Functional polybutadiene and carbon black in rubber compounds

Abstract

A composition may include a functionalized polybutadiene having a functional group that has a carbon black reactive moiety, such as a heteroarylcarbonitrile and the polymer has a 1,4-cis content of 90% or greater. In an embodiment, about 10% or more of the polymer chains are functionalized with the functional group. The composition may include a reinforcing filler component comprising a carbon black with an iodine number of about 100 to about 155 and an OAN value of about 120 cm3 / 100 g to about 180 cm3 / 100 g.

Description

Functional Polybutadiene and Carbon Black in Rubber CompoundsCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional application 63 / 716,918, filed November 6, 2024, which is incorporated herein by reference.FIELD

[0002] This application is directed to carbon black filled rubber compositions and related methods. More specifically, it is directed to tire rubber composition comprising a functional polybutadiene and carbon black in particular.BACKGROUND

[0003] Tires comprise many components including, for example, road-contacting tread, sidewalls, carcass layers, bead apexes, and other components. 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 deterioration of another property (e.g., traction).Improvements in tire wear resistance are always desirable to provide a product that lasts longer.

[0004] Carbon black is a common component in rubber compositions, especially tire rubber compositions. It is often used in high ratios of the total compound weight. Providing a recyclable or sustainable carbon black that at least maintains comparable properties with compositions that include virgin carbon black is a challenge.

[0005] 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.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 is a plot showing the effect of different grades of carbon black on the fatigue tear behavior of (a) 0 Pz, (b) 17 Pz, (c) 37 Pz, and (d) 57 Pz example compounds.

[0007] Fig. 2 is a plot showing the effect of increasing the pyrazinecarbonitrile functional agent concentration on the fatigue tear behavior of example compounds with different types of carbon blacks (a) CB1, (b) CB2, (c) CB3 and (d) CB4.SUMMARY

[0008] The technology disclosed herein addresses the need for a balance of improved properties, such as, uniaxial tensile deformation, wear properties, viscoelastic performance and fatigue tear behavior in 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.

[0009] In some aspects, the techniques described herein relate to a rubber composition including: a rubber component including: a functionalized polybutadiene having a functional group including a carbon black reactive moiety and having a 1,4-cis content of 90% or greater and about 10% or more of polymer chains of the functionalized polybutadiene include the functional group; and a reinforcing filler component including a carbon black with an iodine number of about 100 to about 155 and an OAN value of about 120 cm3 / 100 g to about 180 cm3 / 100 g.

[0010] In some aspects, the techniques described herein relate to a rubber composition including: a rubber component including: a functionalized polybutadiene having a functional group including a heteroarylcarbonitrile group and having a 1,4-cis content of 90% or greater and about 15% to about 60% of polymer chains of the functionalized polybutadiene include the functional group; and a reinforcing filler component including a carbon black with an iodine number of about 80 to about 185 and an OAN value of about 70 cm3 / 100 g to about 200 cm3 / 100 g.

[0011] In some aspects, the techniques described herein relate to a tire component including: a rubber component including: a functionalized polybutadiene having a functional group including a carbon black reactive moiety and having a 1,4-cis content of 90% or greater and about 10% or more of polymer chains of the functionalized polybutadiene include the functional group; and a rubber component selected from the group consisting of: natural rubber, polyisoprene, polybutadiene, poly(styrene-butadiene), and combinations thereof; and a reinforcing filler including a reinforcing filler component including a carbon black with an iodine number of about 80 to about 185 and an OAN value of about 70 cm3 / 100 g to about 200 cm3 / 100 g; a sulfur crosslinking agent in an amount of about 0.1 to about 10 phr; and a resin or plasticizer in an amount of about 1 to about 35 phr. In an embodiment, the functional group including the carbon black reactive moiety is exclusive of a silica reactive moiety.

[0012] 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 topresent some concepts in a simplified form as a prelude to the more detailed description that is presented later.DETAILED DESCRIPTION

[0013] Functional polymers have been used to improve certain properties of rubber compositions. However, the type of functional polymer and the type of carbon black filler in the composition can produce improvement in parameters such as chain architecture, and final compound properties such as tensile strength, rolling resistance, heat generation, wear performance and fatigue behavior. Particular levels of functionalization in the composition can also produce a difference in a poor and a good balance of properties. In addition, it was discovered that there are certain carbon black grades that are more sensitive to the presence of functional group and can work in a synergistic way with the particular functional polymer. In certain embodiments, an excellent balance of properties is obtained with a modification efficiency of a carbon black reactive functional group (e.g., heteroarylcarbonitrile functional group) at about 10% to about 90%, such as, for example, about 15% to about 60%, about 20% to about 57%, about 10% to about 25%, or about 30% to about 45%, or about 50% to about 65% wherein these numbers represent percentage of the polybutadiene chains that are functionalized on a molar basis. Especially, when it is used with a suitable type of carbon black that has high structure.

[0014] 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 with a moiety that is reactive to carbon black. In an embodiment, the 1,4-cis content of the polybutadiene is about 90% or greater, such as about 95% to about 99.9%, or about 97% to about 99%. The functionalized polymer may have a Tg of less than -101 °C (e.g., - 101, -102, -103, -104, -105, -106, -107, -108, -109, -110, -111, or -112°C), such as -101 to -110 °C (e.g., -101, -102, -103, -104, -105, -106, -107, -108, -109, -110 °C).

[0015] In an embodiment, the functional group is a heteroarylcarbonitrile molecule, such as, for example, pyrazinecarbonitrile. In an embodiment, the modification efficiency is about 10% or greater, (i.e. about 10% or more of the polymer chain ends of the polybutadiene polymer are functionalized). For example, the modification efficiency may be about 17% or more, such as, about 45% to about 90%, or about 50% to about 65%.

[0016] In an embodiment, the functionalized polymer may have a total nitrogen content of, for example, about 10 to about 300 ppm, such as about 25 to about 200 ppm, about 50 to about 175 ppm, about 100 to about 200 ppm, or about 75 to about 150 ppm.

[0017] 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.

[0018] 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.

[0019] In an embodiment, at least about 20% of the polymer chains possess a reactive end, such as at least about 40%, at least about 60%, or at least about 80% of the polymer chains possess a reactive end. The reactive polymer can be reacted with heterocyclic nitrile compounds or mixtures thereof to form the functionalized polybutadiene polymer described herein.

[0020] 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 particular 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.

[0021] 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.

[0022] 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.

[0023] 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 may contain unsaturation and may be aromatic or nonaromatic. 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.

[0024] 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-l,2,3-triazol-4-yl, N-methyl-l,2,3-triazol-5-yl, N-methyl-l,2,4-triazol-3-yl, N-methyl-l,2,4-triazol-5-yl, l,2,4-triazin-3-yl, l,2,4-triazin-5-yl, l,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-pyrroh’n-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, l-methylindazol-3-yl, 1,5-naphthyridin-2-yl, l,5-naphthyridin-3-yl, 1,5- naphthyridin -4-yl, l,8-naphthyridin-2-yl, l,8-naphthyridin-3-yl, l,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, l,7-phenanthrolin-2-yl, 1,7-phenanthrolin-3-yl, l,7-phenanthrolin-4-yl, 1,10-phenanthrolin-2-yl, l,10-phenanthrolin-3-yl, 1,10-phenanthrolin-4-yl, 4,7-phenanthrolin-l-yl, 4,7-phenanthroh’n-2-yl, 4,7-phenanthrolin-3-yl, 1-phenazinyl, 2-phenazinyl, pyrrolidino, and piperidine groups.

[0025] 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-isobenzo[b]furyl, 3-isobenzo[b]furyl, 2 naphtho[2,3-b]furyl, and 3-naphtho[2,3-b]furyl groups.

[0026] Representative examples of heterocyclic groups containing one or more sulfur heteroatoms include 2-thienyl, 3-thienyl, 2-benzo[b]thienyl, 3-benzo[b]thienyl, l-isobenzo[b]thienyl, 3-isobenzo[b]thienyl, 2-naphtho[2,3-b]thienyl, and 3-naphtho[2,3-b]thienyl groups.

[0027] 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, l,2,3-oxadiazol-4-yl, l,2,3-oxadiazol-5-yl, l,3,4-oxadiazol-2-yl, l,2,3-thiadiazol-4-yl, l,2,3-thiadiazol-5-yl, l,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.

