Diene rubbers made with unsaturated siloxane coupling agents

Abstract

A method for making a polydiene rubber comprising the steps of (i) polymerizing at least one aliphatic conjugated diene monomer, preferably having from 4 to 25 carbon atoms, to produce a polymer having reactive polymer chain ends, and (ii) reacting at least a portion of the reactive polymer chain ends with a coupling agent comprising from 2 to 20 unsaturated siloxane units, preferably from 3 to 15 unsaturated siloxane units, more preferably from 3 to 10 unsaturated siloxane units. Also provided are polydiene rubbers obtained by the method, curable compositions comprising the polydiene rubber, and compositions comprising the cured polydiene rubber.

Description

[Technical field]

[0001] This invention relates to diene rubbers made with unsaturated siloxane coupling agents. [Background technology]

[0002] Diene rubber is widely used as a raw material for manufacturing tires. Coupling agents can be used to improve the processability of diene rubber. Coupling agents link the polymer chains of rubber together to form branched or star-shaped polymer structures. This broadens the molecular weight distribution of the polymers, reduces the Mooney viscosity of compounds containing them, and makes them easier to process. Examples of known coupling reactants include silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, tin tetrachloride, dibutyltin dichloride, tetraalkoxysilane, derivatives of ethylene glycol diglycidyl ether, and 1,2,4-tris(chloromethyl)benzene. (Patent Document 1) reports the use of substituted silsesquioxanes and polycyclic substituted polysiloxanes as coupling agents. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2005 / 0107541A1 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a need to provide alternative coupling agents for coupling diene rubbers. [Means for solving the problem]

[0005] Thus, in one aspect, there is provided a method for producing a polydiene rubber, comprising the steps of: (i) polymerizing at least one aliphatic conjugated diene monomer to produce a polymer having a reactive polymer chain end; (ii) reacting at least a portion of the reactive polymer chain ends with a coupling agent comprising 2 to 20 unsaturated siloxane units, wherein the coupling agent comprises a cyclic structure having at least two unsaturated siloxane units, but the coupling agent is not polycyclic.

[0006] In another aspect, there is provided a polydiene rubber obtained by the above process.

[0007] In a further aspect, there is further provided a curable composition comprising the polydiene rubber described above, and further comprising at least one vulcanizing agent for curing the polydiene rubber.

[0008] In yet another aspect, there is provided a composition comprising a cured polydiene rubber obtained by curing the above-described curable composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present disclosure is further explained in the detailed description that follows.

[0010] In the following description, certain standards (ASTM, DIN, ISO, etc.) may be mentioned. Unless otherwise indicated, these standards are used in the version that was valid on March 1, 2020. If there is no version valid on that date, for example if the standard has expired, the version that was valid on the date closest to March 1, 2020 is mentioned.

[0011] All documents mentioned in this description are incorporated herein by reference unless otherwise stated.

[0012] In the following description, the amounts of components of a composition or polymer can be interchangeably referred to as "weight percent," "wt.%," or "% by weight." The terms "weight percent," "wt.%," or "% by weight" are based on the total weight of the composition or polymer, respectively, which is 100%, unless otherwise specified.

[0013] The term "phr" means "parts per hundred rubber", i.e., the weight percentage values ​​of components of a composition that include one or more rubbers are based on the total amount of rubber, which is set at 100% by weight. Thus, the total weight of the composition will usually be greater than the amount of rubber and may exceed 100% by weight.

[0014] Unless otherwise stated, ranges specified in this disclosure are meant to include and disclose all values ​​between the endpoints of the range, and those endpoints.

[0015] The term "comprising" is used in an open and non-limiting sense. The phrase "a composition comprising components A and B" means that the composition contains components A and B, but the composition may contain other components. In contrast to the use of "comprising", the word "consisting only of" is used in a narrow and limiting sense. The phrase "a composition consisting only of components A and B" is meant to describe a composition of components A and B without other components.

[0016] Siloxane coupling agent The coupling agents according to the present disclosure contain at least two unsaturated siloxane units, preferably at least 2-20, more preferably 3-15, and most preferably 4-10 unsaturated siloxane units. Thus, in addition to the -Si-O- units, the coupling agents according to the present disclosure contain at least two, preferably at least three, more preferably at least four units having at least one carbon-carbon double bond, preferably a vinyl group (-CH=CH2 group). Typically, these units are bonded to the silicon atom of the Si-O- units. Thus, these units are referred to herein as "unsaturated siloxane units" or "unsaturated -Si-O units". The coupling agents may be linear or branched or cyclic, but not polycyclic. Preferably, they are cyclic, preferably they contain at least one cyclic structure, preferably they have a cyclic siloxane structure, i.e. they have a cyclic structure with at least one unsaturated -Si-O- unit as described above. Preferably, the siloxane-based coupling agent is cyclic and has a cyclic structure having at least two unsaturated siloxane units, more preferably at least three unsaturated siloxane units.

[0017] The coupling agents according to the present disclosure are preferably used to couple polydiene rubbers, i.e. to bond polymer chains to each other, preferably to form branched, e.g. multi-arm or star-shaped, polymer structures. The coupling of the polymers can be confirmed by an increase in molecular weight, measured for example by GPC. The degree of coupling can be determined by comparing the chromatogram of the coupled polymer with that of its precursor polymer. If coupled, a high molecular weight fraction will appear in the chromatogram. The ratio of the integral of the coupled fraction to the integral of the total molecular weight distribution is the degree of coupling (mass % of polymer that is coupled).

[0018] The advantage of using the coupling agent according to the present disclosure in the manufacture of polydiene rubber is that it allows fine tuning of the polymer structure. When the siloxane-based reactants are used in molar excess of their unsaturated units relative to the polymer chain, the coupled polymer may contain unreacted unsaturated units from the coupling agent that can participate in crosslinking (vulcanization) reactions. However, if the presence of unsaturated groups from the coupling agent in the polymer is undesirable, their presence can be avoided or reduced by using the coupling agent in equimolar or less than equimolar amounts (based on the molar ratio of unsaturated units of the coupling agent to the polymer chain). In this case, it can be assumed that all the unsaturated units of the coupling reactant are used by the coupling reaction. It can be assumed that the molar amount of reactive polymer chains produced during the polymerization reaction is equal to the molar amount of polymerization initiator used during the polymerization reaction.

[0019] Coupling agents according to the present disclosure have the general formula (1): [ka] The compound contains 2 to 20 unsaturated siloxane units corresponding to the above formula (1), preferably 3 to 15 unsaturated siloxane units, and more preferably 4 to 10 unsaturated siloxane units.

[0020] In formula (1), each R1 independently represents an alkenyl group, preferably an alkenyl group selected from the group consisting of vinyl (-CH=CH2), allyl (-CH-CH2-CH=CH2), n-propenyl (-CH2CH=CH2), n-butenyl (-CH2CH2CH=CH2), isobutenyl (-CH2(CH3)CH=CH2); n-pentenyl (-CH2CH2CH2CH=CH2), isopentenyl (-CH2(CH3)CH2CH=CH2, -CH2CH2(CH3)CH=CH2), and each R2 independently represents H, OH, or an organic group, preferably having 1 to 20 carbon atoms, and optionally further having one heteroatom selected from O, S, Si, N, and combinations thereof. The hydrocarbon group may be unsubstituted or substituted, in which case at least one hydrogen atom is replaced by a substituent. Suitable substituents include siloxane, polysiloxane, silyl, aminosilyl, aminosiloxane, alkylamino group, halogen, and combinations thereof. Preferably, the hydrocarbon group is aliphatic. Preferably, the hydrocarbon group is selected from alkenyl, preferably alkenyl having 2 to 10 carbon atoms, alkyl, preferably alkyl having 1 to 10 carbon atoms, where the alkyl or alkenyl chain or both may be interrupted once or more than once by an ether oxygen atom, or R2 is selected from siloxanes or polysiloxanes having up to 10 silicon atoms, where the siloxane or polysiloxane may have at least one silicon atom optionally carrying at least one aliphatic substituent selected from an alkyl group, an alkylene group, or an alkenyl group, or combinations thereof. Preferably, at least one R2 represents methyl or ethyl. Preferably, all R2 represent methyl or ethyl or a combination thereof.

[0021] In one preferred embodiment of the present disclosure, the siloxane coupling agent has the general formula (2): [ka] wherein R corresponds to R2 in formula (1) above. Preferably, R is selected from an alkyl having 1-10 carbon atoms, which may optionally further contain one or more oxygen ether atoms, which may be an alkoxy or polyalkoxy group, or which may optionally contain one or more silane, siloxane, or polysiloxane groups, where the polysiloxane or siloxane group may contain 1-3 alkyl or alkenyl groups on the silicon atom, the maximum number of silicon atoms being preferably less than 10. Preferably, R is selected from an alkyl having 1-10 carbon atoms, which may optionally further contain one or more oxygen ether atoms, which may be an alkoxy or polyalkoxy group, or which may optionally contain one or more silane, siloxane, or polysiloxane groups, where the polysiloxane or siloxane group may contain 1-3 alkyl or alkenyl groups on the silicon atom, the maximum number of silicon atoms being preferably less than 10. 10 -alkyl group, more preferably a C1-C7-alkyl group, most preferably R is methyl.

