Modified diene copolymers with targeted and stabilized viscosity

Abstract

To provide copolymers having a relatively high Mooney viscosity at the time of polymer desolventization while at the same time maintaining a relatively low aged Mooney viscosity.SOLUTION: A process for preparing a stabilized diene copolymer which is modified by reaction with an imine group-containing hydrocarbyloxysilane and subsequently stabilized with a hydrocarbyloxysilane.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Embodiments of the present invention are generally directed to modified diene copolymers having a targeted stabilized viscosity. In certain embodiments, the diene copolymer is modified by reaction with an imine group-containing hydrocarbyloxysilane and subsequently stabilized with the hydrocarbyloxysilane. [Background technology]

[0002] In the manufacture of tires, particularly tire treads, it is known to use modified polymers, such as those containing terminal functionalization. Rubber vulcanizates prepared with these modified polymers have been observed to exhibit reduced hysteresis loss and a reduced Payne effect, which is the loss of mechanical energy due to deagglomeration of fillers.

[0003] Polymer modification is often achieved by reacting a living polymer species with a compound capable of imparting functional groups to the ends of the polymer chain. For example, U.S. Patent No. 6,369,167 teaches preparing a diene polymer, such as a random copolymer of butadiene and styrene, by anionic polymerization techniques and then terminating the polymer with an imine-containing hydrocarbyloxysilane compound. The terminating compound, also referred to as a terminal modifier, is used in an amount of 0.25 to 3 moles per mole of the organolithium compound used to initiate the anionic polymerization.

[0004] A similar end-modifier is disclosed in U.S. Pat. No. 7,683,151, which teaches the use of 0.3 molar equivalents or more based on apparent active sites. Following the modification reaction, this patent teaches the addition of a condensation promoter (e.g., tin carboxylate) to condense the hydrocarbyloxysilane residues at the polymer chain ends (causing polymer coupling). After finishing, the resulting modified polymer has a Mooney viscosity (ML at 100°C) of 10 to 150. 1+4 )

[0005] Hydrocarbyloxysilane residues have been found to increase Mooney viscosity after aging, and this increase is believed to be due to coupling between functional polymers in the presence of water. This coupling is believed to be initiated when water hydrolyzes the hydrocarbyloxysilane substituents to form siloxy substituents, which then condense and couple together on the siloxy substituents of each polymer. U.S. Pat. No. 6,255,404 teaches a solution to this increase in Mooney viscosity by treating the modified polymer with an alkylalkoxysilane (e.g., octyltriethoxysilane), thereby stabilizing the hydrocarbyloxysilane end groups. The alkylalkoxysilane may be added in an amount of 1 to 20 moles per mole of initiator; however, if present in an amount greater than the equivalent of the alkoxysilane functionality, a decrease in polymer viscosity is observed due to the plasticizing effect of the alkylalkoxysilane (i.e., the excess alkylalkoxysilane acts as an oil). Summary of the Invention

[0006] One or more embodiments of the present invention provide a process for preparing a stabilized diene copolymer having a terminal modification, comprising: (i) combining an organolithium compound, butadiene monomer, and styrene monomer, optionally together with a vinyl modifier, in a solvent to form a polymerization mixture; (ii) polymerizing the monomers, thereby forming a living polymer; and (iii) after polymerizing the monomers, introducing an imine-containing hydrocarbyloxysilane compound into the polymerization mixture, wherein the imine-containing hydrocarbyloxysilane is introduced in an amount of about 0.2 to 0.8 moles per mole of organolithium compound. (iv) after the step of introducing the imine-containing hydrocarbyloxysilane, introducing a hydrocarbyl hydrocarbyloxysilane to the polymerization mixture containing the modified polymer, thereby forming a stabilized polymerization mixture, wherein the hydrocarbyl hydrocarbyloxysilane is added in an amount of from about 1 to about 12 moles per mole of organolithium compound; and (v) desolventizing the polymer mixture to provide a stabilized diene copolymer having terminal modifications. DETAILED DESCRIPTION OF THE INVENTION

[0007] Embodiments of the present invention are based, at least in part, on the discovery of a process for producing diene-based copolymers modified with imine-containing hydrocarbyloxysilane compounds and stabilized with hydrocarbylhydrocarbyloxysilane compounds. While the prior art generally discusses polymers of this nature, the present invention is based on the desire to achieve a polymer with a relatively high initial viscosity (i.e., upon polymer desolventization) that allows for efficient handling during the polymer's manufacture, and a relatively low viscosity after aging (i.e., without significant Mooney increase) that allows for efficient use of the polymer in the manufacture of rubber articles such as tires. In one or more embodiments, the diene-based copolymers produced in accordance with the present invention are modified copolymers of butadiene and styrene that have a Mooney viscosity (ML at 100°C) of greater than 50 prior to isolation of the modified copolymer. 1+4 ) and an aged Mooney viscosity (ML at 100°C) of less than 120 1+4 ). While the prior art has discussed diene-based copolymers terminated with imine-containing trialkoxysilanes and the use of alkyltrioxysilanes to stabilize similar polymers against excessive Mooney growth, the prior art lacks an understanding of all of the factors that significantly affect important polymer properties such as Mooney viscosity and the interactions between these factors. In particular, it has been unexpectedly discovered that the viscosity (i.e., Mooney viscosity) of a polymer, from initial synthesis through long-term aging, depends on factors such as peak molecular weight, amount of modifier, amount of stabilizer, coupling efficiency, and amount of condensation catalyst. These discoveries make it possible to obtain copolymers that have a relatively high Mooney viscosity upon polymer desolventization while maintaining a relatively low Mooney viscosity after aging. Process Overview

[0008] In one or more embodiments, the process for forming a polymer according to the present invention generally comprises (i) a polymerization step to form a reactive polymer, (ii) a subsequent modification step to functionalize the reactive polymer, (iii) a stabilization step to stabilize the functionalized polymer, and (iv) a polymer desolventization step to isolate the stabilized functionalized polymer. In one or more embodiments, the process may further comprise a hydrolysis and / or condensation step. In these or other embodiments, the process may further comprise a polymer drying step to remove water from the polymer product.

[0009] polymerization In one or more embodiments, the polymerizing step comprises anionically polymerizing a conjugated diene monomer (e.g., butadiene) and a vinyl aromatic monomer (e.g., styrene) in solution to provide a polymerization mixture comprising a polymer having reactive polymer chain ends.

[0010] The preparation of polymers using anionic polymerization techniques is generally known. The important mechanistic features of anionic polymerization are described in books (e.g., Hsieh, HL; Quirk, RP; Anionic Polymerization: Principles and Practical Applications; Marcel Dekker: New York, 1996) and reviews (e.g., Hadjichristidis, N.; Pitsikalis, M.; Pispas, S.; Iatrou, H.; Chem. Rev. 2001, 101(12), 3747-3792). Anionic initiators can advantageously produce polymers with reactive chain ends (e.g., living polymers) that can react with additional monomers for further chain growth or with specific functionalizing agents to give functionalized polymers before quenching. Polymers with reactive polymer chain ends are sometimes simply referred to as reactive polymers. As will be appreciated by those skilled in the art, these reactive polymers contain reactive chain ends, which are believed to be ionic, at which a reaction between a functionalizing agent and the reactive chain end of the polymer can occur, thereby imparting functionality or functional groups to the polymer chain end or coupling multiple polymers together.

[0011] Monomers that can be anionically polymerized to form these polymers include conjugated diene monomers, which can optionally be copolymerized with other monomers, such as vinyl-substituted aromatic monomers. Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, and 2,4-hexadiene. Mixtures of two or more conjugated dienes can also be used in copolymerization. Examples of monomers copolymerizable with conjugated diene monomers include vinyl-substituted aromatic compounds, such as styrene, p-methylstyrene, α-methylstyrene, and vinylnaphthalene.