[0028] 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-l,2,3-triazole-4-carbonitrile, N-methyl-l,2,3-triazole-5-carbonitrile, N-methyl-l,2,4-triazole-3-carbonitrile, N-methyl-l,2,4-triazole-5-carbonitrile, l,2,4-triazine-3-carbonitrile, l,2,4-triazine-5-carbonitrile, l,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- 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-l-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, l,5-naphthyridine-2-carbonitrile, l,5-naphthyridine-3-carbonitrile, 1,5-naphthyridine-4-carbonitrile, 1,8-naphthyridine-2-carbonitrile, l,8-naphthyridine-3-carbonitrile, 1,8-naphthyridine-4-carbonitrile, 2-pteridinecarbonitrile, 4-pteridinecarbonitrile, 6-pteridinecarbonitrile, 7-pteridinecarbonitrile, l-methylbenzimidazole-2-carbonitrile, phenanthridine-6-carbonitri!e, 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, l,7-phenanthroline-3-carbonitrile, 1,7-phenanthroline-4-carbonitrile, 1,10-phenanthroline-2-carbonitrile, l,10-phenanthroline-3-carbonitrile, l,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.

[0029] 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.

[0030] 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, benzo[b]thiophene-3-carbonitrile, isobenzo[b]thiophene-l-carbonitrile, isobenzofb] thiophene-3 -carbonitrile, naphtho[2,3-b]thiophene-2-carbonitrile, and naphtho[2,3-b]thiophene-3-carbonitrile.

[0031] 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, l,2,3-oxadiazole-5-carbonitrile, 1,3,4-oxadiazole-2-carbonitrile, l,2,3-thiadiazole-4-carbonitrile, l,2,3-thiadiazole-5-carbonitrile, l,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.

[0032] 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-pyrirnidinedicarbonitrile, 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, l,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, 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.

[0033] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more nitrogen heteroatoms, include 2-pyridylacetoni trile, 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, l,7-phenanthrolin-2-ylacetonitrile, l,7-phenanthrolin-3-ylacetonitrile, 1,7-phenanthrolin-4-ylacetonitrile, l,10-phenanthrolin-2-ylacetonitrile, 1,10-phenanthrolin-3-ylacetonitrile, l,10-phenanthrolin-4-ylacetonitrile, 4,7-phenanthrolin-l-ylacetonitrile, 4,7-phenanthrolin-2-ylacetonitrile, 4,7-phenanthrolin-3-ylacetonitrile, 1-phenazinylacetonitrile, 2-phenazinylacetonitrile, pyrro ’dinoacetonitriie, and piperidinoacetonitrile.

[0034] Representative examples of heterocyclic nitrile compounds defined by the formula θ-R—C≡N, where θ contains one or more oxygen heteroatoms, include 2-furylacetonitrile, 3-furylacetonitrile, 2-benzo[b]furylacetonitrile, 3-benzo[b]furylacetonitrile, l-isobenzo[b]furylacetonitrile, 3-isobenzo[b]furylacetonitrile, 2-naphtho[2,3-b]furylacetonitrile, and 3-naphtho[2,3-b]furylacetonitrile.

[0035] 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.

[0036] 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.

[0037] 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, l,3,5-triazine-2,4-diacetonitrile, 1,2,4-triazine- 3.5-diacetonitrile, l,2,4-triazine-3,6-diacetonitrile, 2,3,4-pyridinetriacetonitrile, 2,3,5-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 l,2,4-triazine-3,5,6-triacetonitrile.

[0038] 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.

[0039] 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.

[0040] In an embodiment, the carbon black component is utilized in the rubber compositions in an amount of about 1 to about 80 phr. One or more than one carbon black may be utilized to comprise the about 1 to about 80 phr. In certain embodiments, the carbon black can be present in amounts ranging from about 1 to about 80 phr, including 1 to 80 phr, about 5 to about 45 phr, about 10 to 45 phr, about 25 to about 60 phr, about 30 to about 60 phr, about 35 to about 45 phr, or about 35 to about 45 phr.

[0041] In certain embodiments, the carbon black is the majority of the carbon black component of the compound, at least about 75% of the carbon black component of the compound, about 55% to about 95%, about 60% to about 80% of the carbon black component of the component. In certain embodiments, the carbon black is the entire filler component of the compound, or the majority of the filler component of the compound, at least about 25% of the filler component of the compound, or about 35% to about 95%, or about 50% to about 85% of the reinforcing filler component of the component. In certain embodiments, the rubber composition is essentially free of any carbon black other than the recycled carbon black.

[0042] In certain embodiments, the rubber composition is essentially free of any carbon black other than the designated carbon black. As used herein, the phrase "essentially free of any carbon blackother than..." means no more than 5 phr of other carbon black, preferably no more than 1 phr of other carbon black, including 0 phr of other carbon black.

[0043] In an embodiment, the carbon black may be a furnace black, channel black, or 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 channel blacks and conducting channel blacks. Other carbon blacks which can be utilized include acetylene blacks. Recycled carbon black can also be recycled versions of such virgin carbon blacks.

[0044] In an embodiment, the carbon black is a recycled carbon black or originates from a fossil fuel source, e.g., furnace black. In an embodiment, the carbon black can be replaced by or mixed with a sustainable carbon black, that is, one that is sourced from sustainable or otherwise non-fossil fuel sources, such as tire pyrolysis oil, plastic pyrolysis oil, pyrolyzed or otherwise processed vegetable or biomass feedstock, such as rice husk, bagasse, dead leaf, biochar, Palm kernel shells and oil palm fronds.

[0045] In an embodiment, the carbon black can be functionalized. In an embodiment, the carbon black has one or more of the following properties: a hydrogen release rate is 0.2% by mass or more, e.g., 0.22% to 0.5%, or 0.25% to 0.45%; a ratio of specific surface areas N2SA / CTAB is 1.2 to 1.5, e.g., 1.25 to 1.45, or 1.3 to 1.4; a nitrogen adsorption specific surface area (N2SA) is 160 to 300 m2 / g, e.g., 165 to 275, or 175 to 250; a dibutyl phthalate (DBP) absorption amount is 100 to 150 ml / 100 g, e.g., 105 to 145, or 110 to 14; an iodine adsorption specific surface area (IA) is 180 to 300 mg / g, 185 to 275, or 190 to 250; a tinting strength is 120 to 150, e.g., 125 to 145, or 130 to 135; and a light transmittance of toluene extract is 90 or more, e.g., 95 to 99.5, or 96 to 99.

[0046] Generally, suitable carbon blacks for use as a reinforcing filler in the rubber composition of certain embodiments include virgin carbon blacks, recycled carbon blacks, and sustainable carbon blacks.

[0047] In one embodiment, the carbon black has an iodine absorption in the range of 80 to 185 g / kg according to ASTM-D1510, such as about 90 to about 180 g / kg, about 95 to about 170, about 100 to about 165 g / kg, about 90 to about 110, about 130 to about 150, or about 145 to about 165. The Iodine adsorption is determined in accordance with ASTM D-1510.

[0048] In an embodiment, the carbon black has an oil absorption number (OAN) of about 70 cm3 / 100 g to about 200 cm3 / 100 g. In another embodiment, the OAN value is about 100 cm3 / 100 g toabout 180 cm3 / 100 g, about 110 cm3 / 100 g to about 170 cm3 / 100 g, about 120 cm3 / 100 g to about 160 cm3 / 100 g, about 115 cm3 / 100 g to about 125 cm3 / 100 g, about 130 cm3 / 100 g to about 150 cm3 / 100 g, or about 150 cm3 / 100 g to about to about 170 cm3 / 100 g. The OAN absorption is determined according to the standard ASTM D 2414-00. The OAN determined by this method may also be referred to as DBP (dibutyl phthalate) which is the type oil used in this method.

[0049] In an embodiment, the carbon black has a compressed sample oil absorption number (C-OAN) of 45 cm3 / 100 g to 1800 cm3 / 100 g. In another embodiment, the C-OAN value is 55 cm3 / 100 g to 140 cm3 / 100 g, 60 cm3 / 100 g to 120 cm3 / 100 g, 70 cm3 / 100 g to 115 cm3 / 100 g, or 80 cm3 / 100 g to 110 cm3 / 100 g. The C-OAN absorption is determined according to the standard 5 ASTM D 3493-21.

[0050] The carbon black may also have a surface area of at least about 20 m2 / g, including at least about 35 m2 / g up to about 300 m2 / g, about 50 m2 / g to about 200 m2 / g, and about 65 m2 / g to about 155 m2 / g, as determined by BET N2SA. The BET N2SA surface area can be determined in accordance with ASTM D-6556.

[0051] In an embodiment, the carbon black has a void volume as a function of mean pressure measured by a Dynamic Void Volume Analyzer (DVVA) according to ASTM D7854-16 has a value of about 25 to about 120, such as about 30 to about 90, about 40 to about 70, or about 45 to about 65.

[0052] Tint Strength can be determined by ASTM Test Procedure D3265-85a. In an embodiment, the tint of the carbon black can range from about 35 to about 120, such as, for example, about 40 to about 110, or about 50 to about 92.

