Functionalized butadiene polymers in tire compounds and method of making same

Abstract

A polymer and rubber composition for a truck and bus radial include: butadiene rubber polymers having polymer chain ends; the butadiene rubber polymers including (a) a 1,4-cis content of 90% or greater; and (b) a functional group including a heteroarylcarbonitrile molecule. 30% or more of the polymer chain ends of the butadiene rubber polymers are functionalized with the functional group. A functionalized butadiene rubber is included in a rubber composition in an amount of about 10 to about 60 phr and a reinforcing filler component includes carbon black in a range of about 25 to about 70 phr wherein the carbon black is a majority of the reinforcing filler component.

Description

P22296WO1A; BSP183WO Functionalized Butadiene Polymers in Tire Compounds and Method of Making Same CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US provisional application No. 63 / 615,966, filed December 29, 2023 and US provisional application No.63 / 678,223, filed August 1, 2024. These prior applications are incorporated herein by reference. FIELD

[0002] This application is directed to tire tread rubber compositions and related methods. More specifically, it is directed to functionalized butadiene polymers for use in tire tread compositions and passenger or truck or bus type tires in particular. BACKGROUND

[0003] Tires comprise many components including a road-contacting tread. The particular ingredients used to prepare the rubber composition that comprises the tire tread may vary. Formulation of tire tread rubber compositions is a complex science since changes to the formulation that result in an improvement in one property (e.g., wear resistance) may result in changes to another property (e.g., traction). Improvements in tire wear resistance are always desirable to provide a product that lasts longer.

[0004] Technologies that reduce rubber compound glass transition temperature (Tg) or utilize lower Tg polymers, use polymers with increased molecular weights, or improve filler dispersion are known to improve wear resistance, however tradeoffs in other properties are common. Functionalization of polymer chain ends are known to improve certain properties of rubber compositions, but the interactions of the functional polymer chains are unpredictable as to their effectiveness and typically have detriments in other properties.

[0005] The number one cost for maintaining commercial trucking fleets behind fuel is are costs related to tires. Accordingly, even small improvements in wear resistance that lengthen the life of a commercial truck tire can provide substantialP22296WO1A; BSP183WO benefits to this industry. In particular, when traction and other properties are not significantly affected to achieve this improvement. SUMMARY

[0006] The technology disclosed herein addresses the need for improved wear tire treads. The following is a brief summary of subject matter that is described in greater detail herein. This summary is not intended to be limiting as to the scope of the claims.

[0007] In some aspects, the techniques described herein relate to a polymer composition including: butadiene rubber polymers having polymer chain ends; the butadiene rubber polymers including (a) a 1,4-cis content of 90% or greater; and (b) a functional group including a heteroarylcarbonitrile molecule; wherein 30% or more of the polymer chain ends of the butadiene rubber polymers are functionalized with the functional group; wherein the butadiene rubber polymer has a nitrogen content of about 50 to about 500 ppm, preferably about 75 to about 400 ppm, more preferably about 100 to about 300 ppm, more preferably about 175 to 275 ppm.

[0008] In some aspects, the techniques described herein relate to a rubber composition for a tire tread including: a rubber component including a functionalized butadiene rubber in an amount of about 10 to about 60 phr, the functionalized butadiene rubber including a 1,4-cis content of 90% or greater, and a functional group including a heteroarylcarbonitrile molecule; and a natural rubber, polyisoprene rubber, and / or styrene-butadiene rubber; and a reinforcing filler component including carbon black in a range of about 25 to about 70 phr wherein the carbon black is a majority of the reinforcing filler component.

[0009] In some aspects, the techniques described herein relate to a tire tread for application on tires having a load index of about 117 or more, the tread including: a rubber component including a functionalized butadiene rubber in an amount of about 10 to about 60 phr, the functionalized butadiene rubber including a 1,4-cis content of about 90% or greater, and a functional group including a heteroarylcarbonitrile molecule; a natural rubber, polyisoprene rubber, and / or styrene-butadiene rubber; andP22296WO1A; BSP183WO a reinforcing filler component including carbon black in a range of about 25 to about 70 phr wherein the carbon black is a majority of the reinforcing filler component.

[0010] In some aspects, the techniques described herein relate to a method of making a functional polymer, the method including: (a) preparing a catalyst composition by combining a lanthanide-containing compound, an alkylating agent, and a halogen source; (b) aging the catalyst composition to form an aged catalyst composition, where said step of aging includes aging for more than 24 hours, preferably more than 5 days, more preferably more than 30 days; (c) combining the aged catalyst composition, additional alkylating agent, and conjugated diene monomer to be polymerized to form a polymerization system that produces a polydiene having a reactive chain end, wherein an amount of total aluminum employed relative to a total amount of the conjugated diene monomer is less than 5 mmol per 100 grams of the conjugated diene monomer, where said step of combining includes combining from about 0.001 to about 2 mmol of the lanthanide-containing compound per 100 grams of the conjugated diene monomer to be polymerized; and (d) introducing a functionalizing agent to the polymerization system to thereby prepare the functional polymer; wherein the functional polymer has a nitrogen content of about 50 to about 500 ppm, more preferably about 75 to about 400 ppm, preferably about 100 to about 300 ppm, more preferably about 175 to 275 ppm.

[0011] The above summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and / or methods discussed herein. This summary is not an extensive overview of the systems and / or methods discussed herein. It is not intended to identify key / critical elements or to delineate the scope of such systems and / or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. DETAILED DESCRIPTION

[0012] The synthesis of a high-cis butadiene rubber (HCBR or high-cis BR) with 30% or more of the polymer chain ends functionalized by a heteroarylcarbonitrile group including but not limited to pyrazinecarbonitrile is described herein. Furthermore, theP22296WO1A; BSP183WO use of this functional polymer in a tire tread formulation is disclosed. Test data indicates that this composition improves wear properties in tire tread compounds.

[0013] In an embodiment, the method of making is exclusive of a catalyst that includes methylaluminoxane (MAO) , and the functional polymer is exclusive of remnants of a neodymium catalyst that contains MAO or any catalyst that contains MAO. Instead, in an embodiment, the catalyst used in the making of the functional polymer disclosed herein is a pre-formed lanthanide catalyst, such as for example, a pre- formed neodymium catalyst comprising an alkyl group, aluminum, and a halogen. For example, the catalyst and method of use of the catalyst disclosed in U.S.2023 / 0183399 may be used herein.

[0014] In an embodiment, the catalyst system employed includes (a) a lanthanide-containing compound, (b) an alkylating agent, and (c) a halogen source. In other embodiments, a compound containing a non-coordinating anion or a non- coordinating anion precursor can be employed in lieu of a halogen source. In these or other embodiments, other organometallic compounds, Lewis bases, and / or catalyst modifiers can be employed in addition to the ingredients or components set forth above. For example, in one embodiment, a nickel-containing compound can be employed as a molecular weight regulator as disclosed in U.S. Patent No.6,699,813, which is incorporated herein by reference.

[0015] As mentioned above, the lanthanide-based catalyst systems employed herein can include a lanthanide-containing compound. Such compounds may include at least one atom of lanthanum, neodymium, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and didymium. In one embodiment, these compounds can include neodymium, lanthanum, samarium, or didymium.

[0016] The lanthanide atom in the lanthanide-containing compounds can be in various oxidation states including, but not limited to, the 0, + 2, + 3, and +4 oxidation states. In one embodiment, a trivalent lanthanide-containing compound, where the lanthanide atom is in the +3 oxidation state, can be employed. Suitable lanthanide-P22296WO1A; BSP183WO containing compounds include, but are not limited to, lanthanide carboxylates, lanthanide organophosphates, lanthanide organophosphonates, lanthanide organophosphinates, lanthanide carbamates, lanthanide dithiocarbamates, lanthanide xanthates, lanthanide β-diketonates, lanthanide alkoxides or aryloxides, lanthanide halides, lanthanide pseudo-halides, lanthanide oxyhalides, and organolanthanide compounds.

[0017] In an embodiment, the lanthanide-containing compounds can be soluble in hydrocarbon solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, or cycloaliphatic hydrocarbons. Hydrocarbon-insoluble lanthanide-containing compounds, however, may also be useful in the present invention, as they can be suspended in the polymerization medium to form the catalytically active species.

[0018] For ease of illustration, further discussion of useful lanthanide-containing compounds will focus on neodymium compounds, although those skilled in the art will be able to select similar compounds that are based upon other lanthanide metals.

[0019] Suitable neodymium carboxylates include, but are not limited to, neodymium formate, neodymium acetate, neodymium acrylate, neodymium methacrylate, neodymium valerate, neodymium gluconate, neodymium citrate, neodymium fumarate, neodymium lactate, neodymium maleate, neodymium oxalate, neodymium 2- ethylhexanoate, neodymium neodecanoate (a.k.a., neodymium versatate), neodymium naphthenate, neodymium stearate, neodymium oleate, neodymium benzoate, and neodymium picolinate.

[0020] Suitable neodymium organophosphates include, but are not limited to, neodymium dibutyl phosphate, neodymium dipentyl phosphate, neodymium dihexyl phosphate, neodymium diheptyl phosphate, neodymium dioctyl phosphate, neodymium bis(l-methylheptyl) phosphate, neodymium bis(2-ethylhexyl) phosphate, neodymium didecyl phosphate, neodymium didodecyl phosphate, neodymium dioctadecyl phosphate, neodymium dioleyl phosphate, neodymium diphenyl phosphate, neodymium bis(p-nonylphenyl) phosphate, neodymium butyl (2-ethylhexyl) phosphate,P22296WO1A; BSP183WO neodymium (1-methylheptyl) (2-ethylhexyl) phosphate, and neodymium (2-ethylhexyl) (p-nonylphenyl) phosphate.

[0021] Suitable neodymium organophosphonates include, but are not limited to, neodymium butyl phosphonate, neodymium pentyl phosphonate, neodymium hexyl phosphonate, neodymium heptyl phosphonate, neodymium octyl phosphonate, neodymium (1 -methylheptyl) phosphonate, neodymium (2-ethylhexyl) phosphonate, neodymium decyl phosphonate, neodymium dodecyl phosphonate, neodymium octadecyl phosphonate, neodymium oleyl phosphonate, neodymium phenyl phosphonate, neodymium (p-nonylphenyl) phosphonate, neodymium butyl butylphosphonate, neodymium pentyl pentylphosphonate, neodymium hexyl hexylphosphonate, neodymium heptyl heptylphosphonate, neodymium octyl octylphosphonate, neodymium (1 -methylheptyl) (1 -methylheptyl) phosphonate, neodymium (2-ethylhexyl) (2-ethylhexyl)phosphonate, neodymium decyl decylphosphonate, neodymium dodecyl dodecylphosphonate, neodymium octadecyl octadecylphosphonate, neodymium oleyl oleylphosphonate, neodymium phenyl phenylphosphonate, neodymium (p-nonylphenyl) (p-nonylphenyl) phosphonate, neodymium butyl (2-ethylhexyl)phosphonate, neodymium (2-ethylhexyl) butylphosphonate, neodymium (1 -methylheptyl) (2-ethylhexyl)phosphonate, neodymium (2-ethylhexyl) (l-methylheptyl)phosphonate, neodymium (2-ethylhexyl) (p- nonylphenyl) phosphonate, and neodymium (p-nonylphenyl) (2- ethylhexyl)phosphonate.

[0022] Suitable neodymium organophosphinates include, but are not limited to, neodymium butylphosphinate, neodymium pentylphosphinate, neodymium hexylphosphinate, neodymium heptylphosphinate, neodymium octylphosphinate, neodymium (1 -methylheptyl) phosphinate, neodymium (2-ethylhexyl)phosphinate, neodymium decylphosphinate, neodymium dodecylphosphinate, neodymium octadecylphosphinate, neodymium oleylphosphinate, neodymium phenylphosphinate, neodymium (p-nonylphenyl) phosphinate, neodymium dibutylphosphinate, neodymium dipentylphosphinate, neodymium dihexylphosphinate, neodymiumP22296WO1A; BSP183WO diheptylphosphinate, neodymium dioctylphosphinate, neodymium bis (1 -methylheptyl) phosphinate, neodymium bis(2-ethylhexyl)phosphinate, neodymium didecylphosphinate, neodymium didodecylphosphinate, neodymium dioctadecylphosphinate, neodymium dioleylphosphinate, neodymium diphenylphosphinate, neodymium bis(p-nonylphenyl) phosphinate, neodymium butyl (2-ethylhexyl) phosphinate, neodymium (1- methylheptyl)(2-ethylhexyl)phosphinate, and neodymium (2-ethylhexyl) (p- nonylphenyl)phosphinate. Suitable neodymium carbamates include, but are not limited to, neodymium dimethylcarbamate, neodymium diethylcarbamate, neodymium diisopropylcarbamate, neodymium dibutylcarbamate, and neodymium dibenzylcarbamate.

[0023] Suitable neodymium dithiocarbamates include, but are not limited to, neodymium dimethyldithiocarbamate, neodymium diethyldithiocarbamate, neodymium diisopropyldithiocarbamate, neodymium dibutyldithiocarbamate, and neodymium dibenzyldithiocarbamate.

[0024] Suitable neodymium xanthates include, but are not limited to, neodymium methylxanthate, neodymium ethylxanthate, neodymium isopropylxanthate, neodymium butylxanthate, and neodymium benzylxanthate.

[0025] Suitable neodymium β-diketonates include, but are not limited to, neodymium acetylacetonate, neodymium trifluoroacetylacetonate, neodymium hexafluoroacetylacetonate, neodymium benzoylacetonate, and neodymium 2,2,6,6- tetramethyl-3,5-heptanedionate.

[0026] Suitable neodymium alkoxides or aryloxides include, but are not limited to, neodymium methoxide, neodymium ethoxide, neodymium isopropoxide, neodymium 2- ethylhexoxide, neodymium phenoxide, neodymium nonylphenoxide, and neodymium naphthoxide.

[0027] Suitable neodymium halides include, but are not limited to, neodymium fluoride, neodymium chloride, neodymium bromide, and neodymium iodide. Suitable neodymium pseudo-halides include, but are not limited to, neodymium cyanide, neodymium cyanate, neodymium thiocyanate, neodymium azide, and neodymiumP22296WO1A; BSP183WO ferrocyanide. Suitable neodymium oxyhalides include, but are not limited to, neodymium oxyfluoride, neodymium oxychloride, and neodymium oxybromide. A Lewis base, such as tetrahydrofuran ("THF"), may be employed as an aid for solubilizing this class of neodymium compounds in inert organic solvents. Where lanthanide halides, lanthanide oxyhalides, or other lanthanide-containing compounds containing a halogen atom are employed, the lanthanide-containing compound may optionally also provide all or part of the halogen source in the lanthanide-based catalyst system.

[0028] As used herein, the term organolanthanide compound refers to any lanthanide-containing compound containing at least one lanthanide-carbon bond. These compounds are predominantly, though not exclusively, those containing cyclopentadienyl ("Cp"), substituted cyclopentadienyl, allyl, and substituted allyl ligands. Suitable organolanthanide compounds include, but are not limited to, Cp3Ln, Cp2LnR, Cp2LnCl, CpLnCl2, CpLn(cyclooctatetraene), (C5Me5)2LnR, LnR3, Ln(allyl)3, and Ln(allyl)2Cl, where Ln represents a lanthanide atom, and R represents a hydrocarbyl group. In an embodiment, hydrocarbyl groups useful in the present invention may contain heteroatoms such as, for example, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

[0029] In an embodiment, organoaluminum compounds that can be utilized in the lanthanide-based catalyst system include those represented by the general formula AlRnX3-n, where each R independently can be a monovalent organic group that is attached to the aluminum atom via a carbon atom, where each X independently can be a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and where n can be an integer in the range of from 1 to 3. In an embodiment, each R independently can be a hydrocarbyl group such as, for example, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl, substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups, with each group containing in the range of from 1 carbon atom, or the appropriate minimum number of carbon atoms to form the group, up to about 20 carbon atoms. These hydrocarbylP22296WO1A; BSP183WO groups may contain heteroatoms including, but not limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

[0030] Types of the organoaluminum compounds that are represented by the general formula AlRnX3-n include, but are not limited to, trihydrocarbylaluminum, dihydrocarbylaluminum hydride, hydrocarbylaluminum dihydride, dihydrocarbylaluminum carboxylate, hydrocarbylaluminum bis (carboxylate), dihydrocarbylaluminum alkoxide, hydrocarbylaluminum dialkoxide, dihydrocarbylaluminum halide, hydrocarbylaluminum dihalide, dihydrocarbylaluminum aryloxide, and hydrocarbylaluminum diaryloxide compounds. In one embodiment, the alkylating agent can comprise trihydrocarbylaluminum, dihydrocarbylaluminum hydride, and / or hydrocarbylaluminum dihydride compounds. In one embodiment, when the alkylating agent includes an organoaluminum hydride compound, the above-mentioned halogen source can be provided by a tin halide, as disclosed in U.S. Patent No. 7,008,899, which is incorporated herein by reference in its entirety.

[0031] Suitable trihydrocarbylaluminum compounds include, but are not limited to, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, tri-t-butylaluminum, tri-n-pentylaluminum, trineopentylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tris(2- ethylhexyl) aluminum, tricyclohexylaluminum, tris ( 1 -methylcyclopentyl) aluminum, triphenylaluminum, tri-p-tolylaluminum, tris(2,6-dimethylphenyl)aluminum, tribenzylaluminum, diethylphenylaluminum, diethyl-p-tolylaluminum, diethylbenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum, and ethyldibenzylaluminum.

[0032] Suitable dihydrocarbylaluminum hydride compounds include, but are not limited to, diethylaluminum hydride, di-n-propylaluminum hydride, diisopropylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, di-n-octylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride, phenylethylaluminum hydride, phenyl-n- propylaluminum hydride, phenylisopropylaluminum hydride, phenyl-n-butylaluminum hydride,P22296WO1A; BSP183WO phenylisobutylaluminum hydride, phenyl-n-octylaluminum hydride, p- tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride, p- tolylisopropylaluminum hydride, p-tolyl-n-butylaluminum hydride, p- tolylisobutylaluminum hydride, p-tolyl-n-octylaluminum hydride, benzylethylaluminum hydride, benzyl-n-propylaluminum hydride, benzylisopropylaluminum hydride, benzyl-n- butylaluminum hydride, benzylisobutylaluminum hydride, and benzyl-n-octylaluminum hydride.

[0033] Suitable hydrocarbylaluminum dihydrides include, but are not limited to, ethylaluminum dihydride, n-propylaluminum dihydride, isopropylaluminum dihydride, n-butylaluminum dihydride, isobutylaluminum dihydride, and n-octylaluminum dihydride.

[0034] Suitable dihydrocarbylaluminum halide compounds include, but are not limited to, diethylaluminum chloride, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, diphenylaluminum chloride, di-p-tolylaluminum chloride, dibenzylaluminum chloride, phenylethylaluminum chloride, phenyl-n- propylaluminum chloride, phenylisopropylaluminum chloride, phenyl-n-butylaluminum chloride, phenylisobutylaluminum chloride, phenyl-n-octylaluminum chloride, p- tolylethylaluminum chloride, p-tolyl-n-propylaluminum chloride, p- tolylisopropylaluminum chloride, p-tolyl-n-butylaluminum chloride, p- tolylisobutylaluminum chloride, p-tolyl-n-octylaluminum chloride, benzylethylaluminum chloride, benzyl-n-propylaluminum chloride, benzylisopropylaluminum chloride, benzyl- n-butylaluminum chloride, benzylisobutylaluminum chloride, and benzyl-n- octylaluminum chloride.

[0035] Suitable hydrocarbylaluminum dihalide compounds include, but are not limited to, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, and n- octylaluminum dichloride.P22296WO1A; BSP183WO

[0036] Other organoaluminum compounds useful as alkylating agents that may be represented by the general formula AlRnX3-n include, but are not limited to, dimethylaluminum hexanoate, diethylaluminum octoate, diisobutylaluminum 2- ethylhexanoate, dimethylaluminum neodecanoate, diethylaluminum stearate, diisobutylaluminum oleate, methylaluminum bis (hexanoate), ethylaluminum bis (octoate), isobutylaluminum bis(2-ethylhexanoate), methylaluminum bis (neodecanoate), ethylaluminum bis (stearate), isobutylaluminum bis(oleate), dimethylaluminum methoxide, diethylaluminum methoxide, diisobutylaluminum methoxide, dimethylaluminum ethoxide, diethylaluminum ethoxide, diisobutylaluminum ethoxide, dimethylaluminum phenoxide, diethylaluminum phenoxide, diisobutylaluminum phenoxide, methylaluminum dimethoxide, ethylaluminum dimethoxide, isobutylaluminum dimethoxide, methylaluminum diethoxide, ethylaluminum diethoxide, isobutylaluminum diethoxide, methylaluminum diphenoxide, ethylaluminum diphenoxide, and isobutylaluminum diphenoxide.

[0037] As mentioned above, the lanthanide-based catalyst systems employed in the present functional polymer can include a halogen source. As used herein, the term halogen source refers to any substance including at least one halogen atom. In an embodiment, at least a portion of the halogen source can be provided by either of the above-described lanthanide-containing compound and / or the above-described alkylating agent, when those compounds contain at least one halogen atom. In other words, the lanthanide-containing compound can serve as both the lanthanide- containing compound and at least a portion of the halogen source. Similarly, the alkylating agent can serve as both the alkylating agent and at least a portion of the halogen source.

[0038] In another embodiment, at least a portion of the halogen source can be present in the catalyst systems in the form of a separate and distinct halogen-containing compound. Various compounds, or mixtures thereof, that contain one or more halogen atoms can be employed as the halogen source. Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine. A combination of two orP22296WO1A; BSP183WO more halogen atoms can also be utilized. Halogen-containing compounds that are soluble in a hydrocarbon solvent are suitable for use in the present invention. Hydrocarbon-insoluble halogen-containing compounds, however, can be suspended in a polymerization system to form the catalytically active species, and are therefore also useful.

[0039] Useful types of halogen-containing compounds that can be employed include, but are not limited to, elemental halogens, mixed halogens, hydrogen halides, organic halides, inorganic halides, metallic halides, and organometallic halides.

[0040] Suitable elemental halogens include, but are not limited to, fluorine, chlorine, bromine, and iodine. Some specific examples of suitable mixed halogens include iodine monochloride, iodine monobromide, iodine trichloride, and iodine pentafluoride.

[0041] Suitable hydrogen halides include, but are not limited to, hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide.

[0042] Suitable organic halides include, but are not limited to, t-butyl chloride, t- butyl bromide, allyl chloride, allyl bromide, benzyl chloride, benzyl bromide, chloro-di- phenylmethane, bromo-di-phenylmethane, triphenylmethyl chloride, triphenylmethyl bromide, benzylidene chloride, benzylidene bromide, methyltrichlorosilane, phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, benzoyl chloride, benzoyl bromide, propionyl chloride, propionyl bromide, methyl chloroformate, and methyl bromoformate.

[0043] Suitable inorganic halides include, but are not limited to, phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride, phosphorus oxychloride, phosphorus oxybromide, boron trifluoride, boron trichloride, boron tribromide, silicon tetrafluoride, silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, arsenic trichloride, arsenic tribromide, arsenic triiodide, selenium tetrachloride, selenium tetrabromide, tellurium tetrachloride, tellurium tetrabromide, and tellurium tetraiodide.

[0044] Suitable metallic halides include, but are not limited to, tin tetrachloride, tin tetrabromide, aluminum trichloride, aluminum tribromide, antimony trichloride,P22296WO1A; BSP183WO antimony pentachloride, antimony tribromide, aluminum triiodide, aluminum trifluoride, gallium trichloride, gallium tribromide, gallium triiodide, gallium trifluoride, indium trichloride, indium tribromide, indium triiodide, indium trifluoride, titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, zinc dichloride, zinc dibromide, zinc diiodide, and zinc difluoride.

