Synthesis of block polymers based on 1,3-dienes and ethylene

Abstract

The present invention relates to a process for the preparation of multi-block polymers by random copolymerization of a mixture comprising ethylene and a 1,3-diene followed by subsequent polymerization of ethylene in the presence of a rare earth metallocene and an organomagnesium compound R B -(Mg-R A )m-Mg-R B or X-Mg-R A -Mg-X, wherein R A is an aliphatic hydrocarbon divalent chain, optionally interrupted by one or more oxygen or sulfur atoms or arylene groups, R B comprises a benzene ring substituted by Mg atoms, said benzene ring being substituted by a methyl, ethyl or isopropyl group on one carbon atom located ortho relative to Mg, or forming a ring with the carbon atom located meta relative to Mg and closest thereto, the other carbon atom of the benzene ring located ortho relative to Mg being substituted by a methyl, ethyl or isopropyl group, X is a halogen atom, and m is a number greater than or equal to 1.

Description

Technical Field

[0001] The present invention pertains to methods for synthesizing “multiblock” block polymers based on 1,3-diene and ethylene, comprising at least three blocks. More specifically, the present invention pertains to block polymers comprising at least a first copolymer block and two other polyethylene blocks, the first copolymer block being based on ethylene and 1,3-diene, each polyethylene block being attached to a different end of the first block, the first block being a central block within the block polymer. Background Technology

[0002] EP 2599809 A1 describes the synthesis of multiblock polymers based on ethylene and 1,3-butadiene. These are synthesized via a first step of ethylene polymerization followed by a step of 1,3-butadiene polymerization. The multiblock polymers are also synthesized by repeatedly polymerizing the first monomer feed of ethylene and the second monomer feed of 1,3-butadiene. The block polymers are described as consisting of highly cis-polybutadiene blocks and polyethylene blocks, characterized by the glass transition temperature of the highly cis-polybutadiene and the melting point of the polyethylene, respectively. They are synthesized in the presence of a catalytic system comprising three components: rare-earth metallocene, borate, and hydride alkylaluminum. Due to the method used, the formation of each additional block requires the addition of a new monomer feed to the polymerization medium after the synthesis of the first block. Therefore, the synthesis of a triblock polymer requires three monomer feeds, the synthesis of a pentablock polymer requires five monomer feeds, and so on. However, those skilled in the art know that adding monomer feed to the polymerization medium during the polymerization reaction is often accompanied by the deactivation of certain active sites involved in the polymerization reaction, which has the effect of forming polymer species other than the target block polymer. This reduces the yield of the target block polymer. Summary of the Invention

[0003] The applicant has discovered a more efficient method for synthesizing ethylene and 1,3-diene-based multiblock polymers because it reduces the amount of monomer feed and thus increases the yield of the desired multiblock polymer.

[0004] Therefore, the first subject of this invention is a method for preparing a multiblock polymer, the method comprising statistical copolymerization of a monomer mixture comprising ethylene and 1,3-diene, followed by subsequent polymerization of ethylene in the presence of a catalytic system based on at least one metallocene of formula (Ia) or (Ib) and an organomagnesium reagent of formula (IIa) or (IIb).

[0005] {P(Cp 1 (Cp) 2 )Y} (Ia)

[0006] Cp 3 Cp4 Y (Ib)

[0007] Y represents a group containing rare earth metal atoms.

[0008] Cp 1 and Cp 2 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted.

[0009] P is a bridging group between two Cp groups. 1 and Cp 2 And contains groups containing silicon or carbon atoms,

[0010] Cp 3 and Cp 4 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted.

[0011] R B -(Mg-R A ) m -Mg-R B (IIa)

[0012] X-Mg-R A -Mg-X (IIb)

[0013] R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups.

[0014] R B It contains a benzene nucleus substituted with a magnesium atom, wherein one carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group, or forms a ring with the nearest carbon atom located meta-position of the magnesium atom, and another carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group.

[0015] X is a halogen atom.

[0016] m is a number greater than or equal to 1, preferably equal to 1.

[0017] The second subject of this invention is a multiblock polymer, particularly a triblock polymer, that can be obtained by the method according to the invention. Its key characteristic is that it contains divalent groups generated within the polymer chain by the method used to manufacture it. Its advantage lies in less contamination of polymer species due to partial deactivation of the active sites during polymerization. Detailed Implementation

[0018] Any numerical interval expressed as “between a and b” represents a range of values ​​greater than “a” and less than “b” (i.e., excluding the limits a and b), while any numerical interval expressed as “from a to b” means a range of values ​​extending from “a” to “b” (i.e., including the strict limits a and b).

[0019] The term "based on" used to define the components of a catalytic system or composition means a mixture of these components, or some or all of these components and the reaction products of each other.

[0020] Unless otherwise stated, the content of units resulting from the insertion of monomers into the polymer is expressed as a molar percentage relative to all monomer units constituting the polymer.

[0021] The compounds mentioned in the specification may be fossil-derived compounds or bio-based compounds. In the case of bio-based compounds, they may be partially or wholly derived from biomass or obtained from renewable starting materials derived from biomass. Similarly, the mentioned compounds may also be derived from the recycling of already used materials, i.e., they may be partially or wholly derived from recycling processes or obtained from raw materials that are themselves derived from recycling processes.

[0022] In a known manner, the ethylene unit is a unit having a -(CH2-CH2)- unit. It is also known that 1,3-dienes can be inserted into the growing polymer chain by 1,4-intercalation, 2,1-intercalation, or 3,4-intercalation (in the case of substituted dienes (e.g., isoprene)) to produce 1,4-configured, 1,2-configured, or 3,4-configured 1,3-diene units, respectively.

[0023] The method according to the invention comprises statistical copolymerization of a monomer mixture containing ethylene and 1,3-diene, followed by subsequent polymerization of ethylene.

[0024] In this patent application, the term "metallocene" refers to an organometallic complex in which the metal (in this case, a rare earth metal atom) is bonded to two groups Cp. 3 and Cp 4 Or bonded to two Cp groups 1 and Cp 2 The ligand molecule consists of the two groups Cp 1 and Cp 2 These groups are connected together via bridge P. 1 Cp 2 Cp 3 and Cp 4They can be the same or different and are selected from fluorenyl, cyclopentadienyl, and indene groups, which can be substituted or unsubstituted. To recall, rare earth elements are metals and represent the elements scandium, yttrium, and the lanthanides (with atomic numbers ranging from 57 to 71).

[0025] According to a first variant of the invention, the metallocene used as a basic component in the catalytic system corresponds to formula (Ia).

[0026] {P(Cp 1 (Cp) 2 )Y}(Ia)

[0027] in

[0028] Y represents a group containing rare earth metal atoms.

[0029] Cp 1 and Cp 2 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted.

[0030] P is a bridging group between two Cp groups. 1 and Cp 2 It contains groups that contain silicon or carbon atoms.

