Tire tread rubber composition

Abstract

Disclosed herein are tire tread rubber compositions comprising a specified elastomer component, reinforcing silica filler, carbon black, hydrocarbon plasticizer resin, liquid plasticizer, and a cure package. The elastomer component includes natural rubber, polyisoprene, or a combination thereof; and high cis polybutadiene rubber having a silica-reactive functional group. Use of the disclosed ingredients may result in a tire tread having particular properties, as discussed further herein.

Description

P24073W001TIRE TREAD RUBBER COMPOSITIONFIELD

[0001] The present application is directed to tire tread rubber compositions and to tires having a tread incorporating the tire tread rubber compositions.BACKGROUND

[0002] Certain tires that are available for sale are formulated for driving conditions that encountered by passenger vehicles (which are operated almost exclusively on roadways). Other tires that are available for sale are formulated for driving conditions that are encountered by vehicles which haul heavy loads and / or are driven in off-road terrains (e.g., non-paved surfaces) and may be designed with an LT or light truck designation. All of these tires comprise many components including a road-contacting tread. The particular ingredients used in the rubber composition which comprises the tire tread may vary. Formulation of tire tread rubber compositions is a complex science since changes to the ingredient formulation which result in an improvement in one property may result in deterioration of another property.SUMMARY

[0003] Disclosed herein are tire tread rubber compositions and tires having a tread incorporating the tire tread rubber compositions.

[0004] In a first embodiment, a tire tread rubber composition is disclosed. The composition is made of ingredients comprising: (a) 100 parts of an elastomer component comprising (i) 40-60 parts, preferably 45 to 55 parts of natural rubber, polyisoprene, or a combination thereof, and (ii) 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, and a silicareactive functional group, and wherein the elastomer component includes no more than 10 parts of styrene-butadiene rubber, preferably no more than 5 parts of styrene-butadiene rubber, more preferably 0 parts of styrene-butadiene rubber; (b) 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferably about 150 to about 300 m2 / g; (c) 30-60 phr, preferably 40-55 phr of carbon black; (d) 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C; (e) 1-10 phr, preferably 3-7 phr, of at least one liquid plasticizer, which preferably consists of at leastP24073W001 one oil; and (f) a cure package, wherein the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.

[0005] In a second embodiment, a tire tread rubber composition is disclosed. The composition is made of ingredients comprising: (a) 100 parts of an elastomer component comprising (i) 40-60 parts, preferably 45-55 parts of natural rubber, polyisoprene, or a combination thereof, and (ii) 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having the following formula (II):wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4- epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms , a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof, wherein the total amount of the natural rubber, polyisoprene, or a combination thereof of (a)(i) and the polybutadiene rubber of (a)(ii) is at least 90 parts, preferably at least 95 parts, more preferably 100 parts; (b) 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferablyP24073W001 about 150 to about 300 m2 / g; (c) 30-60 phr, preferably 40-55 phr of carbon black; (d) 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C, wherein the at least one hydrocarbon plasticizer resin is an aliphatic hydrocarbon resin; (e) 1-10 phr, preferably 3-7 phr, of at least one oil plasticizer, wherein the at least one oil plasticizer preferably includes plant oil; and (f) a cure package, and wherein the total amount of (b) and (c) is 70-90 phr, and the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.

[0006] In a third embodiment, which is a sub-embodiment of the first embodiment, a tire is disclosed which comprises (includes) the tire tread rubber composition of the first embodiment (as its tire tread).

[0007] In a fourth embodiment, which is a sub-embodiment of the second embodiment, a tire is disclosed which comprises (includes) the tire tread rubber composition of the second embodiment (as its tire tread).DETAILED DESCRIPTION

[0008] Disclosed herein are tire tread rubber compositions and tires having a tread incorporating the tire tread rubber compositions.

[0009] In a first embodiment, a tire tread rubber composition is disclosed. The composition is made of ingredients comprising: (a) 100 parts of an elastomer component comprising (i) 40-60 parts, preferably 45 to 55 parts of natural rubber, polyisoprene, or a combination thereof, and (ii) 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, and a silicareactive functional group, and wherein the elastomer component includes no more than 10 parts of styrene-butadiene rubber, preferably no more than 5 parts of styrene-butadiene rubber, more preferably 0 parts of styrene-butadiene rubber; (b) 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferably about 150 to about 300 m2 / g; (c) 30-60 phr, preferably 40-55 phr of carbon black; (d) 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C; (e) 1-10 phr, preferably 3-7 phr, of at least one liquid plasticizer, which preferably consists of at least one oil; and (f) a cure package, wherein the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.P24073W001

[0010] In a second embodiment, a tire tread rubber composition is disclosed. The composition is made of ingredients comprising: (a) 100 parts of an elastomer component comprising (i) 40-60 parts, preferably 45-55 parts of natural rubber, polyisoprene, or a combination thereof, and (ii) 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having the following formula (II):wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4- epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms , a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof, wherein the total amount of the natural rubber, polyisoprene, or a combination thereof of (a)(i) and the polybutadiene rubber of (a)(ii) is at least 90 parts, preferably at least 95 parts, more preferably 100 parts; (b) 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferably about 150 to about 300 m2 / g; (c) 30-60 phr, preferably 40-55 phr of carbon black; (d) 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to aboutP24073W00160 °C, wherein the at least one hydrocarbon plasticizer resin is an aliphatic hydrocarbon resin; (e) 1-10 phr, preferably 3-7 phr, of at least one oil plasticizer, wherein the at least one oil plasticizer preferably includes plant oil; and (f) a cure package, and wherein the total amount of (b) and (c) is 70-90 phr, and the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.

[0011] In a third embodiment, which is a sub-embodiment of the first embodiment, a tire is disclosed which comprises (includes) the tire tread rubber composition of the first embodiment (as its tire tread).In a fourth embodiment, which is a sub-embodiment of the second embodiment, a tire is disclosed which comprises (includes) the tire tread rubber composition of the second embodiment (as its tire tread). Definitions

[0012] The terminology as set forth herein is for description of the embodiments only and should not be construed as limiting the invention as a whole.

[0013] As used herein, the term "majority" refers to more than 50%.

[0014] As used herein, the abbreviation Mn is used for number average molecular weight.

[0015] As used herein, the abbreviation Mp is used for peak molecular weight.

[0016] As used herein, the abbreviation Mw is used for weight average molecular weight.

[0017] Unless otherwise indicated herein, the term "Mooney viscosity" refers to the Mooney viscosity, MLI+4. As those of skill in the art will understand, a rubber composition's Mooney viscosity is measured prior to vulcanization or curing.

[0018] As used herein, the term "natural rubber" means naturally occurring rubber such as can be harvested from sources such as Hevea rubber trees and non-Hevea sources (e.g., guayule shrubs and dandelions such as TKS). In other words, the term "natural rubber" should be construed so as to exclude synthetic polyisoprene.

[0019] 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.

[0020] 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 termP24073W001 polyisoprene should be construed as including polyisoprenes manufactured from natural sources of isoprene monomer.

[0021] 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.Tire Tread Rubber Composition

[0022] As mentioned above, the first-fourth embodiments disclosed herein are directed to tire tread rubber compositions made of specified ingredients. The subject rubber compositions are used in preparing treads for tires, generally by a process which includes forming of a tread pattern by molding and curing one of the subject rubber compositions. Thus, the tire treads will contain a cured form of one of the tire tread rubber compositions. The tire tread rubber compositions may be present in the form of a tread which has been formed but not yet incorporated into a tire and / or they may be present in a tread which forms part of a tire. In certain embodiments of the first and second embodiments, the tire tread rubber compositions are passenger vehicle tire tread rubber compositions. In certain other embodiments of the first and second embodiments, the tire tread rubber compositions are light truck tire tread rubber compositions. In certain embodiments of the third and fourth embodiments, the tire is a passenger vehicle tire which contains a cured form of the passenger vehicle tire tread rubber composition of the first or second embodiment disclosed herein as its road-contacting tread. In certain embodiments of the third and fourth embodiments, the tire is a light truck tire which contains a cured form of the light truck tire tread rubber composition of the first or second embodiment disclosed herein as its road-contacting tread. In certain embodiments of the first and second embodiment, the tire tread rubber composition is for use in or is the road-contacting portion of a tire tread.