[0022] In another preferred embodiment of the present disclosure, the unsaturated siloxane coupling agent is cyclic and has the formula (3): [ka] where n is 1, 2, 3 or 4, preferably n is 1 or 2, and each R1 is as described in formula (1), preferably at least one, more preferably all R1 represent a vinyl (-CH=CH2) group. Each R2 is as described in formula (1) above. Preferably at least one R2 is a C1-C7-alkyl group, more preferably at least one R2 is methyl. Most preferably all R2 represent a methyl group.

[0023] In one embodiment of the present disclosure, the unsaturated siloxane coupling agent has the following general formula (4): [ka] where n is an integer from 1 to 20, m is an integer from 1 to 20, and each R group is selected independently and is as described above with respect to formula (2); R3 is H, OH, a saturated or unsaturated hydrocarbon having 1 to 10 carbon atoms, a monovalent siloxane, polysiloxane, or silane; or R3 combines with R5 to form a cyclic compound and represents a divalent siloxane or polysiloxane having 1 to 10 silicon atoms, where one or at least one silicon atom has one or more alkyl or alkenyl groups having 1 to 10 carbon atoms; or R3 and R5 together form a chemical bond to form a cyclic compound; R4 is a linker group selected from (i) an aliphatic hydrocarbon having 1 to 20 carbon atoms, optionally containing one or more oxygen ether groups, (ii) one or more silane or siloxane groups, or a combination thereof, in which one or more silicon atoms may bear one or more aliphatic hydrocarbon groups having 1 to 10 carbon atoms, or a combination of (i) and (ii); R5 is H, OH, a saturated or unsaturated hydrocarbon having 1 to 10 carbon atoms, a monovalent siloxane, polysiloxane, or silane; or R5 represents a divalent siloxane or polysiloxane having 1 to 10 silicon atoms, which combines with R3 to form a cyclic compound, wherein one or at least one silicon atom has one or more alkyl or alkenyl groups having 1 to 10 carbon atoms; or R5 represents a divalent siloxane or polysiloxane having 1 to 10 silicon atoms, which combines with R3 to form a cyclic compound, wherein one or at least one silicon atom has one or more alkyl or alkenyl groups having 1 to 10 carbon atoms; or R3 and R5 together form a chemical bond to form a cyclic compound.

[0024] Preferably, the coupling agent of the present disclosure is not a polycyclic compound. One embodiment of the polycyclic compound is represented by the following formula (5): [ka] Corresponds to.

[0025] In formula (5), Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh are each the same or different and each independently represent C1-C 10 -Alkyl, C2-C6-alkenyl, -O-Si-(R 1’ R 2’ R 3’ wherein R1', R2', and R3' are each independently selected from C1-C 10 -alkyl, C2-C6-alkenyl, for example vinyl, for example at least one of R1', R2', and R3' comprises a vinyl unit, or all of R1', R2', and R'3 are vinyl (-CH=CH2). At least one, or at least two, or at least three of Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh comprise C2-C6-alkenyl, for example vinyl (-CH=CH2). In one embodiment of the polycyclic coupling agent according to formula (5), at least four of Ra to Rh are vinyl, or at least one of the groups Ra to Rh is -O-Si(vinyl)3. In another embodiment of the compound according to formula (5), all of Ra to Rh are vinyl. The compound according to formula (5) is also known as polyhedral oligomeric silsesquioxanes or POSS. These materials are commercially available or can be prepared, for example, as described in Quirk, Cheng et al, Macromolecules 2012, 45, 21, 8571-8579.

[0026] Preferably, the coupling agent according to the present disclosure has a molecular weight of 5000 g / mol or less. Preferably, the coupling agent has a molecular weight of less than 2000 g / mol.

[0027] Particularly preferred examples of coupling agents according to the present disclosure include 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane and 1,3,5-trivinyl,1,3,5-trimethylcyclotrisiloxane: [ka]

[0028] Not only can one or combinations of coupling agents according to the present disclosure be used, but also combinations of one or more coupling agents of the present disclosure with one or more other coupling agents.

[0029] polymer In one aspect of the present disclosure, there is provided a polymer obtainable by a process comprising the steps of (i) polymerizing at least one conjugated diene monomer to produce a polymer having reactive chain ends, and (ii) reacting at least a portion of the reactive polymer chain ends with at least one siloxane-based coupling agent according to the present disclosure. The conjugated diene monomer preferably has from 4 to 25, more preferably from 4 to 20 carbon atoms.

[0030] The polymer may be a homopolymer or a copolymer and comprises units derived from at least one conjugated diene monomer. Suitable diene monomers include, but are not limited to, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene, myrcene, ocimene, farnesene, and combinations thereof. Preferably, the polymer comprises or consists exclusively of units derived from 1,3-butadiene.

[0031] In one embodiment of the present disclosure, the polymer is a copolymer obtained by a process comprising a polymerization reaction comprising at least two conjugated dienes. In another embodiment, in the present disclosure, the polymer is a copolymer obtained by a process comprising the polymerization of at least one conjugated diene monomer and at least one vinyl aromatic comonomer. Examples of suitable vinyl aromatic comonomers include, but are not limited to, styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, para-tert-butylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and combinations thereof. Styrene is particularly preferred.

[0032] In one embodiment of the present disclosure, the polymer is a butadiene polymer, including homopolymers and copolymers of 1,3-butadiene. Preferably, the polymer according to the present disclosure comprises at least 51% by weight, preferably at least 60% by weight, of units derived from 1,3-butadiene, based on the weight of the polymer. In one embodiment of the present disclosure, the diene polymer comprises at least 60% by weight, or at least 75% by weight, of units derived from 1,3-butadiene.

[0033] In one embodiment of the present disclosure, the diene polymer comprises from 0 to 49 weight percent, or from 0 to 40 weight percent, of units derived from one or more comonomers, based on the total weight of the polymer.

[0034] In one embodiment of the present disclosure, the diene polymer comprises at least 60%, or at least 70%, by weight of units derived from 1,3-butadiene and 0-40%, or 0-30%, by weight of units derived from one or more comonomers.

[0035] In one embodiment, the diene polymers of the present disclosure contain from 0 to 20 weight percent of units derived from one or more conjugated dienes other than 1,3 butadiene.

[0036] In one embodiment, diene polymers according to the present disclosure contain up to 49% by weight of units derived from one or more vinyl aromatic comonomers, preferably 5% to 40% by weight of units derived from one or more vinyl aromatic comonomers. Preferably, diene polymers of the present disclosure contain up to 49% by weight, or 0 to 40% by weight, of units derived from styrene, based on the weight of the polymer.

[0037] In one embodiment, a polymer according to the present disclosure comprises at least 75% or at least 95% by weight of units derived from one or more conjugated diene monomers. In one embodiment, a polymer according to the present disclosure comprises from 55 to 92% by weight of units derived from one or more conjugated diene monomers and from 5.8 to 45% by weight of units derived from a vinyl aromatic comonomer.

[0038] Suitable copolymerizable comonomers further include one or more alpha-olefins, such as ethene, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0039] In one embodiment, the diene polymers according to the present disclosure contain from 0 to 20 weight percent of units derived from ethene, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0040] Suitable comonomers also include, but are not limited to, one or more other copolymerizable comonomers that introduce functional groups, including crosslinking sites, branching sites, branching, or functionalized groups. In one embodiment of the present disclosure, the diene polymer comprises 0 to 10% or 0 to 5% by weight of units derived from one or more such other comonomers.

[0041] Combinations of one or more comonomers of the same chemical type as those mentioned above, as well as combinations of one or more comonomers of different chemical types, can be used.

[0042] The diene polymers according to the present disclosure may have a Mooney viscosity ML1+4 at 100° C. of from 10 to 200 Mooney units, for example from 30 to 150 or from 35 to 85 Mooney units.

[0043] The diene polymer according to the present disclosure may have a number average molecular weight (Mn) of 10,000 g / mol to 2,000,000 g / mol, or 100,000 to 1,000,000 g / mol, for example 100,000 to 400,000 g / mol, or 200,000 to 300,000 g / mol. In one embodiment of the present disclosure, the Mn of the polymer is 150 kg / mol to 320 kg / mol.

[0044] The diene polymers according to the present disclosure can have a dispersity (also referred to herein as molecular weight distribution or MWD) of 1.03 to 25, for example, 1.03 to 5. In one embodiment of the present disclosure, the polymers have an MWD of 1.03 to 3.5 or 1.03 to 2.0. MWD is the ratio of weight average molecular weight (Mw) to number average molecular weight Mn, i.e., MWD is equal to Mw / Mn.