[0031] According to a second variant of the invention, the metallocene used as a basic component in the catalytic system according to the invention corresponds to formula (Ib).

[0032] Cp 3 Cp 4 Y(Ib)

[0033] in

[0034] Y represents a group containing rare earth metal atoms.

[0035] Cp 3 and Cp 4 The same or different, and selected from fluorenyl, cyclopentadienyl and indene groups, said groups being substituted or unsubstituted.

[0036] As substituted cyclopentadienyl, fluorenyl, and indole groups, references may be made to cyclopentadienyl, fluorenyl, and indole groups substituted with alkyl groups containing 1 to 6 carbon atoms, aryl groups containing 6 to 12 carbon atoms, or trialkylsilyl groups (e.g., SiMe3). The choice of groups also depends on the availability of the corresponding molecules (substituted cyclopentadiene, fluorenyl, and indole), as these molecules are commercially available or readily synthesized.

[0037] As substituted fluorenyl groups, those substituted at positions 2, 7, 3, or 6 can be mentioned, particularly 2,7-di(tert-butyl)fluorenyl and 3,6-di(tert-butyl)fluorenyl. Positions 2, 3, 6, and 7 represent the positions of carbon atoms in the ring shown in the diagram below, and position 9 corresponds to the carbon atom attached to bridge P.

[0038]

[0039] As a substituted cyclopentadienyl group, cyclopentadienyl groups substituted at positions 2 (or 5) and 3 (or 4) can be mentioned, especially cyclopentadienyl groups substituted at position 2, and even more particularly tetramethylcyclopentadienyl groups. As shown in the figure below, position 2 (or 5) indicates the position of the carbon atom adjacent to the carbon atom attached to bridge P.

[0040]

[0041] As substituted indenyl groups, those substituted at position 2 are particularly noteworthy, especially 2-methylindenyl or 2-phenylindenyl. As shown in the diagram below, position 2 indicates the position of the carbon atom adjacent to the carbon atom attached to bridge P.

[0042]

[0043] Preferably, the metallocene has formula (Ia).

[0044] Preferably, Cp 1 and Cp 2 The same, and selected from substituted fluorenyl groups and formula C 13 The unsubstituted fluorenyl group of H8. A special feature of the catalytic system according to this preferred embodiment is that it produces a copolymer based on butadiene and ethylene, which, in addition to the ethylene monomer unit and the butadiene unit, also comprises a cyclic unit having a 1,2-cyclohexanediyl unit of the following formula:

[0045]

[0046] Advantageously, Cp 1 and Cp 2 The same, and each representing the expression C denoted by the symbol Flu. 13 The unsubstituted fluorenyl group of H8.

[0047] Preferably, the symbol Y represents the group Met-G, where Met represents a rare earth metal atom, and G represents a group containing a borohydride unit BH4, or a halogen atom selected from chlorine, fluorine, bromine, and iodine. Advantageously, G represents a chlorine atom or a group of formula (III):

[0048] (BH4) (1+y) -Ly -N x (III)

[0049] in

[0050] L indicates an alkali metal selected from lithium, sodium, and potassium.

[0051] N represents an ether molecule.

[0052] x can be an integer or a non-integer, and is greater than or equal to 0.

[0053] y is an integer, and is greater than or equal to 0.

[0054] Very advantageously, G represents the group of formula (III).

[0055] Any ether that has the ability to coordinate with alkali metals (especially diethyl ether and tetrahydrofuran) is suitable as an ether.

[0056] The metal (rare earth metal) of the metallocene is preferably a lanthanide element (with an atomic number ranging from 57 to 71), and more preferably neodymium (Nd).

[0057] Linking group Cp 1 and Cp 2 The preferred bridge P corresponds to formula ZR. 1 R 2 Where Z represents a silicon atom or a carbon atom, R 1 and R 2 They may be the same or different, and each represents an alkyl group containing 1 to 20 carbon atoms, preferably methyl. In formula ZR 1 R 2 In this context, Z favorably represents the silicon atom Si.

[0058] Metallocenes used in the synthetic catalytic system can be in crystalline or amorphous powder form, or in single-crystal form. Metallocenes can be in monomeric or dimer form, depending on the method of preparation, as described, for example, in patent applications WO 2007 / 054224 or WO 2007 / 054223. Metallocenes can be conventionally prepared by methods similar to those described in patent applications WO 2007 / 054224 or WO 2007 / 054223, particularly under inert and anhydrous conditions by reacting an alkali metal salt of a ligand with a rare earth metal borohydride in a suitable solvent (e.g., an ether (e.g., 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 by techniques known to those skilled in the art (e.g., filtration or precipitation from a second solvent). Finally, the metallocene is dried and separated in solid form.

[0059] According to particularly preferred embodiments, metallocenes have formulas (III-1), (III-2), (III-3), (III-4), or (III-5):

[0060] [Me2Si(Flu)2Nd(μ-BH4)2Li(THF)] (III-1)

[0061] [{Me2SiFlu2Nd(μ-BH4)2Li(THF)}2] (III-2)

[0062] [Me2SiFlu2Nd(μ-BH4)(THF)] (III-3)

[0063] [{Me2SiFlu2Nd(μ-BH4)(THF)}2] (III-4)

[0064] [Me2SiFlu2Nd(μ-BH4)] (III-5)

[0065] Where Flu represents C 13 H8 group.

[0066] Another essential component of the catalytic system is a co-catalyst (an organomagnesium reagent of formula (IIa) or (IIb)).

[0067] R B -(Mg-R A ) m -Mg-R B (IIa)

[0068] X-Mg-R A -Mg-X (IIb)

[0069] R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups.

[0070] R B It contains a benzene nucleus substituted with a magnesium atom, wherein one carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group, or forms a ring with the nearest carbon atom located meta-position of the magnesium atom, and another carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group.

[0071] X is a halogen atom.

[0072] m is a number greater than or equal to 1, preferably equal to 1.

[0073] The cocatalysts of formulas (IIa) and (IIb) are characterized by containing two magnesium-carbon bonds involving different magnesium atoms. In formula (IIa), each of the two magnesium atoms is bonded to a different magnesium atom belonging to R. B The first carbon atom shares the first bond with the R atom. A The second carbon atom shares the second bond. The first carbon atom is R. B The second carbon atom is a component of the benzene ring. A The components of the aliphatic hydrocarbon chain R A It may contain one or more heteroatoms selected from oxygen and sulfur, or one or more aryl groups within its chain. In the preferred case where m equals 1, each magnesium atom is thereby associated with R. B The first carbon atom shares the first bond and is associated with R. A The second carbon atom shares the second bond. In formula (IIb), each magnesium atom thus shares the first bond with the halogen atom and with R. A The carbon atoms share the second bond.