[0053] In an embodiment, the carbon black may have a tinting strength (TINT)>0.363xCTAB+71.792. Tinting strength (TINT)>0.363xCTAB+71.792 may improve the reinforcing property of the rubber with the carbon black.

[0054] In an embodiment, the (TINT)<0.363xCTAB+ 71.792 and (TINT)> about 50. In this case, the dispersibility of the carbon black in the rubber may be improved and contribute to lowering the heat buildup of rubber. In case that TINT is more than about 50, strength and wear resistance may be improved.

[0055] In an embodiment, percent toluene discoloration of the carbon black can be measured by Item 8, B-process of JIS K6218:1997 and represented by a percentage to pure toluene. The percent toluene discoloration can be in a range of about 80% to about 125%, such as, about 90% to about 110%, or about 92% to about 103%.

[0056] In an embodiment, the carbon black in a 15% suspension in distilled water has a pH value of greater than about 6, greater than about 7, or greater than about 8. In an embodiment, the pH value of a 15% suspension of the particulate carbon material in distilled water is less than about 10, or less than about 9. ASTM D-1512 can be used to determine the pH.

[0057] In an embodiment, the carbon black has a DIG signal ratio in the Raman spectrum of 0.20 to 0.90, such as 0.40 to 0.75, such as 0.45 to 0.70. This provides a measure of the content of graphitic carbon.

[0058] A percent sulfur of the recycled carbon black can be determined by JIS K2213. Recycled carbon black may have a higher percent sulfur in general than a virgin carbon black. This may be in a range, for example, of about 0.8% to about 5%, such as, about 1% to about 3%, or about 1.2% to about 2%. Virgin or sustainable carbon black may have a lower sulfur content, such as, for example, about 0.01 to about 0.8%, 0.1 to about 0.6%, or about 0.2% to about 0.4%.

[0059] The properties disclosed above are with respect to distinct types of carbon blacks prior to any mixing. However, the same property ranges can be applied to mixed combinations of multiple types of blended carbon blacks.

[0060] In an exemplary embodiment, the heteroarylcarbonitrile-functionalized polymer and carbon black are ingredients in a rubber composition for tire components, in an exemplary embodiment, the rubber composition is filled with predominantly carbon black filler. For example, the reinforcing filler component may include the carbon black in a range of about 10 to about 100 phr, such as about 20 to about 80 phr, or about 30 to about 55 phr. Additional polymers, fillers and other components may be utilized in the rubber composition, for example, as disclosed below.

[0061] The subject rubber compositions can be 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.

[0062] 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, the term "reinforcing filler" is used to refer to a particulate materialthat has a nitrogen absorption specific surface area (N2SA) of more than about 100 m2 / g, and in certain instances 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 a 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 nonreinforcing filler (as discussed below) and a reinforcing filler.

[0063] 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 50 m2 / 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.

[0064] Additional carbon black filler can be added to the composition. However, in embodiments, the reinforcing filler component is exclusive of any additional carbon black or reinforcing filler that is not as described herein.

[0065] In an exemplary embodiment, the tire tread rubber compositions comprise at least one reinforcing silica filler in an amount of about 1 to about 50 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 20 phr (e.g., 80, 81, 82, 84, 85, 86, 88, or 90 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 ( / '.e., contains 0 phr of) reinforcing silica filler having a surface area outside the above-discussed ranges.

[0066] 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 1H-acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate and the like. Other suitable reinforcing silica fillers for use in certain embodiments include, but are not limited to, aluminum silicate, magnesium silicate (Mg2SiO4, MgSiO3 etc.), magnesium calcium silicate (CaMgSiO4), calcium silicate (Ca2SiO4 etc.), aluminum silicate (Al2SiO5, Al4.3SiO4.5H2O etc.), aluminum calcium silicate (Al2O3. CaO2SiO2, etc.), and the like. Among the listed reinforcing silica fillers, precipitated amorphous wet-process, hydrated silica fillers are often preferred. Such reinforcing silica fillers 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, can be used to characterize the 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, 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® 165GR).

[0067] 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 rubbercomposition, and, therefore, preventing this aggregation reduces the viscosity and improves the processability and blending of the rubber composition.

[0068] 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 alkoxycontaining), 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 pretreated silica can allow for two ingredients ( / .e., silica and a silica coupling agent) to be added in one ingredient, which generally tends to make rubber compounding easier.

[0069] Alkyl alkoxysilanes have the general formula R 1 n pSi(OR 11 )4-p where each R 11 is independently 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 comprises Cl to C20 aliphatic, C5 to C20 cycloaliphatic, or C6 to C20 aromatic; and each R 11 independently comprises Cl to C6 aliphatic. In certain exemplary embodiments, each R 1 n independently comprises C6 to C15 aliphatic and in additional embodiments each R 1 n independently comprises C8 to C14 aliphatic.Mercapto silanes have the general formula HS-R -Si(R )(R )2 where Ris a divalent organic group, R!4 is ahalogen atom or an alkoxy group, each R^ is independently 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 silyl group for reaction with silica in a sil ica-silane reaction and a blocking group B that replaces 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 form of an unsaturated heteroatom or carbon bound directly to sulfur via a single bond; R^ is Cl to Cg linearor branched alkylidene and each X is independently selected from the group consisting of Ci to C4 alkyl or Ci to C4 alkoxy.

[0070] 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.

[0071] 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 of bis(trialkoxysilylorgano)disulf ides 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.

[0072] 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.

[0073] 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 various blocked mercapto silanes can be used. A further example of a suitable blocked mercapto silane for use in certain exemplary embodiments is NKT™ silane (3- octanoylthio-l-propyltriethoxysilane), commercially available from Momentive Performance Materials Inc. of Albany, NY.

[0074] 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.

[0075] 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, 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, 3to 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.

[0076] In certain embodiments, the tire tread rubber composition comprises a reinforcing filler other than carbon black or silica ( / .e., an additional reinforcing filler). While one or more than one additional (i.e., non-carbon black and non-silica) 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 carbon black are present.

[0077] 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, clay (reinforcing grades), magnesium hydroxide, boron nitride, aluminum nitride, titanium dioxide, reinforcing zinc oxide, and combinationsthereof.

[0078] 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 nonreinforcing 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 specific surface area (N2SA) of less than about 20 m / g (including less than 20 m / g), and in certain embodiments less than about 10 m / g (including less than 10 m / 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 than10 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.

[0079] 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 polybutadiene (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 polybutadiene 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, or -112 °C), or -101 to -110 °C (e.g., -101, -102, -103, -104, -105, - 106, -107, -108, -109, -110 °C).

[0080] The 100 parts of elastomer component may also further comprise about 40 phr to about 90 phr, e.g., about 45 phr to about 75 phr, or 50 phr to 65 phr of the rubber component being selected from the group consisting of: natural rubber, polyisoprene, styrene-butadiene rubber, a different polybutadiene than the functionalized polybutadiene disclosed above, 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.

[0081] In an exemplary embodiment, the composition may comprise 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.

[0082] 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 about -30 to about -50 °C (e.g., 30, 30, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, or 50 °C). The at least one styrene-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 about 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.

[0083] 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 asdiscussed 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 (other than natural rubber or polyisoprene, styrene-butadiene rubber, and the functionalized polybutadiene or other polybutadiene) 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).

[0084] In an embodiment, the rubber composition comprises natural rubber and polybutadiene rubber in a ratio (NR: BR) of 25:75 to 75:25, such as 35:65 to 65:35, or 45:55 to 55:45.

[0085] In certain embodiments, the one or more additional rubbers 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 styrene-butadiene rubber 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%) a non-functionalized polybutadiene rubber having a cis bond content of at least about 95% and a Tg of about -101 °C or lower, or a combination thereof; or a combination of the foregoing types of rubbers.

[0086] 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 asTg.

[0087] In certain embodiments, the average Tg of the elastomer component is about -60 to about -90 °C (e.g., -60, -62, -64, -66, -68, -70, -72, -74, -76, -78, -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 ( / .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.

[0088] 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, 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.

[0089] 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.

[0090] 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%.

[0091] 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 ofthe 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.

[0092] 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 600,000 grams / mole or about 275,000 to about 550,000 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).

[0093] 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 140,000to about 475,000 grams / mole or about 150,000 to about 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 functionalized 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.

[0094] 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 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, in combination with at least one of the Mw ranges or Mn ranges described above, such as in combination with one of the Mw ranges and one of the Mn ranges described above.

[0095] 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 styrene-butadiene rubber is not extended with any oil).

[0096] The at least one styrene-butadiene rubber (i) having 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, hexamethylene imine (HMI).

[0097] 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 certain 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 blackreactive-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 combinationsthereof.

