Process for synthesizing a block polymer comprising a poly(1,3-cyclohexadiene) block and a random copolymer block based on ethylene and on a 1,3-diene

Abstract

The invention relates to a process for synthesizing a block polymer of formula A-B-(C)n wherein the symbol A represents a poly(1,3-cyclohexadiene) block, the symbol B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mol% of ethylene units, and the symbol C represents a polyethylene block, n being equal to 0 or 1, the 1,3-diene being an α-olefin. The invention also relates to a block polymer of formula A-B or A-B-C which can be obtained by means of the process of the invention, wherein the symbol A represents a poly(1,3-cyclohexadiene) block with a glass transition temperature of greater than 120°C, the symbol B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mol% of ethylene units, and the symbol C represents a polyethylene block, the 1,3-diene being an α-olefin.

Description

[0001] Synthesis process for a block polymer comprising a poly(1,3-cyclohexadiene) block and a random copolymer block based on ethylene and a 1,3-diene.

[0002] The field of the invention is that of processes for the synthesis of block polymers which comprise at least one thermoplastic block having a glass transition temperature much greater than 100°C and linked to a copolymer block which is rich in ethylene and which contains units of a 1,3-diene, the 1,3-diene being an α-olefin.

[0003] It has been shown, for example in patent applications WO 2014114607 Al, WO 2016012259 Al, and WO 2016087248 Al, that ethylene-rich copolymers containing units of an α-olefin that is a 1,3-diene exhibit interesting properties of stiffness, hysteresis, wear, and adhesion. To improve their properties, it has been proposed to modify these copolymers by introducing one or more rigid blocks. For example, the introduction of a polystyrene block to prepare a dibloc is described in patent application WO 2019077235 according to a three-step process, the first step being the synthesis of a living polystyrene, polystyryllithium, by anionic polymerization of styrene, the second step being the reaction of the living polystyrene with a neodymocene borohydride, the third step being the subsequent polymerization of 1,3-diene and ethylene.The introduction of a polystyrene block and an ethylene block at the ends of the copolymer to prepare a triblock is also described in patent application WO 2024056662 by the synthesis of a living polystyrene by anionic polymerization of styrene, its reaction with an organomagnesium, followed by the statistical polymerization of 1,3-diene and ethylene in the presence of a neodymocene borohydride, and then the homopolymerization of ethylene.

[0004] Since the glass transition temperature of polystyrene does not exceed 100°C, these block polymers containing a polystyrene block tend to flow above 100°C. This flow phenomenon consequently affects the mechanical properties of these block polymers at these temperatures. Therefore, there is a need to find a synthesis process that leads to the production of block polymers containing an ethylene-rich diene block and exhibiting improved thermal stability. To provide such thermally stable block polymers, it is also important to find a process that allows for the preparation of these block polymers with precise control over the macrostructure of each block while maintaining high production rates.

[0005] The inventors have discovered a new process that solves the problems mentioned.

[0006] The invention relates to a process for synthesizing a block polymer of formula AB-(C)n in which the symbol A represents a poly(1,3-cyclohexadiene) block, the symbol B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C represents a polyethylene block, n being equal to 0 or 1, the 1,3-diene being an α-olefin, which process comprises: the sequence of steps a), b), c) and d) when n is equal to 0,

[0007] 2024PAT00122WO the sequence of steps a), b), c) and d) followed by step e) when n is equal to 1,

[0008] - step a) being the reaction in a hydrocarbon solvent of an organolithium compound and a multidentate polar agent in a ratio between the number of moles of the multidentate polar agent and the number of moles of the organolithium compound greater than 0.5 and less than 1 to form a complex consisting of a multidentate polar agent and an organolithium compound,

[0009] - step b) being the anionic polymerization of 1,3-cyclohexadiene initiated by the complex consisting of a multidentate polar agent and an organolithium compound in a hydrocarbon solvent, to form a poly(1,3-cyclohexadienyl)lithium,

[0010] - step c) being the reaction between poly(l,3-cyclohexadienyl)lithium and a halide of an organomagnesium compound of formula (I) to form an organomagnesium compound of formula R-Mg-A,

[0011] R-Mg-X (I)

[0012] R comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by a methyl, an ethyl or an isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by a methyl, an ethyl or an isopropyl, the magnesium atom being in ortho position with respect to each of said two carbon atoms,

[0013] where X is a halogen atom, and A represents a poly(1,3-cyclohexadiene) polymer chain,

[0014] - step d) being the statistical polymerization of a monomer mixture containing ethylene and 1,3-diene, in the presence of a catalytic system comprising a metallocene of formula (II) and the organomagnesium compound of formula R-Mg-A, P(Cp 1 CP 2 )Nd(BH4)(i +y) .L y -N x (II)

[0015] CP 1 and Cp 2, identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,

[0016] P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom,

[0017] L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium,

[0018] N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0,

[0019] - step e) being the subsequent homopolymerization of ethylene.

[0020] The invention also relates to a block polymer of formula AB or ABC, the symbol A representing a poly(1,3-cyclohexadiene) block with a glass transition temperature above 120°C, preferably above 140°C, the symbol B representing a statistical copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C representing a polyethylene block, the 1,3-diene being an α-olefin, which block polymer is capable of being obtained by the process according to the invention.

[0021] Detailed description:

[0022] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​greater than "a" and less than "b" (that is, excluding bounds a and b), while any

[0023] 2024PAT00122WO range of values ​​designated by the expression "from a to b" means the range of values ​​from "a" to "b" (i.e. including the strict bounds a and b).

[0024] Unless otherwise stated, the rates of units resulting from the insertion of a monomer into a polymer are expressed as a mole percentage relative to the total number of monomer units that constitute the polymer.

[0025] The compounds mentioned in the description can be of fossil origin or bio-based. In the latter case, they may be partially or entirely derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of previously used materials; that is, they may be partially or entirely produced through a recycling process, or obtained from raw materials themselves derived from a recycling process.

[0026] Step a) consists of preparing a complex of a multidentate polar agent and an organolithium compound by reacting the organolithium compound and the multidentate polar agent in a hydrocarbon solvent. In the complex of a multidentate polar agent and an organolithium compound, the lithium ion is chelated by the multidentate polar agent. For example, it is well known that multidentate polar agents have the property of chelating the lithium ion from organolithium compounds, thereby enhancing the nucleophilicity of the organolithium compounds.

[0027] Organolithium compounds are commonly defined as compounds consisting of a carbon chain, preferably hydrocarbon, with a carbon-lithium bond. Organolithium compounds are preferentially alkyllithium compounds, with the alkyl group of the alkyllithium being either linear or branched. The alkyl group of the alkyllithium may contain one or more carbon atoms, i.e., at least two carbon atoms. Organolithium compounds are more preferentially butyllithium compounds, and even more preferentially n-butyllithium compounds. Multidentate polarizing agents are preferentially bidentate polarizing agents such as N,N,N',N'-tetramethylenediamine, 1,2-dipiperidinoethane, 1,4-diazabicyclo[2,2,2]octane (DABCO), and more preferably N,N,N',N'-tetramethylenediamine.