[0074] In equation (IIa), R B Its characteristic lies in the presence of a benzene ring replaced by a magnesium atom. R B The benzene ring is located at the two carbon atoms adjacent to magnesium, which may have the same or different substituents. Alternatively, R B The benzene nucleus, located at one of the two carbon atoms adjacent to magnesium, can carry a substituent, and R B The benzene ring, located at the adjacent carbon atom of magnesium, can form a ring. The substituents are methyl, ethyl, or isopropyl. In R... B When one of the two carbon atoms adjacent to magnesium in the benzene ring is replaced by an isopropyl group, R B The second carbon atom of the benzene ring, located adjacent to magnesium, is preferably not substituted with an isopropyl group. Preferably, R... B The carbon atom of the benzene ring located adjacent to magnesium is replaced by a methyl or ethyl group. More preferably, R B The benzene ring, located at the position adjacent to the magnesium atom, is replaced by a methyl group.

[0075] The organomagnesium compound of formula (IIa) preferably corresponds to formula (IIa-m), wherein R1 and R5 are the same or different and represent methyl or ethyl, preferably methyl, R2, R3 and R4 are the same or different and represent hydrogen atoms or alkyl groups, R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups, and m is greater than or equal to 1. Preferably, R1 and R5 represent methyl groups. Preferably, R2 and R4 represent hydrogen atoms.

[0076]

[0077] Organomagnesium compounds of formula (IIa-m) have formula (IIa-1), in which m equals 1.

[0078]

[0079] According to preferred variants, in formula (IIa-m), particularly in formula (IIa-1), R1, R3, and R5 are identical. According to more preferred variants, R2 and R4 represent hydrogen, and R1, R3, and R5 are identical. In even more preferred variants, R2 and R4 represent hydrogen, and R1, R3, and R5 represent methyl groups.

[0080] In equations (IIa) and (IIa-m), and especially in equations (IIa-1) and (IIb), R A It is a divalent aliphatic hydrocarbon chain, which may contain one or more heteroatoms selected from oxygen or sulfur, or one or more aryl groups within its chain. Preferably, R A It is a branched or linear alkyldiyl, cycloalkyldiyl, or xylenediyl group. More preferably, R A It is an alkyl diol.

[0081] Preferably, R A It contains 3 to 10 carbon atoms, especially 3 to 8 carbon atoms.

[0082] Even more preferably, R A It is an alkyldiyl group containing 3 to 10 carbon atoms. Advantageously, R A It is an alkyldiyl group containing 3 to 8 carbon atoms. Very advantageously, R... A It is a linear alkyl diyl group. 1,3-propanediyl, 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl, 1,7-heptanediyl, and 1,8-nonanediyl are most particularly suitable as the R group. A .

[0083] According to any embodiment of the invention, in formula (IIa), particularly in formula (IIa-m), m is preferably equal to 1.

[0084] Organomagnesium compounds of formula (IIa) can be derived by including formula X'Mg-R A -MgX' first organomagnesium reagent with formula R B The second organomagnesium reagent, -Mg-X', is prepared by a reaction method, where X' represents a halogen atom, preferably bromine or chlorine, and R... B and R AAs defined above. X' is more preferably a bromine atom. The stoichiometry used in the reaction determines the value of m in formulas (IIa) and (IIa-m). For example, a molar ratio of 0.5 between the amount of the first organomagnesium reagent and the amount of the second organomagnesium reagent favors the formation of an organomagnesium compound of formula (IIa) with m equal to 1, while a molar ratio greater than 0.5 will favor the formation of an organomagnesium compound of formula (IV) with m greater than 1.

[0085] To carry out the reaction between the first and second organomagnesium reagents, a solution of the second organomagnesium reagent is typically added to a solution of the first organomagnesium reagent. The solutions of the first and second organomagnesium reagents are typically solutions of ethers (e.g., diethyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran) or mixtures of two or more of these ethers. Preferably, the concentrations of the first and second organomagnesium reagent solutions are 0.01 mol / L to 3 mol / L and 0.02 mol / L to 5 mol / L, respectively. More preferably, the concentrations of the first and second organomagnesium reagents are 0.1 mol / L to 2 mol / L and 0.2 mol / L to 4 mol / L, respectively.

[0086] The first and second organomagnesium reagents can be prepared in advance from magnesium metal and suitable precursors via a Grignard reaction. For both the first and second organomagnesium reagents, the respective precursors are of formula X'-R. A -X' and R B -X',R A R B X' is as defined above. The Grignard reaction is typically carried out by adding a precursor to magnesium metal, usually in fragment form. Preferably, iodine (I2), usually in bead form, is introduced into the reactor prior to the addition of the precursor, thereby activating the Grignard reaction in a known manner.

[0087] Alternatively, organomagnesium compounds of formula (IIa) can be derived via formula MR A -M organometallic compounds and formula R B The reaction preparation of -Mg-X' organomagnesium reagents, where M represents a lithium atom, sodium atom, or potassium atom, and X', R B and R A As defined above. Preferably, M represents a lithium atom, in which case the formula MR A -M organometallic compounds are organolithium reagents.

[0088] The reaction of organolithium reagents with organomagnesium reagents is typically carried out in ethers (e.g., diethyl ether, dibutyl ether, tetrahydrofuran, or methyltetrahydrofuran). The reaction is also typically conducted at temperatures ranging from 0°C to 60°C. Contact is preferably carried out at temperatures between 0°C and 23°C. Formula MR A-M organometallic compounds and formula R B Contact with organomagnesium reagents of -Mg-X' is preferably achieved by using organometallic compounds MR A -M solution added to organomagnesium reagent R B The reaction is carried out in a solution of -Mg-X'. Organometallic compounds MR A The solution of -M is usually a solution of a hydrocarbon solvent (preferably n-hexane, cyclohexane, or methylcyclohexane), and the organomagnesium reagent R B The solution of -Mg-X' is typically an ether solution (preferably diethyl ether or dibutyl ether). Preferably, the organometallic compound MR... A -M solution and organomagnesium reagent R B The concentrations of the -Mg-X' solutions were respectively from 0.01 mol / L to 1 mol / L and from 1 mol / L to 5 mol / L. More preferably, the organometallic compound MR A -M solution and organomagnesium reagent R B The concentrations of the -Mg-X' solutions were 0.05 mol / L to 0.2 mol / L and 2 mol / L to 3 mol / L, respectively.

[0089] As with any synthesis in the presence of organometallic compounds, the synthesis described for organomagnesium reagents is carried out under anhydrous conditions in an inert atmosphere in a stirred reactor. Typically, solvents and solutions are used under anhydrous nitrogen or argon atmospheres.

[0090] Following the formation of the organomagnesia reagent of formula (IIa), recovery is typically carried out in solution after filtration under an inert anhydrous atmosphere. Before use, the solution can be stored in a sealed container (e.g., a capped bottle) at a temperature between -25°C and 23°C.

