Diblock polymers consisting of a poly(1,3-cyclohexadiene) block and a random copolymer block based on ethylene and a 1,3-diene

Abstract

The invention relates to a diblock polymer of formula A-B, where symbol A represents a thermoplastic block which is a poly(1,3-cyclohexadiene) having a number-average molar mass greater than 2,000 g / mol and less than 40,000 g / mol, symbol B represents an elastomeric block which is a random copolymer comprising units of a 1,3-diene and more than 50 mol% of ethylene units, the 1,3-diene being an α-olefin, in particular 1,3-butadiene.

Description

[0001] Diblock polymers consisting of 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 diblock polymers containing a thermoplastic hydrocarbon polymer block and an ethylene-rich diene statistical elastomer block.

[0003] Statistical 1,3-diene and ethylene elastomers containing more than 50 mole percent ethylene units are known in the prior art, particularly in the field of tire treads. To modify the properties of these elastomers, it has been proposed to form diblocks by introducing a thermoplastic block at one end of the elastomer, as described, for example, in documents WO 2019077235 and WO 2021123590. The introduction of a thermoplastic block such as polystyrene increases the low-strain moduli of the elastomer. However, it also results in a significant decrease in the elastomer's plasticity, which can be a disadvantage, particularly in elastomer forming operations. Therefore, there is a need to improve the plasticity of block polymers containing a thermoplastic block and a statistical diene elastomer block rich in ethylene.

[0004] The inventors discovered that introducing a thermoplastic poly(l,3-cyclohexadiene) block with a number-average molar mass greater than 2000 g / mol and less than 40000 g / mol into an ethylene-rich diene elastomer instead of a polystyrene block yields a diblock polymer exhibiting better plasticity than the diblock containing a polystyrene block.

[0005] A first object of the invention is a diblock polymer of formula AB, the symbol A representing a thermoplastic block which is a poly(l,3-cyclohexadiene) of number-average molar mass greater than 2000 g / mol and less than 40000 g / mol, the symbol B representing an elastomer block which is a statistical copolymer comprising units of a 1,3-diene and more than 50% by mole of ethylene units, the 1,3-diene being an α-olefin.

[0006] A second object of the invention is a composition comprising a dibloc polymer according to the invention and another ingredient.

[0007] Detailed description:

[0008] Any range of values ​​designated by the expression "between a and b" represents the range of values ​​greater than "a" and less than "b" (i.e., bounds a and b excluded) while any 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).

[0009] The compounds mentioned in the description can be of fossil origin or bio-based. In the latter case, they may be derived, partially or entirely, 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 derived, partially or entirely, from a process

[0010] 2024PAT00106WO from recycling, or obtained from raw materials themselves derived from a recycling process.

[0011] The block represented by the symbol B in formula AB represents an elastomer block containing ethylene units and 1,3-diene units. This elastomer block is a statistical copolymer, meaning that the monomer units constituting the elastomer block are statistically distributed within it. The block represented by the symbol A is a thermoplastic polymer, a homopolymer of 1,3-cyclohexadiene, also known as poly(1,3-cyclohexadiene).

[0012] An ethylene unit is known to be a unit with the repeating pattern -(CH2-CH2)-. The ethylene units present in the elastomer block represent more than 50% by mole of the monomer units constituting the elastomer block. In this application, the proportion of ethylene units in the elastomer block, that is, the number of moles of ethylene units in the elastomer block, is expressed as a mole percentage relative to the number of moles of monomer units constituting the elastomer block.

[0013] According to any one embodiment of the invention, the elastomer block is preferably a random copolymer of ethylene and a 1,3-diene, in which case the monomer units of the elastomer block are those resulting from the copolymerization of ethylene and the

[0014] 1.3-diene and are statistically distributed in the elastomer block.

[0015] The 1,3-diene whose monomeric units constitute the elastomer 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 1,3-diene" refers to one or more 1,3-dienes, that is, at least two 1,3-dienes. 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. More preferably, the 1,3-diene is 1,3-butadiene. Most preferably, the elastomer block is a random copolymer of ethylene and

[0016] 1,3-butadiene.