[0045] The diene polymers according to the present disclosure are rubbers and typically have a glass transition temperature below 20° C. They may have a glass transition temperature (Tg) of, for example, −120° C. to below 20° C. In a preferred embodiment of the present disclosure, the polymer has a Tg of 0° C. to −110° C. or −10° C. to −80° C. In one embodiment of the present disclosure, the butadiene polymer has a glass transition temperature of about −50 to −80° C.

[0046] In one embodiment of the present disclosure, the diene polymer has a number average molecular weight of 100,000 to 1,000,000, a Mooney viscosity ML1+4 at 100°C of 30 to 150 units, and a glass transition temperature of -110°C to 0°C.

[0047] In one embodiment, the diene polymer according to the present disclosure has a Mooney viscosity ML1+4 at 100° C. of 30-150 units, a number average molecular weight of 100,000-400,000 g / mol, a glass transition temperature of −110° C.-0° C., and a molecular weight distribution (MWD) of 1.03-20.

[0048] The diene polymer according to the present disclosure may be further functionalized and may contain one or more functional groups, preferably terminal groups, which contain, in addition to C and H atoms, at least one heteroatom selected from Si, S, N, O, and combinations thereof. Such further functionalized polymers may be obtained, for example, by a reaction comprising reacting a reactive polymer chain end with at least one functionalizing reagent, which contains, in addition to C and H atoms, at least one heteroatom selected from Si, S, N, O, and combinations thereof. The at least one functionalizing reagent may be reacted with the polymer before, during or after, preferably after, the reaction of the polymer with the coupling agent. If necessary, the reaction product of this functionalization reaction may then be treated to add at least one -OH group, -SH group, or -COOH group, or combinations thereof, or -O group, or -SH group, or -COOH group, or -O ... - group, -S - Group, -COO - The anionic forms thereof may be selected from the group consisting of at least one -OH, -SH, or -COOH group, or a combination thereof, or a combination thereof. - , -S - , -COO - Such treatment may include a hydrolysis reaction, for example by adding an alcohol or an acid, or may involve treatment with at least one other functionalizing reagent that reacts with the first functionalizing reagent to produce their anionic form selected from.

[0049] Polymer manufacturing method The homopolymers or copolymers of the present disclosure can be prepared by methods known in the art. Polymerization can be carried out to produce statistical polymers, also called random copolymers, block copolymers, gradient copolymers, or combinations thereof, and can include linear and branched structures known to those skilled in the art.

[0050] The polymers can be obtained by a process comprising anionic or catalytic polymerization using one or more coordination catalysts. Coordination catalysts in this context include Ziegler-Natta catalysts or monometallic catalyst systems. Preferred coordination catalysts are based on Ni, Co, Ti, Zr, Nd, V, Gd, Cr, Mo, W, or Fe. Preferably, the polymerization reaction comprises anionic solution polymerization. Initiators for anionic solution polymerization include organometallics, preferably based on alkali metals or alkaline earth metals. Examples include methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, pentyllithium, n-hexyllithium, cyclohexyllithium, octyllithium, decyllithium, 2-(6-lithio-n-hexoxy)tetrahydropyran, 3-(tert-butyldimethylsiloxy)-1-propyllithium, phenyllithium, 4-butylphenyllithium, 1-naphthyllithium, p-toluyllithium, and allyllithium compounds derived from tertiary N-allylamines, such as [1-(dimethylamino)-2-propyllithium]. The allyl lithium compounds and the lithium amides may be prepared in situ by reacting an organolithium compound with the respective tertiary N-allyl amine or the respective secondary amine. Bifunctional and polyfunctional organolithium compounds may also be used, such as 1,4-dilithiobutane, dilithium piperazine. Preferably, n-butyl lithium, sec-butyl lithium, or a combination thereof is used.The initiator forms an anionically reactive monomer, which then propagates through the reaction of the reactive carbanion monomer with another monomer to form a reactive carbanion polymer chain end, or, in the case of polymerizations using one or more coordination catalysts, the reactive chain end is formed by the catalyst.

[0051] Randomizers and control agents known in the art can be used during polymerization to control the structure of the polymer, particularly to avoid aggregation or to increase disorder. Such agents include, for example, diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, ethylene glycol di-tert-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether, diethylene glycol di-tert-butyl ether, 2-(2-ethoxyethoxy)-2-methyl-propane, triethylene glycol dimethyl ether, tetrahydrofuran, ethyl tetrahydrofurfuryl ether, hexyl tetrahydrofurfuryl ether, 2,2-bis(2-tetrahydrofuryl)propane, dioxane, trimethylamine, triethylamine, N,N,N',N'-tetramethyl-ethylenediamine, N-methylmorpholine, N-ethylmorpholine, 1,2-dipiperidinoethane, 1,2-dipyrrolidinoethane, 1,2-dimorpholinoethane, potassium and sodium salts including the potassium and sodium salts of alcohols, phenols, carboxylic acids, sulfonic acids, and combinations thereof. In one embodiment of the present disclosure, the polymer is a random polymer, and preferably, at least one randomizer is used in the polymerization reaction.

[0052] In one embodiment of the present disclosure, the polymer is a random polymer. In one embodiment, the polymer is a block copolymer. To produce a block copolymer, the polymerization is preferably started with one monomer, followed by the addition of another (co)monomer, depending on the size of the block to be produced. The order of monomer addition can be adapted depending on which blocks of different monomers are desired to be formed. In one embodiment of the present disclosure, such blocks are formed at the beginning or end of the polymerization, or both.

[0053] In one embodiment, the polymerization is carried out in the presence of at least one solvent, preferably in solution. Preferred solvents for solution polymerization include inert aprotic solvents, such as aliphatic hydrocarbons. Specific examples include, but are not limited to, butane, pentane, hexane, heptane, octane, decane, and cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, 1,4-dimethylcyclohexane, and combinations thereof, including their isomers. Further examples include alkenes, such as 1-butene, or aromatic hydrocarbons, such as benzene, toluene, ethylbenzene, xylene, diethylbenzene, or propylbenzene, and combinations thereof. These solvents can be used individually or as mixtures. Preferred solvents include cyclohexane, methylcyclopentane, and n-hexane. If appropriate, these solvents can also be mixed with polar solvents.

[0054] The polymerization can be carried out by first introducing the (co)monomer and the solvent and then initiating the polymerization by adding the initiator or catalyst. The polymerization can also be carried out in a feed process where the polymerization reactor is filled by adding the monomer and the solvent. The initiator or catalyst is introduced or added together with the monomer and the solvent. Variants such as introducing the solvent into the reactor, adding the initiator or catalyst, followed by the monomer can be used. The polymerization can be carried out in a continuous or batch mode. Additional monomer and solvent can be added during or at the end of the polymerization.

[0055] The polymerization can be carried out at normal or elevated pressure (e.g., 1-10 bar) or reduced pressure. Typical reaction temperatures include room temperature, but depending on the nature and amount of comonomer, the reaction temperature can be higher or lower than room temperature. Typical ranges include, for example, -12°C to 140°C in a continuous adiabatic process, or 50-120°C in a batch process.

[0056] The polymerization reaction results in reactive polymer chain ends, preferably anionic chain ends. At a desired degree of progress of the polymerization reaction, for example when a desired conversion of the polymer or a desired molecular weight range has been achieved, the polymerization mixture or solution containing the reactive polymer chain ends is contacted with at least one siloxane-based coupling agent according to the present disclosure. Typically, it is desirable to carry out the coupling reaction at the end of the polymerization reaction, for example after at least 90%, or at least 95% of the monomer has been consumed. For example, the coupling agent can be added before or after the monomer feed is stopped or interrupted. The coupling agent can be added as a pure substance or as a solution or dispersion. Although not preferred or necessary, coupling agents other than the unsaturated siloxane according to the present disclosure can be further used. Typically, the addition of the coupling agent is carried out at a reaction temperature of 20°C to 130°C, or 50°C to 130°C.

[0057] Another advantage of using siloxane-based coupling agents to prepare diene rubbers is that the polymers obtained using them can be further functionalized to prepare diene rubbers with additional functional groups, preferably terminal groups. Thus, the method according to the present disclosure can further comprise a step of reacting the polymer with at least one functionalizing agent to introduce at least one functional group into the polymer, which can be carried out before, after or during step (ii). Typically, such functionalizing reactants are aliphatic compounds that contain, in addition to carbon and hydrogen atoms, heteroatoms selected from Si, O, S and N, preferably combinations of heteroatoms selected from Si and O, combinations selected from Si, O and S, and combinations of Si, O and N, or combinations of N and O. Typically, they provide polymers with at least one polar group selected from -OH, -COOH, -SH, or salts thereof, and combinations thereof, either directly or by hydrolysis or reaction with another functionalizing agent, or both. Typically, the functionalizing agent has a molecular weight of less than 5,000 g / mole, or even less than 2,000 g / mole.

