-CH3;

[0099] R3 is selected from -C(O)-O-R'3; -O-R'3; -S-R'3 and -C(O)-N(H)-R'3, wherein R'3 is C1 to C 30 alkyl.

[0100] According to yet another preferred embodiment, the monomer M1 is selected from monomers of formula (Ia):

[0101]

[0102] Here, x is an integer of 1 to 18, preferably 2 to 18.

[0103] According to yet another preferred embodiment, the polyglycol copolymer A1 comprises repeating units corresponding to at least one monomer M3 of the general formula (X):

[0104]

[0105] in:

[0106] - Z1, Z2 and Z3 are the same or different and represent a hydrogen atom, a C1 to C 12 alkyl or -OZ' or -C(O)-O-Z' group, wherein Z' is C1 to C 12 alkyl.

[0107] According to a preferred embodiment, the content of the copolymer compound A1 is 0.1% to 50% by weight relative to the total weight of the composition.

[0108] According to a preferred embodiment, the content of copolymer A2 is from 0.1% to 50% by weight relative to the total weight of the composition.

[0109] According to a preferred embodiment, the weight ratio of copolymer A1 to compound A2 (A1 / A2 ratio) is 0.005 to 200, preferably 0.05 to 20, and more preferably 0.1 to 10.

[0110] Another subject of the present invention is a lubricating composition obtained by mixing at least:

[0111] - Lubricating oil, and

[0112] - A composition as defined in detail above and below. DETAILED DESCRIPTION

[0113] The expression "consisting essentially of" followed by one or more features means that in addition to the components or phases explicitly listed, components or phases may be included in the methods or materials of the present invention that do not significantly change the nature and characteristics of the present invention.

[0114] Unless expressly stated otherwise, "between X and Y" includes the end values. Therefore, this expression indicates that the target interval includes the values ​​X, Y and all values ​​from X to Y.

[0115] definition :

[0116] "Oligomer" is understood to refer to a macromolecule consisting of a limited number of repeating units. These repeating units can be all the same, or the oligomer can contain different repeating units. Typically, an oligomer comprises 2 to 1000 repeating units. Most commonly, an oligomer is produced by the polymerization or copolymerization of a limited number of monomers. An oligomer comprises a main chain and may comprise side chains, also referred to as pendant chains.

[0117] The main chain of a polymer or oligomer is a linear chain on which all other chains can be considered as side chains. When several chains can be considered as main chains, the main chain that gives the simplest representation of the molecule is the one specified. The term "main chain" within the meaning of the present invention does not necessarily mean that the chain length of the main chain is greater than the chain length of the side chains.

[0118] The side chain is a substituent of the macromolecular chain. The substituent can be a low molecular weight molecule, oligomer or polymer. Preferably, according to the present invention, the oligomer side chain comprises a series of at least 30 carbon atoms, preferably at least 50 carbon atoms, more preferably at least 70 carbon atoms.

[0119] "Copolymer" is understood to mean a linear or branched oligomer or macromolecule having a sequence consisting of several repeating units (or monomer motifs), wherein at least two units have different chemical structures.

[0120] "Monomeric moiety" or "monomer" is understood to mean a molecule that can be converted into an oligomer or macromolecule by combining with itself or with other molecules of the same type. A monomer represents the smallest building block, the repetition of which gives rise to an oligomer or macromolecule.

[0121] "Comb polymer", also referred to as branched copolymer, is understood to refer to a polymer having a main chain and at least one side chain or pendant chain connected to the main chain at a point between the two ends of the main chain (called a branching point). Unlike linear polymers comprising non-polymeric side groups or pendant groups, the side chains of comb polymers are oligomers, polymers or copolymers. Preferably, according to the present invention, the comb polymer comprises at least two, preferably at least three side chains or pendant chains. The degree of branching within the meaning of the present invention means the branching of oligomer side chains with more than 30 carbon atoms.

[0122] "Random copolymer" is understood to mean an oligomer or macromolecule in which the sequential distribution of monomer units obeys known statistical laws. For example, when a copolymer is formed from monomer units, the copolymer is random and its distribution is Markovian. A diagram of a random polymer (P1) is shown in FIG. Figure 1 The distribution of monomer units in the polymer chain depends on the reactivity of the polymerizable functional groups of the monomers and the relative concentration of the monomers.

[0123] "Block copolymer" is understood to mean an oligomer or macromolecule comprising one or more than one block or formed by blocks. "Block" means a part of a copolymer which comprises several identical or different monomer units and has at least one distinctive structural or configurational feature which allows it to be distinguished from adjacent parts. The diagram of block polymer (P3) is shown in Figure 1 shown.

[0124] "Gradient copolymer" means a copolymer of at least two monomer units of different structures, wherein the monomer composition gradually changes along the polymer chain, thereby gradually transitioning from one end of the polymer chain rich in one monomer unit to the other end rich in another comonomer. The schematic diagram of the gradient polymer (P2) is as follows Figure 1 shown.

[0125] Comb copolymers containing at least two borate functional groups of the present invention are random copolymers or gradient copolymers. They can show a gradient distribution of some monomers and a statistical or virtual statistical distribution of other monomers. They are different from block copolymers.

[0126] "Copolymerization" is understood to mean a process by which a mixture of at least two monomer units having different chemical structures can be converted into oligomers or copolymers.

[0127] Polyolefins are known to those skilled in the art. They can be obtained by polymerizing olefins and / or dienes composed of carbon and hydrogen, for example C2 to C 10 Olefins such as ethylene, propylene, n-butene, isobutene, cyclobutene, cycloheptene, cyclooctene or norbornene, and / or C4 to C 10 Diolefins, such as butadiene, isoprene, cyclooctadiene or norbornadiene. According to the present invention, the following are included in the definition of polyolefins: hydrogenated polyolefins and hydrogenated poly(diolefins), partially or fully hydrogenated olefins, polyolefins, hydrogenated polyolefins and hydrogenated polyolefin-co-polyolefin copolymers.

[0128] In the context of this patent application, "B" denotes a boron atom.

[0129] “C i To Cj "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing i to j carbon atoms. For example, "C1 to C 10 "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing from 1 to 10 carbon atoms.

[0130] “C x To C y "Aryl" is understood to mean a functional group derived from an aromatic compound containing x to y carbon atoms. The functional group may be monocyclic or polycyclic. For example, C6 to C 18 Aryl groups may be phenyl, naphthyl, anthracenyl, phenanthrenyl and naphthacene.

[0131] “C x To C y "Alkenyl" is understood to mean a linear or branched hydrocarbon chain comprising at least one unsaturated bond, preferably a carbon-carbon double bond, and comprising x to y carbon atoms.

[0132] “C x To C y "Arylalkyl" is understood to mean an aromatic compound substituted by at least one linear or branched alkyl chain, preferably a monocyclic aromatic compound, the total number of carbon atoms of the aromatic ring and its substituents being x to y carbon atoms. For example, C7 to C 18 The aralkyl group may be selected from benzyl, tolyl and xylyl.

[0133] "C substituted by Y group x To C y The term "aryl" is understood to mean an aromatic compound containing x to y carbon atoms, preferably a monocyclic aromatic compound, at least one carbon atom of the aromatic ring of which is substituted by a Y group.

[0134] "Halo" or "halogen" is understood to mean a halogen atom selected from chlorine, bromine, fluorine and iodine.

[0135] In the specification, when it is stated that a copolymer "comprises the monomers corresponding to M i repeating unit”, this means that the copolymer can be directly composed of monomer M i The copolymerization of i indicates the parameters that identify the monomers shown below and other comonomers, and the copolymer can also be made of monomers other than M. i It is obtained by copolymerization with monomers other than M and then undergoing a chemical conversion stage, so the structural units it contains are the same as those obtained by monomer M. iFor example, a monomer having an acid functional group, such as acrylic acid or methacrylic acid, can first be copolymerized with other monomers to form a copolymer, and then all or part of the acid functional groups are converted by any reaction, such as by esterification with an alkanol or amidation with an alkylamine. A copolymer containing repeating units corresponding to the alkyl acrylate or alkyl acrylamide monomer will then be obtained.

[0136] Comb-type copolymers with borate functional groups A2

[0137] The comb-type copolymer A2 comprising at least two borate functional groups comprises a main chain to which side chains are attached, and at least a part of the side chains of the copolymer A2 is constituted by oligomers.

[0138] The side chains of the comb copolymer A2 according to the invention differ from the side chains of the copolymers of the prior art comprising at least two borate functional groups in that at least a portion of the side chains consists of oligomers.

[0139] "Side chains consisting of oligomers" are understood to mean that at least a portion of the side chains is an oligomer of one or more than one monomer. At least it is not excluded that the side chains include other functional groups, such as a functional group or a series of functional groups connecting the side chains to the main chain.

[0140] Side chain of copolymer A2

[0141] The side chains of the copolymer A2 composed of oligomers exhibit a degree of polymerization which is different from zero, unlike the side chains of copolymers of the same type known from the prior art.

[0142] Preferably, the side chains consisting of oligomers represent 3% to 95% by weight, preferably 15% to 95% by weight, more preferably 20% to 95% by weight, relative to the total weight of copolymer A2.

[0143] Preferably, at least a portion of the side chains of copolymer A2 consist of oligomers comprising more than 30 carbon atoms, preferably at least 50 carbon atoms, more preferably at least 70 carbon atoms.

[0144] Preferably, the side chains consisting of oligomers comprising more than 30 carbon atoms represent 3% to 95% by weight, preferably 15% to 95% by weight, more preferably 20% to 95% by weight, relative to the total weight of copolymer A2.

[0145] Preferably, the degree of polymerization of at least a part of the side chains of the copolymer A2 composed of the oligomer is 5 to 1,000, preferably 5 to 500, and more preferably 5 to 200.

[0146] More preferably, the side chains consisting of oligomers having a degree of polymerization of 5 to 1000 represent 3 to 95% by weight, preferably 15 to 95% by weight, more preferably 20 to 95% by weight, relative to the total weight of the copolymer A2.

[0147] The oligomer side chains of the copolymer A2 may all be of the same kind or of different kinds.

[0148] The copolymer A2 may contain oligomeric side chains and side chains which are not oligomeric.

[0149] Preferably, the side chains of copolymer A2 which are not oligomeric compounds are 5 to 97 wt %, preferably 5 to 85 wt %, more preferably 5 to 80 wt %, more preferably 5 to 75 wt %, relative to the total weight of copolymer A2.

[0150] According to a first alternative form, at least part of the side chains of the copolymer A2 are constituted by oligomers O1 comprising polyolefin segments. The polyolefin segments may be obtained from polyolefin macromonomers or from functionalized monomers onto which polyolefin functional groups are grafted.

[0151] Preferably, the side chains comprising polyolefin segments represent 10% to 50% by weight, preferably 10% to 40% by weight, relative to the total weight of copolymer A2.

[0152] For example, the side chain comprising a polyolefin segment may be composed of repeating units corresponding to the monomer M6 of the general formula (IX) derived from a polyolefin.

[0153] According to another alternative form, at least part of the side chains of the copolymer A2 are constituted by an oligomer O2 comprising recurring units corresponding to a monomer chosen from the monomers M5 of general formula (V).

[0154] For example, according to this alternative form, at least part of the side chains of the copolymer A2 is constituted by an oligomer O2 comprising repeating units corresponding to monomers selected from:

[0155] - a monomer M4 having the general formula (IV),

[0156] - a monomer M5 having the general formula (V).

[0157] The copolymer A2 may contain two side chains of oligomer O1 type comprising polyolefin segments and oligomer O2 comprising recurring units corresponding to monomers selected from the group consisting of monomers M5 of general formula (V).

[0158] According to a preferred embodiment, when part of the side chains of copolymer A2 are composed of oligomers comprising repeating units corresponding to monomers M4 and / or M5, the degree of polymerization of these oligomers is 5 to 500, preferably 10 to 400, more preferably 20 to 200.

[0159] Main chain of copolymer A2

[0160] The main chain of the comb copolymer A2 preferably comprises repeating units which correspond to the monomer M4 of the general formula (IV).

[0161] The main chain of the comb copolymer A2 may comprise repeating units corresponding to the monomer M5 of the general formula (V).

[0162] Preferably, the main chain of the comb copolymer A2 comprises recurring units corresponding to at least one monomer M3 of the general formula (X) defined above. According to this alternative, the other monomers participating in the construction of the comb copolymer A2 must be compatible with the copolymerization of the monomers M3.

[0163] Copolymer A2 may be a random copolymer or a gradient copolymer.

[0164] Advantageously, the comb copolymer A2 is obtained directly or indirectly from the (co)polymerization of at least one monomer M4 having borate functionality, which is incorporated into the main chain or into the side chains of the copolymer A2, or into both.

[0165] "Directly or indirectly obtained" is understood to mean that the process for preparing the copolymer may comprise one or more than one different copolymerization stage, for example a deprotection stage.

[0166] Throughout the specification, the following expressions may be used interchangeably in an equivalent manner: "Copolymer A2 is obtained directly or indirectly by copolymerization" and "Copolymer A2 is obtained by copolymerization".

[0167] Distribution of monomers in the main chain and side chains

[0168] Monomers M4, M5 and M3 may be present in the main chain and / or in the side chain. In the side chain, they are present in the form of oligomers. Optionally, other monomers may be present in the main chain and / or in the side chain.

[0169] When the monomers M4, M5 and / or M3 are introduced into the main chain of the copolymer A2 according to the invention, the chains of the monomers M4, M5 and M3 form the non-oligomeric side chains of these polymers.

[0170] The comb copolymer A2 comprises non-oligomeric side chains, preferably having an average length of 1 to 10 carbon atoms, preferably 3 to 8 carbon atoms.

[0171] When the comb copolymer A2 comprises oligomeric side chains composed of monomers M4 or monomers M5, these monomers preferably have an average length of 1 to 10 carbon atoms.

[0172] The "average length" is understood to mean the average length of the alkyl segments of the side chains of the monomers M4 of formula (IV) and M5 of formula (V) which participate in the formation of the copolymer A2. When calculating the average length of the side chains of the comb copolymer A2, side chains resulting from styrene monomers are not taken into account. A person skilled in the art knows how to obtain this average length by appropriate selection of the types and proportions of the monomers that constitute the borate copolymer.

[0173] Unless otherwise indicated, the preferences expressed below for the selection of monomers M4, M5 and M3 are valid when they are present in the form of repeating units in the main chain and when they are present in the side chains.

[0174] Monomer M4 of formula (IV)

[0175] Monomer M4 of borate copolymer compound A2 has the general formula (IV):

[0176]

[0177] in:

[0178] -t is an integer equal to 0 or 1;

[0179] -u is an integer equal to 0 or 1;

[0180] -M and R8 are divalent linking groups, which are the same or different and are selected from C6 to C 18 Aryl, C7 to C 24 Arylalkyl and C1 to C 24 Preferably, M is C6 to C 18 Aryl, R8 is C7 to C 24 Aralkyl;

[0181] -X is a functional group selected from -OC(O)-, -C(O)-O-, -C(O)-N(H)-, -N(H)-C(O)-, -S-, -N(H)-, -N(R'4)-, and -O-, wherein R'4 is a hydrocarbon chain containing 1 to 15 carbon atoms;

[0182] -R9 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0183] -R 10 and R 11The same or different, which are selected from a hydrogen atom or a hydrocarbon group containing 1 to 30 carbon atoms, preferably 4 to 18 carbon atoms, more preferably 6 to 14 carbon atoms, the hydrocarbon group is optionally substituted by one or more than one group selected from the following: hydroxyl or -OJ or -C(O)-OJ groups, wherein J is a hydrocarbon group containing 1 to 24 carbon atoms.

[0184] "C1 to C 24 "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing from 1 to 24 carbon atoms. Preferably, the hydrocarbon chain is linear. Preferably, the hydrocarbon chain contains from 6 to 16 carbon atoms.

[0185] "Hydrocarbon chain comprising 1 to 15 carbon atoms" is understood to mean a linear or branched alkyl or alkenyl group comprising 1 to 15 carbon atoms. Preferably, the hydrocarbon chain is a linear alkyl group. Preferably, it comprises 1 to 8 carbon atoms.

[0186] “Hydrocarbon radical containing 1 to 30 carbon atoms” is understood to mean a linear, branched or cyclic alkyl radical containing 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl radical containing 2 to 30 carbon atoms, an aryl radical containing 6 to 30 carbon atoms or an aralkyl radical containing 7 to 30 carbon atoms.

[0187] "Hydrocarbon radical containing 1 to 24 carbon atoms" is understood to mean a linear, branched alkyl radical containing 1 to 24 carbon atoms, a linear, branched alkenyl radical containing 2 to 24 carbon atoms, an aryl radical containing 6 to 24 carbon atoms or an aralkyl radical containing 7 to 24 carbon atoms. Preferably, J contains 4 to 18 carbon atoms, preferably 6 to 12 carbon atoms.