[0028] In step a) according to the invention, the ratio between the number of moles of the multidendate polarizing agent and the number of moles of the organolithium compound is greater than 0.5 and less than 1. Using a ratio greater than or equal to 1 results in a significant decrease in the catalytic activity of the polymerization reaction in step d), leading to the formation of block, diblock, and triblock polymers without control over the macrostructure of the blocks. This also reduces the process productivity in the synthesis of block polymers. Similarly, a ratio less than or equal to 0.5 leads to the formation of block, diblock, and triblock polymers, again without control over the macrostructure.Using a ratio both greater than 0.5 and less than 1 avoids these drawbacks while ensuring the synthesis of block, diblock, and triblock polymers, in which the block represented by the symbol A has a glass transition temperature well above 100°C. The hydrocarbon solvent in step a) is preferably an aliphatic solvent, more preferably cyclohexane, methylcyclohexane, or a mixture thereof.

[0029] 2024PAT00122WO Step b) consists of preparing a poly(1,3-cyclohexadienyl)lithium by anionic polymerization of 1,3-cyclohexadiene in a hydrocarbon solvent in the presence of the complex consisting of the polar agent and the organolithium compound which was prepared in step a). The complex consisting of the polar agent and the organolithium compound acts as a initiator in the polymerization of 1,3-cyclohexadiene.

[0030] Poly(l,3-cyclohexadienyl)lithium is known to be a homopolymer of 1,3-cyclohexadiene whose polymer chains possess a reactive center with respect to polymerization, in this case a carbon-lithium bond, particularly at the end of the polymer chain.

[0031] The hydrocarbon solvent in step b) is preferably an aliphatic solvent, more preferably cyclohexane, methylcyclohexane, or a mixture thereof. Advantageously, the hydrocarbon solvent in step b) is the same as that used in step a).

[0032] The ratio of hydrocarbon solvent to 1,3-cyclohexadiene required for the formation of poly(1,3-cyclohexadienyl)lithium is determined by a person skilled in the art based on the desired viscosity of the poly(1,3-cyclohexadienyl) polymer solution. This viscosity depends not only on the concentration of the polymer solution but also on numerous other factors, such as the length of the poly(1,3-cyclohexadienyl) chains, the intermolecular interactions between the poly(1,3-cyclohexadienyl)lithium chains, and the temperature of the polymer solution. Therefore, a person skilled in the art adjusts the amount of solvent on a case-by-case basis.

[0033] The polymerization temperature for forming poly(l,3-cyclohexadienyl)lithium can vary widely. Generally, it is above -20°C and below 80°C. Preferably, it is above 0°C and below 60°C.

[0034] Step b) allows the preparation of a block with a glass transition temperature much higher than 100°C with good control of the macrostructure of the block.

[0035] Step c) consists of reacting poly(l,3-cyclohexadienyl)lithium with a halide of an organomagnesium compound of formula R-Mg-X to form an organomagnesium compound of formula R-Mg-A, R comprising a benzene ring with two substituted carbon atoms, one of the two being substituted by a methyl, an ethyl or an isopropyl or forming a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by a methyl, an ethyl or an isopropyl, the magnesium atom being in ortho position with respect to each of said two carbon atoms, X being a halogen atom, A representing a poly(l,3-cyclohexadiene) polymer chain.

[0036] The halide of an organomagnesium compound of formula R-Mg-X is preferably of formula (la) in which Ri and Rs, identical or different, represent a methyl or an ethyl, R2, R3 and R4, identical or different, being a hydrogen atom or an alkyl, X being a halogen atom.

[0037] 2024PAT00122WO

[0038] X preferably represents a chlorine atom or a bromine atom, more preferably a bromine atom. Preferably, Ri and Rs each represent a methyl group. Preferably, R2 and R4 each represent a hydrogen atom. Advantageously, Ri and R5 each represent a methyl group, and R2 and R4 each represent a hydrogen atom. Even more advantageously, X represents a bromine atom, Ri and R5 each represent a methyl group, and R2 and R4 each represent a hydrogen atom. In step c), the reaction between poly(1,3-cyclohexadienyl)lithium and the halide of an organomagnesium can be carried out by adding the polymer solution obtained at the end of step b) to a solution of the halide of an organomagnesium R-Mg-X, but it is carried out preferentially by adding a solution of the halide of an organomagnesium R-Mg-X to the polymer solution obtained at the end of step b).The solution of the organomagnesium compound R-Mg-X halide is generally a solution in an ether, preferably diethyl ether or dibutyl ether. The concentration of poly(1,3-cyclohexadienyl)lithium is preferably 0.001 to 1 mol lithium equivalent / L, more preferably 0.01 to 0.2 mol lithium equivalent / L, while that of the organomagnesium compound R-Mg-X is preferably 1 to 5 mol / L, more preferably 2 to 3 mol / L. The reaction between poly(1,3-cyclohexadienyl)lithium and the organomagnesium compound R-Mg-X halide is typically carried out at a temperature ranging from 0°C to 60°C. Contact is preferably made at a temperature between 0°C and 23°C. As with any synthesis carried out in the presence of organometallic compounds, the contact and reaction take place under anhydrous conditions in an inert atmosphere. Typically, solvents and solutions are used under anhydrous nitrogen or argon.The various stages of the process are generally carried out under agitation.

[0039] Once formed and without being separated from the reaction medium of step c), organomagnesium T of formula R-Mg-A can be stored in airtight containers, for example capped bottles, at a temperature between -25°C and 23°C, under an inert and anhydrous atmosphere, before it is used in step d).

[0040] Step d) consists of forming a statistical copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units. The 1,3-diene whose monomeric units constitute the statistical copolymer block is an α-olefin. As is known, an α-olefin is an olefin with a terminal double bond and is therefore distinct from 1,3-cyclohexadiene. A polymer comprising units of a 1,3-diene is defined as a polymer that contains units of one 1,3-diene or units of several 1,3-dienes, that is, at least two 1,3-dienes.

[0041] 2024PAT00122WO Step d) is the statistical polymerization of a monomer mixture containing ethylene and said 1,3-diene in the presence of a catalytic system (or catalytic composition) comprising a metallocene and the reaction product of step c), in this case the organomagnesium compound of formula R-Mg-A. The organomagnesium compound of formula R-Mg-A obtained in step c) is used as a co-catalyst of the catalytic system in step d). It is generally used in step d) without being separated from the reaction medium of step c).

[0042] The metallocene used in the catalytic system has the formula (II) P(Cp 1 CP 2 )Nd(BH4)(i+ y) -L y -Nx (II)

[0043] CP 1 and Cp 2 , identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,

[0044] P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom,

[0045] L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium,

[0046] N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0.

[0047] In formula (II), the neodymium atom is linked to a ligand molecule consisting of the two Cp groups 1 and Cp 2 connected to each other by bridge P. Preferably, the symbol P, designated as bridge, corresponds to the formula ZR X R 2 , Z representing a silicon or carbon atom, R 1 and R 2 , identical or different, representing an alkyl group comprising 1 to 20 carbon atoms, preferably methyl. More preferably, the P bridge has the formula SiRx R 2 , R 1 and R 2 , being identical and as defined previously. Even more preferably, P satisfies the formula SiMe?.