[0058] Any functionalizing reactant known in the art can be used. Examples of functionalizing agents include, but are not limited to, linear or branched alkoxysilanes and those described in US Patent Application Publication No. 2013 / 0281605A1, US Patent Application Publication No. 2013 / 0338300A1, US Patent Application Publication No. 2013 / 0280458A1, US Patent Application Publication No. 2016 / 0075809A1, US Patent Application Publication No. 2016 / 0083495A1, WO 2021 / 009154A1, US Patent No. 4,894,409, and WO 2021 / 009156.

[0059] Preferred functionalizing agents include linear or branched alkoxysilanes, linear or branched silanes, and [ka] and combinations thereof.

[0060] In one embodiment of the present disclosure, the functionalizing reactant is a linear or branched silane or siloxane. In another embodiment of the present disclosure, the functionalizing reactant is a cyclic reactant. In one embodiment of the present disclosure, the functionalizing reactant is cyclic and has a 4-7 membered aliphatic cyclic ring, more preferably a 5- or 6-membered aliphatic cyclic ring, any of which has at least 2, preferably at least 3 carbon atoms and at least one heteroatom selected from N, O, S, Si, or a combination thereof. In another embodiment of the present disclosure, the functionalizing reactant is cyclic and has a 3-20 membered ring structure, the ring has at least 2, preferably at least 3 -Si(R1R2)-O- units, where R1 and R2 are each independently selected from H, C1-C1-C2 ... 10 C1-C2 saturated hydrocarbon groups, optionally containing one or more heteroatoms selected from O, N, S, Si, or combinations thereof. 10 Preferably, R1 and R2 are selected from methyl, ethyl, propyl, and butyl.

[0061] A functionalizing reagent according to formula (6): Reactants according to formula (6) include cyclosiloxane-based functionalized reactants. In formula (6), R1 and R2 may be the same or different and may be H, C1-C 10 Corresponding to saturated hydrocarbon radicals, preferably methyl, ethyl, propyl, and butyl, where C1-C 10The saturated hydrocarbon group may optionally contain one or more heteroatoms selected from O, N, S, Si, or combinations thereof, where n is an integer selected from 3 to 10, preferably 4 to 6. Specific examples of reactants according to formula (6) include, but are not limited to, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane, and as described, for example, in U.S. Patent Application Publication No. 2016 / 0075809 A1, reactants according to formula (6) may be directly or indirectly (e.g., by subsequent hydrolysis) converted to silanols (-Si(R1)(R2)-OH) or silanolates (-Si(R1)(R2)-O-H). - ) group).

[0062] Functionalizing reagents according to formula (7): Reactants according to formula (7) include silalactone-based functionalizing reactants. 1 and R 2 are the same or different and are each selected from H or a group having 1 to 20 carbon atoms, preferably selected from alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, aryloxy, alkaryl, alkaryloxy, aralkyl, or aralkoxy; R 3 , R 4 are the same or different and each is selected from H or a group having 1 to 20 carbon atoms, preferably alkyl, cycloalkyl, aryl, alkaryl, or aralkyl, A is a divalent organic group, preferably a divalent organic group having 1 to 26 carbon atoms and optionally containing, in addition to hydrogen atoms, heteroatoms selected from O, N, S, and Si.

[0063] Preferably R 1 , R 2 are the same or different, H, (C1-C 24 )-Alkyl, (C1-C 24 )-alkoxy, (C3-C 24)-Cycloalkyl, (C3-C 24 )-Cycloalkoxy, (C6-C 24 )-aryl, (C6-C 24 )-aryloxy, (C6-C 24 )-alkaryl, (C6-C 24 )-alkaryloxy, (C6-C 24 )-aralkyl, or (C6-C 24 )-aralkoxy groups, which may optionally contain one or more heteroatoms selected from O, N, S or Si.

[0064] Preferably R 3 , R 4 are the same or different, H, (C1-C 24 )-Alkyl, (C3-C 24 )-cycloalkyl, (C 6- C 24 )-aryl, (C6-C 24 )-alkaryl, or (C6-C 24 )-aralkyl groups, which may optionally contain one or more heteroatoms selected from O, N, S, or Si.

[0065] In one embodiment of the present disclosure, A is: -Xn-(CY1H)m-(CY2Y3)o-(CY1H)p- wherein n is 1 or 0, m is 1, 2, 3, or 4, o is 0, 1, or 2, and p is 0, 1, or 2, preferably the sum of n, m, o, and p is 2 or 3; X is O, S, NR, where R is H, or C1-C3 alkyl, or X is N(Si(alkyl)3), where each "alkyl" independently represents C1-C6 alkyl, -oxyalkyl, or alkoxy; Y1 is H or C1-C3 alkyl, Y2 is H or C1-C3 alkyl, and Y3 is H or C1-C3 alkyl, preferably at least one of Y2 and Y3 is H.

[0066] As a specific example of a non-limiting example: -CH2-;-CH2CH2-;-CH2CH2CH2-;-C(CH3)-CH2-;-CH2-C(CH3)-CH-;-CH(CH3)-C(CH3)H-; -CH(CH3)-CH2-C(CH3)H-;-CH2-C(CH3)HC(CH3)H-;-CH(CH3)-C(CH3)H-CH2-;-O-CH2-; -O-CH2CH2-;-O-CH2CH2-CH2-;-OC(CH3)H-;-O-CH2CH2-;-OC(CH3)H-CH2-; -O-CH2-C(CH3)H-;-O-CH2-C(CH3)H-CH2-;-O-CH2CH2-C(CH3)H-;-OC(CH3)H-CH2-CH2-; -S-CH2-;-S-CH2CH2-;-S-CH2CH2-CH2-;-SC(CH3)H-;-S-CH2CH2-;-SC(CH3)H-CH2-; -S-CH2-C(CH3)H-;-S-CH2-C(CH3)H-CH2-;-S-CH2CH2-C(CH3)H-;-SC(CH3)H-CH2-CH2-; -NH-CH2-;-NH-CH2CH2-;-NH-CH2CH2-CH2-;-NH-C(CH3)H-CH2-;-NH-CH2-C(CH3)H-; -NH-CH2-C(CH3)H-CH2-;-NH-CH2CH2-C(CH3)H-;-NH-C(CH3)H-CH2-CH2-; -N(CH3)-CH2-;-N(CH3)-CH2-;-N(CH3)-CH2CH2-;-N(CH3)-CH2CH2-CH2-; -N(CH3)-C(CH3)H-CH2-;-N(CH3)-CH2-C(CH3)H-;-N(CH3)-CH2-C(CH3)H-CH2-; -N(CH3)-CH2CH2-C(CH3)H-; -N(CH3)-C(CH3)H-CH2-CH2-; N(Si(alkyl)3)-CH2-;-N(Si(alkyl)3)-CH2CH2-;N(Si(alkyl)3)-CH2CH2CH2-; -N(Si(alkyl)3)-C(CH3)H-;-N(Si(alkyl)3)-CH2CH2-;-N(Si(alkyl)3)-C(CH3)H-CH2-; -N(Si(alkyl)3)-CH2-C(CH3)H-;-N(Si(alkyl)3)-CH2-C(CH3)H-CH2-; -N(Si(alkyl)3)-CH2CH2-C(CH3)H-;-N(Si(alkyl)3)-C(CH3)H-CH2-CH2- Examples include:

[0067] Examples of reactants according to formula (7) are: 2,2-dimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,4-trimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,5-trimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,4,5-tetramethyl-1-oxa-2-silacyclohexane-6-one, 2,2-diethyl-1-oxa-2-silacyclohexane-8-one, 2,2-diethoxy-1-oxa-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-2-silacyclohexane-8-one, 2,2-dimethyl-1-oxa-2-silacyclohexane-6 ... ,4-dioxa-2-silacyclohexane-6-one, 2,2,5-trimethyl-1,4-dioxa-2-silacyclohexane-6-one, 2,2,3,3-tetramethyl-1,4-dioxa-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexane-6-one, 2,2-diethyl-1-oxa-4-thia-2-silacyclohexane-6-one, 2,2-diphenyl-1-oxa-4-thia-2-silacyclone-6-one, 2-methyl-2-ethenyl-1-oxa sa-4-thia-2-silacyclohexane-6-one, 2,2,5-trimethyl-1-oxa-4-thia-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,4-dimethyl-2-phenyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,2-dimethyl-4-trimethylsilyl-1-oxa-4-aza-2-silacyclohexane-8-one, 2,2-diethoxy-4-methyl-1-oxa-4-aza-2-silacyclohexan-6-one, 2,2,4,4-tetramethyl-1-oxa-2,4-disilacyclohexan-8-one, 3,4-dihydro-3,3-dimethyl-1H-2,3-benzoxasilin-1-one, 2,2-dimethyl-1-oxa-2-silacyclopentan-5-one, 2,2,3-trimethyl-1-oxa-2-silacyclopenten-5-one, 2,2-dimethyl-4-phenyl-1-oxa-2-silacyclopentan-5-one, 2,Examples of the 2-methyl-2-(2-propen-1-yl)-1-oxa-2-silacyclopentan-5-one include 2,4-tert-butyl-1-oxa-2-silacyclopentan-5-one, 2-methyl-2-(2-propen-1-yl)-1-oxa-2-silacyclopentan-5-one, 1,1-dimethyl-2,1-benzoxasirol-3(1H)-one, and 2,2-dimethyl-1-oxa-2-silacycloheptan-7-one.