[0012] The practice of the present invention is not limited by the selection of any particular anionic initiator. Exemplary anionic initiators include organolithium compounds. In one or more embodiments, the organolithium compound may include a heteroatom. In these or other embodiments, the organolithium compound may include one or more heterocyclic groups. Types of organolithium compounds include alkyllithium compounds, aryllithium compounds, and cycloalkyllithium compounds. Specific examples of organolithium compounds include ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, n-amyllithium, isoamyllithium, and phenyllithium. Still other anionic initiators include organosodium compounds, such as phenylsodium and 2,4,6-trimethylphenylsodium.

[0013] Anionic polymerizations may be carried out in polar solvents, non-polar solvents, and mixtures thereof. In one or more embodiments, a solvent may be used as a carrier to dissolve or suspend the initiator, facilitating delivery of the initiator to the polymerization system.

[0014] In one or more embodiments, suitable solvents include organic compounds that do not undergo polymerization or incorporation into the propagating polymer chain during polymerization of monomers in the presence of a catalyst. In one or more embodiments, these organic species are liquid at ambient temperature and pressure. In one or more embodiments, these organic solvents are inert to the catalyst. Exemplary organic solvents include hydrocarbons with low or relatively low boiling points, such as aromatic hydrocarbons, aliphatic hydrocarbons, and cycloaliphatic hydrocarbons. Non-limiting examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, diethylbenzene, and mesitylene. Non-limiting examples of aliphatic hydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, isopentane, isohexane, isopentane, isooctane, 2,2-dimethylbutane, petroleum ether, kerosene, and mineral spirits. Non-limiting examples of cycloaliphatic hydrocarbons include cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane. Mixtures of the above hydrocarbons can also be used. The low-boiling hydrocarbon solvent is typically separated from the polymer when the polymerization is complete. Other examples of organic solvents include high-molecular-weight, high-boiling hydrocarbons, such as paraffinic oil, aromatic oil, or other hydrocarbon oils commonly used in oil-extending polymers. Because these hydrocarbons are non-volatile, they typically do not need to be separated and remain entrapped within the polymer.

[0015] Anionic polymerization may be carried out in the presence of a randomizer (sometimes referred to as a polar coordinator) or vinyl modifier. As will be appreciated by those skilled in the art, these compounds can serve dual roles: they can assist in the randomization of comonomers throughout the polymer chain and / or they can adjust the vinyl content of diene-derived mer units. Compounds useful as randomizers include those containing oxygen or nitrogen heteroatoms and non-bonding electron pairs. Examples include linear and cyclic oligomeric oxolanyl alkanes; dialkyl ethers of mono- and oligoalkylene glycols (also known as glyme ethers); "crown" ethers; tertiary amines; linear THF oligomers; and the like. Linear and cyclic oligomeric oxolanyl alkanes are described in U.S. Pat. Nos. 4,429,091 and 9,868,795, which are incorporated herein by reference. Specific examples of compounds useful as randomizers include 2,2-bis(2'-tetrahydrofuryl)propane, 1,2-dimethoxyethane, N,N,N',N'-tetramethylethylenediamine (TMEDA), tetrahydrofuran (THF), 1,2-dipiperidylethane, dipiperidylmethane, hexamethylphosphoramide, N-N'-dimethylpiperazine, diazabicyclooctane, dimethyl ether, diethyl ether, tri-n-butylamine, and mixtures thereof. In other embodiments, potassium alkoxides can be used to randomize the styrene distribution.

[0016] The amount of randomizer to be used may depend on various factors (e.g., the desired polymer microstructure, the ratio of monomer to comonomer, the polymerization temperature, and the nature of the particular randomizer used. In one or more embodiments, the amount of randomizer used may range from 0.01 to 100 moles per mole of anionic initiator.

[0017] The anionic initiator and randomizer can be introduced into the polymerization system by a variety of methods. In one or more embodiments, the anionic initiator and randomizer can be added separately to the monomers to be polymerized, either stepwise or simultaneously.

[0018] As described above, reactive polymers are produced by polymerizing a conjugated diene monomer together with a monomer copolymerizable with the conjugated diene monomer in the presence of an effective amount of an initiator. The introduction of the initiator, conjugated diene monomer, comonomer, and solvent forms a polymerization mixture in which the reactive polymer is formed. Polymerization in a solvent produces a polymerization mixture in which the polymer product is dissolved or suspended in the solvent. This polymerization mixture is sometimes referred to as a polymer cement.

[0019] The amount of initiator to be used may depend on the interplay of various factors (e.g., the type of initiator used, the purity of the components, the polymerization temperature, the desired polymerization rate and conversion, the desired molecular weight, and many other factors). In one or more embodiments, the amount of initiator used may be expressed as millimoles of initiator per weight of monomer. In one or more embodiments, the initiator loading may vary from about 0.05 to about 50 millimoles, in other embodiments from about 0.1 to about 25 millimoles, in yet other embodiments from about 0.2 to about 2.5 millimoles, and in other embodiments from about 0.4 to about 0.7 millimoles of initiator per 100 grams of monomer.

[0020] In one or more embodiments, the polymerization may be carried out in any conventional polymerization vessel known in the art. For example, the polymerization may be carried out in a conventional stirred tank reactor. In one or more embodiments, all of the components used for the polymerization may be combined in a single vessel (e.g., a conventional stirred tank reactor), and all steps of the polymerization process may be carried out in this vessel. In other embodiments, two or more components may be pre-combined in one vessel and then transferred to another vessel where the monomer (or at least a majority thereof) is polymerized. Because various embodiments of the present invention involve the use of multiple reactors or reaction zones, the vessel in which the polymerization takes place (e.g., a tank reactor) may be referred to as the first vessel or first reaction zone.

[0021] The polymerization can be carried out as a batch process, a continuous process, or a semi-continuous process. In a semi-continuous process, monomer is intermittently charged as needed to replace already polymerized monomer. In one or more embodiments, the conditions under which the polymerization proceeds may be controlled to maintain the temperature of the polymerization mixture within a range of about -10°C to about 200°C, in other embodiments about 0°C to about 150°C, and in other embodiments about 20°C to about 110°C. In one or more embodiments, the heat of polymerization may be removed by external cooling through a thermally controlled reactor jacket, internal cooling by vaporizing and condensing the monomer using a reflux condenser connected to the reactor, or a combination of the two methods. The polymerization conditions may also be controlled to carry out the polymerization under pressures of about 0.1 atm to 50 atm, in other embodiments about 0.5 atm to about 20 atm, and in other embodiments about 1 atm to about 10 atm. In one or more embodiments, pressures at which the polymerization may be carried out include those that ensure that the majority of the monomer is in the liquid phase. In these or other embodiments, the polymerization mixture may be maintained under anaerobic conditions. Polymer properties before modification

[0022] As explained above, in certain embodiments of the present invention, the reactive polymer produced is a copolymer of styrene and butadiene. In one or more embodiments, the copolymer is random and optionally contains styrene or butadiene microblocks (i.e., 3 to 10 repeating styrene or butadiene units). In one or more embodiments, the copolymer is free or substantially free of styrene or butadiene chemical blocks (i.e., more than 10 repeating styrene or butadiene units). In one or more embodiments, the reactive copolymer can be characterized by its styrene content, which is the weight percent of styrene mer units relative to the total weight of the reactive copolymer before modification. As will be understood by those skilled in the art, this can be determined from the weight of charged styrene monomer relative to the total weight of charged monomers (i.e., the total weight of charged butadiene and styrene). In one or more embodiments, the reactive polymer contains greater than 5 weight percent, in other embodiments greater than 7 weight percent, and in other embodiments greater than 9 weight percent styrene, prior to modification. In these or other embodiments, the reactive polymer comprises less than 45 weight percent styrene, in other embodiments less than 30 weight percent, in other embodiments less than 16 weight percent, in other embodiments less than 14 weight percent, and in other embodiments less than 12 weight percent styrene. In one or more embodiments, the polymer comprises from about 5 to about 45 weight percent, in other embodiments from about 7 to about 14 weight percent, and in other embodiments from about 9 to about 12 weight percent styrene.