[0091] Like any organomagnesia compound, the organomagnesia compound of formula (IIa) can be a monomer (R B -(Mg-R A ) m -Mg-R B )1 in form or polymer (R) B -(Mg-R A ) m -Mg-R B ) p The form (especially dimer (R) B -(Mg-R A ) m -Mg-R B)2), where p is an integer greater than 1, and m is as defined above. Furthermore, regardless of whether it is in monomeric or polymeric form, it can also be in the form of a substance coordinated to one or more solvent molecules (preferably ethers, such as diethyl ether, tetrahydrofuran, or methyltetrahydrofuran).

[0092] Compounds of formula (IIb) are well-known Grignard reagents. However, they have not yet been used as co-catalysts in catalytic systems for the preparation of polyolefins. Grignard reagents of formula (IIb) are described, for example, in J. March's book "Advanced Organic Chemistry" (4th edition, 1992, pp. 622-623) or Gary S. Silverman and Philip E. Rakita's book "Handbook of Grignard Reagents" (1996, pp. 502-503). They can be synthesized by reacting magnesium metal with formula XR C -X dihalogen compounds are synthesized by contacting R C As defined according to the present invention. For its synthesis, reference may be made to, for example, the volume "Organic Synthesis".

[0093] Like any organomagnesia compound, the organomagnesia reagent of formula (IIb) can be a monomer (X-Mg-R) A In the form of (-Mg-X)1 or polymeric substances (X-Mg-R) A -Mg-X) p (especially the dimer (X-Mg-R) A In the form of (-Mg-X)2), p is an integer greater than 1. Furthermore, regardless of whether it is in monomeric or polymeric form, it can also be in the form of a substance coordinated with one or more solvent molecules (preferably ethers, such as diethyl ether, tetrahydrofuran, or methyltetrahydrofuran). In formula (IIb), X is preferably a bromine atom or a chlorine atom, more preferably a bromine atom.

[0094] The catalytic system can be conventionally prepared by methods similar to those described in patent applications WO 2007 / 054224 or WO 2007 / 054223. For example, the cocatalyst (in this case, an organomagnesium reagent of formula (IIa) or (IIb)) and the metallocene are typically reacted in a hydrocarbon solvent at a temperature of 20°C to 80°C for a time between 5 and 60 minutes. The amounts of the cocatalyst and the metallocene reacted are such that the ratio between the molar number of Mg in the cocatalyst and the molar number of rare earth metals in the metallocene is preferably 1 to 200, more preferably 1 to less than 20. The numerical range of 1 to less than 20 is particularly advantageous for obtaining polymers with high molar masses. The catalytic system is typically prepared in an aliphatic hydrocarbon solvent (e.g., methylcyclohexane) or an aromatic hydrocarbon solvent (e.g., toluene). Typically, after synthesis, the catalytic system is used in methods for synthesizing polymers according to the invention.

[0095] Alternatively, the catalytic system can be prepared by a method similar to that described in patent application WO 2017 / 093654 A1 or patent application WO2018 / 020122 A1. According to this alternative, the catalytic system further comprises a pre-formed monomer selected from conjugated dienes, ethylene, or mixtures of ethylene and conjugated dienes. In this case, the catalytic system is at least based on metallocene, a cocatalyst, and the pre-formed monomer. For example, an organomagnesia reagent and a metallocene are typically reacted in a hydrocarbon-based solvent at a temperature of 20°C to 80°C for 10 to 20 minutes to obtain a first reaction product, followed by reaction of the pre-formed monomer selected from conjugated dienes, ethylene, or mixtures of ethylene and conjugated dienes with the first reaction product at a temperature of 40°C to 90°C for 1 to 12 hours. As a pre-formed monomer, the conjugated diene is preferably a 1,3-diene, such as 1,3-butadiene, isoprene, or a 1,3-diene of the formula CH2=CR-CH=CH2, where the symbol R represents a hydrocarbon chain containing 3 to 20 carbon atoms, particularly myrcene or β-farnesene. The resulting catalytic system can be used directly in the method for synthesizing the polymer according to the invention, or it can be stored in an inert atmosphere, particularly at temperatures from -20°C to room temperature (23°C), before being used for polymer synthesis.

[0096] As with any synthesis in the presence of organometallic compounds, the synthesis of metallocenes, organomagnesia reagents, and catalytic systems is carried out under anhydrous conditions in an inert atmosphere. Typically, the reaction begins with anhydrous solvents and compounds under anhydrous nitrogen or argon.

[0097] When a hydrocarbon solvent is present, the catalytic system can be in solution form. The hydrocarbon solvent can be an aliphatic solvent (e.g., methylcyclohexane) or an aromatic solvent (e.g., toluene). The hydrocarbon solvent is preferably an aliphatic solvent, more preferably methylcyclohexane. Typically, the catalytic system is stored in a hydrocarbon solvent as a solution prior to polymerization. This can then be referred to as a catalytic solution containing the catalytic system and the hydrocarbon solvent. The catalytic system preferably contains a hydrocarbon solvent. When the catalytic system is in solution, its concentration is defined by the amount of metallocene in the solution. The concentration of the metallocene is preferably from 0.0001 mol / L to 0.2 mol / L, more preferably from 0.001 mol / L to 0.03 mol / L.

[0098] Typically, a catalytic system is added to a reactor containing a polymerization solvent and monomer. To obtain the desired macroscopic structure of the multiblock polymer, those skilled in the art adjust the polymerization conditions, particularly the molar ratio of the organomagnesium reagent to the metal Nd constituting the metallocene. Molar ratios can reach values ​​up to 200, and it is known that molar ratios less than 20 are more favorable for obtaining polymers with high molar masses.

[0099] Those skilled in the art also adjust the polymerization conditions and the concentration of each reagent (component of the catalytic system, monomer) according to the equipment (tools, reactor) used to carry out the polymerization. Preferably, the monomer mixture comprising ethylene and 1,3-diene contains more than 50 mol% ethylene. As is known to those skilled in the art, the polymerization, as well as the operation of the monomers, catalytic system, and polymerization solvent, is carried out under anhydrous conditions in an inert atmosphere. The polymerization solvent is typically an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent.

[0100] The polymerization is preferably carried out continuously or discontinuously in solution, advantageously in a stirred reactor. The polymerization solvent can be an aromatic hydrocarbon solvent or an aliphatic hydrocarbon solvent. Examples of polymerization solvents that may be mentioned include toluene and methylcyclohexane. Advantageously, the polymerization is carried out in solution in a hydrocarbon solvent.

[0101] The preparation of multiblock polymers (also known as block polymers) involves the formation of ARs. AThe first block of -A (called the central block) subsequently forms other blocks (called successive blocks). The constituent monomer units of the successive blocks are incorporated into the growing polymer chain from each end of the central block. The formation of the central block requires a first monomer feed, in this case, a mixture of monomers comprising ethylene and 1,3-diene. The formation of successive blocks is achieved through polymerization reactions extending from different ends of the preceding block. Therefore, forming two blocks with the same microstructure from different ends of the preceding block requires a single monomer feed. Thus, in the synthesis of triblock polymers, two monomer feeds are used: a first monomer feed containing a mixture of ethylene and 1,3-diene for the synthesis of the central block, and a second monomer feed (in this case, polyethylene) for the synthesis of the terminal blocks.