[0048] Examples of substituted cyclopentadienyl and fluorenyl groups include those substituted with alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 12 carbon atoms, or trialkylsilyl groups such as SiMes. The choice among alkyl, aryl, and trialkylsilyl groups is also influenced by the availability of the corresponding molecules, namely the substituted cyclopentadienes and fluorenes, because these are either commercially available or easily synthesized.

[0049] Examples of substituted cyclopentadienyl groups include those substituted at both position 2 (or 5) and position 3 (or 4), particularly those substituted at position 2, more specifically the tetramethylcyclopentadienyl group. In the present application, in the case of the cyclopentadienyl group, position 2 (or 5) refers to the position of the carbon atom adjacent to the carbon atom to which the P-bridge is attached, as is

[0050] 2024PAT00122WO represented in the diagram below.

[0051] Examples of substituted fluorenyl groups include those substituted at positions 2,7, 3, or 6, particularly the 2,7-ditertiobutyl-fluorenyl and 3,6-ditertiobutyl-fluorenyl groups. Positions 2, 3, 6, and 7 respectively designate the positions of the carbon atoms in the rings, as shown in the diagram below, with position 9 corresponding to the carbon atom to which the P-bridge is attached.

[0052] Preferably, Cp 1 and Cp 2 are chosen from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula CBHS. More preferably, Cp 1 and Cp 2 are identical and are chosen from the group consisting of substituted fluorenyl groups and the fluorenyl group. Advantageously, in formula (I) Cp 1 and Cp 2 Each represents a substituted fluorenyl group or a fluorenyl group, preferably a fluorenyl group. The fluorenyl group has the formula CBHS.

[0053] Preferably, the metallocene has the formula (II-1), (II-2), (II-3), (II-4) or (II-5): [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] (II-1) [{Me2SiFlu2Nd(p-BH4)2Li(THF)}2] (II-2) [Me2SiFlu2Nd(p-BH4)(THF)] (II-3) [{Me2SiFlu2Nd(p-BH4)(THF)}2] (II-4) [Me2SiFlu2Nd(p-BH4)] (II-5) the symbol Flu representing the C13FL group.

[0054] The metallocene used to prepare the catalytic system can be in the form of crystalline or non-crystalline powder, or as single crystals. The metallocene can be monomeric or dimeric, depending on the method of preparation, as described in the patent application.

[0055] WO 2007054224. Metallocene can be prepared conventionally by a process analogous to that described in patent application WO 2007054224, in particular by reacting the salt of an alkali metal of the ligand with a rare-earth borohydride under inert and anhydrous conditions in a suitable solvent, such as an ether, like diethyl ether or tetrahydrofuran, or any other solvent known to those skilled in the art. After reaction, the metallocene is separated from the reaction byproducts by techniques known to those skilled in the art.

[0056] 2024PAT00122WO of the art, such as filtration or precipitation in a second solvent. The metallocene is ultimately dried and isolated in solid form.

[0057] Like all syntheses carried out in the presence of organometallic compounds, the synthesis of metallocene takes place under anhydrous conditions in an inert atmosphere. Typically, the reactions are conducted using solvents and anhydrous compounds under anhydrous nitrogen or argon.

[0058] The catalytic system can be prepared conventionally by a process analogous to that described in patent applications WO 2007054224 or WO 2007054223. For example, the co-catalyst and the metallocene are reacted in a hydrocarbon solvent, typically at a temperature of 20 to 80°C for a duration of 5 to 60 minutes. The amounts of co-catalyst and metallocene reacted are such that the ratio of the number of moles of Mg in the co-catalyst to the number of moles of rare-earth metal in the metallocene is preferably from 1 to 100, and more preferably from 1 to less than 10. The range of values ​​from 1 to less than 10 is particularly favorable for obtaining polymers with high molar masses. The catalytic system is generally prepared in a hydrocarbon solvent, either aliphatic such as methylcyclohexane or aromatic such as toluene.Generally, after its synthesis, the catalytic system is used as is in the polymer synthesis process according to the invention.

[0059] The catalytic system is generally in the form of a solution in a hydrocarbon solvent. The hydrocarbon solvent can be aliphatic, such as methylcyclohexane, or aromatic, such as toluene. The hydrocarbon solvent is preferably aliphatic, and more specifically, methylcyclohexane. Generally, the catalytic system is stored as a solution in the hydrocarbon solvent before being used in polymerization. This can then be referred to as a catalytic solution, which comprises the catalytic system and the hydrocarbon solvent. The concentration of the catalytic solution is typically defined by the metallocene content in the solution. The metallocene concentration is preferably from 0.0001 to 0.2 mol / L, and more preferably from 0.001 to 0.03 mol / L.

[0060] As with any synthesis carried out in the presence of organometallic compounds, the synthesis of the catalytic system takes place under anhydrous conditions in an inert atmosphere. Typically, the reactions are conducted using solvents and anhydrous compounds under anhydrous nitrogen or argon.

[0061] The catalytic system is typically introduced into the reactor containing the polymerization solvent and the monomer mixture containing ethylene and 1,3-diene. To achieve the desired macrostructure of the statistical copolymer block, those skilled in the art adjust the polymerization conditions, particularly the molar ratio of magnesium in the cocatalyst to the Nd metal constituting the metallocene. The molar ratio can reach 100, although a molar ratio below 10 is more favorable for obtaining polymers with high molar masses.

[0062] 2024PAT00122WO In step d), the monomer mixture containing ethylene and 1,3-diene generally contains more than 50 mol% ethylene and is preferably a mixture of ethylene and 1,3-diene, in which case the block represented by the symbol B is a statistical copolymer of ethylene and 1,3-diene, that is, a block whose constituent monomer units are those resulting from the statistical copolymerization of ethylene and 1,3-diene. The 1,3-diene is preferably 1,3-butadiene or isoprene, or a mixture of 1,3-dienes, one of which is 1,3-butadiene. The 1,3-diene is more preferably 1,3-butadiene.

[0063] According to a particular embodiment of the invention, the monomer mixture containing ethylene and 1,3-diene contains less than 90 mole percent of ethylene, preferably at most 85 mole percent of ethylene. This embodiment is particularly advantageous for obtaining a soft block B, that is to say, one having elastomeric properties.

[0064] Preferably, a continuous addition of ethylene and 1,3-diene is carried out in the polymerization reactor, in which case the polymerization reactor is a fed reactor. This embodiment is particularly suitable for the statistical incorporation of ethylene and 1,3-diene.

[0065] The polymerization temperature generally varies from 30 to 160°C, preferably from 30 to 120°C. During the preparation of the statistical copolymer block, the temperature of the reaction medium is advantageously kept constant throughout the copolymerization process, and the total pressure in the reactor is also advantageously kept constant. The preparation of the statistical copolymer block is completed by stopping the monomer feed and then degassing the reactor to reduce the reactor pressure to approximately 0 to 0.5 bar (relative).

[0066] Step e) consists of preparing a polyethylene block following the preparation of the statistical copolymer block by the subsequent polymerization of ethylene. The subsequent polymerization of ethylene is carried out by applying ethylene pressure in the reactor, the ethylene pressure being maintained constant until the desired ethylene consumption is reached to achieve the desired number-average molar mass of the polyethylene block. The ethylene polymerization temperature is preferably maintained at the same temperature as that of the preparation of the statistical copolymer block. The polymerization temperature for preparing the polyethylene block generally varies in the range of 30 to 160°C, preferably from 30 to 120°C. The pressure for preparing the polyethylene block generally varies in the range of 1 bar to 150 bar, and preferably from 1 bar to 10 bar.The synthesis of the polyethylene block is complete when the polyethylene block reaches the desired number-average molar mass.