[0045] Suitable organometallic halides include, but are not limited to, dimethylaluminum chloride, diethylaluminum chloride, dimethylaluminum bromide, diethylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, methylaluminum dichloride, ethylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesium chloride, butylmagnesium bromide, phenylmagnesium chloride, phenylmagnesium bromide, benzylmagnesium chloride, trimethyltin chloride, trimethyltin bromide, triethyltin chloride, triethyltin bromide, di-t-butyltin dichloride, di- t-butyltin dibromide, dibutyltin dichloride, dibutyltin dibromide, tributyltin chloride, and tributyltin bromide.

[0046] The foregoing lanthanide-based catalyst composition may have high catalytic activity for polymerizing conjugated dienes into cis-1,4-polydienes over a wide range of catalyst concentrations and catalyst ingredient ratios, because the catalyst ingredients may interact to form an active species, the optimum concentration for any one catalyst ingredient may be dependent upon the concentrations of the other catalyst ingredients.

[0047] In an embodiment, the molar ratio of the alkylating agent to the lanthanide-containing compound (alkylating agent / Ln) can be varied from about 1 : 1 to about 1000:1, in other embodiments from about 2:1 to about 500:1, and in other embodiments from about 5:1 to about 200:1. In an embodiment, the halogen / Ln molarP22296WO1A; BSP183WO ratio can be varied from about 0.5:1 to about 20:1, in other embodiments from about 1:1 to about 10:1, and in other embodiments from about 2:1 to about 6:1.

[0048] In yet another embodiment, the molar ratio of the non-coordinating anion or non-coordinating anion precursor to the lanthanide-containing compound (An / Ln) may be from about 0.5:1 to about 20:1, in other embodiments from about 0.75:1 to about 10:1, and in other embodiments from about 1:1 to about 6:1.

[0049] The catalyst system can be formed by various methods. In an embodiment, the lanthanide-based catalyst composition may be preformed. That is, the catalyst ingredients are premixed outside the polymerization system. In an embodiment, the premixing of the catalyst ingredients forms an active catalyst system, which is a catalyst system capable of polymerizing monomer, especially conjugated diene monomer into the desired cis-1,4- polydienes desired by one or more embodiments of this invention. Examples of useful processes for preforming a lanthanide-based catalyst composition are disclosed in U.S. Pat. No.5,686,371, U.S. Pat. No.6,576,731, U.S. Pat. Pub. No.2002 / 0,035,226, U.S. Pat. Pub. No.2012 / 0,208,964, and U.S. Pat. Pub. No.2013 / 0,237,669, which are incorporated herein by reference.

[0050] In an embodiment, the catalyst system may be formed by combining the catalyst ingredients simultaneously or sequentially. Where the ingredients are combined sequentially, the alkylating agent can be first combined with the lanthanide-containing compound, and then the mixture can be combined with the halogen source or the compound containing a non-coordinating anion or the non- coordinating anion precursor. In other embodiments, the alkylating agent and the halogen source (or non- coordinating anion or non-coordinating anion precursor) can first be combined, and then the mixture can be combined with the lanthanide-containing compound. In yet other embodiments, the lanthanide-containing compound and the halogen source (or non-coordinating anion or non-coordinating anion precursor) can first be combined, and then the mixture can be combined with the alkylating agent.

[0051] In an embodiment, the preformation of the catalyst may take place with a solvent. In an embodiment, a solvent may be employed as a carrier to either dissolveP22296WO1A; BSP183WO or suspend the catalyst in order to facilitate the delivery of the catalyst to the polymerization system. In other embodiments, monomer can be used as the carrier. In yet other embodiments, the catalyst can be used in a neat state without any solvent.

[0052] In an embodiment, suitable solvents include those organic compounds that will not undergo polymerization or incorporation into propagating polymer chains during the polymerization of monomer in the presence of the catalyst or initiator. In an embodiment, these organic species are liquid at ambient temperature and pressure. In an embodiment, these organic solvents are inert to the catalyst or initiator. Exemplary organic solvents include hydrocarbons with a low or relatively low boiling point such as aromatic hydrocarbons, aliphatic hydrocarbons, and cycloaliphatic hydrocarbons. Non- limiting examples of aromatic hydrocarbons include benzene, toluene, xylenes, ethylbenzene, diethylbenzene, and mesitylene. Non- limiting examples of aliphatic hydrocarbons include n-pentane, n-hexane, n-heptane, n- octane, n-nonane, n-decane, isopentane, isohexanes, isopentanes, isooctanes, 2,2- dimethylbutane, petroleum ether, kerosene, and petroleum spirits. And, non-limiting examples of cycloaliphatic hydrocarbons include cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane. Mixtures of the above hydrocarbons may also be used. Aliphatic and cycloaliphatic hydrocarbons may be desirably employed for environmental reasons. The low-boiling hydrocarbon solvents are typically separated from the polymer upon completion of the polymerization.

[0053] Other examples of organic solvents include high-boiling hydrocarbons of high molecular weights, including hydrocarbon oils that are commonly used to oil- extend polymers. Examples of these oils include paraffinic oils, aromatic oils, naphthenic oils, vegetable oils other than castor oils, and low PCA oils including MES, TDAE, SRAE, heavy naphthenic oils and mixtures thereof. Since these hydrocarbons are non-volatile, they may not require separation and may remain incorporated in the polymer.

[0054] In an embodiment, the catalyst system may optionally be prepared in the presence of a small amount of an alkene containing compound, which may serve to stabilize the catalyst system. Useful alkene containing compounds may includeP22296WO1A; BSP183WO monomer as defined herein. Specific examples of suitable monomers for preforming the catalyst system include conjugated diene monomers such as 1,3-butadiene or isoprene. The amount of alkene containing compound that may be used for preforming the catalyst can be about 1 to about 100 moles, in other embodiments about 2.5 to about 75 moles, and in other embodiments about 5 to about 50 moles per mole of the lanthanide-containing compound.

[0055] In an embodiment, the catalyst systems may be prepared at specific temperatures. For example, the catalyst compositions can be prepared at a temperature of at least -20° C, at least 0° C, at least 20° C, or at least 40° C. In these or other embodiments, the catalyst compositions can be prepared at a temperature of at most 100° C, at most 80° C, at most 60° C, at most 40° C, at most 20° C, or at most 0° C.

[0056] In an embodiment, the catalyst composition may be aged prior to use (i.e., prior to being added to the polymerization system). In an embodiment, the catalyst composition may be aged at a temperature of at least -20° C, for example, at least 0° C, at least 20° C, or at least 40° C. In these or other embodiments, the catalyst compositions may be aged at a temperature of at most 100° C, for example, at most 80° C, in other embodiments at most 60° C, in other embodiments at most 40° C, in other embodiments at most 20° C, and in other embodiments at most 0° C. In certain embodiments, the catalyst composition may be aged in an environment without temperature control, where the catalyst composition would potentially be subject to varying environmental temperatures. In these or other embodiments, the catalyst composition may be aged at a temperature as described above and further aged, for at least a portion of the aging time, at an uncontrolled temperature.

[0057] In an embodiment, the catalyst composition may be aged for at least 1 hour, at least 3 hours, at least 6 hours, at least 12 hours, at least 24 hours, at least 3 days, at least 5 days, at least 6 days, at least 12 days, at least 30 days, or at least 60 days. In an embodiment, the catalyst composition may be aged for at most 1000 days, at most 750 days, at most 500 days, at most 300 days, at most 100 days, at most 24 days, atP22296WO1A; BSP183WO most 18 days, or at most 12 days. In an embodiment, the catalyst composition is aged about 4 to about 16 days, about 5 to about 15 days, or about 6 to about 12 days.

[0058] In an embodiment, additional alkylating agent (e.g., additional alkyl aluminum hydride) is added to the catalyst composition after the catalyst composition has been aged. The addition of alkylating agent allows for the tailoring of properties, such as the Mooney viscosity of the polymer synthesized by using the catalyst composition. This may be beneficial because higher Mooney viscosities have been observed when employing aged catalyst compositions. In an embodiment, this additional alkylating agent is introduced to the catalyst composition prior to introducing the catalyst composition to the monomer to be polymerized (i.e. they are premixed prior to being added to the polymerization system). In other embodiments, the aged catalyst composition and the alkylating agent are added individually, either simultaneously or sequentially, to the monomer to be polymerized (i.e. the polymerization system).

[0059] The amount of alkylating agent added can vary based upon factors such as the amount of alkylating agent present within the original catalyst composition, the length of time the catalyst is aged, the temperature at which aging took place, and the desired Mooney viscosity. In an embodiment, the amount of additional alkylating agent added to the catalyst composition may be described with reference to the amount of lanthanide-containing compound within the catalyst composition. In an embodiment, the molar ratio of the additional alkylating agent added after aging to the lanthanide- containing compound within the catalyst composition (alkylating agent / Ln) can be at least 0.1:1, in other embodiments at least 0.5:1, in other embodiments at least 1:1, and in other embodiments at least 5:1. In these or other embodiments, the molar ratio of the additional alkylating agent added after aging to the lanthanide-containing compound within the catalyst composition (alkylating agent / Ln) can be the varied from about 0.1:1 to about 100:1, in other embodiments from about 0.5:1 to about 50: 1, and in other embodiments from about 0.8:1 to about 20:1. In or more embodiments, the amount of additional alkylating agent added after aging is that amount sufficient toP22296WO1A; BSP183WO produce a polydienes having a Mooney viscosity (ML 1 +4 @ 100 °C) of from about 10 to about 100, in other embodiments from about 20 to about 90, and in other embodiments from about 25 to about 85. In an embodiment, the amount of additional alkylating agent added after aging is that amount sufficient to produce a polydiene having a Mooney viscosity that is generally similar to that Mooney viscosity that would have been achieved with the same catalyst system without aging the catalyst.

[0060] In an embodiment, the catalyst composition, with the additional alkylating agent included therein, is introduced to monomer to be polymerized within 1 minute, within 15 minutes, within 1 hour, or within 24 hours of introducing the additional alkylating agent.

[0061] In an embodiment, the catalyst employed herein is a preformed catalyst that is the combination or reaction product of a lanthanide carboxylate, an aluminum hydride, and an organometallic halide. In an embodiment, the catalyst system may have an aluminum hydride to lanthanide carboxylate molar ratio, which is best described as a molar ratio of the moles of aluminum metal atoms in the aluminum hydride to the moles of lanthanide atoms in the lanthanide carboxylate (Al / Ln) of less than 1000:1, such as less than 500:1, or less than 200:1. In these or other embodiments, the catalyst system may have an aluminum hydride to lanthanide carboxylate molar ratio (Al / Ln) of greater than 1:1, greater than 2:1, or greater than 5:1. In certain embodiments, the catalyst system may have an aluminum hydride to lanthanide carboxylate molar ratio (Al / Ln) that is about 1:1 to about 1000:1, about 2:1 to about 500:1, or about 5:1 to about 200:1.

[0062] In those embodiments where both an aluminoxane and at least one other organoaluminum agent are employed as alkylating agents, the molar ratio of the aluminoxane to the lanthanide-containing compound (aluminoxane / Ln) can be 5:1 to about 1,000:1, such as about 10:1 to about 700:1, or 20:1 to about 500:1; and the molar ratio of the at least one other organoaluminum compound to the lanthanide-containing compound (Al / Ln) can be about 1:1 to about 200:1, about 2:1 to about 150:1, or about 5:1 to about 100:1.P22296WO1A; BSP183WO

[0063] In specific embodiments, the lanthanide carboxylate is a neodymium carboxylate, the aluminum hydride is a dihydrocarbylaluminum hydride, trihydrocarbylaluminum, and / or hydrocarbylaluminum dihydride, and the organometallic halide is a hydrocarbyl aluminum sesquichloride. In still more specific embodiments, the catalyst system is the combination or reaction product of a neodymium neodecanoate, diisobutylaluminum hydride, and ethylaluminum sesquichloride. The catalyst system may have a diisobutylaluminum hydride to neodymium neodecanoate molar ratio of about 5 to about 40, or in other embodiments about 10 to about 20, and an ethylaluminum sesquichloride to neodymium neodecanoate molar ratio, which is best described as a molar ratio of the moles of halogen atoms in the ethylaluminum sesquichloride to the moles of lanthanide atoms in the neodymium neodecanoate (halogen / Ln), of about 1 to about 4, or about 2.5 to about 3.5. In these or other embodiments, these specific catalyst systems may include a conjugated diene (such as 1,3-butadiene or isoprene) as a stabilizer.

[0064] Catalyst systems that may be employed, may be preformed catalyst systems available under the tradename COMCAT Nd-FC (NH), COMCAT Nd-FC / 20 (NH), COMCAT Nd-FC / SF [COMAR CHEMICALS (Pty) Ltd].

[0065] A method of making the functional polymer comprises the steps of: (a) preparing a catalyst composition by combining a lanthanide-containing compound, an alkylating agent, and a halogen source; (b) aging the catalyst composition to form an aged catalyst composition, where said step of aging includes aging for 5 days to 15 days; (c) combining the aged catalyst composition, additional alkylating agent, and conjugated diene monomer to be polymerized to form a polymerization system that produces a polydiene having a reactive chain end; and (d) introducing a functionalizing agent, such as a heteroarylcarbonitrile-containing agent, to the polymerization system to thereby prepare the functional polymer. A total amount of aluminum employed relative to a total amount of the conjugated diene monomer may be less than 5 mmol per 100 grams of the conjugated diene monomer. The step of combining includes combining about 0.001 to about 2 mmol of the lanthanide-containing compound per 100 grams of theP22296WO1A; BSP183WO conjugated diene monomer to be polymerized. Furthermore details on the process of making the functional polymer are in U.S.2023 / 0183399, incorporated herein by reference.

[0066] The functional polymer of this disclosure comprises a high 1,4-cis butadiene rubber (BR) functionalized at one or more ends with a functional group that is reactive to carbon black. In an embodiment, the 1,4-cis content of the BR is about 90% or greater, such as about 95% to about 99.9%, or about 97% to about 99%. The functional polymer may have a Tg of less than -101 °C (e.g., - 101, -102, -103, -104, -105, -106, -107, -108, -109, -110, -111, -112, etc. °C), such as -101 to -110 °C (e.g., -101, -102, -103, -104, -105, -106, -107, -108, -109, -110 °C).

[0067] In one or more embodiments, the number average molecular weight (Mn) of the functional polymer may be about 50,000 to about 1,000,000, in other embodiments about 100,000 to 400,000, in other embodiments from about 125,000 to about 300,000, and in other embodiments about 150,000 to about 200,000, as determined by using gel permeation chromatography (GPC) calibrated with polystyrene standards and Mark-Houwink constants for the polymer in question. The molecular weight distribution or polydispersity (Mw / Mn) of the functional polymer of this disclosure may be from about 1.5 to about 5.0, and in other embodiments from about 2.0 to about 4.0. In these or other embodiments, the functional polymer may have a Mw / Mn of less than 3.0, in other embodiments less than 2.5, in other embodiments less than 2.3, in other embodiments less than 2.2, in other embodiments less than 2.1, and in other embodiments less than 2.0.

[0068] In certain embodiments, the Mw of the functional polymer, may be about 80,000 to about 1,500,000 grams / mole or about 125,000 to about 900,000 grams / mole, such as, about 200,000 to about 650,000, or about 250,000 to about 550,000 grams / mole, or about 350,000 to about 525,000 according to a polystyrene standard (and as determined by GPC).

[0069] It should be understood that the foregoing Mw and Mn values refer to coupled Mw and coupled Mn rather than base polymer values. In certainP22296WO1A; BSP183WO embodiments, the functional polymer, as described above, has a Mn within one of the foregoing ranges in combination with a Mw within one of the foregoing ranges, optionally in combination with a Mw / Mn value as discussed below.

[0070] In an embodiment, the functional group is a heteroarylcarbonitrile molecule, such as, for example, pyrazinecarbonitrile. In an embodiment, the modification efficiency is about 30% or greater, (i.e. about 30% or more of the polymer chain ends of the BR polymer are functionalized). For example, the modification efficiency may be about 40% or more, such as, about 45% to about 90%, or about 50% to about 65%. In an embodiment, the nitrogen content of the functional polymer is 0.3 to 5, such as 0.5 to 2.5, or 1. to 2 N atoms per polymer chain (number average). In an embodiment, the nitrogen content of the functional polymer is 50 to 500 ppm, such as, 75 to 400 ppm, or 100 to 300 ppm, or 175 to 275 ppm.

[0071] In an embodiment, the functional polymer is not functionalized with any siloxy-group containing compound. In an embodiment, the functional polymer is not functionalized with a silica-reactive functional group.

[0072] In an exemplary polymerization process the polymerization is catalyzed or initiated by a lanthanide-based system or an anionic initiator, one or more of the resulting polymer chains possess reactive ends. In an embodiment, the catalyst is exclusive of MAO.

[0073] The chain ends may be either pseudo-living or living before the polymerization mixture is quenched. The reactive polymer may be referred to as a pseudo-living polymer where a coordination catalyst is employed or as a living polymer where an anionic initiator is employed. In an embodiment, a polymerization mixture including reactive polymer may be referred to as an active polymerization mixture. The percentage of polymer chains possessing a reactive end depends on various factors such as the type of catalyst or initiator, the type of monomer, the purity of the ingredients, the polymerization temperature, the monomer conversion, and many other factors.

[0074] In an embodiment, at least about 20% of the polymer chains possess a reactive end, in another embodiment at least about 30% of the polymer chains possessP22296WO1A; BSP183WO a reactive end, in other embodiments at least about 40% of the polymer chains possess a reactive chain end, in another embodiment at least about 50% of the polymer chains possess a reactive end, and in still other embodiments at least about 80% of the polymer chains possess a reactive end. In any event, the reactive polymer can be reacted with heterocyclic nitrile compounds or mixtures thereof to form the functionalized BR polymer described herein.

[0075] In an embodiment, heterocyclic nitrile compounds include at least one — C≡N group (i.e., cyano or nitrile group) and at least one heterocyclic group. In particlular embodiments, at least one cyano group is directly attached to a heterocyclic group. In these or other embodiments, at least one cyano group is indirectly attached to a heterocyclic group.

[0076] In an embodiment, heterocyclic nitrile compounds may be represented by the formula θ-C≡N, where θ represents a heterocyclic group. In other embodiments, heterocyclic nitrile compounds may be represented by the formula θ-R—C≡N, where θ represents a heterocyclic group and R represents a divalent organic group.

[0077] In an embodiment, divalent organic groups may include hydrocarbylene groups or substituted hydrocarbylene groups such as, but not limited to, alkylene, cycloalkylene, substituted alkylene, substituted cycloalkylene, alkenylene, cycloalkenylene, substituted alkenylene, substituted cycloalkenylene, arylene, and substituted arylene groups. In an embodiment, each group may contain from 1 carbon atom, or the appropriate minimum number of carbon atoms to form the group, up to about 20 carbon atoms. Substituted hydrocarbylene groups include a hydrocarbylene groups in which one or more hydrogen atoms have been replaced by a substituent such as an alkyl group. The divalent organic groups may also contain one or more heteroatoms such as, but not limited to, nitrogen, oxygen, boron, silicon, sulfur, tin, and phosphorus atoms.

[0078] In an embodiment, θ may contain one or more additional cyano groups (i.e., —C≡N), and as a result the heterocyclic nitrile compounds may therefore contain two or more cyano groups. In these or other embodiments, the heterocyclic group mayP22296WO1A; BSP183WO contain unsaturation and may be aromatic or non-aromatic. The heterocyclic group may contain one heteroatom or multiple heteroatoms that are either the same or distinct. In particular embodiments, the heteroatoms may be selected from the group consisting of nitrogen, oxygen, sulfur, boron, silicon, tin, and phosphorus atoms. Also, the heterocyclic group may be monocyclic, bicyclic, tricyclic or multicyclic.

[0079] Representative examples of heterocyclic groups containing one or more nitrogen heteroatoms include 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrazinyl, 2-pyrimidinyl, 4- pyrimidinyl, 5-pyrimidinyl, 3-pyridazinyl, 4-pyridazinyl, N-methyl-2-pyrrolyl, N-methyl-3- pyrrolyl, N-methyl-2-imidazolyl, N-methyl-4-imidazolyl, N-methyl-5-imidazolyl, N- methyl-3-pyrazolyl, N-methyl-4-pyrazolyl, N-methyl-5-pyrazolyl, N-methyl-1,2,3-triazol- 4-yl, N-methyl-1,2,3-triazol-5-yl, N-methyl-1,2,4-triazol-3-yl, N-methyl-1,2,4-triazol-5-yl, 1,2,4-triazin-3-yl, 1,2,4-triazin-5-yl, 1,2,4-triazin-6-yl, 1,3,5-triazinyl, N-methyl-2-pyrrolin- 2-yl, N-methyl-2-pyrrolin-3-yl, N-methyl-2-pyrrolin-4-yl, N-methyl-2-pyrrolin-5-yl, N- methyl-3-pyrrolin-2-yl, N-methyl-3-pyrrolin-3-yl, N-methyl-2-imidazolin-2-yl, N-methyl- 2-imidazolin-4-yl, N-methyl-2-imidazolin-5-yl, N-methyl-2-pyrazolin-3-yl, N-methyl-2- pyrazolin-4-yl, N-methyl-2-pyrazolin-5-yl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, N-methylindol-2-yl, N-methylindol-3-yl, N-methylisoindol-1- yl, N-methylisoindol-3-yl, 1-indolizinyl, 2-indolizinyl, 3-indolizinyl, 1-phthalazinyl, 2- quinazolinyl, 4-quinazolinyl, 2-quinoxalinyl, 3-cinnolinyl, 4-cinnolinyl, 1-methylindazol-3- yl, 1,5-naphthyridin-2-yl, 1,5-naphthyridin-3-yl, 1,5-naphthyridin-4-yl, 1,8-naphthyridin- 2-yl, 1,8-naphthyridin-3-yl, 1,8-naphthyridin-4-yl, 2-pteridinyl, 4-pteridinyl, 6-pteridinyl, 7-pteridinyl, 1-methylbenzimidazol-2-yl, 6-phenanthridinyl, N-methyl-2-purinyl, N- methyl-6-purinyl, N-methyl-8-purinyl, N-methyl-β-carbolin-1-yl, N-methyl-β-carbolin-3- yl, N-methyl-β-carbolin-4-yl, 9-acridinyl, 1,7-phenanthrolin-2-yl, 1,7-phenanthrolin-3-yl, 1,7-phenanthrolin-4-yl, 1,10-phenanthrolin-2-yl, 1,10-phenanthrolin-3-yl, 1,10- phenanthrolin-4-yl, 4,7-phenanthrolin-1-yl, 4,7-phenanthrolin-2-yl, 4,7-phenanthrolin-3- yl, 1-phenazinyl, 2-phenazinyl, pyrrolidino, and piperidino groups.

[0080] Representative examples of heterocyclic groups containing one or more oxygen heteroatoms include 2-furyl, 3-furyl, 2-benzo[b]furyl, 3-benzo[b]furyl, 1-P22296WO1A; BSP183WO isobenzo[b]furyl, 3-isobenzo[b]furyl, 2-naphtho[2,3-b]furyl, and 3-naphtho[2,3-b]furyl groups.

[0081] Representative examples of heterocyclic groups containing one or more sulfur heteroatoms include 2-thienyl, 3-thienyl, 2-benzo[b]thienyl, 3-benzo[b]thienyl, 1- isobenzo[b]thienyl, 3-isobenzo[b]thienyl, 2-naphtho[2,3-b]thienyl, and 3-naphtho[2,3- b]thienyl groups.