[0068] Reactants according to formula (7) are described in US Patent Application Publication No. 2016 / 0075809, particularly in paragraphs

[0034] to

[0042] . Such reactants can be used alone or in addition to another functionalizing reactant, such as a reactant according to formula (6), to provide silacarboxylate groups, such as those of the general formula: -Si(R 1 )(R 2 )-C(R 3 )(R 4 )-A-COO - It is possible to form a group according to the formula:

[0069] Functionalizing reagents according to formula (8): Reactants according to formula (8) include oxa-silacycloalkanes. 1 , R 2 , R 3 , R 4 , and A are the same as those described in formula (7).

[0070] Examples of specific reactants according to formula (8) include: 2,2-dimethyl-1-oxa-2-silacyclohexane, 2,2-diethyl-1-oxa-2-silacyclohexane, 2,2-dipropyl-1-oxa-2-silacyclohexane, 2-methyl-2-phenyl-1-oxa-2-silacyclohexane, 2,2-diphenyl-1-oxa-2-silacyclohexane, 2,2,5,5-tetramethyl-1-oxa-2-silacyclohexane, 2,2,3-trimethyl-1-oxa-2-silacyclohexane, 2,2-dimethyl Examples of the reactants according to formula (8) include aryl-1-oxa-2-silacyclopentane, 2,2,4-trimethyl-1-oxa-2-silacyclopentane, 2,2-dimethyl-1,4-dioxa-2-silacyclohexane, 2,2,5,5-tetramethyl-1,4-dioxa-2,5-disilacyclohexane, 2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane, benzo-2,2-dimethyl-1,4-dioxa-2-silacyclohexane, and benzo-2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane. The reactants according to formula (8) are described, for example, in US Patent Application Publication No. 2013 / 0281605 A1. By using the reactants according to formula (8), the compounds of formula -S(R 1 )(R 2 )-C(R 3 )(R 4 )-A-OH can be obtained as a corresponding carbinol group.

[0071] A functionalizing reagent according to formula (9): Reactants according to formula (9) include bis(trialkylsilyl)peroxides. 1 , R 2 , and R 3 are selected from linear, branched or cyclic alkyl, which may be the same or different and may optionally contain heteroatoms selected from O, N, S and Si, and combinations thereof. Preferably, they are selected from C1-C10 linear alkyl, and preferably they are all the same. Preferably, R 1 , R 2 , and R 3At least one of them is methyl, and more preferably all of them are methyl.

[0072] Functionalizing reagents according to formula (10): The reactant according to formula (10) includes cyclic urea. In formula (10), R3 represents a divalent, saturated or unsaturated, linear or branched, preferably aliphatic, hydrocarbon group having 1 to 20 carbon atoms and, in addition to C and H, may contain one or more heteroatoms, preferably selected independently from O, N, S, or Si. Preferably, R3 represents a group represented by the general formula (11): -[CHX 1 ] o -[CHX 2 ] p -[O] z -[CHX 3 ] q - (11) where z is 1 or 0, and o, p, and q are independently selected from 0, 1, and 2, with the proviso that at least one of o, p, and q is not 0. 1 , X 2 , and X 3 is independently selected from H, linear or branched alkyl, alkylaryl, and aryl groups having 1 to 12 carbon atoms, and aminoalkyl (NR) groups, R is a linear, branched, or cyclic alkyl or alkylaryl group having 1 to 12 carbon atoms, and X 1 and X 2 can represent chemical bonds between them to form carbon-carbon bonds to obtain unsaturation in the carbon chain. 1 , X 2 , and X 3 is selected such that the total number of carbon atoms is 20 or less.

[0073] In one embodiment of the present disclosure, R3 is selected from substituted alkylene, e.g., X 1 , X 2 , and X 3 is selected from substituted alkylenes corresponding to formula (11) in which at least one of is not H.

[0074] In one embodiment of the present disclosure, R3 is selected from unsubstituted alkylene, e.g., X 1 , X 2 , and X 3 is selected from unsubstituted alkylene corresponding to formula (11) in which all of are H. In one preferred embodiment, R3 is -[(CH)2] n -, where n is an integer of 1 to 5, preferably 1 to 3, and more preferably 1 or 2.

[0075] In one embodiment of the present disclosure, R3 is selected from unsaturated substituted or unsubstituted alkylene, e.g., X 1 and X 2 taken together to form a carbon-carbon bond. Specific examples of unsaturated alkylene include, but are not limited to, -CH=CH- or -CH2-CH=CH-.

[0076] In formula (10), R1 and R2 are the same or different and represent a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, where the hydrocarbon group may contain, in addition to C atoms and H atoms, one or more heteroatoms, preferably selected from the group consisting of O, N, S, and Si. For example, R1 and R2 may be the same or different and may contain one or more heteroatoms, preferably independently selected from O, N, S, or Si, -(C1-C 20 )-alkyl group, -(C3-C 20 )-cycloalkyl group, -(C6-C 20 )-aryl group, -(C6-C 20 )-alkaryl group, or -(C6-C 20 Preferably, R1, R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, trialkylsilyl having alkyl groups of 1 to 4 carbon atoms per alkyl group, phenyl, and phenyl independently substituted with one, two or three methyl, ethyl, propyl and / or butyl groups.

[0077] Preferred examples of substances according to formula (10) include 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-phenyl-2-imidazolidinone, 1,3-diphenyl-2-imidazolidinone, 1,3,4-trimethyl-2-imidazolidinone, 1,3-bis(trimethylsilyl)-2-imidazolidinone, 1,3-dihydro-1,3-dimethyl-2H-imidazol-2-one, tetrahydro-1,3-dimethyl-2( Examples of the 1H)-pyrimidinone include, but are not limited to, tetrahydro-1-methyl-3-phenyl-2(1H)-pyrimidinone, tetrahydro-1,3,5-trimethyl-2(1H)-pyrimidinone, tetrahydro-3,5-dimethyl-4H-1,3,5-oxadiazin-4-one, tetrahydro-1,3,5-trimethyl-1,3,5-triazin-2(1H)-one, hexahydro-1,3-dimethyl-2H-1,3-diazepin-2-one. A particularly preferred example is 1,3-dimethyl-2-imidazolidinone, also known as DMI, i.e., R3 is -CH2-CH2- and / or both R1 and R2 are -CH3.

[0078] Reactants according to formula (10) are described, for example, in U.S. Pat. No. 4,894,409 and in international patent applications WO 2021 / 009154 and WO 2021 / 009156.

[0079] The functionalizing reagents mentioned above are capable of reacting with the reactive chain ends of the polymer and are therefore also referred to herein as "omega-functionalizing reagents". Instead of or in addition to the addition of an omega-functionalizing reagent, an "alpha-functionalizing reagent" can be added at the start of the polymerization, for example as a functionalizing initiator. Typically, this results in an alpha-functionalized polymer, i.e. a polymer with a polar group at the beginning of the chain. Examples of alpha-functionalizing reagents are described in EP 2847264 A1 and EP 2847242 A1.

[0080] If the polymerization reaction is not initiated by reaction with a coupling agent or optionally with one or more omega functionalizing agents as described above, the polymerization reaction can be terminated, for example, by quenching. Quenching agents known in the art can be used. Typical quenching agents for terminating polymerization include alcohols, such as octanol.

[0081] The polymer can be post-treated and isolated as known in the art. Antioxidants known in the art, such as sterically hindered phenols, aromatic amines, phosphites, thioethers, etc., can be added to the reaction mixture. Preferably, they can be added before or during the post-treatment of the polymer of the present disclosure. Extender oils used in diene rubbers, such as TDAE (Treated Distillate Aromatic Extract), MES (Mild Extraction Solvates), RAE (Residual Aromatic Extract), TRAE (Treated Residual Aromatic Extract), naphthenic oils, and heavy naphthenic oils, can be added to the reaction mixture before or during the post-treatment to obtain oil-extended rubber. The solvent can be removed by conventional methods such as distillation, stripping with steam, or by using vacuum or reduced pressure, at high temperatures if necessary. Typically, the solvent is reused (recycled). The polymer crumb may be further dried on the mill or processed on the mill, for example converted into sheets, or compressed, for example into bales.

[0082] Rubber Compound The polymers according to the present disclosure can be used to make rubber compounds. The rubber compounds can be prepared by a process that includes mixing at least one polymer according to the present disclosure with at least one filler. The rubber compounds can be vulcanizable and can further include one or more curatives. The curatives can crosslink (cure) the diene polymers and are also referred to herein as "crosslinking agents" or "vulcanizing agents." Suitable curatives include, but are not limited to, sulfur, sulfur-based compounds, and organic or inorganic peroxides.