[0017] As is known, a 1,3-diene can insert itself into a growing polymer chain by a 1,4 or 2,1 or even 3,4 insertion in the case of substituted dienes such as isoprene to give rise respectively to the formation of 1,3-diene units of configuration 1,4, 1,3-diene units of configuration 1,2 or of configuration 3,4. Preferably, the 1,3-diene units in the configuration 1,2 and the 1,3-diene units in the configuration 3,4 represent more than 50% by mole of the 1,3-diene units.

[0018] According to one embodiment of the invention, the elastomer block contains 1,3-diene units of configuration 1,4, preferably Al cin. Preferably, the 1,3-diene units of configuration α-trans represent more than 50% by mole of the 1,3-diene units of configuration 1,4. More preferably, the 1,3-diene units of configuration 1,4-trans represent 100% by mole of the 1,3-diene units of configuration 1,4.

[0019] According to a particularly preferred embodiment of the invention, the elastomer block contains 1,3-diene units that are more than 50% by mole of configuration units

[0020] 2024PAT00106WO 1,2 or 3,4, the complement to 100% of the units of 1,3-diene being units of configuration 1,4-trans.

[0021] According to another particularly preferred embodiment of the invention, especially when the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes, one of which is 1,3-butadiene, the elastomer block further contains 1,2-cyclohexane or 1,4-cyclohexane motifs, preferably 1,2-cyclohexane motifs. The presence of these cyclic structures in the elastomer block results from a very specific insertion of ethylene and 1,3-butadiene during their copolymerization. The mechanism for obtaining such a microstructure is described, for example, in Macromolecules 2009, 42, 3774-3779. The 1,2-cyclohexane and 1,4-cyclohexane motif content of the elastomer block varies according to the respective ethylene and 1,3-butadiene contents of the elastomer block. Preferably, it is less than or equal to 15%, a molar percentage expressed relative to the number of moles of monomer units constituting the elastomer block.The elastomer block typically contains less than 10 mole percent of the 1,2-cyclohexane and 1,4-cyclohexane repeating units at the highest ethylene concentrations in the block, and may contain more than 10 mole percent at the lowest ethylene concentrations, for example, up to 15 mole percent. This percentage is expressed relative to the number of moles of monomer units constituting the elastomer block. The 1,2-cyclohexane repeating unit has the following formula.

[0022] Since the stiffness of a diblock polymer increases with the proportion of ethylene units in the elastomer block, a diblock polymer with a particularly high proportion of ethylene units in the elastomer block may be sought for applications where high material stiffness is required. Preferably, the ethylene units in the elastomer block represent at least 60 mole percent of the units constituting the elastomer block, in which case the elastomer block comprises at least 60 mole percent of ethylene units. Preferably, the ethylene units in the elastomer block represent at most 85 mole percent of the units constituting the elastomer block, in which case the elastomer block contains at most 85 mole percent of ethylene units.

[0023] Preferably, the elastomer block has a glass transition temperature (Tg) below -10°C, preferably between -90°C and -10°C. More preferably, the glass transition temperature of the elastomer block is between -70°C and -20°C, advantageously between -50°C and -20°C. The glass transition temperature of the elastomer block can be adjusted, for example, by the chemical structure of 1,3-diene, specifically the respective proportions of ethylene and 1,3-diene units in the elastomer block.

[0024] The elastomer block has a number-average molar mass preferably greater than or

[0025] 2024PAT00106WO equal to 50,000 g / mol. The elastomer block preferably has a number-average molar mass less than or equal to 150,000 g / mol. According to a preferred embodiment of the invention, the elastomer block has a number-average molar mass greater than or equal to 50,000 g / mol and less than or equal to 150,000 g / mol.

[0026] According to another preferred embodiment of the invention, the elastomer block has a number-average molar mass ranging from 50,000 g / mol to 100,000 g / mol.