[0102] According to the method of the present invention, B-(A) can be prepared by polymerization of continuously fed monomers (which are respectively a mixture containing ethylene and 1,3-diene and ethylene). 1 -B 1 ) n -AR A -A-(B 1 -A 1 ) n -B multiblock polymers, where A and A 1 Each represents a block that is a statistical copolymer comprising 1,3-diene units and ethylene units, B and B 1 Each represents such a block, wherein the block is polyethylene, n is an integer greater than or equal to 0, and R A The polymer chain is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups. The presence of divalent groups in the polymer chain arises from the co-catalyst used in the preparation of the multiblock polymer.

[0103] According to the present invention, the central block is a "statistical copolymer", which means that the constituent monomer units of the central block are statistically distributed in the central block because the monomers are statistically incorporated into the growing polymer chain.

[0104] In the preparation of the central block copolymer, the polymerization temperature typically varies within the range of 30°C to 160°C, preferably 30°C to 120°C. During the preparation of the central block copolymer, the temperature of the reaction medium in the copolymerization process is advantageously kept constant, and the total reaction pressure is also advantageously kept constant. The preparation of the central block is accomplished by cutting off the monomer supply, particularly by reducing the reactor pressure (preferably to about 3 bar).

[0105] The subsequent ethylene polymerization is continued by applying ethylene pressure to the reactor, which is kept constant, until the desired ethylene consumption is achieved, thereby obtaining the desired number-average molar mass of the polyethylene block. The applied ethylene polymerization temperature is preferably the same as that used for the preparation of the central block. The polymerization temperature used to prepare the polyethylene block typically varies from 30°C to 160°C, preferably from 30°C to 120°C. The pressure used to prepare the polyethylene block typically varies from 1 bar to 150 bar, preferably from 1 bar to 10 bar. The synthesis of the polyethylene block is complete when the desired number-average molar mass is reached.

[0106] In the case of preparing triblock polymers, polymerization is stopped. In the case of preparing multiblock polymers containing more than three blocks (e.g., pentablock), polymerization continues with subsequent polymerization via monomer feed. For continuous blocks containing ethylene and 1,3-diene units, the monomer feed consists of a mixture containing ethylene and 1,3-diene, and polymerization is carried out under temperature and pressure conditions similar to those for the preparation of central blocks. For continuous polyethylene blocks, the monomer feed consists of ethylene, and polymerization is carried out under the pressure and temperature conditions already described for the synthesis of polyethylene blocks. Polymerization is stopped at the end of the multiblock polymer synthesis.

[0107] Polymerization can be terminated by cooling the polymerization medium or by adding an alcohol (preferably an alcohol containing 1 to 3 carbon atoms, such as ethanol). Multiblock polymers, especially triblock polymers, can be recovered using conventional techniques known to those skilled in the art (e.g., precipitation, solvent evaporation under reduced pressure, or steam stripping).

[0108] In the method according to the invention, the 1,3-diene in the mixture comprising ethylene and 1,3-diene can be a 1,3-diene containing 4 to 20 carbon atoms. The 1,3-diene is preferably a mixture of 1,3-dienes (one of which is 1,3-butadiene) or 1,3-butadiene and isoprene. More preferably, the 1,3-diene is 1,3-butadiene according to any embodiment of the invention.

[0109] According to a particularly preferred embodiment of the invention, the monomer mixture comprising ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene, which is equivalent to saying that ethylene and 1,3-diene are the only monomers in the monomer mixture. Advantageously, the monomer mixture comprising ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene, and contains more than 50 mol% ethylene.

[0110] According to another particularly preferred embodiment of the invention, the method is capable of synthesizing a triblock polymer of the formula BAB, wherein A (referred to as the central block) is a statistical copolymer comprising 1,3-diene units and ethylene units, and B (referred to as the terminal block) is polyethylene. Advantageously, the central block A is a statistical copolymer comprising 1,3-diene units and more than 50 mol% of ethylene units. Very advantageously, the central block A is a statistical copolymer of ethylene and 1,3-diene comprising more than 50 mol% of ethylene units. In this patent application, the content of ethylene units in the central block (i.e., the number of moles of ethylene units in the central block) is expressed as a mole percentage relative to the number of moles of the monomer units constituting the central block.

[0111] Preferably, the method is capable of synthesizing block polymers, wherein the block polymers are elastomers.

[0112] The polymer according to the invention (which is another subject of the invention) can be prepared by a specific embodiment of the method according to the invention, wherein R A Not an ethylene unit, a 1,3-diene unit, an ethylene unit chain, a 1,3-diene unit chain, or a chain of units composed of one or more ethylene units and one or more 1,3-diene units. The polymer according to the invention is a multiblock polymer of formula (IV).

[0113] B-(A 1 -B 1 ) n -AR A -A-(B 1 -A 1 ) n -B(IV)

[0114] Among them A and A 1 Each represents a block that is a statistical copolymer comprising 1,3-diene units and ethylene units, B and B 1 Each represents such a block, wherein the block is polyethylene, n is an integer greater than or equal to 0, and R A It is an aliphatic hydrocarbon divalent chain, said aliphatic hydrocarbon divalent chain is interrupted or not interrupted by one or more oxygen atoms or sulfur atoms or one or more aryl groups, and R A It is not an ethylene unit, a 1,3-diene unit, an ethylene unit chain, a 1,3-diene unit chain, or a chain of units consisting of one or more ethylene units and one or more 1,3-diene units.

[0115] Preferably, the polymer according to the invention is an elastomer.

[0116] According to a particularly preferred embodiment of the invention, the multiblock polymer is a polymer of formula (IV), where n equals 0. In this case, the polymer is triblock, preferably an elastomer.

[0117] According to another embodiment of the invention (which may be combined with other embodiments related to the polymer according to the invention), the multiblock polymer comprises 1,2-cyclohexanediyl units.

[0118] In summary, the present invention is advantageously carried out according to any one of the following embodiments 1 to 40:

[0119] Implementation Scheme 1: A method for preparing a multiblock polymer, the method comprising statistical copolymerization of a monomer mixture comprising ethylene and 1,3-diene, followed by subsequent polymerization of ethylene in the presence of a catalytic system based on at least one metallocene of formula (Ia) or (Ib) and an organomagnesium reagent of formula (IIa) or (IIb).

[0120] {P(Cp 1 (Cp) 2 )Y} (Ia)

[0121] Cp 3 Cp 4 Y (Ib)

[0122] Y represents a group containing rare earth metal atoms.

[0123] Cp 1 and Cp 2 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted.

[0124] P is a bridging group between two Cp groups. 1 and Cp 2 And contains groups containing silicon or carbon atoms,

[0125] Cp 3 and Cp 4 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted.