[0082] Representative examples of heterocyclic groups containing two or more distinct heteroatoms include 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, 5- isothiazolyl, 1,2,3-oxadiazol-4-yl, 1,2,3-oxadiazol-5-yl, 1,3,4-oxadiazol-2-yl, 1,2,3- thiadiazol-4-yl, 1,2,3-thiadiazol-5-yl, 1,3,4-thiadiazol-2-yl, 2-oxazolin-2-yl, 2-oxazolin-4-yl, 2-oxazolin-5-yl, 3-isoxazolinyl, 4-isoxazolinyl, 5-isoxazolinyl, 2-thiazolin-2-yl, 2-thiazolin- 4-yl, 2-thiazolin-5-yl, 3-isothiazolinyl, 4-isothiazolinyl, 5-isothiazolinyl, 2-benzothiazolyl, and morpholino groups.

[0083] Representative examples of heterocyclic nitrile compounds defined by the formula θ-C≡N, where θ contains one or more nitrogen heteroatoms, include 2- pyridinecarbonitrile, 3-pyridinecarbonitrile, 4-pyridinecarbonitrile, pyrazinecarbonitrile, 2-pyrimidinecarbonitrile, 4-pyrimidinecarbonitrile, 5-pyrimidinecarbonitrile, 3- pyridazinecarbonitrile, 4-pyridazinecarbonitrile, N-methyl-2-pyrrolecarbonitrile, N- methyl-3-pyrrolecarbonitrile, N-methyl-2-imidazolecarbonitrile, N-methyl-4- imidazolecarbonitrile, N-methyl-5-imidazolecarbonitrile, N-methyl-3- pyrazolecarbonitrile, N-methyl-4-pyrazolecarbonitrile, N-methyl-5-pyrazolecarbonitrile, N-methyl-1,2,3-triazole-4-carbonitrile, N-methyl-1,2,3-triazole-5-carbonitrile, N-methyl- 1,2,4-triazole-3-carbonitrile, N-methyl-1,2,4-triazole-5-carbonitrile, 1,2,4-triazine-3- carbonitrile, 1,2,4-triazine-5-carbonitrile, 1,2,4-triazine-6-carbonitrile, 1,3,5- triazinecarbonitrile, N-methyl-2-pyrroline-2-carbonitrile, N-methyl-2-pyrroline-3- carbonitrile, N-methyl-2-pyrroline-4-carbonitrile, N-methyl-2-pyrroline-5-carbonitrile, N- methyl-3-pyrroline-2-carbonitrile, N-methyl-3-pyrroline-3-carbonitrile, N-methyl-2- imidazoline-2-carbonitrile, N-methyl-2-imidazoline-4-carbonitrile, N-methyl-2-P22296WO1A; BSP183WO imidazoline-5-carbonitrile, N-methyl-2-pyrazoline-3-carbonitrile, N-methyl-2-pyrazoline- 4-carbonitrile, N-methyl-2-pyrazoline-5-carbonitrile, 2-quinolinecarbonitrile, 3- quinolinecarbonitrile, 4-quinolinecarbonitrile, 1-isoquinolinecarbonitrile, 3- isoquinolinecarbonitrile, 4-isoquinolinecarbonitrile, N-methylindole-2-carbonitrile, N- methylindole-3-carbonitrile, N-methylisoindole-1-carbonitrile, N-methylisoindole-3- carbonitrile, 1-indolizinecarbonitrile, 2-indolizinecarbonitrile, 3-indolizinecarbonitrile, 1- phthalazinecarbonitrile, 2-quinazolinecarbonitrile, 4-quinazolinecarbonitrile, 2- quinoxalinecarbonitrile, 3-cinnolinecarbonitrile, 4-cinnolinecarbonitrile, 1- methylindazole-3-carbonitrile, 1,5-naphthyridine-2-carbonitrile, 1,5-naphthyridine-3- carbonitrile, 1,5-naphthyridine-4-carbonitrile, 1,8-naphthyridine-2-carbonitrile, 1,8- naphthyridine-3-carbonitrile, 1,8-naphthyridine-4-carbonitrile, 2-pteridinecarbonitrile, 4-pteridinecarbonitrile, 6-pteridinecarbonitrile, 7-pteridinecarbonitrile, 1- methylbenzimidazole-2-carbonitrile, phenanthridine-6-carbonitrile, N-methyl-2- purinecarbonitrile, N-methyl-6-purinecarbonitrile, N-methyl-8-purinecarbonitrile, N- methyl-β-carboline-1-carbonitrile, N-methyl-β-carboline-3-carbonitrile, N-methyl-β- carboline-4-carbonitrile, 9-acridinecarbonitrile, 1,7-phenanthroline-2-carbonitrile, 1,7- phenanthroline-3-carbonitrile, 1,7-phenanthroline-4-carbonitrile, 1,10-phenanthroline- 2-carbonitrile, 1,10-phenanthroline-3-carbonitrile, 1,10-phenanthroline-4-carbonitrile, 4,7-phenanthroline-1-carbonitrile, 4,7-phenanthroline-2-carbonitrile, 4,7- phenanthroline-3-carbonitrile, 1-phenazinecarbonitrile, 2-phenazinecarbonitrile, 1- pyrrolidinecarbonitrile, and 1-piperidinecarbonitrile.

[0084] Representative examples of heterocyclic nitrile compounds defined by the formula θ-C≡N, where θ contains one or more oxygen heteroatoms, include 2- furonitrile, 3-furonitrile 2-benzo[b]furancarbonitrile, 3-benzo[b]furancarbonitrile, isobenzo[b]furan-1-carbonitrile, isobenzo[b]furan-3-carbonitrile, naphtho[2,3-b]furan-2- carbonitrile, and naphtho[2,3-b]furan-3-carbonitrile.

[0085] Representative examples of heterocyclic nitrile compounds defined by the formula θ-C≡N, where θ contains one or more sulfur heteroatoms, include 2- thiophenecarbonitrile, 3-thiophenecarbonitrile, benzo[b]thiophene-2-carbonitrile,P22296WO1A; BSP183WO benzo[b]thiophene-3-carbonitrile, isobenzo[b]thiophene-1-carbonitrile, isobenzo[b]thiophene-3-carbonitrile, naphtho[2,3-b]thiophene-2-carbonitrile, and naphtho[2,3-b]thiophene-3-carbonitrile.

[0086] Representative examples of heterocyclic nitrile compounds defined by the formula θ-C≡N, where θ contains two or more distinct heteroatoms, include 2- oxazolecarbonitrile, 4-oxazolecarbonitrile, 5-oxazolecarbonitrile, 3-isoxazolecarbonitrile, 4-isoxazolecarbonitrile, 5-isoxazolecarbonitrile, 2-thiazolecarbonitrile, 4- thiazolecarbonitrile, 5-thiazolecarbonitrile, 3-isothiazolecarbonitrile, 4- isothiazolecarbonitrile, 5-isothiazolecarbonitrile, 1,2,3-oxadiazole-4-carbonitrile, 1,2,3- oxadiazole-5-carbonitrile, 1,3,4-oxadiazole-2-carbonitrile, 1,2,3-thiadiazole-4- carbonitrile, 1,2,3-thiadiazole-5-carbonitrile, 1,3,4-thiadiazole-2-carbonitrile, 2- oxazoline-2-carbonitrile, 2-oxazoline-4-carbonitrile, 2-oxazoline-5-carbonitrile, 3- isoxazolinecarbonitrile, 4-isoxazolinecarbonitrile, 5-isoxazolinecarbonitrile, 2-thiazoline- 2-carbonitrile, 2-thiazoline-4-carbonitrile, 2-thiazoline-5-carbonitrile, 3- isothiazolinecarbonitrile, 4-isothiazolinecarbonitrile, 5-isothiazolinecarbonitrile, benzothiazole-2-carbonitrile, and 4-morpholinecarbonitrile.

[0087] Representative examples of heterocyclic nitrile compounds defined by the formula θ-C≡N, where θ contains one or more cyano groups include 2,3- pyridinedicarbonitrile, 2,4-pyridinedicarbonitrile, 2,5-pyridinedicarbonitrile, 2,6- pyridinedicarbonitrile, 3,4-pyridinedicarbonitrile, 2,4-pyrimidinedicarbonitrile, 2,5- pyrimidinedicarbonitrile, 4,5-pyrimidinedicarbonitrile, 4,6-pyrimidinedicarbonitrile, 2,3- pyrazinedicarbonitrile, 2,5-pyrazinedicarbonitrile, 2,6-pyrazinedicarbonitrile, 2,3- furandicarbonitrile, 2,4-furandicarbonitrile, 2,5-furandicarbonitrile, 2,3- thiophenedicarbonitrile, 2,4-thiophenedicarbonitrile, 2,5-thiophenedicarbonitrile, N- methyl-2,3-pyrroledicarbonitrile, N-methyl-2,4-pyrroledicarbonitrile, N-methyl-2,5- pyrroledicarbonitrile, 1,3,5-triazine-2,4-dicarbonitrile, 1,2,4-triazine-3,5-dicarbonitrile, 1,2,4-triazine-3,6-dicarbonitrile, 2,3,4-pyridinetricarbonitrile, 2,3,5- pyridinetricarbonitrile, 2,3,6-pyridinetricarbonitrile, 2,4,5-pyridinetricarbonitrile, 2,4,6- pyridinetricarbonitrile, 3,4,5-pyridinetricarbonitrile, 2,4,5-pyrimidinetricarbonitrile,P22296WO1A; BSP183WO 2,4,6-pyrimidinetricarbonitrile, 4,5,6-pyrimidinetricarbonitrile, pyrazinetricarbonitrile, 2,3,4-furantricarbonitrile, 2,3,5-furantricarbonitrile, 2,3,4-thiophenetricarbonitrile, 2,3,5-thiophenetricarbonitrile, N-methyl-2,3,4-pyrroletricarbonitrile, N-methyl-2,3,5- pyrroletricarbonitrile, 1,3,5-triazine-2,4,6-tricarbonitrile, and 1,2,4-triazine-3,5,6- tricarbonitrile.

[0088] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more nitrogen heteroatoms, include 2- pyridylacetonitrile, 3-pyridylacetonitrile, 4-pyridylacetonitrile, pyrazinylacetonitrile, 2- pyrimidinylacetonitrile, 4-pyrimidinylacetonitrile, 5-pyrimidinylacetonitrile, 3- pyridazinylacetonitrile, 4-pyridazinylacetonitrile, N-methyl-2-pyrrolylacetonitrile, N- methyl-3-pyrrolylacetonitrile, N-methyl-2-imidazolylacetonitrile, N-methyl-4- imidazolylacetonitrile, N-methyl-5-imidazolylacetonitrile, N-methyl-3- pyrazolylacetonitrile, N-methyl-4-pyrazolylacetonitrile, N-methyl-5-pyrazolylacetonitrile, 1,3,5-triazinylacetonitrile, 2-quinolylacetonitrile, 3-quinolylacetonitrile, 4- quinolylacetonitrile, 1-isoquinolylacetonitrile, 3-isoquinolylacetonitrile, 4- isoquinolylacetonitrile, 1-indolizinylacetonitrile, 2-indolizinylacetonitrile, 3- indolizinylacetonitrile, 1-phthalazinylacetonitrile, 2-quinazolinylacetonitrile, 4- quinazolinylacetonitrile, 2-quinoxalinylacetonitrile, 3-cinnolinylacetonitrile, 4- cinnolinylacetonitrile, 2-pteridinylacetonitrile, 4-pteridinylacetonitrile, 6- pteridinylacetonitrile, 7-pteridinylacetonitrile, 6-phenanthridinylacetonitrile, N-methyl- 2-purinylacetonitrile, N-methyl-6-purinylacetonitrile, N-methyl-8-purinylacetonitrile, 9- acridinylacetonitrile, 1,7-phenanthrolin-2-ylacetonitrile, 1,7-phenanthrolin-3- ylacetonitrile, 1,7-phenanthrolin-4-ylacetonitrile, 1,10-phenanthrolin-2-ylacetonitrile, 1,10-phenanthrolin-3-ylacetonitrile, 1,10-phenanthrolin-4-ylacetonitrile, 4,7- phenanthrolin-1-ylacetonitrile, 4,7-phenanthrolin-2-ylacetonitrile, 4,7-phenanthrolin-3- ylacetonitrile, 1-phenazinylacetonitrile, 2-phenazinylacetonitrile, pyrrolidinoacetonitrile, and piperidinoacetonitrile.

[0089] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more oxygen heteroatoms, include 2-P22296WO1A; BSP183WO furylacetonitrile, 3-furylacetonitrile, 2-benzo[b]furylacetonitrile, 3- benzo[b]furylacetonitrile, 1-isobenzo[b]furylacetonitrile, 3-isobenzo[b]furylacetonitrile, 2-naphtho[2,3-b]furylacetonitrile, and 3-naphtho[2,3-b]furylacetonitrile.

[0090] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more sulfur heteroatoms, include 2- thienylacetonitrile, 3-thienylacetonitrile, 2-benzo[b]thienylacetonitrile, 3- benzo[b]thienylacetonitrile, 1-isobenzo[b]thienylacetonitrile, 3- isobenzo[b]thienylacetonitrile, 2-naphtho[2,3-b]thienylacetonitrile, and 3-naphtho[2,3- b]thienylacetonitrile.

[0091] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains two or more distinct heteroatoms, include 2- oxazolylacetonitrile, 4-oxazolylacetonitrile, 5-oxazolylacetonitrile, 3- isoxazolylacetonitrile, 4-isoxazolylacetonitrile, 5-isoxazolylacetonitrile, 2- thiazolylacetonitrile, 4-thiazolylacetonitrile, 5-thiazolylacetonitrile, 3- isothiazolylacetonitrile, 4-isothiazolylacetonitrile, 5-isothiazolylacetonitrile, 3- isoxazolinylacetonitrile, 4-isoxazolinylacetonitrile, 5-isoxazolinylacetonitrile, 3- isothiazolinylacetonitrile, 4-isothiazolinylacetonitrile, 5-isothiazolinylacetonitrile, 2- benzothiazolylacetonitrile, and morpholinoacetonitrile.

[0092] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more cyano groups, include 2,3- pyridinediacetonitrile, 2,4-pyridinediacetonitrile, 2,5-pyridinediacetonitrile, 2,6- pyridinediacetonitrile, 3,4-pyridinediacetonitrile, 2,4-pyrimidinediacetonitrile, 2,5- pyrimidinediacetonitrile, 4,5-pyrimidinediacetonitrile, 4,6-pyrimidinediacetonitrile, 2,3- pyrazinediacetonitrile, 2,5-pyrazinediacetonitrile, 2,6-pyrazinediacetonitrile, 2,3- furandiacetonitrile, 2,4-furandiacetonitrile, 2,5-furandiacetonitrile, 2,3- thiophenediacetonitrile, 2,4-thiophenediacetonitrile, 2,5-thiophenediacetonitrile, N- methyl-2,3-pyrrolediacetonitrile, N-methyl-2,4-pyrrolediacetonitrile, N-methyl-2,5- pyrrolediacetonitrile, 1,3,5-triazine-2,4-diacetonitrile, 1,2,4-triazine-3,5-diacetonitrile, 1,2,4-triazine-3,6-diacetonitrile, 2,3,4-pyridinetriacetonitrile, 2,3,5-P22296WO1A; BSP183WO pyridinetriacetonitrile, 2,3,6-pyridinetriacetonitrile, 2,4,5-pyridinetriacetonitrile, 2,4,6- pyridinetriacetonitrile, 3,4,5-pyridinetriacetonitrile, 2,4,5-pyrimidinetriacetonitrile, 2,4,6-pyrimidinetriacetonitrile, 4,5,6-pyrimidinetriacetonitrile, pyrazinetriacetonitrile, 2,3,4-furantriacetonitrile, 2,3,5-furantriacetonitrile, 2,3,4-thiophenetriacetonitrile, 2,3,5- thiophenetriacetonitrile, N-methyl-2,3,4-pyrroletriacetonitrile, N-methyl-2,3,5- pyrroletriacetonitrile, 1,3,5-triazine-2,4,6-triacetonitrile, and 1,2,4-triazine-3,5,6- triacetonitrile.

[0093] The amount of the heterocyclic nitrile compound that can be added to the polymerization mixture may depend on various factors including the type and amount of catalyst or initiator used to initiate the polymerization and the desired degree of functionalization. In an embodiment, where the reactive polymer is prepared by employing a lanthanide-based catalyst, the amount of the heterocyclic nitrile compound employed can be described with reference to the lanthanide metal of the lanthanide compound. For example, the molar ratio of the heterocyclic nitrile compound to the lanthanide metal may be from about 1:1 to about 200:1, in other embodiments from about 5:1 to about 150:1, and in other embodiments from about 10:1 to about 100:1.

[0094] In other embodiments, such as where the reactive polymer is prepared by using an anionic initiator, the amount of the heterocyclic nitrile compound employed can be described with reference to the amount of metal cation associated with the initiator. For example, where an organolithium initiator is employed, the molar ratio of the heterocyclic nitrile compound to the lithium metal may be from about 0.3:1 to about 2:1, in other embodiments from about 0.6:1 to about 1.5:1, and in other embodiments from 0.8:1 to about 1.2:1.

[0095] In an exemplary embodiment, the functionalized BR is a component in a rubber composition for tire treads. In an embodiment, the functionalized high-cis BR is a minor polymer component of the composition, present in an amount of 5 phr to 50 phr, such as, about 8 to about 45 phr, such as, about 10 phr to about 40 phr, or about 15 phr to about 40 phr. In other exemplary embodiments, the functionalized high-cis BR is notP22296WO1A; BSP183WO necessarily a minor polymer component of the composition, and is present in an amount of about 10 to about 60 phr, such as about 20 to about 55 phr, or about 25 phr to about 50 phr.

[0096] In an exemplary embodiment, the rubber composition is filled with predominantly carbon black filler. For example, the reinforcing filler component may include carbon black in a range of about 25 to about 70 phr, such as about 35 to about 60 phr, or about 40 to about 55 phr. In an embodiment, the reinforcing filler component may also include silica in a range of about 0.1 phr to about 40 phr, such as, for example, about 1 phr to about 25 phr, or about 2 phr to about 15 phr.

[0097] In an exemplary embodiment, the composition uses natural rubber and / or styrene-butadiene rubber (SBR) as additional rubber components in the formulation. In an embodiment, either SBR, natural rubber, polyisoprene, or some combination of these make up the majority rubber component. Other examples amounts and ratios of these rubber and filler components are disclosed below. In an embodiment, the SBR is functionalized with hexamethyleneimine (HMI).

[0098] The subject rubber compositions are used in preparing treads for tires, generally by a process which includes forming of a tread pattern by molding and curing one of the subject rubber compositions. Thus, the tire treads will contain a cured form of one of the tire tread rubber compositions. The tire tread rubber compositions may be present in the form of a tread which has been formed but not yet incorporated into a tire and / or they may be present in a tread which forms part of a tire.

[0099] The Tg of the overall rubber composition may be referred to as a compound Tg or as a rubber composition Tg. In certain embodiments, the rubber composition has a compound Tg of -40 to -100 °C (e.g., -40, -45, -50, -55, -60, -65, -70, - 75, -80, -85, -90, or -95 °C ), -50 to -98 °C (e.g. -52, -57, -62, -67, -73, -77, -82, -87, -92, or -97 °C ), -45 to -85 °C (e.g., -45, -48, -51, -54, -57, -60, -63, -66, -69, -72, -75, -78, -81, or - 84 °C ), -50 to -80 °C (e.g., -51, -55, -59, -63, -67, -71, -75, or -79°C) or a range within one of the foregoing ranges. The compound Tg of a rubber composition can be measured using a dynamic mechanical thermal spectrometer (such as the Gabo instrumentP22296WO1A; BSP183WO described below, operating in tension mode) generally following the guidelines of ASTM D5992-96 (2011) and using a temperature sweep (from -100 to 65 °C), under specified test conditions (i.e., frequency 52 Hz, static strain of 6%, dynamic strain of 0.1%, sample geometry 4.75 mm wide x 29 mm long x 2 mm deep), with the measurement made on the sample after curing for 33 minutes at 145 °C, and using a vibratory method to estimate the Tg from the curve that results.

[0100] The ingredients of the elastomer component include the functionalized polybutadiene rubber disclosed herein. The composition may include about 10 to about 60 phr of the functionalized BR (e.g., 15, 20, 25, 35, 45, 50, 55 phr), such as, about 20 to about 40 parts (e.g., 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39 phr). The functionalized BR has a cis bond content of at least about 95%, a Tg of less than about -101 °C (e.g., - 101, -102, -103, -104, -105, -106, -107, -108, -109, -110, -111, -112, etc. °C), or -101 to -110 °C (e.g., -101, -102, -103, -104, -105, - 106, -107, -108, -109, -110 °C).

[0101] The 100 parts of elastomer component may also further comprise about 40 phr to about 90 phr of the rubber component being selected from the group consisting of: natural rubber, polyisoprene, styrene-butadiene rubber, and combinations thereof. In an exemplary embodiment, the majority of the rubber component is selected from these rubber components. For example, the composition may comprise about 51 to about 90 phr (e.g., 52, 55, 60, 65, 70, 75, 80, 85, or 89 phr), such as about 55 to about 80 phr, or about 60 to about 75 phr of the natural rubber, polyisoprene, or styrene-butadiene rubber.

[0102] In an exemplary embodiment, the composition may comprise about about 40 to about 70 phr (e.g., 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, or 68 phr), such as about 45 to about 60 parts (e.g., 47, 49, 51, 53, 55, 57, or 59 phr), or about 50 to about 55 phr of at least one natural rubber or polyisoprene rubber.

[0103] In an exemplary embodiment, the composition may comprise at least one styrene-butadiene rubber having a Tg of about -10 to about -60 °C or -30 to -50 °C (e.g., 30, 30, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, or 50 °C). The at least one styrene-P22296WO1A; BSP183WO butadiene rubber may be present in the composition in an amount of about 5 phr to about 25 phr (e.g., 6, 9, 12, 15, 18, 21, or 23 phr)., such as, about 8 phr to 20 phr, or about 9 phr to about 17 phr. In certain embodiments, the elastomer component includes no more than 11 phr (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or even 0 parts) of styrene-butadiene rubber.

[0104] In certain embodiments the 100 parts of elastomer component consists essentially or consists only of the at least one styrene-butadiene rubber, as specified, the functionalized polybutadiene rubber, as specified), and the natural rubber or polyisoprene (as specified) in amounts as discussed above. In other embodiments, the 100 parts of elastomer component includes, in addition to these, one or more additional rubbers. When one or more additional rubbers (iii) are present, the amount will generally be limited to no more than about 20 parts (e.g., 20 parts, 15 parts, 10 parts, 5 parts, or less), such as no more than about 15 parts (e.g., 15 parts, 10 parts, 5 parts, or less), no more than about 9 parts (e.g., 9, 8, 7, 6, 5, 4, 3, 2, 1 or even 0 parts), or no more than 5 parts (e.g., 5 parts, 4 parts, 3 parts, 2 parts, 1 part, or less).

[0105] In certain embodiments, one or more additional rubbers (iii) are selected from diene monomer-containing rubbers; in certain such embodiments, the one or more additional rubbers (iv) are selected from the group consisting of styrene- isoprene rubber, butadiene-isoprene rubber, styrene-isoprene-butadiene rubber, butyl rubber (both halogenated and non-halogenated), ethylene-propylene rubber (EPR), ethylene- butylene rubber (EBR), ethylene-propylene-diene rubber (EPDM), and combinations thereof. In yet other embodiments, the one or more additional rubbers are selected from natural rubber, polyisoprene, or a combination thereof; one or more styrene- butadiene rubbers other than the styrene-butadiene rubber (i), e.g., a SBR having a Tg of greater than about -30 °C (e.g., -25 °C, -20 °C, -15 °C or higher) or having a Tg of less than about -50 °C (e.g., -55, -60°C or lower); or from a polybutadiene other than the functionalized polybutadiene, e.g., a polybutadiene having a low cis 1,-4 bond content (e.g., of less than about 50%, less than about 45%, less than about 40%, etc.), a non-functionalized polybutadiene rubber having a cis bond content of at least aboutP22296WO1A; BSP183WO 95% and a Tg of about -101 °C or lower, or a combination thereof; or a combination of the foregoing types of rubbers.