[0027] The thermoplastic block represented by the symbol A in formula AB has the essential characteristic of being a poly(l,3-cyclohexadiene) with a number-average molar mass greater than 2000 g / mol and less than 40000 g / mol. Preferably, the thermoplastic block has a number-average molar mass greater than 5000 g / mol. Preferably, the thermoplastic block has a number-average molar mass less than 30000 g / mol. Even more preferably, the thermoplastic block has a number-average molar mass greater than 5000 g / mol and less than 30000 g / mol.

[0028] The thermoplastic block preferably has a glass transition temperature above 120°C. A glass transition temperature above 120°C gives the diblock polymer better thermal resistance to its properties when exposed to temperatures exceeding 100°C. More preferably, the thermoplastic block has a glass transition temperature above 140°C.

[0029] The dibloc polymer has a number-average molar mass (Mn) preferentially between 50,000 g / mol and 200,000 g / mol, more preferably ranging from 60,000 g / mol to 150,000 g / mol, in particular ranging from 60,000 g / mol to 100,000 g / mol.

[0030] The diblock polymer according to the invention can be prepared by a process which comprises the sequence of steps a), b), c) and d):

[0031] - step a) being the reaction in a hydrocarbon solvent of an organolithium compound and a multidentate polar agent to form a complex consisting of a multidentate polar agent and an organolithium compound,

[0032] - 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,

[0033] - 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,

[0034] R-Mg-X (I)

[0035] 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,

[0036] where X is a halogen atom, and A represents a poly(1,3-cyclohexadiene) polymer chain,

[0037] - 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)

[0038] 2024PAT00106WO 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,

[0039] P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom,

[0040] L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium,

[0041] 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.

[0042] 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.

[0043] Organolithium compounds are commonly defined as compounds consisting of a carbon chain, preferably a hydrocarbon chain, with a carbon-lithium bond. Organolithium compounds are most commonly alkyllithium compounds. The alkyl group of an alkyllithium compound may contain one or more carbon atoms, that is, at least two. Organolithium compounds are most commonly butyllithium compounds, and even more commonly n-butyllithium compounds.

[0044] The multidentate polar agent is preferably a bidentate polar agent such as N,N,N',N'-tetramethylenediamine, 1,2-dipiperidinoethane, 1,4-diazabicyclo[2,2,2]octane (DABCO), more preferably N,N,N',N'-tetramethylenediamine.

[0045] Preferably, the ratio of the number of moles of the pluridendate polarizing agent to the number of moles of the organolithium compound in step a) is greater than 0.5 and less than 1. Using a ratio both greater than 0.5 and less than 1 is advantageous for obtaining a thermoplastic block with a glass transition temperature well above 100°C, particularly above 120°C. Furthermore, the preferred range of the ratio between the number of moles of the multidendate polarizing agent and the number of moles of the organolithium compound in step a) is also favorable for accurately controlling the respective molar masses of the thermoplastic block and the elastomer block.

[0046] The hydrocarbon solvent in step a) is preferably an aliphatic solvent, more preferably cyclohexane, methylcyclohexane or a mixture thereof.

[0047] 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.

[0048] Poly(1,3-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.

[0049] The hydrocarbon solvent in step b) is preferably an aliphatic solvent, more

[0050] 2024PAT00106WO preferably cyclohexane, methylcyclohexane or a mixture thereof. Advantageously, the hydrocarbon solvent of step b) is that used in step a).

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] X preferably represents a chlorine atom or a bromine atom, more preferably a bromine atom. Preferably, Ri and R5 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 halide of an organomagnesium compound R-Mg-X is generally a solution in an ether, preferably diethyl ether or dibutyl ether. The concentration of poly(1,3-cyclohexadienyl)lithium is.