[0126] R B -(Mg-R A ) m -Mg-R B (IIa)

[0127] X-Mg-R A -Mg-X (IIb)

[0128] R AIt is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups.

[0129] R B It contains a benzene nucleus substituted with a magnesium atom, wherein one carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group, or forms a ring with the nearest carbon atom located meta-position of the magnesium atom, and another carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group.

[0130] X is a halogen atom.

[0131] m is a number greater than or equal to 1, preferably equal to 1.

[0132] Implementation Scheme 2: According to the method of Implementation Scheme 1, wherein the symbol Y represents the group Met-G, where Met represents a rare earth metal atom, and G represents a halogen atom selected from chlorine, fluorine, bromine and iodine or a group containing a borohydride unit BH4.

[0133] Implementation Scheme 3: The method according to Implementation Scheme 2, wherein G represents a chlorine atom or a group of formula (III).

[0134] (BH4) (1+y) -L y -N x (III)

[0135] in

[0136] L indicates an alkali metal selected from lithium, sodium, and potassium.

[0137] N represents an ether molecule, preferably diethyl ether or tetrahydrofuran.

[0138] x can be an integer or a non-integer, and is greater than or equal to 0.

[0139] y is an integer, and is greater than or equal to 0.

[0140] Implementation Scheme 4: The method according to Implementation Scheme 3, wherein G represents the group of formula (III).

[0141] Implementation Scheme 5: The method described in any one of Implementation Schemes 1 to 4, wherein the rare earth metal is a lanthanide element with an atomic number ranging from 57 to 71.

[0142] Implementation Scheme 6: The method described in any one of Implementation Schemes 1 to 5, wherein the rare earth metal is neodymium.

[0143] Implementation Scheme 7: The method according to any one of Implementation Schemes 1 to 6, wherein the metallocene has formula (Ia).

[0144] Implementation Scheme 8: The method described according to any one of Implementation Schemes 1 to 7, wherein Cp 1 and Cp 2 The same, and selected from substituted fluorenyl groups and formula C 13 The unsubstituted fluorenyl group of H8.

[0145] Implementation Scheme 9: The method described according to any one of Implementation Schemes 1 to 8, wherein Cp 1 and Cp 2 Same, and for formula C 13 The fluorene group of H8.

[0146] Implementation Scheme 10: The method according to any one of Implementation Schemes 1 to 9, wherein bridge P corresponds to formula ZR. 1 R 2 Z represents silicon or carbon atoms, R 1 and R 2 They may be the same or different, and each represents an alkyl group containing 1 to 20 carbon atoms.

[0147] Implementation Scheme 11: The method according to Implementation Scheme 10, wherein R 1 and R 2 They can be the same or different, and each can represent a methyl group.

[0148] Implementation Scheme 12: The method according to Implementation Scheme 10 or 11, wherein Z represents a silicon atom.

[0149] Implementation Scheme 13: The method according to any one of Implementation Schemes 1 to 12, wherein the metallocene has formula (III-1), (III-2), (III-3), (III-4), or (III-5):

[0150] [Me2Si(Flu)2Nd(μ-BH4)2Li(THF)] (III-1)

[0151] [{Me2SiFlu2Nd(μ-BH4)2Li(THF)}2] (III-2)

[0152] [Me2SiFlu2Nd(μ-BH4)(THF)] (III-3)

[0153] [{Me2SiFlu2Nd(μ-BH4)(THF)}2] (III-4)

[0154] [Me2SiFlu2Nd(μ-BH4)] (III-5)

[0155] Flu represents C 13 H8 group.

[0156] Implementation Scheme 14: The method according to any one of Implementation Schemes 1 to 13, wherein if R B If one of the two carbon atoms adjacent to magnesium in the benzene ring is replaced by an isopropyl group, then R B The second carbon atom of the benzene ring, located adjacent to magnesium, is not replaced by an isopropyl group.

[0157] Implementation Scheme 15: The method according to any one of Implementation Schemes 1 to 14, wherein R B The carbon atom in the benzene ring located adjacent to magnesium is replaced by a methyl or ethyl group.

[0158] Implementation Scheme 16: The method according to any one of Implementation Schemes 1 to 15, wherein R B The benzene ring, located at the position adjacent to the magnesium atom, is replaced by a methyl group.

[0159] Implementation Scheme 17: The method according to any one of Implementation Schemes 1 to 16, wherein the organomagnesium reagent of formula (IIa) has formula (IIa-m),

[0160]

[0161] R1 and R5 may be the same or different, and represent methyl or ethyl, preferably methyl.

[0162] R2, R3, and R4 may be the same or different, and may be either hydrogen atoms or alkyl groups.

[0163] R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups.

[0164] m is a number greater than or equal to 1, preferably equal to 1.

[0165] Implementation Scheme 18: The method described in any one of Implementation Schemes 1 to 17, wherein m equals 1.

[0166] Implementation Scheme 19: The method according to Implementation Scheme 17 or 18, wherein R1 and R5 represent methyl groups.

[0167] Implementation Scheme 20: The method according to any one of Implementation Schemes 17 to 19, wherein R2 and R4 represent hydrogen atoms.

[0168] Implementation Scheme 21: The method according to any one of Implementation Schemes 1 to 20, wherein R A It is a branched or linear alkyldiyl, cycloalkyldiyl, or xylenediyl group.

[0169] Implementation Scheme 22: The method according to any one of Implementation Schemes 1 to 21, wherein R AIt is an alkyl diol.

[0170] Implementation Scheme 23: The method according to any one of Implementation Schemes 1 to 22, wherein R A It contains 3 to 10 carbon atoms.

[0171] Implementation Scheme 24: The method according to any one of Implementation Schemes 1 to 23, wherein R A It contains 3 to 8 carbon atoms.

[0172] Implementation Scheme 25: The method according to any one of Implementation Schemes 1 to 24, wherein X is a bromine atom or a chlorine atom.

[0173] Implementation Scheme 26: The method described according to any one of Implementation Schemes 1 to 25, wherein X is a bromine atom.

[0174] Implementation Scheme 27: The method according to any one of Implementation Schemes 1 to 26, wherein the monomer mixture comprising ethylene and 1,3-diene comprises more than 50 mol% ethylene.

[0175] Implementation Scheme 28: The method according to any one of Implementation Schemes 1 to 27, wherein the monomer mixture comprising ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene.

[0176] Implementation Scheme 29: The method according to any one of Implementation Schemes 1 to 28, wherein the 1,3-diene is a mixture of 1,3-dienes or 1,3-butadiene and isoprene, and one of the mixtures of 1,3-dienes is 1,3-butadiene.

[0177] Implementation Scheme 30: The method according to any one of Implementation Schemes 1 to 29, wherein the 1,3-diene is 1,3-butadiene.

[0178] Implementation Scheme 31: The method according to any one of Implementation Schemes 1 to 30, wherein the multiblock polymer comprises a 1,2-cyclohexanediyl unit.