[0106] Tg values referred to herein for elastomers represent a Tg measurement made upon the elastomer without any oil-extension. In other words, for an oil- extended elastomer, the Tg values above refer to the Tg prior to oil extension or to a non-oil-extended version of the same elastomer. Elastomer or polymer Tg values may be measured using a differential scanning calorimeter (DSC) instrument, such as manufactured by TA Instruments (New Castle, Delaware), where the measurement is conducted using a temperature elevation of 10°C / minute after cooling at -120 °C. Thereafter, a tangent is drawn to the base lines before and after the jump of the DSC curve. The temperature on the DSC curve (read at the point corresponding to the middle of the two contact points) can be used as Tg.

[0107] In certain embodiments, the average Tg of the elastomer component is - about 70 to about -90 °C (e.g., -70, -71, -72, -73, -74, -75, -76, -77, -78, -79, -80, -81, - 82, -83, -84, -85, -86, -87, -88, -89, or -90 °C), such as about -75 to about -85 °C (e.g., - 75, -76, -77, -78, -79, -80, -81, -82, -83, -84, or -85 °C). The average Tg of the elastomer component can be calculated using the Tg of each rubber present in the 100 parts of elastomer component and accounting for their relative weight percentage. When one (or more) of the rubbers is oil-extended, only the amount of rubber (i.e., excluding any amount of oil) is utilized in calculating the average Tg of the elastomer component. When one (or more) of the rubbers is oil-extended, the Tg of the oil-extended rubber in its non-oil-extended form (i.e., rubber only) is utilized in calculating the average Tg of the elastomer component.

[0108] As mentioned above, the elastomer component of the tire tread rubber composition may include at least one styrene-butadiene rubber (i) having a Tg of about -25 to about -55 °C or about -30 to about -50 °C (e.g., -30, -31, -32, -33, -34, -35, -36, - 37, -38, -39, -40, -41, -42, -43, -44, -45, -46, -47, -48, -49, or -50 °C) and the elastomer component of the tire tread rubber composition may include a silica- or carbon black- reactive functional group, in an amount as discussed above. In certain embodiments,P22296WO1A; BSP183WO the at least one styrene- butadiene rubber (i) has a Tg of about -40 to about -50 or -40 to -50 °C (e.g., -40, -41, -42, -43, -44, -45, -46, -47, -48, -49, or -50 °C), in an amount as discussed above.

[0109] The styrene monomer content (i.e., weight percent of the polymer chain comprising styrene units as opposed to butadiene units) of the at least one styrene- butadiene rubber (i), as described above, may vary. In certain embodiments, the at least one styrene-butadiene rubber (i), as described above, has a styrene monomer content of about 20 to about 45% or 25 to 40% (e.g., 20%, 25%, 32%, 34%, or 36%) by weight of the total monomer content (i.e., 1,3-butadiene + styrene), including about 35 to about 40% by weight.

[0110] According to certain embodiments, the vinyl bond content (i.e., 1,2- microstructure) of the at least one styrene-butadiene rubber(i), as described above, may vary. In certain embodiments, the at least one styrene-butadiene rubber(i), as discussed above, has a vinyl bond content of about 15 to about 45%, about 20 to about 40% (e.g., 20%, 25%, 30%,35%, or 38%), or about 21 to about 26%.

[0111] The at least one styrene-butadiene rubber(i), as described above, may have a vinyl bond content within one of the foregoing ranges, optionally in combination with one or more of the Mw, Mn, and / or Mw / Mn ranges discussed below, and in certain embodiments optionally in combination with one of the styrene monomer contents discussed above. The vinyl bond contents referred to herein should be understood as being for the vinyl bond content in the butadiene portion of the styrene-butadiene rubber polymer chain, and can be determined by H1-NMR and C13- NMR (e.g., using a 300 MHz Gemini 300 NMR Spectrometer System (Varian)). The styrene contents disclosed herein can be determined using a similar method and the same instrumentation.

[0112] According to certain embodiments, the Mw of the at least one styrene- butadiene rubber (i), as described above, may vary. In certain embodiments disclosed herein, the at least one styrene-butadiene rubber (i) (as described above), has a Mw of about 250,000 to about 550,000 grams / mole or about 275,000 to about 500,000P22296WO1A; BSP183WO grams / mole (e.g., 300,000; 325,000; 350,000; 375,000; 400,000; 425,000; 450,000; 475,000; 500,000; 525,000; or 550,000 grams / mole), about 300,000 to about 500,000 or 300,000 to 500,000 grams / mole (e.g., 300,000; 325,000; 350,000; 375,000; 400,000; 425,000; 450,000; 475,000; or 500,000 grams / mole), or about 350,000 to about 450,000 or 350,000 to 450,000 grams / mole (e.g., 350,000; 375,000; 400,000; 425,000; or 450,000 grams / mole), according to a polystyrene standard (and as determined by GPC).

[0113] According to the embodiments disclosed herein, the Mn of the at least one styrene-butadiene rubber (i), as described above, may vary. In certain embodiments disclosed herein, the at least one styrene-butadiene rubber (i), as described above, has a Mn of about 140,000 to about 450,000 grams / mole or 150,000 to 450,000 grams / mole (e.g., 156,000; 275,000; 300,000; 325,000; 350,000; 375,000; 400,000; 425,000; or 450,000 grams / mole), or about 300,000 to about 400,000 grams / mole or 300,000 to 400,000 grams / mole (e.g., 300,000; 325,000; 350,000; 375,000; or 400,000 grams / mole), according to a polystyrene standard (and as determined by GPC). When the at least one styrene-butadiene rubber (i), as described above, is a functional polymer, it should be understood that the foregoing Mw and Mn values refer to coupled Mw and coupled Mn rather than base polymer values. In certain embodiments, the at least one styrene-butadiene rubber of (i), as described above, has a Mn within one of the foregoing ranges in combination with a Mw within one of the foregoing ranges, optionally in combination with a Mw / Mn value as discussed below.

[0114] The Mw / Mn of the at least one styrene-butadiene rubber (i), as described above, have a Mw / Mn (polydispersity) of about 1.2 to about 4.1 (e.g., 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2), such as about 1.5 to about 3.25, or about 2 to about 3. As mentioned above, in Mw or Mn ranges described above, such as in combination with one of the certain embodiments disclosed herein, the at least one styrene-butadiene rubber (i), as described above, has a Mw / Mn within one of the foregoing ranges, inP22296WO1A; BSP183WO combination with at least one of the Mw ranges Mw ranges and one of the Mn ranges described above.

[0115] In certain embodiments disclosed herein, the at least one styrene- butadiene rubber (i), as described above, is an oil-extended rubber, incorporating oil in an amount as discussed further below. In other embodiments disclosed herein, the at least one styrene-butadiene rubber (i), as described above, is a non oil-extended rubber (i.e., the SBR is not extended with any oil).

[0116] The at least one styrene-butadiene rubber, which may have a Tg of about -30 to about -50 °C, may have silica or carbon black-reactive functional group. Non-limiting examples of silica-reactive functional groups generally include nitrogen- containing functional groups, silicon-containing functional groups, oxygen- or sulfur- containing functional groups, and metal-containing functional groups, as discussed in more detail below. A carbon-black reactive functional group includes for example HMI.

[0117] When the at least one styrene-butadiene rubber (i), as described above, has a filler-reactive functional group, the functionalization can be achieved during preparation of the polymer by adding a functional group to one or both terminus of the polymer, by adding a functional group to the backbone of the poly (or a combination of the foregoing) or by coupling more than one polymer chains to a coupling agent, or by a combination thereof. Such effects can be achieved by treating a living polymer with coupling agents, functionalizing agents, or a combination thereof which serve to couple and / or functionalize other chains. In certain embodiments, the at least one styrene-butadiene rubber (i) having a silica- or carbon black-reactive functional group contains one or more functional groups but is not coupled (i.e., does not contain any separate coupling agent). Generally, a coupling agent and / or functionalizing agent can be used at various molar ratios. Alternatively, in certain embodiments, the functionalized styrene-butadiene rubber of may be silica-reactive or carbon black-reactive merely from the result of using a coupling agent. Although reference is made herein to the use of both coupling agents and functionalizing groups (and compounds used therefor), those skilled in the art appreciate that certainP22296WO1A; BSP183WO compounds may serve both functions. That is, certain compounds may both couple and provide the polymer chains with a functional group. Those skilled in the art also appreciate that the ability to couple polymer chains may depend upon the amount of coupling agent reacted with the polymer chains. For example, advantageous coupling may be achieved where the coupling agent is added in a one to one ratio between the equivalents of lithium on the initiator and equivalents of leaving groups (e.g., halogen atoms) on the coupling agent. Non-limiting examples of coupling agents include metal halides, metalloid halides, alkoxysilanes, alkoxystannanes, and combinations thereof. In embodiments, the at least one styrene-butadiene rubber (i) has a silica-reactive or carbon black reactive-functional group (as discussed further, infra, as functional groups) but does not include any coupling agent selected from the group consisting of metal halides, metalloid halides, alkoxysilanes, alkoxystannanes, and combinations thereof.

[0118] Non-limiting examples of nitrogen-containing functional groups that can be utilized in certain embodiments as a silica-reactive functional group in the at least one styrene-butadiene rubber (i) include, but are not limited to, a substituted or unsubstituted amino group, an amide residue, an isocyanate group, an imidazolyl group, an indolyl group, an imino group, a nitrile group, a pyridyl group, and a ketimine group. In certain embodiments, the at least one styrene-butadiene rubber (i) has a silica-reactive functional group including, an unsubstituted amino group, a substituted amino group, or substituted imino group. The foregoing substituted or unsubstituted amino group should be understood to include a primary alkylamine, a secondary alkylamine, or a cyclic amine, and an amino group derived from a substituted or unsubstituted imine. In certain embodiments, the at least one styrene- butadiene rubber (i) of the elastomer component comprises at one silica-reactive functional group selected from the foregoing list of nitrogen-containing functional groups.P22296WO1A; BSP183WO

[0119] In certain embodiments, the at least one styrene-butadiene rubber (i) includes a silica-reactive functional group from a compound which includes nitrogen in the form of an imino group. Such an imino-containing functional group may be added by reacting the active terminal of a polymer chain with a compound having the following formula (I): whereinare selected from a group having 1 to 18 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms) selected from the group consisting of an alkyl group, an allyl group, and an aryl group; m and n are integers of 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) and 1 to 3 (1, 2, or 3), respectively. Each of R, R’, R’’, and R’’’ are may be hydrocarbyl and contain no heteroatoms. In certain embodiments, each R and R’ are independently selected from an alkyl group having 1 to 6 carbon atoms (e.g., 1, 2, 3, 4, 5, or 6 carbon atoms), such as, 1 to 3 carbon atoms (e.g., 1, 2, or 3 carbon atoms). In certain embodiments, m is an integer of 2 to 6 (e.g., 2, 3, 4, 5, or 6), such as, 2 to 3. In certain embodiments, R’’’ is selected from an alkyl group having 1 to 6 carbon atoms (e.g., 1, 2, 3, 4, 5, or 6 carbon atoms), such as, 2 to 4 carbon atoms (e.g., 2, 3, or 4 carbon atoms). In certain embodiments, R’’ is selected from an alkyl group having 1 to 6 carbon atoms (e.g., 1, 2, 3, 4, 5, or 6 carbon atoms), such as, 1 to 3 carbon atoms (e.g., 1, 2, or 3 carbon atoms), or 1 carbon atom (e.g., methyl). In certain embodiments, n is 3 resulting in a compound with a trihydrocarboxysilane moiety such as a trialkoxysilane moiety. Non- limiting examples of compounds having an imino group and meeting formula (I) above, which are suitable for providing the silica-reactive functional group for the styrene- butadiene rubber of (i) include, but are not limited to, N-(1,3-dimethylbutylidene)-3- (triethoxysilyl)-1-propaneamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1- propaneamine, N-ethylidene-3-(triethoxysily1)-1-propaneamine, N-(1-P22296WO1A; BSP183WO methylpropylidene)-3-(triethoxysilyl)-1-propaneamine, and N-(4-N,N- dimethylaminobenzylidene )-3-( triethoxysilyl)-1-propaneamine.

[0120] Non-limiting examples of silicon-containing functional groups that can be utilized in certain embodiments as a silica-reactive functional group in the at least one styrene-butadiene rubber (i) include, but are not limited to, an organic silyl or siloxy group, and more precisely, such a functional group may be selected from an alkoxysilyl group, an alkylhalosilyl group, a siloxy group, an alkylaminosilyl group, and an alkoxyhalosilyl group. Optionally, the organic silyl or siloxy group may also contain one or more nitrogens. Suitable silicon-containing functional groups for use in functionalizing diene-based elastomers also include those disclosed in U.S. Patent No. 6,369,167, the entire disclosure of which is herein incorporated by reference. In certain embodiments, the at least one styrene-butadiene rubber (i) comprises at least one silica-reactive functional group selected from the foregoing list of silicon-containing functional groups.

[0121] In certain embodiments, the at least one styrene-butadiene rubber (i) includes a silica-reactive functional group which includes a silicon-containing functional group having a siloxy group (e.g., a hydrocarbyloxysilane-containing compound), wherein the compound optionally includes a monovalent group having at least one functional group. Such a silicon-containing functional group may be added by reacting the active terminal of a polymer chain with a compound having the following formula (II): wherein A1group having at least one functional group selected from epoxy, isocyanate, imine, cyano, carboxylic ester, carboxylic anhydride, cyclic tertiary amine, non-cyclic tertiary amine, pyridine, silazane and sulfide; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms); RdrepresentsP22296WO1A; BSP183WO a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms), a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms (e.g., 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms) or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms) or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms (e.g., 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms); b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof. As used herein, a partial condensation product refers to a product in which a part (not all) of a SiOR group in the hydrocarbyloxysilane compound is turned into a SiOSi bond by condensation. In certain embodiments, at least one of the following is met: (a) Rcrepresents a divalent hydrocarbon group having 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 2 to 3 carbon atoms (e.g., 2 or 3 carbon atoms); (b) Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 1 to 2 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 8 carbon atoms; (c) Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 1 to 2 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 8 carbon atoms; in certain such embodiments, each of (a), (b) and (c) are met and Rc, Reand Rdare selected from one of the foregoing groups.

[0122] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one epoxy group. Non-limiting specific examples of such compounds include 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, (2-glycidoxyethyl)methyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-P22296WO1A; BSP183WO glycidoxypropyltriethoxysilane, (3-glycidoxypropyl)-methyldimethoxysilane, 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl)ethyl(methyl)dimethoxysilane.

[0123] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one isocyanate group. Non-limiting specific examples of such compounds include 3-isocyanatopropyltrimethoxysilane, 3- isocyanatopropyltriethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, and 3- isocyanatopropyltriisopropoxysilane.

[0124] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one imine group. Non-limiting specific examples of such compounds include N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propaneamine, N-(1- methylethylidene)-3-(triethoxysilyl)-1-propaneamine, N-ethylidene-3-(triethoxysilyl)-1- propaneamine, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propaneamine, N-(4-N,N- dimethylaminobenzylidene)-3-(triethoxysilyl)-1-propaneamine, N-(cyclohexylidene)-3- (triethoxysilyl)-1-propaneamine and trimethoxysilyl compounds, methyldiethoxysilyl compounds, ethyldimethoxysilyl compounds and the like each corresponding to the above triethoxysilyl compounds. Among them, N-(1,3-dimethylbutylidene)-3- (triethoxysilyl)-1-propaneamine and N-(1-methylpropylidene)-3-(triethoxysilyl)-1- propaneamine are particularly suited. Also, the imine(amidine) group-containing compounds include 1-[3-trimethoxysilyl]propyl]-4,5-dihydroimidazole, 3-(1- hexamethyleneimino)propyl(triethoxy)silane, (1- hexamethyleneimino)methyl(trimethoxy)silane, N-(3-triethoxysilylpropyl)-4,5- dihydroimidazole, N-(3-isopropoxysilylpropyl)-4,5-dihydroimidazole, and N-(3- methyldiethoxysilylpropyl)-4,5-dihydroimidazole.

[0125] In certain embodiments, the silica-reactive functional group of the styrene- butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one carboxylic ester group. Non-limiting specific examples of such compoundsP22296WO1A; BSP183WO include 3-methacryloyloxypropyltriethoxysilane, 3- methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropyltriisopropoxysilane.

[0126] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one carboxylic anhydride group. Non-limiting specific examples of such compounds include 3-trimethoxysilylpropylsuccinic anhydride, 3- triethoxysilylpropylsuccinic anhydride, and 3-methyldiethoxysilylpropylsuccinic anhydride.

[0127] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one cyano group. Non-limiting specific examples of such compounds include 2-cyanoethylpropyltriethoxysilane.

[0128] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one cyclic tertiary amine group. Non-limiting specific examples of such compounds include 3-(1-hexamethyleneimino)propyltriethoxysilane, 3-(1- hexamethyleneimino)propyltrimethoxysilane, (1- hexamethyleneimino)methyltriethoxysilane, (1- hexamethyleneimino)methyltrimethoxysilane, 2-(1- hexamethyleneimino)ethyltriethoxysilane, 3-(1- hexamethyleneimino)ethyltrimethoxysilane, 3-(1-pyrrolidinyl)propyltrimethoxysilane, 3- (1-pyrrolidinyl)propyltriethoxysilane, 3-(1-heptamethyleneimino)propyltriethoxysilane, 3-(1-dodecamethyleneimino)propyltriethoxysilane, 3-(1- hexamethyleneimino)propyldiethoxymethylsilane, 3-(1- hexamethyleneimino)propyldiethoxyethylsilane, and 3-[10-(triethoxysilyl)decyl]-4- oxazoline.

[0129] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II)P22296WO1A; BSP183WO wherein A1has at least one non-cyclic tertiary amine group. Non-limiting specific examples of such compounds include 3-dimethylaminopropyltriethoxysilane, 3- dimethylaminopropyltrimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3- dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 2- dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyldiethoxymethylsilane, and 3-dibutylaminopropyltriethoxysilane.

[0130] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one pyridine group. Specific examples of such compounds include 2-trimethoxysilylethylpyridine.

[0131] In certain embodiments, the silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from a compound represented by Formula (II) wherein A1has at least one silazane group. Non-limiting specific examples of such compounds include N,N-bis(trimethylsilyl)-aminopropylmethyldimethoxysilane, 1- trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, N,N- bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N- bis(trimethylsilyl)aminopropyltriethoxysilane, N,N- bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N- bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N- bis(trimethylsilyl)aminoethyltriethoxysilane, N,N- bis(trimethylsilyl)aminoethylmethyldimethoxysilane, and N,N- bis(trimethylsilyl)aminoethylmethyldiethoxysilane.

[0132] In those embodiments wherein the at least one styrene-butadiene rubber has a silica-reactive functional group according to formula (II) wherein A1contains one or more protected nitrogens (as discussed in detail above), the nitrogen(s) may be deprotected or deblocked by hydrolysis or other procedures to convert the protected nitrogen(s) into a primary nitrogen. As a non-limiting example, a nitrogen bonded to two trimethylsilyl groups could be deprotected and converted to a primary amine nitrogen (such a nitrogen would still be bonded to the remainder of the formula (II) compound).P22296WO1A; BSP183WO Accordingly, in certain embodiments wherein a silica-reactive functional group of the at least one styrene-butadiene rubber (i) results from use of a compound according to formula (II) wherein A1contains one or more protected nitrogens, the functional polymer can be understood as containing a functional group resulting from a deprotected (or hydrolyzed) version of the compound.

[0133] Non-limiting examples of oxygen- or sulfur-containing functional groups as a silica-reactive functional group in the at least one styrene-butadiene rubber (i) include, but are not limited to, a hydroxyl group, a carboxyl group, an epoxy group, a glycidoxy group, a diglycidylamino group, a cyclic dithiane-derived functional group, an ester group, an aldehyde group, an alkoxy group, a ketone group, a thiocarboxyl group, a thioepoxy group, a thioglycidoxy group, a thiodiglycidylamino group, a thioester group, a thioaldehyde group, a thioalkoxy group, and a thioketone group. In certain embodiments, the foregoing alkoxy group may be an alcohol-derived alkoxy group derived from a benzophenone. In certain embodiments, the at least one styrene-butadiene rubber (i) comprises at least one silica-reactive functional group selected from the foregoing list of oxygen- or sulfur-containing functional groups.

[0134] In certain embodiments, the at least one styrene-butadiene rubber (i), whether having a silica-reactive functional group or not may be prepared by either solution polymerization or by emulsion polymerization. In certain embodiments, the only styrene-butadiene rubber(s) present as (i), whether having a silica-reactive functional group or not is (are) prepared by solution polymerization. In other embodiments, the only styrene-butadiene rubber(s) present as (i), whether having a silica-reactive functional group or not, is (are) prepared by emulsion polymerization. In certain embodiments, when more than one styrene-butadiene rubber is used for (i) or when more than one styrene-butadiene rubber having a silica-reactive functional group is used for (i), the rubbers are a combination of solution polymerized styrene-butadiene rubber and emulsion polymerized styrene-butadiene rubber (e.g., one solution styrene- butadiene rubber and one emulsion styrene-butadiene rubber). In certain embodiments, the only styrene-butadiene rubber(s) present in the elastomerP22296WO1A; BSP183WO component (including for the at least one styrene-butadiene rubber having a silica- reactive functional group) is (are) solution styrene-butadiene rubbers (i.e., no emulsion styrene-butadiene rubber is present).

[0135] In an embodiment, the at least one styrene-butadiene rubber (i), whether having a silica-reactive or carbon black-reactive functional group or not may be prepared by either solution polymerization or by emulsion polymerization. In certain embodiments, the only styrene-butadiene rubber(s) present as (i), whether having a silica-reactive or carbon black-reactive functional group or not is (are) prepared by solution polymerization. In other embodiments, the only styrene-butadiene rubber(s) present as (i), whether having a silica-reactive or carbon black-reactive functional group or not, is (are) prepared by emulsion polymerization. In certain embodiments, when more than one styrene-butadiene rubber is used for (i) or when more than one styrene- butadiene rubber having a silica-reactive or carbon black-reactive functional group is used for (i), the rubbers are a combination of solution polymerized styrene-butadiene rubber and emulsion polymerized styrene-butadiene rubber (e.g., one solution styrene- butadiene rubber and one emulsion styrene-butadiene rubber). In certain embodiments, the only styrene-butadiene rubber(s) present in the elastomer component (including for the at least one styrene-butadiene rubber having a silica- reactive or carbon black-reactive functional group) is (are) solution styrene-butadiene rubbers (i.e., no emulsion styrene-butadiene rubber is present).

[0136] The elastomer component comprises a hi-cis functionalized polybutadiene rubber (BR) and can also include an additional BR. The following characteristics can apply to either the hi-cis functionalized BR or an additional BR.