[0056] 2024PAT00106WO preferentially from 0.001 to 1 mol lithium equivalent / L, more preferably from 0.01 to 0.2 mol lithium equivalent / L, that of the organomagnesium solution R-Mg-X preferably from 1 to 5 mol / L, more preferably from 2 to 3 mol / L. The reaction between poly(1,3-cyclohexadienyl)lithium and the halide of an organomagnesium compound R-Mg-X is typically carried out at a temperature ranging from 0°C to 60°C. Contacting is preferably carried out at a temperature between 0°C and 23°C. As with any synthesis performed in the presence of organometallic compounds, contacting and the 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.

[0057] Once formed and without being separated from the reaction medium of step c), the organomagnesium 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).

[0058] Step d) consists of forming a statistical copolymer block comprising 1,3-diene units and more than 50 mol% ethylene units. Step d) is the statistical polymerization of a monomer mixture containing ethylene and 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 with the formula R-Mg-A. The organomagnesium compound with the formula R-Mg-A obtained in step c) is used as a cocatalyst for the catalytic system in step d). It is generally used in step d) without being separated from the reaction mixture of step c).

[0059] The metallocene used in the catalytic system has the formula (II) P(Cp 1 CP 2 )Nd(BH4)(i+ y) -L y -Nx (II)

[0060] 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,

[0061] P being a group bridging the two groups Cp 1 and Cp 2 and comprising a silicon or carbon atom,

[0062] L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium,

[0063] 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.

[0064] 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 SiR x R 2 , R 1 and R 2 , being identical and as defined previously. Even more preferably, P satisfies the formula SiMe?.

[0065] 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 accessibility of the molecules.

[0066] 2024PAT00106WO corresponding to cyclopentadienes and substituted fluorenes, because the latter are commercially available or easily synthesized.

[0067] 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, for 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 shown in the diagram below.

[0068] 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.

[0069] 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 the 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.

[0070] 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.

[0071] 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.

[0072] WO 2007054224. Metallocene can be prepared in a traditional way by a process

[0073] 2024PAT00106WO is analogous to that described in patent application WO 2007054224, in particular by reacting, under inert and anhydrous conditions, the salt of an alkali metal of the ligand with a rare-earth borohydride 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 the reaction, the metallocene is separated from the reaction byproducts by techniques known to those skilled in the art, such as filtration or precipitation in a second solvent. The metallocene is then dried and isolated in solid form.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 2024PAT00106WO 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. Preferably, the monomer mixture containing ethylene and 1,3-diene contains less than 90 mol% ethylene. More preferably, the monomer mixture containing ethylene and 1,3-diene contains at most 85 mol% ethylene.

[0080] 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.

[0081] 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).

[0082] At the end of step d), polymerization is stopped by deactivating the active polymerization sites, for example by cooling the polymerization medium or by adding an alcohol, preferably one containing 1 to 3 carbon atoms, such as ethanol. The diblock polymer can be recovered using conventional techniques known to those skilled in the art, such as precipitation, evaporation of the solvent under reduced pressure, or steam stripping.

[0083] Advantageously, the sequence of steps a), b), c), d) 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) can be carried out continuously or discontinuously.

[0084] The diblock polymer according to the invention can be used in a composition, another object of the invention, which typically comprises another ingredient. The other ingredient may be a filler such as carbon black or silica, a plasticizer such as oil, a crosslinking agent such as sulfur or peroxide, an antioxidant, or a polymer other than the diblock polymer according to the invention. The composition may be a rubber composition.

[0085] In summary, the invention is preferably implemented according to any one of the following embodiments 1 to 18:

[0086] Mode 1: Diblock polymer of formula AB, the symbol A representing a thermoplastic block which is a poly(l,3-cyclohexadiene) of number-average molar mass greater than 2000 g / mol and less than 40000 g / mol, the symbol B representing an elastomer block which is a statistical copolymer comprising units of a 1,3-diene and more than 50% by mole of ethylene units, the 1,3-diene being an α-olefin.

[0087] 2024PAT00106WO Mode 2: Polymer diblock according to mode 1 in which the elastomer block comprises at most 85 mole percent of ethylene units.

[0088] Mode 3: Polymer diblock according to mode 1 or 2 in which the elastomer block comprises at least 60 mole percent of ethylene units.