[0188] In one embodiment, monomer M4 has the general formula (IV), wherein:

[0189] -t is an integer equal to 0 or 1;

[0190] -u is an integer equal to 0 or 1;

[0191] -M and R8 are divalent linking groups and are different; M is C6 to C 18 Aryl, preferably phenyl, R8 is C7 to C 24 Aralkyl, preferably benzyl;

[0192] -X is a functional group selected from -OC(O)-, -C(O)-O-, -C(O)-N(H)- and -O-, preferably -C(O)-O- or -OC(O)-;

[0193] R9 is selected from -H and -CH3, preferably -H;

[0194] R10 and R 11 Different; R 10 or R 11 One of the groups is H, R 10 or R 11 Another of the groups is a hydrocarbon chain, preferably a linear alkyl group, having 1 to 24 carbon atoms, preferably 4 to 18 carbon atoms, preferably 6 to 12 carbon atoms.

[0195] In one embodiment, monomer M4 is a styrene monomer. In this case, in formula (IV): u=1, R9 is H, R8 represents a C6 to C 18 Aryl or C7 to C 24 The double bond of the monomer M4 of formula (IV) is directly connected to the aryl group.

[0196] Advantageously, R of the monomer M4 of the general formula (IV) 10 , M, X and u are integers equal to 0 or 1 (R8) u The total number of carbon atoms in the chain formed by linking the groups is from 8 to 38, preferably from 10 to 26.

[0197] Synthesis of monomer M4 of formula (IV)

[0198] The monomer M4 of formula (IV) as described above is obtained according to the method described in WO2015 / 110642 or WO2015 / 110643.

[0199] Monomer M5 of general formula (V):

[0200] Monomer M5 of borate copolymer compound A2 has the general formula (V):

[0201]

[0202] in:

[0203] -R 12 Selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0204] -R 13 Selected from C6 to C 18 Aryl and R' 13 、-C(O)-OR' 13 、-OR' 13 、-SR' 13 and -C(O)-N(H)-R' 13 C6 to C 18 Aryl, where R' 13 Indicates H or C1 to C 25 alkyl.

[0205] "C1 to C 25 "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing from 1 to 25 carbon atoms. Preferably, the hydrocarbon chain is linear.

[0206] "Being R' 13 C6 to C 18 The term "aryl" is understood to mean an aromatic hydrocarbon compound containing 6 to 18 carbon atoms, at least one carbon atom of the aromatic ring of which is replaced by a C1 to C 25 Alkyl substitution.

[0207] Among the monomers of formula (V), the monomers corresponding to formula (VA) form part of the preferred monomers:

[0208]

[0209] in:

[0210] -R2 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0211] -R' 13 Indicates H or C1 to C 25 Alkyl, preferably H or linear C1 to C 25 Alkyl, more preferably H or linear C3 to C 15 Alkyl, more preferably H or linear C5 to C 15 alkyl.

[0212] According to another embodiment, monomer M5 is a styrene monomer. In this case, in formula (V): R 12 Indicates H, R 13 Selected from C6 to C 18 Aryl and R' 13 C6 to C 18 Aryl, R' 13 Indicates H or C1 to C 25 Alkyl, the double bond of the monomer M5 of formula (V) is directly connected to the aryl group.

[0213] Advantageously, according to this embodiment, monomer M5 is styrene.

[0214] Obtaining Monomer M5:

[0215] The monomers of formula (V) and (VA) are well known to those skilled in the art. and sell.

[0216] Monomer M3

[0217] The third monomer M2 of the comb copolymer A2 of the present invention has the general formula (X):

[0218]

[0219] in:

[0220] - Z1, Z2 and Z3 are the same or different and represent a hydrogen atom, a C1 to C 12 alkyl or -OZ' or -C(O)-O-Z' group, wherein Z' is C1 to C 12 alkyl.

[0221] "C1 to C 12 "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing from 1 to 12 carbon atoms. Preferably, the hydrocarbon chain is linear. Preferably, the hydrocarbon chain contains from 1 to 6 carbon atoms.

[0222] Advantageously, Z1, Z2 and Z3 are identical or different and represent a group chosen from a hydrogen atom, a C1 to C6 alkyl group or an -OZ' or -C(O)-O-Z' group, wherein Z' is a C1 to C6 alkyl group.

[0223] More preferably, Z1, Z2 and Z3 are identical or different and represent a group selected from a hydrogen atom, a C1 to C4 alkyl group or a -OZ' or -C(O)-O-Z' group, wherein Z' is a C1 to C4 alkyl group.

[0224] Among the preferred monomers M3, mention may be made of styrene, p-(tert-butyl)styrene, p-methoxystyrene, p-acetoxystyrene or 2,4,6-trimethylstyrene.

[0225] According to a preferred embodiment, M3 is styrene.

[0226] Get monomer M3

[0227] Some monomers of formula (X), such as styrene, p-(tert-butyl)styrene, p-methoxystyrene, p-acetoxystyrene or 2,4,6-trimethylstyrene, are well known to those skilled in the art. Other monomers can be prepared from these commercially available monomers by synthetic methods well known to those skilled in the art.

[0228] Monomer M6

[0229] Monomer M6 has the general formula (IX):

[0230]

[0231] in:

[0232] Q1 is selected from -H, -CH3 and -CH2-CH3;

[0233] Q2 is selected from the group consisting of -Q', -O-Q', -C(O)-O-Q', -OC(O)-Q', S-Q', -S-(CH2)2-C(O)-O-Q', -N(H)-C(O)-Q' and C(O)-N(H)-Q', wherein Q' is a polyolefin,

[0234] n represents an integer selected from 0 and 1,

[0235] A represents a group selected from -A1-, -O-(-A2-O-) n' -A1-, -C(O)-O-(-A2-O-) n' -A1-、-OC(O)-(-A2-O-) n' -A1-、-S-(-A2-O-) n' -A1-, -N(H)-C(O)-(-A2-O-) n' -A1- and -C(O)-N(H)-(-A2-O-) n' -A1- divalent group, wherein

[0236] A1 is selected from C1 to C 30 Alkyl, C6 to C 30 Aryl or C6 to C 30 A divalent aralkyl group,

[0237] A2 is a divalent group selected from C2 to C4 alkyl groups,

[0238] n' is an integer, and n' represents 0 or 1.

[0239] For example, A2 can be selected from:

[0240] -CH2-CH2-, -CH2-CH2-CH2-, -CH2-C(CH3)H-.

[0241] Preferably, A2 is linear; more preferably, A2 represents -CH2-CH2-.

[0242] Preferably, in formula (IX), Q1 represents -H.

[0243] Preferably, in formula (IX), Q2 is selected from -Q', -S-(CH2)2-C(O)-O-Q' or -C(O)-O-Q' groups, wherein Q' is a polyolefin.

[0244] According to a first alternative form, n=0 and Q1=CH3.

[0245] According to a second alternative form, n=1, n'=0, Q1=H, and A1 is selected from C1 to C 12 Alkyl, C6 to C 12 Aryl or C6 to C 12 Aralkyl.

[0246] Preferably, according to the second alternative form, n=1, Q1=H and A=p-phenyl.

[0247] Macromonomers based on polyolefins, for example those of formula (IX) are known. These repeat units comprise at least one Q' group derived from a polyolefin.

[0248] Preferably, in formula (IX), Q' represents a polyolefin derived from an olefin or from a diene, for example ethylene, propylene, n-butene, isobutylene, butadiene, isoprene, or a hydrogenated polyolefin.

[0249] The repeating units M6 derived from polyolefin-based macromonomers preferably contain at least 90% by weight, more preferably at least 92.5% by weight, preferably at least 95% by weight, of groups derived from olefins and / or dienes, relative to the weight of the repeating units M6. The polyolefin groups Q' may also be present in hydrogenated form.

[0250] Preferably, Q' represents a polyolefin selected from polybutadiene having a number average molecular weight of 400 to 50000 g / mol, preferably 500 to 50000 g / mol, more preferably 500 to 10000 g / mol, in particular 500 to 5000 g / mol or more preferably 700 to 3000 g / mol.

[0251] Preferably, Q' represents a polyolefin comprising 30 to 500 carbon atoms, preferably 50 to 400 carbon atoms, or 70 to 200 carbon atoms.

[0252] · The repeating unit corresponding to monomer M6 is obtained

[0253] The repeating units corresponding to monomer M6 can be obtained by any method known to those skilled in the art.

[0254] The monomer M6 in which Q1 is H, Q2 is -C(O)-O-Q', and Q' is a polyolefin or a hydrogenated polyolefin can be obtained by the reaction of acrylic anhydride with an alcohol Q'OH.

[0255] The monomer M6 in which Q1 represents CH3, Q2 represents -C(O)-O-Q', and Q' is a polyolefin can be obtained by the reaction of acrylic acid with alcohol Q'OH, the reaction of acryloyl chloride with alcohol Q'OH, or the reaction of methacrylic anhydride with alcohol Q'OH.

[0256] Alternatively, repeating units corresponding to the monomer M6 in which Q1 represents H and CH3, Q2 represents -C(O)-O-Q', and Q' is a polyolefin or a hydrogenated polyolefin can be introduced by functionalizing the main chain after polymerization, for example in the following order:

[0257] Acrylic acid or methacrylic acid is copolymerized with other monomers, such as monomer M1 of formula (I) and optionally monomer M2 of formula (II) and / or monomer M3 of formula (X), to form the main chain of comb copolymer A1,

[0258] At least a portion of the acid functional groups of the (meth)acrylic monomers are esterified by reaction with the alcohol Q'OH.

[0259] The polyolefin alcohols used can be prepared in particular by synthesizing hydroxy-terminated polybutadienes as taught in US Pat. No. 5,159,123 and then hydrogenating them, for example by the process described in US Pat. No. 7,148,292.

[0260] Among commercially available polyolefin alcohols that can be used, mention may be made of the polybutadiene Krasol HLBH 5000M sold by Cray Valley.

[0261] For other alternative forms of Q2, those skilled in the art similarly use conventional reactions to functionalize the polymerizable groups before or after the main chain polymerization of copolymer A1, in particular by esterification or amidation reactions, by thiol-ene coupling reactions, by Michael addition reactions between thiol functional groups and acrylate, acrylamide or maleimide functional groups, and the like.

[0262] · Obtain side chains based on M4 / M5 / M3 oligomers:

[0263] Oligomeric side chains can be obtained directly by copolymerizing:

[0264] -monomers involved in the main chain,

[0265] and

[0266] at least one oligomer comprising a polymerizable functional group and repeating units corresponding to the monomer M5 of the general formula (V), and optionally a monomer M4 of the general formula (IV) and / or a monomer M3 of the general formula (X).

[0267] According to a preferred embodiment, the side chains are obtained by copolymerizing the monomers participating in the constitution of the main chain with at least one "branching" monomer and then grafting the oligomers to the branching functional groups.

[0268] Branching monomers are monomers comprising a polymerizable functional group such as a vinyl or acrylic double bond and at least one reactive functional group which enables:

[0269] - grafted pre-oligomerized side chains, or

[0270] - Initiate polymerization.

[0271] Preferably, the branching monomer is selected from free radical polymerization initiators and transfer agents. The reactive functional groups capable of initiating side chain polymerization may, for example, consist of brominated functional groups, as described in detail in the experimental section. Other reactive functional groups well known to those skilled in the art may also be used, such as RAFT agents, free radical polymerization agents in the presence of nitrogen oxides (NMP), mercaptans, diazo, peroxides.

[0272] Preferably, the branched monomer M7 corresponds to the following formula (XII):

[0273]

[0274] in:

[0275] G1 represents a group selected from -H, -CH3, -CH2-CH3;

[0276] M represents a hydrocarbon group containing 1 to 40 carbon atoms, optionally containing one or more functional groups selected from -O-, -OC(O)-, -OC(O)-O-, -N(H)-, -N=, -N(H)-C(O)-, -N(H)-C(O)-N(H)-, -S-, -SC(O)- or -SC(S)-O-;

[0277] G2 represents a group selected from Cl, Br, I, -C(O)-OH, -G3 or -C(O)-OG3, wherein G3 is C1 to C 12 alkyl.

[0278] As examples of branching monomers, mention may be made of acrylic, methacrylic, brominated and xanthate monomers.

[0279]

[0280] · Other monomers

[0281] In addition to the repeating units corresponding to the monomers M4, M5, M3 and M6 described in detail above, the comb polymer A1 according to the invention may comprise in the main chain further repeating units derived from other comonomers, as in the side chains, in a proportion of up to 20% by weight, preferably up to 10% by weight and more preferably up to 5% by weight, based on the total weight of the repeating units constituting the copolymer A2.

[0282] Structure of comb-type boric acid copolymer A2

[0283] The comb-type boric acid copolymer A2 comprises a main chain or backbone chain and at least one side chain or pendant chain.

[0284] Preferably, the comb-type boronic acid copolymer A2 comprises more than two oligomeric side chains or pendant chains.

[0285] Preferably, the main chain comprises at least repeating units corresponding to monomer M5 of formula (V).

[0286] Preferably, the main chain further comprises at least a repeating unit corresponding to the monomer M3 of formula (X).

[0287] The main chain advantageously comprises recurring units corresponding to the monomer M4 of formula (IV).

[0288] The side chains may in particular be selected from:

[0289] o A group Q2 group as defined in formula (IX) above, which is selected from -Q', -O-Q', -C(O)-O-Q', -OC(O)-Q', -S-Q', -S-(CH2)2-C(O)-O-Q', -N(H)-C(O)-Q' and -C(O)-N(H)-Q', wherein Q' is a polyolefin.

[0290] The Q2 group can be connected to the main chain through an A group selected from the following: A represents a group selected from -A1, -O-(A2-O) n' -A1, -C(O)-O-(A2-O) n' -A1, -OC(O)-(A2-O) n' -A1, -S-(A2-O) n' -A1, -N(H)-C(O)-(A2-O) n' -A1 and -C(O)-N(H)-(A2-O) n' -A1 divalent group, wherein:

[0291] A1 is selected from C1 to C 30 Alkyl, C6 to C 30 Aryl or C6 to C 30 A divalent aralkyl group,

[0292] A2 is a divalent group selected from C2 to C4 alkyl groups,

[0293] n' is an integer, n' represents 0 or 1,

[0294] o Oligomers consisting of repeating units corresponding to monomer M5 and optionally monomers M4 and / or M3.

[0295] Therefore, repeating units corresponding to the monomer M4 and corresponding to the monomers M5 and M3 may be contained in the main chain and / or the side chain.

[0296] The different possible distributions of functionality of these copolymers have been described in Fig. 6A , Figure 6B and Figure 6C Indicated in.

[0297] In these Figures, boronate functional groups (such as those carried by monomer M4 of formula (IV)) are indicated as "F".

[0298] exist Fig. 6A In , the main chain (P) comprises borate functional groups, while the side chains (L) do not comprise them. For example, this diagram may correspond to a copolymer based on monomers M4, M5 and optionally M3 and on olefin macromonomer M6.

[0299] exist Figure 6B In the diagram, the main chain (P) does not contain borate functional groups, while some side chains (Lb) contain them, but the side chains (La) do not. For example, this diagram may correspond to a copolymer based on monomers M5 and M3 and an olefin macromonomer M6 (La), the side chains (Lb) being oligomers of M4 and M5 and optionally M3, which are grafted onto the main chain.

[0300] exist Figure 6C In the diagram, the main chain (P) and some of the side chains (Lb) contain borate functional groups. For example, the diagram may correspond to a copolymer based on monomers M4 and M5 and optionally M3 and based on an olefin macromonomer M6, the macromonomer M6 forming the side chains (La) as side chains of oligomers of M4 and M5 grafted onto the main chain to form the side chains (Lb).

[0301] Preferred borate comb copolymers A2

[0302] Preferably, the oligomeric side chains represent 20% to 95% by weight, relative to the total weight of copolymer A2.

[0303] According to a first preferred alternative form, the oligomeric side chains O1 comprising polyolefin segments represent from 20% to 70% by weight relative to the total weight of the copolymer A2.

[0304] According to a second preferred alternative, the oligomeric side chains O2 comprising at least repeating units of a monomer M5 corresponding to the general formula (V) and optionally repeating units of a monomer M4 corresponding to the general formula (IV) and / or repeating units of a monomer M3 corresponding to the general formula (X) represent 30% to 95% by weight, relative to the total weight of the copolymer A2.

[0305] Preferably, the non-oligomeric side chains represent 5% to 80% by weight, relative to the total weight of copolymer A2.

[0306] Preferably, the repeating unit of formula (X) is 2 mol% to 50 mol% relative to the total moles of the monomers constituting copolymer A2.

[0307] Preferably, the repeating unit corresponding to the monomer M5 is 10 mol % to 90 mol %, preferably 30 mol % to 80 mol %, relative to the total moles of the monomers constituting the copolymer A2.

[0308] Preferably, the repeating unit corresponding to the monomer M4 is 1 mol% to 50 mol%, preferably 5 mol% to 30 mol%, relative to the total moles of the monomers constituting the copolymer A2.