[0137] One or more BRs in the composition may have a cis bond content of at least 95% (e.g., 95%, 96%, 97%, 98%, 99%, or more), a Tg of less than -101 °C (e.g., - 102, -103, -104, -105, -106, -107, -108, -109, -110, -111, -112 °C or less), -101 or -110 °C (e.g., -102, -103, -104, -105, -106, -107, -108, -109, or -110 °C), or -103 or -109 °C. In certain such embodiments, the Tg of the polybutadiene rubber (ii) is -101 to -110 °C. The cis bond content refers to the cis 1,4- bond content. The cis 1,4-bond contents andP22296WO1A; BSP183WO vinyl bond contents referred to herein for polybutadiene rubber are determined by FTIR (Fourier Transform Infrared Spectroscopy) wherein a polymer sample is dissolved in CS2 and then subjected to FTIR. In certain embodiments, the polybutadiene rubber of (ii) has a cis 1,4-bond content of at least 98% (e.g., 98%, 99%, or more) or at least 99% (e.g., 99%, 99.5%, or more). Since the cis bond content of the polybutadiene rubber (ii) is high (i.e., at least 95%, as discussed above), the vinyl bond content will be low. In certain embodiments, the polybutadiene rubber of (ii) has a vinyl bond content of less than 4% (e.g., 3.9%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, etc.), such as less than 3% (e.g., 2.5%, 2%, 1.5%, 1%, 0.5%, etc.), or less than 2% (e.g., 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%,0.4%, etc.). In certain embodiments, any polybutadiene rubber used in the tire tread rubber compositions has a Tg of -105 °C or less (e.g., -105, -106, -107, -108, -109 °C or less) such as -105 to -110 °C. In certain embodiments, any polybutadiene rubber used in the tire tread rubber compositions contains less than 3% by weight (e.g., 3%, 2%, 1%, 0.5%, or less), less than 1% by weight (e.g., 1%, 0.5%, or less) or 0% by weight syndiotactic 1,2-polybutadiene. Generally, one or more than one polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, and a silica-reactive or carbon black-reactive functional group may be used for (ii). In certain embodiments, (ii) consists of only one polybutadiene rubber having a cis bond content of at least 95% (e.g., 95%, 96%, 97%, 98%, 99%, or more), a Tg of less than -101 °C, and a silica-reactive or carbon black-reactive functional group. In certain embodiments, the amount of any polybutadiene rubber having a high vinyl content (i.e., above about 70%) is limited (in the overall tread rubber composition) to less than 25 parts, such as less than 10 parts, or less than 5 parts or 0 parts.

[0138] In an embodiment, one or more BRs having a cis bond content of at least 95% (e.g., 95%, 96%, 97%, 98%, 99%, or more), a Tg of less than -101 °C (e.g., - 102, -103, -104, -105, -106, -107, -108, -109, -110, -111, -112 °C or less), such as, -101 or -110 °C (e.g., -102, -103, -104, -105, -106, -107, -108, -109, or -110 °C) are present in an amount of about 10 to about 65 parts (e.g., 15, 25, 35, 45, 49, 50, 51, 52, 53, 54, 55,P22296WO1A; BSP183WO 56, 57, 58, 59, 60, 61, 62, 63, 64 or 65 parts), such as about 20 to about 50 phr, or about 30 to about 40 phr.

[0139] In certain embodiments, the polybutadiene rubber having a cis bond content of at least 95%, and Tg of less than -101 °C has a Mw of about 150,000 to about 700,000 grams / mole (e.g., 250,000; 300,000; 450,000; 550,000; 650,000; or 700,000 grams / mole), Mw ranges falling within the foregoing ranges such as 200,000 to 600,000 grams / mole, 350,000 to 500,000 grams / mole, 400,000 to 450,000 grams / mole, and 500,000 to 700,000 grams / mole can also be utilized in certain embodiments. In certain embodiments, the polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C has a Mn of 180,000 to 300,000 grams / mole (e.g., 180,000; 200,000; 220,000; 240,000; 250,000; 260,000; 280,000; or 300,000 (g / mol), such as, a Mn of 200,000 to 280,000 grams / mole (e.g., 200,000; 210,000; 220,000; 230,000; 240,000; 250,000; 260,000; 270,000; or 280,000 grams / mole). Mn ranges falling within the foregoing ranges such as about 200,000 to about 250,000 grams / mole, 230,000 to 280,000 grams / mole, 180,000 to 280,000 grams / mole, and 200,000 to 280,000 grams / mole can also be utilized in certain embodiments. The foregoing Mw and Mn values for the polybutadiene refer to values measured by GPC using a polystyrene standard. As well, the foregoing Mw and Mn values for the polybutadiene refer to coupled Mw and coupled Mn rather than base polymer values.

[0140] In certain embodiments disclosed herein, the at least one polybutadiene rubber, can be an oil-extended rubber, incorporating oil in an amount as discussed further below. In other embodiments disclosed herein, the at least one polybutadiene rubber (ii), as described above, is a non oil-extended rubber (i.e., the BR is not extended with any oil).

[0141] In certain embodiments, the elastomer component may include up to about 100 phr (e.g., 65, 55, 45, 35, 25, 15, or 5 parts) of natural rubber, polyisoprene, or a combination thereof, which can be referred to as (iii). In certain embodiments, the amount of (iii) is about 20 to about 90 phr, and in other embodiments about 40 toP22296WO1A; BSP183WO about 80 phr parts. In certain embodiments, (iii) consists (only) of natural rubber. In other embodiments, (iii) consists (only) of polyisoprene. In yet other embodiments, as previously mentioned, no natural rubber or polyisoprene is present or used in the tire tread rubber composition. When natural rubber is present for (iii) of the elastomer component, it may include Hevea natural rubber, non-Hevea natural rubber (e.g., guayule natural rubber), or a combination thereof. When natural rubber is utilized in the tire tread rubber compositions, the natural rubber may have a Mw of about 1,000,000 to about 2,000,000 grams / mole (e.g., 1 million, 1.1 million, 1.2 million, 1.3 million, 1.4 million, 1.5 million, 1.6 million, 1.7 million, 1.8 million, 1.9 million, 2 million grams / mole); 1,250,000 to 2,000,000 grams / mole, or 1,500,000 to 2,000,000 grams / mole (as measured by GPC using a polystyrene standard). When natural rubber is utilized in the tire tread rubber compositions, the Tg of the natural rubber may vary. According to certain embodiments, when natural rubber is utilized it has a Tg of about - 65 to about -80 °C (e.g., - 65, -66, -67, -68, -69, -70, -71-, -72, -73, -74, -75, -76, -77, -78, -79, or -80 °C), a Tg of about -67 to about -77 °C (e.g., -67, -68, -69, -70, -71, -72, -73, -74, - 75, -76, or -77 °C). When polyisoprene is utilized in the tire tread rubber compositions, the Tg of the polyisoprene may vary. When polyisoprene is utilized it has a Tg of about -55 to about -75 °C (e.g., -55, -56, -57, -58, -59, -60, -61, -62, -63, - 64, -65, -66, -67, -68, -69, -70, -71, -72, -73, -74, or -75 °C), such as about -58 to about -74 °C (e.g., - 58, -59, - 60, -61, -62, -63, -64, -65, -66, -67, -68, -69, -70, -71, -72, -73, or -74 °C).

[0142] As used herein, the term “reinforcing” with respect to “reinforcing carbon black filler,” “reinforcing silica filler,” and “reinforcing filler” generally should be understood to encompass both fillers that are traditionally described as reinforcing as well as fillers that may traditionally be described as semi-reinforcing. Traditionally, theterm “reinforcing filler” is usedto refer to a particulate material that has a nitrogenabsorption specific surface area (N2SA) ofmore than about 100 m2 / g, and in certaininstances more than 100 m2 / g, more than about 125 m2 / g, more than 125 m2 / g, or even more than about 150 m2 / g or more than 150 m2 / g. Alternatively (or additionally), the traditional use of the term “reinforcing filler” can also be used to refer to aP22296WO1A; BSP183WO particulate material that has a particle size of about 10 nm to about 50 nm (including 10 nm to 50 nm). Traditionally, the term “semi-reinforcing filler” is used to refer to a filler that is intermediary in either particle size, surface area (N2SA), or both, to a non- reinforcing filler (as discussed below) and a reinforcing filler.

[0143] In embodiments disclosed herein, the term “reinforcing filler” is used to refer to a particulate material that has a nitrogen absorption specific surface area(N2SA) of about 20 m2 / g or greater,including 20 m2 / g or greater, more than about 50m2 / g, more than 50 m2 / g, more than about 100 m2 / g, or more than 100 m2 / g. In certain embodiments disclosed herein, the term “reinforcing filler” is used to refer to a particulate material that has a particle size of about 10 nm up to about 1000 nm, including 10 nm to 1000 nm, about 10 nm up to about 50 nm and 10 nm to 50 nm.

[0144] In an exemplary embodiment, the tire tread rubber compositions comprise at least one reinforcing silica filler in an amount of about 1 to about 100 phr (e.g., about 10 to 20, about 20 to 30, or about 30 to 45 phr), having a surface area of about 100 to about 300 m2 / g (e.g., 110, 120, 130, 140, 150, 160, 180, 200, 220, 240, 260, 280, or 300 m2 / g), such as, about 150 to about 300 m2 / g, or about 180 to about 250 m2 / g. In certain embodiments disclosed herein, the tire tread rubber compositions comprise at least one reinforcing silica filler in an amount of about 1 to about 30 phr (e.g., 3 to 25 phr, 5 to 20 phr, or 8 to 18 phr), having a surface area of values disclosed above. In embodiments, one or more than one reinforcing silica filler having a surface area as discussed above may be utilized; in those embodiments where more than one such reinforcing silica filler is utilized, the foregoing amounts refer to the total amount of all reinforcing silica fillers. In certain embodiments, only one reinforcing silica filler having a surface area as discussed above is utilized. In embodiments, the only reinforcing silica filler(s) used in the tire tread rubber composition have a surface area as discussed above; in such embodiments, the tire tread rubber composition can be understood as being free of (i.e., contains 0 phr of) reinforcing silica filler having a surface area outside the above-discussed ranges.P22296WO1A; BSP183WO

[0145] Non- limiting examples of reinforcing silica fillers suitable for use in certain embodiments include, but are not limited to, precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate, silica derived from rice husk ash, and the like. Other suitable reinforcing silicafillers for use in certain embodimentsinclude, but are not limited to, aluminum silicate,magnesium silicate (Mg2SiO4, MgSiO3etc.), magnesium calcium silicate (CaMgSiO4), calcium silicate (Ca2SiO4etc.), aluminum silicate (Al2SiO5, Al4.3SiO4.5H2O etc.),aluminum calcium silicate (Al2O3.CaO2SiO2, etc.), and thelike. Such reinforcing silicafillers are produced by a chemical reaction in water, from which they are precipitated as ultrafine, spherical particles, with primary particles strongly associated into aggregates, which in turn combine less strongly into agglomerates. The surface area, as measured by the BET method, is a measurement for characterizing the reinforcing character of different reinforcing silica fillers. In certain embodiments disclosed herein, the tire tread rubber composition comprises a reinforcing silica filler having a surface area (as measured by the BET method), as discussed infra. In certain embodiments disclosed herein, the tire tread rubber composition comprises reinforcing silica filler having a pH of about 5.5 to about 8, 5.5 to 8 (e.g., 5.5, 5.7, 5.9, 6.1, 6.3, 6.5, 6.7, 6.9, 7.1, 7.3, 7.5, 7.7, 7.9, or 8), about 6 to about 8, 6 to 8 (e.g., 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8, or 8), about 6 to about 7.5, 6 to 7.5, about 6.5 to about 8, 6.5 to 8, about 6.5 to about 7.5, 6.5 to 7.5, about 5.5 to about 6.8, or 5.5 to 6.8. Some of the commercially available reinforcing silica fillers which can be used in certain embodiments include, but are not limited to, Hi-Sil® EZ120G, Hi-Sil® EZ120G-D, Hi- Sil® 134G, Hi-Sil®EZ 160G, Hi-Sil®EZ 160G-D, Hi-Sil®190, Hi-Sil®190G-D, Hi-Sil® EZ 200G, Hi- Sil® EZ 200G-D, Hi-Sil® 210, Hi-Sil® 233, Hi-Sil® 243LD, Hi-Sil® 255CG-D, Hi-Sil® 315-D, Hi- Sil® 315G-D, Hi-Sil® HDP 320G and the like, produced by PPG Industries (Pittsburgh, Pa.) As well, a number of useful commercial grades of different reinforcing silica fillers are also available from Evonik Corporation (e.g., Ultrasil® 320 GR, Ultrasil® 5000 GR, Ultrasil® 5500 GR, Ultrasil® 7000 GR, Ultrasil® VN2 GR, Ultrasil® VN2, Ultrasil® VN3, Ultrasil® VN3 GR, Ultrasil®7000 GR, Ultrasil® 7005, Ultrasil® 7500 GR, Ultrasil® 7800 GR,P22296WO1A; BSP183WO Ultrasil® 9500 GR, Ultrasil® 9000 G, Ultrasil® 9100 GR), and Solvay (e.g., Zeosil® 1115MP, Zeosil® 1085GR, Zeosil® 1165MP, Zeosil® 1200MP, Zeosil® Premium, Zeosil® 195HR, Zeosil® 195GR, Zeosil® 185GR, Zeosil® 175GR, and Zeosil® 165 GR).

[0146] In certain embodiments disclosed herein, one or more than one silica coupling agent may also (optionally) be utilized. In embodiments, at least one silica coupling agent is utilized. Silica coupling agents are useful in preventing or reducing aggregation of the silica filler in rubber compositions. Aggregates of the silica filler particles are believed to increase the viscosity of a rubber composition, and, therefore, preventing this aggregation reduces the viscosity and improves the processability and blending of the rubber composition.

[0147] Generally, any conventional type of silica coupling agent can be used, such as those having a silane and a constituent component or moiety that can react with a polymer, particularly a vulcanizable polymer. The silica coupling agent acts as a connecting bridge between silica and the polymer. Suitable silica coupling agents for use in certain embodiments disclosed herein include those containing groups such as alkyl alkoxy, mercapto, blocked mercapto, sulfide-containing (e.g., monosulfide-based alkoxy-containing, disulfide-based alkoxy-containing, tetrasulfide-based alkoxy- containing), amino, vinyl, epoxy, and combinations thereof. In certain embodiments, the silica coupling agent can be added to the rubber composition in the form of a pre- treated silica; a pre-treated silica has been pre-surface treated with a silane prior to being added to the rubber composition. The use of a pre-treated silica can allow for two ingredients (i.e., silica and a silica coupling agent) to be added in one ingredient, which generally tends to make rubber compounding easier.

[0148] Alkyl alkoxysilanes have the general formula R10pSi(OR11)4-pwhereeach R11 isindependently a monovalent organic group, and p is an integer from 1 to 3, with the proviso that at least one R10is an alkyl group. In an embodiment, p is 1.Generally, each R10independently comprisesC1to C20aliphatic, C5to C20cycloaliphatic, or C6to C20aromatic; and each R11independently comprises C1to C6P22296WO1A; BSP183WO aliphatic. In certain exemplary embodiments, each R10independently comprises C6to C15aliphatic and in additional embodiments each R10independently comprises C8to C14aliphatic. Mercapto silanes have the general formula HS-R13-Si(R14)(R15)2whereR13 is adivalent organic group, R14is a halogen atom or an alkoxy group, each R15isindependently a halogen, an alkoxy group or a monovalent organic group. The halogen is chlorine, bromine, fluorine, or iodine. The alkoxy group may have 1-3 carbon atoms. Blocked mercapto silanes have the general formula B-S-R16-Si-X3 with an available silylgroup for reaction with silica in asilica-silane reaction and a blocking group B thatreplaces the mercapto hydrogen atom to block the reaction of the sulfur atom with the polymer. In the foregoing general formula, B is a block group which can be in the formof an unsaturated heteroatom or carbon bound directly to sulfurvia a single bond; R16is C1to C6linear or branched alkylidene and each X is independently selected from the group consisting of C1to C4alkyl or C1to C4alkoxy.

[0149] Non-limiting examples of alkyl alkoxysilanes suitable for use in certain embodiments include, but are not limited to, octyltriethoxysilane, octyltrimethoxysilane, trimethylethoxysilane, cyclohexyltriethoxysilane, isobutyltriethoxy-silane, ethyltrimethoxysilane, cyclohexyl-tributoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, propyltriethoxysilane, hexyltriethoxysilane, heptyltriethoxysilane, nonyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, tetradecyltriethoxysilane, octadecyltriethoxysilane, methyloctyldiethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, heptyltrimethoxysilane, nonyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, octadecyl-trimethoxysilane, methyloctyl dimethoxysilane, and mixtures thereof.

[0150] Non-limiting examples of bis(trialkoxysilylorgano)polysulfides suitable for use in certain embodiments include bis(trialkoxysilylorgano) disulfides and bis(trialkoxysilylorgano)tetrasulfides. Specific non-limiting examples ofP22296WO1A; BSP183WO bis(trialkoxysilylorgano)disulfides include, but are not limited to, 3,3'- bis(triethoxysilylpropyl) disulfide, 3,3'-bis(trimethoxysilylpropyl)disulfide, 3,3'- bis(tributoxysilylpropyl)disulfide, 3,3'- bis(tri-t-butoxysilylpropyl)disulfide, 3,3'- bis(trihexoxysilylpropyl)disulfide, 2,2'-bis(dimethylmethoxysilylethyl)disulfide, 3,3'- bis(diphenylcyclohexoxysilylpropyl)disulfide, 3,3'-bis(ethyl-di-sec- butoxysilylpropyl)disulfide, 3,3'-bis(propyldiethoxysilylpropyl)disulfide, 12,12'- bis(triisopropoxysilylpropyl)disulfide, 3,3'-bis(dimethoxyphenylsilyl-2- methylpropyl)disulfide, and mixtures thereof. Non-limiting examples of bis(trialkoxysilylorgano)tetrasulfide silica coupling agents suitable for use in certain embodiments include, but are not limited to, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl) tetrasufide, bis(3-trimethoxysilylpropyl)tetrasulfide, 3- trimethoxysilylpropyl-N,N- dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl- N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl- benzothiazole tetrasulfide, 3- triethoxysilylpropylbenzothiazole tetrasulfide, and mixtures thereof. Bis(3- triethoxysilylpropyl)tetrasulfide is sold commercially as Si69® by Evonik Degussa Corporation. In embodiments, the tire tread rubber composition includes a silica coupling agent in the form of a bis(trialkoxysilylorgano)polysulfides such as a bis(trialkoxysilylorgano) disulfide.

[0151] Non-limiting examples of mercapto silanes suitable for use in certain embodiments disclosed herein include, but are not limited to, 1- mercaptomethyltriethoxysilane, 2-mercaptoethyltriethoxysilane, 3- mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 2- mercaptoethyltripropoxysilane, 18-mercaptooctadecyldiethoxychlorosilane, and mixtures thereof.

[0152] Non-limiting examples of blocked mercapto silanes suitable for use in certain embodiments disclosed herein include, but are not limited to, those described in U.S. Pat. Nos.6,127,468; 6,204,339; 6,528,673; 6,635,700; 6,649,684; and 6,683,135, the disclosures of which are hereby incorporated by reference. Mixtures of variousP22296WO1A; BSP183WO blocked mercapto silanes can be used. A further example of a suitable blocked mercapto silane for use in certain exemplary embodiments is NXTTMsilane (3- octanoylthio-1-propyltriethoxysilane), commercially available from Momentive Performance Materials Inc. of Albany, NY.

[0153] Non-limiting examples of pre-treated silicas (i.e., silicas that have been pre-surface treated with a silane) suitable for use in certain embodiments disclosed herein include, but are not limited to, Ciptane® 255 LD and Ciptane® LP (PPG Industries) silicas that have been pre-treated with a mercaptosilane, and Coupsil® 8113 (Degussa) that is the product of the reaction between organosilane bis(triethoxysilylpropyl) polysulfide (Si69) and Ultrasil® VN3 silica. Coupsil 6508, Agilon 400™ silica from PPG Industries, Agilon 454® silica from PPG Industries, and 458® silica from PPG Industries. In those embodiments where the silica comprises a pre-treated silica, the pre-treated silica is used in an amount as previously disclosed for the silica filler.

[0154] When a silica coupling agent is utilized in an embodiment, the amount used may vary. In certain embodiments, the rubber compositions do not contain any silica coupling agent. In other embodiments, the silica coupling agent is present in an amount sufficient to provide a ratio of the total amount of silica coupling agent to silica filler of about 0.1:100 to about 1:5 (i.e., about 0.1 to about 20 parts by weight per 100 parts of silica), including 0.1:100 to 1:5, about 1:100 to about 1:10, 1:100 to 1:10, about 1:100 to about 1:20, 1:100 to 1:20, about 1:100 to about 1:25, and 1:100 to 1:25 as well as about 1:100 to about 0:100 and 1:100 to 0:100. In embodiments, the ratio of the total amount of silica coupling agent to silica filler falls within a ratio of 1:10 to 1:20 (i.e., 10 to 5 parts by weight per 100 parts of silica). In certain embodiments, the rubber composition comprises about 0.1 to about 15 phr silica coupling agent, including 0.1 to 15 phr (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 phr), about 0.1 to about 12 phr, 0.1 to 12 phr, about 0.1 to about 10 phr, 0.1 to 10 phr, about 0.1 to about 7 phr, 0.1 to 7 phr, about 0.1 to about 5 phr, 0.1 to 5 phr, about 0.1 to about 3 phr, 0.1 to 3 phr, about 1 to about 15 phr, 1 to 15 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 phr), about 1 to about 12 phr, 1 to 12 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8,P22296WO1A; BSP183WO 9, 10, 11, or 12 phr), about 1 to about 10 phr, 1 to 10 phr (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 phr), about 1 to about 7 phr, 1 to 7 phr, about 1 to about 5 phr, 1 to 5 phr, about 1 to about 3 phr, 1 to 3 phr, about 3 to about 15 phr, 3 to 15 phr, about 3 to about 12 phr, 3 to 12 phr, about 3 to about 10 phr, 3 to 10 phr, about 3 to about 7 phr, 3 to 7 phr, about 3 to about 5 phr, 3 to 5 phr, about 5 to about 15 phr, 5 to 15 phr, about 5 to about 12 phr, 5 to 12 phr, about 5 to about 10 phr, 5 to 10 phr, about 5 to about 7 phr, or 5 to 7 phr. In embodiments, the rubber composition comprises silica coupling agent in an amount of 8 to 12 phr or one of the foregoing ranges falling within this range.

[0155] Carbon Black Filler

[0156] In certain embodiments, the tire tread rubber composition contains about 25 to about 80 phr of carbon black, such as about 40 to about 70 phr, or about 45 phr to about 65 phr (such as, e.g., 30, 35, 40, 50, 60, or 65 phr). The foregoing amounts of carbon black filler should be understood to refer to reinforcing carbon black filler.

[0157] In those embodiments where carbon black filler is present, the particular type or types of carbon black utilized may vary. Generally, suitable carbon blacks for use as a reinforcing filler in the rubber composition of certain embodiments include any of the commonly available, commercially-produced carbon blacks, including those having a surface area of at least about 20 m2 / g (including at least 20 m2 / g) or at least about 35 m2 / g up to about 200 m2 / g or higher (including 35 m2 / g up to 200 m2 / g). Surface area values used herein for carbon blacks are determined by ASTM D-1765 using the cetyltrimethyl-ammonium bromide (CTAB) technique. Among the useful carbon blacks are furnace black, channel blacks, and lamp blacks. More specifically, examples of useful carbon blacks include super abrasion furnace (SAF) blacks, high abrasion furnace (HAF) blacks, fast extrusion furnace (FEF) blacks, fine furnace (FF) blacks, intermediate super abrasion furnace (ISAF) blacks, semi-reinforcing furnace (SRF) blacks, medium processing channel blacks, hard processing channelP22296WO1A; BSP183WO blacks and conducting channel blacks. Other carbon blacks which can be utilized include acetylene blacks. In certain embodiments, the rubber composition includes a mixture of two or more of the foregoing blacks. In an embodiment, if a carbon black filler is present it consists of only one type (or grade) of reinforcing carbon black. Typical suitable carbon blacks for use in certain embodiments are N-110, N-220, N-339, N-330, N-351, N-550, and N-660, as designated by ASTM D-1765-82a.

[0158] In one or more embodiments, carbon black can be sourced from a recycled material. Such recycled material can include reclaimed or recycled vulcanized rubber, whereby the vulcanized rubber is typically reclaimed from manufactured articles such as a pneumatic tire, an industrial conveyor belt, a power transmission belt, and a rubber hose. The recycled carbon black may be obtained by a pyrolysis process or other methods known for obtaining recycled carbon black. In an aspect, a recycled carbon black can be formed from incomplete combustion of recycled rubber feedstock or rubber articles. In another aspect, the recycled carbon black can be formed from the incomplete combustion of feedstock including oil resulting from the tire pyrolysis process. Any of the carbon blacks described herein and utilized in the inventive compounds can be in pelletized form or an unpelletized flocculent mass.