[0067] At the end of step d) in the case of the synthesis of a block polymer of formula AB-(C)n where n is equal to 0, or at the end of step e) in the case of the synthesis of a block polymer of formula AB-(C)n where n is equal to 1, the polymerization is stopped by deactivating the active polymerization sites, for example by cooling the polymerization medium or by adding an alcohol, preferably an alcohol containing 1 to 3 carbon atoms, for example ethanol. The block polymer can be recovered according to the

[0068] 2024PAT00122WO classic techniques known to those skilled in the art, such as precipitation, evaporation of the solvent under reduced pressure or steam stripping.

[0069] Advantageously, the sequence of steps a), b), c), d) and where applicable followed by step e) is carried out without separating the reaction products of each of the intermediate steps a), b), c) and where applicable d). The polymerizations of steps a), b), c), d) and e) can be carried out continuously or discontinuously.

[0070] The sequence of the constituent steps of the process according to the invention ensures both good control of the macrostructure of each of the blocks A, B and C and good catalytic activity in steps d) and e) which results in a productive process.

[0071] The process according to the invention thus allows the preparation of block polymers of formula AB or ABC, where A represents a poly(1,3-cyclohexadiene) block, B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mole percent ethylene units, and C represents a polyethylene block, the 1,3-diene being an α-olefin, advantageously 1,3-butadiene. In the block polymers that can be obtained by the process according to the invention and which are another object of the invention, the poly(1,3-cyclohexadiene) block has a glass transition temperature above 120°C, preferably above 140°C. Preferably, in the polymers according to the invention, C represents a polyethylene block with a melting temperature above 90°C, preferably above 100°C.

[0072] The block polymers according to the invention exhibit good thermal properties, since they comprise a rigid block having a glass transition temperature much higher than 100°C.

[0073] In summary, the invention is preferably implemented according to any one of the following embodiments 1 to 22:

[0074] Mode 1: A process for synthesizing a block polymer of formula AB-(C)n in which the symbol A represents a poly(1,3-cyclohexadiene) block, the symbol B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C represents a polyethylene block, n being equal to 0 or 1, the 1,3-diene being an α-olefin, which process comprises: the sequence of steps a), b), c) and d) when n is equal to 0, the sequence of steps a), b), c) and d) followed by step e) when n is equal to 1,

[0075] - step a) being the reaction in a hydrocarbon solvent of an organolithium compound and a multidentate polar agent in a ratio between the number of moles of the multidentate polar agent and the number of moles of the organolithium compound greater than 0.5 and less than 1 to form a complex consisting of a multidentate polar agent and an organolithium compound,

[0076] - step b) being the anionic polymerization of 1,3-cyclohexadiene initiated by the complex consisting of a multidentate polar agent and an organolithium compound, in a hydrocarbon solvent, to form a poly(1,3-cyclohexadienyl)lithium,

[0077] - step c) being the reaction between poly(1,3-cyclohexadienyl)lithium and a halide of an organomagnesium compound of formula (I) to form an organomagnesium compound of formula R-

[0078] 2024PAT00122WO Mg-A,

[0079] R-Mg-X (I)

[0080] R comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by a methyl, an ethyl or an isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by a methyl, an ethyl or an isopropyl, the magnesium atom being in ortho position with respect to each of said two carbon atoms,

[0081] where X is a halogen atom, and A represents a poly(1,3-cyclohexadiene) polymer chain,

[0082] - step d) being the statistical polymerization of a monomer mixture containing ethylene and 1,3-diene, in the presence of a catalytic system comprising a metallocene of formula (II) and the organomagnesium compound of formula R-Mg-A,

[0083] P(Cp 1 CP 2 )Nd(BH4)(i +y) .L y -N x (II)

[0084] CP 1 and Cp 2, identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,

[0085] P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom,

[0086] L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium,

[0087] N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0,

[0088] - step e) being the subsequent homopolymerization of ethylene.

[0089] Mode 2: Process according to mode 1 in which the organolithium compound is a butyllithium.

[0090] Mode 3: Process according to mode 1 or 2 in which the organolithium compound is n-butyllithium.

[0091] Mode 4: Process according to any one of modes 1 to 3 in which the multidentate polar agent is N,N,N',N'-tetramethylenediamine.

[0092] Mode 5: Process according to any one of modes 1 to 4 in which the hydrocarbon solvent in steps a) and b) is an aliphatic solvent.

[0093] Mode 6: A process according to any one of modes 1 to 5 in which the hydrocarbon solvent in steps a) and b) is cyclohexane, methylcyclohexane or a mixture thereof.

[0094] Mode 7: Process according to any one of modes 1 to 6 in which the halide of an organomagnesium compound has the formula (la)

[0095] 2024PAT00122WO

[0096] Ri and R5, identical or different, represent a methyl or an ethyl, R2, R3 and R4, identical or different, being a hydrogen atom or an alkyl, X being a halogen atom.

[0097] Mode 8: Process according to mode 7 in which Ri and R5 each represent a methyl and R2 and R4 each represent a hydrogen atom.

[0098] Mode 9: A process according to any one of modes 1 to 8 in which X represents a chlorine atom or a bromine atom, preferably a bromine atom.

[0099] Mode 10: A process according to any one of modes 1 to 9 in which the monomer mixture containing ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene.

[0100] Mode 11: Process according to any one of modes 1 to 10 in which the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes of which one is 1,3-butadiene.

[0101] Mode 12: A method according to any one of modes 1 to 11 in which Cp 1 and Cp 2 are chosen from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula CBHS.

[0102] Mode 13: A method according to any one of modes 1 to 12 in which Cp 1 and Cp 2 each represent an unsubstituted fluorenyl group with the formula CBHS.

[0103] Mode 14: A method according to any one of modes 1 to 13 in which the bridge P conforms to the formula ZR X R 2 , Z representing a silicon or carbon atom, R 1 and R 2 , identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, preferably a methyl.

[0104] Mode 15: Process according to any one of modes 1 to 14 in which the metallocene is of formula (II-1), (II-2), (II-3), (II-4) or (II-5): [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] (II-1) [{Me2SiFlu2Nd(p-BH4)2Li(THF)}2] (II-2) [Me2SiFlu2Nd(p-BH4)(THF)] (II-3) [{Me2SiFlu2Nd(p-BH4)(THF)}2] (II-4) [Me2SiFlu2Nd(p-BH4)] (II-5) the symbol Flu representing the CBHS group.

[0105] Mode 16: Process according to any one of modes 1 to 15 in which the poly(l,3-cyclohexadiene) block has a glass transition temperature greater than 120°C.

[0106] 2024PAT00122WO Mode 17: Process according to any one of modes 1 to 16 in which the poly(l,3-cyclohexadiene) block has a glass transition temperature greater than 140°C.