[0023] According to the first-fourth embodiments disclosed herein, the Tg of the overall rubber composition may vary. The Tg of the overall rubber composition may be referred to as a compound Tg or as a rubber composition Tg. In certain embodiments of the first-fourth embodiments, the rubber composition has a compound Tg of -50 to -65 °C (e.g., -50, -51, -52, - 53, -54, -55, -56, -57, -58, -59, -60, -61, -62, -63, -64, or -65 °C ), preferably -55 to -61 °C (e.g., - 55, -56, -57, -58, -59, -60, or -61°C ). The compound Tg of a rubber composition can be measuredP24073W001 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.Elastomer Component

[0024] As mentioned above, according to the first-fourth embodiments, the tire tread rubber composition is made of ingredients comprising (including) 100 parts of an elastomer component. The ingredients of the elastomer component include natural rubber, polyisoprene rubber, or a combination thereof, and polybutadiene rubber. In other words, the elastomer component includes polybutadiene rubber and at least one of natural rubber or polyisoprene rubber. The total amount of 100 parts of elastomer or rubber is used so that the amount of other ingredients may be listed in amounts of phr or the number of parts per hundred parts of rubber (or 100 parts of the elastomer component). As a non-limiting example, for a rubber composition containing 45 parts of natural rubber, 55 parts of polybutadiene rubber, and 50 parts of reinforcing silica filler, the amount of silica filler can also be described as 50 phr.

[0025] As mentioned above, according to the first and third embodiments, the 100 parts of elastomer component comprises (includes) (i) 40-60 parts (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 parts), preferably 45 to 55 parts (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts) of natural rubber, polyisoprene, or a combination thereof; and (ii) 60-40 parts (e.g., 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, or 40 parts), preferably 55-45 parts (e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, or 45 parts), of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, and a silica-reactive functional group; and the elastomer component includes no more than 10 parts of styrene-butadiene rubber (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0 parts), preferably no more than 5 parts of styrene-butadiene rubber (e.g., 5, 4, 3, 2, 1, or 0 parts), more preferably 0 parts of styrene-butadiene rubber. In preferred embodiments of the first and third embodiments, the 100 parts of elastomer component comprises (includes)P24073W001(i) 45 to 55 parts (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts) of natural rubber, polyisoprene, or a combination thereof; and (ii) 55-45 parts (e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, or 45 parts), of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, and a silica-reactive functional group; and the elastomer component includes no more than 10 parts of styrene-butadiene rubber (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0 parts), preferably no more than 5 parts of styrene-butadiene rubber (e.g., 5, 4, 3, 2, 1, or 0 parts), more preferably 0 parts of styrene-butadiene rubber. In preferred embodiments of the first and third embodiments, (i) includes natural rubber. In more preferred embodiments of the first and third embodiments, (i) consists of (only) natural rubber and does not include any polyisoprene. In other embodiments of the first and third embodiments, (i) consist of (only) polyisoprene.

[0026] As also mentioned above, according to the second and fourth embodiments, the 100 parts of elastomer component comprises (includes) comprising (i) 40-60 parts (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 parts), preferably 45-55 parts (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts) of natural rubber, polyisoprene, or a combination thereof, and (ii) 60-40 parts (e.g., 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, or 40 parts), preferably 55-45 parts (e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, or 45 parts), of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having the following formula (II):

[0027] wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4-epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6,P24073W001 carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms , a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof; and the total amount of the natural rubber, polyisoprene, or a combination thereof of (a)(i) and the polybutadiene rubber of (a)(ii) is at least 90 parts (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100 parts), preferably at least 95 parts (e.g., 95, 96, 97, 98, 99, or 100 parts), more preferably 100 parts. In preferred embodiments the second and fourth embodiments, the 100 parts of elastomer component comprises (includes) (i) 45-55 parts (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts) of natural rubber, polyisoprene, or a combination thereof, and (ii) 55-45 parts (e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, or 45 parts), of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having the following formula (II): 3.,

[0028] wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4-epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group havingP24073W001 from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof; and the total amount of the natural rubber, polyisoprene, or a combination thereof of (a)(i) and the polybutadiene rubber of (a)(ii) is at least 90 parts (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100 parts), preferably at least 95 parts (e.g., 95, 96, 97, 98, 99, or 100 parts), more preferably 100 parts. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber (ii) has polymer chains bonded (only) to the functionalizing compound through the A1group. As a non-limiting example, when A1of the functionalizing compound is an epoxy group, a polymer chain is bonded to one of the carbons alpha to the oxygen of the epoxy ring. More specifically, according to such a bonding reaction, one polymer chain would bond to one of the carbon atoms alpha to the oxygen of the epoxy ring and the bonding would cause ring opening with conversion of the oxygen atom to OH. In certain embodiments of the second and fourth embodiments, the elastomer component includes no more than 10 parts of styrene-butadiene rubber (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0 parts), preferably no more than 5 parts of styrene-butadiene rubber (e.g., 5, 4, 3, 2, 1, or 0 parts), more preferably 0 parts of styrene-butadiene rubber.

[0029] In certain embodiments of the first-fourth embodiments, the average Tg of the elastomer component is -85 to -100 °C (e.g., -85, -86, -87, -88, -89, -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, or -100 °C), preferably -90 to -95 °C (e.g., -90, -91, -92, -93, -94, -95, -96, -97, -98, - 99, or -100 °C). The average Tg of the elastomer component can be calculated using the Tg of each rubber present in the 100 parts of elastomer component and accounting for their relative weight percentage. When one (or more) of the rubbers is oil-extended, only the amount of rubber (i.e., excluding any amount of oil) is utilized in calculating the average Tg of the elastomer component. When one (or more) of the rubbers is oil-extended, the Tg of the oil-extended rubberP24073W001 in its non-oil-extended form ( / .e., rubber only) is utilized in calculating the average Tg of the elastomer component.Natural Rubber or Polyisoprene (i)

[0030] As mentioned above, according to the first-fourth embodiments, the elastomer component of the tire tread rubber composition includes (i) 40-60 parts (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 parts), preferably 45-55 parts (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts) of natural rubber, polyisoprene, or a combination thereof. In certain preferred embodiments of the first-fourth embodiments, (i) consists (only) of natural rubber. In other embodiments of the first-fourth embodiments, (i) consists (only) of polyisoprene. When natural rubber is present for (i) 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 tread rubber compositions of the first-fourth embodiments, the natural rubber preferably has a Mw of 1,000,000 to 2,000,000 grams / mole (e.g., 1 million, 1.1 million, 1.2 million, 1.3 million, 1.4 million, 1.5 million, 1.6 million, 1.7 million, 1.8 million, 1.9 million, 2 million grams / mole); 1,250,000 to 2,000,000 grams / mole, or 1,500,000 to 2,000,000 grams / mole (as measured by GPC using a polystyrene standard). When natural rubber is utilized in the tread rubber compositions of the first-fourth embodiments, the Tg of the natural rubber may vary. Preferably, according to the first-fourth embodiments, when natural rubber is utilized it has a Tg of -65 to -80 °C (e.g., -65, -66, -67, -68, -69, -70, -71-, -72, -73, -74, - 75, -76, -77, -78, -79, or -80 °C), more preferably a Tg of -67 to -77 °C (e.g., -67, -68, -69, -70, -71, -72, -73, -74, -75, -76, or -77 °C). When polyisoprene is utilized in the tread rubber compositions of the first-fourth embodiments, the Tg of the polyisoprene may vary. Preferably, according to the first-fourth embodiments, when polyisoprene is utilized it has a Tg of -55 to -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), more preferably -58 to -74 °C (e.g., -58, -59, -60, -61, -62, -63, -64, -65, -66, -67, -68, -69, -70, -71, -72, -73, or -74 °C).Polybutadiene Rubber (ii)