[0159] In certain embodiments, the tire tread rubber composition comprises a reinforcing filler other than carbon black or silica (i.e., an additional reinforcing filler). While one or more than one additional reinforcing filler may be utilized, their total amount may be limited to no more than 10 phr (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0 phr), or no more than 5 phr (e.g., 5, 4, 3, 2, 1, or 0 phr). In certain embodiments, the tire tread rubber composition contains no additional reinforcing filler (i.e., 0 phr); in other words, in such embodiments no reinforcing filler other than silica and optionally carbon black are present.

[0160] In those embodiments wherein an additional reinforcing filler is utilized, the additional reinforcing filler or fillers may vary. Non-limiting examples of suitable additional reinforcing fillers for use in the tire tread rubber compositions of certain embodiments include, but are not limited to, alumina, aluminum hydroxide, clayP22296WO1A; BSP183WO (reinforcing grades), magnesium hydroxide, boron nitride, aluminum nitride, titanium dioxide, reinforcing zinc oxide, and combinations thereof.

[0161] Non-Reinforcing Fillers

[0162] In certain embodiments, the tire tread rubber composition further comprises at least one non-reinforcing filler. In other embodiments, the tire tread rubber composition contains no non-reinforcing fillers (i.e., 0 phr). In embodiments wherein at least one non-reinforcing filler is utilized, the at least one non-reinforcing filler may be selected from clay (non-reinforcing grades), graphite, magnesium dioxide, aluminum oxide, starch, boron nitride (non-reinforcing grades), silicon nitride, aluminum nitride (non-reinforcing grades), calcium silicate, silicon carbide, ground rubber, and combinations thereof. The term “non- reinforcing filler” is used to refer to a particulate material that has a nitrogen absorption specificsurface area (N2SA) of lessthan about 20 m2 / g (including less than 20 m2 / g), and in certain embodiments less than about 10 m2 / g (including less than 10 m2 / g). The N2SA surface area of a particulate material can be determined according to various standard methods including ASTM D6556. In certain embodiments, the term “non-reinforcing filler” is alternatively or additionally used to refer to a particulate material that has a particle size of greater than about 1000 nm (including greater than 1000 nm). In those embodiments, wherein a non-reinforcing filler is present in the rubber composition, the total amount of non- reinforcing filler may vary but may be no more than 10 phr (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 phr), and in certain embodiments 1-10 phr, no more than 5 phr (e.g., 5, 4, 3, 2, or 1 phr), 1-5 phr, or no more than 1 phr.

[0163] In certain embodiments, the tire tread rubber composition comprises 0 to about 25 phr, about 1 phr to 20 phr, or about 7 phr to about 15 phr (e.g., 5, 15, 20, or 25 phr) of at least one hydrocarbon resin having a Tg of about 30 to about 50 °C (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42, 44, 45, 46, 48, or 50 °C). The tire tread rubber composition may comprise 0-25 phr (e.g., 2, 4, 8, 12, 16, 20, 24, or 25 phr) or other ranges discussed above, of at least one aromatic hydrocarbon resin having a Tg of about 30 to about 50 °C or 30-50 °C (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42,P22296WO1A; BSP183WO 44, 45, 46, 48, or 50 °C). Hydrocarbon resin Tg can be determined by DSC, according to the procedure discussed above for elastomer Tg measurements.

[0164] In an embodiment, the hydrocarbon resin comprises an aromatic resin optionally in combination with one or more additional resins selected from aliphatic, cycloaliphatic, and terpene resins; in those embodiments wherein one or more additional resins are present, the total amount of such additional resin(s) is, for example, no more than about 5 phr, less than 5 phr, less than 4 phr, less than 3 phr, less than 2 phr, or less than 1 phr (and in each instance no more than 10% by weight, or no more than 5% by weight of the overall amount of hydrocarbon resin). In other embodiments, the hydrocarbon resin consists of (only) an aromatic hydrocarbon resin. When an aromatic resin is used, one or more than one aromatic hydrocarbon resin may be utilized. In embodiments, the hydrocarbon resin includes less than about 5 phr of terpene resin, and may exclude any terpene resin (i.e., 0 phr of terpene resin is present in the tire tread rubber composition). As used herein, the term aromatic resin or aromatic hydrocarbon resin should be understood to include both aromatic homopolymer resins and aromatic copolymer resins. An aromatic copolymer resins refers to a hydrocarbon resin which comprises a combination of one or more aromatic monomers in combination with one or more other (non-aromatic) monomers, with the largest amount of any type of monomer being aromatic. An aromatic copolymer resin would include a hydrocarbon resin having 45% by weight aromatic monomers, in addition to 25% by weight cycloaliphatic monomers and 30% by weight aliphatic monomers as well as a hydrocarbon resin having 55% by weight aromatic monomers, in addition to 30% by weight cycloaliphatic monomers and 15% by weight aliphatic monomers. In certain embodiments, the hydrocarbon resin comprises one or more aromatic copolymer resins having a majority by weight of all monomers being aromatic (e.g., 51%, 55%, 60%, 65%, etc.). Non-limiting examples of aromatic resins suitable for use as the hydrocarbon resin in certain embodiments include coumarone-indene resins and alkyl- phenol resins as well as vinyl aromatic homopolymer or copolymer resins such as those including one or more of the following monomers: alpha-methylstyrene,P22296WO1A; BSP183WO styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyltoluene, para(tert-butyl)styrene, methoxystyrene, chlorostyrene, hydroxystyrene, vinylmesitylene, divinylbenzene, vinylnaphthalene or any vinyl aromatic monomer resulting from C9 fraction or C8-C10 fraction. Non-limiting examples of vinylaromatic copolymer resins include vinylaromatic / terpene copolymer resins (e.g., limonene / styrene copolymer resins), vinylaromatic / C5 fraction resins (e.g., C5 fraction / styrene copolymer resin), vinylaromatic / aliphatic copolymer resins (e.g., CPD / styrene copolymer resin, and DCPD / styrene copolymer resin). Non-limiting examples of alkyl-phenol resins include alkylphenol-acetylene resins such as p-tert- butylphenol-acetylene resins, alkylphenol-formaldehyde resins (such as those having a low degree of polymerization). Exemplary such aromatic resins are commercially available from various companies including Chemfax, Dow Chemical Company, Eastman Chemical Company, Idemitsu, Neville Chemical Company, Nippon, Polysat Inc., Resinall Corp., and Zeon under various trade names.

[0165] In certain embodiments, the hydrocarbon resin comprises an aromatic resin based upon one or more of the above-mentioned vinyl aromatic monomers (e.g., styrene, alpha-methylstyrene); in certain such embodiments at least about 80% by weight, at least 85% by weight, at least 90% by weight, at least 95% by weight, at least 98% by weight, at least 99% by weight, or even 100% by weight of the monomers in the aromatic resin are aromatic monomers. In certain embodiments, the hydrocarbon resin consists of an aromatic resin based upon one or more of the above- mentioned vinyl aromatic monomers (e.g., styrene, alpha-methylstyrene); in certain such embodiments at least 80% by weight, at least 85% by weight, at least 90% by weight, at least 95% by weight, at least 98% by weight, at least 99% by weight, or even 100% by weight of the monomers in the aromatic resin are aromatic monomers. In certain embodiments, the aromatic resin may include a hydrogenated form of one of the aromatic resins discussed above (i.e., a hydrogenated aromatic resin). In other embodiments, the aromatic resin excludes any hydrogenated aromatic resin; in other words, in such embodiments, the aromatic resin is not hydrogenated.P22296WO1A; BSP183WO

[0166] As mentioned above, in certain embodiments, the at least one hydrocarbon resin comprises (i) an aromatic resin in combination with (ii) an aliphatic resin. Non-limiting examples of aliphatic resins include C5 fraction homopolymer and copolymer resins. In an embodiment, the total amount of any aliphatic resin used in combination with the aromatic resin is no more than 5 phr, less than 5 phr, less than 4 phr, less than 3 phr, less than 2 phr, or less than 1 phr (and in each instance no more than 20% by weight, such as no more than 15% or no more than 10% by weight of the overall amount of hydrocarbon resin.

[0167] As mentioned above, in certain embodiments, the at least one hydrocarbon resin comprises (i) an aromatic resin in combination with (ii) a cycloaliphatic resin. Non-limiting examples of cycloaliphatic resins include cyclopentadiene (“CPD”) homopolymer or copolymer resins, dicyclopentadiene (“DCPD”) homopolymer or copolymer resins, and combinations thereof. The total amount of any cycloaliphatic resin used in combination with the aromatic resin is, e.g., may be no more than 5 phr, less than 5 phr, less than 4 phr, less than 3 phr, less than 2 phr, or less than 1 phr (and in each instance no more than 20% by weight, no more than 15%, or no more than 10% by weight of the overall amount of hydrocarbon resin.

[0168] In certain embodiments the at least one hydrocarbon resin comprises (i) an aromatic resin in combination with (ii) a terpene resin. Non-limiting examples of terpene resins include alpha-pinene resins, beta-pinene resins, limonene resins (e.g., L- limonene, D-limonene, dipentene which is a racemic mixture of L- and D-isomers), beta- phellandrene, delta-3-carene, delta-2-carene, and combinations thereof. The total amount of any terpene resin used in combination with the aromatic resin is, e.g., no more than 5 phr, less than 5 phr, less than 4 phr, less than 3 phr, less than 2 phr, or less than 1 phr (and in each instance no more than 20% by weight, such as no more than 15%, or no more than 10% by weight of the overall amount of hydrocarbon resin. As mentioned above, in embodiments, the hydrocarbon resin includes no terpene resin (i.e., 0 phr).P22296WO1A; BSP183WO

[0169] In certain embodiments, the hydrocarbon resin has a softening point of about 70 to about 100 °C or 70-100 °C (e.g., 70, 75, 80, 85, 90, 95, or 100 °C), about 75 to about 95 °C or 75-95 °C (e.g., 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or 95 °C), or about 80 to about 90 °C or 80-90 °C (e.g., 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 °C). Generally the softening point of a hydrocarbon resin will have a relationship to its Tg such that the Tg is lower than its softening point, and such that the lower the Tg the lower the softening point. As a non- limiting example, for two hydrocarbon resins having Tg’s of 70 and 100 °C, the resin with the Tg of 70 °C will have a lower softening point than the resin with the Tg of 100 °C.

[0170] In certain embodiments, the hydrocarbon resin meets at least one of the following: (a) a Mw of about 1000 to about 4000 grams / mole, 1000-4000 grams / mole (e.g., 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, or 4000 grams / mole), about 1000 to about 3000 grams / mole, 1000-3000 grams / mole (e.g., 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, or 3000 grams / mole), about 1000 to about 2500 grams / mole, 1000-2500 grams / mole (e.g., 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, or 2500 grams / mole), about 1000 to about 2000 grams / mole, 1000-2000 grams / mole (e.g., 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, or 2000 grams / mole), about 1100 to about 1800 grams / mole, or 1100-1800 grams / mole (e.g., 1100, 1200, 1300, 1400, 1500, 1600, 1700, or 1800 grams / mole); (b) a Mn of about 700 to about 1500 grams / mole, 700-1500 grams / mole (e.g., 700, 800, 900, 1000, 1100, 1200, 1300, 1400, or 1500 grams / mole), about 800 to about 1400 grams / mole, 800-1400 grams / mole (e.g., 800, 900, 1000, 1100, 1200, 1300, or 1400 grams / mole), about 800 to about 1300 grams / mole, 800-1300 grams / mole (e.g., 800, 900, 1000, 1100, 1200, or 1300 grams / mole), about 900 to about 1200 grams / mole, or 900-1200 grams / mole (e.g., 900, 950, 1000, 1050, 1100, 1150, or 1200 grams / mole); or (c) a polydispersity (Mw / Mn) of about 1 to about 2, 1-2 (e.g., 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7,P22296WO1A; BSP183WO 1.8, 1.9, or 2), about 1.1 to about 1.8, 1.1-1.8 (e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, or 1.8), about 1.1 to about 1.7, 1.1-1.7 (e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, or 1.7), about 1.2 to about 1.5, or 1.2 to 1.5 (e.g., 1.2, 1.3, 1.4, or 1.5). In certain embodiments, the hydrocarbon resin has a Mw according to one of the ranges provided above, in combination with a Mn according to one of the ranges provided above, further in combination with a Mw / Mn according to one of the ranges provided above; in certain such embodiments, the hydrocarbon resin is an aromatic resin.

[0171] In certain embodiments, the hydrocarbon resin comprises an aromatic resin (as discussed above) having an aromatic monomer content of at least about 40% by weight, at least 40% by weight (e.g., 40, 45, 50, 51, 55, 60% by weight, or more), about 40% to about 65% by weight, 40-65% by weight (e.g., 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 62, 64, or 65% by weight), at least about 45% by weight, at least 45% by weight (e.g., 45, 50, 51, 55, 60% by weight, or more), about 45% to about 65% by weight, 45-65% by weight (e.g., 45, 47, 49, 50, 51, 53, 55, 57, 59, 60, 61, 63, or 65% by weight), at least 51% by weight (e.g., 51, 55, 60, 65% by weight, or more), about 51% to about 65% (e.g., 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or 65%), 51-65%, about 51% to about 60%, 51-60% (e.g., 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%), about 51% to about 55%, or 51-55% (e.g, 51, 52, 53, 54, or 55%). The amounts of aromatic monomer content are weight percentages based upon the total weight of the respective hydrocarbon resin.

[0172] The tire tread rubber composition may comprise 0 to about 30 phr of liquid plasticizer (e.g., about 1 to about 20 phr, about 3 to about 10 phr, about 4 to about 8 phr, such as 2, 5, 7, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 phr), which may include at least one oil. In embodiments, the 1-20 phr of liquid plasticizer comprises at least one oil. In an embodiment, the 1-20 phr of liquid plasticizer consists of (only) at least one oil.

[0173] The term liquid plasticizer is used to refer to plasticizer ingredients which are liquid at room temperature (i.e., liquid at 25 °C and above) and to distinguish hydrocarbon resin plasticizers which will generally be solid at room temperature.P22296WO1A; BSP183WO Generally, liquid plasticizers will have a Tg below 0 °C, generally well below such as less than -30 °C, less than -40 °C, or less than -50 °C. In certain embodiments, the liquid plasticizer has a Tg of less than 0 °C to -100 °C, a Tg of -30 °C to -100 °C, or a Tg of -50 to -100 °C. Liquid plasticizers include both oils (e.g., petroleum oils as well as plant oils) and other non-oil liquid plasticizers including, but not limited to, ether plasticizers, ester plasticizers, phosphate plasticizers, and sulfonate plasticizers. Moreover, the term liquid plasticizer is meant to encompass both free liquid plasticizer (which is usually added during the compounding process) and extender oil (which is used to extend a rubber). Thus, by stating that the tire tread rubber composition comprises 1-20 phr of liquid plasticizer it should be understood that the total amount of any free liquid plasticizer (both oil plasticizer and non-oil liquid plasticizer) and any extender oil is 1- 20 phr.

[0174] In certain embodiments, the tire tread rubber composition contains only free liquid plasticizer in an amount of about 1-30 phr. In other embodiments, the tire tread rubber composition contains only extender oil in an amount of 1-30 phr. In yet other embodiments, the tire tread rubber composition includes both free liquid plasticizer and extender oil in a total amount of 1-30 phr.

[0175] In those embodiments wherein an oil-extended rubber is used, the amount of oil used to prepare the oil-extended rubber may vary. In those embodiments wherein an oil-extended rubber is used (e.g., an oil-extended SBR for (i)) and according to embodiments wherein the SBR (i) is oil-extended, the amount of oil used to prepare the oil-extended rubber may vary; in certain such embodiments, the amount of extender oil present in the oil-extended rubber (polymer) or SBR is about 1 to about 40 parts oil per 100 parts of rubber (e.g., 1, 5, 10, 15, 20, 25, 30, or 35 parts of oil per 100 parts or rubber), such as 10-20 parts oil per 100 parts or rubber, or 5-15 parts oil per 100 parts of rubber. As a non-limiting example, extender oil could be used in an amount of 40 parts oil per 100 parts rubber in an SBR for (i) which SBR is used in an amount of 40 parts (the 40 parts being the amount of polymer of the oil-extended SBR, as discussed previously) in the overall tread rubber composition and, thus, the amountP22296WO1A; BSP183WO of oil contributed by the oil-extended SBR to the tire tread rubber composition would be 16 phr. Oil-extension of rubbers (especially styrene- butadiene rubbers) can be beneficial to ease of processing or mixing when the SBR has a relatively high Mw and / or a relatively high Mooney viscosity.

[0176] In certain embodiments disclosed herein, the styrene-butadiene rubberas used in (i) is an oil-extendedstyrene-butadiene rubber having a polymer Mooneyviscosity ML1+4at 100 °C of at least 100. Bypolymer Mooney viscosity is meant theMooney viscosity of the rubber or polymer before oil- extension. When an oil-extended rubber is used in the elastomer component of the tire tread rubber composition disclosed herein, the amounts specified for (i) (and (ii)) should be understood to refer to the amounts of rubber only rather than the amounts of oil-extended rubber. As used herein, oil refers to both petroleum based oils (e.g., aromatic, naphthenic, and low PCA oils) as well as plant oils (such as can be harvested from vegetables, nuts, and seeds). Plant oils will generally comprise triglycerides and the term should be understood to include synthetic triglycerides as well as those actually sourced from a plant.

[0177] Various types of processing and extender oils may be utilized as the at least one liquid plasticizer, including, but not limited to aromatic, naphthenic, and low PCA oils (petroleum-sourced or plant-sourced). Suitable low PCA oils include those having a polycyclic aromatic content of less than 3 percent by weight as determined by the IP346 method. Procedures for the IP346 method may be found in Standard Methods for Analysis & Testing of Petroleum and Related Products and British Standard 2000 Parts, 2003, 62nd edition, published by the Institute of Petroleum, United Kingdom. Exemplary petroleum-sourced low PCA oils include mild extraction solvates (MES), treated distillate aromatic extracts (TDAE), TRAE, and heavy naphthenics. Exemplary MES oils are available commercially as CATENEX SNR from SHELL, PROREX 15, and FLEXON 683 from EXXONMOBIL, VIVATEC 200 from BP, PLAXOLENE MS from TOTAL FINA ELF, TUDALEN 4160 / 4225 from DAHLEKE, MES-H from REPSOL, MES from Z8, and OLIO MES S201 from AGIP. Exemplary TDAE oils are available as TYREX 20 from EXXONMOBIL, VIVATEC 500, VIVATEC 180, and ENERTHENEP22296WO1A; BSP183WO 1849 from BP, and EXTENSOIL 1996 from REPSOL. Exemplary heavy naphthenic oils are available as SHELLFLEX 794, ERGON BLACK OIL, ERGON H2000, CROSS C2000, CROSS C2400, and SAN JOAQUIN 2000L. Exemplary low PCA oils also include various plant-sourced oils such as can be harvested from vegetables, nuts, and seeds. Non- limiting examples include, but are not limited to, soy or soybean oil, sunflower oil (including high oleic sunflower oil), safflower oil, corn oil, linseed oil, cotton seed oil, rapeseed oil, cashew oil, sesame oil, camellia oil, jojoba oil, macadamia nut oil, coconut oil, and palm oil. The foregoing processing oils can be used as an extender oil, i.e., to prepare an oil-extended polymer or copolymer, or as a processing or free oil.

[0178] The liquid plasticizer may in certain embodiments include a non-oil plasticizer, non-limiting examples of which include ether plasticizers, ester plasticizers, phosphate plasticizers, and sulfonate plasticizers. In those embodiments where anon-oil plasticizer is present, o p t io n a l l y only a portion of the liquid plasticizer(e.g., less than 50%, no more than 40%, no more than 30%, no more than 20%, no more than 10%, or even no more than 5% is provided by the non-oil plasticizer). Exemplary ether plasticizers include polyethylene glycols and polypropylene glycols. Exemplary ester plasticizers include triesters and diesters in particular (which may be selected from the group consisting of di- and triesters of carboxylic acid, of phosphoric acid, or of sulphonic acid, and mixtures of these triesters). More specifically, exemplary carboxylic acid ester plasticizers include compounds selected from the group consisting of trimellitates, pyromellitates, phthalates, 1,2-cyclohexanedicarboxylates, adipates, azelates, sebacates, glyercol triesters, and mixtures of the foregoing. More specifically as to glycerol triesters, these may include more than 50% by weight, or more than 80% by weight of an unsaturated C18 fatty acid (e.g., oleic acid, linoleic acid, linolenic acid, and mixtures thereof). Other exemplary carboxylic acid ester plasticizers include stearic acid esters, ricinoleic acid esters, phthalic acid esters (e.g., di-2-ethylhexyl phthalate and diosodecyl phthalate), isophthalic acid esters, tetrahydrophthalic acid esters, adipic acid esters (e.g., di(2-ethylhexyl)adipate and diisooctyl adipate), malic acid esters, sebic acid esters (e.g., di(2-ethylhexyl)sebacate and diisooctyl sebacate), andP22296WO1A; BSP183WO fumaric acid esters. Exemplary phosphate plasticizers include those with a tri- hydrocarbyl phosphate and di-hydrocarbyl phosphate structures (where each hydrocarbyl is independently selected from alkyl of C1 to C12, C1 to C8, and aromatic of C6 to C12 (both substituted and un-substituted), when aromatic C6 is either substituted or un-substituted. More specifically, exemplary phosphate plasticizers include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, dioctyl phosphate, 2- ethylhexyl diphenyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, isodecyl diphenyl phosphate, tricresyl phosphate, tritolyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, and diphenyl mono-o-xenyl phosphate. Exemplary sulfonate plasticizers include sulfonic acid esters such as sulfone butylamide, toluenesulfonamide, N-ethyl- toluenesulfonamide, and N-cyclohexyl-p-toluencesulfonamide.

[0179] In certain embodiments, any oil utilized has a Tg of about -40 to about - 100 °C, -40 to -100 °C (e.g., -40, -45, -50, -55, -60, -65, -70, -75, -80, -85, -90, -95, or - 100°C), about -40 to about -90 °C, -40 to -90 °C (e.g., -40, -45, -50, -55, -60, -65, -70, - 75, -80, -85, or -90 °C), about -45 to about -85 °C, -45 to -85 °C (e.g., -45, -50, -55, -60, - 65, -70, -75, -80, or -85°C), about -50 to about -80 °C, or -50 to -80 °C (e.g., -50, -55, -60, -65, -70, -75, or -80 °C).

[0180] In certain embodiments, the tire tread rubber composition contains less than 5 phr (e.g., 4.5, 4, 3, 2, 1, or 0 phr) of MES or TDAE oil, or even no MES or TDAE oil (i.e., 0 phr). In certain embodiments, the tire tread rubber composition contains no petroleum oil (i.e., 0 phr) and instead any oil utilized is a plant oil. In certain embodiments, the tire tread rubber composition contains soybean oil in one of the above-mentioned amounts. In certain embodiments, the tire tread rubber composition contains no sunflower oil (i.e., 0 phr).