[0023] In one or more embodiments, reactive polymers produced according to aspects of the present invention can be characterized by their vinyl content, which can be described as the number of unsaturations in 1,2 microstructures relative to the total unsaturation in the polymer chain. As will be appreciated by those skilled in the art, vinyl content can be determined by FTIR analysis. In one or more embodiments, the reactive polymer contains greater than 10% by weight, greater than 20% by weight in other embodiments, and greater than 35% by weight in other embodiments. In these or other embodiments, the reactive polymer contains less than 80% by weight, less than 60% by weight in other embodiments, and less than 46% by weight in other embodiments. In one or more embodiments, the reactive polymer contains from about 10 to about 80% by weight, from about 20 to about 60% by weight in other embodiments, and from about 35 to about 46% by weight in other embodiments.

[0024] In one or more embodiments, the reactive polymer may also be characterized by its peak molecular weight (Mp). As will be appreciated by those skilled in the art, Mp can be determined by gel permeation chromatography (GPC) using appropriate calibration standards. For purposes of this specification, GPC measurements use polystyrene standards and polystyrene Mark-Hwink constants unless otherwise specified. In one or more embodiments, the reactive polymer has an Mp greater than 160 kg / mol, in other embodiments greater than 170 kg / mol, and in other embodiments greater than 180 kg / mol, which may also be referred to as the base Mp. In these or other embodiments, the reactive polymer has an Mp less than 280 kg / mol, in other embodiments less than 260 kg / mol, and in other embodiments less than 250 kg / mol. In one or more embodiments, the reactive polymer has an Mp of from about 160 to about 280 kg / mol, in other embodiments from about 170 to about 260 kg / mol, and in other embodiments from about 180 to about 250 kg / mol.

[0025] In one or more embodiments, at least about 30% of the polymer molecules contain living ends, in other embodiments at least about 50% of the polymer molecules contain living ends, and in other embodiments at least about 80% contain living ends. Polymer Modification

[0026] As described above, after polymerization, the reactive polymer undergoes modification. That is, the reactive ends of the polymer are modified, sometimes referred to as functionalization, by introducing an imine-containing hydrocarbyloxysilane compound into the polymerization mixture. It is believed that the polymer chain ends react with the imine-containing hydrocarbyloxysilane (which for purposes of this specification may also be referred to as a functionalizing agent or a modifying agent) to provide residues of the functionalizing agent at the polymer chain ends. Thus, the reaction between the polymer and the functionalizing agent produces a polymer composition comprising one or more polymer chains comprising a terminal group derived from the imine-containing hydrocarbyloxysilane. In one or more embodiments, greater than 10 mol%, in other embodiments greater than 30 mol%, and in other embodiments greater than 35 mol% of the polymer chains in the polymer composition comprise a terminal functional group. In these or other embodiments, less than 80 mol%, in other embodiments less than 70 mol%, and in other embodiments less than 65 mol% of the polymer chains in the polymer composition comprise a terminal functional group. In one or more embodiments, about 10 to about 80 mole percent, in other embodiments about 30 to about 70 mole percent, and in other embodiments about 35 to about 65 mole percent of the polymer chains in the polymer composition comprise a functional end group. These polymers may also be referred to as functionalized or modified polymers. It is understood that polymer coupling may also result from the reaction between a functionalizing agent and a reactive polymer. In either case, both polymers having functional chain end groups and polymers coupled with the residue of a functionalizing agent are referred to as modified or functionalized polymers, unless otherwise specified.

[0027] In one or more embodiments, the imine-containing hydrocarbyloxysilane can include N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine, or N-(4-N,N-dimethylaminobenzylidene)-3-(triethoxysilyl)-1-propanamine. In certain embodiments, the imine-containing hydrocarbyloxysilane is N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine or N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine.

[0028] The amount of functionalizing agent (i.e., imine-containing hydrocarbyloxysilane) used in the practice of the present invention can be described in terms of the lithium or metal cation relative to the initiator. In one or more embodiments, the amount of functionalizing agent introduced into the polymerization mixture is greater than 0.2 moles, in other embodiments greater than 0.3 moles, and in other embodiments greater than 0.4 moles, of functionalizing agent per mole of lithium in the initiator. In these or other embodiments, less than 0.8 moles, in other embodiments less than 0.7 moles, and in other embodiments less than 0.65 moles of functionalizing agent per mole of lithium are introduced into the polymerization mixture. In one or more embodiments, from about 0.2 to about 0.8 moles, in other embodiments from about 0.3 to about 0.7 moles, and in other embodiments from about 0.4 to about 0.65 moles of functionalizing agent per mole of lithium are introduced into the polymerization mixture.

[0029] In one or more embodiments, the functionalizing agent is introduced into the polymer cement while the polymer is dissolved or suspended in the solvent. As will be understood by those skilled in the art, this solution may also be referred to as the polymer cement. In one or more embodiments, the characteristics of the polymer cement, such as its concentration, are the same or similar to the characteristics of the cement prior to functionalization. In other embodiments, the stabilizing agent may be introduced into the polymer while the polymer is suspended or dissolved in the monomer.

[0030] In one or more embodiments, the polymer modification (i.e., the introduction of the functionalizing agent into the polymer cement) occurs in the same vessel in which the polymerization occurs. In other embodiments, the polymer modification occurs outside of the reaction vessel in which the polymerization occurs. For example, the functionalizing agent can be introduced into the polymerization mixture (i.e., the polymer cement) in a downstream vessel or downstream transfer conduit.

[0031] In one or more embodiments, the reaction between the functionalizing agent and the reactive polymer may occur at a temperature of from about 10° C. to about 150° C., and in other embodiments, from about 20° C. to about 110° C. The time required for the reaction between the functionalizing agent and the reactive polymer to be complete depends on various factors, including the type and amount of catalyst or initiator used in preparing the reactive polymer, the type and amount of functionalizing agent, and the temperature at which the functionalization reaction is carried out. In one or more embodiments, the reaction between the functionalizing agent and the reactive polymer may occur for a period of from about 30 seconds to about 90 minutes, or in other embodiments, from 10 to 60 minutes. Polymer Stabilization

[0032] As described above, after modification, the modified polymer is stabilized by introducing an alkylhydrocarbyloxysilane into the polymerization mixture containing the modified polymer. The alkylhydrocarbyloxysilane is believed to react with the terminal functional group. The reaction between the chain end functional group and the alkylhydrocarbyloxysilane is believed to occur either upon introduction of the two molecules or after aging of the composition. The reaction between the alkylhydrocarbyloxysilane and the terminal group produces a polymer composition containing one or more polymer chains containing terminal groups derived from the imine-containing hydrocarbyloxysilane and subsequent reaction with the alkylhydrocarbyloxysilane.

[0033] In one or more embodiments, the stabilizer is a hydrocarbylhydrocarbyloxysilane which can be defined by Formula I: [ka] (In the formula, R 2 is a hydrocarbyl group, and R 3 , R 4 , and R 5 are each independently a hydrocarbyl group or a hydrocarbyloxy group. 3 , R 4 , and R 5 is a hydrocarbyl group. In other embodiments, R 3 and R 4 is a hydrocarbyl group, and R 5 is a hydrocarbyloxy group. In other embodiments, R 3 is a hydrocarbyl group, and R 4 and R 5 is a hydrocarbyloxy group. In certain embodiments, R 3 , R 4 , and R 5 are all hydrocarbyloxy groups.