[0309] When calculating the mol % of repeating units and / or monomers (e.g. M4, M5 or M3) relative to the total number of moles of the monomers constituting copolymer A2, and when the latter comprise one or more side chains comprising polyolefin-type segments, this is included in the polyolefin segment by treating it as a single monomer (M6).

[0310] In one embodiment, the preferred comb copolymer comprises at least:

[0311] - a repeating unit corresponding to the first monomer M4 of the above general formula (IV);

[0312] - a repeating unit corresponding to the second monomer M5 of the above formula (V), preferably formula (VA);

[0313] - a repeating unit corresponding to the third monomer M6 of formula (IX) above, advantageously a monomer M6 of formula (IX) in which Q1 represents H, n=0, Q2 is -CO-O-Q' and Q' represents an olefin.

[0314] Method for obtaining borate comb copolymer A2

[0315] A person skilled in the art can, with the aid of his general knowledge, synthesize comb copolymers A2 comprising at least two borate functional groups.

[0316] Copolymerization can be initiated by free radical generating compounds in bulk or in solution in an organic solvent. For example, the copolymers of the present invention are obtained by known free radical copolymerization methods, particularly controlled radical copolymerization methods, such as methods known as reversible addition-fragmentation chain transfer (RAFT) free radical polymerization and methods known as atom transfer radical polymerization (ARTP). Telomerization and conventional free radical polymerization can also be used to prepare copolymers of the present invention (Moad, G. and Solomon, DH, The Chemistry of Radical Polymerization, 2nd Ed., Elsevier Ltd, 2006, p. 639; Matyaszewski, K. and Davis, TP, Handbook of Radical Polymerization, Wiley-Interscience, Hoboken, 2002, p. 936).

[0317] According to a preferred embodiment, the copolymerization is carried out by conventional free radical synthesis in the absence of a RAFT chain transfer agent.

[0318] The borate comb copolymer A2 is prepared according to a preparation process comprising at least one polymerization stage (a), in which:

[0319] i) a monomer selected from the group consisting of monomer M4 of general formula (IV), M5 of general formula (V), M3 of general formula (X), M7 of general formula (XII), and monomer M6 of general formula (IX) as described above;

[0320] ii) at least one source of free radicals.

[0321] In one embodiment, the process may further comprise iii) at least one chain transfer agent.

[0322] "Free radical source" is understood to mean a compound which can generate a chemical entity with one or more unpaired outermost electrons. A person skilled in the art can use any known free radical source suitable for the polymerization process, in particular the controlled free radical polymerization process. Among the free radical sources, benzoyl peroxide, tert-butyl peroxide, diazo compounds such as azobisisobutyronitrile, peroxidic compounds such as persulfates or hydrogen peroxide, redox systems such as Fe 2+ Oxidizing systems, persulfate / sodium metabisulfite mixtures or ascorbic acid / hydrogen peroxide or compounds which can be cleaved photochemically or by ionizing radiation (eg UV) or by beta or gamma radiation.

[0323] "Chain transfer agent" is understood to mean a compound whose purpose is to provide uniform growth of macromolecular chains by a reversible transfer reaction between a growing entity (i.e. a polymer chain terminated by a carbon-based free radical) and a dormant entity (i.e. a polymer chain terminated by a transfer agent). This reversible transfer process makes it possible to control the molecular weight of the copolymer thus prepared. Preferably, in the process of the invention, the chain transfer agent comprises a thiocarbonylthio-SC(=S)-group. Examples of chain transfer agents may include dithioesters, trithiocarbonates, xanthates and dithiocarbamates. Preferred transfer agents are cumyl dithiobenzoate or 2-cyano-2-propylbenzodithioester.

[0324] A "chain transfer agent" is also understood to be a compound whose purpose is to limit the growth of macromolecular chains during their formation by adding monomer molecules and to initiate new chains, which makes it possible to limit the final molecular weights or even control them. Transfer agents of this type are used in telomerization reactions. A preferred transfer agent is cysteamine.

[0325] In one embodiment, the process for preparing the comb copolymer A2 comprises at least one polymerization stage (a) as described above, wherein at least one branching monomer M7 has the general formula (XII), which polymerization stage is followed by:

[0326] (b) Optionally, functionalization of the branched monomer M7

[0327] (c) at least one oligomerization stage starting from a branching monomer M7 (or a functional group derived from M7), or

[0328] (d) at least one stage of grafting oligomers starting from branching monomers M7 (or functional groups derived from M7).

[0329] According to one embodiment (when free radical polymerization is carried out using a RAFT chain transfer agent), after direct synthesis of the polymer comprising diol functional groups, the process comprises a stage of removal of the RAFT chain ends by aminolysis followed by Michael addition.

[0330] The preferences and definitions stated for the general formulae (VI), (V), (IX), (X) and (XII) also apply to the above-described processes.

[0331] A person skilled in the art can use various synthetic schemes to introduce side chains into the borate ester copolymer A2.

[0332] By grafting synthesis Figure 7 As shown:

[0333] In stage E1 , the monomers M4, M5 and optionally M3 are copolymerized with the branching comonomer M7 to form the main chain (P).

[0334] Monomer M4 forms a repeating unit comprising a borate functional group represented by the letter F.

[0335] The monomer M7 forms a repeating unit comprising a branching functional group represented by the letter F' (a plurality of different functional groups F' may be present).

[0336] In stage E2, the main chain (P) is grafted with side chains (La), for example polyolefin chains, via partial functional groups F'.

[0337] In stage E3, the main chain (P) is grafted with side chains (Lb) via the remaining functional groups F', for example oligomeric chains resulting from the copolymerization of monomers M4 and M5 and optionally M3, these side chains carrying the borate functional group denoted F belonging to monomer M4.

[0338] Figure 8 The synthesis is represented by methods of copolymerization of macromonomers and grafting of oligomers, both techniques allowing the introduction of side chains:

[0339] In stage E1 , various monomers are reacted: olefin macromonomer M6 , monomer M4 comprising a borate functional group F, monomer M7 comprising a branching functional group F′ and acrylate monomer M5 .

[0340] In stage E2 , a comb copolymer is obtained having a main chain (P) with olefin side chains (La), borate functional groups F, branching functional groups F′ and acrylate functional groups (not shown).

[0341] The branched functional groups F' of the copolymer react with the acrylate monomers M5 and the borate monomers M4 to produce, in stage E3, a comb copolymer having a main chain (P) with:

[0342] - Acrylate functional group (not shown)

[0343] - olefin side chain (La),

[0344] - borate functional group (F),

[0345] - side chains (Lb) comprising borate functional groups (F) and acrylate functional groups (not shown).

[0346] Properties of poly(borate) copolymer compound A2

[0347] The borate copolymer A2 is a comb-type copolymer. A "comb-type copolymer" is understood to mean a copolymer having a main chain (also referred to as backbone) and oligomeric side chains. The side chains extend from both sides of the main chain. Figure 2 A comb polymer is shown.

[0348] Copolymer A2 exhibits a main chain formed by polymerizable functional groups, in particular methacrylate functional groups, preferably styrene functional groups, and a mixture of hydrocarbon side chains, substituted or unsubstituted by borate functional groups, some of which are oligomeric and others of which are monomeric side chains, which are non-oligomeric.

[0349] The side chains of copolymer A2 may be:

[0350] - chains produced from monomers of formula (VI), (V) and (X),

[0351] - polyolefins, in particular macromonomers M6 corresponding to formula (IX),

[0352] - Oligomers obtained by polymerization of monomers of formula (VI) and (V) and optionally monomers of (X).

[0353] The monomers of formula (IV), (V) and (X) have polymerizable functional groups whose reactivity can lead to the formation of copolymers, and the monomers having borate functional groups are distributed statistically or in a gradient manner or mixedly along the main chain of the copolymer or on the side chains.

[0354] The borate comb copolymer A2 has the advantage of being sensitive to external stimuli such as temperature, pressure or shear rate; this sensitivity is reflected in property changes. In response to the stimulus, the spatial conformation of the copolymer chain is changed and the borate functional groups become more or less susceptible to association reactions, resulting in crosslinking as well as exchange reactions. These association and exchange processes are reversible. The comb copolymer A2 is a thermosensitive copolymer, that is, it is sensitive to temperature changes.

[0355] Advantageously, the borate copolymer A2 has a molar percentage of monomer of formula (IV) in the copolymer of from 0.25% to 30%, preferably from 1% to 25%, more preferably from 5% to 20%.

[0356] Advantageously, the borate copolymer A2 has a molar percentage of monomers of formula (IV) in the copolymer of 0.25% to 30%, preferably 1% to 25%, and a molar percentage of monomers of formula (V) in the copolymer of 70% to 99.75%, preferably 75% to 99%.

[0357] Advantageously, the borate copolymer A2 has a molar percentage of styrene monomers of formula (IV), (V) and / or (X) in the copolymer of 2 to 50 mol %, preferably 3 to 40 mol %, more preferably 5 to 35 mol %.

[0358] The "molar percentage of styrene monomers" is understood to mean the sum of the contents of each styrene monomer in the borate copolymer A2, and the styrene monomers may be:

[0359] · having formula (IV), wherein: u=1, R9 is H, and R8 represents C6 to C 18 Aryl or C7 to C 24 The double bond of the monomer M4 of formula (IV) is directly connected to the aryl group.

[0360] · having the formula (V), wherein: R 12 Indicates H, R 13 Selected from C6 to C 18 Aryl and R' 13 C6 to C 18 Aryl, R' 13 Indicates H or C1 to C 25 Alkyl, the double bond of the monomer M5 of formula (V) is directly connected to the aromatic group;

[0361] and / or

[0362] • having formula (X), as described above.

[0363] Advantageously, the number average degree of polymerization of the main chain of the borate copolymer A2 is from 50 to 1500, preferably from 50 to 800. The degree of polymerization is controlled in a known manner when the copolymers of the invention are prepared by conventional free radical polymerization, by using controlled free radical polymerization techniques, free radical polymerization techniques in the presence of transfer agents (also referred to as telomerization in some cases) or by adjusting the amount of free radical source.

[0364] Advantageously, the polydispersity index (PI) of the borate copolymer A2 is between 1.04 and 3.54, preferably between 1.10 and 3.10. These values ​​are obtained by size exclusion chromatography.

[0365] Advantageously, the number-average molar mass of the borate copolymer A2 is from 10,000 g / mol to 200,000 g / mol, preferably from 25,000 g / mol to 100,000 g / mol. These values ​​are obtained by size exclusion chromatography.

[0366] Compound A2, in particular the borate copolymer, exhibits the property of being able to react with a compound having a diol functional group in a hydrophobic medium, in particular a non-polar medium, by an ester exchange reaction. The ester exchange reaction can be represented according to the following Scheme 9:

[0367]

[0368] Thus, during the transesterification reaction, a boric acid ester having a chemical structure different from that of the starting boric acid ester is formed by exchanging the hydrocarbon groups represented by

[0369]

[0370] Polyglycol compound A1

[0371] The diol compound A1 may be a small molecule or a macromolecular monomer.

[0372] Preferably, the polyglycol compound A1 is a polymer comprising repeating units corresponding to at least one monomer functionalized with a diol functional group. Preferably, the polyglycol compound A1 is a copolymer comprising repeating units corresponding to at least one monomer M1 functionalized with a diol functional group and at least one monomer M2, the structure of at least one monomer M2 being different from that of the monomer M1. Advantageously, the polyglycol compound A1 is a copolymer comprising repeating units corresponding to at least one monomer M1 functionalized with a diol functional group, at least one monomer M2 having a different structure from the monomer M1 and at least one styrene monomer M3 having a different structure from the monomers M1 and M2. According to a preferred alternative form, the polyglycol compound A1 is a copolymer comprising repeating units corresponding to at least one monomer M1 functionalized with a diol functional group, at least one monomer M2 having a different structure from the monomer M1, at least one styrene monomer M3 having a different structure from the monomers M1 and M2 and at least one olefin monomer M6.

[0373] Monomer M1

[0374] The first monomer M1 of the comb polymer (A1) of the present invention has the general formula (I):

[0375]

[0376] in:

[0377] -R1 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0378] -Y represents a group consisting of C1 to C 20 A divalent linking group of an alkyl chain, which optionally contains one or more than one ether-O-bridge; preferably, Y represents a group selected from: -(CH2) x -or-(CH2) x' -O-(CH2) x "-chain

[0379] and

[0380] x is an integer from 1 to 18, preferably from 2 to 18, more preferably from 3 to 8; more preferably, x is equal to 4;

[0381] x' and x" are integers from 1 to 17, x'+x" is an integer from 2 to 18, more preferably an integer from 3 to 8; advantageously, x' is an integer from 1 to 4, x"=1; more preferably, x'=2, x"=1;

[0382] y is an integer equal to 0 or 1; preferably, y is equal to 0;

[0383] X1 and X2 are the same or different and are selected from hydrogen, tetrahydropyranyl, methoxymethyl, tert-butyl, benzyl, trimethylsilyl and tert-butyldimethylsilyl;

[0384] or

[0385] X1 and X2 form a bridge of the following formula with the oxygen atom:

[0386]

[0387] in:

[0388] -asterisk ( * ) represents a bond to an oxygen atom,

[0389] - R'2 and R"2 are the same or different and are selected from hydrogen and C1 to C 11 alkyl;

[0390] or

[0391] X1 and X2 form a boric acid ester with the oxygen atom:

[0392]

[0393] in:

[0394] -asterisk ( * ) represents a bond to an oxygen atom,

[0395] -R"'2 is selected from C6 to C 30 Aryl, C7 to C 30 Arylalkyl and C2 to C 30 Alkyl, preferably C6 to C 18 Aryl, more preferably phenyl.

[0396] Preferably, when R'2 and R"2 are C1 to C 11 When C1 to C 11 The alkyl group is selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and n-undecyl. 11 The alkyl group is methyl.

[0397] Preferably, when R"'2 is C2 to C 30 When the monomer M1 is an alkyl group, the hydrocarbon chain is a linear chain. More preferably, the monomer M1 corresponds to the general formula (Ia):

[0398]

[0399] x is an integer from 1 to 18, preferably from 2 to 18, more preferably from 3 to 8; more preferably, x is equal to 4.

[0400] Among the monomers of formula (I), the monomers corresponding to formula (IA) form part of the preferred monomers:

[0401]

[0402] in:

[0403] R1 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0404] Y represents a group selected from -(CH2) x -or-(CH2) x' -O-(CH2) x” - a divalent linking group of the chain,

[0405] and

[0406] x is an integer from 1 to 18, preferably from 2 to 18, more preferably from 3 to 8; more preferably, x is equal to 4;

[0407] x' and x" are integers from 1 to 17, x'+x" is an integer from 2 to 18, more preferably an integer from 3 to 8; advantageously, x' is an integer from 1 to 4, x"=1; more preferably, x'=2, x"=1;

[0408] y is an integer equal to 0 or 1; preferably, y is equal to 0.

[0409] Among the monomers of formula (IA), those corresponding to formula (Ia-A) form part of the preferred monomers:

[0410]

[0411] wherein R1, x and y have the same definitions and the same preferences as in formula (IA).

[0412] Among the monomers of formula (I), monomers corresponding to formula (IB) form part of the preferred monomers:

[0413]

[0414] in:

[0415] R1 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0416] Y represents a group selected from -(CH2) x -or-(CH2) x' -O-(CH2) x” - a divalent linking group of the chain,

[0417] and

[0418] x is an integer from 1 to 18, preferably from 2 to 18, more preferably from 3 to 8; more preferably, x is equal to 4;

[0419] x' and x" are integers from 1 to 17, x'+x" is an integer from 2 to 18, more preferably an integer from 3 to 8; advantageously, x' is an integer from 1 to 4, x"=1; more preferably, x'=2, x"=1;

[0420] y is an integer equal to 0 or 1; preferably, y is equal to 0;

[0421] Y1 and Y2 are the same or different and are selected from tetrahydropyranyl, methoxymethyl, tert-butyl, benzyl, trimethylsilyl and tert-butyldimethylsilyl;

[0422] or

[0423] -Y1 and Y2 form a bridge of the following formula with the oxygen atom:

[0424]

[0425] in:

[0426] -asterisk ( * ) represents a bond to an oxygen atom,

[0427] - R'2 and R"2 are the same or different and are selected from hydrogen and C1 to C 11 alkyl;

[0428] or

[0429] -Y1 and Y2 form a boric acid ester with the oxygen atom:

[0430]

[0431] in:

[0432] -asterisk ( * ) represents a bond to an oxygen atom,

[0433] -R"'2 is selected from C6 to C 30 Aryl, C7 to C 30 Arylalkyl and C2 to C 30 Alkyl, preferably C6 to C 18 Aryl, more preferably phenyl.

[0434] Preferably, when R'2 and R"2 are C1 to C 11 When C1 to C 11 The alkyl group is selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and n-undecyl. 11 The alkyl group is methyl.