[0181] In certain embodiments the tire tread rubber composition includes one or more ester plasticizers. Suitable ester plasticizers are known to those of skill in the art and include, but are not limited to, phosphate esters, phthalate esters, adipate esters and oleate esters (i.e., derived from oleic acid). Taking into account that an esterP22296WO1A; BSP183WO is a chemical compound derived from an acid wherein at least one -OH is replaced with an -O- alkyl group, various alkyl groups may be used in suitable ester plasticizers for use in the tire tread rubber compositions, including generally linear or branched alkyl of C1 to C20 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20), or C6 to C12. Certain of the foregoing esters are based upon acids which have more than one -OH group and, thus, can accommodate one or more than one O-alkyl group (e.g., trialkyl phosphates, dialkyl phthalates, dialkyl adipates). Non-limiting examples of suitable ester plasticizers include trioctyl phosphate, dioctyl phthalate, dioctyl adipate, nonyl oleate, octyl oleate, and combinations thereof. The use of an ester plasticizer such as one or more of the foregoing may be beneficial to the snow or ice performance of a tire made from a tread rubber composition containing such ester plasticizer at least in part due to the relatively low Tg of ester plasticizers. In certain embodiments, the tire tread rubber composition includes one or more ester plasticizers having a Tg of -40 °C to -70 °C (e.g., -40, -45, -50, -55, -60, -65, or -70°C), or -50 °C to -65 °C (e.g., -50, -51, -52, -53, -54, -55, -56, -57, -58, -59, -60, -61, -62, -63, -64, or -65 °C ). In those embodiments wherein one or more ester plasticizers is utilized the amount utilized may vary. In certain embodiments, one or more ester plasticizers are utilized in a total amount of 1-12 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 phr), 1-10 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), 2-6 phr (e.g., 2, 3, 4, 5, or 6 phr) or 2-5 phr (e.g., 2, 3, 4, or 5 phr). In certain embodiments, one or more ester plasticizers is used in combination with oil in one of the foregoing amounts.

[0182] In an embodiment, the total amount of at least one hydrocarbon resin and at least one liquid plasticizer is 0 to about 50 phr (e.g., about 1 to about 40 phr, about 5 phr to about 35 phr, or about 10 phr to about 20 phr, such as, e.g., 18, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, or 46 phr). In certain embodiments, the total amount of hydrocarbon resin and liquid plasticizer is about 40 to about 50 phr (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 phr). In certain embodiments, the total amount of hydrocarbon resin and liquid plasticizer is no more than 49 phr (e.g., 49, 48, 47, 46,P22296WO1A; BSP183WO 45, 44, 43, 42, 41, 40, 39, 38, 37, or 36 phr, or a range from the foregoing such as 36-49 phr, etc.).

[0183] In certain embodiments, the amount of hydrocarbon resin is greater than the amount of liquid plasticizer. In certain such embodiments, the hydrocarbon resin and liquid plasticizer may be present in a weight ratio of at least 1.5:1, such as 1.5:1 to 3:1 (e.g., 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, or 3:1), or 1.6:1 to 2.8: (e.g., 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, or 2.8:1).

[0184] The tire tread rubber composition includes a cure package. Although the contents of the cure package may vary according to the embodiments, generally, the cure package includes at least one of: a vulcanizing agent; a vulcanizing accelerator; a vulcanizing activator (e.g., zinc oxide, stearic acid, and the like); a vulcanizing inhibitor; and an anti-scorching agent. In certain embodiments, the cure package includes at least one vulcanizing agent, at least one vulcanizing accelerator, at least one vulcanizing activator and optionally a vulcanizing inhibitor and / or an anti-scorching agent. Vulcanizing accelerators and vulcanizing activators act as catalysts for the vulcanization agent. Various vulcanizing inhibitors and anti-scorching agents are known in the art and can be selected by one skilled in the art based on the vulcanizate properties desired.

[0185] Examples of suitable types of vulcanizing agents for use in certain embodiments, include but are not limited to, sulfur or peroxide- based curing components. Thus, in certain such embodiments, the curative component includes a sulfur-based curative or a peroxide-based curative. In embodiments, the vulcanizing agent is a sulfur-based curative; in certain such embodiments the vulcanizing agent consists of (only) a sulfur-based curative. Examples of specific suitable sulfur vulcanizing agents include “rubbermaker’s” soluble sulfur; sulfur donating curing agents, such as an amine disulfide, polymeric polysulfide, or sulfur olefin adducts; and insoluble polymeric sulfur. The sulfur vulcanizing agent may be soluble sulfur or a mixture of soluble and insoluble polymeric sulfur. For a general disclosure of suitableP22296WO1A; BSP183WO vulcanizing agents and other components used in curing, e.g., vulcanizing inhibitor and anti-scorching agents, one can refer to Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd ed., Wiley Interscience, N.Y.1982, Vol.20, pp.365 to 468, particularly Vulcanization Agents and Auxiliary Materials, pp.390 to 402, or Vulcanization by A. Y. Coran, Encyclopedia of Polymer Science and Engineering, Second Edition (1989 John Wiley & Sons, Inc.), both of which are incorporated herein by reference. Vulcanizing agents can be used alone or in combination. Generally, the vulcanizing agents may be used in certain embodiments in an amount ranging from 0.1 to 10 phr (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), including from 1 to 7.5 phr (e.g., 1, 2, 3, 4, 5, 6, 7, or 7.5 phr), including from 1 to 5 phr (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 phr), and from 1 to 3.5 phr (e.g., 1, 1.5, 2, 2.5, 3, or 3.5 phr).

[0186] Vulcanizing accelerators are used to control the time and / or temperature required for vulcanization and to improve properties of the vulcanizate. Examples of suitable vulcanizing accelerators for use in certain embodiments disclosed herein include, but are not limited to, thiazole vulcanization accelerators, such as 2- mercaptobenzothiazole, 2,2'-dithiobis(benzothiazole) (MBTS), N-cyclohexyl-2- benzothiazole- sulfenamide (CBS), N-tert-butyl-2-benzothiazole-sulfenamide (TBBS), and the like; guanidine vulcanization accelerators, such as diphenyl guanidine (DPG) and the like; thiuram vulcanizing accelerators; carbamate vulcanizing accelerators; and the like. Generally, the amount of the vulcanization accelerator used ranges from 0.1 to 10 phr (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), such as 0.5 to 5 phr (e.g., 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 phr). In an embodiment, any vulcanization accelerator used in the tire tread rubber compositions excludes any thiurams such as thiuram monosulfides and thiuram polysulfides (examples of which include TMTM (tetramethyl thiuram monosulfide), TMTD (tetramethyl thiuram disulfide), DPTT (dipentamethylene thiuram tetrasulfide), TETD (tetraethyl thiuram disulfide), TiBTD (tetraisobutyl thiuram disulfide), and TBzTD (tetrabenzyl thiuram disulfide)); in other words, embodiments of the tire tread rubber compositions contain no thiuram accelerators (i.e., 0 phr).P22296WO1A; BSP183WO

[0187] Vulcanizing activators are additives used to support vulcanization. Generally vulcanizing activators include both an inorganic and organic component. Zinc oxide is the most widely used inorganic vulcanization activator. Various organic vulcanization activators are commonly used including stearic acid, palmitic acid, lauric acid, and zinc salts of each of the foregoing. Generally, in certain embodiments the amount of vulcanization activator used ranges from 0.1 to 6 phr (e.g., 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 phr), such as 0.5 to 4 phr (e.g., 0.5, 1, 1.5, 2, 2.5, 33.5, or 4 phr). In certain embodiments, one or more vulcanization activators are used which includes one or more thiourea compounds (used in one of the foregoing amounts), and optionally in combination with one or more of the foregoing vulcanization activators. Generally, a thiourea compound can be understood as a compound having thestructure (R1)(R2)NS(=C)N(R3)(R4) wherein each of R1, R2, R3, and R4areindependently selected from H, alkyl, aryl, and N-containing substituents (e.g., guanyl). Optionally, two of the foregoing structures can be bonded together through N (removing one of the R groups) in a dithiobiurea compound. In certain embodiments,one of R1or R2and one of R3or R4can be bonded togetherwith one or more methylene groups (-CH2-) therebetween. In certain embodiments, the thiourea hasone or two of R1, R2, R3and R4selected from one of the foregoing groups with the remaining R groups being hydrogen. Exemplary alkyl include C1-C6 linear, branched or cyclic groups such as methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, pentyl, hexyl, and cyclohexyl. Exemplary aryl groups include C6-C12 aromatic groups such as phenyl, tolyl, and naphthyl. Exemplary thiourea compounds include, but are not limited to, dihydrocarbylthioureas such as dialkylthioureas and diarylthioureas. Non-limiting examples of particular thiourea compounds include one or more of thiourea, N,N’- diphenylthiourea, trimethylthiourea, N,N’- diethylthiourea (DEU), N,N’- dimethylthiourea, N,N’-dibutylthiourea, ethylenethiourea, N,N’- diisopropylthiourea, N,N’-dicyclohexylthiourea, 1,3-di(o-tolyl)thiourea, 1,3-di(p-tolyl)thiourea, 1,1-diphenyl- 2-thiourea, 2,5-dithiobiurea, guanylthiourea, 1-(1-naphthyl)-2-thiourea, 1-phenyl- 2-P22296WO1A; BSP183WO thiourea, p-tolylthiourea, and o-tolylthiourea. In certain embodiments, the activator includes at least one thiourea compound selected from thiourea, N,N’-diethylthiourea, trimethylthiourea, N,N’-diphenylthiourea, and N-N’-dimethylthiourea.

[0188] Vulcanization inhibitors are used to control the vulcanization process and generally retard or inhibit vulcanization until the desired time and / or temperature is reached. Common vulcanization inhibitors include, but are not limited to, PVI (cyclohexylthiophthalmide) from Santogard. Generally, in certain embodiments the amount of vulcanization inhibitor is 0.1 to 3 phr (e.g., 0.1, 0.5, 1, 1.5, 2, 2.5, or 3 phr), such as 0.5 to 2 phr (e.g., 0.5, 1, 1.5, or 2 phr).

[0189] The particular steps involved in preparing the tire tread rubber compositions disclosed herein are generally comprising mixing the ingredients in at least one non-productive master-batch stage and a final productive mixing stage. In certain embodiments, the tire tread rubber composition is prepared by combining the ingredients for the rubber composition (as disclosed above) by methods known in the art, such as, for example, by kneading the ingredients together in a tangential-type, e.g., a Banbury mixer or on a milled roll. Such methods generally include at least one non- productive master-batch mixing stage and a final productive mixing stage. The term non-productive master-batch stage is known to those of skill in the art and generally understood to be a mixing stage (or stages) where no vulcanizing agents or vulcanization accelerators are added. The term final productive mixing stage is also known to those of skill in the art and generally understood to be the mixing stage where the vulcanizing agents and vulcanization accelerators are added into the rubber composition. In certain embodiments, the tire tread rubber composition is prepared by a process comprising more than one non-productive master-batch mixing stage.

[0190] In certain embodiments, the tire tread rubber composition is prepared by a process wherein the master-batch mixing stage includes at least one of tandem mixing or intermeshing mixing. Tandem mixing can be understood as including the use of a mixer with two mixing chambers with each chamber having a set of mixing rotors; generally, the two mixing chambers are stacked together with the upper mixer beingP22296WO1A; BSP183WO the primary mixer and the lower mixer accepting a batch from the upper or primary mixer. In certain embodiments, the primary mixer utilizes intermeshing rotors and in other embodiments the primary mixer utilizes tangential rotors. The lower mixer may utilize intermeshing rotors. Intermeshing mixing can be understood as including the use of a mixer with intermeshing rotors. Intermeshing rotors refers to a set of rotors where the major diameter of one rotor in a set interacts with the minor diameter of the opposing rotor in the set such that the rotors intermesh with each other. Intermeshing rotors must be driven at an even speed because of the interaction between the rotors. In contrast to intermeshing rotors, tangential rotors refers to a set of rotors where each rotor turns independently of the other in a cavity that may be referred to as a side. Generally, a mixer with tangential rotors will include a ram whereas a ram is not necessary in a mixer with intermeshing rotors.

[0191] Generally, the rubbers (or polymers) and at least one reinforcing filler (as well as any silane coupling agent and liquid plasticizer) will be added in a non- productive or master-batch mixing stage or stages. Generally, at least the vulcanizing agent component and the vulcanizing accelerator component of a cure package will be added in a final or productive mixing stage.

[0192] In certain embodiments, the tire tread rubber composition is prepared using a process wherein at least one non-productive master batch mixing stage is conducted at a temperature of about 130 °C to about 200 °C. In certain embodiments, the tire tread rubber composition is prepared using a final productive mixing stage conducted at a temperature below the vulcanization temperature in order to avoid unwanted pre-cure of the rubber composition. Therefore, the temperature of the productive or final mixing stage generally should not exceed about 120 °C and is typically about 40 °C to about 120 °C, or about 60 °C to about 110 °C and, especially, about 75 °C to about 100 °C. In certain embodiments, the tire tread rubber composition is prepared according to a process that includes at least one non- productive mixing stage and at least one productive mixing stage. The use of silica fillers may optionally necessitate a separate re-mill stage for separate addition of aP22296WO1A; BSP183WO portion or all of such filler. This stage often is performed at temperatures similar to, although often slightly lower than, those employed in the masterbatch stage, i.e., ramping from about 90°C to a drop temperature of about 150°C.

[0193] The use of the claimed amounts of the functionalized hi-cis polybutadiene in combination with other components of the tire tread rubber compositions can, in certain embodiments, result in an improvement in wear resistance as compared to a control rubber composition which uses a non- functionalized version of the polybutadiene having a cis bond content of at least 95% and a Tg of less than -101 °C. In certain embodiments, the tire tread rubber composition exhibits an improvement in wear of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 30%), at least about 10%, or at least about 15%, such as about 5 to about 35%, about 10 to about 31%, or about 15 to 22%. An improvement in wear can be measured by DIN abrasion values wherein a lower value (i.e., less material lost) indicates better wear.

[0194] In certain embodiments, the tire tread rubber composition exhibits other equivalent properties to the composition formed with the non-functionalized hi- cis polybutadiene. In other words, in exemplary embodiments, an improvement was realized with no detriment to other properties that may include one or more of rolling resistance, snow or ice traction, wet traction, cut / stiffness, heat generation, and tear. One or more of such properties may be predicted based on the evaluation of rubber compounds for E’ at 25°C, tan δ at 100°C, and 100°C hot aged E. Additional equivalent or desirable properties may include elongation at break (Eb), tensile at break (Tb) and TbxEb. While these properties may be measured by various methods, the values referred to herein are measured at the following temperatures and according to the following procedures. E’ and tan δ values can be measured with a dynamic mechanical thermal spectrometer (Eplexor® 500N from Gabo Qualimeter Testanlagen GmbH of Ahiden, Germany) generally following the guidelines of ASTM D5992-96 (2011) and under the following conditions: measurement mode: tensile test mode; measuring frequency: 52 Hz; applying 2% strain from 10 to 100 °C; collecting data approximatelyP22296WO1A; BSP183WO every 1 °C in order to provide measurements at temperatures of 25 °C, 60 °C, and 100 °C; sample shape: 4.75 mm wide x 29 mm long x 2.0 mm thick. Measurement is made upon a cured sample of rubber (cured for 33 minutes at 145°C).

[0195] In certain embodiments, the rubber composition has a value for tan δ at 60 °C of about 0.12 to about 0.26 (e.g., 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20 0.21, 0.22, 0.23, 0.24, or 0.25), 0.15 to 0.22, or 0.17 to 0.2. A tan δ at 60 °C within one of the foregoing ranges can be understood as being indicative of a tire (or more specifically, a tire tread) with moderate or low rolling resistance (a tire with low rolling resistance would generally be indicated by a tan δ at 60 °C of less than or equal to 0.2).

[0196] The wear performance of a tire tread rubber composition can be evaluated by various methods. However, the absolute wear values provided herein refer to DIN abrasion values that can be measured using standard methods including DIN ISO 53516. According to such method, the values represent the amount of material lost (in mm3) during the abrasion testing. When comparing two DIN abrasion values, a lower number indicates less material lost and corresponds to an improvement in wear. An improvement in wear can also be described as improved resistance to abrasion and is generally desirable in a tire tread since it leads to a tire having a longer lifespan (e.g., having a higher predicted mileage rating). In certain embodiments, the tire tread rubber composition has a DIN abrasion (according to DIN ISO 53516) of no more than 100 mm3(e.g., 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than no more than 95 mm3(e.g., 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than 90 mm3(e.g., 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than no more than 85 mm3(e.g., 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than 80 mm3(e.g., 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than 75 mm3(e.g., 75, 74, 73,P22296WO1A; BSP183WO 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), no more than 70 mm3(e.g., 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60 mm3or less), or 100 to 60 mm3(including ranges within the foregoing), 95 to 60 mm3(including ranges within the foregoing), 90 to 60 mm3(including ranges within the foregoing), 85 to 60 mm3(including ranges within the foregoing), 80 to 60 mm3(including ranges within the foregoing), 75 to 60 mm3(including ranges within the foregoing), 70 to 60 mm3(including ranges within the foregoing), 100 to 70 mm3(including ranges within the foregoing), 95 to 70 mm3(including ranges within the foregoing), 90 to 70 mm3(including ranges within the foregoing), 85 to 70 mm3(including ranges within the foregoing), 80 to 70 mm3(including ranges within the foregoing), 100 to 80 mm3(including ranges within the foregoing), 95 to 80 mm3(including ranges within the foregoing), or 90 to 80 mm3(including ranges within the foregoing).

[0197] The tire tread rubber compositions can be considered to be particularly useful in terms of providing a tire tread improved wear performance. By stating that the wear performance is improved is meant that the wear performance (as measured by ISO 23337:2016)) is at least 101% of a control. As non-limiting examples, if a sample exhibited an abrasion loss of 0.0055 mg and its control exhibited an abrasion loss of 0.0050, the sample could be described as having a wear performance that is 95% of its control and if a sample exhibited an abrasion loss of 0.0054 mg and its control exhibited an abrasion loss of 0.0060 mg, the sample could be described as having a wear performance that is improved by 10% as compared to its control. According to the foregoing descriptions, a wear performance that is 100% of its control should be understood as having a wear performance that is equal to its control and the comparisons to control are calculated by dividing the control value by the sample value and multiplying by 100%.

[0198] In certain embodiments, the rubber composition has a room temperature Eb of at least 400% (e.g., 420%, 440%, 465%, 485%, 495%, 500%, 505%, 510%, 515%, 520%, 525%, 530%, 535%, 540%, 545%, 550%, 555%, 560%, 565%, 570%, 575%, 580%, 585%, 590%, 595%, 600%, 605%, 610%, 615%, 620%, 625%, 630%, 635%,P22296WO1A; BSP183WO 640%, 645%, 650%, or more) or within the range of 440 to 650% or a sub-range within that range, such as at least 470% (e.g., 475%, 480%, 500%, 515%, 520%, 525%, 530%, 535%, 540%, 545%, 550%, 555%, 560%, 565%, 570%, 575%, 580%, 585%, 590%, 595%, 600%, 605%, 610%, 615%, 620%, 625%, 630%, 635%, 640%, 645%, 650%, or more) or within the range of 500 to 650% or a sub-range within that range. The foregoing room temperature Eb values refer to measurements made at 23 ° C. Eb can be measured following the guidelines, but not restricted to, the standard procedure described in ASTM D-412, with dumbbell-shaped samples having a cross-section dimension of 4 mm in width and 1.9 mm in thickness at the center. During measurement, specimens may be strained at a constant rate (20% per second) and the resulting force recorded as a function of extension (strain).

[0199] In certain embodiments, the rubber composition has a hot Eb of at least about 375%, (e.g., 375%, 400%, 415%, 430%, 445%, 460%, 475%, 490%, 505%, 520%, 535%, 550%, 565%, 580%, 595% or more) or within a range of 375-650% or a sub-range within that range, such as at least about 400% (e.g., 400%, 450%, 550%, 575%, 590%, 600%, 610%, 620%, 630%, 640%, 650%, or more) or within a range of about 400 to about 600% or a sub-range within that range, such as about 425% to about 550%. The foregoing hot Eb values refer to measurements made at 100 °C. Eb can be measured following the guidelines, but not restricted to, the standard procedure described in ASTM D-412, with dumbbell-shaped samples having a cross-section dimension of 4 mm in width and 1.9 mm in thickness at the center. During measurement, specimens may be strained at a constant rate (20% per second) and the resulting force recorded as a function of extension (strain). Generally, a hot Eb value for a given tread rubber composition will be lower (i.e., less than) the room temperature Eb for that tread rubber composition.

[0200] Generally, the process of making the functionalized hi-cis BR described herein can be considered to be a solution polymerization process. In this type of polymerization process, the polymerization reaction takes place in organic solvent- based solution, such as hexane. Here, that organic solvent-based solution initiallyP22296WO1A; BSP183WO contains a quantity of conjugated diene monomer and a specified catalyst system. Generally, the organic solvent-based solution comprises about 15-90% by weight (wt%) organic solvent based on the total weight of the monomer, organic solvent, and polybutadiene in the solution. The organic solvent comprises the predominant component of the solution, e.g., greater than 50-90 wt% organic solvent, or 70 wt% to 90 wt% organic solvent based on the total weight of the monomer, organic solvent, and polybutadiene. The solution polymerization processes disclosed herein can be contrasted with gas-type or bulk-type polymerizations, where polymerization is carried out in the absence of any organic solvent or where there is less than 20 wt% organic solvent present based on the total weight of the monomer, organic solvent, and polybutadiene.

[0201] Suitable organic solvents for use in solution polymerization processes according to an embodiment described herein are those solvents that are inert to the polymerization reaction such that the solvent is not a reactant in the polymerization reaction. Suitable organic solvents include aromatic hydrocarbons, aliphatic hydrocarbons, a nd cycloaliphatic hydrocarbons. Examples of suitable aromatic hydrocarbon solvents include, but are not limited to benzene, toluene, ethylbenzene, diethylbenzene, naphthalenes, mesitylene, xylenes, and the like. Examples of suitable aliphatic hydrocarbon solvents include, but are not limited to, n- pentane, n-hexane, n- heptane, n-octane, n-nonane, n-decane, isopentane, hexanes, isohexanes, isopentanes, isooctanes, 2,2-dimethylbutane, petroleum ether, kerosene, petroleum spirits, and the like. Non-limiting examples of suitable cycloaliphatic hydrocarbon solvents include cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, and the like. Mixtures of the foregoing aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, and cycloaliphatic hydrocarbon solvents can also be used. In certain embodiments, the organic solvent includes an aliphatic hydrocarbon solvent, a cycloaliphatic hydrocarbon solvent, or mixtures thereof.

[0202] Solution polymerization is optionally conducted under anaerobic conditions under a blanket of inert gas, such as nitrogen, argon, or helium. TheP22296WO1A; BSP183WO polymerization temperature may vary widely, ranging from -50 °C to 150 °C, such as 50 °C to 120 °C. The polymerization pressure may also vary widely, ranging from 1 atmosphere (atm) to 30 atm, such as 1 atm to 10 atm (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 atm).

[0203] A solution polymerization process may be conducted as a continuous, a semi-continuous, or a batch process. In a semi- continuous process, the monomer is intermittingly charged to replace the monomer that has already polymerized. The polymerization of 1,3-butadiene monomer into a high-cis polybutadiene in accordance with the processes described herein occurs when the monomer and the lanthanide- based catalyst system are all present in the organic solvent-based solution. The order of addition of the monomer and catalyst to the organic solvent does not matter.

[0204] Generally, the polymerization process can be stopped by adding any suitable terminating agent. Non-limiting examples of suitable terminating agents include protic compounds, such as alcohols, carboxylic acids, inorganic acids, water, and mixtures thereof. Other suitable terminating agents are known to those skilled in the art. Furthermore, once the polymerization has been stopped, the resulting high-cis polydiene can be recovered (or isolated) from the solution using conventional methods, e.g., steam desolventization or steam distillation, coagulation with an alcohol, filtration, purification, drying, etc., known to those skilled in the art. In embodiments, the high-cis polybutadiene polymer is isolated by the use of steam distillation.