[0034] In one or more embodiments, the hydrocarbyl group of the hydrocarbyl hydrocarbyloxysilane may include, but is not limited to, an alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an alkenyl group, a cycloalkenyl group, a substituted cycloalkenyl group, an aryl group, an aryl group, a substituted aryl group, an aralkyl group, an alkaryl group, or an alkynyl group. Substituted hydrocarbyl groups include hydrocarbyl groups in which one or more hydrogen atoms have been replaced with a substituent such as an alkyl group. In one or more embodiments, the hydrocarbyl group may contain from one or the minimum number of carbon atoms appropriate for forming the group up to 20 carbon atoms. These hydrocarbyl groups may contain heteroatoms such as, but not limited to, nitrogen, boron, oxygen, silicon, sulfur, and phosphorus atoms.

[0035] In one or more embodiments, the hydrocarbyloxy group of the hydrocarbyl hydrocarbyloxy silane includes, but is not limited to, an alkoxy group, a cycloalkoxy group, a substituted cycloalkoxy group, an alkenyloxy group, a cycloalkenyloxy group, a substituted cycloalkenyloxy group, an aryloxy group, an allyloxy group, a substituted aryloxy group, an aralkyloxy group, an alkaryloxy group, or an alkynyloxy group. Substituted hydrocarbyloxy groups include hydrocarbyloxy groups in which one or more hydrogen atoms bonded to a carbon atom have been replaced with a substituent such as an alkyl group. In one or more embodiments, the hydrocarbyloxy group may contain from one or the minimum number of carbon atoms appropriate for forming the group up to 20 carbon atoms. The hydrocarbyloxy group may contain heteroatoms such as, but not limited to, nitrogen, boron, oxygen, silicon, sulfur, and phosphorus atoms.

[0036] In one or more embodiments, types of hydrocarbyl hydrocarbyloxy silanes include trihydrocarbyl hydrocarbyloxy silanes, dihydrocarbyl dihydrocarbyloxy silanes, hydrocarbyl trihydrocarbyloxy silanes, and tetrahydrocarbyloxy silanes.

[0037] Specific examples of hydrocarbyl hydrocarbyloxysilanes include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, phenyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, phenyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, methyltriphenoxysilane, ethyltriphenoxysilane, propyltriphenoxysilane, octyltriphenoxysilane, Phenyltriphenoxysilane, Decyltriphenoxysilane, Methyldiethoxymethoxysilane, Ethyldiethoxymethoxysilane, Propyldiethoxymethoxysilane, Phenyldiethoxymethoxysilane, Octyldiethoxymethoxysilane, Decyldiethoxymethoxysilane, Methyldiphenoxymethoxysilane, Ethyldiphenoxymethoxysilane, Propyldiphenoxymethoxysilane, Phenyldiphenoxymethoxysilane, Octyldiphenoxymethoxysilane, Decyldiphenoxymethoxysilane, Methyldimethoxyethoxysilane, Ethyl Tyldimethoxyethoxysilane, Propyldimethoxyethoxysilane, Phenyldimethoxyethoxysilane, Octyldimethoxyethoxysilane, Decyldimethoxyethoxysilane, Methyldiphenoxyethoxysilane, Ethyldiphenoxyethoxysilane, Propyldiphenoxyethoxysilane, Phenyldiphenoxyethoxysilane, Octyldiphenoxyethoxysilane, Decyldiphenoxyethoxysilane, Methyldimethoxyphenoxysilane, Ethyldimethoxyphenoxysilane, Propyldimethoxyphenoxysilane, Phenyldimethoxyphenoxy hydroxysilane, octyldimethoxyphenoxysilane, decyldimethoxyphenoxysilane, methyldiethoxyphenoxysilane, ethyldiethoxyphenoxysilane, propyldiethoxyphenoxysilane, phenyldiethoxyphenoxysilane, octyldiethoxyphenoxysilane, decyldiethoxyphenoxysilane, methylmethoxyethoxyphenoxysilane, ethylmethoxyethoxyphenoxysilane, propylmethoxyethoxyphenoxysilane, phenylmethoxyethoxyphenoxysilane, octylmethoxyethoxyphenoxysilane,and decyl methoxy ethoxy phenoxy silane.

[0038] In one or more embodiments, the stabilizing agent is added to the polymer cement after sufficient time has been provided to complete the reaction between the reactive polymer and the functionalizing agent, hi one or more embodiments, the stabilizing agent is added to the polymer cement 30 minutes, in other embodiments 15 minutes, and in other embodiments 10 minutes after the time the functionalizing agent is introduced to the polymer cement.

[0039] The amount of stabilizer (i.e., hydrocarbyl hydrocarbyloxysilane) used in the practice of the present invention can be described in terms of moles of lithium relative to the initiator. In one or more embodiments, more than 1 mole, in other embodiments more than 2 moles, in other embodiments more than 3 moles, and in other embodiments more than 4 moles of functionalizing agent are introduced into the polymerization mixture per mole of lithium in the initiator. In these or other embodiments, less than 12 moles, in other embodiments less than 11 moles, in other embodiments less than 10 moles, in other embodiments less than 9 moles, and in other embodiments less than 8 moles of functionalizing agent are introduced into the polymerization mixture per mole of lithium. In one or more embodiments, from about 1 to about 12 moles, in other embodiments from about 3 to about 10 moles, and in other embodiments from about 4 to about 8 moles of functionalizing agent are introduced into the polymerization mixture per mole of lithium.

[0040] In one or more embodiments, stabilization of the polymer (i.e., introduction of the stabilizer) occurs in the same vessel in which polymerization occurred. In these embodiments, this includes the same vessel in which modification occurred. In other embodiments, stabilization of the polymer (i.e., introduction of the stabilizer) occurs outside the vessel in which polymerization occurred. Similarly, in one or more embodiments, stabilization of the polymer occurs outside the vessel in which polymer modification occurred. For example, in one or more embodiments, the stabilizer can be added to the polymerization mixture (i.e., polymer cement) in a vessel or transfer line downstream from the vessel in which polymerization occurred and downstream from the vessel in which polymer modification occurred. For purposes of this specification, the vessel or conduit into which the stabilizer is introduced relative to the polymerization vessel may also be referred to as a second vessel or second reaction zone. Condensation accelerator

[0041] In one or more embodiments, a condensation promoter may be added to the polymerization mixture after the functionalizing agent has been introduced into the reactive polymer, optionally after the addition of a quenching agent and / or antioxidant, optionally after or together with the stabilizer, and optionally after recovery or isolation of the functionalized polymer. Useful condensation promoters include tin and / or titanium carboxylates and tin and / or titanium alkoxides. One specific example is titanium 2-ethylhexyl oxide. Useful condensation catalysts and their uses are disclosed in U.S. Patent Application Publication No. 2005 / 0159554 (U.S. Patent No. 7,683,151), which is incorporated herein by reference. In other embodiments, organic acids can be used as condensation promoters. Useful types of organic acids include aliphatic, alicyclic, and aromatic monocarboxylic, dicarboxylic, tricarboxylic, and tetracarboxylic acids. Specific examples of useful organic acids include, but are not limited to, acetic acid, propionic acid, butyric acid, hexanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, cyclohexanoic acid, and benzoic acid.