[0098] Non-limiting examples of nitrogen-containing functional groups that can be utilized in certain embodiments as a silica-reactive functional group in the atleast 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 silicareactive 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 functionalgroups.

[0099] 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 silicareactive 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 ( / .e., no emulsion styrene-butadiene rubber is present).

[0100] The elastomer component comprises a hi-cis functionalized polybutadiene rubber (BR) as described herein and can also include an additional BR. The following characteristics can apply to either the hi-cis functionalized polybutadiene or an additional BR.ZD

[0101] 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 and 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%, or 0.5%), such as less than 3% (e.g., 2.5%, 2%, 1.5%, 1%, or 0.5%), 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%, or 0.4%). 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.

[0102] 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, 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.

[0103] 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 polymervalues.

[0104] 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 polybutadiene is not extended with any oil).

[0105] (iii) Natural Rubber, Polyisoprene, Or A Combination Thereof

[0106] 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 to 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 l,000,000to 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 polystyrenestandard). 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).

[0107] In certain embodiments, the tire tread rubber composition comprises about 1 to about 35 phr (e.g., 5, 15, 20, 25, 29, 30, 31, 32, 33, 34, or 35 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 25-35 phr (e.g., 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35 phr) 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, 44, 45, 46, 48, or 50 °C). In certain embodiments, the tire tread rubber composition comprises 30-35 phr (e.g., 30, 31, 32, 33, 34, or 35 phr) of at least one hydrocarbon resin, such as an aromatic hydrocarbon resin, having a Tg of 30-50 °C, or a range within that range, as discussed infra. Hydrocarbon resin Tg can be determined by DSC, according to the procedure discussed above for elastomer Tg measurements. In certain embodiments, the at least one hydrocarbon resin has a Tg of about 35 to about 50 °C, 35- 50 °C (e.g., 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, or 50 °C), about 35 to about 45 °C, or 35-45 °C (e.g., 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, or 45 °C) and may be present in one of the foregoing discussed amounts.

[0108] 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 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 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 copolymerresins. 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, 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, alkylphenolformaldehyde 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.

[0109] 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 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. Incertain embodiments, the aromatic resin may include a hydrogenated form of one of the aromatic resins discussed above ( / .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 nothydrogenated.

[0110] 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.

[0111] 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.

[0112] 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 alphapinene 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., Ophr).

[0113] 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 toabout 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.

[0114] In certain embodiments, the hydrocarbon resin meets at least one of the following: (a) a Mw of 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, or4000 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 2500grams / 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, 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.

[0115] 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% toabout 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.

[0116] The tire tread rubber composition may comprise 0 to about 35 phr of liquid plasticizer (e.g., about 1 to about 35 phr, about 5 to about 25 phr, about 10 to about 20 phr, such as 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 phr), which may include at least one oil. In embodiments, the 11-20 phr of liquid plasticizer comprises at least one oil. In an embodiment, the 11-20 phr of liquid plasticizer consists of (only) at least one oil. In certain embodiments, the tire tread rubber composition comprises 15 to 20 phr of liquid plasticizer (e.g., 15, 16, 17, 18, 19, or 20 phr).

[0117] 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. 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 11-20 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 11-20 phr.

[0118] In certain embodiments, the tire tread rubber composition contains only free liquid plasticizer in an amount of 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.

[0119] 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 styrene-butadiene rubber for (i)) and according to embodiments wherein thestyrene-butadiene rubber (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 styrene-butadiene rubber is 10-50 parts oil per 100 parts of rubber (e.g., 10, 15, 20, 25, 30, 35, 40, 45 or 50 parts of oil per 100 parts or rubber), such as 10-40 parts oil per 100 parts or rubber, or 20-40 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 a styrene-butadiene rubber for (i) which styrene-butadiene rubber is used in an amount of 40 parts (the 40 parts being the amount of polymer of the oil-extended styrene-butadiene rubber, as discussed previously) in the overall tread rubber composition and, thus, the amount of oil contributed by the oil-extended styrene-butadiene rubber 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 styrene-butadiene rubber has a relatively high Mw and / or a relatively high Mooney viscosity.

[0120] In certain embodiments disclosed herein, the styrene-butadiene rubber as used in (i) is an oil-extended styrene-butadiene rubber having a polymer Mooney viscosity ML1+4 at 100 °C of at least 100. By polymer Mooney viscosity is meant the Mooney 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.

[0121] 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 ENERTHENE 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. Nonlimiting 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.

[0122] The liquid plasticizer may in certain embodiments include a non-oil plasticizer, nonlimiting examples of which include ether plasticizers, ester plasticizers, phosphate plasticizers, and sulfonate plasticizers. In those embodiments where a non-oil plasticizer is present, optionally 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), and fumaric acid esters. Exemplary phosphate plasticizers include those with a trihydrocarbyl phosphate and di-hydrocarbyl phosphate structures (where each hydrocarbyl is independently selected from alkyl of Cl to C12, Cl to C8, and aromatic of C6 to C12 (both substituted and un-substituted), when aromatic C6 is either substituted or un-substituted. More specifically, exemplaryphosphate 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.

[0123] 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).

[0124] 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).

[0125] 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 ester 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 Cl to C20 (e.g., Cl, C2, C3, C4, C5, C6, C7, C8, C9, CIO, Cll, 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.

[0126] 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, 45, 44, 43, 42, 41, 40, 39, 38, 37, or 36 phr, or a range from the foregoing, such as, 36-49 phr).

[0127] 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).

[0128] 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.

[0129] 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 agentconsists 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 suitable 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 about 0.1 to about 10 phr (e.g., about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), including about 1 to about 7.5 phr (e.g., 1, 2, 3, 4, 5, 6, 7, or 7.5 phr), including about 1 to about 5 phr (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 phr), and about 1 to about 3.5 phr (e.g., 1, 1.5, 2, 2.5, 3, or 3.5 phr).

[0130] 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).

[0131] 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 includingstearic 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 the structure (R^)(R^) NS(=C)N( R3)( R4) wherein each of R R2, R3, and R4are independently 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 together with one or more methylene groups (-CH2-) therebetween. In certain embodiments, the thiourea has one or two of R 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. Nonlimiting 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, l,3-di(o-tolyl)thiourea, l,3-di(p-tolyl)thiourea, l,l-diphenyl-2-thiourea, 2,5-dithiobiurea, guanylthiourea, 1-(1-naphthyl)-2-thiourea, 1-phenyl- 2-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, andN-N'-dimethylthiourea.

[0132] 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).

[0133] The particular steps involved in preparing the tire tread rubber compositions disclosed herein are generally those of conventionally practiced methods comprising mixing the ingredients in at least one non- productive master-batch stage and a final productive mixing stage. In certainembodiments, 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 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 nonproductive 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 mixingstage.

[0134] 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 being 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.

[0135] 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.

[0136] 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 190°C, such as, e.g., 140°C to 180°C, or 160°C to 175 °C. In certain embodiments, the tire tread rubber composition is prepared using a final productive mixing stageconducted 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 a 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.

[0137] In an embodiment, the polymer functional group modification may be defined by the following formula (I):C—OAN(I) x < ME x Iodine yIn formula (I) x is 0 and y is 2500, and ME represents the modification efficiency of the polymer, expressed as the percentage of chains that are functionalized on a molar basis. C-OAN denotes the oil absorption number in cm3 / 100 g, determined according to ASTM-D3493-21. The Iodine number is in g / kg and is measured based on ASTM-D1516. In other embodiments, for example, x = 100 and y = 2000, x = 300 and y = 1500, or x = 500 and y = 1000. Test conditions for these properties are disclosed herein.

[0138] In an embodiment the rubber composition conforms to a formula correlating the viscoelastic and mechanical properties defined by Formula (II):In formula II, a is 6 and b is 180, Tb is the tensile at break, M50% is the modulus at 50%, and tan 6 is tangent delta. In an embodiment, for example, a = 15 and b = 150, a = 30 and b = 120, or a = 60 and b = 100. Test conditions for these properties are disclosed herein. The Tb can be determined by ASTM D-412.

[0139] 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 -90 °C (e.g., -40, -42, -44, - 45, -46, -48, -50, -52, -54, -55, -56, -58, -60, -62, -64, -65, -66, -68, or -70 °C), -50 to -70 °C (e.g. -50, -52, -54, -55, -56, -58, -60, -62, -64, -66, -68, or -70 °C ), -45 to -65 °C (e.g., -45, -46, -48, -50, -52, -54, -55, -56, -58, -60, -62, -64, or -65 °C ), -40 to -60 °C (e.g., -40, -42, -44, -45, -46, -48, -50, -52, -54, -55, -56, -58, or -60 °C), -40 to -50 °C (e.g., -40, -41, -42, -43, -44, -45, -46, -47, -48, -49, or -50 °C), -50 to -60 °C (e.g., -50, -51, -52, -53, -54, -55, -56, -57, -58, -59, or -60 °C), -60 to -70 °C (-60, -61, -62, -63, -64, -65, -66, -67, -68, -69, or -70 °C), -45 to -55 °C (-45, -46, -47, -48, -49, -50, -51, -52, -53, -54, or -55 °C), or -55 to -65 °C (e.g., -55, -56, -57, -58, -59, -60, -61, -62, -63, -64, or -64 °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 instrument described below, operating in tension mode) generally following the guidelines of ASTM D5992-96 (2011) and using a temperature sweep (from -70 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 15 minutes at 170 °C, and using a vibratory method to estimate the Tg from the curve that results.