[0031] As mentioned above, according to the first-fourth embodiments disclosed herein, the elastomer component of the tire tread rubber composition comprises (includes) (ii) 60-40P24073W001 parts (e.g., 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, or 40 parts), preferably 55-45 parts (e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, or 45 parts), of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group

[0032] According to the first and third embodiments disclosed herein, (ii) of the elastomer component consists of 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 (e.g., -102, -103, -104, -105, -106, -107, - 108, -109, -110, -111, -112 °C or less), preferably -101 or -110 °C (e.g., -102, -103, -104, -105, - 106, -107, -108, -109, or -110 °C), and a silica-reactive functional group. According to the second and fourth embodiments disclosed herein (and in certain embodiments of the first and third embodiments), (ii) of the elastomer component consists of 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 (e.g., -102, -103, -104, -105, -106, -107, -108, -109, -110, -111, -112 °C or less), preferably -101 or -110 °C (e.g., -102, -103, -104, -105, -106, -107, -108, -109, or -110 °C), a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having formula (II), as discussed in more detail below. In certain embodiments of the first-fourth embodiments, the Tg of the polybutadiene rubber (ii) is -101 to -110 °C (e.g., -101, -102, -103, -104, -105, -106, -107, -108, -109, or -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 of the first-fourth 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%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, or more). Since the cis bond content of the polybutadiene rubber (ii) is high ( / .e., at least 95%, as discussed above), the vinyl bond content will be low. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber of (ii) has a vinyl bond content of lessP24073W001 than 4% (e.g., 3.9%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, etc.), preferably less than 3% (e.g., 2.5%, 2%, 1.5%, 1%, 0.5%, etc.), more preferably less than 2% (e.g., 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, etc.). In certain embodiments of the first-fourth 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 of the first-fourth 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), preferably less than 1% by weight (e.g., 1%, 0.5%, or less) or 0% by weight syndiotactic 1,2-polybutadiene. Generally, according to the first-fourth embodiments, 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 functional group may be used for (ii). In certain embodiments of the first-fourth 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 functional group. In preferred embodiments of the first-fourth 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 10 parts, more preferably less than 5 parts or 0 parts.

[0033] According to the first and third embodiments disclosed herein the Mw and Mn of the polybutadiene rubber (ii) may vary. According to the second and fourth embodiments disclosed herein and in certain embodiments of the first and third embodiments disclosed herein the polybutadiene rubber (ii) has a Mw of 450,000 to 700,000 grams / mole (e.g., 450,000; 500,000; 550,000; 600,000; 650,000; or 700,000 grams / mole), preferably a Mw of 500,000 to 650,000 grams / mole (e.g., 500,000; 525,000; 550,000; 575,000; 600,000; 625,000; or 650,000 grams / mole). Mw ranges falling within the foregoing ranges such as 500,000 to 600,000 grams / mole, 550,000 to 600,000 grams / mole, 450,000 to 600,000 grams / mole, and 500,000 to 700,000 grams / mole can also be utilized in certain embodiments of the first-fourth embodiments. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber (ii) 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 grams / mole), preferably 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 280,000P24073W001 grams / mole). Mn ranges falling within the foregoing ranges such as 200,000 to 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 of the first-fourth embodiments. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber (ii) has a Mw of 450,000 to 700,000 grams / mole (or a range within the foregoing, as described above) and a Mn of 180,000 to 300,000 grams / mole (or a range within the foregoing, as described above). The foregoing Mw and Mn values for the polybutadiene of (ii) refer to values measured by GPC using a polystyrene standard. As well, the foregoing Mw and Mn values for the polybutadiene of (ii) refer to coupled Mw and coupled Mn rather than base polymer values.

[0034] In certain embodiments of the first-fourth embodiments disclosed herein, the at least one polybutadiene rubber (ii), as described above, is an oil-extended rubber, incorporating oil in an amount as discussed further below. In other preferred embodiments of the first-fourth embodiments disclosed herein, the at least one polybutadiene rubber (ii), as described above, is a non oil-extended rubber ( / .e., the BR is not extended with any oil). The use of the claimed amounts of the polybutadiene (ii) according to the first-fourth embodiments (preferably in combination with the other components of the tire tread rubber compositions according to the first-fourth embodiments) disclosed herein can in certain embodiments result in an improvement in wear and in rolling resistance as compared to a control rubber composition which uses 100 parts of natural rubber instead of a combination of natural rubber and polybutadiene having a cis bond content of at least 95% and a Tg of less than -101 °C and a silica-reactive functional group according to the first-fourth embodiments disclosed herein. The control rubber composition also preferably contains no component (b), (d), or (e), and contains more carbon black than as disclosed for the first-fourth embodiments (e.g., about 29% more with respect to the improvement in wear, as discussed below), but does include a cure package. In other words, the elastomer component of the control rubber composition will be 100 parts of natural rubber. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition exhibits an improvement in wear of at least 10% (e.g., 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or more), at least 20% (e.g., 20%, 25%, 30%, 35%, 40%, 45%, or more), at least 25% (e.g., 25%, 30%, 35%, 40%, 45%, or more), at least 30% (e.g., 30%, 35%, 40%, 45%, or more), at least 35% (e.g.,P24073W00135%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, or more), or even at least 40% (e.g., 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or more). As discussed further, infra, an improvement in wear can be measured by DIN abrasion values wherein a lower value (i.e., less material lost) indicates better wear. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition exhibits an improvement in rolling resistance (as evidenced by its value tan 6 at -60 °C, as discussed in more detail, infra) of at least 5% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 5-20%, 5-19%, 5-18%, 5-17%, 5-16%, 5-15%, 5-14%, 5-13%, 5-10%, etc., or more), preferably at least 10% (e.g., 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 10-20%, 10-19%, 10-18%, 10-17%, 10-16%, 10-15%, 10- 14%, 10-13%, etc., or more), more preferably at least 15% (e.g., 15%, 16%, 17%, 18%, 19%, 20%, 15-20%, etc., or more), or 5-20%, 5-15%, 10-20%, 10-15%, etc.

[0035] According to the first-fourth embodiments disclosed herein, the polybutadiene rubber of (ii) includes a silica-reactive functional group. According to the second and fourth embodiments and in certain embodiments of the first and third embodiments, the silica-reactive functional group results from a functional compound having the following formula (II):wherein A1represents a monovalent epoxy group; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms); Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms), a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms (e.g., 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms) or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms) or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms (e.g., 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, orP24073W00118 carbon atoms); b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof. As used herein, a partial condensation product refers to a product in which a part (not all) of a SiOR group in the hydrocarbyloxysilane compound is turned into a SiOSi bond by condensation. In certain embodiments of the first-fourth embodiments, at least one of the following is met: (a) Rcrepresents a divalent hydrocarbon group having 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 2 to 3 carbon atoms (e.g., 2 or 3 carbon atoms); (b) Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 1 to 2 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 8 carbon atoms; (c) Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms), 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), or 1 to 2 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 8 carbon atoms; in certain such embodiments, each of (a), (b) and (c) are met and Rc, Reand Rdare selected from one of the foregoing groups. As those of skill in the art will understand, the silica-reactive functional group may be added to the polybutadiene of (ii) by reacting the active terminal of the polymer chain with the compound having the formula (II).