[0179] Implementation Scheme 32: The method according to any one of Implementation Schemes 1 to 31, wherein the multiblock polymer is a triblock polymer of formula BAB, wherein A is called the central block and is a statistical copolymer comprising 1,3-diene units and ethylene units, and B is called the terminal block and is polyethylene.

[0180] Implementation Scheme 33: The method according to any one of Implementation Schemes 1 to 32, wherein the multiblock polymer is an elastomer.

[0181] Implementation Scheme 34: Multiblock Polymer of Formula (IV)

[0182] B-(A1 -B 1 ) n -AR A -A-(B 1 -A 1 ) n -B(IV)

[0183] Among them A and A 1 Each represents a block that is a statistical copolymer comprising 1,3-diene units and ethylene units, B and B 1 Each represents such a block, wherein the block is polyethylene, n is an integer greater than or equal to 0, and R A It is an aliphatic hydrocarbon divalent chain, said aliphatic hydrocarbon divalent chain is interrupted or not interrupted by one or more oxygen atoms or sulfur atoms or one or more aryl groups, and R A It is not an ethylene unit, a 1,3-diene unit, an ethylene unit chain, a 1,3-diene unit chain, or a chain of units consisting of one or more ethylene units and one or more 1,3-diene units.

[0184] Implementation Scheme 35: The polymer according to Implementation Scheme 34, wherein the polymer is an elastomer.

[0185] Implementation Scheme 36: The polymer according to Implementation Scheme 34 or 35, wherein the polymer is a triblock of formula (IV), where n equals 0.

[0186] Implementation Scheme 37: The polymer according to any one of Implementation Schemes 34 to 36, wherein the 1,3-diene is a mixture of 1,3-dienes or 1,3-butadiene and isoprene, and one of the mixtures of 1,3-dienes is 1,3-butadiene.

[0187] Implementation Scheme 38: The polymer according to any one of Implementation Schemes 34 to 37, wherein the polymer comprises a 1,2-cyclohexanediol unit.

[0188] Implementation Scheme 39: The method according to any one of Implementation Schemes 1 to 33, wherein the ratio between the molar number of Mg in the co-catalyst and the molar number of rare earth metals in the metallocene ranges from 1 to 200.

[0189] Implementation Scheme 40: The method according to any one of Implementation Schemes 1 to 33, wherein the ratio between the molar number of Mg in the co-catalyst and the molar number of rare earth metals in the metallocene ranges from 1 to less than 20.

[0190] The above and other features of the invention will become clearer from the following description of several embodiments of the invention given as a non-limiting description.

[0191] Example:

[0192] High-Temperature Size Exclusion Chromatography (HT-SEC). Analysis was performed using a Viscotek (Malvern Instruments) system equipped with three columns (PLgel Olexis 300mm × 7mm ID from Agilent Technologies) and three detectors (differential refractometer, viscometer, and light scattering). 1 mL min was used in 1,2,4-trichlorobenzene at 150 °C. -1 The flow rate was 200 μL for a concentration of 3 mg / mL. -1 The sample solution was prepared using 2,6-bis(tert-butyl)-4-cresol (400 mg / L). -1 A stable mobile phase was used. OmniSEC software was employed for data acquisition and analysis. A refractometer and viscometer were used with standard polystyrene (peak molar mass M) from the Polymer Standard Service (Mainz). p : 672 to 12,000,000 g mol -1 The number-average molar mass (Mn) of the synthesized ethylene-butadiene copolymer was calculated using a universal calibration curve.

[0193] Nuclear magnetic resonance (NMR). High-resolution analysis of the copolymer was performed on a Brüker 400 Avance III spectrometer equipped with a 5 mm BBFO probe and operating at 400 MHz. 1 ¹H NMR spectroscopy. Data was collected at 363 K. A mixture of tetrachloroethylene (TCE) and deuterated benzene (C6D6) (2 / 1 volume / volume) was used as the solvent. The concentration was 17 g L / L. -1 The sample was analyzed at a concentration of [value missing]. Chemical shifts are given in ppm relative to the deuterated benzene proton signal set at 7.16 ppm. The number of samples was set to 512.

[0194] Differential scanning calorimetry (DSC). A dynamic method including nine temperature stages is used in DSC 3. + Analysis was performed on the machine (Mettler Toledo): Phase 1: 20°C to 180°C (10°C min) -1 Phase 2: Isothermal at 180℃ (5 min); Phase 3: 180℃ to -80℃ (-10℃ min). -1 Phase 4: Isothermal -80℃ (5 min), Phase 5: -80℃ to 180℃ (10℃ min) -1 Stage 6: Isothermal at 180℃ (5 min); Stage 7: 180℃ to -80℃ (10℃ min) -1Stage 8: Isothermal -80℃ (5 min), Stage 9: -80℃ to 180℃ (10℃ min) -1 The first two heating cycles eliminate the thermal experience of the sample. The glass transition temperature and melting point are measured in stage nine. Stage seven is also maintained to obtain information related to the crystallinity of the sample. (Δ) This is relative to 100% crystallized polyethylene. f H = 293 J g -1 (B. Wunderlich, Thermal Analysis, Academic Press, 1990, p. 281) Determination of crystallinity.

[0195] Preparation of the co-catalyst 1,5-bis(magnesium bromide)pentanediyl (DBMP):

[0196] Magnesium (1.25 g, 50 mmol, 10 equivalents) was inertized in a 50 mL flask fitted with magnetized olivine and a 10 mL dropping funnel. Diiodine beads (10 mg) were added to the magnesium. 11 mL of MeTHF distilled over sodium / benzophenone was added to the flask with stirring, and 9 mL was added to the dropping funnel. 0.68 mL of 1,5-dibromopentane (5 mmol, 1 equivalent), degassed and dried using activated molecular sieves, was added to the dropping funnel. The haloalkane solution was poured dropwise onto the magnesium over 1 h. Stirring was maintained at 20 °C for 12 h. The solution was concentrated under vacuum and then diluted in 10 mL of toluene. The concentration of the pentanediyl group was estimated to be 0.45 mol / L. -1 .

[0197] 1 H NMR (C6D6-400 MHz-298 K) δ: ppm=2.06(quin, J=7.6Hz, “b”), 1.80(quin, J=7.4Hz, “c”), -0.05(t, J=7.7Hz, “a”); quin indicates a quintet.

[0198]

[0199] Preparation of a triblock polymer according to the present invention having a central block of ethylene and 1,3-butadiene and a terminal block of polyethylene:

[0200] 200 mL of toluene (Biosolve) purified on an SPS800 MBraun system was placed into an inert 250 mL flask containing magnetized olivine. While stirring, 0.6 mL (0.25 mmol) of the prepared 1,5-bis(magnesium bromide)pentanediyl (DBMP 0.45 mol / L) solution was added. -1A solution of ) was added to the flask. Then 16 mg (25 μmol) of {(Me₂Si(C)} was added. 13 H8)2)Nd(-BH4)[(-BH4)Li(THF)]}2 was added to the flask.