[0435] Preferably, when R"'2 is C2 to C 30 In the case of an alkyl group, the hydrocarbon chain is a linear chain.

[0436] Among the monomers of formula (IB), those corresponding to formula (Ia-B) form part of the preferred monomers:

[0437]

[0438] wherein R1, x, y, Y1 and Y2 have the same definitions and the same preferences as in formula (IB).

[0439] Examples of preferred diol monomers of formula (I) are shown below:

[0440]

[0441]

[0442] The synthesis of the comb-type polyglycol copolymer (A1) may comprise copolymerizing the protected form of the monomer (IB) with other comonomers and then deprotecting the diol functional group of the monomer (IB).

[0443] Obtain monomer M1

[0444] The monomer M1 of the general formula (I) is obtained according to the methods described in WO2015 / 110642, WO2015 / 110643 and WO2016113229, the synthesis of which is described in the experimental part of these applications.

[0445] Monomer M2

[0446] The second monomer of the comb copolymer A1 of the present invention has the general formula (II):

[0447]

[0448] in:

[0449] -R2 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0450] -R3 is selected from C6 to C 18 Aryl and C6 to C6 substituted with R'3, -C(O)-O-R'3, -O-R'3, -S-R'3 and -C(O)-N(H)-R'3 18 Aryl, wherein R'3 is C1 to C 30 alkyl.

[0451] Preferably, R'3 is C1 to C30 Alkyl, whose hydrocarbon chain is linear.

[0452] Among the monomers of formula (II), the monomers corresponding to formula (II-A) form part of the preferred monomers:

[0453]

[0454] in:

[0455] -R2 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0456] -R"3 is C1 to C8 alkyl.

[0457] "C1 to C8 alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing 1 to 8 carbon atoms. Preferably, the hydrocarbon chain is linear.

[0458] Preferably, the units corresponding to monomer (IIA) are present in the main chain of copolymer A1.

[0459] Among the monomers of formula (II), monomers corresponding to formula (II-B) also form part of the preferred monomers:

[0460]

[0461] in:

[0462] -R2 is selected from -H, -CH3 and -CH2-CH3, preferably -H and -CH3;

[0463] -R"3 is C9 to C 30 alkyl.

[0464] "C9 to C 30 "Alkyl" is understood to mean a saturated linear or branched hydrocarbon chain containing 9 to 30 carbon atoms. Preferably, the hydrocarbon chain is linear.

[0465] Preferably, the units corresponding to monomer (IIB) are present in the oligomeric side chains of copolymer A1.

[0466] Obtain monomer M2

[0467] The monomers of formula (II), (II-A) and (II-B) are well known to those skilled in the art. and sell.

[0468] Monomer M3

[0469] The third monomer of the comb copolymer A1 of the invention corresponds to the general formula (X), the parameters of which have the same definitions as those of the monomer M3 used in the synthesis of the copolymer A2 described above.

[0470]

[0471] Preferred monomers M3 for the synthesis of A1 are the same as for the synthesis of A2.

[0472] Monomer M6

[0473] The monomer M6 has the general formula (IX), the parameters of which have the same definitions as for the monomer M6 used in the synthesis of the copolymer A2 described above:

[0474]

[0475] Preferred monomers M6 for the synthesis of A1 are the same as for the synthesis of A2.

[0476] Other monomers

[0477] In addition to the repeating units corresponding to the monomers M1, M2, M3 and M6 described in detail above, the copolymer A1 may contain in the main chain further repeating units derived from other comonomers, as in the side chains, in a proportion of up to 20% by weight, preferably up to 10% by weight, more preferably up to 5% by weight, based on the total weight of the repeating units constituting the copolymer A1.

[0478] Structure of copolymer A1

[0479] Copolymer A1 may be a linear or branched copolymer, in particular a comb copolymer.

[0480] When these are comb copolymers, copolymer A1 may contain oligomeric side chains and side chains that are not oligomeric. When monomers M1, M2 and / or M3 are introduced into the main chain of copolymer A1, the chains of monomers M1, M2 and M3 form the non-oligomeric side chains of these polymers.

[0481] When A1 is a comb copolymer, monomers M1, M2 and M3 may be present in the main chain and / or in the side chain. In the side chain, they are present in the form of oligomers. Optionally, other monomers may be present in the main chain and / or in the side chain.

[0482] Monomer M6 can be used in the copolymerization of the main chain and can provide the oligomeric side chain O1.

[0483] According to a second alternative form, the comb copolymer A1 comprises oligomeric side chains O2 comprising at least recurring units corresponding to monomer M2 of formula (II) and optionally recurring units corresponding to monomer M1 of formula (I) and / or recurring units corresponding to monomer M3 of formula (X).

[0484] Copolymer A1 can be a random copolymer or a gradient copolymer or a mixed random / gradient copolymer.

[0485] Preferred polyglycol copolymers

[0486] In one embodiment, the preferred diol copolymer A1 comprises at least:

[0487] - a repeating unit corresponding to the first monomer M1 of the above general formula (I); in particular, a repeating unit corresponding to the first monomer M1 of the above general formula (IA);

[0488] - a repeating unit corresponding to the second monomer M2 of the above formula (II), wherein R2 is -CH3 and R3 is a -C(O)-O-R'3 group, wherein -R'3 represents H or C1 to C 30 alkyl;

[0489] - a repeating unit corresponding to the third monomer M3 of the above general formula (X); in particular styrene.

[0490] In another embodiment, the preferred comb copolymer comprises at least:

[0491] - a repeating unit corresponding to the first monomer M1 of the above general formula (I); in particular, a repeating unit corresponding to the first monomer M1 of the above general formula (IA);

[0492] - a repeating unit corresponding to the second monomer M2 of the above formula (II-A), wherein R2 is -CH3, R3 is a -C(O)-O-R'3 group, and -R'3 represents H or a C1 to C8 alkyl group;

[0493] - a repeating unit corresponding to the third monomer M3 of the above general formula (X); in particular styrene,

[0494] - an oligomeric side chain O1 comprising at least one polyolefin segment, in particular corresponding to the side chain of a monomer M6 of formula (IX), more preferably Q2 is selected from a -Q' or -C(O)-O-Q' group, wherein Q' is a polyolefin or a hydrogenated polyolefin.

[0495] In another embodiment, preferred copolymer A1 comprises at least:

[0496] - a repeating unit corresponding to the first monomer M1 of the above general formula (I);

[0497] - a repeating unit corresponding to the second monomer M2 of the above formula (II-A);

[0498] - a repeating unit corresponding to the third monomer M2 of the above formula (II-B), which is different from the first monomer of the above formula (II-A); and

[0499] - repeating units corresponding to the fourth monomer M3 of the above general formula (X); in particular styrene.

[0500] According to this embodiment, preferred copolymers A1 comprise at least the repeating units corresponding to:

[0501] - the first monomer M1 of the above general formula (I);

[0502] - a second monomer M2 of formula (II-A), wherein R2 is -CH3 and R"3 is a C1 to C8 alkyl group, preferably a linear C1 to C8 alkyl group;

[0503] - a third monomer M2 of formula (II-B), wherein R2 is -CH3 and R"'3 is C9 to C 30 Alkyl, preferably linear C9 to C 30 Alkyl, more preferably linear C 12 To C 24 Alkyl; and

[0504] - a fourth monomer M3 of the abovementioned general formula (X), in particular styrene.

[0505] According to this embodiment, the preferred copolymer A1 is obtained by copolymerizing at least the following substances:

[0506] - the first monomer M1 of the above general formula (I);

[0507] - a second monomer M2 which is n-butyl methacrylate;

[0508] - a third monomer M2 selected from palmityl methacrylate, stearyl methacrylate, eicosanyl methacrylate and behenyl methacrylate,

[0509] - Optionally, a fourth monomer M3 of the abovementioned general formula (X), in particular styrene.

[0510] According to a preferred embodiment, the diol copolymer A1 is a comb copolymer.

[0511] In one embodiment, the preferred comb copolymer A1 comprises at least:

[0512] - a repeating unit corresponding to the first monomer M1 of the above general formula (I);

[0513] - a repeating unit corresponding to the second monomer M2 of the above formula (II), wherein R2 is -CH3 and R3 is a -C(O)-O-R'3 group, wherein -R'3 represents H or C1 to C 30 alkyl;

[0514] - a repeating unit corresponding to the third monomer M6 of formula (IX) above, advantageously a monomer M6 of formula (IX) in which Q1 represents H, n=0, Q2 is -CO-O-Q' and Q' represents an olefin.

[0515] According to this embodiment, preferably, the oligomeric side chains represent from 20% to 95% by weight relative to the total weight of copolymer A1.

[0516] According to a first preferred alternative form, the oligomeric side chains O1 comprising polyolefin segments represent from 20% to 70% by weight relative to the total weight of the copolymer A1.

[0517] According to a second preferred alternative, the oligomeric side chains O2 comprising at least repeating units of a monomer M2 corresponding to the general formula (II) and optionally repeating units of a monomer M1 corresponding to the general formula (I) and / or repeating units of a monomer M3 corresponding to the general formula (X) represent 30% to 95% by weight, relative to the total weight of the copolymer A1.

[0518] Preferably, the non-oligomeric side chains represent 5% to 80% by weight relative to the total weight of copolymer A1.

[0519] Preferably, the repeating unit of formula (X) is 2 to 50 wt % relative to the total moles of the monomers constituting copolymer A1.

[0520] Preferably, the repeating unit corresponding to the monomer M2 is 10 mol% to 90 mol%, preferably 30 mol% to 80 mol%, relative to the total moles of the monomers constituting the copolymer A1.

[0521] Preferably, the repeating unit corresponding to the monomer M1 is 1 mol % to 50 mol %, preferably 5 mol % to 30 mol %, relative to the total moles of the monomers constituting the copolymer A1.

[0522] When calculating the mol % of repeating units and / or monomers (e.g. M1, M2 or M3) relative to the total number of moles of monomers constituting copolymer A1, and when the copolymer comprises one or more than one side chain comprising a polyolefin type segment, the polyolefin segment is included by treating it as a single monomer (M6).

[0523] Method for obtaining polyglycol copolymer A1

[0524] A person skilled in the art can synthesize the polyglycol copolymer A1 with the aid of his common knowledge.

[0525] When the copolymers A1 are linear, they can be obtained according to the methods described in WO2015 / 110642, WO2015 / 110643 and WO2016113229, the synthesis of such copolymers A1 being described in the experimental part of these patent applications.

[0526] When the copolymers A1 are comb copolymers, they can be obtained according to the process described above for the copolymers A2 having borate functional groups.

[0527] ο Exogenous compound A4

[0528] According to one embodiment, the additive composition is a mixture of at least the following substances:

[0529] - Comb-type polyglycol copolymer A1,

[0530] a copolymer A2 comprising at least two borate functional groups and capable of associating with the polyglycol copolymer A1 by at least one transesterification reaction,

[0531] - Exogenous polyol compound A4.

[0532] Advantageously, according to this embodiment of the invention, the molar percentage of exogenous compound A4 in the additive composition relative to the borate functional groups of copolymer A2 is from 0.025% to 5000%, preferably from 0.1% to 1000%, more preferably from 0.5% to 500%, more preferably from 1% to 150%.

[0533] The exogenous polyol compound A4 is selected from polyglycols, in particular 1,2-diols and 1,3-diols, and glycerol derivatives. Within the meaning of the present invention, "exogenous compound" is understood to mean a compound which is added to the additive composition by mixing at least one comb-type polyglycol copolymer A1 and at least one compound A2, in particular a poly(borate) copolymer.

[0534] Compound A4 is chosen from organic compounds comprising at least one diol group and being compatible with use in the lubricating composition. Preferably, compound A4 is chosen from hydrocarbon compounds comprising from 2 to 30 carbon atoms.

[0535] Preferably, the exogenous compound A4 is chosen from lubricant additives, for example compounds known for the function of friction modifier, thickener, dispersant or detergent in lubricating compositions.

[0536] It is worth noting that the exogenous compound A4 can be selected from 1,2-diols and 1,3-diols and glycerol derivatives.

[0537] According to a preferred embodiment, the exogenous compound A4 may have the general formula (VI):

[0538]

[0539] in:

[0540] w3 is an integer equal to 0 or 1,

[0541] R 14 and R 15 are identical or different and are selected from -T, -CH2-OT and -CH2-OC(O)-T, T being selected from hydrogen or a hydrocarbon chain, preferably a linear alkyl chain having 1 to 24 carbon atoms, preferably 4 to 18 carbon atoms, preferably 6 to 12 carbon atoms.

[0542] "Hydrocarbon chain comprising 1 to 24 carbon atoms" is understood to mean a linear or branched alkyl or alkenyl group comprising 1 to 24 carbon atoms. Preferably, the hydrocarbon chain is a linear alkyl group. Preferably, it comprises 4 to 18 carbon atoms, preferably 6 to 12 carbon atoms.

[0543] In one embodiment, the exogenous compound A4 has the general formula (VI), wherein:

[0544]

[0545] -w3 is an integer equal to 0 or 1;

[0546] -R 14 and R 15 Different; R 14 or R 15 One of the groups is H, R 14 or R 15 Another of the groups is a hydrocarbon chain, preferably a linear alkyl group, having 1 to 24 carbon atoms, preferably 4 to 18 carbon atoms, preferably 6 to 12 carbon atoms.

[0547] In another preferred embodiment, the exogenous compound is selected from sugars and sugar derivatives.

[0548] A person skilled in the art is able to select sugars and sugar derivatives among sugars and sugar derivatives that are compatible with lubricating oils by virtue of his general knowledge.

[0549] The compound of formula (VI) is commercially available from the following suppliers: Alfa and

[0550] ο Exogenous compound A5

[0551] According to one embodiment, the additive composition is mixed with at least the following substances:

[0552] - Comb-type polyglycol copolymer A1,

[0553] a copolymer A2 comprising at least two borate functional groups and being able to associate with the comb-type polyglycol copolymer A1 by at least one transesterification reaction,

[0554] - an exogenous compound A5 selected from the compounds corresponding to formula (XI):

[0555]

[0556] in:

[0557] -Q represents a group selected from hydrocarbon radicals containing 1 to 30 carbon atoms, which are optionally substituted by one or more than one group selected from: hydroxyl or -OJ or -C(O)-OJ radicals, wherein J is a hydrocarbon radical containing 1 to 24 carbon atoms,

[0558] -G4 and G5 are the same or different and represent a group selected from a hydrogen atom, a hydrocarbon group containing 1 to 24 carbon atoms, a hydroxyl group or -OJ or -C(O)-OJ, wherein J is a hydrocarbon group containing 1 to 24 carbon atoms,

[0559] -g means 0 or 1.

[0560] Advantageously, the exogenous compound A5 corresponds to formula (XIIA):

[0561]

[0562] in:

[0563] - G1, G2, G3, G4 and G5 are the same or different and represent a group selected from a hydrogen atom, a hydrocarbon chain containing 1 to 24 carbon atoms, a hydroxyl group or -OJ or -C(O)-OJ, wherein J is a hydrocarbon group containing 1 to 24 carbon atoms,

[0564] -g means 0 or 1.

[0565] According to a preferred embodiment, the molar percentage of the exogenous compound A5 relative to the diol functional groups of the comb copolymer A1 is 0.025% to 5000%, preferably 0.1% to 1000%, more preferably 0.5% to 500%, more preferably 1% to 150%.

[0566] According to a preferred embodiment, the exogenous compound A5 is chosen from those corresponding to formula (XII B):

[0567]

[0568] According to yet another preferred embodiment, the exogenous compound A5 is selected from those corresponding to formula (XIIB), wherein g=0, G4=H, and G5 represents C1 to C 24 alkyl.

[0569] Through transesterification, the exogenous compound A5 releases in situ the diol fragment A6 of formula (XIII):

[0570]

[0571] Composition of the additive according to the invention:

[0572] The subject of the invention is a composition of associative and thermoreversibly exchangeable compounds, which is composed of at least the following substances:

[0573] - a polyglycol compound A1, in particular a polyglycol copolymer A1 as described above or in particular obtainable by one of the processes described above;

[0574] - a comb copolymer A2 comprising at least two borate functional groups.

[0575] Such a combination of additives makes it possible to control and adjust the rheological behavior of the medium to which the additives are added.The medium may be a hydrophobic, in particular a nonpolar medium, such as a solvent, a mineral oil, a natural oil or a synthetic oil.

[0576] Features of the novel additive composition of the present invention

[0577] Depending on the temperature and on the ratio of compounds A1, A2 and optionally A4 and / or A5 used, the additive compositions according to the invention exhibit very different rheological properties.

[0578] The above-mentioned polyglycol compound A1 and comb copolymer A2 show the advantage of associating and exchanging chemical bonds in a thermoreversible manner, especially in a hydrophobic medium, in particular in a non-polar hydrophobic medium.

[0579] Under certain conditions, the polyglycol compounds A1, in particular the polyglycol copolymers A1 and the comb copolymers A2 as defined above, can crosslink.