[0036] According to the first-fourth embodiments, the particular epoxy group present in the formula (II) functionalizing compound can vary. In preferred certain embodiments of the first- fourth embodiments, the epoxy group ( / .e., A1in formula (II), above) is selected from glycidoxy, 3,4-epoxycyclohexyl, or a glycidyl group having 3-8 (e.g., 3, 4, 5, 6, 7, or 8), preferably 3-6 (e.g., 3, 4, 5, or 6), carbons overall (with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc). In certain embodiments of the first-fourth embodiments, the polybutadiene rubber of (ii) has a silica-reactive functional group resulting from use of a functionalizing compound of formula (II) where the epoxy group ( / .e., A1) is selected from glycidoxy. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber of (ii) has a silica-reactive functional group resulting from use of a functionalizing compound ofP24073W001 formula (II) where the epoxy group (i.e., A1) is selected from 3,4-epoxycylohexyl. In certain embodiments of the first-fourth embodiments, the polybutadiene rubber of (ii) has a silicareactive functional group resulting from use of a functionalizing compound of formula (II) where the epoxy group (i.e., A1) is selected from a glycidyl group having 3-8 (e.g., 3, 4, 5, 6, 7, or 8), preferably 3-6 (e.g., 3, 4, 5, or 6), carbons overall (with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc).. Non-limiting specific examples of such functionalizing compounds according to formula (II) which include an epoxy group include 2- glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, (2- glycidoxyethyl)methyldimethoxysilane, (2-glycidoxyethyl)methyldiethoxysilane, 3- glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl)- methyldimethoxysilane, (3-glycidoxypropyl)-methyldiethoxysilane, 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4- epoxycyclohexyl)ethyl(methyl)dimethoxysilane, 2-(3,4- epoxycyclohexyl)ethyl(methyl)diethoxysilane, and the like. Among them, 3- glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane are particularly preferred.Styrene-Butadiene Rubber

[0037] According to the first and third embodiments disclosed herein and in certain embodiments of the second and fourth embodiments disclosed herein, the elastomer component includes no more than 10 phr (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0 phr ), preferably no more than 5 phr (e.g., 5, 4, 3, 2, 1 or 0 phr) of styrene-butadiene rubber, more preferably 0 phr of styrene-butadiene rubber. Generally, styrene-butadiene rubber can be functionalized or nonfunctionalized and produced by solution polymerization or emulsion polymerization, and the term styrene-butadiene rubber is intended to encompass each of these unless stated to the contrary herein by the use of more specific terminology.Other Rubber(s) of the Elastomer Component

[0038] According to the second and fourth embodiments disclosed herein and in certain embodiments of the first and third embodiments disclosed herein, the total amount of the natural rubber, polyisoprene, or a combination thereof of (i) and the polybutadiene rubber of (ii)P24073W001 is at least 90 parts (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 parts), preferably at least 95 parts (e.g., 95, 96, 97, 98, 99, or 100 parts), more preferably 100 parts. When the total amount of the natural rubber or polyisoprene of (i) and the polybutadiene rubber of (ii) is less than 100 parts, the remaining amount of the 100 parts is made up by one or more additional rubbers. For example, when the total amount of the natural rubber, polyisoprene, or a combination thereof of (i) and the polybutadiene rubber of (ii) is 90 parts, 10 parts of the elastomer component is made up of one or more additional rubbers. According to the second and fourth embodiments disclosed herein and in certain embodiments of the first and third embodiments disclosed herein, the amount of additional rubber is no more than 10 parts (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0 parts), preferably no more than 5 parts (e.g., 5, 4, 3, 2, 1, or 0 parts), more preferably 0 parts.

[0039] According to the first-fourth embodiments, the particular rubber or rubbers used as the additional rubber(s) of the elastomer component (in those embodiments where additional rubber(s) is present) may vary. In certain embodiments of the first-fourth embodiments, the elastomer component includes one or more additional rubbers (in an amount as discussed above) selected from the group consisting of styrene-butadiene rubber, non-functionalized polybutadiene rubber having a cis bond content of at least 95%, polybutadiene rubber having a cis bond content of less than 95%, styrene-isoprene rubber, butadiene-isoprene-rubber, styrene- isoprene-butadiene rubber, butyl rubber (both halogenated and non-halogenated), neoprene (polychloroprene), ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM), and combinations thereof. In certain embodiments of the first-fourth embodiments, the elastomer component (and, thus, the overall tire tread rubber composition) is free of styrene-butadiene rubber (i.e., contains 0 phr of styrene-butadiene rubber). In certain embodiments of the first- fourth embodiments, the elastomer component (and, thus, the overall tire tread rubber composition) contains no more than 10 parts (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0 parts) of nonfunctionalized polybutadiene rubber having a cis bond content of at least 95%, preferably no more than 5 parts (e.g., 5, 4, 3, 2, 1, or 0 parts) of non-functionalized polybutadiene rubber having a cis bond content of at least 95% or even 0 parts of non-functionalized polybutadiene rubber having a cis bond content of at least 95%.P24073W001Fillers

[0040] 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 material that 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 non-reinforcing filler (as discussed below) and a reinforcing filler. In certain embodiments of the first-fourth 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 of the first-fourth 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.

[0041] As mentioned above, according to the first-fourth embodiments disclosed herein, the tire tread rubber composition includes a filler component comprising (b) 25-50 phr (e.g., 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 phr), preferably 30-40 phr (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 phr) of at least one reinforcing silica filler 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), preferably about 150 to about 300 m2 / g, and more preferably about 180 to about 250 m2 / g, and (c) 30-60 phr (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 phr), preferably 40-55 phr of carbon black (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,P24073W00152, 53, 54, or 55 phr). According to the first and third embodiments disclosed herein, the total amount of silica filler and carbon black filler may vary (according to the above-disclosed ranges). In certain embodiments of the first and third embodiments and according to the second and third embodiments, the total amount of silica filler and carbon black filler is 70 to 90 phr (e.g., 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90 phr), preferably 75 to 85 phr (e.g., 75, 76, 77, 78, 79, 80, 81, 82, 83, 84 or 85 phr).Reinforcing Silica Filler

[0042] As mentioned above, according to the first-fourth embodiments disclosed herein, the tire tread rubber compositions comprise (include) at least one reinforcing silica filler in an amount of 25-50 phr (e.g., 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 phr), preferably 30-40 phr (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 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), preferably about 150 to about 300 m2 / g, and more preferably about 180 to about 250 m2 / g. In certain preferred embodiments of the first- fourth embodiments, the tire tread rubber composition comprises (includes) at least one reinforcing silica filler (in an amount as discussed above) having a surface area of 150 to 300 m2 / g (e.g., 150, 160, 180, 200, 220, 240, 260, 280, or 300 m2 / g). In certain even more preferred embodiments of the first-fourth embodiments the tire tread rubber composition comprises (includes) at least one reinforcing silica filler (in an amount as discussed above) having a surface area of 180 to 250 m2 / g (e.g., 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, or 250 m2 / g) which should be understood as including intermediary ranges such as 180-240, 180- 230, 180-220, 180-210, 190-240, 190-230, 190-220, 190-210, etc. According to the first-fourth embodiments, one or more than one reinforcing silica filler in an amount and 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 referto the total amount of all reinforcing silica fillers. In certain embodiments of the first-fourth embodiments, only one reinforcing silica filler having a surface area and in an amount as discussed above is utilized. In preferred embodiments of the first-fourth 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 tireP24073W001 tread rubber composition can be understood as being free of (i.e., contains 0 phr of) reinforcing silica filler having a surface area outside the above-discussed ranges.