[0089] Mode 4: Diblock polymer according to any one of modes 1 to 3 in which the elastomer block is a statistical copolymer block of ethylene and a 1,3-diene.

[0090] Mode 5: Diblock polymer according to any one of modes 1 to 4 in which the 1,3-diene is 1,3-butadiene or isoprene or a mixture of 1,3-dienes of which one is 1,3-butadiene.

[0091] Mode 6: Diblock polymer according to any one of modes 1 to 5 in which the 1,3-diene is 1,3-butadiene.

[0092] Mode 7: Diblock polymer according to any one of modes 1 to 6 in which the elastomer block is a random copolymer of ethylene and 1,3-butadiene.

[0093] Mode 8: Diblock polymer according to mode 6 or 7 in which the elastomer block further contains 1,2-cyclohexane motifs or 1,4-cyclohexane motifs, preferably 1,2-cyclohexane motifs.

[0094] Mode 9: Diblock polymer according to mode 8 in which the content of 1,2-cyclohexane motif and 1,4-cyclohexane motif of the elastomer block is less than or equal to 15%, molar percentage expressed in relation to the number of moles of monomer units constituting the elastomer block.

[0095] Mode 10: Diblock polymer according to any one of modes 1 to 9 in which the elastomer block has a number-average molar mass greater than or equal to 50000 g / mol.

[0096] Mode 11: Diblock polymer according to any one of modes 1 to 10 in which the elastomer block has a number-average molar mass less than or equal to 150000 g / mol.

[0097] Mode 12: Diblock polymer according to any one of modes 1 to 11 in which the thermoplastic block has a number-average molar mass greater than 5000 g / mol.

[0098] Mode 13: Diblock polymer according to any one of modes 1 to 12 in which the thermoplastic block has a number-average molar mass less than 30000 g / mol.

[0099] Mode 14: Diblock polymer according to any one of modes 1 to 13 in which the thermoplastic block has a glass transition temperature greater than 120°C.

[0100] Mode 15: Diblock polymer according to any one of modes 1 to 14 in which the thermoplastic block has a glass transition temperature greater than 140°C.

[0101] Mode 16: Diblock polymer according to any one of modes 1 to 15 which has a number-average molar mass between 50,000 g / mol and 200,000 g / mol.

[0102] 2024PAT00106WO Mode 17: Diblock polymer according to any one of modes 1 to 16 which has a number-average molar mass ranging from 60,000 g / mol to 150,000 g / mol.

[0103] Mode 18: Composition which includes a diblock polymer according to any one of modes 1 to 17 and another ingredient.

[0104] 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 and not limitation.

[0105] Examples

[0106] 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 PS is used to designate a homopolymer of polystyrene; the name Mes is used to designate the mesityl group.

[0107] Size exclusion chromatography (SEC-THF):

[0108] Size-exclusion chromatography analyses of polystyrene homopolymers and PS-Z>-EBR diblock polymers were performed using a Viscotek TDmax instrument (Malvem Instruments) equipped with a guard column and three columns (SDVB, 5 µm, 330 x 7.5 mm, Polymer Standards) and three detectors (refractometer, viscometer, and light scatterer). Samples were prepared at a concentration of 3–4 mg mL⁻¹ 1 in THF and filtered through a 0.45 µm PTFE membrane and the analyses are carried out at 40 °C in stabilized THF at a flow rate of 1 mL min' 1 The data are acquired and processed using OmniSEC 5.02 software. The number-average molar masses (Mn) of the copolymers are determined using conventional calibration obtained from polystyrene standards (800 - 2,500,000 g mol⁻¹). 1 ), Polymer Standard Service (Mainz) using the refractometer detector. The dispersity Σ) (Σ) = Mw / Mn) is also determined.

[0109] Size exclusion chromatography (SEC-HT):

[0110] Size-exclusion chromatography analyses of the entire PCHD group and the PCHD-Z-EBR diblock copolymers 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' 1 in 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 (BHT) (0.2 g L 1 The dispersity D (D = M Vi IM a) and the average number and mass molar masses (respectively M n etM^) of the polymers were determined from a conventional calibration using polystyrene standards using Tosoh's GPC Analysis software for data acquisition.