[0083] In a preferred embodiment of the present disclosure, the curing agent comprises sulfur. Instead of a single curing agent, a combination of one or more curing agents can be used, or a combination of one or more curing agents and one or more curing accelerators or curing catalysts can be used. Examples of sulfur-containing compounds that act as sulfur donors include, but are not limited to, sulfur, sulfur halides, dithiodimorpholine (DTDM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), and dipentamethylenethiuram tetrasulfide (DPTT). Examples of curing accelerators include, but are not limited to, amine derivatives, guanidine derivatives, aldehyde amine condensation products, thiazoles, thiuram sulfides, dithiocarbamates, and thiophospahtes.

[0084] In another embodiment of the present disclosure, the curing agent includes peroxide.Examples of peroxides used as vulcanizing agents include, but are not limited to, di-tert-butyl-peroxide, di-(tert-butyl-peroxy-trimethyl-cyclohexane), di-(tert-butyl-peroxy-isopropyl)benzene, dichloro-benzoyl peroxide, dicumyl peroxide, tert-butyl-cumyl-peroxide, dimethyl-di(tert-butyl-peroxy)hexane, and dimethyl-di(tert-butyl-peroxy)hexyne, and butyl-di(tert-butyl-peroxy)valerate.If necessary, sulfenamide type, guanidine type, or thiuram type vulcanization accelerators can be used together with the vulcanizing agent.

[0085] If added, the vulcanizing agent is typically present in an amount of from 0.5 to 10 parts by weight, preferably from 1 to 6 parts by weight, per 100 parts by weight of rubber.

[0086] The rubber compound is suitable for the manufacture of tires or tire components such as sidewalls or tire treads. The tire or tire components include the rubber compound, which is typically in a vulcanized form.

[0087] Conventional fillers can be used. Conventional fillers include silica and carbon-based fillers, such as carbon black. The fillers can be used alone or in mixtures. In a particularly preferred form, the rubber composition comprises a mixture of silica filler and carbon black. The mass ratio of silica filler to carbon black can be from 0.01:1 to 50:1, preferably from 0.05:1 to 20:1.

[0088] Preferably, the filler has a viscosity of preferably 5 to 1,000, preferably 20 to 400 m 2Examples of suitable fillers include silica-containing particles having a BET surface area (nitrogen absorption method) of 1000 nm / g. Such fillers can be obtained, for example, by precipitation from a solution of silicates or by flame hydrolysis of silicon halides. The silica-containing filler particles can have a particle size of 10 to 400 nm. The silica-containing filler can also contain oxides of Al, Mg, Ca, Ba, Zn, Zr, or Ti. Another example of a silicon oxide-based filler is aluminum silicate, preferably 20 to 400 m. 2 Examples of fillers include alkaline earth metal silicates such as magnesium silicate or calcium silicate having a BET surface area of ​​1000 nm / g and a primary particle size of 10 to 400 nm, natural silicates such as kaolin, and other natural silicates such as clays (layered silica). Further examples of fillers include fillers based on glass particles such as glass beads, microspheres, glass fibers, and glass fiber products (mats, strands).

[0089] Polar fillers, such as silica-containing fillers, can be modified to make them more hydrophobic. Suitable modifiers include silanes or silane-based compounds. Typical examples of such modifiers include, but are not limited to, those represented by the following general formula (7): (R 1 R 2 R 3 O)3Si-R 4 -X (7) In particular, compounds corresponding to the formula 1 , R 2 , R 3 are each independently an alkyl group, preferably R 1 , R 2 , R 3 are all methyl or all ethyl, R 4 is an aliphatic or aromatic linking group having 1 to 20 carbon atoms, and X is a sulfur-containing functional group selected from -SH, -SCN, -C(=O)S, or a polysulfide group.

[0090] Alternatively or in addition to silica modified as described above, such modification can be carried out in situ, for example during compounding or during the manufacturing process of the tire or a component thereof, for example by adding a modifier, preferably a silane or a silane modifier, for example according to formula (7), during the manufacture of the rubber compound.

[0091] Fillers based on metal oxides other than silicon oxide include, but are not limited to, zinc oxide, calcium oxide, magnesium oxide, aluminum oxide, and combinations thereof. Alternative fillers include metal carbonates, such as magnesium carbonate, calcium carbonate, zinc carbonate, and combinations thereof, metal hydroxides, such as aluminum hydroxide, magnesium hydroxide, and combinations thereof, alpha-beta-unsaturated fatty acids having 3 to 8 carbon atoms and salts of acrylic or methacrylic acid, such as zinc acrylate, zinc diacrylate, zinc methacrylate, zinc dimethacrylate, and mixtures thereof.

[0092] In another embodiment of the present disclosure, the rubber compound includes one or more carbon-based fillers, such as one or more carbon blacks. The carbon blacks can be produced, for example, by the lamp black process, the furnace black process, or the gas black process. Preferably, the carbon black has a viscosity of 20 to 200 m. 2 / g BET surface area (nitrogen adsorption method). Suitable examples include, but are not limited to, SAF, ISAF, HAF, FEF, and GPF black.

[0093] Further examples of suitable fillers include carbon-silica dual phase fillers, lignin or lignin-based materials, starch or starch-based materials, and combinations thereof.

[0094] In a preferred embodiment, the filler comprises one or more of silicon oxide, carbon black, or a combination thereof.

[0095] Typical amounts of filler include 5 to 200 parts per 100 parts of rubber, such as 10 to 150 parts, or 10 to 95 parts by weight per 100 parts of rubber.

[0096] The rubber compound may further include one or more additional rubbers other than the diene rubber according to the present disclosure, and one or more rubber additives. Additional rubbers include, for example, natural rubber and synthetic rubber. When present, they can be used in an amount ranging from 0.5 to 95% by weight, preferably ranging from 10 to 80% by weight, based on the total amount of rubber in the composition. Examples of suitable synthetic rubbers include BR (polybutadiene), acrylic acid alkyl ester copolymer, IR (polyisoprene), E-SBR (styrene-butadiene copolymer produced by emulsion polymerization), S-SBR (styrene-butadiene copolymer produced by solution polymerization), IIR (isobutylene-isoprene copolymer), NBR (butadiene-acrylonitrile copolymer), HNBR (partially or fully hydrogenated NBR rubber), EPDM (ethylene-propylene-diene terpolymer), and mixtures thereof. Natural rubber, E-SBR and S-SBR with a glass temperature higher than -60°C, polybutadiene rubber with a high cis content (>90%) produced with catalysts based on Ni, Co, T, I or Nd, polybutadiene rubber with a vinyl content of up to 80% and mixtures thereof are of particular interest for the production of automobile tires.

[0097] The rubber compound may also include one or more rubber additives, which are components that can improve the processing characteristics of the rubber composition, that can serve to crosslink the rubber composition, that can improve the physical properties of the vulcanizates made from the rubber, that can improve the interaction between the rubber and the filler, or that can serve to bond the rubber to the filler. Rubber auxiliaries include, but are not limited to, accelerators, antioxidants, heat stabilizers, light stabilizers, ozone stabilizers, processing aids, plasticizers, tackifiers, foaming agents, dyes, pigments, waxes, extenders, organic acids, silanes, retarders, metal oxides, extender oils such as DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), MES (Mild Extraction Solvates), RAE (Residual Aromatic Extract), TRAE (Treated Residual Aromatic Extract), naphthenic oils, and heavy naphthenic oils, and activators.

[0098] The total amount of rubber additives may range from 1 to 300 parts by mass, preferably 5 to 150 parts by mass, based on 100 parts by mass of the total rubber in the composition.

[0099] The rubber composition can be prepared using conventional processing equipment for the manufacture and processing of (vulcanizable) rubber compounds, including rollers, kneaders, internal mixers, or mixing extruders. The rubber composition can be manufactured in a one-stage or multi-stage process, with 2-3 mixing stages being preferred. The crosslinking agent, e.g. sulfur, and accelerators can be added in a separate mixing stage, e.g. on a roller, with temperatures in the range of 30°C to 90°C being preferred. The crosslinking agent, e.g. sulfur, and accelerators are preferably added in the final mixing stage.

[0100] Purpose The rubber compositions according to the present disclosure may be used in the manufacture of rubber vulcanizates, particularly in the manufacture of tires, and especially tire treads.

[0101] A rubber vulcanizate can be obtained by providing a vulcanizable composition according to the present disclosure and performing at least one curing reaction thereon. The vulcanizable and / or vulcanized rubber composition can be molded before, during, or after the curing reaction. Molding can be performed by process steps including molding, extrusion, and combinations thereof.

[0102] The (vulcanizable) rubber compositions obtained herein are also suitable for the production of molded articles, such as cable sheaths, hoses, drive belts, conveyor belts, roll linings, shoe soles, sealing rings and damping elements.