[0043] According to the first-fourth embodiments, the particular type of silica used for the at least one reinforcing silica filler of (b) may vary. Non-limiting examples of reinforcing silica fillers suitable for use in certain embodiments of the first-fourth embodiments include, but are not limited to, precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate and the like. Other suitable reinforcing silica fillers for use in certain embodiments of the first-fourth embodiments include, but are not limited to, aluminum silicate, magnesium silicate (Mg2SiO4, MgSiOs etc.), magnesium calcium silicate (CaMgSiCM), calcium silicate (Ca2SiO4 etc.), aluminum silicate (ALSiOs, AI4.3SiO4.5H2O etc.), aluminum calcium silicate (Al2O3.CaO2SiO2, etc.), and the like. Among the listed reinforcing silica fillers, precipitated amorphous wet-process, hydrated silica fillers are 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, is a preferred measurement for characterizing the reinforcing character of different reinforcing silica fillers. In certain embodiments of the first-fourth embodiments disclosed herein, the rubber composition comprises a reinforcing silica filler having a surface area (as measured by the BET method), as discussed infra. In certain embodiments of the first-fourth embodiments disclosed herein, the 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 of the first-fourth 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, H i-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 availableP24073W001 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® 165 GR).Silica Coupling Agent

[0044] In certain preferred embodiments of the first-fourth embodiments disclosed herein, one or more than one silica coupling agent may also (optionally) be utilized. In more preferred embodiments of the first-fourth embodiments, at least one silica coupling agent is utilized. Silica coupling agents are useful in preventing or reducing aggregation of the silica filler in rubber compositions. Aggregates of the silica filler particles are believed to increase the viscosity of a rubber composition, and, therefore, preventing this aggregation reduces the viscosity and improves the processability and blending of the rubber composition.

[0045] 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 of the first-fourth embodiments disclosed herein include those containing groups such as alkyl alkoxy, mercapto, blocked mercapto, sulfide-containing (e.g., monosulfide-based alkoxy-containing, disulfide-based alkoxy-containing, tetrasulfide-based alkoxy-containing), amino, vinyl, epoxy, and combinations thereof. In certain embodiments of the first-fourth embodiments, the silica coupling agent can be added to the rubber composition in the form of a pre-treated silica; a pre-treated silica has been pre-surface treated with a silane prior to being added to the rubber composition. The use of a pre-treated silica can allow for two ingredients ( / .e., silica and a silica coupling agent) to be added in one ingredient, which generally tends to make rubber compounding easier. In other embodiments of the first-fourth embodiments, the reinforcing silica filler used as (b) is not a pretreated silica.P24073W001

[0046] Alkyl alkoxysilanes have the general formula R10pSi(OR11)4-p where each R11is 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. Preferably p is 1. Generally, each R10independently comprises Ci to C20 aliphatic, C5 to C20 cycloaliphatic, or Ce to C20 aromatic; and each R11independently comprises Ci to Ce aliphatic. In certain exemplary embodiments, each R10independently comprises Ce to C15 aliphatic and in additional embodiments each R10independently comprises Cs to C14 aliphatic. Mercapto silanes have the general formula HS-R13-Si(R14)(R15)2 where R13is a divalent organic group, R14is a halogen atom or an alkoxy group, each R15is independently a halogen, an alkoxy group or a monovalent organic group. The halogen is chlorine, bromine, fluorine, or iodine. The alkoxy group preferably has 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 silica-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; R16is Ci to Ce linear or branched alkylidene and each X is independently selected from the group consisting of Ci to C4 alkyl or Ci to C4 alkoxy.

[0047] Non-limiting examples of alkyl alkoxysilanes suitable for use in certain embodiments of the first-fourth 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.

[0048] Non-limiting examples of bis(trialkoxysilylorgano)polysulfides suitable for use in certain embodiments of the first-fourth embodiments include bis(trialkoxysilylorgano) disulfidesP24073W001 and bis(trialkoxysilylorgano)tetrasulfides. Specific non-limiting examples of bis(trialkoxysilylorgano)disulfides include, but are not limited to, 3,3'-bis(triethoxysilyl propyl) disulfide, 3,3'-bis(trimethoxysilylpropyl)disulfide, 3,3'-bis(tributoxysilyl propyl)d isu Ifide, 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)d isu Ifide, 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 of the first-fourth 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 preferred embodiments of the first-fourth embodiments, the tire tread rubber composition includes a silica coupling agent in the form of a bis(trialkoxysilylorgano)polysulfides, more preferably a bis(trialkoxysilylorgano) disulfides.

[0049] Non-limiting examples of mercapto silanes suitable for use in certain embodiments of first-fourth embodiments disclosed herein include, but are not limited to, 1- mercaptomethyltriethoxysilane, 2- mercaptoethyltriethoxysilane, 3- mercaptopropyltriethoxysilane, 3- mercaptopropylmethyldiethoxysilane, 2- mercaptoethyltripropoxysilane, 18- mercaptooctadecyldiethoxychlorosilane, and mixtures thereof.