[0140] The use of carbon black in combination and functionalized polybutadiene described herein with other components of the tire tread rubber compositions can, in certain embodiments, result in an improvement in various properties as compared to a control rubber composition that replaces the functionalized polymer with the same polymer that is not functionalized and / or different carbon blacks.

[0141] In certain embodiments, the tire tread rubber composition exhibits an improvement in Mooney viscosity (1+4) of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 25%), or at least about 7%, such as about 7 to about 25%, about 7.5 to about 15%, or about 8 to 12.5%. Mooney viscosity (1+4) values may be for example about 30 to about 65, such as about 35 to about 60, or about 39 to about 7.

[0142] In certain embodiments, the tire tread rubber composition exhibits an improvement in modulus M15% at either room temperature (23°C) or 100°C, of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 25%), or at least about 7%, such as about 7 to about 25%, about 7.5 to about 20%, or about 8 to about 17%. M15 values at room temperature may be, for example, about 0.9 to about 1.1 MPa, such as about 0.92 to about 1.05, or about 0.95 to about 1.03. M15 values at 100°C may be, for example, about 0.8 to about 1.05 MPa, such as about 0.85 to about 1.02, or about 0.9 to about 1.0.

[0143] In an embodiment, the rubber composition exhibits an improvement in modulus M300%, at either room temperature (23°C) or 100°C, of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 25%), or at least about 10%, such as about 11 to about 25%, about 12 to about 20%, or about 13 to about 17%. M300 values at room temperature may be, for example, about 10 to about 15MPa, such as about 10.5 to about 14.5, or about 11 to about 14. M300 values at 100°C may be, for example, about 8 to about 12 MPa, such as about 8.5 to about 11.5, or about 9 to about 11.

[0144] In certain embodiments, the tire tread rubber composition exhibits an improvement in Eb at 100°C, with a particular carbon black (e.g., CB2 of the examples below) of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 25%), or at least about 7%, such as about 7 to about 25%, about 7.5 to about 20%, or about 8 to about 17%.

[0145] In certain embodiments, the tire tread rubber composition exhibits an improvement in Tb at 100°C, with a particular carbon black (e.g., CB2 of the examples below) of at least about 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 22%, 25%), or at least about 7%, such as about 7 to about 25%, about 7.5 to about 20%, or about 8 to about 20%.

[0146] In certain embodiments, the tire tread rubber composition exhibits an improvement in toughness (area under stress-strain curve) at room temperature and at 100°C, with particular carbon blacks of at least about 3% (e.g., 3%, 6%, 8%, 10%, or 15%) or at least about 4%, such as about 4 to about 12%, about 5 to about 11%, or about 6 to about 10%. Toughness values (in MPa at 23°C) may be, for example, about 50 to about 80, such as about 53 to about 70, or about 55 to about 65. Toughness values (in MPa at 100°C) may be, for example, about 25 to about 50, such as about 27 to about 45, or about 29 to about 43.

[0147] In certain embodiments, the tire tread rubber composition exhibits an improvement in tan delta at 60°C of at least about 3% (e.g., 3%, 6%, 8%, 10%, or 15%) or at least about 4%, such as 4 to about 12%, about 5 to about 11%, or about 6 to about 10%. Tan delta values may be, for example, about 0.1 to about 0.15, about 0.11 to about 0.145, or about 0.12 to about 0.142.

[0148] In certain embodiments, the tire tread rubber composition exhibits an improvement (reduction) in tan 8 / M50% of at least about 2% (e.g., 3%, 6%, 8%, 10%, 15%, or 20%) or at least about 4%, such as 4 to about 17%, about 5 to about 15%, or about 6 to about 13% compared to an identical control composition that replaces the functionalized polybutadiene with a same polymer that is not functionalized. Tan 8 / M50% values may be, for example, about 40 to about 75, about 45 to about 70, or about 45 to about 65.

[0149] In certain embodiments, wear resistance is improved, fatigue resistance is improved, and / or crack growth is delayed. These properties may be improved by at least about 2% (e.g., 3%, 6%, 8%, 10%, 15%, or 20%) or at least about 4%, such as 4 to about 17%, about 5 to about 15%, or about 6 to about 13%.

[0150] In an embodiment, a crack growth rate of the rubber composition after vulcanization as measured by dC / dN is reduced compared to an identical control composition that replaces the functionalized polybutadiene with a same polymer that is not functionalized, wherein C is crack size and N is a number of deformation cycles.

[0151] In certain embodiments, the tire tread rubber composition with functionalized polybutadiene and carbon black exhibits other equivalent properties to the control compositions. In other words, in exemplary embodiments, an improvement was realized in certain properties with no detriment to other properties.

[0152] While these properties may be measured by various methods, the values referred to herein for rolling resistance, snow or ice traction, wet traction, and dry handling refer to tan 6 values measured at the following temperatures and according to the following procedures. Tan 6 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 0.2% strain from-50 to -5 °C and 1% strain from -5 to 65 °C; collecting data approximately every 1 °C in order to provide measurements at temperatures of -30 °C, 0 °C, 30°C, and 60 °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 15 minutes at 170°C). A rubber composition's tan 6 at -30 °C is indicative of its snow or ice traction (also referred to herein as winter performance) when incorporated into a tire tread, tan 6 at 0 °C is indicative of its wet traction when incorporated into a tire tread, tan 6 at 30 °C is indicative of its dry handling when incorporated into a tire tread and its tan 6 at 60 °C is indicative of its rolling resistance when incorporated into a tire tread.

[0153] In certain embodiments, the rubber composition has a value for tan 6 at 60 °C of about 0.18 to about 0.26 (e.g., about 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, or 0.25), 0.18 to 0.22 (e.g., 0.18, 0.19, 0.2, 0.21, or 0.22), or 0.18 to 0.2 (e.g., 0.18, 0.19, 0.2). A tan 6 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 rolling resistance (as opposed to a tire with low rolling resistance which would generally be indicated by a tan 6 at 60 °C of less than or equal to 0.2). In certain embodiments, the value for tan 6 at 60 °C is combined with at least one of the following: (a) a value for tan 6 at -30 °C of no more than 2.5 times the tan 5 at 60 °C value (e.g., 2.5, 2.4, 2.2, 2.1, 2, 1.9, or 1.8 times ), 2.5 times and 2 times (e.g., 2.5, 2.4, 2.3, 2.2, 2.1, or 2 times) the tan 6 at 60 °C value; (b) a value for tan 6 at 30 °C of at least 1.4 times the tan 6at 60°C value (e.g., 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, or 2.2 times), 1.4 and 2 times (e.g., 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2 times) the tan 6 at 60 °C value, or 1.5 and 1.8 times (e.g., 1.5, 1.6, 1.7, or 1.8 times) the tan 6 at 60 °C value; or (c) a value for tan 6 at 0 °C of at least 2.2 times the tan 6 at 60 °C value (e.g., 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, or 3.2 times), 2.2 times to 3 times the tan 6 at 60 °C value (e.g., 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 times), or 2.3 times to 2.8 times the tan 6 at 60 °C value (e.g., 2.3, 2.4, 2.5, 2.6, 2.7, or 2.8 times); in certain such embodiments, the value for tan 6 at 60 °C is combined with each of (a), (b), and (c). In certain embodiments, one of the foregoing values for tan 6 at 60 °C (e.g., 0.18 to 0.25, 0.18 to 0.22, or 0.18 to 0.2) is combined with (a) a value for 6 at -30 °C of 2.5 times and 2 times (e.g., 2.5, 2.4, 2.3, 2.2, 2.1, or 2 times) the tan 6 at 60 °C value. In certain embodiments, one of the foregoing values for tan 6 at 60 °C (e.g., 0.18 to 0.25, 0.18 to 0.22, or 0.18 to 0.2) is combined with (b) a value for 6 at 30 °C of 1.4 and 2 times (e.g., 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2 times) the tan 6 at 60 °C value. In certain embodiments, one of the foregoing values for tan 6 at 60 °C (e.g., 0.18 to 0.25, 0.18 to 0.22, 0.18 to 0.2, etc.) is combined with (c) a value for 6 at 0 °C of 2.2 times to 3 times the tan 6 at 60 °C value (e.g., 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 times) the tan 6 at 60 °C value. In certain embodiments, one of the foregoing values for tan 6 at 60 °C (e.g., 0.18 to 0.25, 0.18 to 0.22, 0.18 to 0.2, etc.) is combined with the values tan 6 at -30 °C and the values for tan 6 at 30 °C.