[0111] 2024PAT00106WO Differential Scanning Calorimetry (DSC):

[0112] DSC analyses are performed on a DSC 3+ instrument (Mettler Toledo) with sealed aluminum crucibles (40 pL) and under nitrogen flow (30 mL min' 1 The temperature programs are as follows:

[0113] PCHD thermograms 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 ). The glass transition temperatures (Tg) of the PCHDs reported in Table 1 were determined in step 5 (ramp -80 °C to 220 °C at 10 °C min' 1 ).

[0114] The thermogram of the PCHD-Z-EBR diblock copolymer (example 1) 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 EBR blocks reported in Table 1 were determined in step 5 (ramp -80 °C to 220 °C at 10 °C min' 1 ).

[0115] The thermogram of the dibloc copolymer PS-Z>-EBR (example 2) is obtained according to the following program: • step 1: ramp from 25 °C to 180 °C (10 °C min' 1 ), • step 2: 5 min isotherm at 180 °C, • step 3: ramp from 180 °C to -80 °C (10 °C min' 1 ), • step 4: isothermal 5 min at -80 °C, • step 5: ramp from -80 °C to 180 °C (10 °C min' 1 ), • step 6: 5 min isotherm (180 °C), • step 7: ramp from 180 °C to -80 °C (10 °C min' 1 ), • step 8: 5-minute isothermal temperature at -80 °C • step 9: ramp from -80 °C to 180 °C (10 °C min' 1 ). The glass transition temperatures (Tg) and melting temperatures (Tf) of the EBR and PE blocks respectively reported in Table 1 were determined in step 9.

[0116] Tensile tests:

[0117] Tensile testing is performed on an MTS Criterion C42 tensile tester at the temperature of the sample being analyzed (20-25°C), equipped with a 50 N load cell and a cross-sectional speed of 500 mm / min. The materials are pressed at 150°C under 4-5 tons in an 80 mm x 60 mm x 1.5 mm mold. Standard H2 type specimens (usable dimensions 30 mm x 4 mm) are cut at room temperature using a suitable die.

[0118] Polymer preparation:

[0119] All reactions sensitive to air and / or humidity are carried out under an argon atmosphere.

[0120] 2-Methyltetrahydrofuran (MeTHF) was distilled over sodium / benzophenone. The dry polymerization solvents (methylcyclohexane and cyclohexane) were collected from the solvent fountain (SPS800 MBraun). The cyclohexane was stored in a glove box on a molecular sieve (3 Å) before use.

[0121] 2024PAT00106WO 1,3-Cyclohexadiene (abcr) is dried for 24 hours on CaLL under an argon atmosphere and then distilled under vacuum. Styrene (Sigma-Aldrich) is dried for 24 hours on CaLL under an argon atmosphere and then distilled under vacuum. Ethylene (grade N35, Air Liquide) is used without purification. 1,3-Butadiene, previously purified on an "Axens" alumina purification column and stabilized with 60 ppm TBC, is purified by contact with trioctylaluminium for 30 minutes before use.

[0122] I-butyllithium (1.6M in hexane, Sigma-Aldrich) is used as received. Tetramethylethylenediamine (TMEDA) is dried for 24 h on CaLB under an argon atmosphere, then distilled under vacuum and stored on a molecular sieve (3 Å). The complex {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 is prepared according to the protocol described in patent application WO 2007054224 A2.

[0123] 2,2'-Methylenebis(6-tert-butyl-4-methylphenol) (di-BHT, Sigma-Aldrich) is used as received as an antioxidant. Acetone (technical grade) is used to precipitate the polymers.

[0124] The reactor used in steps 2 is a 250 mL glass reactor equipped with a stirring wheel (anchor).

[0125] Commercial 2-mesityl-magnesium bromide (BMM, IM in Et2Û, Sigma-Aldrich) is used as received.