[0050] Non-limiting examples of blocked mercapto silanes suitable for use in certain embodiments of the first-fourth 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. Representative examples of the blocked mercapto silanes include, but are not limited to, 2- triethoxysilyl-1-P24073W001 ethylthioacetate; 2-trimethoxysilyl-l-ethylthioacetate; 2-(methyldimethoxysilyl)- 1- ethylth ioacetate; 3-trimethoxysilyl-l-propylthioacetate; triethoxysilylmethyl-thioacetate; trimethoxysilylmethylthioacetate; triisopropoxysilylmethylthioacetate; methyldiethoxysilyl methylthioacetate; methyldimethoxysilylmethylth ioacetate; methyldiisopropoxysilylmethylth ioacetate; dimethylethoxysilylmethylthioacetate; dimethylmethoxysilylmethylthioacetate; dimethylisopropoxysilylmethylth ioacetate; 2- triisopropoxysilyl-l-ethylthioacetate; 2-(methyldiethoxysilyl)-l-ethylthioacetate, 2-(methyldiisopropoxysilyl)-l- ethylthioacetate; 2-(dimethylethoxysilyl-l-ethylthioacetate; 2- (dimethylmethoxysilyl)-l- ethylthioacetate; 2-(dimethylisopropoxysilyl)-l-ethylthioacetate; 3- triethoxysilyl-l-propylthioacetate; 3-triisopropoxysilyl-l-propylthioacetate; 3- methyldiethoxysilyl-l-propyl-th ioacetate; 3-methyldimethoxysilyl-l-propylthioacetate; 3- methyldiisopropoxysilyl-l-propylthioacetate; 1- (2-triethoxysilyl-l-ethyl)-4- thioacetylcyclohexane; l-(2-triethoxysilyl-l-ethyl)-3- thioacetylcyclohexane; 2-triethoxysilyl-5- thioacetyl norbornene; 2-triethoxysilyl-4-thioacetylnorbornene; 2-(2-triethoxysilyl-l-ethyl)-5- thioacetyl norbornene; 2-(2-triethoxy-silyl-l- ethyl)-4-thioacetylnorbornene; l-(l-oxo-2-thia-5- triethoxysilylphenyl)benzoic acid; 6- triethoxysilyl-l-hexylthioacetate; l-triethoxysilyl-5- hexylthioacetate; 8-triethoxysilyl-l- octylthioacetate; l-triethoxysilyl-7-octylthioacetate; 6- triethoxysilyl-l-hexylthioacetate; 1- triethoxysilyl-5-octylthioacetate; 8-trimethoxysilyl-l- octylthioacetate; l-trimethoxysilyl-7- octylthioacetate; 10-triethoxysilyl-l-decylthioacetate; 1- triethoxysilyl-9-decylthioacetate; 1- triethoxysilyl-2-butylthioacetate; l-triethoxysilyl-3- butylthioacetate; l-triethoxysilyl-3-methyl-2- butylthioacetate; l-triethoxysilyl-3-methyl-3- butylthioacetate; 3-trimethoxysilyl-l- propylthiooctanoate; 3-triethoxysilyl-l-propyl-l- propylthiopalmitate; 3-triethoxysilyl-l- propylthiooctanoate; 3-triethoxysilyl-l- propylthiobenzoate; 3-triethoxysilyl-l-propylthio-2- ethylhexanoate; 3-methyldiacetoxysilyl-l- propylthioacetate; 3-triacetoxysilyl-l- propylthioacetate; 2-methyldiacetoxysilyl-l- ethylthioacetate; 2-triacetoxysilyl-l- ethylthioacetate; 1-methyldiacetoxysilyl-l-ethylth ioacetate; 1-triacetoxysilyl-l-ethyl-thioacetate; tris-(3-triethoxysilyl-l-propyl)trithiophosphate; bis-(3- triethoxysilyl-1- propyl)methyldithiophosphonate; bis-(3-triethoxysilyl-l- propyl)ethyldithiophosphonate; 3- triethoxysilyl-l-propyldimethylthiophosphinate; 3-P24073W001 triethoxysilyl-l-propyld iethylthiophosphinate; tris-(3-triethoxysilyl-l-propyl)tetrathiophosphate; bis-(3-triethoxysilyl-l propyl)methyltrithiophosphonate; bis-(3-triethoxysilyl-l- propyl)ethyltrithiophosphonate; 3- triethoxysilyl-l-propyldimethyldithiophosphinate; 3- triethoxysilyl-l-propyldiethyldithiophosphinate; tris-(3-methyldimethoxysilyl-l- propyl)trithiophosphate; bis-(3-methyldimethoxysilyl- l-propyl)methyldithiophosphonate; bis- (3-methyldimethoxysilyl-l-propyl)-ethyldithiophosphonate; 3-methyldimethoxysilyl-l- propyldimethylthiophosphinate; 3- methyldimethoxysilyl-l-propyldiethylthiophosphinate; 3- triethoxysilyl-l-propylmethylthiosulfate; 3-triethoxysilyl-l-propyl methanethiosulfonate; 3- triethoxysilyl-l-propylethanethiosulfonate; 3-triethoxysilyl-l-propyl benzenethiosulfonate; 3- triethoxysilyl-l-propyltolueneth iosulfonate; 3-triethoxysilyl-l-propylnaphthaleneth iosulfonate; 3-triethoxysilyl-l-propylxyleneth iosulfonate; triethoxysilylmethyl ethylthiosulfate; triethoxysilylmethylmethanethiosulfonate; triethoxysilyl methylethanethiosulfonate; triethoxysilylmethylbenzeneth iosulfonate; triethoxysilyl methyltoluenethiosulfonate; triethoxysilylmethylnaphthalenethiosulfonate; triethoxysilylmethylxylenethiosulfonate, and the like. 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 NXT™ silane (3- octanoylthio-l-propyltriethoxysilane), commercially available from Momentive Performance Materials Inc. of Albany, NY.

[0051] Non-limiting examples of pre-treated silicas ( / .e., silicas that have been pre-surface treated with a silane) suitable for use in certain embodiments of the first-fourth 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 ( / .e., 81-120 phr or about 90 to about 120 phr, etc.).

[0052] When a silica coupling agent is utilized in an embodiment of the first-fourth embodiments, the amount used may vary. In certain embodiments of the first-fourthP24073W001 embodiments, the rubber compositions do not contain any silica coupling agent. In other preferred embodiments of the first-fourth 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 ( / .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 preferred embodiments of the first-fourth embodiments, the ratio of the total amount of silica coupling agent to silica filler falls within a ratio of 1:10 to 1:20 ( / .e., 10 to 5 parts by weight per 100 parts of silica). In certain embodiments according to the first-fourth embodiments, the rubber composition comprises about 0.1 to about 10 phr silica coupling agent, including 0.1 to 10 phr (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), about 0.1 to about 10 phr, 0.1 to 8 phr, about 0.1 to about 8 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 10 phr, 1 to 10 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 phr), about 1 to about 8 phr, 1 to 8 phr (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, or 8 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 10 phr, 3 to 10 phr, about 3 to about 8 phr, 3 to 8 phr, about 3 to about 7 phr, 3 to 7 phr, about 3 to about 5 phr, or 3 to 5 phr. In preferred embodiments of the first-fourth embodiments, the rubber composition comprises silica coupling agent in an amount of 2 to 7 phr or one of the foregoing ranges falling within this range.Carbon Black Filler

[0053] According to the first-fourth embodiments disclosed herein, the tire tread rubber composition comprises (includes) 30-60 phr (e.g., 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 phr), preferably 40-55 phr of carbon black filler (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 phr). In preferred embodiments of the first-fourth embodiments, the foregoing amounts of carbon black filler should be understood to refer to reinforcing carbon black filler; and in certain such embodiments, the only carbon black filler present in the tire tread rubber composition is reinforcing carbon black filler. In other embodiments of the first-fourth embodiments, the amounts of carbon black filler should be understood to refer to non-reinforcing carbon black filler.P24073W001In yet other embodiments of the first-fourth embodiments, the foregoing limited amounts of carbon black filler should be understood to refer to all carbon black fillers (i.e., both reinforcing and non-reinforcing carbon black filler). In certain embodiments of the first-fourth embodiments, the only carbon black filler present is reinforcing carbon black filler and it is present in an amount as discussed above, i.e., 30-60 phr, preferably 40-55 phr.

[0054] In those embodiments of the first-fourth embodiments where carbon black filler is present, the particular type or types of carbon black utilized may vary. Generally, suitable carbon blacks for use as a reinforcing filler in the rubber composition of certain embodiments of the first-fourth embodiments include any of the commonly available, commercially-produced carbon blacks, including those having a surface area of at least about 20 m2 / g (including at least 20 m2 / g) and, more preferably, at least about 35 m2 / g up to about 200 m2 / g or higher (including 35 m2 / g up to 200 m2 / g). Surface area values used herein for carbon blacks are determined by ASTM D-1765 using the cetyltrimethyl-ammonium bromide (CTAB) technique. Among the useful carbon blacks are furnace black, channel blacks, and lamp blacks. More specifically, examples of useful carbon blacks include super abrasion furnace (SAF) blacks, high abrasion furnace (HAF) blacks, fast extrusion furnace (FEF) blacks, fine furnace (FF) blacks, intermediate super abrasion furnace (ISAF) blacks, semi-reinforcing furnace (SRF) blacks, medium processing channel blacks, hard processing channel blacks and conducting channel blacks. Other carbon blacks which can be utilized include acetylene blacks. In certain embodiments of the first-fourth embodiments, the rubber composition includes a mixture of two or more of the foregoing blacks. Preferably according to the first-fourth embodiments, if a carbon black filler is present it consists of only one type (or grade) of reinforcing carbon black. Typical suitable carbon blacks for use in certain embodiments of the first-fourth embodiments are N-110, N-220, N-339, N-330, N-351, N-550, and N-660, as designated by ASTM D-1765-82a. The carbon blacks utilized can be in pelletized form or an unpelletized flocculent mass. Preferably, for more uniform mixing, unpelletized carbon black is preferred.Other Reinforcing Fillers

[0055] In certain embodiments of the first-fourth embodiments, the tire tread rubber composition comprises a reinforcing filler other than carbon black or silica (i.e., an additionalP24073W001 reinforcing filler). While one or more than one additional reinforcing filler may be utilized, their total amount is preferably 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 preferred embodiments of the first- fourth embodiments, the tire tread rubber composition contains no additional reinforcing filler ( / .e., 0 phr); in other words, in such embodiments no reinforcing filler otherthan silica and carbon black are present.