[0154] In certain embodiments, the tire tread rubber composition has a value for tan 6 at 60 °C of 0.18 to 0.25, such as 0.18 to 0.22, or 0.18 to 0.21, and meets at least one of the following: (a) has a value for tan 6 at -30 °C of no more than 2.5 times the tan 6 at 60 °C value, or 2.5 times and 2 times the tan 6 at 60 °C value; (b) has a value for tan 6 at 30 °C of at least 1.4 times the tan 6 at 60 °C value, 1.4 times and 2 times the tan 6 at 60 °C value, or 1.5 times and 1.8 times the tan 6 at 60 °C value; or (c) has a value for tan 6 at 0 °C of at least 2.2 times the tan 5 at 60 °C value, 2.2 times and 3 times the tan 6 at 60 °C value, or 2.3 times and 2.8 times the tan 6 at 60 °C value.

[0155] 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 by 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, 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).

[0156] 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%.

[0157] In certain embodiments, the rubber composition has a room temperature Eb of at least 400% (e.g., 420%, 425%, 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%, r 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 of 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). The Tb can be determined by ASTM D-412.

[0158] In certain embodiments, the rubber composition has a hot Eb of at least 375%, (e.g., 375%, 380%, 385%, 390%, 395%, 400%, 405%, 410%, 415%, 420%, 425%, 430%, 435%, 440%, 445%, 450%, 455%, 460%, 465%, 470%, 475%, 480%, 485%, 490%, 495%, 499%, or more) or within a range of 375-499% or a sub-range within that range, such as at least 400% (e.g., 400%, 405%, 410%, 415%, 420%, 425%, 430%, 435%, 440%, 445%, 450%, 455%, 460%, 465%, 470%, 475%, 480%, 485%, 490%, 495%, 499%, or more) or within a range of 400-499% or a sub-range within that range. The foregoing hot Eb values refer to measurements made at 100 °C. Eb can be measured following the guidelines of 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.

[0159] In an embodiment, the tire tread rubber composition, as disclosed herein, will be utilized in a tire tread, for example, a TBR (truck and bus, radial tire tread, such as a TBR steer tire tread) or passenger and light truck tire. 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.

[0160] A TBR tire is one that has a load index (LI) corresponding to the min and max values in Table A below and is distinguished from a passenger tire (PSR) as shown below:Table A00161] In an embodiment, the TBR tire 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.

[0162] The composition can also be used in passenger and light truck tires.

[0163] 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 phrase "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.

[0164] 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.

[0165] Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, molarities, voltages, capacities, and so forth, as used in the specification or claims are to be understood as being modified by the term "about." Accordingly, unless otherwise implicitly orexplicitly indicated, or unless the context is properly understood by a person of ordinary skill in the art to have a more definitive construction, the numerical parameters set forth are approximations that may depend on the desired properties sought and / or limits of detection under standard test conditions / methods as known to those of ordinary skill in the art. When directly and explicitly distinguishing aspects of the present disclosure from discussed prior art, the stated numbers are not approximates unless the word "about" is recited.

[0166] 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-Heveo 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.

[0167] 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.

[0168] 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.

[0169] Unless otherwise indicated herein, the term "Mooney viscosity" refers to the Mooney viscosity, ML1+4. Mooney viscosity is measured prior to vulcanization or curing.

[0170] 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-Heveo 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.

[0171] 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.

[0172] 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.

[0173] EXAMPLES

[0174] Several compositions including natural rubber, polybutadiene, and carbon black filler were evaluated for uniaxial tensile strength, fatigue tear, wear, and viscoelastic properties.

[0175] Example A: Synthesis of Hi-Cis Polymer

[0176] 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 AI: 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 per hundred gram monomer (phgm)). The reactor jacket temperature was then set to 50 °C.

[0177] 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 isopropanol 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 polybutadiene is summarized in Table B.

[0178] Example B: Synthesis of Pyrazinecarbonitrile Functional high-cis BR

[0179] 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.

[0180] 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.

[0181] 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).

[0182] The coagulated polymer sample was dried by a drum-drier at 120 °C. Polymer characterization data of the polybutadiene of Examples 1 and 2 is summarized in Table B.Table B. Polymer Characterization of High-cis Polybutadiene (HCBR) Samples

[0183] 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 (K1M1a(a1+1) = K2M2a(a2+1)) where K = 0.0001249 and a = 0.72 for polystyrene and K = 0.000166 and a = 0.79 for high-cis BR.

[0184] 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 ppm 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)] / l,000,000).

[0185] The number of pyrazinecarbonitrile per avg polymer chain (aka modification efficiency) 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 pyrazinecarbonitrile 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.

[0186] Examples 1-4

[0187] A high cis neodymium butadiene rubber was synthesized in the same manner as disclosed in Examples A and B but with different concentrations of functional agent: 0% (being equal to unfunctionalized polybutadiene), 17%, 37% and 57%. These percentages are modification efficiency and represent the average number of functional groups per 100 polymer chains. The unfunctionalized polybutadiene has a 96% cis content and a Tg of -109 C. In addition to the polymers with different degrees of functionalization, four grades of carbon black with different primary particle sizes and filler structures were used in the compositions. Basic characteristics of the polymers and CB fillers are shown respectively in Table 1 and Table 2.

[0188] As reported in Table 1, number average (Mn), weight average (Mw) and polydispersity index PDI (Mw / Mn) of non-functional and pyrazinecarbonitrile-functional high cis neodymium butadiene rubber. Molecular weights were calculated using two different methods: Gel Permeation Chromatography (GPC) regarding linear high cis butadiene rubber (HCBR) (i.e., original standard during measurement was polystyrene, but calculations were performed to convert to a linear high-cis polybutadiene rubber polymer standard based on Mark-Houwink exponents) and Multi- Angle Light Scattering (MALS) that measures absolute molecular weight.Table 1

[0189] In Table 2, surface areas of carbon blacks used in the compositions were measured by the iodine adsorption method. This represents the quantity of iodine (in mg) that may be adsorbed on the surface of a specific mass of carbon black (in grams). The higher this number, the smaller the primary particle size of carbon black. Structure of blacks were measured using dibutyl phthalate (DBP) adsorption method representing volume of DBP (in cm3) by 100 g of carbon black. The higher this number, the higher (more complex and branched) the carbon black aggregates.Table 2

[0190] Example 9: Rubber Compositions

[0191] Mixing of rubber compositions for testing was accomplished in two stages, (master and final) using a 300-gram capacity internal mixer from Brabender. In the first step, polymers, carbon black, antioxidant and antiozonant were mixed. The ratio of natural rubber / polybutadiene was 50 / 50 in all the compounds. Per each 100 parts of rubber, 44 parts of carbon black was added. Curatives wereincorporated in the second step (final stage). Table 3 shows the conditions of mixing associated with each step.Table 3. Mixing conditions at Master (first) and Final (second) stages

[0192] In total, 16 combinations based on NR / BR / CB 50 / 50 / 44 were prepared. Variations were by polybutadiene type (4 types of polybutadiene, unfunctionalized, functionalized with pyrazinecarbonitrile 17%, pyrazinecarbonitrile 37% and pyrazinecarbonitrile 57%) and CB grade (4 types of CB1, CB2, CB3, and CB4). Samples were coded as xPz / CBy where x is the percentage of modification efficiency (0, 17, 37, 57) and y represents the CB grade (CB1, CB2, CB3 and CB4). For example, 37Pz / CB2 is a compound with 50 parts NR, 50 parts pyrazinecarbonitrile-high-cis polybutadiene rubber with modification efficiency of 37%, and 44 parts of CB2.

[0193] The prepared green (non-vulcanized) compounds were molded into the appropriate molds associated with different physical tests and then crosslinking were completed by keeping the sample at the high temperature of 145 °C for about 25 min. This cure condition was determined based on the moving die rheometer (MDR) cure experiment.

[0194] Example 10: Test Results

[0195] Mooney viscosity of compounds were measured at 130 °C in Mooney units. A preheating time of 1 min was used and the values of viscosity were recorded in Mooney unit, after 4 min of shearing the green compound. In addition, the ASTM standard large rotor is used for the measurements.

[0196] Bound rubber experiments were performed on green (non-vulcanized) compounds to quantify the weight percentage of the polymeric chains that are adsorbed onto the carbon black filler. This is a rough indication of the strength of the interaction between polymer and filler.