[0107] Mode 18: Block polymer of formula AB or ABC, the symbol A representing a poly(l,3-cyclohexadiene) block with a glass transition temperature above 120°C, the symbol B representing a statistical copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C representing a polyethylene block, the 1,3-diene being an α-olefin.

[0108] Mode 19: Block polymer according to mode 18 in which the symbol A represents a poly(l,3-cyclohexadiene) block with a glass transition temperature above 140°C.

[0109] Mode 20: Block polymer according to mode 18 or 19 in which the symbol C represents a polyethylene block with a melting temperature above 90°C.

[0110] Mode 21: Block polymer according to mode 18 or 19 in which the symbol C represents a polyethylene block with a melting temperature above 100°C.

[0111] Mode 22: Block polymer according to any one of modes 18 or 21 in which the 1,3-diene is 1,3-butadiene.

[0112] The aforementioned features of the present invention, as well as others, will be better understood upon reading the following description of several examples of embodiments of the invention, given by way of illustration.

[0113] Examples

[0114] The name EBR is used to designate a statistical copolymer of ethylene and 1,3-butadiene; the name PCHD is used to designate a homopolymer of 1,3-cyclohexadiene; the name PE is used to designate a homopolymer of ethylene; the name Mes is used to designate the mesityl group.

[0115] Size exclusion chromatography (SEC-HT):

[0116] Size-exclusion chromatography analyses of the entire PCHD group, the PCHD-Z>-EBR diblock copolymer, and the PCHD-Z>-EBR-Z>-PE triblock copolymer were performed using a Tosoh Bioscience Instrument (HLC-8321-GPC (HT-GPC)) equipped with two columns (TSKgel ultra-high-temperature columns with mixed pore size) and coupled to a refractometer detector. The exclusion limit of the columns was 4.0 x 10⁻⁴. 8 Da. The samples were prepared at a concentration of 3-5 mg mL' 1in 1,2,4-trichlorobenzene. The columns and detectors were maintained at 150°C. Sample volumes of 100 pL were injected and eluted with 1,2,4-trichlorobenzene (TCB) using a flow rate of 1 mL min⁻¹ 1 at a temperature of 150°C. The mobile phase was stabilized with 2,6-di(tert-butyl)-4-methylphenol (B HT) (0.2 g L 1 ). The dispersity D and the average molar masses by number and by mass (respectively M n and A7 W ) of polymers were determined from a conventional calibration using polystyrene standards using Tosoh's GPC Analysis software for data acquisition.

[0117] 2024PAT00122WO Differential Scanning Calorimetry (DSC):

[0118] DSC analyses are performed on a DSC 3+ instrument (Mettler Toledo) with sealed aluminum crucibles (40 pL) and under nitrogen flow (30 mL min' 1The temperature programs are as follows:

[0119] The thermograms of the PCHDs (examples 2 to 7) are obtained according to the following program: • step 1: ramp from 25 °C to 220 °C (10 °C min' 1 ), • step 2: isothermal at 220 °C for 5 min, • step 3: ramp from 220 °C to -80 °C (10 °C min) 1 ), • step 4: isothermal at -80 °C for 5 min, • step 5: ramp from -80 °C to 220 °C (10 °C min' 1 ), • step 6: isothermal at 220 °C for 5 min, • step 7: ramp from 220 °C to -80 °C (10 °C min' 1 ), • step 8: isothermal at -80 °C for 5 min, • step 9: ramp from -80 °C to 220 °C (10 °C min' 1 ). For examples 5 and 7, the program goes up to step 5. The glass transition temperatures (Tg) of the PCHDs reported in Table 1 were determined for all examples at step 5 (ramp -80 °C to 220 °C at 10 °C min' 1 ).

[0120] The thermogram of the PCHD-Z-EBR diblock copolymer (example 2) is obtained according to the following program: • step 1: ramp from 25 °C to 220 °C (10 °C min' 1 ), • step 2: isothermal at 220 °C for 5 min, • step 3: ramp from 220 °C to -80 °C (10 °C min) 1 ), • step 4: isothermal at -80 °C for 5 min, • step 5: ramp from -80 °C to 220 °C (10 °C min' 1 ), • step 6: isothermal at 220 °C for 5 min, • step 7: ramp from 220 °C to -80 °C (10 °C min' x ), • step 8: isothermal at -80 °C for 5 min, • step 9: ramp from -80 °C to 220 °C (10 °C min' x ). The glass transition temperatures (Tg) of the PCHD and EBR blocks reported in Table 1 were determined in step 5 (ramp -80 °C to 220 °C at 10 °C min' 1 ).

[0121] The thermograms of the triblock copolymers PCHD-Z>-EBR-Z>-PE (examples 3 to 7) are obtained according to the following program: • step 1: ramp from 25 °C to 220 °C (10 °C min' 1), • step 2: 5 min isotherm at 220 °C, • step 3: ramp from 220 °C to -80 °C (10 °C min' 1 ), • step 4: isothermal 5 min at -80 °C, • step 5: ramp from -80 °C to 220 °C (10 °C min' 1 ), • step 6: 5 min isotherm (220 °C), • step 7: ramp from 220 °C to -80 °C (10 °C min' 1 ), • step 8: 5-minute isothermal temperature at -80 °C • step 9: ramp from -80 °C to 220 °C (10 °C min' 1 ). For examples 5, 6 and 7 the program goes up to step 5. The glass transition temperatures (Tg) and melting temperatures (Tf) of the EBR and PE blocks respectively reported in Table 1 were determined in step 5 (ramp -80 °C to 220 °C at 10 °C min' 1 ) for examples 3, 5, 6 and 7; at step 9 (ramp -80 °C to 220 °C at 10 °C min' 1 ) for example 4.

[0122] All reactions sensitive to air and / or humidity are carried out under an argon atmosphere.

[0123] The dry polymerization solvents (methylcyclohexane and cyclohexane) are drawn from the solvent fountain (SPS800 MBraun). The cyclohexane was stored in a glove box on a molecular sieve (3 Å) before use.

[0124] 1,3-Cyclohexadiene (abcr) is dried for 24 hours on CaH2 under an argon atmosphere and then distilled under vacuum. Ethylene (grade N35, Air Liquide) is used without purification. 1,3-Butadiene is previously purified on an Axens alumina purification column and stabilized with 60 ppm of 4-tert-butylcatechol (TBC). To remove the TBC and traces of residual water, it is further purified by contact with trioctylaluminium for 30 minutes before use.

[0125] 2024PAT00122WO γ-Butyllithium (1.6 M in hexane, Sigma-Aldrich) is used as received. Tetramethylethylenediamine (TMEDA) is dried for 24 h on CalCE under an argon atmosphere, then distilled under vacuum and stored on a molecular sieve (3 Å). 2-Mesityl-magnesium bromide (BMM, IM in Et2Û, Sigma-Aldrich) is used as received. The {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex is prepared according to the protocol described in patent application WO 2007054224 A2.

[0126] 2,2'-Methylenebis(6-tert-butyl-4-methylphenol) (di-BHT, Sigma-Aldrich) is used in solution in toluene (10 g / L). Acetone (technical grade) is used to precipitate the polymers.

[0127] The reactor used in steps 2 is a 250 mL glass reactor equipped with a stirring wheel (anchor).