[0056] In those embodiments of the first-fourth 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 of the first-fourth 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 combinations thereof.Non-Reinforcing Fillers

[0057] In certain embodiments of the first-fourth embodiments, the tire tread rubber composition further comprises at least one non-reinforcing filler. In other preferred embodiments of the first-fourth embodiments, the tire tread rubber composition contains no non-reinforcing fillers ( / .e., 0 phr). In embodiments of the first-fourth 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 "nonreinforcing filler" is used to refer to a particulate material that has a nitrogen absorption specific surface area (N2SA) of less than about 20 m2 / g (including less than 20 m2 / g), and in certain embodiments less than about 10 m2 / g (including less than 10 m2 / g). The N2SA surface area of a particulate material can be determined according to various standard methods including ASTM D6556. In certain embodiments, the term "non-reinforcing filler" is alternatively or additionally used to refer to a particulate material that has a particle size of greater than about 1000 nm (including greater than 1000 nm). In those embodiments of the first-fourth embodiments, wherein a non-reinforcing filler is present in the rubber composition, the total amount of non-P24073W001 reinforcing filler may vary but is preferably no more than 10 phr (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 phr), and in certain embodiments 1-10 phr, no more than 5 phr (e.g., 5, 4, 3, 2, or 1 phr), 1-5 phr, or no more than 1 phr.Plasticizing System

[0058] As used herein, the term "plasticizing system" is intended to refer to the combination of the at least one hydrocarbon plasticizer resin and at least one liquid plasticizer that is present in the tire tread rubber composition of the first-fourth embodiments disclosed herein. The at least one hydrocarbon plasticizer resin ( / .e., (d) in the claims) is discussed in more detail below. Similarly, the at least one liquid plasticizer (i.e., (e) in the claims) is discussed in more detail below. According to the first-fourth embodiments, the total amount of (d) and (e) is 15-30 phr (e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 1 , 28, 29 or 30 phr), preferably 18- 27 phr (e.g., 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 phr). In certain embodiments of the first-fourth embodiments, the plasticizing system is present in a total amount of 15-30 phr (e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 phr), preferably 18-27 phr (e.g., 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 phr); in certain such embodiments, the plasticizing system consists of (only) at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C, as discussed in more detail below, and at least one liquid plasticizer, as also discussed in more detail below.Hydrocarbon Plasticizer Resin

[0059] As mentioned above, according to the first-fourth embodiments disclosed herein, the tire tread rubber composition comprises (includes) 10-25 phr (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 phr), preferably 15-20 phr (e.g., 15, 16, 17, 18, 19, or 20 phr) of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C. As used herein, the term hydrocarbon plasticizer resin refers to a resin that acts as a plasticizer in the tire tread rubber composition. As one of skill in the art will understand plasticizers are generally used in tread rubber compositions to improve processability (e.g., mixing) and will generally lower the viscosity (e.g., Mooney viscosity) of a rubber composition. Accordingly, as used herein, the term hydrocarbon plasticizer resin refers to a hydrocarbon resin that reduces the viscosity of the tireP24073W001 tread rubber composition. Such resins can be contrasted with homogenizing agents which are discussed in more detail below.

[0060] As mentioned above, the Tg of the hydrocarbon plasticizing resin of (d) is about 40 to about 60 °C, 40-60 °C (e.g., 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 °C), about 45 to about 60 °C, 45-60 °C (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 °C), about 45 to about 55 °C, or 45-55 °C (e.g., 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 °C). Hydrocarbon resin Tg (both for plasticizing resins and for dispersing agents containing one or more hydrocarbon resin) can be determined by DSC, according to the procedure discussed above for elastomer Tg measurements.

[0061] As mentioned above, according to the first and third embodiments disclosed herein, the tire tread rubber composition includes (includes) 10-25 phr (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 phr), preferably 15-20 phr (e.g., 15, 16, 17, 18, 19, or 20 phr) of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C. According to the second and fourth embodiments, and in certain embodiments of the first and third embodiments, the at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C comprises (or in certain embodiments consists of) an aliphatic resin.

[0062] In certain embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin of (d) comprises an aliphatic resin optionally in combination with one or more additional resins selected from cycloaliphatic, aromatic, and terpene resins; in those embodiments of the first-fourth embodiments wherein one or more additional resins are present, the total amount of such additional resin(s) is preferably 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, preferably no more than 5% by weight of the overall amount of hydrocarbon plasticizer resin of (d )). In other embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin of (d) consists of (only) an aliphatic resin or aliphatic resins. When an aliphatic resin is used, one or more than one aliphatic resin may be utilized. In certain embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin excludes any terpene resin (i.e., 0 phr of terpene resin is present in the tread rubber composition). As used herein, the term aliphatic resin should be understood to include both aliphatic homopolymer resins and aliphaticP24073W001 copolymer resins. An aliphatic copolymer resins refers to a hydrocarbon plasticizer resin which comprises a combination of one or more aliphatic monomers in combination with one or more other (non-aliphatic) monomers, with the largest amount of any type of monomer being aliphatic. An aliphatic copolymer resin would include a hydrocarbon plasticizer resin having 45% by weight aliphatic monomers, in addition to 25% by weight cycloaliphatic monomers and 30% by weight aromatic monomers as well as a hydrocarbon plasticizer resin having 55% by weight aliphatic monomers, in addition to 30% by weight cycloaliphatic monomers and 15% by weight aromatic monomers. In certain embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin of (c) comprises one or more aliphatic copolymer resins having a majority by weight of all monomers being aliphatic (e.g., 51%, 55%, 60%, 65%, etc.). Non-limiting examples of aliphatic resins suitable for use as the hydrocarbon plasticizer resin in certain embodiments of the first- fourth embodiments include C5 fraction homopolymer or copolymer resins, C5 fraction / C9 fraction copolymer resins, C5 fraction / vinyl aromatic copolymer resins (e.g., C5 fraction / styrene copolymer resin), C5 fraction / cycloaliphatic copolymer resins, C5 fraction / C9 fraction / cycloaliphatic copolymer resins, , and combinations thereof. Non-limiting examples of cycloaliphatic monomers include, but are not limited to cyclopentadiene ("CPD") and dicyclopentadiene ("DCPD"). Exemplary aliphatic 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.

[0063] In certain embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin of (d) comprises a C5 fraction homopolymer resin, C5 fraction copolymer resin (e.g., C5 in combination with one or more of the above-mentioned monomers such as C9 fraction, DCPD, CPD, and combinations thereof), or a combination thereof. In other embodiments of the first-fourth embodiments, the hydrocarbon plasticizer resin of (d) consists of a C5 fraction homopolymer resin, C5 faction copolymer resin (e.g., C5 in combination with one or more of the above-mentioned monomers such as C9 fraction, DCPD, CPD, and combinations thereof), or a combination thereof.P24073W001Liquid Plasticizer

[0064] As discussed above, according to the first and third embodiments disclosed herein, the tire tread rubber composition includes as (e) 1 to 10 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), preferably 3-7 phr (e.g., 3, 4, 5, 6, or 7 phr)) of at least one liquid plasticizer, which preferably consists of at least one oil. According to the second and fourth embodiments disclosed herein and in certain embodiments of the first and third embodiments, the tire tread rubber composition includes as (e) 1 to 10 phr (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), preferably 3-7 phr (e.g., 3, 4, 5, 6, or 7 phr)) of at least one oil plasticizer, wherein the at least one oil plasticizer preferably includes plant oil. The phrase liquid plasticizer should be understood to refer to plasticizers that are liquid at 25 °C, including, but not limited, to oils and ester plasticizers.

[0065] 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.