[0197] Uniaxial tensile experiments were done on cured samples at room temperature as well as 100 °C to measure the mechanical strength of samples and quantify the parameters such as modulus, tensile strength at break, tensile strain at break and toughness.

[0198] Temperature-sweep viscoelastic experiments were conducted on the cured samples to indirectly evaluate the rolling resistance and heat generation of tires made of these compounds. Tanδ at60 °C is an indication of rolling resistance and the higher this number, the more dissipative (resistant against rolling) the tire. The heat generation index is the ratio of tanδ at 100 °C to the tensile modulus at 50% strain (M50) at 100 °C, i.e. tanδ / M50 @ 100 °C. In embodiment. Both of these viscoelastic indicators are preferred to be low.

[0199] Wear performance of the cured samples were evaluated using a Lambourn abrasion tester. In this test, abradability (mg / J) is obtained as the slope of wear rate (mg / m) vs wear energy (J / m). Special calculations are done to account for the viscoelastic effects during rolling of the wheel as well as to convert the viscoelastic-corrected abradability data into the wear indicator that indicates projected mileage of the tire made of a similar compound for a certain application.

[0200] Single-edge notched tensile fatigue tests were carried out on the cured samples to measure the crack growth resistance of samples against dynamic tensile deformation. The result of this test is represented in dC / dN vs tearing energy figures. Here, C is the crack size, N is the number of deformation cycles, and dC / dN quantifies the rate of crack growth. At the lower tearing energies, crack length is almost constant and there are only small changes due to the chemical events such as degradation and oxidation. By increasing tearing energy, crack length increases and enters to a fastgrowing regime. Two parameters are important: onset of entering the fast-growing regime (where it is better to occur at higher tearing energies) and the slope of dC / dN vs. tearing energy curve at the second regime (where smaller is better).

[0201] Example 10

[0202] Mooney viscosity of the different compounds are represented in the 2nd row of Table 4. Depending on what variable chosen, there could be two approaches in comparing between Mooney viscosity of different compounds: i) viscosity values can be compared between compounds with the same type of CB while comparing increasing functional agent concentration, or ii) the effect of variation in the carbon black with the same polymer. The 4th to 7th rows compare the data by the first approach. For example, in the 4th row, the CB1 indices investigate the effect of increase in the functional agent concentration from 0% to 17% to 37% and then to 57%, while the type of CB is the same and equal to CB1. The indices in the 3rd row investigate the effect of change in the CB type with respect to the compound with CB1 for a same rubbery matrix. The same format of representing the data and approach in comparing between different compounds is used in following tables.Table 4: Mooney viscosity of compounds at 130 °C.

[0203] All the viscosities are in a useful range, and regardless of the increases observed in some cases, no significant processing challenges are indicated from this data. Compound viscosity ismore dependent on the polymer type rather than the carbon black grade. Standard deviation of Mooney viscosity when the CB typ e was changed was between 4.5% to 7%, while it is 7.3% to 10.4% when the polymer type is ch anged.

[0204] Using pyrazinecarbonitrile 17% and pyrazinecarbonitrile 37% with CB2 and CB3 canresult in a significant Mooney reduction (between -8% to -15%), and consequently processing benefits such as faster e x trusion. The ease of processing for these compounds were witnessed during mixing in the Brabe nder.

[0205] Example 11: Bound Rubber

[0206] Table 5 shows the absolute bound rubber values of different compounds along with their indexed values in a same fashion as Table 4.Table 5. Bound rubber values of different compounds

[0207] By calculating the average bound rubber value for each group of polymers withdifferent types of CB, i.e. for pyrazinecarbonitrile 0% group, the average of bound rubber values is the average of values of OPz / CBl, 0Pz / CB2, 0Pz / CB3 and 0Pz / CB4 (and so on for the other groups), it was generally seen that the interaction between polymer and CB increa ses by increasing concentration of functional agent.

[0208] In addition to the significant benefits that are available by introduction ofpyrazinecarbonitrile functional agent, bound rubber data suggest that selection of the right type of CB can be synergistic in achieving strong interaction b etween the functional polymer and CB (note the larger variation in the indices of 3rd row com pared to the indices of the 4th to 7th rows).

[0209] Functionality is beneficial when the carbon black grade that CB2 or CB3 (where there is12% to 18% increase in the bound rubber values compared to the non-functional counterparts). CB2and CB3 are the two blacks with the largest surface areas and highest structures. This finding suggests to use functional polymers to get better interaction, higher surface area (lower particle size) and higher structure are better ( based on the bound rubber data). Less reinforcing blacks are not as sensitive for polymer functionalization, and they can result in a comparable bound rubber independent of usingfunctionalized polymer. Reinforcing blacks using functional polymers can result in a significant increase in the bound rubber values.

[0210] Example 12: Uniaxial Tensile Test: Modulus

[0211] Results of the uniaxial tensile test at room temperature and 100 °C were tabulated and shown in Tables 6 to 9.

[0212] Elastic modulus at 15% (M15%) and 300% (M300%) strain of the Example rubber compositions at room temperature and 100 C° are shown in Table 6.Table 6. Elastic modulus at 15% (M15%) and 300% (M300%) strain

[0213] M15% (at RT and 100 °C) is independent of the type of polymer, i.e. functionalization does not appear to change M15%. M15% (at RT and 100 °C) is affected by CB type, and among different blacks, CB3 results in the highest modulus. Similar con clusions can be made regarding M300% at both temperatures.

[0214] Increase in the modulus of the samples with CB3 compared to the corresponding control is higher for M300% than for M15 %. In other words, modulus increase is magnified at higher strains. Unlike, M15%, where the e ffect of functionalization is not evident, in the case of M300% it seems that the functional polymers tend to have higher modulus.

[0215] Example 13: Elongation at break (Eb)

[0216] Elonga tion at break of different compounds at room temperature and 100 °C are shown in Table 7.Table 7. Elongation at break at room temperature and 100 C°

[0217] As shown in the Table, at room temperature, functionalization percentage has almost no effect on Eb. At 100 °C, functionalization effect on Eb depends on the type of carbon black. For CB1,CB3 and CB4, functionalization reduces Eb, while for CB2 Eb increases with functionalization.Independent of the type of polymeric matrix, CB3 results in the reduction of Eb.

[0218] Example 14: Tensile Stress at break (Tb)

[0219] Tensile stress at break of different compounds and their indexed values at room temperature and 100 °C are shown in Table 8.Table 8. Tensile stress at break (Tb) at room temperature and 100 C°

[0220] At room temperature, functionalization has almost no effect on Tb. At 100 °C,functionalization effect on Tb depends on the type of CB. For CB1 and CB3, functionalization has negligibleeffect on Tb. However, for CB4, functionalization reduces Tb, and for CB2, Tb increases with functionalization.

[0221] Example 15: Toughness

[0222] Toughness of the compounds and their indexed values at room temperature and 100 C° was quantified as the area under stress-strain curves and is presented in Table 9.Table 9. Toughness (as quantified by the area under strain-strain curve)00223] Functionalization can result in a significant improvement of toughness at hightemperatures only in simultaneous use with CB2 (especially in the case of pyrazinecarbonitrile 57%), otherwise (at low temperatures or in the case of use with other blacks) it is either ineffective or results in negative improvement (deteriorati on).

[0224] Example 16: Temperature-Sweep Viscoelastic Response

[0225] Table 10 shows the tanδ at 60 °C and the associated rolling resistance indices of the different compounds. Lower tanδ results in less rolling resistance. Therefore, rolling resistance indices (higher are better) were calculated as the inverse of tanδ (1 / tanδ) and then were normalized respect to the related control sample.Table 10. Tan δ at 60 °C and rolling resistance indexes

[0226] Introduction of pyrazinecarbonitrile functional agent improves rolling resistance. The higher the functional agent concentration the more the improvements. Com pounds with pyrazinecarbonitrile 57% provide the best performance regarding rolling resistance (having lowest valuesof tan 6), independent of the type of carbon black.

[0227] Carbon black CB2 results in less desirable rolling resistance indicator, independent of the polymeric matrix. CB3 and CB4 have the highest structure and tend to h ave better performance in all the matrices.

[0228] Example 17: Heat Generation

[0229] Heat generation index in TBR tires is calculated as the tan 6 / M50% at 100 °C. M50% is the modulus at 50% deformation. The lower this index, t he lower the heat generation (which is better). This index was calculated by using viscoelastic and tensile data and represented in Table 11 for the different compounds. The heat indicator is multiplied by 1000 for ease of reading. In embodiments, lowervalues / indices are preferred.Table 11. Heat generation indicator of tire (tanδ / M50%) at 100°C

[0230] Generally, functionalization results in reduction of heat generation. The polymer with the highest concentration of functional agent (pyrazinecarbonitrile 57%) is more effective in reducing heat generation, especially when it is used in combination with CB3.