[0103] Another aspect of the present disclosure relates to a molded article, particularly a tire component such as a tire tread, or a finished tire, comprising a vulcanized rubber composition obtained by vulcanization of the vulcanizable rubber composition according to the present disclosure.

[0104] The following examples are provided to further illustrate the present disclosure, but are not intended to limit the disclosure to the embodiments described in these examples. EXAMPLES

[0105] Working Example method Gel permeation chromatography (GPC) at 35° C. (THF as solvent and polystyrene calibration) was used to determine the number average molecular weight Mn, weight average molecular weight Mw, dispersity D=Mw / Mn (also referred to herein as molecular weight distribution or MWD), and degree of coupling of the polymers.

[0106] The Mooney viscosity was measured according to DIN ISO 289-1 (2018) under the measurement conditions ML(1+4) at 100 ° C. The Mooney stress relaxation (MSR) was determined from the same measurement according to ASTM D 1646-00.

[0107] The dynamic properties of the vulcanized compounds were determined in accordance with DIN 53513-1990 on an Eplexor 500 N from Gabo-Testanlagen GmbH, Ahlden, Germany, at 10 Hz in the temperature range from -100 °C to +100 °C and a heating rate of 1 K / min (sample: l * w * t=60mm * 10mm * 2 mm strip; free length between sample holders 30 mm). With this method the following properties can be determined: tan δ(60°C), i.e. the loss factor at 60°C (E” / E'); and tan δ(0°C), i.e. the loss factor at 0°C (E” / E'). tan δ(60°C) is a measure of the hysteresis loss from the tyre under driving conditions. A decrease in tan δ(60°C) reduces the rolling resistance of the tyre. tan δ(0°C) is a measure of the wet grip of the material. An increase in tan δ(0°C) increases the wet grip.

[0108] The elastic properties were determined according to DIN 53513-1990. An elastomer testing system (MTS Systems GmbH, 831 Elastomer Test System) was used. Measurements were performed in double shear mode, without static prestrain in the shear direction, on cylindrical specimens (each of the two specimens is 20 x 6 mm and precompressed to a thickness of 5 mm), with an oscillation of about 0 and a measurement frequency of 10 Hz in the strain range of 0.1 to 40%. This method was used to obtain the following properties: G'(0.5%): dynamic modulus of elasticity at 0.5% amplitude sweep, G'(15%): dynamic modulus of elasticity at 15% amplitude sweep, G'(0.5%)-G'(15%): difference in dynamic elasticity at 0.5% for 15% amplitude sweep, tan δ(max): maximum loss factor (G” / G') over the entire measurement range at 60℃.

[0109] The difference G'(0.5%)-G'(15%) is an indication of the Payne effect of the mixture. The smaller this value, the better the dispersion of the filler in the mixture and the better the rubber-filler interaction. tan δ(max) is another measure of the hysteresis loss from the tire under driving conditions. A decrease in tan δ(max) reduces the rolling resistance of the tire.

[0110] The rebound resilience was determined at 60° C. in accordance with DIN 53512.

[0111] polymer Example 1 (for comparison) An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 10 mmol n-butyllithium (as a 23 wt % solution in hexane) and stirred for 45 minutes at 70° C. The polymer solution was quenched with 10 mmol n-octanol, stabilized with 4.5 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol), precipitated in ethanol, and dried in a vacuum oven at 65° C.

[0112] This reference shows a general procedure for the preparation of diene polymers. Copolymers of one or more conjugated dienes and one or more vinyl aromatic monomers, such as styrene, can be prepared in the same manner.

[0113] Example 1A (for comparison) An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 16 mmol n-butyllithium (as a 23 wt % solution in hexane) and stirred at 70° C. for 45 min. 2.56 mmol SiCl4 was added and stirred for 30 min. The polymer solution was quenched with 16 mmol n-octanol and stabilized with 7.5 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The solvent was removed by steam distillation and the polymer was dried in a vacuum oven at 65° C. The Mooney viscosity (ML(1+4) at 100° C.) was measured to be 83 MU.

[0114] Example 2 (for comparison) An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 14.25 mmol of n-butyllithium (as a 23 wt % solution in hexane) and stirred at 70° C. for 45 minutes. 7.125 mmol of 2,2-bis(2-tetrahydrofuryl)-propane was added to the living polymer solution and stirred for 5 minutes. 1.924 mmol of SiCl4 was added and stirred for 5 minutes. 8.55 mmol of octamethylcyclotetrasiloxane was added and stirred for 15 minutes. 8.55 mmol of 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexan-6-one was added. The polymer solution reaction mixture was stirred for 20 minutes, quenched (deactivated) with 14.25 mmol of n-octanol, and stabilized with 7.5 g of Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). 2 phr of stearic acid was added and the solvent was removed by steam distillation. The polymer was dried in a vacuum oven at 65°C.

[0115] Example 3 Example 1 was repeated except that 16 mmol of n-BuLi was used and the reaction was stirred for 45 minutes, after which 8 mmol of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added to the polymer solution and the polymer solution was stirred for an additional 20 minutes.

[0116] Example 4 An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene and 16 mmol n-butyllithium (as a 23 wt. % solution in hexane) and stirred at 70° C. for 45 minutes. 8 mmol 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added and stirred for 20 minutes. 8 mmol 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexan-6-one was added and the reaction mixture was stirred for an additional 20 minutes. The polymer solution was quenched with 16 mmol n-octanol and stabilized with 7.5 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The solvent was removed by steam distillation and the polymer was dried in a vacuum oven at 65° C.

[0117] Example 5 An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 15.7 mmol n-butyllithium (as a 23 wt. % solution in hexane) and stirred at 70° C. for 45 minutes. 15.7 mmol 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added to the polymer solution and the solution was stirred for 20 minutes. 15.7 mmol 2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane was added and the reaction mixture was stirred for an additional 20 minutes. The polymer solution was quenched with 16 mmol n-octanol and stabilized with 7.5 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The polymer was isolated and dried as described in Example 1.

[0118] Example 6 An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 14.25 mmol n-butyllithium (as a 23 wt % solution in hexane) and stirred for 60 minutes at 70° C. To this living polymer solution was added 7.125 mmol 2,2-bis(2-tetrahydrofuryl)-propane and stirred for 5 minutes. 14.25 mmol 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added and stirred for 15 minutes. 14.25 mmol 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexan-6-one was added and the reaction mixture was stirred for an additional 20 minutes. The polymer solution was quenched with 14.25 mmol of n-octanol and stabilized with 7.5 g of Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). After adding 2 phr (parts by weight per 100 parts by weight of resin) of stearic acid, the solvent was removed by steam distillation and the polymer was dried in a vacuum oven at 65° C.

[0119] Example 7 (outside the scope of claims) An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 15 mmol n-butyllithium (as a 23 wt % solution in hexane) and stirred at 70° C. for 60 minutes. 7.5 mmol 2,2-bis(2-tetrahydrofuryl)-propane was added to the living polymer solution and the reaction mixture was stirred for 5 minutes. 0.525 mmol octavinyl octasilsesquioxane (POSS-octavinyl substituted, Sigma Aldrich) was added and the reaction mixture was stirred for 5 minutes. 11 mmol octamethylcyclotetrasiloxane was added and stirred for 15 minutes. 11 mmol 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexan-6-one was added and the polymer solution was stirred for an additional 20 minutes. The polymer solution was quenched with 15 mmol of n-octanol and stabilized with 7.5 g of Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). Work-up was carried out as in Example 6.

[0120] Example 8 An inert 20 L reactor was charged with 8500 g hexane, 1500 g 1,3-butadiene, and 14.25 mmol n-butyllithium (as a 23 wt % solution in hexane) and stirred at 70° C. for 60 minutes. 7.125 mmol 2,2-bis(2-tetrahydrofuryl)-propane was added to the living polymer solution and stirred for 5 minutes. 1.14 mmol 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added and stirred for 5 minutes. 10.83 mmol octamethylcyclotetrasiloxane was added and stirred for 15 minutes. 10.83 mmol 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexan-6-one was added and the reaction mixture was stirred for an additional 20 minutes. The polymer solution was quenched with 14.25 mmol of n-octanol and stabilized with 7.5 g of Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). After adding 2 phr of stearic acid, the solvent was removed by steam distillation and the polymer was dried in a vacuum oven at 65° C.

[0121] [Table 1]

[0122] Examples 3-8 show that the unsaturated siloxanes according to the present disclosure can be used to prepare coupled polymers. Polymer coupling occurs, as demonstrated by the degree of coupling and low MSR values. The polymers prepared using the unsaturated siloxanes according to the present disclosure can also be reacted with various functionalizing reactants, as demonstrated by Examples 4-8.

[0123] Compound Research It is known that diene rubbers functionalized with polar functional groups can improve the dispersion of fillers in tire compounds. In tire compounds, rubber and fillers are the main components, and a good dispersion of fillers in the rubber matrix can ultimately result in improved tire properties. Rubber compounds containing functionalized diene rubbers are typically more difficult to process than their non-functionalized counterparts. It has been found that the polymers obtained using the unsaturated siloxane-based coupling agent according to the present disclosure can also be used to manufacture tire components, and can also obtain compounds with improved filler interaction.