[0580] The polyglycol compound A1 and the comb copolymer A2 also exhibit the advantage of being interchangeable.

[0581] By "association" is understood a covalent chemical bond of the borate type which is established between the comb copolymer A2 comprising at least two borate functional groups and the polyglycol compound A1. Depending on the functionality of the polyglycol A1 and the comb copolymer A2 and the composition of the mixture, the formation of covalent bonds between the polyglycol A1 and the comb copolymer A2 having borate functional groups may or may not lead to the formation of a three-dimensional polymer network.

[0582] "Chemical bond" is understood to mean a covalent chemical bond of the borate ester type.

[0583] "Interchangeable" is understood to mean that the compounds are able to exchange chemical bonds with each other without changing the total number and type of chemical functional groups. The following reaction scheme 10 illustrates the exchange (ester exchange) chemical reaction:

[0584]

[0585] in

[0586] -R is a chemical group of the comb copolymer A2,

[0587] - the shaded circle represents the remainder of the chemical structure of the comb copolymer A2,

[0588] - The square rectangle represents the rest of the chemical structure of the polyglycol compound A1.

[0589] The borate bonds of copolymer A2, optionally formed by transesterification between the borate ester of copolymer A2 and exogenous compounds A4 and / or A5, and the borate bonds formed by association of polyglycol compound A1 and copolymer A2, can be exchanged with diol functional groups carried by compound A3 released in situ, optionally with diol functional groups carried by exogenous compounds A4 and / or A5, to form new borate esters and new diol functional groups without affecting the total number of borate functional groups and diol functional groups. Another process for exchanging chemical bonds is by continuous exchange of borate functional groups in the presence of diols, by metathesis reactions. Another process for exchanging chemical bonds is as follows Figure 3 As shown, it can be observed that the polyglycol copolymer A1-1 associated with polymer A2-1 has exchanged two borate bonds with borate copolymer A2-2. The polyglycol copolymer A1-2 associated with polymer A2-2 has exchanged two borate bonds with borate copolymer A2-1; the total number of borate bonds in the composition remains unchanged and is equal to 4. Copolymer A1-1 is then associated with polymer A2-2. Copolymer A1-2 is then associated with polymer A2-1. Copolymer A2-1 has exchanged with polymer A2-2.

[0590] "Crosslinking" is understood to mean a copolymer in the form of a network obtained by building bridges between the macromolecular chains of the copolymer. These interconnected chains are mostly distributed in three dimensions of space. Crosslinked copolymers form a three-dimensional network. In practice, the formation of a copolymer network is ensured by solubility tests. The formation of a copolymer network can be determined by placing the copolymer network in a solvent known to dissolve non-crosslinked copolymers of the same chemical substance. If the copolymer swells instead of dissolving, the person skilled in the art knows that a network has been formed. Figure 4Such a solubility test is described.

[0591] "Crosslinkable" is understood to mean a copolymer that is capable of crosslinking.

[0592] "Reversible crosslinking" is understood to refer to a crosslinked copolymer whose bridge is formed by a reversible chemical reaction. The reversible chemical reaction can be transferred in one direction or another, thereby causing a change in the polymer network structure. The copolymer can change from an initial non-crosslinked state to a crosslinked state (three-dimensional network of the copolymer), and can change from a crosslinked state to an initial non-crosslinked state. In the context of the present invention, the bridge formed between the chains of the copolymer is unstable. These bridges can be formed or exchanged by a reversible chemical reaction. In the context of the present invention, the reversible chemical reaction is an ester exchange reaction between the borate functional group of the copolymer (copolymer A2) and the diol functional group of the crosslinking agent (compound A1). The bridge formed is a borate type bond. Due to the reversibility of the ester exchange reaction, these borate bonds are covalent and unstable.

[0593] "Crosslinking in a thermoreversible manner" is understood to mean a copolymer that is crosslinked by means of a reversible reaction, the transfer of which in one direction or the other is controlled by temperature. Figure 5 At low temperature, the polyglycol compound A1 (composed of Figure 5 The copolymer with functional group A in the above formula is not represented by borate ester compound A2 (represented by Figure 5 The polyglycol copolymer A1 and the copolymer A2 containing at least two borate functional groups are then bound together and can be exchanged. Depending on the functionality of the polyglycol A1 and the copolymer A2 and on the composition of the mixture, a gel can be formed in the medium, in particular when the medium is non-polar. When the temperature is lowered again, the borate bonds between the polyglycol copolymer A1 and the copolymer A2 break and, if applicable, the composition loses its gelling properties.

[0594] A person skilled in the art can adjust the amount of borate ester bonds that can be formed between the comb-type polyglycol compound A1 and the copolymer A2 by appropriately selecting the polyglycol compound A1, the copolymer A2 and the composition of the mixture.

[0595] Furthermore, a person skilled in the art knows how to select the structure of copolymer A2 according to the structure of copolymer A1. Preferably, when copolymer A1 contains at least one monomer M1 with y=1, copolymer A2 containing at least one monomer M4 of formula (IV) with t=1 is preferred.

[0596] By controlling the degree of association of the polyglycol compound A1 and the copolymer A2, the viscosity and rheological behavior of the composition can be adjusted. When exogenous compounds A4 and / or A5 are present, the viscosity of the composition can be adjusted according to the temperature and the intended use.

[0597] In a preferred embodiment of the invention, the chemical substance of the exogenous compound A4 is identical to the chemical substance of the diol compound A3 released in situ by the transesterification reaction between the comb-type polydiol copolymer A1 and the compound A2 (in particular the polyboric acid ester copolymer). According to this embodiment, the total amount of free diols present in the composition is strictly greater than the amount of diol compounds released in situ. "Free diols" should be understood to mean diol functional groups that can form borate-type chemical bonds by transesterification. Within the meaning of the present patent application, "the total amount of free diols" should be understood to mean the total number of diol functional groups that can form borate-type chemical bonds by transesterification.

[0598] According to this embodiment, the total amount of free diols is always equal to the sum of the number of moles of exogenous polyol compound A4 and the number of diol functional groups (expressed in moles) of the polyglycol compound A1. In other words, if in the additive composition there are:

[0599] -i moles of exogenous polyol compound A4, and

[0600] -j moles of polyglycol compound A1,

[0601] (Thus, regardless of the degree of association between polyglycol copolymer A1 and poly(borate) copolymer A2) the total amount of free glycols will always be = i + j * average number of glycols per mole of compound A1 (in mol).

[0602] The amount of diol released in situ in the case of the transesterification reaction between A1 and A2 is equal to the number of boronate functions linking compounds A1 and A2.

[0603] A person skilled in the art knows how to select the chemical structure and amount of exogenous compounds A4 and / or A5 added to the additive composition according to the molar percentage of the borate functional groups of copolymer A2, so as to adjust the rheological behavior of the composition.

[0604] o Content of the compound of the lubricating composition

[0605] Advantageously, the content of compound A1 in the lubricating composition is from 0.05% to 20.0% by weight relative to the total weight of the composition, preferably from 0.5% to 10% by weight relative to the total weight of the lubricating composition.

[0606] Advantageously, the poly(borate) copolymer A2 is present in the lubricating composition in an amount ranging from 0.05% to 20.0% by weight relative to the total weight of the composition, preferably ranging from 0.25% to 10% by weight relative to the total weight of the lubricating composition.

[0607] Preferably, the weight ratio of the polyglycol compound A1 to the compound A2 in the composition (A1 / A2 ratio) is 0.005 to 200, preferably 0.05 to 20, and more preferably 0.1 to 10.

[0608] In one embodiment, the sum of the weights of compound A1 and comb copolymer A2 is from 0.01% to 40% relative to the total weight of the lubricating composition, advantageously from 0.75% to 20%, preferably from 2% to 15% relative to the total weight of the lubricating composition, and the weight of lubricating oil is from 60% to 99.9% relative to the total weight of the lubricating composition.

[0609] For engine applications, advantageously, the sum of the weights of compound A1 and comb copolymer A2 is between 0.1% and 15% relative to the total weight of the lubricating composition.

[0610] For transmission applications, advantageously, the sum of the weights of compound A1 and comb copolymer A2 is between 0.5% and 40% relative to the total weight of the lubricating composition.

[0611] In one embodiment, the molar percentage of exogenous compound A4 in the lubricating composition is 0.05% to 5000%, preferably 0.1% to 1000%, more preferably 0.5% to 500%, more preferably 1% to 150%, relative to the borate functional groups of the poly(borate) copolymer A2.

[0612] In one embodiment, the lubricating composition of the present invention is obtained by mixing:

[0613] - 0.05% to 20% by weight of at least one polyglycol compound A1 described above, relative to the total weight of the lubricating composition;

[0614] - 0.05% to 20% by weight, relative to the total weight of the lubricating composition, of at least one poly(borate) copolymer A2; and

[0615] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A4 described above, relative to the total weight of the lubricating composition;

[0616] - optionally, 0.001% to 0.5% by weight of at least one exogenous compound A5 as defined above, relative to the total weight of the lubricating composition; and

[0617] - 60% to 99.9% by weight of at least one lubricating oil as defined above, relative to the total weight of the lubricating composition;

[0618] In another embodiment, the lubricating composition of the present invention is obtained by mixing:

[0619] - 0.5 to 20% by weight of at least one polyglycol compound A1 described above, relative to the total weight of the lubricating composition;

[0620] - 0.25% to 20% by weight, relative to the total weight of the lubricating composition, of at least one poly(borate) copolymer A2; and

[0621] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A4 described above, relative to the total weight of the lubricating composition;

[0622] - optionally, 0.001% to 0.5% by weight of at least one exogenous compound A5 as defined above, relative to the total weight of the lubricating composition; and

[0623] - 0.5% to 15% by weight of at least one functional additive as defined above, relative to the total weight of the lubricating composition; and

[0624] - 60% to 99.25% by weight of at least one lubricating oil as defined above, relative to the total weight of the lubricating composition.

[0625] In one embodiment, the composition of the present invention is provided in the form of a parent composition. "Parent composition" should be understood to mean a composition that can be made into a daughter liquid by drawing out a certain amount of a mother liquid and supplementing it with a necessary amount of a diluent (solvent or other) to obtain a desired concentration. Thus, a daughter composition is obtained by diluting the parent composition.

[0626] The hydrophobic medium can be a solvent, mineral oil, natural oil or synthetic oil.

[0627] In one embodiment, the composition of the present invention may further comprise at least one additive selected from thermoplastics, elastomers, thermoplastic elastomers, thermosetting polymers, pigments, dyes, fillers, plasticizers, fibers, antioxidants, lubricant additives, compatibilizers, defoamers, dispersant additives, tackifiers and stabilizers.

[0628] Preparation method of the novel additive composition of the present invention

[0629] The novel additive composition of the present invention is prepared by methods well known to those skilled in the art. For example, it is sufficient, in particular for those skilled in the art, to carry out the following operations:

[0630] - taking out a desired amount of a solution containing the above-mentioned polyglycol compound A1;

[0631] - taking out a desired amount of a solution comprising the above-mentioned poly(borate) copolymer A2;

[0632] - optionally taking out a desired amount of a solution containing the above exogenous compound A4 and / or A5;

[0633] - Mixing the withdrawn solutions simultaneously or sequentially to obtain the composition of the invention.

[0634] The order of addition of the compounds has no influence on the performance of the process for the preparation of the additive composition.

[0635] Those skilled in the art also know how to adjust the various parameters of the composition of the present invention to obtain a composition in which the polyglycol compound A1 and the comb copolymer A2 having borate functional groups are associated or crosslinked, and the degree of association or crosslinking is adjusted at a given use temperature.

[0636] Use of the novel composition of the present invention

[0637] The composition of the invention can be used for all media whose viscosity varies with temperature. The composition of the invention makes it possible to thicken fluids and to adjust the viscosity according to the temperature of use. The additive composition according to the invention can be used for improvements in the fields of oil production, paper industry, paints, food additives or cosmetic or pharmaceutical preparations.

[0638] The lubricating composition according to the invention

[0639] Another subject of the present invention relates to a lubricating composition obtained by mixing at least the following substances:

[0640] - Lubricating oil, and

[0641] - the above-mentioned polyglycol compound A1,

[0642] a copolymer A2 as defined above, comprising at least two borate functional groups and capable of associating with said polyglycol compound A1 by at least one transesterification reaction,

[0643] - Optionally, an exogenous compound A4, in particular as defined above,

[0644] - Optionally, an exogenous compound A5 as defined above.

[0645] The preferences and definitions described in the general formulae (I), (Ia), (IA), (IB), (Ia-A), (Ia-B), (II-A), (II-B), (IX), (X) and (XII) also apply to the polyglycol compound A1 used in the lubricating composition of the present invention.

[0646] The preferences and definitions described for the general formulae (IV), (V), (IX) and (X) also apply to the borate copolymer A2 used in the lubricating composition of the invention.

[0647] Compared to the behavior of base oils and rheological additives of the polymer type of the prior art, the lubricating composition according to the invention has an opposite behavior with respect to temperature changes and exhibits the advantage that the rheological behavior can be adjusted according to the use temperature. Unlike base oils that become thinner when the temperature rises, the composition of the invention exhibits the advantage of becoming thicker when the temperature rises. The formation of reversible covalent bonds makes it possible to increase the molar mass of the polymer (reversibly), thereby limiting the decrease in the viscosity of the base oil at high temperatures. The supplementary addition of the diol compound makes it possible to control the rate of formation of these reversible bonds. Advantageously, the viscosity of the lubricating composition is thereby controlled and less dependent on temperature fluctuations. In addition, for a given use temperature, the viscosity of the lubricating composition and its rheological behavior can be adjusted by adjusting the amount of diol compound added to the lubricating composition. Finally, the lubricating composition of the invention has improved thermal stability, improved oxidation stability, improved viscosity index, improved cycle resistance and better reproducibility of performance qualities over time.

[0648] ο lubricating oil

[0649] "Oil" is understood to mean oil at ambient temperature (25°C) and atmospheric pressure (760 mm Hg, i.e. 10 5 Pa) is a fatty substance that is liquid below 4000 Pa.

[0650] "Lubricating oil" is understood to mean an oil that reduces friction between two moving parts to facilitate the operation of these parts. The lubricating oil may be of natural, mineral or synthetic origin.

[0651] The lubricating oil of natural origin may be oil of plant or animal origin, preferably oil of plant origin, such as rapeseed oil, sunflower oil, palm oil, coconut oil and the like.

[0652] Lubricating oils of mineral origin are of petroleum origin and are extracted from the petroleum fractions of atmospheric and vacuum distillation of crude oil. The distillation may be followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization, hydrofining, etc. By way of example, mention may be made of paraffinic mineral base oils, such as bright solvent (BSS) oils, naphthenic mineral base oils, aromatic mineral oils, hydrofined mineral base oils having a viscosity index of about 100, hydrocracked mineral base oils having a viscosity index of 120 to 130 or hydroisomerized mineral base oils having a viscosity index of 140 to 150.

[0653] As the name implies, lubricating oils of synthetic origin (or based on synthetic) come from chemical synthesis, such as the addition of a product to itself or to a polymerization, or the addition of a product to another product, such as esterification, alkylation, fluorination, etc., products deriving from components of petrochemicals, carbon chemistry and inorganic chemistry, such as: olefins, aromatic compounds, alcohols, acids, halogenated compounds, phosphorus compounds, silicon compounds, etc. By way of example, mention may be made of:

[0654] - synthetic oils based on synthetic hydrocarbons, for example poly(alpha-olefins) (PAOs), poly(internal olefins) (PIOs), polybutenes and polyisobutylenes (PIBs), alkylbenzenes or alkylated polyphenylenes;

[0655] - synthetic oils based on esters, for example esters of diacids or of neopolyols;

[0656] - synthetic oils based on polyethylene glycols, for example monoalkylene glycols, polyalkylene glycols and polyalkylene glycol monoethers;

[0657] - synthetic oils based on phosphate esters;

[0658] - Synthetic oils based on silicon derivatives, for example silicone oils or polysiloxanes.

[0659] The lubricating oil that can be used in the composition of the present invention can be selected from any oil of Group I to Group V specified in the API classification guide (Base Oil Interchangeability Guide of the American Petroleum Institute (API)) or equivalent standards according to ATIEL (European Technical Association of the Lubricant Industry)), which are summarized as follows:

[0660]

[0661] *Measured according to standard ASTM D2007

[0662] **Measured according to standards ASTM D2622, ASTM D4294, ASTM D4927 and ASTM D3120

[0663] ***Measured according to standard ASTM D2270

[0664] The composition of the present invention may contain one or more than one lubricating oil. The lubricating oil or lubricating oil mixture is the main component in the lubricating oil composition. Then, a lubricating base oil is used. The main component is understood to mean that the lubricating oil or lubricating oil mixture is at least 51% by weight of the total weight of the composition.