[0042] The amount of condensation promoter used in the practice of the present invention can be described in terms of moles of lithium relative to the initiator. In one or more embodiments, the amount of condensation promoter per mole of lithium is greater than 1.0 mole, in other embodiments greater than 1.5 moles, and in other embodiments greater than 1.8 moles of condensation promoter per mole of lithium in the initiator. In these or other embodiments, less than 4.0 moles, in other embodiments less than 3.3 moles, and in other embodiments less than 3.0 moles of condensation promoter per mole of lithium are introduced into the polymerization mixture. In one or more embodiments, from about 1.0 to about 4.0 moles, in other embodiments from about 1.5 to about 3.3 moles, and in other embodiments from about 1.8 to about 3.0 moles of condensation promoter per mole of lithium are introduced into the polymerization mixture. antioxidants

[0043] In one or more embodiments, an antioxidant may be added to the polymerization mixture after the functionalizing agent has been introduced into the reactive polymer, optionally after the addition of a quenching agent and / or antioxidant, optionally after or together with the stabilizer, and optionally after recovery or isolation of the functionalized polymer. An exemplary antioxidant includes 2,6-di-tert-butyl-4-methylphenol.

[0044] In one or more embodiments, processing aids and other optional additives, such as oils, may be added to the polymer cement after the polymer is formed. Optional Quenching

[0045] In one or more embodiments, after the reaction between the reactive polymer and the functionalizing agent is achieved or completed, a quenching agent may be added to the polymerization mixture to deactivate any remaining reactive polymer chains and catalyst or catalyst components. The quenching agent may include a protic compound, including, but not limited to, an alcohol, a carboxylic acid, an inorganic acid, water, or a mixture thereof. The amount of quenching agent used may range from 0.5 to 10 moles of quenching agent per mole of lithium used to initiate the polymerization. Polymer properties after desolvation

[0046] As mentioned above, the polymers of the present invention can be subjected to a desolventization process as described herein below to produce a Mooney viscosity (ML at 100° C.) of greater than 50, in other embodiments greater than 52, and in other embodiments greater than 55. 1+4 In one or more embodiments, the polymers of the present invention are characterized by a Mooney viscosity (ML at 100°C) of about 50 to about 105, in other embodiments about 52 to about 80, and in other embodiments about 55 to about 70, during the desolvation process. 1+4 For purposes of this specification, unless otherwise specified, Mooney viscosity (ML at 100°C) 1+4 ) is determined according to ASTM D 1648-17.

[0047] Additionally, in one or more embodiments, the polymers of the present invention are characterized by a coupling rate during the desolvation step of greater than 20 percent, greater than 30 percent in other embodiments, and greater than 40 percent in other embodiments. In these or other embodiments, the polymers of the present invention are characterized by a coupling rate during the desolvation step of less than 80 percent, less than 70 percent in other embodiments, and less than 65 percent in other embodiments. In one or more embodiments, the polymers of the present invention are characterized by a coupling rate during the desolvation step of about 20 to about 80 percent, about 30 to about 70 percent in other embodiments, and about 40 to about 65 percent. As will be understood by those skilled in the art, coupling rates can be determined by GPC. For purposes herein, coupling refers to the area percentage of the GPC curve with peaks that are at least twice the base peak (i.e., the coupling rate is B / (A+B)·100%, where A is the area of ​​the base peak and B is the total area of ​​all peaks that are at least twice the base peak (i.e., A)).

[0048] In one or more embodiments, the method of the present invention includes selecting from the ranges disclosed herein (i) the peak molecular weight of the base polymer, (ii) the desired loading of functionalizing agent, and (iii) an appropriate loading of stabilizer, and (iv) an appropriate loading of condensation catalyst to meet a target Mooney viscosity (e.g., greater than 50) upon desolventization within the range of the following formula: Mooney viscosity after desolvation = 44.7 + [0.5218 base Mp] - [5.1 functionalizing agent equivalents] - [4.765 stabilizer equivalents] + [8.86 condensation accelerator equivalents] (In the formula, Mooney viscosity at the time of desolvation is ML at 100°C at the time of desolvation.) 1+4 where Base Mp represents the peak molecular weight (kg / mol) of the base polymer as determined by GPC using polystyrene standards and the polystyrene Mark-Hwink constant, Functionalizing Agent Equivalent is the number of moles of functionalizing agent per mole of lithium used to initiate polymerization of the polymer, Stabilizing Agent Equivalent is the number of moles of stabilizer per mole of lithium used to stabilize the polymer, and Condensation Promoter Equivalent is the number of moles of condensation catalyst per mole of lithium used to promote condensation.

[0049] In one or more embodiments, the above equation for Mooney viscosity upon desolvation is satisfied when the Mooney viscosity is 50 or greater (or other ranges disclosed herein), the Mp is about 160 to about 180 kg / mol, the functionalizing agent equivalent is about 0.2 to about 0.8 moles of functionalizing agent per mole of lithium, the stabilizer equivalent is about 1 to about 12 moles of stabilizer per mole of lithium, and the condensation promoter equivalent is about 1 to about 4 moles per mole of lithium. As will be appreciated by those of skill in the art, the above equation may also be satisfied in other ranges disclosed herein (e.g., other ranges of functionalizing agent equivalents). Desolvation of polymers

[0050] After stabilization, as described above, and optionally after the introduction of a condensation promoter and / or antioxidant, the polymer product (i.e., the stabilized functionalized polymer) is subjected to desolventization. In other words, the polymer is synthesized in an organic solvent, as described above, and the organic solvent is separated from the polymer during the desolventization step.

[0051] In certain embodiments, desolventization involves hot water and / or steam coagulation. For example, the polymerization mixture containing the stabilized modified polymer may be combined with steam or a hot water stream. The heat associated with the steam or hot water stream volatilizes the solvent and any unreacted monomers. The polymer product is then dispersed in the aqueous phase, for example, in the form of polymer crumbs. The nature and size of the polymer crumbs can generally be manipulated by introducing mechanical energy in the form of a mixer.

[0052] In one or more embodiments, the polymer crumbs are temporarily stored in water as a crumb dispersion until the subsequent drying step described below. The crumb dispersion is generally a mixture of polymer particles or crumbs and water. The polymer particles, sometimes referred to as coagulated polymer, are generally macroscale and have dimensions greater than at least 1 mm. This crumb dispersion can be contained in a vessel, such as a conventional reactor vessel, such as a continuous stirred tank reactor.

[0053] In one or more embodiments, the polymer crumbs can be further processed to remove residual solvent and dry the polymer (i.e., separate the polymer from the water). In the practice of the present invention, the polymer can be dried using conventional techniques, which can include one or more of filtration, squeezing, and heating. After desolventization and drying, the volatile content of the dried polymer can be less than 2.0% by weight of the polymer, in other embodiments less than 1.0% by weight, and in other embodiments less than 0.5% by weight.

[0054] In other embodiments, the polymer product may be desolventized by using a devolatilizer, which is an extruder-type device that may operate in conjunction with heat and / or vacuum. In yet other embodiments, the polymerization mixture may be directly drum dried.

[0055] Regardless of the method used to desolventize and dry the polymer, the finished polymer product may be referred to as a dried polymer. The dried polymer may be shaped or otherwise manipulated into bales using conventional techniques. Polymer properties of dry polymer

[0056] In one or more embodiments, the dried, unaged polymers of the present invention have advantageous Mooney viscosities (ML at 100° C.). 1+4 Specifically, in one or more embodiments, the polymer has a Mooney viscosity (ML at 100° C.) of less than 95, in other embodiments less than 90, and in other embodiments less than 85, within 24 hours of desolventization and drying. 1+4 In these or other embodiments, the polymer has a Mooney viscosity (ML at 100° C.) of from about 35 to about 120, in other embodiments from about 55 to about 95, in other embodiments from about 60 to about 90, and in other embodiments from about 65 to about 85, within 24 hours of desolventization and drying. 1+4 For purposes of this specification, dry, unaged Mooney viscosity (ML at 100°C) is used. 1+4 ) is sometimes referred to as Beer's Mooney viscosity. Polymer properties after aging

[0057] As mentioned above, the polymers of the present invention have advantageous aged Mooney viscosities (ML at 100°C). 1+4 Specifically, in one or more embodiments, the polymers have a Mooney viscosity (ML at 100° C.) of less than 120, in other embodiments less than 105, and in other embodiments less than 95, when aged for two years after desolventization and drying. 1+4 In one or more embodiments, the polymer, when aged for 2 years after desolventization and drying, has a Mooney viscosity (ML at 100° C.) of from about 70 to about 120, in other embodiments from about 80 to about 105, and in other embodiments from about 85 to about 95. 1+4) For purposes herein, specifically with respect to the Mooney viscosity after 2 years aging, accelerated aging may be performed at 100°C for 2 days instead of 2 years of room temperature aging. In other words, for purposes herein, the two aging methods are treated equally with respect to the resulting viscosity.