[0128] Example 1: Synthesis according to the invention of a PCHD-Z>-EBR diblock polymer:

[0129] Step 1: Anionic polymerization of 1,3-cyclohexadiene and preparation of the organomagnesium compound with the formula PCHD-MgMes:

[0130] In a conditioned Schlenk tube (3 vacuum-argon cycles), 25 mL of cyclohexane (solvent / monomer ratio 7.8), 0.156 mL (0.25 mmol) of w-BuLi (1.6 M in hexane), and 28 µL (0.1875 mmol, 0.75 equivalent) of TMEDA are introduced. The mixture is stirred at 40°C for 10 min, then 2.5 g of 1,3-cyclohexadiene is added. The solution turns yellow instantly, and the reaction mixture is stirred at 40°C for 120 min. The transmetallation reaction is then carried out with the addition of 0.3 mL (0.3 mmol, 1.2 equivalents) of BMM to obtain an organomagnesium compound with the formula R-Mg-A, where A is a poly(1,3-cyclohexadiene) (PCHD) and R is the mesityl group (Mes). The mixture is then transferred using a cannula under argon flow into the reactor, which has been pre-conditioned and heated to 90°C.

[0131] Step 2: Formation of the PCHD-Z>-EBR diblock copolymer:

[0132] 39.4 mg (62 pmol of Nd) of the Nd complex {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 are weighed in a glove box into a 50 mL flask. 175 mL of MCH (VMCH + V cyc 200 mL of iohexane is transferred from the solvent fountain into a 250 mL flask. 0.24 mL (0.24 mmol) of BMM is added to the MCH. The (MCH + BMM) solution is stirred for 5 min, then the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex is added. The catalytic solution is transferred via a cannula under argon flow into the reactor already containing the PCHD-MgMes solution. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). -1The reactor is then pressurized to 4 bar with an ethylene / l,3-butadiene mixture with an 80 / 20 molar ratio. The time to reach the desired temperature is considered to be when the medium has reached 89°C. The pressure is maintained constant in the reactor using a reservoir containing the ethylene / l,3-butadiene mixture, and polymerization is carried out at 90°C. Monomer consumption is monitored by the pressure drop in the reservoir until the desired consumption is reached. The reactor is then carefully depressurized and degassed under a flow of argon, and the medium is deactivated by the addition of EtOH (approximately 0.5 mL) and then cooled to room temperature. The copolymer is then precipitated in 600 mL of acetone before being collected in an aluminum capsule. 50 mL of a solution (10 g L 1 ) of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) are added to

[0133] 2024PAT00122WO copolymer is then evaporated under vacuum at 70°C for 7 hours. The PCHD-e-EBR diblock copolymer is weighed and analyzed.

[0134] Comparative example 1: Synthesis not in accordance with the invention of a diblock polymer PCHD-Z>- EBR:

[0135] The same experimental conditions as for example 1 were implemented, with the difference being the quantity of TMEDA, which is 1.25 equivalent of w-BuLi.

[0136] The results of Example 1 and Comparative Example 1 are shown in Table 1. Mn and Tg of the PCHD block are measured on a sample taken at the end of step 1.

[0137] Table 1:

[0138] Example 2: Synthesis according to the invention of a PCHD-Z>-EBR diblock polymer:

[0139] Step 1: Anionic polymerization of 1,3-cyclohexadiene and preparation of the organomagnesium compound with formula PCHDMgMes:

[0140] In a conditioned Schlenk tube (3 vacuum-argon cycles), 25 mL of cyclohexane (rhs-to-mmonomer ratio = 7.8), 0.156 mL (0.25 mmol) of w-BuLi (1.6 M in hexane), and 28 µL (0.1875 mmol, 0.75 equivalent) of TMEDA are introduced. The mixture is stirred at 40°C for 10 min, then 2.5 g of 1,3-cyclohexadiene is added. The solution turns yellow instantly, and the reaction mixture is stirred at 40°C for 120 min. The transmetallation reaction is then carried out with the addition of 0.3 mL (0.3 mmol, 1.2 equivalents) of BMM to obtain an organomagnesium compound with the formula R-Mg-A, where A is a poly(1,3-cyclohexadiene) (PCHD) and R is the mesityl group (Mes). The mixture is then transferred using a cannula under argon flow into the reactor, which has been pre-conditioned and heated to 90°C.

[0141] Step 2: Formation of the PCHD-Z>-EBR diblock copolymer. 39.4 mg (62 pmol of Nd) of the Nd complex {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 are weighed in a glove box into a 50 mL flask. 175 mL of MCH (VMCH + V cyc 200 mL of iohexane was taken from the solvent fountain into a 250 mL flask. 0.24 mL (0.24 mmol) of BMM was added to the

[0142] 2024PAT00122WO MCH. The (MCH + BMM) solution is stirred for 5 min, then the Nd {Me2Si(Ci3Hs)2Nd(BH4)2 i(THF)}2 complex is added. The catalytic solution is transferred using a cannula under argon flow into the reactor already containing the PCHD-MgMes solution. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). 1The reactor is then pressurized to 4 bar with an ethylene / l,3-butadiene mixture with an 80 / 20 molar ratio. The time to reaction is considered when the medium has reached a temperature of 89 °C. The pressure is maintained constant in the reactor using a reservoir containing the ethylene / l,3-butadiene mixture, and polymerization is carried out at 90 °C. Monomer consumption is monitored by the pressure drop in the reservoir until the desired consumption is reached. The reactor is then carefully depressurized and degassed under a flow of argon, and the medium is deactivated by the addition of EtOH (approximately 0.5 mL) and then cooled to room temperature. The copolymer is then precipitated in 600 mL of acetone before being collected in an aluminum capsule. 50 mL of a solution (10 g L 1) of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) are added to the copolymer, and then the solvent is evaporated under vacuum at 70°C for 7 hours. The dibloc PCHD-ε-EBR copolymer is weighed and analyzed.

[0143] Example 3: Synthesis according to the invention of a triblock polymer PCHD-Z>-EBR-Z>-PE:

[0144] Step 1: Anionic polymerization of 1,3-cyclohexadiene and preparation of organomagnesium with the formula PCHD-MgMes:

[0145] In a conditioned Schlenk tube (3 vacuum-argon cycles), 25 mL of cyclohexane (rhs-to-mmonomer ratio = 7.8), 0.156 mL (0.25 mmol, 1 equivalent) of w-BuLi (1.6 M in hexane), and 28 µL (0.1875 mmol, 0.75 equivalent) of TMEDA are introduced. The mixture is stirred at 40°C for 10 min, then 2.5 g ([CHD] / [BuLi] = 125) of 1,3-cyclohexadiene are added. The solution turns yellow instantly. The reaction mixture is stirred at 40°C for 120 min. The transmetallation reaction is then carried out with the addition of 0.3 mL (0.3 mmol, 1.2 equivalents) of BMM to obtain an organomagnesium compound with the formula R-Mg-A, where A is a poly(1,3-cyclohexadiene) (PCHD) and R is the mesityl group (Mes). The mixture is then transferred using a cannula under argon flow into the reactor, which has been pre-conditioned and heated to 90°C.