[0126] Synthesis of 2-mesityl-magnesium bromide (BMMMeTHF, 0.5 M in toluene)

[0127] In a 100 mL round-bottom flask, a magnesium suspension (4.15 g, 3.4 equivalents) is activated with 30 mg of I₂ in 10 mL of MeTHF. A solution of 7.65 mL (50 mmol) of 2-bromomesitylene in 40 mL of MeTHF is added dropwise to this suspension with vigorous stirring. The temperature is set at 35–40°C. After two hours of reaction, the solution is filtered, and the solvent is evaporated, yielding an oily product (21.58 g). ¹H NMR confirms the formation of MesMgBr with a MeTHF / Mg ratio of 2.7. The product is solubilized in toluene to obtain a concentration of 0.5 M.

[0128] Example 1 according to the invention: PCHD-Z-EBR diblock polymer, PCHD mass fraction being 0.26:

[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 (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.

[0131] 2024PAT00106WO 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 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, then 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 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 h. The dibloc copolymer PCHD-ε-EBR is weighed and analyzed.

[0133] Example 2 not in accordance with the invention: PS-Z>-EBR dibloc polymer, PS mass fraction being 0.27

[0134] Step 1: Anionic polymerization of styrene and preparation of the organomagnesium compound with the formula PS-MgMes:

[0135] In an inert Schlenk tube, 40 mL of dry toluene and 5.5 mL of styrene (5 g, 48 mmol) are introduced. 0.22 mL of ethyl tetrahydrofurfuryl ether (0.3 M in toluene, 0.066 mmol) is added, followed by 0.21 mL of w-BuLi (1.6 M in hexane, 0.33 mmol). The solution turns red. The reaction mixture is stirred at 40 °C for 20 min, and then the transmetallation reaction is carried out with 0.8 mL of BMMMeTHF (0.4 mmol, 1.2 eq.) to obtain macro-ATC PS i5K-MgMes. An aliquot is taken and precipitated in ethanol. This solution is transferred under argon flow to the previously inert reactor.

[0136] Step 2: Formation of the PS-Z>-EBR diblock copolymer:

[0137] 32 mg (50 pmol Nd) of the Nd {Me2Si(Ci3H8)2Nd(BH4)2Li(THF)}2 complex are weighed into a 50 mL glovebox. 155 mL of toluene are taken from the solvent fountain into a 250 mL flask. 0.40 mL (0.20 mmol) of BMMMeTHF is added to the toluene. The 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 PSisK-MgMes solution. The reactor is isolated and the pressure reduced to 0.5 bar before starting stirring (1000 rpm). 1 The 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 have reached its target temperature. The pressure is maintained constant in the reactor using a reservoir containing the mixture.

[0138] 2024PAT00106WO ethylene / l,3-butadiene. Monomer consumption is monitored by the pressure drop in the reservoir until the desired consumption is reached. The reactor is then depressurized and degassed under argon flow, polymerization is deactivated by the addition of EtOH (approximately 0.5 mL), and the medium is cooled to room temperature. A few milligrams of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) are added, and the copolymer is precipitated in 400 mL of MeOH. The polymer is washed with methanol, then collected in a crystallizer and dried under vacuum at 80 °C for 4 hours. The PS-Z>-EBR diblock copolymer is weighed and analyzed.

[0139] Example 3 not in accordance with the invention: EBR polymer

[0140] 199 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into a 250 mL inert flask fitted with a magnetic stir bar. 0.19 mL of a 0.52 M butylmagnesium solution in heptane is introduced into the flask while stirring. 32.0 mg (50 pmol neodymium) of {(Me2Si(Ci3HQ2)Nd(q-BH4)[(q-BH4)Li(THF)] [2 are then introduced into the flask. The catalytic solution is cannulated into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar, and then the reactor is pressurized to 4 bar with an 80 / 20 mol / mol ethylene / butadiene mixture, and the temperature is simultaneously raised to 90 °C. The pressure is maintained constant in the reactor using a reservoir containing an 80 / 20 mol / mol ethylene / butadiene gaseous mixture.When the desired amount of monomers has been consumed, in this case after 12 g, the reactor is carefully depressurized and degassed under argon flow, and the medium is deactivated by adding EtOH (approximately 0.5 mL) and then cooled to room temperature. 0.2 g of the antioxidant 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (di-BHT) is added, and the copolymer is precipitated in 600 mL of MeOH. It is then collected in a crystallizer and dried under vacuum at 80–100 °C for 6 h.