[0231] The effect of variation in carbon black grade on reduction of heat generation can be as important as introducing functional agent. For example, by using CB3 with the non-functional BR, a similar index is obtained as in the example with pyrazinecarbonitrile 57% and CB4.

[0232] Example 18: Wear Performance

[0233] Wear performance was evaluated for the compounds. In general, wear performance was somewhat reduced with pyrazinecarbonitrile-functionalization. Especially when the functional polymer is mixed with CB1 or CB2. However, CB3 and CB4, having the highest structure, are almost insensitive for polymer variation, i.e., they show similar performance independent of being mixed with non-functional or functional polymer.

[0234] The non-functional polymer is more sensitive to CB type variation with respect to wear performance. The standard deviation of wear performance indicator of the OPz / CB compounds is much higher than that of the compounds where the functional polymer was used. The wear performance of the compounds with pyrazinecarbonitrile 37% were independent of the type of CB.

[0235] Example 19: Single Edge Notched Tensile Fatigue

[0236] Tensile fatigue responses of the tested compounds are shown in Figs. 1 and 2. Each panel in Fig. 1 compares the compounds with the same polymer matrix but different grades of carbon black. In the panels of Fig. 2, the same type of carbon black is used and effects of functional group concentration of high-cis polybutadiene rubber is varied and compared.

[0237] By comparing the fatigue tear response and wear data it is evident that there is a strong correlation between the fatigue tear and wear response of the compounds. A fatigue response with a larger tear energy at the onset of the crack initiation and a smaller slope in the fast crack growing regime is preferred in some embodiments. By comparing the fatigue curves and wear response of the compounds, it can be concluded that the smaller slope has a more significant role in improving wear response than the larger tear energy at the crack growth onset. Because of this, wear performance of OPz compounds (which have smaller slope in their fatigue curves) are better than the compounds with pyrazinecarbonitrile-functionalized BR, even though the compounds with pyrazinecarbonitrile-high-cis polybutadiene rubber have larger tear energy at the crack initiation onset. In addition, for the same reason, there is no significant difference between the wear response of 37Pz compounds (having same slope in fatigue curves), while wear performance of OPz compounds (with different slopes in the fatigue curves) are more sensitive to the type of carbon black.

[0238] Fig. 1 indicates that the fatigue behavior of compounds with non-functional polybutadiene (panel a) are most sensitive to the variation in the carbon black grade. Compounds with the pyrazinecarbonitrile-functionalization in general are less sensitive for the carbon black grade variation. Among different pyrazinecarbonitrile-functional polymers, pyrazinecarbonitrile 37% results in least sensitivity of fatigue response to the CB grade variation.

[0239] Fig. 2 indicates that the onset of the crack growth is delayed for the compounds with pyrazinecarbonitrile at 37%. For CB3, independent of the type of the polymeric matrix, at higher tearing energies crack growth rate significantly reduces and a plateau is observed in the dC / dN values (indicating steady state crack growth). This CB has the largest particle size. This may suggest that the large particle size of the carbon black has a positive effect in reducing crack growth rate.

[0240] Considering all the aspects (tensile properties, rolling resistance, heat generation, wear performance and fatigue behavior), overall, it seems that pyrazinecarbonitrile at 37% can offer the most excellent balance of performance compared to the other polymers (unfunctionalized, pyrazinecarbonitrile 17% and pyrazinecarbonitrile 57%). This is especially true, when pyrazinecarbonitrile 37% is used with a suitable type of CB such as CB3 and CB4, which have higher structure.

[0241] However, if improvements are targeted in a specific aspect rather that general excellently balanced behavior, other functionalization percentages and carbon blacks are indicated in the data provided to improve properties in that specific aspect.

[0242] 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 detailed 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 commonlyused 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

CLAIMSWhat is claimed is:

1. A rubber composition comprising:a rubber component including:a functionalized polybutadiene having a functional group comprising a carbon black reactive moiety and having a 1,4-cis content of 90% or greater and about 10% or more of polymer chains of the functionalized polybutadiene on a molar basis include the functional group; anda reinforcing filler component comprising a carbon black with an iodine number ofabout 100 to about 155 and an OAN value of about 120 cm3 / 100 g to about 180 cm3 / 100 g.

2. The rubber composition of claim 1, wherein the functional group is a heteroarylcarbonitrile.

3. The rubber composition of claim 1, wherein 20% or more of the polymer chains of the functionalized polybutadiene include the functional group.

4. The rubber composition of claim 1, further comprising natural rubber and / or polyisoprene.

5. The rubber composition of claim 1, wherein the carbon black is a majority of the reinforcing filler component.

6. The rubber composition of claim 1, wherein the functional group is pyrazinecarbonitrile.

7. The rubber composition of claim 1, wherein the carbon black has an iodine number of about 90 to about 110 and an OAN value of about 150 cm3 / 100 g to about 170 cm3 / 100 g.

8. The rubber composition of claim 1, wherein the carbon black has an iodine number of about 145 to about 165 and an OAN value of about 130 cm3 / 100 g to about 150 cm3 / 100 g.

9. A rubber composition comprising:a rubber component comprising:a functionalized polybutadiene having a functional group comprising a heteroarylcarbonitrile group and having a 1,4-cis content of 90% or greater and about 15% to about 60% of polymer chains of the functionalized polybutadiene include the functional group; anda reinforcing filler component comprising a carbon black with an iodine number of about 80 to about 185 and an OAN value of about 70 cm3 / 100 g to about 200 cm3 / 100 g.

10. The rubber composition of claim 9, wherein about 30% to about 45% of the polymer chains of the functionalized polybutadiene include the functional group.

11. The rubber composition of claim 10, wherein a crack growth rate of the rubber composition after vulcanization as measured by dC / dN is reduced compared to an identical control composition that replaces the functionalized polybutadiene with a same polymer that is not functionalized, wherein C is crack size, N is a number of deformation cycles.

12. The rubber composition of claim 11, wherein the carbon black has an iodine number of about 90 to about 110 and an OAN value of about 150 cnr’ / lOO g to about 170 cm3 / 100 g.

13. The rubber composition of claim 9, wherein the functional group is pyrazinecarbonitrile.

14. The rubber composition of claim 10, wherein the rubber composition has a tan 5 / M50 of about 45 to about 65, or wherein the tan δ / M50 of the rubber composition after vulcanization is reduced by at least about 2% compared to an identical control composition that replaces the functionalized polybutadiene with a same polymer that is not functionalized.

15. The rubber composition of claim 14, wherein the carbon black has an iodine number of about 90 to about 110 and an OAN value of about 150 cm3 / 100 g to about 170 cm3 / 100 g.

16. The rubber composition of claim 9, wherein about 50% to about 65% of the polymer chains of the functionalized polybutadiene include the functional group.

17. The rubber composition of claim 16, wherein the carbon black has an iodine number of about 145 to about 165 and an OAN value of about 130 cm3 / 100 g to about 150 cm3 / 100 g.

18. A tire component comprising:a rubber component comprising:a functionalized polybutadiene having a functional group comprising a carbon black reactive moiety and having a 1,4-cis content of 90% or greater and about 10% or more of polymer chains of the functionalized polybutadiene include the functional group; anda rubber component selected from the group consisting of: natural rubber, polyisoprene, polybutadiene, poly(styrene-butadiene), and combinations thereof;anda reinforcing filler comprising a reinforcing filler component comprising a carbon black with an iodine number of about 80 to about 185 and an OAN value of about 70 cm3 / 100 g to about 200 cm3 / 100 g;a sulfur crosslinking agent in an amount of about 0.1 to about 10 phr; anda resin or plasticizer in an amount of about 1 to about 35 phr.

19. The rubber composition of claim 1, wherein the functionalized polybutadiene has a functional group modification defined by the following formula (I):C - OAN( ) x < ME xIodine < ywherein x is 0 and y is 2500, ME represents the modification efficiency of the polymer, expressed as a percentage of chains that are functionalized on a molar basis, C-OAN denotes the oil absorption number of the carbon black in cm3 / 100 g, determined according to ASTM-D3493-21, Iodine is the iodine number of the carbon black in g / kg and is measured based on ASTM-D1516.

20. The rubber composition of claim 1, wherein the rubber composition conforms to Formula (II):Tb@100°C tanδ@60°Ca < - x - < bM50%@100°C tanδ@100°Cwherein a is 6 and b is 180, Tb is tensile strength at break, M50% is modulus at 50%, and tan 6 is tangent delta.

21. The rubber composition of claim 1, wherein the functional group comprising the carbon black reactive moiety is exclusive of a silica reactive moiety.

Images