[0058] In one or more embodiments, the method of the present invention includes selecting from the ranges disclosed herein (i) the peak molecular weight of the base polymer, (ii) the desired loading of functionalizing agent, and (iii) an appropriate loading of stabilizer to meet a target aged Mooney viscosity (e.g., less than 120) within the range of the following formula: Mooney after aging = -34.2 + [0.828 Beer Mooney Viscosity] + [0.348 Base Mp] - [0.425% Coupling %] + [98.9 Functionalizing Agent Equivalents] - [6.16 Stabilizing Agent Equivalents] (In the formula, Mooney after aging is the ML at 100°C after heat aging at 100°C for 48 hours.) 1+4 and the Mooney viscosity of the bale is ML at 100°C within 24 hours of desolventization and drying. 1+4 where Base Mp represents the peak molecular weight (kg / mol) of the base polymer as determined by GPC using polystyrene standards and the polystyrene Mark-Hwink constant, % Coupling is the percentage of coupled polymer upon desolvation as determined by GPC, Functionalizing Agent Equivalent is the number of moles of functionalizing agent per mole of lithium used to initiate polymerization of the polymer, and Stabilizing Agent Equivalent is the number of moles of stabilizer per mole of lithium used to stabilize the polymer).

[0059] In one or more embodiments, the above formula is satisfied for the Mooney after aging when the Mooney viscosity is 120 or less (or other ranges disclosed herein), the Beer Mooney viscosity is about 35 to about 120, the Mp is about 160 to about 180 kg / mol, the % coupling is about 20% to about 80%, the functionalizing agent equivalent weight is about 0.2 to about 0.8 moles of functionalizing agent per mole of lithium, and the stabilizer equivalent weight is about 1 to about 12 moles of stabilizer per mole of lithium. As will be appreciated by those of skill in the art, the above formula may also be satisfied for other ranges disclosed herein (e.g., other ranges of functionalizing agent equivalent weight). Industrial Applicability

[0060] The polymers of the present invention are particularly useful in preparing rubber compositions that can be used to manufacture tire components. Rubber compounding techniques and the additives used therein are generally described in The Compounding and Vulcanization of Rubber, in Rubber Technology (2002). nd This is disclosed in "Ed. 1973."

[0061] Rubber compositions can be prepared by using the polymers of the present invention alone or with other elastomers (i.e., polymers that can be vulcanized to form compositions with rubbery or elastomeric properties). Other elastomers that may be used include natural and synthetic rubbers. Synthetic rubbers are typically obtained from the polymerization of conjugated diene monomers, copolymerization of conjugated diene monomers with other monomers (e.g., vinyl-substituted aromatic monomers), or copolymerization of ethylene with one or more α-olefins and, optionally, one or more diene monomers.

[0062] Exemplary elastomers include natural rubber, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have a myriad of macromolecular structures, such as linear, branched, and star structures.

[0063] The rubber composition may contain fillers, such as inorganic and organic fillers. Examples of organic fillers include carbon black and starch. Examples of inorganic fillers include silica, aluminum hydroxide, magnesium hydroxide, mica, talc (hydrated magnesium silicate), and clay (hydrated aluminum silicate). Carbon black and silica are the most common fillers used in tire manufacturing. In some embodiments, a mixture of different fillers may be advantageously used.

[0064] In one or more embodiments, carbon blacks include furnace blacks, channel blacks, and lamp blacks. More specific examples of carbon blacks include super abrasion furnace blacks, medium super abrasion furnace blacks, high abrasion furnace blacks, high speed extrusion furnace blacks, fine furnace blacks, semi-reinforced furnace blacks, medium processed channel blacks, hard processed channel blacks, conductive channel blacks, and acetylene blacks.

[0065] In certain embodiments, the carbon black has a surface area (EMSA) of at least 20 m 2 / g, in other embodiments at least 35m 2The surface area may be expressed in terms of 1 / g, and the surface area value may be determined using the cetyltrimethylammonium bromide (CTAB) technique according to ASTM standard D-1765. The carbon black may be in pelletized or non-pelletized flocculent form. The preferred form of the carbon black may depend on the type of mixing equipment used to mix the rubber compound.

[0066] The amount of carbon black used in the rubber composition may be up to about 50 parts by weight per 100 parts by weight of rubber (phr), with about 5 to about 40 phr being typical.

[0067] Some commercially available silicas that can be used include Hi-Sil™ 215, Hi-Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh, Pa.) Other suppliers of commercially available silica include Grace Davison (Baltimore, Md.), Degussa Corp. (Parsippany, NJ), Rhodia Silica Systems (Cranbury, NJ), and JM Huber Corp. (Edison, NJ).

[0068] In one or more embodiments, silica can be characterized by its surface area, which is a measure of its reinforcing properties. The Brunauer, Emmett, and Teller ("BET") method (described in J. Am. Chem. Soc., 1939, vol. 60, 2 pp. 309-319) is an accepted method for determining surface area. The BET surface area of ​​silica is generally 450 m 2 / g. A useful range of surface area is from about 32 to about 400 m 2 / g, about 100~250m 2 / g, about 150~220m 2 / g is an example.

[0069] The pH of the silica is generally from about 5 to about 7, or slightly above 7, or in other embodiments, from about 5.5 to about 6.8.

[0070] In one or more embodiments, when silica is used as a filler (alone or in combination with other fillers), a coupling agent and / or shielding agent may be added to the rubber composition during mixing to enhance interaction of the silica with the elastomer. Useful coupling agents and shielding agents are disclosed in U.S. Patent Nos. 3,842,111, 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,674,932, and 5,680,919. Nos. 4,171, 5,684,172, 5,696,197, 6,608,145, 6,667,362, 6,579,949, 6,590,017, 6,525,118, 6,342,552, and 6,683,135, which are incorporated herein by reference.

[0071] The amount of silica used in the rubber composition can be from about 1 to about 100 phr, or in other embodiments, from about 5 to about 80 phr. The useful upper range is limited by the high viscosity imparted by the silica. When silica is used in conjunction with carbon black, the amount of silica can be as low as about 1 phr. Because the amount of silica is low, less coupling and shielding agents can be used. Generally, the amount of coupling and shielding agents ranges from about 4% by weight to about 20% by weight, based on the weight of silica used.

[0072] A number of rubber curing agents (also called vulcanizing agents) may be used, including sulfur- or peroxide-based cure systems. Curing agents are described in Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 20, pp. 365-468, (3rd Ed. 1982), particularly "Vulcanization Agents and Auxiliary Materials," pp. 390-402, and A.Y. Coran, "Vulcanization," Encyclopedia of Polymer Science and Engineering, (2nd Ed. 1989), which are incorporated herein by reference. Vulcanizing agents may be used alone or in combination.

[0073] Other components typically used in rubber compounding may also be added to the rubber composition. These include accelerators, accelerator activators, oils, plasticizers, waxes, antiscorch agents, processing aids, zinc oxide, tackifying resins, reinforcing resins, fatty acids such as stearic acid, deflocculants, antidegradants such as antioxidants and antiozonants. In certain embodiments, the oils used include those traditionally used as extending oils, as previously described.