[0201] Preparation of the central block (Step 1): The catalytic system was then transferred to a 250 mL reactor via a sleeve at 70 °C under an inert atmosphere. The argon overpressure in the reactor was reduced to 0.5 bar, and then the reactor was pressurized to 4 bar with an ethylene / butadiene mixture at a molar ratio of 80 / 20 under stirring at 1000 rpm. The pressure in the reactor was kept constant through a tank containing the ethylene / butadiene mixture. After the pressure drop in the tank equaled approximately 13 g of monomer, the feed was stopped and the reactor was isolated until the pressure in the reactor reached 2.8 bar, thus obtaining 15 g of copolymer.

[0202] Preparation of the terminal block (step 2): The reactor was pressurized to 4 bar again using a tank containing only ethylene, and then about 3 g of monomer was consumed through the pressure drop in the tank.

[0203] The reactor was degassed, and the temperature was lowered to 20°C. The polymer solution was precipitated from methanol under stirring in the presence of approximately 20 mg of 2,2'-methylenebis(6-tert-butyl-4-cresol) as an antioxidant. The obtained polymer was dried under vacuum at 70°C for 4 h. 18.5 g of the dried triblock polymer was recovered. The characteristics of the triblock polymer are as follows:

[0204] Glass transition temperature Tg: -35℃, corresponding to the statistical copolymer block of ethylene and 1,3-butadiene;

[0205] Melting point Tm: 122℃, corresponding to polyethylene block;

[0206] Crystallinity: 8.9% by mass;

[0207] Mn HT-SEC: 62600g / mol.

[0208] The contents of ethylene units, 1,2-configured 1,3-butadiene units (1,2-units), 1,4-configured 1,3-butadiene units (1,4-units), and 1,2-cyclohexanediyl units (expressed as molar percentages relative to all monomer units of the polymer) were 81.9%, 6.7%, 4.0%, and 7.4%, respectively.

Claims

1. A method for preparing a multiblock polymer, the method comprising statistical copolymerization of a monomer mixture comprising ethylene and 1,3-diene, followed by subsequent polymerization of ethylene in the presence of a catalytic system based on at least one metallocene of formula (Ia) or (Ib) and an organomagnesium reagent of formula (IIa) or (IIb). {P(Cp 1 )(Cp 2 )Y}(Ia) Cp 3 Cp 4 Y(Ib) Y represents a group containing rare earth metal atoms. Cp 1 and Cp 2 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted. P is a bridging group between two Cp groups. 1 and Cp 2 And contains groups containing silicon or carbon atoms, Cp 3 and Cp 4 The groups may be the same or different, and are selected from fluorenyl, cyclopentadienyl, and indene groups, wherein the groups are substituted or unsubstituted. R B -(Mg-R A ) m -Mg-R B (IIa) X-Mg-R A -Mg-X(IIb) R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms or sulfur atoms or one or more aryl groups. R B It contains a benzene nucleus substituted with a magnesium atom, wherein one carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group, or forms a ring with the nearest carbon atom located meta-position of the magnesium atom, and another carbon atom of the benzene nucleus located adjacent to the magnesium atom is substituted with a methyl, ethyl, or isopropyl group. X is a halogen atom. m is a number greater than or equal to 1.

2. The method according to claim 1, wherein, The symbol Y represents the group Met-G, where Met represents a rare earth metal atom and G represents a halogen atom selected from chlorine, fluorine, bromine and iodine or a group containing the borohydride unit BH4.

3. The method according to claim 1 or 2, wherein, Rare earth metals are lanthanide elements, with atomic numbers ranging from 57 to 71.

4. The method according to claim 1, wherein, Bridge P corresponds to equation ZR 1 R 2 Z represents silicon or carbon atoms, R 1 and R 2 They may be the same or different, and each represents an alkyl group containing 1 to 20 carbon atoms.

5. The method according to claim 1, wherein, Metallocenes have formulas (III-1), (III-2), (III-3), (III-4), or (III-5): [Me2Si(Flu)2Nd(μ-BH4)2Li(THF)](III-1) [{Me2SiFlu2Nd(μ-BH4)2Li(THF)}2](III-2) [Me2SiFlu2Nd(μ-BH4)(THF)](III-3) [{Me2SiFlu2Nd(μ-BH4)(THF)}2](III-4) [Me2SiFlu2Nd(μ-BH4)](III-5) Flu represents C 13 H8 group.

6. The method according to claim 1, wherein, If R B If one of the two carbon atoms adjacent to magnesium in the benzene ring is replaced by an isopropyl group, then R B The second carbon atom of the benzene ring, located adjacent to magnesium, is not replaced by an isopropyl group.

7. The method according to claim 1, wherein, R B The carbon atom in the benzene ring located adjacent to magnesium is replaced by a methyl or ethyl group.

8. The method according to claim 1, wherein, Organomagnetic reagents of formula (IIa) have formula (IIa-m). R1 and R5 may be the same or different, and represent methyl or ethyl. R2, R3, and R4 may be the same or different, and may be either hydrogen atoms or alkyl groups. R A It is a divalent aliphatic hydrocarbon chain, which may or may not be interrupted by one or more oxygen atoms, sulfur atoms, or one or more aryl groups. m is a number greater than or equal to 1.

9. The method according to claim 1, wherein, R A It is a branched or linear alkyldiyl, cycloalkyldiyl, or xylenediyl group.

10. The method according to claim 1, wherein, R A It contains 3 to 10 carbon atoms.

11. The method according to claim 1, wherein, X is a bromine atom or a chlorine atom.

12. The method according to claim 1, wherein, The 1,3-diene is a mixture of 1,3-dienes or 1,3-butadiene and isoprene, wherein one of the mixtures of 1,3-dienes is 1,3-butadiene.

13. The method according to claim 1, wherein, The monomer mixture containing ethylene and 1,3-diene is a mixture of ethylene and 1,3-diene.

14. The method according to claim 1, wherein, The block polymer is a triblock polymer of formula BAB, wherein A is called the central block and is a statistical copolymer containing 1,3-diene units and ethylene units, and B is called the terminal block and is polyethylene.

15. Multiblock polymers of formula (IV) B-(A 1 -B 1 ) n -A-R A -A-(B 1 -A 1 ) n -B(IV) Among them A and A 1 Each represents a block that is a statistical copolymer comprising 1,3-diene units and ethylene units, B and B 1 Each represents such a block, wherein the block is polyethylene, n is an integer greater than or equal to 0, and R A It is an aliphatic hydrocarbon divalent chain, said aliphatic hydrocarbon divalent chain is interrupted or not interrupted by one or more oxygen atoms or sulfur atoms or one or more aryl groups, and R A It is not an ethylene unit, a 1,3-diene unit, an ethylene unit chain, a 1,3-diene unit chain, or a chain of units consisting of one or more ethylene units and one or more 1,3-diene units.

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