[0665] Preferably, the lubricating oil or lubricating oil mixture is at least 70 wt % of the total weight of the composition.

[0666] In one embodiment of the present invention, the lubricating oil is selected from one of the oils of Group I, Group II, Group III, Group IV or Group V of the API classification and mixtures thereof. Preferably, the lubricating oil is selected from the oils of Group III, Group IV or Group V of the API classification and mixtures thereof. Preferably, the lubricating oil is an oil of Group III of the API classification.

[0667] The lubricating oil has a kinematic viscosity at 100° C. measured according to standard ASTM D445 of 2 cSt to 150 cSt, preferably 2 cSt to 15 cSt.

[0668] ο Functional additives

[0669] In one embodiment, the composition of the present invention may further comprise one or more functional additives selected from the group consisting of detergents, anti-wear additives, load-bearing additives, antioxidants, polymers for improving viscosity index, pour point improvers, defoamers, thickeners, anti-corrosion additives, dispersants, friction modifiers, and mixtures thereof.

[0670] The functional additives added to the composition of the present invention are selected according to the final use of the lubricating composition. These additives can be introduced in two different ways:

[0671] - each additive is added to the composition individually and sequentially,

[0672] - or all additives are added to the composition simultaneously; in this case, the additives are usually available in the form of packets, called additive packages.

[0673] When a functional additive or a mixture of functional additives is present, it is present in an amount ranging from 0.1% to 10% by weight relative to the total weight of the composition.

[0674] Detergent:

[0675] These additives reduce the formation of deposits on the surface of metal parts by dissolving oxidation by-products and combustion by-products. Detergents that can be used in the lubricating composition according to the present invention are well known to those skilled in the art. The detergents commonly used in the formulation of lubricating compositions are generally anionic compounds containing long lipophilic hydrocarbon chains and hydrophilic heads. The associated cations are generally metal cations of alkali metals or alkaline earth metals. The detergent is preferably selected from alkali metal or alkaline earth metal salts of carboxylic acids, sulfonic acids, salicylic acids, cyclohexane acids and phenols. Alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium or barium. These metal salts may contain approximately stoichiometric amounts or excess (greater than stoichiometric amounts) of metal. In the latter case, "high alkalinity" detergents must be treated. The excess metal that makes the detergent high alkalinity is provided in the form of an oil-insoluble metal salt, such as a carbonate, hydroxide, oxalate, acetate or glutamate, preferably a carbonate.

[0676] Anti-wear additives and load-carrying additives:

[0677] These additives protect surfaces from friction by forming a protective film adsorbed on these surfaces. There are a wide variety of anti-wear additives and supported additives. Mention may be made, by way of example, of phosphorus / sulfur additives, such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, more particularly zinc dialkyldithiophosphates or ZnDTP, amine phosphates, polysulfides, in particular sulfur-based olefins and metal dithiocarbamates.

[0678] Antioxidants:

[0679] These additives slow down the degradation of the composition. The degradation of the composition can be reflected by the formation of sediments, the presence of sludge or an increase in the viscosity of the composition. Antioxidants act as free radical inhibitors or destroyers of hydrogen peroxide. Commonly used antioxidants include phenolic or aminic antioxidants.

[0680] Anti-corrosion additives:

[0681] These additives cover the surface with a film that prevents oxygen from entering the metal surface. They can sometimes neutralize acids or certain chemical products to prevent metal corrosion. For example, mention can be made of dithiothiadiazole (DMTD), benzotriazole or phosphites (which capture free sulfur).

[0682] Viscosity Index Improving Polymers:

[0683] These additives can ensure good cold resistance and a minimum viscosity of the composition at high temperatures. Mention may be made, by way of example, of polymer esters, olefin copolymers (OCP) or polymethacrylates (PMA).

[0684] Pour point improvers:

[0685] These additives improve the cold properties of the composition by slowing down the formation of paraffin crystals. These are, for example, polyalkyl methacrylates, polyacrylates, polyarylamide, polyalkylphenols, polyalkylnaphthalenes and alkylated polystyrenes.

[0686] Defoaming agent:

[0687] These additives have the effect of counteracting the action of the detergents. By way of example, mention may be made of polydimethylsiloxanes and polyacrylates.

[0688] Thickener:

[0689] Thickeners are additives used in particular in industrial lubrication and make it possible to formulate lubricants of higher viscosity than engine lubricating compositions. By way of example, mention may be made of polyisobutylenes having a weight-average molar mass of 10 000 to 100 000 g / mol.

[0690] Dispersants:

[0691] These additives ensure the maintenance in suspension and the removal of insoluble solid contaminants consisting of oxidation by-products formed during use of the composition. Mention may be made, by way of example, of succinimide, PIB (polyisobutylene) succinimide and Mannich bases.

[0692] Friction modifiers:

[0693] These additives improve the friction coefficient of the composition. Mention may be made, by way of example, of molybdenum dithiocarbamates, amines having at least one hydrocarbon chain of at least 16 carbon atoms, esters of fatty acids and of polyols, for example esters of fatty acids and of glycerol, in particular glycerol monooleate.

[0694] Preparation method of the lubricating composition of the present invention

[0695] The lubricating composition of the invention is prepared by methods well known to those skilled in the art. For example, it is sufficient, in particular for those skilled in the art, to carry out the following operations:

[0696] - taking out a desired amount of a solution containing the above-mentioned polyglycol compound A1;

[0697] - taking out a desired amount of a solution comprising the above-mentioned poly(borate) copolymer A2;

[0698] -optionally taking out a desired amount of a solution containing the exogenous compound A4;

[0699] - The withdrawn solution is mixed simultaneously or sequentially in a lubricating base oil to obtain the lubricating composition of the present invention.

[0700] The order of addition of the compounds has no influence on the performance of the process for the preparation of the lubricating composition.

[0701] Properties of the lubricating composition according to the invention

[0702] The lubricating compositions of the invention result from the mixing of associative polymers which exhibit the property of increasing the viscosity of the lubricating oil by association. The lubricating compositions according to the invention have the advantage that these associations or crosslinks are thermally reversible and, optionally, the extent of association or crosslinking can be controlled by adding supplementary diol compounds. In addition, they exhibit improved thermal stability, improved viscosity index, improved oxidation stability, improved cycling performance and better reproducibility of performance qualities over time.

[0703] A person skilled in the art knows how to adjust the different parameters of the different components of the composition in order to obtain a lubricating composition whose viscosity increases when the temperature rises and to adjust its viscosity and rheological behavior.

[0704] ο Method for adjusting the viscosity of lubricating compositions

[0705] Another subject of the present invention is a method for adjusting the viscosity of a lubricating composition, comprising at least:

[0706] - providing a lubricating composition obtained by mixing at least one lubricating oil, at least one polyglycol compound A1 and at least one copolymer A2, wherein the copolymer A2 comprises at least two borate functional groups and can associate with the polyglycol compound A1 by at least one transesterification reaction,

[0707] - Optionally, adding at least one exogenous compound A4 to the lubricating composition,

[0708] Optionally, at least one exogenous compound A5 selected from boric acid diesters and boric acid triesters is added to the lubricating composition.

[0709] Within the meaning of the present invention, "adjusting the viscosity of the lubricating composition" is understood to mean adapting the viscosity at a given temperature according to the use of the lubricating composition. This can be obtained by adding the above-mentioned exogenous compounds A4 and / or A5. These compounds make it possible to control the degree of association and crosslinking of the two polyglycol A1 and poly(borate) A2 compounds. This method is described in detail in WO2016 / 113229.

[0710] Other subjects according to the invention:

[0711] Another subject of the present invention is the use of the lubricating composition described above for lubricating machine parts.

[0712] In the remainder of the description, percentages are expressed by weight relative to the total weight of the lubricating composition.

[0713] The composition of the present invention can be used to lubricate the surfaces of parts typically present in an engine, such as the surfaces of pistons, rings, and bushing systems.

[0714] Therefore, another subject of the present invention is a composition for lubricating at least an engine, said composition comprising, in particular consisting essentially of, a composition obtained by mixing:

[0715] - 85% to 99.9% by weight, advantageously 92% to 99% by weight, of lubricating oil, and

[0716] - 0.1% to 15% by weight, advantageously 1% to 8% by weight, of a mixture of at least one of the abovementioned compounds A1 and at least one of the abovementioned borate copolymers A2; and

[0717] - Optionally, 0.001% to 0.1% by weight of at least one exogenous compound A4 as described above;

[0718] - Optionally, 0.001% to 0.1% by weight of at least one exogenous compound A5 as described above;

[0719] The kinematic viscosity of the composition at 100° C., measured according to standard ASTM D445, is between 3.8 cSt and 26.1 cSt; expressed as a weight percentage relative to the total weight of the composition.

[0720] In the composition for lubricating at least one of the above-mentioned engines, the compounds A1 and the borate comb copolymers A2 as defined above can associate and exchange in a thermoreversible manner, in particular in the presence of exogenous compounds A4 and / or exogenous compounds A5, but they do not form a three-dimensional network. They are not crosslinked.

[0721] In one embodiment of the present invention, at least the composition for lubricating an engine comprises, in particular essentially consists of, a composition obtained by mixing:

[0722] - 80% to 99% by weight of lubricating oil, and

[0723] - 0.1 to 15% by weight of a mixture of at least one of the abovementioned copolymers A1 and at least one of the abovementioned borate copolymers A2; and

[0724] - Optionally, 0.001% to 0.1% by weight of at least one exogenous compound A4 as described above;

[0725] - 0.5 to 15% by weight of at least one functional additive selected from detergents, antiwear additives, load-bearing additives, other antioxidants, anticorrosive additives, polymers that increase the viscosity index, pour point improvers, defoamers, thickeners, dispersants, friction modifiers, and mixtures thereof;

[0726] The kinematic viscosity of the composition at 100° C., measured according to standard ASTM D445, is between 3.8 cSt and 26.1 cSt; expressed as a weight percentage relative to the total weight of the composition.

[0727] The definitions and preferences concerning lubricating oil, comb copolymer A1, borate copolymer A2 and exogenous compounds A4 and / or A5 also apply at least to the composition for lubricating an engine.

[0728] Another subject of the invention is a composition for lubricating at least a transmission, for example a manual transmission or an automatic transmission.

[0729] Therefore, another subject of the present invention is a composition at least for lubricating a transmission, said composition comprising, in particular consisting essentially of, a composition obtained by mixing:

[0730] - 50% to 99.5% by weight of lubricating oil, and

[0731] - 0.5 to 50% by weight of a mixture of at least one of the abovementioned compounds A1 and at least one of the abovementioned borate copolymers A2; and

[0732] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A4 as described above;

[0733] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A5 as described above;

[0734] The kinematic viscosity of the composition at 100° C., measured according to standard ASTM D445, is between 4.1 cSt and 41 cSt, expressed as a weight percentage relative to the total weight of the composition.

[0735] In one embodiment of the present invention, at least the composition for lubricating a transmission comprises, in particular essentially consists of, a composition obtained by mixing:

[0736] - 45% to 99.39% by weight of lubricating oil, and

[0737] - 0.5 to 50% by weight of a mixture of at least one of the above-mentioned comb copolymers A1 and at least one of the above-mentioned borate copolymers A2; and

[0738] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A4 as described above;

[0739] - Optionally, 0.001% to 0.5% by weight of at least one exogenous compound A5 as described above;

[0740] - 0.1 wt % to 15 wt % of at least one functional additive selected from detergents, antiwear additives, load-bearing additives, other antioxidants, anticorrosive additives, polymers that increase viscosity index, pour point improvers, defoamers, thickeners, dispersants, friction modifiers and mixtures thereof;

[0741] The kinematic viscosity of the composition at 100° C., measured according to standard ASTM D445, is between 4.1 cSt and 41 cSt, expressed as a weight percentage relative to the total weight of the composition.

[0742] The definitions and preferences with regard to lubricating oil, copolymer A1, borate copolymer A2 and exogenous compounds A4 and A5 also apply at least to the composition for lubricating a transmission.

[0743] The composition of the present invention can be used in engines or transmissions of light vehicles, heavy vehicles and ships.

[0744] Another subject of the invention is a method for lubricating at least one machine component, in particular at least one engine or at least one transmission, comprising a phase in which the machine component is brought into contact with at least one lubricating composition as described above.

[0745] The definitions and preferences with respect to the lubricating oil, copolymer A1, borate copolymer A2 and, if applicable, exogenous compounds A4 and A5 also apply to the method for lubricating at least machine parts.

[0746] The various embodiments, alternatives, preferences and advantages described above for each subject matter of the present invention are applicable to all subjects of the present invention and may be employed individually or in combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0747] Figure 1 The diagram shows a random copolymer (P1), a gradient copolymer (P2) and a block copolymer (P3); each circle represents a monomer unit. The differences in chemical structure between monomers are represented by different colors (light grey / black).

[0748] Figure 2 Schematic representation of a comb copolymer.

[0749] Figure 3 Schematic representation of the boronate ester bond exchange reaction between two polydiol polymers (A1-1 and A1-2) and two boronate ester polymers (A2-1 and A2-2) in the presence of diols.

[0750] Figure 4 The diagram shows the crosslinking of a composition according to the invention in tetrahydrofuran (THF).

[0751] Figure 5 The diagram shows the behavior of the composition of the invention as a function of temperature. The copolymer (2) with diol functional groups (functional group A) can be associated with the copolymer (1) with borate functional groups (functional group B) in a thermoreversible manner by transesterification. The organic radical of the borate functional group (functional group B) exchanged during the transesterification reaction is the diol represented by the black crescent symbol. A borate-type chemical bond (3) is formed, releasing the diol compound.

[0752] Fig. 6A , Figure 6B and Figure 6C Different comb copolymers A2 are indicated.

[0753] Figure 7 Shown is a scheme for the synthesis of comb copolymer A2.

[0754] Figure 8 Shown is a scheme for the synthesis of comb copolymer A2.

[0755] Fig. 9 is a graph reporting the relative viscosity (ordinate) of compositions A, B and C as a function of temperature (abscissa) from 10°C to 150°C.

[0756] Fig.10 Represents a graph reporting the relative viscosity (ordinate) of composition B and Bd (obtained from composition B by diluting composition B to 2.10% by weight of the copolymer) as a function of temperature (abscissa) between 10°C and 150°C.

[0757] Fig.11 is a graph showing the relative viscosity (ordinate) of composition Bd as a function of temperature (abscissa) from 10°C to 150°C during three consecutive heating-cooling cycles (Bd-1, Bd-2 and Bd-3).

[0758] Fig.12 is a graph showing the relative viscosity (ordinate) of composition C as a function of temperature (abscissa) from 10°C to 150°C during three consecutive heating-cooling cycles (C-1, C-2 and C-3).

[0759] Fig.13 It is a graph showing the relative viscosity of composition D (ordinate) as a function of temperature (abscissa) from 10°C to 150°C.

[0760] The invention is illustrated by the following non-limiting examples.

[0761] Experimental part:

[0762] In the examples, parts and percentages are expressed by weight unless otherwise indicated.

[0763] 1 Synthesis of comb-type copolymer A2 with borate functional groups

[0764] ο1.1: Synthesis of monomers

[0765] 1.1.1 Synthesis of brominated monomers (branched monomers):

[0766]

[0767] Scheme 11: Synthesis of brominated monomers

[0768] 7ml of hydroxyethyl methacrylate (58mmol), 5.4ml of pyridine (66mmol) and 75ml of dichloromethane were introduced into a 250ml round-bottom flask. The round-bottom flask was then closed using a septum, degassed by bubbling with N2 for 30 minutes, and then placed in an ice-cold water bath. 7.7ml of 2-bromo-2-methylpropionyl bromide (64mmol) was subsequently added dropwise to the reaction mixture over approximately 15 minutes. The round-bottom flask was kept stirring for 6 hours. A white precipitate was formed during the reaction. The solution was then filtered to remove the solid. The solid was rinsed with dichloromethane (2×10ml). The organic phase was then washed twice with 100ml of distilled water, washed twice with 100ml of 10% NaHCO3 solution, and then washed twice with 100ml of saturated NaCl solution. The organic phase was then dried with MgSO4, and a rotary evaporator was used to remove the solvent. 11.6g of bright yellow liquid (yield = 72%) was obtained.

[0769] 1 H NMR (CDCl3): δ: 6.05ppm (m, 1H), 5.52ppm (m, 1H), 4.35ppm (m, 4H), 1.87ppm (m, 3H), 1.85ppm (s, 6H).