[0146] Step 2: Formation of the PCHD-Z>-EBR Z>-PE triblock copolymer:

[0147] 40 mg (63 pmol of Nd) of the Nd{Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex are weighed in a glove box into a 50 mL flask. 175 mL of MCH (VMCH + V cyc 200 mL of iohexane is taken from the solvent fountain into a 250 mL flask. 0.24 mL (0.24 mmol) of BMM is added to the MCH. The (MCH + BMM) solution is stirred for 5 min before the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex is added. The catalytic solution is transferred using a cannula under argon flow into the reactor already containing the PCHD-MgMes solution. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). 1The reactor is then pressurized to 4 bar with an ethylene / l,3-butadiene mixture with an 80 / 20 molar ratio. The target temperature is considered to be 89°C. The pressure is maintained constant in the reactor using a reservoir containing the ethylene / l,3-butadiene mixture. Monomer consumption is monitored by lowering the pressure in the reservoir until the desired consumption is reached. The reactor is

[0148] 2024PAT00122WO is then isolated and the remaining monomers are consumed until the pressure reaches 2.5 bar to obtain the EBR copolymer of M ndesired quantity and in parallel the reservoir is conditioned by 2 vacuum-ethylene cycles then pressurized with 100% ethylene. The reactor is then pressurized to 4 bar and supplied with ethylene. After consuming the desired quantity of ethylene, the reactor is carefully depressurized and degassed under an argon flow, and the medium is deactivated by adding EtOH (approximately 0.5 mL) and then cooled to room temperature. The copolymer is then precipitated in 600 mL of acetone before being collected in an aluminum capsule. 50 mL of a solution (10 g L 1 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) antioxidant is added to the copolymer, and then the solvent is evaporated under vacuum at 70°C for 7 hours. The triblock copolymer PCHD-Z>-EBR-Z>-PE is weighed and analyzed.

[0149] Example 4: Synthesis according to the invention of a triblock polymer PCHD-Z>-EBR-Z>-PE:

[0150] Step 1: Anionic polymerization of 1,3-cyclohexadiene and preparation of the organomagnesium compound with formula PCHDMgMes:

[0151] In a conditioned Schlenk tube (3 vacuum-argon cycles), 25 mL of cyclohexane (rhs-to-mmonomer ratio = 7.8), 0.156 mL (0.25 mmol, 1 equivalent) of w-BuLi (1.6 M in hexane), and 28 µL (0.1875 mmol, 0.75 equivalent) of TMEDA are introduced. The mixture is stirred at 40°C for 10 min, then 2.5 g ([CHD] / [w-BuLi] = 125) of 1,3-cyclohexadiene are added. The solution turns yellow instantly. The reaction mixture is stirred at 40°C for 90 min. The transmetallation reaction was subsequently carried out with the addition of 0.3 mL (0.3 mmol, 1.2 equivalents) of BMM to obtain an organomagnesium compound with the formula R-Mg-A, where A is a poly(1,3-cyclohexadiene) (PCHD) and R is the mesityl group (Mes). An aliquot was taken and precipitated in ethanol. The mixture was then transferred using a cannula under argon flow into the reactor, which had been pre-conditioned and heated to 90°C.

[0152] Step 2: Formation of the PCHD-Z>-EBR-Z>-PE triblock copolymer:

[0153] 42 mg (66 pmol of Nd) of the Nd complex {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 are weighed in a glove box into a 50 mL flask. 175 mL of MCH (VMCH + V cyc 200 mL of iohexane is taken from the solvent fountain into a 250 mL flask. 0.24 mL (0.24 mmol) of BMM is added to the MCH. The (MCH + BMM) solution is stirred for 5 min before the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex is added. The catalytic solution is transferred using a cannula under argon flow into the reactor already containing the PCHDMgMes solution. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). 1The reactor is then pressurized to 4 bar with an ethylene / l,3-butadiene mixture with an 80 / 20 molar ratio. The temperature at which the solution reaches 89°C is considered to be reached. The pressure is maintained constant in the reactor using a reservoir containing the ethylene / l,3-butadiene mixture. Monomer consumption is monitored by lowering the pressure in the reservoir until the desired level is reached. The reactor is then isolated, and the remaining monomers are consumed until the pressure reaches 2.5 bar to obtain the EBR copolymer of M n desired temperature is reached, and in parallel, the tank is conditioned by two vacuum-ethylene cycles and then pressurized with 100% ethylene. The reactor is

[0154] 2024PAT00122WO is then pressurized to 4 bar and supplied with ethylene. After consuming the desired amount of ethylene, the reactor is carefully depressurized and degassed under a flow of argon, and the medium is deactivated by adding EtOH (approximately 0.5 mL) and then cooled to room temperature. The copolymer is then precipitated in 600 mL of acetone before being collected in an aluminum capsule. 50 mL of a solution (10 g L 1 ) of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) are added to the copolymer, and then the solvent is evaporated under vacuum at 70°C for 7 hours. The triblock copolymer PCHD-Z>-EBR-Z>-PE is weighed and analyzed.

[0155] Example 5: Synthesis according to the invention of a triblock polymer PCHD-Z>-EBR-Z>-PE:

[0156] Step 1: Anionic polymerization of 1,3-cyclohexadiene and preparation of organomagnesium with the formula PCHD-MgMes:

[0157] In a conditioned Schlenk tube (3 vacuum-argon cycles), 25 mL of cyclohexane (rhs-to-mmonomer ratio = 7.8), 0.156 mL (0.25 mmol, 1 equivalent) of w-BuLi (1.6 M in hexane), and 28 µL (0.1875 mmol, 0.75 equivalent) of TMEDA are introduced. The mixture is stirred at 40°C for 15 min, then 2.5 g ([CHD] / [w-BuLi] = 125) of 1,3-cyclohexadiene are added. The solution turns yellow instantly. The reaction mixture is stirred at 40°C for 60 min. The transmetallation reaction is subsequently carried out with the addition of 0.3 mL (0.3 mmol, 1.2 equivalents) of BMM to obtain an organomagnesium compound of formula R-Mg-A, in which A is a poly(1,3-cyclohexadiene) (PCHD) and R is the mesityl group. An aliquot was taken and precipitated in ethanol. The medium containing the organomagnesium compound of formula PCHD-MgMes is used in step 2 as described below.

[0158] Step 2: Formation of the PCHD-Z>-EBR-Z>-PE triblock copolymer:

[0159] 38.4 mg (60 pmol of Nd) of the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex are weighed in a glove box in a 50 mL flask. 175 mL of MCH (VMCH + V cyc 200 mL of iohexane is taken from the solvent fountain into a 250 mL flask. 0.24 mL (0.24 mmol) of BMM is added to the MCH. The (MCH + BMM) solution is stirred for 5 min before the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex is added. The solution containing the organomagnesium compound with the formula PCHD-MgMes is added to the catalytic solution before its transfer, using a cannula under argon flow, into the reactor, which has been previously conditioned and heated to 90°C. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). 1The reactor is then pressurized to 4 bar with an 80 / 20 molar ethylene / butadiene mixture. The temperature at which the solution reaches 89°C is considered complete. The pressure is maintained constant in the reactor using a reservoir containing the ethylene / butadiene mixture. Monomer consumption is monitored by lowering the pressure in the reservoir until the desired level is reached. The reactor is then isolated, and the remaining monomers are consumed until the pressure reaches 2.5 bar to obtain the EBR copolymer of M n The desired volume is reached, and in parallel, the reservoir is conditioned by two vacuum-ethylene cycles and then pressurized with 100% ethylene. The reactor is then pressurized to 4 bar and supplied with ethylene. After consuming the desired amount of ethylene, the reactor is carefully depressurized and degassed under an argon flow, and the medium is deactivated by adding EtOH (~0.5 mL) and then cooled to room temperature.