[0124] Examples 9 to 16 Rubber compositions (Examples 9-16) containing the diene rubbers obtained in Examples 1, 1A, 2, 3, 6, 7, and 8 were prepared in a 1.5 L kneader using the ingredients shown in Table 3 and the mixing procedure (mixing protocol) shown in Table 2. The resulting compositions were vulcanized at 160° C. for 30 minutes. The properties of the vulcanizates are summarized in Tables 3 and 3A.

[0125] [Table 2]

[0126] [Table 3]

[0127] The above results show that the polymers obtained using the unsaturated siloxane according to the invention (Examples 11-13) have improved compound Mooney viscosity compared to the reference polymers 1 and 2 (Comparative Examples 9 and 10), which indicates better processability. Compared to the reference polymers, Examples 11-13 showed excellent filler dispersion, as shown by the improved Payne effect index (smaller [G'(0.5%)-G'(15%)]) and improved rolling resistance index (rebound 60°C, max tan δ, and tan δ at 60°C). The wet grip performance (tan δ at 0°C) was similar to that of the reference polymers.

[0128] [Table 4]

[0129] The results show improved properties of polymers modified with the siloxane coupling agent according to the present disclosure compared to the known coupling agent, SiCl4.

[0130] Example 16 (for comparison) A moisture-free, nitrogen-flushed reactor was charged with hexane, butadiene, styrene, and 22.9 mmol of DTHFP. The reaction mixture was heated to 33° C. and polymerized for 70 minutes after BuLi was added (T Max 72.8° C.). Octamethylcyclotetrasiloxane and tetrachlorosilane were added and reacted for 10 minutes at 70° C. 2,2-Dimethyl-[1,4,2]oxathiasilinan-6-one was added and reacted for 30 minutes. The reaction was then stopped and stabilized with IRGANOX 1520. The polymer was isolated by steam distillation and drying at 60° C. under reduced pressure.

[0131] Example 17 A moisture-free, nitrogen-flushed 20 L reactor was charged with 8500 g hexane, 165 g styrene, 1335 g butadiene, and 2.39 mmol DTHFP. The reaction mixture was heated to 47.5° C. and the adiabatic polymerization was started by adding 14 mmol BuLi and allowed to react for 60 minutes (T Max 70° C.). Then, 3.5 mmol 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was added and allowed to react for 10 minutes at 70° C. In the next step, 14 mmol 2,2-dimethyl-[1,4,2]oxathiasilinan-6-one was added and allowed to react for 10 minutes at 70° C. The reaction was stopped by adding 14 mmol 1-octanol and stabilized with Irganox 1520. The polymer was obtained by steam distillation of the polymer cement and drying at 60° C. under reduced pressure.

[0132] [Table 5]

[0133] A compound was prepared using the ingredients and amounts listed in Table 3, except that 100 phr of coupled polymer was used and no VSL 4526-2HM was used. The compound was prepared according to the protocol described above.

[0134] [Table 6]

[0135] The results shown in Table 5 show that the properties of styrene-butadiene copolymers are also improved by coupling with the coupling agent according to the present disclosure. The reduction in Mooney viscosity and G'(0.5%)-G'(15%) values ​​indicate easier processing and improved rubber-filler interaction (Payne effect). The rolling resistance index is also improved (increased rebound and reduced tan δ at 60°C). Wet grip properties are improved as shown by the increase in tan δ at 0°C.

Claims

1. A method for producing a polydiene rubber, comprising the steps of: (i) polymerizing at least one aliphatic conjugated diene monomer, preferably at least one aliphatic conjugated diene monomer having from 4 to 25 carbon atoms, to produce a polymer having reactive polymer chain ends; and (ii) reacting at least a portion of said reactive polymer chain ends with a coupling agent comprising 2 to 20 unsaturated siloxane units, preferably 3 to 15 units, more preferably 3 to 10 units, said coupling agent comprising a cyclic structure having at least two unsaturated siloxane units, but said coupling agent is not polycyclic.

2. The unsaturated siloxane units contain at least one alkenyl group, preferably vinyl (-CH=CH ２ ), allyl (-CH ２ -CH=CH ２ ), n-butenyl (-CH ２ CH ２ CH=CH ２ ), isobutenyl (-CH ２ (CH ３ )CH=CH ２ ), n-pentenyl (-CH ２ CH ２ CH ２ CH=CH ２ ), isopentenyl (-CH ２ (CH ３ ) CH ２ CH=CH ２ , -CH ２ CH ２ (CH ３ )CH=CH ２ 10. The method of claim 1, further comprising at least one alkenyl group selected from the group consisting of:

3. The unsaturated siloxane unit of the coupling agent has the following formula (1): 【Chemistry 1】 where R1 is alkenyl, preferably vinyl (-CH=CH ２ ), allyl (-CH ２ -CH=CH ２ ), n-butenyl (-CH ２ CH ２ CH=CH ２ ), isobutenyl (-CH ２ (CH ３ )CH=CH ２ ), n-pentenyl (-CH ２ CH ２ CH ２ CH=CH ２ ), isopentenyl (-CH ２ (CH ３ ) CH ２ CH=CH ２ , -CH ２ CH ２ (CH ３ )CH=CH ２ ), and each R2 independently represents H, OH, or an organic group, preferably an organic group having 1 to 20 carbon atoms and optionally having one or more heteroatoms selected from O, N, Si, S, and combinations thereof.

4. 4. The method of claim 3, wherein each R2 independently represents H, OH, alkenyl having 2 to 10 carbon atoms, alkyl having 1 to 10 carbon atoms, wherein the alkyl or alkenyl chain or both may be interrupted one or more times by ether oxygen atoms, or a siloxane or polysiloxane having up to 10 silicon atoms, wherein the siloxane or polysiloxane optionally has at least one silicon atom bearing at least one aliphatic substituent selected from an alkyl or alkenyl group or combinations thereof, and preferably at least one R2 is methyl, and more preferably all R2 groups are either methyl or ethyl, or combinations thereof.

5. The unsaturated siloxane unit of the coupling agent has the following formula (2): 【Chemistry 2】 wherein each R independently represents H, OH, or an organic group, preferably an organic group having 1 to 20 carbon atoms and, optionally, one or more heteroatoms selected from O, N, Si, S, and combinations thereof.

6. 6. The method of claim 5, wherein R represents H, OH, alkenyl having 2 to 10 carbon atoms, alkyl having 1 to 10 carbon atoms, wherein the alkyl or alkenyl chain or both may be interrupted once or more than once by ether oxygen atoms, or a siloxane or polysiloxane having up to 10 silicon atoms, wherein the siloxane or polysiloxane has at least one silicon atom optionally bearing at least one aliphatic substituent selected from an alkyl or alkenyl group or combinations thereof, preferably at least one R is methyl, more preferably all R groups are either methyl or ethyl or combinations thereof.

7. The method of any one of claims 1 to 6, wherein the coupling agent has a cyclic structure containing at least three unsaturated siloxane units.

8. The coupling agent has the following formula (3): 【Chemistry 3】 wherein n is an integer from 1 to 5, preferably from 1 to 3, R1 and R2 are as defined in claim 3 or 4, preferably R1 is vinyl and each R2 independently corresponds to １ -C ７ The process according to any one of claims 1 to 7, wherein the alkyl is selected from the group consisting of methyl, ...

9. The method according to any one of claims 1 to 9, wherein the coupling agent has a molecular weight of less than 5000 g / mol, preferably less than 2000 g / mol.

10. The method of any one of claims 1 to 10, wherein the conjugated diene monomer is 1,3-butadiene.

11. 11. The process according to any one of claims 1 to 10, wherein step (i) comprises copolymerising one or more copolymerisable vinyl aromatic comonomers, preferably selected from styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, para-tert-butylstyrene and combinations thereof.

12. 12. The method according to any one of claims 1 to 11, wherein the method comprises reacting, before, after or during step (ii), at least one functionalizing agent with the polymer to introduce at least one functional group into the polymer, the functional group having, in addition to C and H atoms, at least one heteroatom selected from Si, S, N, O and combinations thereof.

13. 13. The method of any one of claims 1 to 12, further comprising at least one of the steps of terminating the polymerization reaction, adding a stabilizer and / or oil, isolating the polymer, and forming the polymer into a bale, granules, or powder.

14. A polydiene rubber obtainable by the process according to any one of claims 1 to 13.

15. A curable composition comprising the polydiene rubber of claim 14, further comprising at least one vulcanizing agent for curing said polydiene rubber, preferably comprising said vulcanizing agent in an amount of 0.5 to 10 parts by weight per 100 parts by weight of diene rubber.

16. 16. A composition comprising a cured polydiene rubber obtained by curing the curable composition of claim 15, preferably an article, preferably an article selected from a tire or a tire tread.

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