[0205] It is specifically contemplated that the tire tread rubber composition, as disclosed herein, will be utilized in a tire tread, and in particular for passenger tire (PSR) or alternatively a TBR (truck and bus, radial tire tread, such as a TBR steer tire tread). Thus, also disclosed herein is a tire tread comprising the tire tread rubber composition. As well, such a tire tread can be utilized in a tire (along with other components). Thus, also disclosed herein is a tire having a tread comprising the tire tread rubber composition according embodiments, as discussed herein.P22296WO1A; BSP183WO

[0206] A TBR tire is one that has a load index (LI) corresponding to the min and max values in Table 1 below and is distinguished from a passenger tire (PSR) as shown below: Table 1 European Tire and Rim Technical min LI max LI Organization (ETRTO) 2 6re; in another embodiment, the tire is a TBR tire that has an LI of about 123 to about 165, such as about 130 to about 160, or about 135 to about 155. Load index is a numerical code known and commonly used by those of skill in the art that indicates the maximum load that a tire can carry at the speed indicated by its speed index in the conditions of use specified by the manufacturer. In an embodiment, a TBR tire is one that is designed to support at least a vehicle weighing at least 5 tons. The TBR tread pattern may also be a continuous rib pattern. The TBR tread may have an initial (prior to installation on a wheel) groove depth of 7 to 27mm. The TBR tread pattern may consist of a combination of continuous ribs, lugs, and tread blocks. TBR tire sizes may be selected from the group consisting of: 9R17.5, 295 / 75R22.5, 11R24.5, 11R22.5, 255 / 70R22.5, 285 / 70R19.5, 285 / 75R24.5, 445 / 50R22.5, 315 / 80R22.5, 295 / 80R22.5, 385 / 65R22.5, 225 / 70R19.5, 295 / 60R22.5, 245 / 70R19.5, 245 / 70R17.5, 305 / 70R22.5, 275 / 70R22.5, 12.00R24, 12R22.5, 9R22.5, 10R22.5, 11.00R22, 10.00R20, 275 / 80R22.5, 215 / 75R17.5, 235 / 75R17.5, 365 / 70R22.5, 445 / 65R22.5, 425 / 65R22.5, 12R24.5, 265 / 70R19.5, 305 / 75R24.5, 265 / 75R22.5, 245 / 75R22.5, 9.00R20. In an embodiment, the TBR tire size may be selected from the group consisting of: 295 / 75R22.5, 11R24.5, 11R22.5, or 285 / 75R24.5.

[0208] The term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phraseP22296WO1A; BSP183WO “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form.

[0209] The term “about” should be considered to mean within 2% of the stated value. All numbers and ranges disclosed herein should be considered to include the modifier “about” and also not including the modifier “about.”

[0210] As used herein, the term “exemplary” is intended to mean serving as an illustration or example of something, and is not intended to indicate a preference.

[0211] As used herein the term “natural rubber” means naturally occurring rubber such as can be harvested from sources such as Hevea rubber trees and non- Hevea sources (e.g., guayule shrubs and dandelions such as TKS). In other words, the term “natural rubber” should be construed so as to exclude synthetic polyisoprene.

[0212] As used herein, the term “phr” means parts per one hundred parts rubber. The 100 parts rubber refers to 100 parts of the at least one conjugated diene monomer-containing rubber.

[0213] As used herein the term “polyisoprene” means synthetic polyisoprene. In other words, the term is used to indicate a polymer that is manufactured from isoprene monomers, and should not be construed as including naturally occurring rubber (e.g., Hevea natural rubber, guayule-sourced natural rubber, or dandelion- sourced natural rubber). However, the term polyisoprene should be construed as including polyisoprenes manufactured from natural sources of isoprene monomer.

[0214] Unless otherwise indicated herein, the term “Mooney viscosity” refers to theMooney viscosity, ML1+4.Mooney viscosity is measured prior to vulcanization or curing.

[0215] As used herein, the term "natural rubber" means naturally occurring rubber such as can be harvested from sources such as Hevea rubber trees and non-P22296WO1A; BSP183WO Hevea sources (e.g., guayule shrubs and dandelions such as TKS). In other words, the term "natural rubber" should be construed so as to exclude synthetic polyisoprene.

[0216] As used herein, the term “phr” means parts per one hundred parts rubber. The one hundred parts rubber is also referred to herein as 100 parts of an elastomer component.

[0217] As used herein, the term “tread,” refers to both the portion of a tire that comes into contact with the road under normal inflation and load as well as any subtread.

[0218] EXAMPLES

[0219] Starting materials

[0220] Hexanes (mixture of isomers) and 1,3-butadiene (BD) were obtained from Firestone Polymer Company (FSPC). A pre-formed active neodymium catalyst (COMCAT Nd-FC20) was obtained from COMAR. Diisobutylaluminum hydride (DIBAH or DIBAL or DIBAL-H) and pyrazinecarbonitrile were obtained from SIGMA-ALDRICH.

[0221] The microstructure content of the polymers was determined by 400 MHz NMR using CDCl3 as the solvent. Polymer Mooney viscosities were determined using a Monsanto Mooney viscometer. The ML(1+4) values were measured on a large rotor at 100 ºC for 4 mins with a 1 min warm up time.

[0222] The number average (Mn) molecular weight, weight average (Mw) molecular weight, and polydispersity (PDI) (Mw / Mn) were determined by gel permeation chromatography (GPC) using a TOSOH Ecosec HLC-8320 GPC system and TOSOH TSKgel GMHxl-BS columns with THF as a solvent. The system was calibrated using polystyrene (PS) standards and referenced to PS standards. Molecular weights were corrected to high-cis BR values by re-calculating the GPC polystyrene calibration curve using the Mark-Houwink relationship (K1M1^(a1+1) = K2M2^(a2+1)) where K = 0.0001249 and a = 0.72 for polystyrene and K = 0.000166 and a = 0.79 for high-cis BR.

[0223] Total nitrogen analysis was performed on re-coagulated samples using a Mitsubishi Chemical Analytech NSX-2100 Element Analyzer System. The number of nitrogen atoms per average polymer chain is determined by taking the nitrogen ppmP22296WO1A; BSP183WO level and multiplying it by ratio of the number average molecular weight (Mn) to the molecular weight of a nitrogen atom then dividing by 1,000,000 (e.g. number of nitrogen atoms per average polymer chain = [(Nitrogen ppm) * (Polymer Mn / 14.01)] / 1,000,000).

[0224] The number of pyrazinecarbonitrile per avg polymer chain is calculated by dividing the number of nitrogen atoms per avg polymer chain by the number of nitrogen atoms in the functional group attached to the polymer chain end. In the case of pyrazinecarbonitrile, there are three nitrogen atoms so the number of pyrazinecarbonitrile per average polymer chain is calculated by dividing the number of nitrogen atoms per avg polymer chain by three. This calculation represents a modification efficiency estimate (i.e., the average percent of polymer chains that contain a functional group) if all nitrogen atoms are retained. It is possible that some nitrogen atoms are hydrolyzed off the polymer chain and thus the calculation in under counting the number of chain ends with a functional group. This calculation does not specifically account for coupling; coupling may occur through two or more polymer chain ends reacting with a single pyrazinecarbonitrile or through two or more polymer chains functionalized with pyrzainecarbonitrile reacting with each other or through coordinating with a metal present in the polymerization (e.g. aluminum). The number average molecular weight (Mn) used in this calculation is the Mn corrected to a high-cis BR value using the Mark-Houwink relationship described above.

[0225] Example 1: Synthesis of High Cis BR

[0226] To a 5-gallon nitrogen-purged reactor equipped with turbine agitator blades 2.85 kg of hexane and 8.51 kg of 18.8 wt% 1,3-butadiene in hexane was added. Next, 8.84 mL 1.0 M diisobutylaluminum hydride (DIBAL, 3.3 Al:Nd) in hexane was added to the reactor, followed by the addition of 6.02 mL of 0.452 M Nd-COMCAT (0.170 mmol phgm). The reactor jacket temperature was then set to 50 °C.

[0227] The polymerization had an exotherm of 180 °C after 25 minutes of polymerization. After 60 minutes of polymerization time, the resulting polymer cement was then transferred into 2 buckets, each containing approximately 6 L of isopropanolP22296WO1A; BSP183WO and 11 g of butylated hydroxytoluene (BHT). The coagulated polymer sample was dried by a drum-drier at 120 °C. Polymer characterization data of the BR is summarized in Table 2.

[0228] Example 2: Synthesis of pyrazinecarbonitrile Functional high-cis BR

[0229] To a 5-gallon nitrogen-purged reactor equipped with turbine agitator blades 2.85 kg of hexane and 8.51 kg of 18.8 wt% 1,3-butadiene in hexane were added. Next, 8.84 mL 1.0 M diisobutylaluminum hydride (DIBAL, 3.3 Al:Nd) in hexane was added to the reactor, followed by the addition of 6.02 mL of 0.452 M Nd-COMCAT (0.170 mmol phgm). The reactor jacket temperature was then set to 50 °C. The polymerization had an exotherm of 181 °C after 25 minutes of polymerization.

[0230] After 50 minutes of polymerization time, 4.87 mL pyrazinecarbonitrile, neat 11.170 M, 20:1 to Nd), diluted with approximately 30 mL of hexane, was added to the reactor.

[0231] After an additional 40 minutes (90 minutes total), the resulting polymer cement was then transferred into 2 buckets, each containing approximately 6 L of isopropanol and 11 g of butylated hydroxytoluene (BHT).

[0232] The coagulated polymer sample was dried by a drum-drier at 120 °C. Polymer characterization data of the BR of Examples 1 and 2 is summarized in Table 2.

[0233] Table 2. Polymer Characterization of high-cis BR Samples Example 1 (Comparative) 2 (Inventive)P22296WO1A; BSP183WO Mw (PS Std) (g / mol) 515,754 570,724 %)

[0235] Rubber composition samples were produced using natural rubber (NR), a styrene-butadiene rubber (SBR), and a polybutadiene rubber (BR). The SBR utilized is a commercial grade SBR functionalized for interaction with carbon black and has a styrene content of ~35% and a vinyl content of ~20% (based on butadiene portion. The low-cis BR utilized in comparative examples 3 and 7 is a commercial grade BR functionalized for interaction with carbon black (referred to herein as “CB-functionalized”) and has a vinyl content of ~15%. The high-cis BR utilized in comparative examples 4 and 8 is a commercial grade BR that is not functionalized for interaction with any filler and has a 1,4-cis content of ~96%.

[0236] The rubber compositions were produced from mixing in a 6-lb Kobelco internal mixer in three separate stages: premass, masterbatch, and final. The premass stages includes the following components: natural rubber and a portion of the carbon black (CB). The premass composition is a 1:20 ratio of carbon black to natural rubber.

[0237] The masterbatch stage includes the following components: styrene- butadiene rubber (SBR), butadiene rubber (BR), the remaining carbon black (CB), silica (SiO2), oil, stearic acid, wax, 1,3-dimethylbutyl-N'phenyl-p-phenylenediamine (6PPD), aP22296WO1A; BSP183WO C5 / C9 resin, silane, a portion of the ZnO, and a portion of the diphenylguanidine (DPG) for the silica-containing compound.

[0238] The Final stage includes the remaining ZnO, sulfur, cyclohexyl benzothiazole sulfenamide (CBS) and diphenylguanidine (DPG). Ratios of materials are reported in parts per hundred rubber (phr) in Table 3.

[0239] The premass stage was mixed at 60 rpm rpm until the sample reached 127 ºC. The masterbatch stage was mixed at 60 rpm for 3.5 minutes or until the sample reached 160 ºC, whichever occurred first. The final stage was mixed at 40 rpm for 2.5 minutes or until the sample reached 104 ºC, whichever occurred first. Samples were cured at 145 °C for 33 minutes. Selected formulation details are listed in Tables 2 and 3.

[0240] Table 3. Compound Formulation in All CB System 6 Example 3 (Comparative) 4 (Comparative) 5 (Comparative) (Inventive)

[0241] Table 4. Compound Formulation in Mixed CB / Si System 7 8 10 Exam le 9 (Com arative)P22296WO1A; BSP183WO (Non-Fxn Base Polym)p p , modulus at 300% strain M300, stress at break Eb, and maximum strain Tb were determined following the guidelines in the standard procedure described in ASTM D412, using dumbbell specimens. Specimens were strained at a constant rate and the resulting force was recorded as a function of extension (strain). Force readings were expressed as engineering stresses by reference to the original cross-sectional area of the test piece. The specimens were tested at 23 °C. The same tensile mechanical properties were also tested at 100 °C. Maximum stress and maximum strain percentage were also measured at both temperatures.

[0243] The viscoelastic properties loss tangent tan δ (100 °C), loss tangent tan δ (60 °C), and storage modulus E’ at 25 °C, described herein, were measured by a temperature sweep test conducted with a GABO Eplexor at 2% strain with varied temperature.

[0244] The abradability properties, were measured by an A&D Lambourn machine to determine the wear energy versus wear rate trends of the variousP22296WO1A; BSP183WO compounds. In all cases the inventive examples showed significant improvement over the comparative examples.

[0245] When the pyrazinecarbonitrile Functional high-cis BR (Example 2) was used in a formulation containing only CB filler (Example 6), it was found to have lower abrasion than a CB-functional low-cis BR (control Example 3), a commercial non- functional high-cis BR (neodymium catalyzed with 96% cis) (control Example 4), and a laboratory synthesized non-functional high-cis BR (control Example 5) while maintaining similar tensile properties (Table 5). Example 6 had 15% to 27% lower abradability than the control compounds (Table.4).

[0246] Lower abradability indicates a higher resistance to abrasion (or wear) for on-tire tread properties. Use of pyrazinecarbonitrile Functional high-cis BR in a pure CB formula (Example 6) did afford a slightly higher loss tangent tan δ (60 °C) compared to the CB-functional low-cis BR (control Example 3) but an equivalent tangent tan δ (60 °C) compared to a commercial non-functional high-cis BR (control Example 4), and a laboratory synthesized non-functional high-cis BR (control Example 5) (Table 5).

[0247] Table 5. Selected Compound Properties in All CB System Example 3 (Comparative) 4 (Comparative) 5 (Comparative) 6 (Inventive)P22296WO1A; BSP183WO E’ @ 25C index to 100 106

[0248] When the pyrazinecarbonitrile Functional high-cis BR (Example 2) was used in a formulation containing a mixture of CB and silica fillers (Example 10), it was found to have lower abrasion than a CB-functional low-cis BR (control Example 7), a commercial non-functional high-cis BR (control Example 8), and a laboratory synthesized non-functional high-cis BR (control Example 9) while maintaining similar tensileP22296WO1A; BSP183WO properties (Table 6). Example 10 had 13% to 40% lower abradability than the control compounds (Table 6).

[0249] Use of pyrazinecarbonitrile Functional high-cis BR in a mixed CB / silica formula (Example 10) did afford a slightly higher loss tangent tan δ (60 °C) compared to the CB-functional low-cis BR (control Example 7) but an at least equivalent tangent tan δ (60 °C) compared to a commercial non-functional high-cis BR (control Example 8) and a laboratory synthesized non-functional high-cis BR (control Example 9) (Table 6).

[0250] Table 6. Selected Compound Properties in Mixed CB / Si System 8 Example 7 (Comparative) 9 (Comparative) 10 (Inventive) (Comparative)P22296WO1A; BSP183WO Tand @ 100 104 109 109 100C

[0251] Hot Eb and hot aged elongation at break EB data was determined and is provided in the tables below. The hot Eb samples were tested at 100°C. The hot aged examples were aged 1 Day at 100°C and tested at 100°C.

[0252] Table 7: Hot Eb and Hot Aged Eb Data Example 3 (Comparative) 4 (Comparative) 5 (Comparative) 6 (Inventive) BTable 8: Hot Eb and Hot Aged Eb Data Example 7 (Comparative) 8 (Comparative) 9 (Comparative) 10 (Inventive)

[0253] The pyrazinecarbonitrile high cis BR shows significantly improved tread wear compared to a CB-functional low cis BR) as well as the Nd-COMCAT non-functional base polymer. The pyrazinecarbonitrile high cis BR shows significantly improved wearP22296WO1A; BSP183WO performance versus the control polymer in formulation #1, and slightly improved wear performance versus the control polymer in formulation #2. Furthermore, overall the tensile and viscoelastic properties are expected to have similar effects on tire performance between the polymers tested.

[0254] What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable modification and alteration of the above devices or methodologies for purposes of describing the aforementioned aspects, but one of ordinary skill in the art can recognize that many further modifications and permutations of various aspects are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the details description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim. The term “consisting essentially” as used herein means the specified materials or steps and those that do not materially affect the basic and novel characteristics of the material or method. If not specified above, the properties mentioned herein may be determined by applicable ASTM standards, or if an ASTM standard does not exist for the property, the most commonly used standard known by those of skill in the art may be used. The articles “a,” “an,” and “the,” should be interpreted to mean “one or more” unless the context indicates the contrary.

Claims

P22296WO1A; BSP183WO CLAIMS What is claimed is:

1. A polymer composition comprising: butadiene rubber polymers having polymer chain ends; the butadiene rubber polymers comprising a. a 1,4-cis content of 90% or greater; and b. a functional group comprising a heteroarylcarbonitrile molecule; wherein 30% or more of the polymer chain ends of the butadiene rubber polymers are functionalized with the functional group; wherein the butadiene rubber polymer has a nitrogen content of about 50 to about 500 ppm, preferably about 75 to about 400 ppm, more preferably about 100 to about 300 ppm, more preferably about 175 to 275 ppm.

2. The polymer composition of claim 1, wherein the heteroarylcarbonitrile molecule is represented by the formula θ-C≡N, where θ represents a heterocyclic group, preferably θ contains one or more nitrogen heteroatoms, and more preferably the molecule is pyrazinecarbonitrile.

3. The polymer composition of claim 1 or claim 2, wherein about 30% or more, preferably 40% or more of the polymer chain ends are functionalized with the functional group.

4. The polymer composition of any of claim 1-3, wherein the butadiene rubber polymer is catalyzed with an aged lanthanide-based catalyst, preferably a neodymium-based catalyst.

5. The polymer composition of claims 4, wherein the polymer composition contains a residue of the aged lanthanide-based catalyst.P22296WO1A; BSP183WO 6. A rubber composition for a tire tread comprising: a rubber component comprising a functionalized butadiene rubber in an amount of about 10 to about 60 phr, the functionalized butadiene rubber comprising a 1,4- cis content of 90% or greater, and a functional group comprising a heteroarylcarbonitrile molecule; and a natural rubber, polyisoprene rubber, and / or styrene-butadiene rubber; and a reinforcing filler component comprising carbon black in a range of about 25 to about 70 phr wherein the carbon black is a majority of the reinforcing filler component.

7. The rubber composition of claim 7, wherein the functionalized butadiene rubber is present in an amount of up to about 50 phr.

8. The rubber composition of claim 7 or claim 8, wherein over 50 phr of the rubber component is selected from the group consisting of: natural rubber, polyisoprene, styrene-butadiene rubber, and combinations thereof.

9. The rubber composition of any of claims 7-9, wherein the rubber component comprises about 20 to about 50 phr of the functionalized butadiene rubber.

10. The rubber composition of any of claims 7-10, wherein the rubber component further comprises about 40 to about 70 phr of natural rubber and / or polyisoprene; and about 5 to about 25 phr of styrene-butadiene rubber.

11. The rubber composition of any of claims 7-11, wherein the reinforcing filler component comprises 0 to about 30 phr of silica and about 30 to about 55 phr of the carbon black.

12. The rubber composition of any of claims 7-11, includes carbon black sourced from recycled materials and optionally, silica derived from rice husk ash.P22296WO1A; BSP183WO 13. The rubber composition of any of claims 7-12, wherein the heteroarylcarbonitrile molecule is represented by the formula θ-C≡N, where θ represents a heterocyclic group, preferably θ contains one or more nitrogen heteroatoms, and more preferably the molecule is pyrazinecarbonitrile.

14. A tire tread for application on tires having a load index of about 117 or more, the tread comprising: a rubber component comprising a functionalized butadiene rubber in an amount of about 10 to about 60 phr, the functionalized butadiene rubber comprising a 1,4-cis content of about 90% or greater, and a functional group comprising a heteroarylcarbonitrile molecule; a natural rubber, polyisoprene rubber, and / or styrene-butadiene rubber; and a reinforcing filler component comprising carbon black in a range of about 25 to about 70 phr wherein the carbon black is a majority of the reinforcing filler component.

15. The tire tread of claim 14, wherein the tire tread is coupled to a tire having a tire size, and the tire size is selected from the group consisting of: 9R17.5, 295 / 75R22.5, 11R24.5, 11R22.5, 255 / 70R22.5, 285 / 70R19.5, 285 / 75R24.5, 445 / 50R22.5, 315 / 80R22.5, 295 / 80R22.5, 385 / 65R22.5, 225 / 70R19.5, 295 / 60R22.5, 245 / 70R19.5, 245 / 70R17.5, 305 / 70R22.5, 275 / 70R22.5, 12.00R24, 12R22.5, 9R22.5, 10R22.5, 11.00R22, 10.00R20, 275 / 80R22.5, 215 / 75R17.5, 235 / 75R17.5, 365 / 70R22.5, 445 / 65R22.5, 425 / 65R22.5, 12R24.5, 265 / 70R19.5, 305 / 75R24.5, 265 / 75R22.5, 245 / 75R22.5, 9.00R20.

16. The tire tread of claim 14 or 15, wherein the heteroarylcarbonitrile molecule is represented by the formula θ-C≡N, where θ represents a heterocyclic group, preferably θ contains one or more nitrogen heteroatoms, and more preferably the molecule is pyrazinecarbonitrile.P22296WO1A; BSP183WO 17. The tire tread or rubber composition of any one of claims 1-15, wherein the rubber composition has a value for tan δ at 60 °C of 0.18 to 0.

26.

18. The tire tread or rubber composition according to any one of claims 1-16, wherein the rubber composition has an Eb at 25°C of at least about 425%.

19. The tire tread or rubber composition of any one of claims 1-18, wherein the rubber composition has a DIN abrasion of no more than 100 mm3.

20. A tire tread comprising the polymer composition or the rubber composition of any one of claims 1-13.

21. The tire tread or rubber composition of any one of claims 1-19, wherein the butadiene rubber polymer is not catalyzed with a methylaluminoxane catalyst, and contains essentially no residue of a methylaluminoxane catalyst.

22. The tire tread or rubber composition of any one of claims 1-18, 20 or 21, wherein the rubber composition has a DIN abrasion of no more than 90 mm3.

23. The tire tread or rubber composition of any one of claims 1-18, 20, or 21, wherein the rubber composition has a DIN abrasion of no more than 80 mm3.

24. The polymer composition of any of claims 1-6, wherein the butadiene rubber polymer has an Mw of 200,000 to 650,000 or an Mn of 125,000 to 300,000.

25. A method of making a functional polymer, the method comprising: (a) preparing a catalyst composition by combining a lanthanide-containing compound, an alkylating agent, and a halogen source; (b) aging the catalyst composition to form an aged catalyst composition, where said step of aging includes aging for more than 24 hours, preferably more than 5 days, more preferably more than 30 days;P22296WO1A; BSP183WO (c) combining the aged catalyst composition, additional alkylating agent, and conjugated diene monomer to be polymerized to form a polymerization system that produces a polydiene having a reactive chain end, wherein an amount of total aluminum employed relative to a total amount of the conjugated diene monomer is less than 5 mmol per 100 grams of the conjugated diene monomer, where said step of combining includes combining from about 0.001 to about 2 mmol of the lanthanide-containing compound per 100 grams of the conjugated diene monomer to be polymerized; and (d) introducing a functionalizing agent to the polymerization system to thereby prepare the functional polymer; wherein the functional polymer has a nitrogen content of about 50 to about 500 ppm, more preferably about 75 to about 400 ppm, preferably about 100 to about 300 ppm, more preferably about 175 to 275 ppm.

26. The method of claim 25, wherein a functional group of the functionalizing agent includes a heteroarylcarbonitrile group represented by the formula θ-C≡N, where θ represents a heterocyclic group, preferably θ contains one or more nitrogen heteroatoms, and more preferably the molecule is pyrazinecarbonitrile.

27. The method of claim 25 or 26, wherein a modification efficiency of the method is about 30% to about 65%.

28. The method of claim 25, 26, or 27 wherein the functionalizing agent does not include a siloxy group.

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