[0160] 2024PAT00122WO The copolymer is then precipitated in 600 mL of acetone before being collected in an aluminum capsule. 50 mL of a solution (10 g L' 1 ) of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) are added to the copolymer, and then the solvent is evaporated under vacuum at 70°C for 7 h. The triblock copolymer PCHD-Z>-EBR-Z>-PE is weighed and analyzed. Example 6: Synthesis according to the invention of a triblock polymer PCHD-Z>-EBR-Z>-PE: The same experimental conditions as for Example 5 were implemented, with the difference being the amount of 1,3-cyclohexadiene (0.75 g, [CHD] / [«BuLi] = 38), cyclohexane (7.5 mL), and MCH (192.5 mL).

[0161] Example 7: Synthesis according to the invention of a triblock polymer PCHD-Z>-EBR-Z>-PE: The same experimental conditions as for example 5 were implemented with the difference of the quantity of 1,3-cyclohexadiene (1.5 g, [CHD] / [«BuLi] = 75), cyclohexane (15 mL) and MCH (185 mL).

[0162] The characteristics of the polymers in examples 2 to 7 are shown in Table 2. The catalytic activities in steps d) and e) are also given in Table 2. The Mn and Tg of the PCHD block are measured on a sample taken at the end of step 1.

[0163] Table 2:

[0164] 2024PAT00122WO

[0165] The examples demonstrate the ability of the process according to the invention to produce both diblock polymers of formula AB and triblock polymers ABC, where A is a poly(1,3-cyclohexadiene) block, B is a random copolymer of ethylene and 1,3-butadiene, and C is a polyethylene block. The process according to the invention has the advantage of producing block polymers containing an ethylene-rich diene block and a block with a very high Tg, in this case above 140°C, with good control of the macrostructure of the block polymers and with relatively high catalytic activities.

[0166] The presence of the Tg block above 120°C in block polymers according to the invention promises good thermal resistance of their mechanical properties, particularly at temperatures above 100°C.

[0167] 2024PAT00122WO

Claims

Demands 1. A process for the synthesis of a block polymer of formula AB-(C)n in which the symbol A represents a poly(1,3-cyclohexadiene) block, the symbol B represents a random copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C represents a polyethylene block, n being equal to 0 or 1, the 1,3-diene being an α-olefin, which process comprises: the sequence of steps a), b), c) and d) when n is equal to 0, the sequence of steps a), b), c) and d) followed by step e) when n is equal to 1, - step a) being the reaction in a hydrocarbon solvent of an organolithium compound and a multidentate polar agent in a ratio between the number of moles of the multidentate polar agent and the number of moles of the organolithium compound greater than 0.5 and less than 1 to form a complex consisting of a multidentate polar agent and an organolithium compound, - step b) being the anionic polymerization of 1,3-cyclohexadiene initiated by the complex consisting of a multidentate polar agent and an organolithium compound, in a hydrocarbon solvent, to form a poly(1,3-cyclohexadienyl)lithium, - step c) being the reaction between poly(l,3-cyclohexadienyl)lithium and a halide of an organomagnesium compound of formula (I) to form an organomagnesium compound of formula R-Mg-A, R-Mg-X (I) R comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by a methyl, an ethyl or an isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by a methyl, an ethyl or an isopropyl, the magnesium atom being in ortho position with respect to each of said two carbon atoms, where X is a halogen atom, and A represents a poly(1,3-cyclohexadiene) polymer chain, - step d) being the statistical polymerization of a monomer mixture containing ethylene and 1,3-diene, in the presence of a catalytic system comprising a metallocene of formula (II) and the organomagnesium compound of formula R-Mg-A, P(Cp 1 CP 2 )Nd(BH4)(i +y) .L y -N x (II) CP 1 and Cp 2 , identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted, P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom, L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium, N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0, - step e) being the subsequent homopolymerization of ethylene. 2024PAT00122WO 2. A process according to claim 1 wherein the organolithium compound is a butyllithium, preferably n-butyllithium.

3. A process according to claim 1 or 2 wherein the multidentate polar agent is N,N,N',N'-tetramethyl 1-enediamine.

4. A process according to any one of claims 1 to 3 wherein the hydrocarbon solvent in steps a) and b) is an aliphatic solvent, preferably cyclohexane, methylcyclohexane or a mixture thereof.

5. A method according to any one of claims 1 to 4 wherein the halide of an organomagnesium compound has the formula (la) Ri and Rs, whether identical or different, represent a methyl or an ethyl group, preferably a methyl group. R2, R3 and R4, identical or different, being a hydrogen atom or an alkyl, X being a halogen atom.

6. A method according to claim 5 wherein Ri and R5 each represent a methyl group and R2 and R4 each represent a hydrogen atom.

7. A method according to any one of claims 1 to 6 in which X represents a chlorine atom or a bromine atom, preferably a bromine atom.

8. A process according to any one of claims 1 to 7 wherein the monomer mixture containing ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene.

9. A method according to any one of claims 1 to 8 wherein the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes of which one is 1,3-butadiene.

10. A method according to any one of claims 1 to 9, wherein Cp 1 and Cp 2are chosen from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula CBHS, preferably each represent an unsubstituted fluorenyl group of formula CBHS.

11. A method according to any one of claims 1 to 10, wherein the bridge P conforms to the formula ZR X R 2 , Z representing a silicon or carbon atom, R 1 and R 2 , identical or different, each representing an alkyl group comprising from 1 to 20 carbon atoms, preferably a methyl.

12. A process according to any one of claims 1 to 11 wherein the metallocene is of formula (II-1), (II-2), (II-3), (II-4) or (II-5): [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] (II-l) [{Me2SiFlu2Nd(p-BH4)2Li(THF)}2] (II-2) [Me2SiFlu2Nd(p-BH4)(THF)] (II-3) [{Me2SiFlu2Nd(p-BH4)(THF)}2] (II-4) 2024PAT00122WO [Me2SiFlu2Nd(n-BH4)] (II-5) the Flu symbol representing the CBHS group.

13. A method according to any one of claims 1 to 12 wherein the poly(1,3-cyclohexadiene) block has a glass transition temperature greater than 120°C, preferably greater than 140°C.

14. Block polymer of formula AB or ABC, the symbol A representing a poly(1,3-cyclohexadiene) block with a glass transition temperature above 120°C, preferably above 140°C, the symbol B representing a statistical copolymer block comprising units of a 1,3-diene and more than 50 mole percent of ethylene units, and the symbol C representing a polyethylene block, the 1,3-diene being an α-olefin.

15. Block polymer according to claim 14 in which the symbol C represents a polyethylene block with a melting temperature above 90°C, preferably above 100°C. 2024PAT00122WO

Images