[0770] 1.1.2 Synthesis of methacrylic acid olefin macromonomer (monomer M6-A):

[0771]

[0772] Scheme 12: Synthesis of olefinic monomers

[0773] 58.8 g (11.6 mmol) of Krasol HLBH 5000M (provided by Cray Valley) was dissolved in 150 g of dichloromethane (DCM). Subsequently, 11.9 g of methacrylic anhydride (77.3 mmol), 56.2 mg of 4-dimethylaminopyridine (0.47 mmol) and 7.37 g of trimethylamine (76 mmol) were added. The solution was stirred at ambient temperature for 24 hours. The solution was then washed twice with a 0.5 M aqueous sodium hydroxide solution, then twice with a 0.5 M aqueous hydrochloric acid solution, and finally twice with distilled water. The organic phase was dried over MgSO4, and the solvent was then evaporated using a rotary evaporator. The product was then dissolved in tetrahydrofuran (THF) and then precipitated three times continuously from acetone (dissolved in THF before each precipitation). The product was dried at 50°C under vacuum for 18 hours. A colorless, transparent, viscous liquid was thus obtained. By 1 1H NMR confirmed the quantitative functionalization of Krasol (alcohol used to generate the methacrylate) by the complete disappearance of the peak between 3.8 ppm and 4.1 ppm, which is characteristic of protons in the alpha position relative to the Krasol alcohol functionality.

[0774] 1 H NMR (CDCl3): δ: 6.05 ppm (m, 1H), 5.52 ppm (m, 1H), 5.1-4.9 ppm (m, 1H), 1.94 ppm (s, 3H), 2.05-0.48 ppm (1020H), traces of DCM (5.29 ppm), THF (3.75 ppm; 1,84 ppm) and acetone (2.17 ppm).

[0775] 1.1.3 Synthesis of olefin macromonomer with terminal styrene functional group (monomer M6-B-OLF1500-St)

[0776] The synthesis of olefin macromonomers with terminal styrene functional groups (OLF1500-St) was carried out in two stages according to the following scheme (Schemes 14 and 15):

[0777] Phase 1

[0778] 4.0 g (27 mmol) of 4-vinylbenzoic acid (4-VBA) was dissolved in 110 ml of anhydrous dichloromethane (DCM), and a catalytic amount (15 drops) of anhydrous dimethylformamide (DMF) was added. Subsequently, 5.8 ml (67 mmol) of oxalyl chloride was added to the solution. The reaction mixture was stirred at ambient temperature for 2 hours. After the solvent was evaporated under reduced pressure, the yellow liquid obtained was dried under vacuum for 2 hours.

[0779] Phase 2:

[0780] 2.64 g (1.76 mmol) of an olefin copolymer OLF1500 with a number average molar mass Mn of 1500 g / mol and a terminal primary alcohol functional group and 3.8 ml (27.5 mmol) of NEt3 were dissolved in 50 ml of anhydrous DCM, and the mixture was cooled to about 0 ° C using an ice bath. Subsequently, a solution of 4-vinylbenzoyl chloride (27 mmol) obtained in the first stage in 30 ml of DCM was added dropwise to the reaction mixture in about 25 minutes. The mixture was stirred in an ice bath for 1 hour, and then stirred at ambient temperature for 24 hours. Excess 4-vinylbenzoyl chloride was neutralized by adding 10 ml of water and stirring the reaction mixture for 1 hour. Subsequently, the reaction mixture was washed with 3 × 100 ml of 1M HCl solution, 2 × 100 ml of 1M NaOH solution and 1 × 100 ml of sodium chloride aqueous solution in sequence. After drying the organic phase with MgSO4, the transparent yellow solution obtained was filtered through a basic alumina column. Evaporation of DCM and drying in vacuo gave 2.80 g (97.6%) of a light yellow oil with the following characteristics:

[0781] 1 H NMR (400 MHz, CDCl3) δ: 8.00 (multiplet, 2H), 7.46 (split doublet, J=1.5 Hz and J=8.3 Hz, 2H), 6.75 (split doublet, J=12.0 Hz and J=17.5 Hz, 1H), 5.86 (split doublet, J=0.8 Hz and J=17.7 Hz, 1H), 5.38 (doublet, J=11.0 Hz, 1H), 4.41-4.28 (multiplet, 2H), 1.83-0.52 (multiplet, 961H).

[0782] 1.1.4. Synthesis of boric acid esters condensed from 1,2-dodecanediol monomer (B-C12Em)

[0783] This monomer was obtained according to the protocol described in application WO 2016 / 113229 (experimental part §2.1).

[0784] ο 1.2: Synthesis of copolymers - methods

[0785] Number average molar masses and dispersities were obtained by size exclusion chromatography using poly(methyl methacrylate) calibration and THF as eluent.

[0786] 1.2.1 Synthesis of brominated backbone (brominated backbone 1) :

[0787]

[0788] 0.50 g (1.8 mmol) of the brominated monomer obtained according to the scheme described in step 1.1.1 (Scheme 11) above, 8.52 g (59.9 mmol) of butyl methacrylate, 1.14 g (11.0 mmol) of styrene, 35.8 mg (0.13 mmol) of cumyl dithiobenzoate, 6.3 mg (0.04 mmol) of azobisisobutyronitrile (AIBN) and 5 g of anisole were introduced into a 50 ml Schlenk tube. The reaction medium was stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 16 hours. The polymer was subsequently isolated by three consecutive precipitations from methanol and then dried under vacuum at 50° C. for 16 hours. The number average molar mass (M n ) is 38000g / mol, and the dispersion The number average degree of polymerization (DP n ) is about 300. The polymer thus obtained contains about 2.3 mol% (about 5 wt%) of bromomethylacrylate monomer. These values ​​were obtained by size exclusion chromatography, using THF as eluent and polymethyl methacrylate (PMMA) calibration and by monitoring the conversion of the monomers during the copolymerization.

[0789] 1.2.2 Synthesis of dithiobenzoate backbone

[0790]

[0791] Solution 13

[0792] 835 mg of the brominated backbone 1 obtained according to the above protocol (§1.2.1) (141 μmol of brominated monomer), 43.6 mg of bis(thiobenzoyl) disulfide (142 μmol), 10 mg of copper(I) bromide (CuBr) (69 μmol), 29 mg of copper powder (456 μmol) and 20 g of toluene were introduced into a 100 ml Schlenk round-bottom flask. The round-bottom flask was then sealed airtight using a septum. At the same time, a solution containing 2 ml of toluene and 26 mg of N,N,N',N",N"-pentamethyldiethylenetriamine (150 μmol) was prepared in an airtightly sealed sample tube. The flask and sample tube were degassed by bubbling nitrogen through the solution for 30 minutes. The solution contained in the sample tube was then taken out and injected into the round-bottom flask using a syringe. The round-bottom flask was placed in an oil bath thermostatically controlled at 80°C for 3 days. The solution was then filtered through a basic alumina column to remove copper and then concentrated using a rotary evaporator. Finally, the polymer was isolated by three consecutive precipitations from methanol and then dried in vacuo at 50 °C for 20 h. The number average molar mass M n is 44000g / mol and the dispersion These values ​​were obtained by size exclusion chromatography using THF as eluent and PMMA.

[0793] 1.2.3 Synthesis of comb-type poly(borates) (PBB1) via RAFT

[0794]

[0795] 220 mg (39 μmol of dithiobenzoate monomer) of the dithiobenzoate backbone 1 obtained according to the protocol described in §1.2.2, 5.71 g (16.9 mmol) of octadecyl methacrylate, 0.79 g (1.5 mmol) of borate monomer obtained according to the protocol described in patent application WO2016 / 113229 (experimental part §2.1), 1.72 mg (10.5 μmol) of AIBN and 7 g of anisole were introduced into a 50 ml Schlenk tube. The reaction medium was stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 8.5 hours. Finally, the polymer was isolated by three consecutive precipitations from anhydrous acetone and then dried in vacuo at 50° C. for 20 hours. The number average molar mass M was obtained. n is 137000g / mol and the dispersion The copolymer has a molecular weight of 2.4. These values ​​were obtained by size exclusion chromatography using THF as eluent and PMMA calibration. 1 The monomer conversion determined by H NMR and the number average degree of polymerization (DP) of the side chains n About 165.

[0796] 1.2.4 Synthesis of butyl methacrylate, with boric acid-C 12 Ester-functional styrene and olefin macromonomers Comb copolymer of M6-B-OLF1500-St (PBB2)

[0797]

[0798] Solution 14

[0799] The synthesis of the comb copolymer PBB2 with borate functional groups in the main chain was carried out according to the following scheme:

[0800] 2.50 g (17.5 mmol) of butyl methacrylate (BMA), 0.39 g (0.87 mmol) of 1,2-dodecanediol monomer (mEB-C) obtained according to the protocol described in application WO2016 / 113229 (experimental part §2.1) were added. 12) condensed boric acid ester, 0.89 g (0.93 mmol) of olefin macromonomer M6-B-OLF1500-St obtained according to the protocol described in Section 1.1.3, 9.3 mg (0.04 mmol) of RAFT transfer agent 2-cyano-2-propylphenyl dithioate (PPBD), 2.8 mg (0.02 mmol) of AIBN and 3.8 ml of anisole were introduced into a 25 ml Schlenk tube. The reaction medium was stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 19 hours.

[0801] After 19 hours of polymerization, the Schlenk tube was placed in an ice bath to stop the polymerization. The polymer was then isolated by precipitation from acetone cooled in an ice bath, separation was performed by settling the supernatant, and the pasty polymer phase was dried overnight at 50° C. in a vacuum. The number average molar mass (M) of the copolymer thus obtained was n ) is 54800 g / mol, and the dispersion The number average degree of polymerization (DP n ) is 280. The first two values ​​were obtained by size exclusion chromatography using THF as eluent and poly(methyl methacrylate) calibration, while DP n pass 1 The conversion of monomers during the polymerization process was monitored by H NMR.

[0802] Obtain poly(butyl methacrylate-co-EB-C 12 -co-OLF1500OCP) copolymer PBB2, which contains 5.7 mol% EB-C 12 repeat units (12 wt%) and 6.8 mol % of side chain OLF1500-OCP repeat units (30 wt%).

[0803] 1.2.5 Synthesis of butyl methacrylate, olefin macromonomer M6-B-OLF1500-St and poly(boric acid ester) polymer Comb-type copolymer with side chains (PBB3)

[0804] The synthesis of the comb copolymer (PBB3) containing the olefin macromonomer M6-B-OLF1500-St and the poly(boronate) polymer side chains was carried out according to the following scheme (Scheme 15 below):

[0805]

[0806] Solution 15

[0807] 1.2.5.1 Synthesis of olefin macromonomer M6-B-OLF1500-St and ethyl methacrylate 2-xanthate Ester backbone (M6-B-OLF1500-St-co-xanthate backbone)

[0808] 4.00 g (28.1 mmol) of butyl methacrylate, 1.30 g (1.36 mmol) of olefin macromonomer M6-B-OLF1500-St, 1.06 g (4.52 mmol) of ethyl methacrylate 2-xanthate (XEMA; according to "Synthesis of Well-Defined Polythiol Copolymers by RAFT Polymerization", R. Macromolecules, 2012, 45, 821-827, 16.4 mg (0.074 mmol) of RAFT transfer agent 2-cyano-2-propylbenzodithioester (PPBD), 4.8 mg (0.030 mmol) of azobisisobutyronitrile (AIBN) and 6.4 ml of anisole were introduced into a 50 ml Schlenk tube. The reaction medium was stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 20.5 hours.

[0809] After 20.5 hours of polymerization, the Schlenk tube was placed in an ice bath to stop the polymerization. The polymer was then separated by two consecutive precipitations from methanol cooled in an ice bath, filtered and dried overnight at 50° C. under vacuum. The number average molar mass (M) of the copolymer thus obtained was n ) is 80600g / mol, and the dispersion The number average degree of polymerization (DP n ) is 350. The first two values ​​were obtained by size exclusion chromatography using THF as eluent and poly(methyl methacrylate) calibration, while DP n pass 1 The conversion of monomers during the polymerization process was monitored by H NMR.

[0810] A poly(butyl methacrylate-co-2-xanthate ethyl methacrylate-co-M6-B-OLF1500-St) copolymer, "M6-B-OLF1500-St-xanthate backbone", was obtained containing 7.9 mol% of ethyl methacrylate 2-xanthate repeating units (9.5 wt%) and 5.6 mol% of OLF1500-OCP side chains (27 wt%).

[0811] 1.2.5.2 Synthesis of the backbone containing olefin macromonomer M6-B-OLF1500-St and acrylate side chain functional groups (M6-B-OLF1500-St-Acrylate Main Chain)

[0812] The xanthate functionality of the "M6-B-OLF1500-St-co-xanthate backbone" copolymer was subsequently converted to acrylate via a Michael addition reaction with 1,6-hexanediol diacrylate according to the following scheme:

[0813] 3.70 g (1.50 mmol XEMA functional groups) of "M6-B-OLF1500-St-co-xanthate backbone" were introduced into a 250 ml Schlenk tube and dissolved in 35 ml of a mixture of THF:DMF=1:1 (volume ratio). 0.44 g (6.00 mmol) of n-butylamine and three drops of tributylphosphine were introduced into the Schlenk tube. The reaction medium was degassed for 10 minutes by bubbling nitrogen and then stirred at ambient temperature for 2 hours. Subsequently, a solution of 6.79 g (30.0 mmol) of 1,6-hexanediol diacrylate in 3 ml THF was introduced, and the reaction medium was stirred at ambient temperature for 48 hours.

[0814] The reaction medium is subsequently concentrated under vacuum and the polymer is isolated by three consecutive precipitations using methanol cooled in an ice bath, filtered and dried overnight under vacuum at 50° C. The number-average molar mass (M n ) is 60100 g / mol, and the dispersion is 1.65, which was obtained by size exclusion chromatography using THF as eluent and poly(methyl methacrylate) calibration.

[0815] pass 1 H NMR analysis revealed a "M6-B-OLF1500-St-acrylate backbone" copolymer containing 5.1 mol % repeating units with pendant acrylate functional groups (9.4 wt %) and 5.6 mol % OLF1500-OCP side chains (27 wt %).

[0816] 1.2.5.3 Produced by methacrylic acid according to the protocol described in application WO 2016 / 113229 (experimental part §2.1) Lauryl ester and 1,2-dodecanediol (mEB-C 12 ) condensed borate monomers to synthesize side chain precursors (poly(borane) Acid ester) side chain)

[0817] The poly(borate) polymer side chains of the comb copolymer containing the olefin macromonomer M6-B-OLF1500-St and the poly(borate) polymer side chains (PBB3) were prepared according to the following scheme (Scheme 15 above):

[0818] 5.00 g (19.6 mmol) of lauryl methacrylate (LMA), 2.20 g (4.91 mmol) of 1,2-dodecanediol ( mE BC 12 ) condensed boronate monomer, 155 mg (0.70 mmol) of RAFT transfer agent PPBD, 5.8 mg (0.035 mmol) of AIBN and 2.0 ml of anisole were introduced into a 25 ml Schlenk tube. The reaction medium was stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 24 hours.

[0819] After 24 hours of polymerization, the Schlenk tube was placed in an ice bath to stop the polymerization. The polymer was then isolated by precipitation from acetone cooled in an ice bath, separation was performed by settling the supernatant, and the polymer phase was dried overnight at 50° C. in a vacuum. The number average molar mass (M) of the copolymer thus obtained was n ) is 10700 g / mol, and the dispersion The number average degree of polymerization (DP n ) is 26. The first two values ​​were obtained by size exclusion chromatography using THF as eluent and poly(methyl methacrylate) calibration, while DP n pass 1 The conversion of monomers during the polymerization process was monitored by H NMR.

[0820] A repeating unit mEB-C containing 21 mol% was obtained. 12 (32 wt%) and 79 mol% of lauryl methacrylate repeating units (68 wt%) of poly(lauryl methacrylate-co-EB-C 12 ) copolymer "poly(borate) side chains".

[0821] 1.2.5.4 Synthesis of poly(boronate) polymers containing olefin macromonomer M6-B-OLF1500-St and side chains Comb copolymer (PBB3)

[0822] 145 g (0.015 mmol) of the "poly (boronate) side chain" copolymer prepared according to the protocol described in 1.2.5.3 was introduced into a 25 ml Schlenk tube and dissolved in 2.0 ml of a mixture of THF:DMF=2:1 (volume ratio). 5 mg (0.06 mmol) of n-butylamine and three drops of tributylphosphine were added to the solution. The reaction medium was degassed for 3 minutes by bubbling nitrogen and stirred at ambient temperature for 2 hours. Subsequently, under a nitrogen atmosphere, a solution of 200 mg (0.05 mmol of acrylate functional groups) of the "M6-B-OLF1500-St-co-acrylate backbone" copolymer prepared according to the protocol described in 1.2.5.2 in a mixture of 2.5 ml of THF:DMF=2:1 (volume ratio) was added to the reaction mixture. The reaction mixture was then kept at 40° C. for 40 hours.

[0823] After 40 hours of reaction, 15 mg (0.24 mmol) of ethanethiol are added to the reaction medium, which is kept stirring at ambient temperature for 4 hours.

[0824] The comb copolymer (PBB3) comprising the olefin macromonomer M6-B-OLF1500-St and poly(borate) polymer side chains was subsequently isolated by precipitation from acetone cooled using an ice bath, separated by settling the supernatant and dried in vacuo at 50°C overnight.