[0074] All components of the rubber composition can be mixed using standard mixing equipment, such as a Banbury or Brabender mixer, an extruder, a kneader, and a two-roll mill. In one or more embodiments, the components are mixed in two or more stages. In the first stage (often referred to as the masterbatch mixing stage), a so-called masterbatch (typically containing the rubber component and filler) is prepared. To prevent premature vulcanization (also known as scorch), vulcanizing agents may be omitted from the masterbatch. The masterbatch may be mixed at an initial temperature of about 25°C to about 125°C, with an extrusion temperature of about 135°C to about 180°C. Once the masterbatch is prepared, vulcanizing agents may be introduced and mixed into the masterbatch in a final mixing stage, which is typically performed at a relatively low temperature to reduce the possibility of premature vulcanization. Optionally, an additional mixing stage, often referred to as a re-mill, can be used between the masterbatch mixing stage and the final mixing stage. When silica is included as a filler in the rubber composition, one or more re-mill stages are often used. The addition of various ingredients, including the polymers of the present invention, can occur during these remills.

[0075] Mixing procedures and conditions particularly applicable to silica-filled tire compounds are described in U.S. Patent Nos. 5,227,425, 5,719,207, and 5,717,022, and European Patent No. 890,606, all of which are incorporated herein by reference. In one embodiment, an initial masterbatch is prepared by including the polymer and silica in the substantial absence of coupling and shielding agents.

[0076] Rubber compositions prepared from the polymers of this invention are particularly useful in forming tire components such as treads, subtreads, sidewalls, body ply skims, bead fillers, etc. In one or more embodiments, these tread or sidewall compounds may contain from about 10% to about 100% by weight, in other embodiments from about 35% to about 90% by weight, and in other embodiments from about 50% to about 80% by weight of the polymers of this invention (based on the total weight of rubber in the compound).

[0077] When rubber compositions are used in tire manufacture, they can be processed into tire components using conventional tire manufacturing techniques, such as standard rubber molding, molding, and curing techniques. Typically, vulcanization is accomplished by heating the vulcanizable composition in a mold, e.g., to about 140 to about 180°C. The cured or crosslinked rubber composition can be referred to as a vulcanizate, which generally contains a thermoset three-dimensional polymer network. Other ingredients (e.g., fillers and processing aids) may be uniformly dispersed throughout the crosslinked network. Pneumatic tires can be made as discussed in U.S. Pat. Nos. 5,866,171, 5,876,527, 5,931,211, and 5,971,046, which are incorporated herein by reference.

[0078] In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. However, these examples should not be construed as limiting the scope of the invention. The claims shall define the invention. [Example]

[0079] Several polymer samples were prepared in a 378.5 L reactor equipped with a heating / cooling jacket and agitator blade. Butyllithium was used to anionically initiate random polymerization of butadiene and styrene with hexane in a polymerization mixture containing approximately 18 wt% monomer. The target base molecular weight was 215 kg / mol (polystyrene standard) and was achieved based on the butyllithium input. The styrene to butadiene ratio was adjusted to obtain a polymer with 10 wt% styrene and the remainder butadiene. The vinyl content was targeted at 41.5 wt% of butadiene mer units, which was achieved by using 2,2-di(tetrahydrofuryl)propane as the vinyl modifier. For example, in one or more samples, 35.397 kg of hexane, 7.579 kg of 33.0 wt% styrene in hexane, and 135.669 kg of 21.2 wt% butadiene in hexane were initially charged to a reactor, then 0.511 kg of 3 wt% butyllithium was added, followed by 0.012 kg of 2,2-di(tetrahydrofuryl)propane. It should be understood that this is merely exemplary, and that the various components (e.g., butyllithium) in the samples were manipulated to achieve the properties listed in Table I.

[0080] The monomers and solvent were charged into the reactor at room temperature, stirred, and heated to a stabilization temperature of 33° C. Then, external heating was discontinued and the butyllithium initiator was charged to form a polymerization mixture. The polymerization mixture generally produced an exothermic peak about 23 minutes after the butyllithium was charged, and the polymerization mixture was incubated at about 85° C. using a cooling jacket.

[0081] Within about 5 minutes of peak polymerization temperature, 3-(1,3-dimethylbutylidene)aminopropyltriethoxysilane (DMAPT) was charged to the reactor in the amount provided in Table I. The polymerization mixture was continuously stirred for about 30 minutes, and then a blend of ethylhexanoic acid (EHA) and octyltriethoxysilane (OTES) was charged to the reactor in the amount shown in Table I. 0.252 kg of butylated hydroxytoluene (BHT) was then charged. At this point in the process, the peak molecular weight was analyzed by GPC using polystyrene standards and polystyrene Mark-Hwink constants (this analysis was also used to determine % coupling), as well as Mooney viscosity (ML at 100°C). 1+4 ) The polymer analyzed at this point in the process is sometimes referred to as the "blending tank" (e.g., blending tank Mooney). For purposes of this specification and invention, blending tank Mooney and desolventization Mooney are considered equivalent.

[0082] The polymerization mixture was then transferred to an aqueous desolventization process. Specifically, a water-containing tank was heated to a temperature of about 82° C. The polymerization mixture was slowly added to the tank, and the hexane was evaporated. Volatiles were collected in a condenser. The polymer coagulated in the presence of water to form a coagulated polymer dispersion. The polymer was then dehydrated by passing the polymer-water mixture through a grinder (i.e., a single-screw extruder equipped with a perforated die). The dehydrated polymer was then dried in a 71°C oven for 1 hour and then heated in a 60°C oven until dry (e.g., water content less than about 0.5 wt%). After drying, the polymer was baled and the Mooney viscosity (ML at 100°C) was measured. 1+4 The Mooney viscosity (ML at 100°C) of the aged samples was then measured to obtain the raw Mooney viscosity of the bale. Samples of the bale were aged by placing them in an oven at 100°C for 48 hours. 1+4 ) was measured. [Table 1-1] [Table 1-2]

[0083] The data in Table I was analyzed by linear least squares regression analysis using Minitab™, which provided the above equations for predicting blending tank and post-aging Mooney with 95% confidence intervals.