[0141] The structure of the prepared polymers is identified by SEC and DSC analysis. The results are shown in Table 1. The Mn and Tg of the PCHD and PS blocks are measured on a sample taken at the end of step 1.

[0142] Table 1:

[0143] In examples 1 and 2, the diblock polymers have a thermoplastic block, respectively HDPE and PS, and an EBR elastomer block, with a similar mass fraction of the thermoplastic block. In example 3, the polymer is EBR, so the mass fraction of the thermoplastic block is 0.

[0144] 2024PAT00106WO The elongation at break of the PCHD-EBR diblock (example 1) and the maximum stress applied to it are compared to those of the PS-EBR diblock (example 2), at the same mass fraction of thermoplastic block in the diblock polymer. The EBR polymer from example 3 is used in the comparisons as a reference. The results are shown in Table 2. Table 2:

[0145] It has been observed that the introduction of a thermoplastic block into the EBR polymer significantly impacts both the maximum stress and the elongation at break of the polymer. However, the introduction of the PCHD block has a lesser impact than that of a PS block. Given the improved elongation at break, PCHD-EBR diblock polymers exhibit better plasticity than their PS-EBR counterparts.

[0146] 2024PAT00106WO

Claims

Demands 1. Diblock polymer of formula AB, the symbol A representing a thermoplastic block which is a poly(l,3-cyclohexadiene) of number-average molar mass greater than 2000 g / mol and less than 40000 g / mol, the symbol B representing an elastomer block which is a statistical copolymer comprising units of a 1,3-diene and more than 50% by mole of ethylene units, the 1,3-diene being an α-olefin.

2. Diblock polymer according to claim 1 in which the elastomer block comprises at most 85 mole percent of ethylene units.

3. Diblock polymer according to claim 1 or 2 in which the elastomer block comprises at least 60 mole percent of ethylene units.

4. Diblock polymer according to any one of claims 1 to 3 wherein the elastomer block is a statistical copolymer block of ethylene and a 1,3-diene.

5. Diblock polymer according to any one of claims 1 to 4 wherein the 1,3-diene is 1,3-butadiene or isoprene or a mixture of 1,3-dienes of which one is 1,3-butadiene.

6. Diblock polymer according to any one of claims 1 to 5 wherein the 1,3-diene is 1,3-butadiene.

7. Dibloc polymer according to any one of claims 1 to 6 wherein the elastomer block has a number-average molar mass greater than or equal to 50000 g / mol.

8. Dibloc polymer according to any one of claims 1 to 7 wherein the elastomer block has a number-average molar mass less than or equal to 150000 g / mol.

9. Dibloc polymer according to any one of claims 1 to 8 wherein the thermoplastic block has a number-average molar mass greater than 5000 g / mol.

10. Dibloc polymer according to any one of claims 1 to 9 wherein the thermoplastic block has a number-average molar mass of less than 30000 g / mol.

11. Diblock polymer according to any one of claims 1 to 10 wherein the thermoplastic block has a glass transition temperature greater than 120°C.

12. Diblock polymer according to any one of claims 1 to 11 wherein the thermoplastic block has a glass transition temperature greater than 140°C.

13. Diblock polymer according to any one of claims 1 to 12 which has a number-average molar mass of between 50,000 g / mol and 200,000 g / mol, more preferably from 60,000 g / mol to 150,000 g / mol.

14. Composition comprising a diblock polymer according to any one of claims 1 to 13 and another ingredient. 2024PAT00106WO

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