[0825] ο 1.3: Synthesis of comparative copolymers - Methods

[0826] 1.3.1 Random Linear Poly(Borate) Copolymer (LPB-Comparative):

[0827] The copolymer contains 6.0 mol% BC 12 E repeating unit (10 wt%). The average side chain length is 12 carbon atoms. Its number average molar mass is 45700 g / mol. Its dispersity is 1.39. Its number average degree of polymerization (DP n ) was 175. The number average molar mass and the dispersity were obtained by size exclusion chromatography using poly(methyl methacrylate) calibration and THF as eluent. The copolymer was obtained according to the protocol described in part 2 of the experimental part of application WO2016 / 113229.

[0828] 1.4 Synthesis of diol copolymers - method

[0829] 1.4.1 Linear polyglycol (LP diol):

[0830] The linear polyglycols were synthesized according to the protocol described in application FR1661400 or WO2018096252A1 (experimental part §1.2.).

[0831] The copolymer contains 7.0 mol % of monomers with diol functional groups (6.0 wt %). The average side chain length is 10.3 carbon atoms. Its number average molar mass is 40000 g / mol. Its dispersity is 1.46. Its number average degree of polymerization (DP n ) is 170.

[0832] 1.4.2 Synthesis of butyl methacrylate, methacrylate with diol functional group and olefin macromonomer Comb copolymer of OLF1500-St (CP diol)

[0833]

[0834] Scheme 16

[0835] The synthesis of comb copolymers bearing diol functionality in the backbone CP diol was performed according to the following scheme (Scheme 16 above).

[0836] 2.50 g (17.5 mmol) of butyl methacrylate (BMA), 0.18 g (0.89 mmol) of a methacrylate monomer with a diol function, 0.89 g (0.93 mmol) of the olefin macromonomer M6-B-OLF1500-St obtained according to the protocol described in section 1.1.4, 9.3 mg (0.04 mmol) of the RAFT transfer agent 2-cyano-2-propylbenzodithioate (PPBD), 2.8 mg (0.02 mmol) of azobisisobutyronitrile (AIBN) and 3.6 ml of anisole are introduced into a 25 ml Schlenk tube. The reaction medium is stirred and degassed by bubbling nitrogen for 30 minutes and then brought to 65° C. for 19 hours.

[0837] After 19 hours of polymerization, the Schlenk tube was placed in an ice bath to stop the polymerization. The polymer was then isolated by two consecutive precipitations from ice-cooled methanol, filtered and dried overnight at 50° C. under vacuum. The number average molar mass (M) of the copolymer thus obtained was n ) is 65500 g / mol, and the dispersion The number average degree of polymerization (DP n ) is 350. The first two values ​​were obtained by size exclusion chromatography using THF as eluent and poly(methyl methacrylate) calibration, while DP n pass 1 The conversion of monomers during the polymerization process was monitored by H NMR.

[0838] A poly(butyl methacrylate-co-alkyl methacrylate-co-OLF1500 OCP) copolymer CP diol containing 4.5 mol% of diol repeating units (4.6 wt%) and 6.8 mol% of OLF1500-OCP side chains (32 wt%) was obtained. The average length of the side chains was 10.9 carbon atoms.

[0839] 2. Preparation of the composition

[0840] Each polymer was dissolved in a Group III base oil to obtain a 10 wt% polymer solution. Once the polymer was completely dissolved in the oil, these solutions were used as stock solutions to prepare formulations for rheological studies.

[0841] ο 2.1 Ingredients for preparing the composition

[0842] Lubricating base oil

[0843] The lubricating base oil used in the compositions to be tested is an oil of group III of the API classification, sold by SK under the trade name Yubase 4. It has the following characteristics:

[0844] - Kinematic viscosity at 40°C measured according to standard ASTM D445 is 19.57 cSt;

[0845] - Kinematic viscosity at 100°C measured according to standard ASTM D445 is 4.23 cSt;

[0846] - Viscosity index measured according to standard ASTM D2270 is 122;

[0847] - Noack volatility measured according to standard DIN 51581 is 15% by weight;

[0848] - a flash point of 230° C. (degrees Celsius) measured according to standard ASTM D92;

[0849] - The pour point measured according to standard ASTM D97 is -15°C (degrees Celsius).

[0850] - Composition A (comparative) was obtained by the following method:

[0851] 0.53 g of a 39.2 wt % solution of LPB in a Group III base oil was mixed with 6.76 g of the same base oil. The mixture was stirred in a vortex mixer at ambient temperature for 1 minute. The LPB solution thus obtained was subsequently mixed with 0.71 g of a 25.4 wt % solution of LP diol in a Group III base oil. The mixture thus obtained was stirred in a vortex mixer at ambient temperature for 2 minutes. A solution containing 2.60 wt % of the linear copolymer LPB and 2.25 wt % of the linear copolymer LP diol was obtained.

[0852] - Composition B (according to the invention) is obtained by the following process:

[0853] 0.60 g of a comb-type poly(borate) copolymer PBB2 and 5.40 g of a group III base oil are introduced into a flask. The mixture thus obtained is kept stirred at 100° C. until the polyborate PBB2 is completely dissolved. A 10% by weight solution of the comb-type polyborate PBB2 is thus obtained.

[0854] 0.60 g of comb-type polyglycol copolymer CP diol and 5.40 g of group III base oil were introduced into a flask. The mixture thus obtained was kept stirring at 100° C. until the comb-type polyglycol copolymer CP diol was completely dissolved. A 10% by weight solution of brush-type polyglycol copolymer CP diol was thus obtained.

[0855] The poly (boric acid ester) PBB2 of 1.47g is mixed with the same base oil of 2.94g in 10 % by weight of solution in Group III base oil.The mixture is stirred at ambient temperature for 1 minute in a vortex mixer.Then the solution of the PBB2 thus obtained is mixed with the polyglycol CP diol of 1.47g in 10 % by weight of solution in Group III base oil, and kept stirring for 2 minutes at ambient temperature in a vortex mixer.Composition B is thus obtained, which comprises 2.50 % by weight of comb-type poly (boric acid ester) copolymer PBB2 and 2.50 % by weight of comb-type polyglycol copolymer CP diol.

[0856] - Composition C (according to the invention) is obtained by the following process:

[0857] 1.47 g of the 10 wt % solution of comb-type poly(boric acid ester) PBB2 prepared above was mixed with 3.83 g of a Group III base oil. The mixture was stirred in a vortex mixer at ambient temperature for 1 minute. The solution of PBB2 thus obtained was then mixed with 0.58 g of a 25.4 wt % solution of LP diol in a Group III base oil and kept stirring in a vortex mixer at ambient temperature for 2 minutes. A solution containing 2.50 wt % of comb-type poly(boric acid ester) copolymer PBB2 and 2.50 wt % of linear polyglycol copolymer LP diol was thus obtained.

[0858] - Composition D (according to the invention) is obtained by the following process:

[0859] 3.82 g of a 10 wt% solution of poly(borate) PBB2 in a group III base oil were mixed with 2.06 g of the same base oil. The mixture was stirred in a vortex mixer at ambient temperature for 1 minute. Comb-type poly(borate) copolymer PBB2 containing 6.50 wt% of composition D was thus obtained.

[0860] 3. Rheological properties of polymer solutions

[0861] Rheological studies were performed using a stress-controlled Couette MCR 501 rheometer from Anton Paar.

[0862] Rheological measurements were performed using a cylindrical geometry of the DG 26.7 reference. The viscosity was measured as a function of shear rate in the temperature range from 10°C to 150°C. For each temperature, the viscosity of the system was measured as a function of shear rate (from 1s -1 Up to 100s -1 ). The viscosity was measured at T = 10°C, 40°C, 70°C, 100°C, 130°C and 150°C (10°C to 150°C). Then, the measurement point (15s -1 Up to 100s -1)Calculate the average viscosity at each temperature.

[0863] Select the relative viscosity calculated according to the following formula,

[0864]

[0865] The change in system viscosity with temperature is expressed as A / C / C, since this quantity directly reflects the compensation for the natural viscosity loss of the Group III base oil of the polymer system under investigation. Table 1 below shows the change in absolute viscosity of compositions A to C with temperature.

[0866] 3.2 Rheological results

[0867] The relative viscosity of compositions B and C was studied over the temperature range of 10°C to 150°C and compared with the relative viscosity of composition A. -1 Up to 100s -1 The viscosity of the solution is calculated by taking the average of the absolute viscosities obtained at the shear rate of Fig. 9 shown.

[0868] Table 1

[0869]

[0870] When linear polydiol LP diol and linear polyborate LPB are present together in the same lubricating composition (Composition A), it is observed that the natural viscosity loss of the Group III base oil is significantly compensated over the entire temperature range studied. This is reflected in a practically linear increase in relative viscosity from 10°C to 150°C ( Fig.11 , dotted line-open square). However, composition A also affects the cold viscosity of the formulation, with a relative viscosity of 1.58 at 10°C.

[0871] In the same lubricating composition (composition B), the presence of comb-type polyglycol copolymer CP diol and comb-type poly(borate) copolymer PBB2 can significantly reduce the relative viscosity at low temperature, as low as η at 10°C. 相对 =1.30. At the same time, with preparation A ( Fig. 9 , dashed / solid asterisks), the formulation has a lower compensation for the natural viscosity loss of Group III base oil at high temperature.

[0872] Composition B was diluted to 2.10 wt% of the comb-type polyglycol copolymer CP diol and 2.10 wt% of the comb-type poly(borate) copolymer PBB2, so that the relative viscosity could be further reduced to η at 10°C. 相对 =1.21( Fig.10-Bd, dashed asterisk). However, unlike the composition comprising the linear copolymer, composition Bd can be used at high temperatures (η at 150°C) even though it has a relatively low relative viscosity under cold conditions. 相对 =1.43) maintains its viscosity increasing performance. Relative viscosity values ​​for three consecutive heating and cooling cycles (Bd-1, Bd-2 and Bd-3) from 10°C to 150°C are shown. These changes are negligible during the 3 cycles, and the relative viscosity always increases from 10°C to 150°C ( Fig.11 ).

[0873] When the comb-type poly(borate) copolymer PBB2 and the linear polydiol LP diol are present simultaneously in the same lubricating composition (composition C), the advantages of both systems are combined. In the case of this combination of associative copolymer structure types, a significant compensation of the natural viscosity loss of the base oil is observed in the temperature range of 100°C to 150°C compared to formulations containing only linear copolymers ( Fig. 9 , continuous solid squares), which occurs in conjunction with a significant decrease in relative viscosity at low temperatures (from 1.58 to 1.36 at 10 °C).

[0874] Relative viscosity values ​​for three consecutive heating and cooling cycles (C-1, C-2 and C-3) from 10°C to 150°C are shown. These changes over the 3 cycles are small and consistently increase the relative viscosity by about 0.4 from 10°C to 150°C, reflecting good compensation for the natural viscosity loss of Group III base oils in this temperature range ( Fig.12 ).

[0875] The poly(borate) comb copolymer PBB2 alone at a concentration of 6.50 wt% in the Group III base oil (Composition D) does not compensate for the loss of natural viscosity of the Group III base oil as much as Formulations B and C ( Fig.13 and Fig. 9 ), however, it can change the relative viscosity from 1.4 at 10°C to 1.50 at 150°C.

Claims

1. A comb copolymer A2 comprising at least two borate functional groups, the copolymer comprising a main chain and side chains, at least a portion of the side chains of the copolymer A2 being composed of oligomers comprising more than 50 carbon atoms and comprising polyolefin segments. 2 . The comb-type copolymer A2 according to claim 1 , wherein at least a part of the side chains of the copolymer A2 is composed of an oligomer having a degree of polymerization of 5 to 1000. 3 . 3 . The comb copolymer A2 according to claim 1 , wherein the side chains consisting of oligomers containing more than 30 carbon atoms amount to 3% to 95% by weight, relative to the total weight of the copolymer A2. 4 . The comb copolymer A2 according to claim 1 , wherein the side chains comprising polyolefin segments are 3% to 85% by weight, relative to the total weight of the copolymer A2.

5. The comb copolymer A2 according to claim 1, wherein the oligomer O1 is present in the copolymer A2 in the form of repeating units corresponding to one or more than one monomer M6 of the general formula (IX): in: Q1 is selected from -H, -CH3 and -CH2-CH3; Q2 is selected from the group consisting of -Q', -O-Q', -C(O)-O-Q', -OC(O)-Q', -S-(CH2)2-C(O)-O-Q', -S-Q', -N(H)-C(O)-Q' and -C(O)-N(H)-Q', wherein Q' is a polyolefin, n represents an integer from 0 to 1, A represents a group selected from -A1-, -O-(-A2-O-) n' -A1-, -C(O)-O-(-A2-O-) n' -A1-、-OC(O)-(-A2-O-) n' -A1-、-S-(-A2-O-) n' -A1-, -N(H)-C(O)-(-A2-O-) n' -A1- and -C(O)-N(H)-(-A2-O-) n' -A1- divalent group, wherein A1 is selected from C1 to C 30 Alkyl, C6 to C 30 Aryl or C6 to C 30 A divalent aralkyl group, A2 is a divalent group selected from C2 to C4 alkyl groups, n' is an integer, and n' represents 0 or 1.

6. The comb copolymer A2 according to claim 1, comprising at least repeating units of the monomer M4 corresponding to the formula (IV): in: -t is an integer equal to 0 or 1; -u is an integer equal to 0 or 1; -M and R8 are divalent linking groups, which are the same or different and are selected from C6 to C 18 Aryl, C7 to C 24 Arylalkyl and C2 to C 24 alkyl; -X is a functional group selected from -OC(O)-, -C(O)-O-, -C(O)-N(H)-, -N(H)-C(O)-, -S-, -N(H)-, -N(R'4)-, and -O-, wherein R'4 is a hydrocarbon chain containing 1 to 15 carbon atoms; -R9 is selected from -H, -CH3 and -CH2-CH3; -R 10 and R 11 identical or different, representing a group chosen from a hydrogen atom or a hydrocarbon radical containing 1 to 30 carbon atoms, which is optionally substituted by one or more than one group chosen from: a hydroxyl group or an -OJ or -C(O)-OJ group, in which J is a hydrocarbon radical containing 1 to 24 carbon atoms.

7. The comb copolymer A2 according to claim 1, comprising at least repeating units of a monomer M5 corresponding to the general formula (V): in: -R 12 is selected from -H, -CH3 and -CH2-CH3, -R 13 Selected from C6 to C 18 Aryl and R' 13 、-C(O)-OR' 13 、-OR' 13 、-SR' 13 and -C(O)-N(H)-R' 13 C6 to C 18 Aryl, where R' 13 C1 to C 30 alkyl.

8. The comb copolymer A2 according to claim 1, comprising repeating units corresponding to at least one monomer M3 of the general formula (X): in: - Z1, Z2 and Z3 are the same or different and represent a group selected from hydrogen atoms, C1 to C 12 alkyl or -OZ' or -C(O)-O-Z' group, wherein Z' is C1 to C 12 alkyl.

9. The comb copolymer A2 according to claim 8, wherein the monomer M3 is styrene.

10. The comb-type copolymer A2 according to claim 8, wherein the repeating unit corresponding to the monomer of formula (X) accounts for 2 mol% to 50 mol% relative to the total moles of the monomers constituting the copolymer A2.

11. A composition obtained by mixing at least the following substances: - polyglycol compound A1, - The copolymer A2 according to claim 1.

12. The composition according to claim 11, wherein the polyglycol compound A1 is a copolymer obtained by copolymerizing the following substances: ■ At least one first monomer M1 having the general formula (I): in: -R1 is selected from -H, -CH3 and -CH2-CH3; -y is an integer equal to 0 or 1; -Y represents a group consisting of C1 to C 20 a divalent linking group of an alkyl chain, which optionally comprises one or more than one ether-O-bridge; - X1 and X2 are the same or different and are selected from hydrogen, tetrahydropyranyl, methoxymethyl, tert-butyl, benzyl, trimethylsilyl and tert-butyldimethylsilyl; or -X1 and X2 form a bridge of the following formula with the oxygen atom: in: - The asterisk (*) indicates a bond to an oxygen atom, - R'2 and R"2 are the same or different and are selected from hydrogen and C1 to C 11 alkyl; or -X1 and X2 form a boric acid ester with the oxygen atom: in: - The asterisk (*) indicates a bond to an oxygen atom, -R"'2 is selected from C6 to C 30 Aryl, C7 to C 30 Arylalkyl and C2 to C 30 alkyl; ■ At least one second monomer M2 having the general formula (II): in: -R2 is selected from -H, -CH3 and -CH2-CH3; -R3 is selected from: -C(O)-O-R'3; -O-R'3; -S-R'3 and -C(O)-N(H)-R'3, wherein R'3 is C1 to C 30 alkyl.

13. A lubricating composition, which is obtained by mixing at least the following substances: - Lubricating oil; and - A composition according to claim 11.

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