[0084] Various modifications and alterations that do not depart from the scope and spirit of the present invention will be apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein. The present disclosure includes the following embodiments. <1> 1. A process for preparing a stabilized diene copolymer having terminal modifications, comprising: (i) combining an organolithium compound, butadiene monomer, and styrene monomer, optionally together with a vinyl modifier, in a solvent to form a polymerization mixture; (ii) polymerizing the monomers, thereby forming a living polymer; (iii) after the step of polymerizing the monomers, introducing an imine-containing hydrocarbyloxysilane compound into the polymerization mixture, wherein the imine-containing hydrocarbyloxysilane is added in an amount of about 0.2 to 0.8 moles per mole of organolithium compound, thereby forming a polymerization mixture comprising a modified polymer; (iv) after the step of introducing the imine-containing hydrocarbyloxysilane, introducing a hydrocarbyl hydrocarbyloxysilane into the polymerization mixture containing the modified polymer, thereby forming a stabilized polymerization mixture, wherein the hydrocarbyl hydrocarbyloxysilane is added in an amount of from about 1 to about 12 moles per mole of organolithium compound; (v) desolventizing the polymer mixture to provide the stabilized diene copolymer having said terminal modifications; The process includes: <2> the step of desolventizing comprises steam or water coagulation of the stabilized polymerization mixture to provide a wet polymer mass comprising the modified polymer, and drying the wet polymer mass to provide a dry modified polymer. <1> The process described in <3> wherein the step of polymerizing the monomers achieves a peak polymerization temperature, and the step of introducing an amine-containing hydrocarbyloxysilane compound into the polymerization mixture occurs after the peak polymerization temperature; <1> or <2> The process described in <4> the step of combining an organolithium compound, butadiene monomer, and styrene monomer comprises using from about 0.05 to about 50 millimoles of butyllithium per 100 grams of total monomers; <1> ~ <3> 2. The process according to claim 1, wherein <5> The living polymer is characterized in that it has a base Mp of about 160 to about 280 kg per mole as determined by GPC using polystyrene standards and polystyrene Mark-Hwink constants. <1> ~ <4> 2. The process according to claim 1, wherein <6> The living polymer is characterized in that it contains about 5 to about 45% by weight of styrene mer units and about 10 to about 80% vinyl content. <1> ~ <5> 2. The process according to claim 1, wherein <7> The polymerization mixture containing the modified polymer contains about 10 to about 80 mol % of the modified polymer. <1> ~ <6> 2. The process according to claim 1, wherein <8> the amine-containing hydrocarbyloxysilane is selected from the group consisting of N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine, or N-(4-N,N-dimethylaminobenzylidene)-3-(triethoxysilyl)-1-propanamine; <1> ~ <7> In certain embodiments, the imine-containing hydrocarbyloxysilane is N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine and N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine. <9> the step of introducing an amine-containing hydrocarbyloxysilane comprises adding the amine-containing hydrocarbyloxysilane to the polymerization mixture in an amount of from about 0.3 to about 0.7 moles per mole of organolithium compound; <1> ~ <8> 2. The process according to claim 1, wherein <10> the hydrocarbyl hydrocarbyloxysilane is selected from the group consisting of trihydrocarbyl hydrocarbyloxysilane, dihydrocarbyl dihydrocarbyloxysilane, hydrocarbyl trihydrocarbyloxysilane, and tetrahydrocarbyloxysilane; <1> ~ <9> 2. The process according to claim 1, wherein <11> the step of introducing the hydrocarbylhydrocarbyloxysilane comprises introducing about 3 to about 10 moles per mole of the organolithium compound; <1> ~ <10> 2. The process according to claim 1, wherein <12> The method further comprises the step of introducing a condensation promoter into the polymerization mixture or the stabilized polymerization mixture containing the modified polymer. <1> ~ <11> 2. The process according to claim 1, wherein <13> The amount of the condensation promoter introduced is about 1.0 to about 4.0 moles per mole of lithium. <12> The process described in <14> The modified polymer in the stabilized polymerization mixture has a Mooney viscosity (ML at 100° C.) of greater than 50. 1+4 ) <1> ~ <13> 2. The process according to claim 1, wherein <15> the stabilized polymerization mixture is operated to provide a modified polymer that satisfies the following formula: <1> ~ <14> 12. The process according to claim 11, wherein: Mooney viscosity after desolvation = 44.7 + [0.5218 base Mp] - [5.1 functionalizing agent equivalents] - [4.765 stabilizer equivalents] + [8.86 condensation accelerator equivalents] (wherein the Mooney viscosity after desolvation is 50 or more, Mp is about 160 to about 280 kg / mol, the functionalizing agent equivalent is about 0.2 to about 0.8 mol per mol of the organolithium compound, the stabilizer equivalent is about 1 to about 12 mol per mol of the organolithium compound, and the condensation promoter equivalent is about 1 to about 4 mol per mol of the organolithium compound). <16> The stabilized diene copolymer has a Mooney viscosity (ML at 100°C) of less than 120 after heat aging at 100°C for 48 hours. 1+4 ) and the process is carried out so as to satisfy the following formula: <1> ~ <15> 12. The process according to claim 11, wherein: Mooney after aging = -34.2 + [0.828 Beer Mooney Viscosity] + [0.348 Base Mp] - [0.425% Coupling %] + [98.9 Functionalizing Agent Equivalents] - [6.16 Stabilizing Agent Equivalents] wherein the post-aging Mooney is 120 or less, the Beer Mooney viscosity is about 35 to about 120, the Mp is about 160 to about 280 kg / mol, the % coupling is about 20 to about 80%, the functionalizing agent equivalent is about 0.2 to about 0.8 moles per mole of organolithium compound, and the stabilizer equivalent is about 1 to about 12 moles per mole of lithium.

Claims

1. (i) In a solvent, an organolithium compound, a butadiene monomer, and a styrene monomer are combined with an optionally selected vinyl modifier to form a polymerization mixture. (ii) Polymerizing the monomers to form a living polymer, (iii) After the step of polymerizing the monomer, an imine-containing hydrocarbyloxysilane compound is introduced into the polymerization mixture as a modifier, wherein the imine-containing hydrocarbyloxysilane compound is added in an amount of 0.2 to 0.8 moles per mole of organolithium compound, thereby forming a polymerization mixture containing a modified polymer, (iv) After the step of introducing an imine-containing hydrocarbyloxysilane compound, hydrocarbylhydrocarbyloxysilane is introduced as a stabilizer into the polymerization mixture containing the modified polymer, thereby forming a stabilized polymerization mixture, wherein the hydrocarbylhydrocarbyloxysilane is added in an amount of 1 to 12 moles per mole of organolithium compound to form a stabilized polymerization mixture. (v) To provide a stabilized diene copolymer having terminal modification by desolvating the polymer mixture, A process for preparing a stabilized diene copolymer having terminal modification, comprising: In order to achieve the target Mooney viscosity during desolvation and the target Mooney viscosity after aging, the peak molecular weight of the base polymer of the stabilized polymerization mixture, the amount of the modifier, the amount of the stabilizer, the coupling efficiency measured by the coupling % of the base polymer of the stabilized polymerization mixture, and the amount of the condensation accelerator are all taken into consideration and adjusted. The stabilized diene copolymer is characterized by a post-aging Mooney viscosity of less than 120 (ML 1+4 at 100°C) after heating and aging at 100°C for 48 hours. The process is carried out to satisfy the following equation: Mooney viscosity after aging = -34.2 + [Mooney viscosity of 0.828 bales] + [0.348 base Mp] (unit of base Mp: kg per mole) - [0.425 coupling %] + [98.9 modifier equivalent] - [6.16 stabilizer equivalent] (In the formula, the Mooney viscosity after aging is less than 120, the Mooney viscosity of the bale is 35 to 120, the base Mp is 160 to 280 kg per mole, the coupling % is 20 to 80%, the modifier equivalent is 0.2 to 0.8 moles per mole of organolithium compound, and the stabilizer equivalent is 1 to 12 moles per mole of lithium.)

2. The process according to claim 1, wherein the solvent removal step comprises providing a wet polymer mass containing the modified polymer by vapor or water coagulation of the stabilized polymerization mixture, and drying the wet polymer mass to provide a dry modified polymer.

3. The process according to claim 1, wherein the step of polymerizing a monomer is performed to achieve a peak polymerization temperature, and the step of introducing an imine-containing hydrocarbyloxysilane compound into the polymerization mixture is performed after the peak polymerization temperature.

4. The process according to claim 1, operated to provide a modified polymer in the stabilized polymerization mixture that satisfies the following formula: Mooney viscosity after solvent removal = 44.7 + [0.5218 base Mp] (unit of base Mp: kg per mole) - [5.1 equivalent of modifier] - [4.765 equivalent of stabilizer] + [8.86 equivalent of condensation accelerator] (In the formula, the Mooney viscosity during desolvation is 50 to 105, where Mooney viscosity during desolvation is ML 1 + 4 at 100°C during the desolvation process, base Mp is 160 to 280 kg per mole, modifier equivalent is 0.2 to 0.8 moles per mole of organolithium compound, stabilizer equivalent is 1 to 12 moles per mole of organolithium compound, and condensation accelerator equivalent is 1 to 4 moles per mole of organolithium compound.)