[0066] According to the first-fourth embodiments, when one or more oils are present in the rubber composition as at least a portion of the liquid plasticizer (e), various types of processing and extender oils may be utilized, 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, ERGONP24073WQ01H2000, CROSS C2000, CROSS C2400, and SAN JOAQUIN 2000L. Exemplary low PCA oils also include various plant-sourced oils such as can be harvested from vegetables, nuts, and seeds. Non-limiting examples include, but are not limited to, soy or soybean oil, sunflower oil (including high oleic sunflower oil), safflower oil, corn oil, linseed oil, cotton seed oil, rapeseed oil, cashew oil, sesame oil, camellia oil, jojoba oil, hemp 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.

[0067] In those embodiments of the first-fourth embodiments wherein one or more oils are present in the rubber composition as at least a portion of the liquid plasticizer (e), the Tg of the oil or oils used may vary. In certain embodiments of the first-fourth 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).

[0068] Preferably according to the first-fourth embodiments, the tire tread rubber composition contains less than 5 phr (e.g., 4.5, 4, 3, 2, 1, or 0 phr) of IVIES or TDAE oil, preferably no MES or TDAE oil {i.e., 0 phr). In certain embodiments of the first-fourth embodiments, the rubber composition contains no petroleum oil {i.e., 0 phr) and instead any oil utilized is a plant oil. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition contains soybean oil in one of the above-mentioned amounts; in certain such embodiments the only oil included is soybean oil. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition contains no sunflower oil {i.e., 0 phr). In other embodiments of the first-fourth embodiments, the only oil included is sunflower oil.

[0069] In certain embodiments of the first-fourth embodiments, the tire tread rubber composition includes one or more ester plasticizers for at least a portion of the liquid plasticizer (e). Ester plasticizers are generally liquid at room temperature. In other embodiments of the first-fourth embodiments, the liquid plasticizer (e) does not contain any ester plasticizer (i.e., 0 phr of ester plasticizer is present). Suitable ester plasticizers are known to those of skill in the artP24073W001 and include, but are not limited to, phosphate esters, phthalate esters, adipate esters and oleate esters ( / .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 Ci to C20 (e.g., Ci, C2, C3, C4, C5, Ce, C7, Cs, C9, C10, CH, C12, C13, C14, C15, Ci6, C17, Cis, C19, C20), or Ce 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 tire tread rubber composition containing such ester plasticizer at least in part due to the relatively low Tg of ester plasticizers. In certain embodiments of the first-fourth 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 of the first-fourth embodiments wherein one or more ester plasticizers is utilized the amount utilized may vary. In certain embodiments of the first-fourth embodiments, one or more ester plasticizers are utilized for at least 10% by weight (e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or even 100% by weight), at least 25% by weight (e.g., 25%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or even 100% by weight), at least 50% by weight (e.g., 50%, 60%, 70%, 80%, 90% or even 100% by weight), at least 75% by weight (e.g., 75%, 80%, 90% or even 100% by weight) or even 100% by weight of the 1- 10 phr of at least one liquid plasticizer. In certain embodiments of the first-fourth embodiments, one or more ester plasticizers are used (in one of the foregoing amounts) in combination with oil where the oil is present in an amount of 1 to less than 10 phr, or 3-7 phr. In other embodiments of the first-fourth embodiments, one or more ester plasticizers is used without any oil being present in the tire tread rubber composition ( / .e., 0 phr of oil).P24073W001Cure Package

[0070] As discussed above, according to the first-fourth embodiments disclosed herein, the tire tread rubber composition includes (comprises) a cure package. Although the contents of the cure package may vary according to the first-fourth 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 of the first-fourth 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.

[0071] Examples of suitable types of vulcanizing agents for use in certain embodiments of the first-fourth embodiments, include but are not limited to, sulfur or peroxide-based curing components. Thus, in certain such embodiments, the cure package includes a sulfur-based curative or a peroxide-based curative. In preferred embodiments of the first-fourth embodiments, the vulcanizing agent is a sulfur-based curative; in certain such embodiments the vulcanizing agent consists of (only) a sulfur-based curative. Examples of specific suitable sulfur vulcanizing agents include "rubbermaker's" soluble sulfur; sulfur donating curing agents, such as an amine disulfide, polymeric polysulfide, or sulfur olefin adducts; and insoluble polymeric sulfur. Preferably, the sulfur vulcanizing agent is 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 of the first-fourth embodiments in an amount ranging from 0.1 to 10 phr (e.g., 0.1, 0.5, 1, 2, 3, 4,P24073W0015, 6, 7, 8, 9, or 10 phr), including from 1 to 7.5 phr, including from 1 to 5 phr, and preferably from 1 to 3.5 phr (e.g., 1, 1.5, 2, 2.5, 3, or 3.5 phr).

[0072] 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 of the first-fourth 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), preferably 1 to 6 phr (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5 or 6 phr). Preferably, any vulcanization accelerator used in the rubber compositions of the first-fourth embodiments 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, the rubber compositions of the first-fourth embodiments preferably contain no thiuram accelerators (i.e., 0 Phr).

[0073] Vulcanizing activators are additives used to support vulcanization. Generally vulcanizing activators include both an inorganic and organic component. Zinc oxide is the most widely used inorganic vulcanization activator. Various organic vulcanization activators are commonly used including stearic acid, palmitic acid, lauric acid, and zinc salts of each of the foregoing. Generally, in certain embodiments of the first-fourth 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), preferably 0.5 to 4 phr (e.g., 0.5, 1, 1.5, 2, 2.5, 3 3.5, or 4 phr). In certain embodiments of the first-fourth embodiments, both zinc oxide and stearic acid are used as vulcanizing activators with the total amount utilized falling within one of the foregoing ranges; in certain such embodiments, the only vulcanizing activators used are zinc oxide and stearic acid.P24073W001

[0074] 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 of the first-fourth embodiments the amount of vulcanization inhibitor is 0.01 to 1 phr (e.g., 0.01, 0.015, 0.02, 0.025, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 phr), preferably 0.01 to 0.3 phr (e.g., 0.01, 0.015, 0.02, 0.025, or 0.3 phr). In other embodiments of the first-fourth embodiments, no vulcanization inhibitor (i.e., 0 phr) is present in the tire tread rubber composition.Other Ingredients

[0075] Various other ingredients that may optionally be added to the tire tread rubber compositions of the first-fourth embodiments as disclosed herein include waxes (which in some instances are antioxidants), processing aids (as discussed in more detail below), reinforcing resins, peptizers, and antioxidants / antidegradant. Ingredients which are antidegradants may also be classified as an antiozonant or antioxidant, such as those selected from: N,N'disubstituted-p- phenylenediamines, such as N-l,3-dimethylbutyl-N'phenyl-p-phenylenediamine (6PPD), N,N'- Bis(l,4-dimethylpently)-p-phenylenediamine (77PD), N-phenyl-N-isopropyl-p-phenylened famine (IPPD), and N-phenyl-N'-(l,3-dimethylbutyl)-p-phenylenediamine (HPPD). Other examples of antidegradants include, acetone diphenylamine condensation product, 2,4-Trimethyl-l,2- dihydroquinoline, Octylated Diphenylamine, 2,6-di-t-butyl-4-methyl phenol and certain waxes. In certain other embodiments of the first-fourth embodiments, the tire tread rubber composition may be free or essentially free of antidegradants such as antioxidants or antiozonants.Processing Aid(s)

[0076] In certain embodiments of the first-fourth embodiments, the tire tread rubber composition includes at least one processing aid, preferably in an amount of about 2 to 10 phr or 2 to 10 phr (e.g., 2, 3, 4, 5, 6, 7, 8, 9, or 10 phr), more preferably in an amount of about 4 to about 7 phr (e.g., 4, 4.5, 5, 5.5, 6, 6.5, or 7 phr). One or more than one processing aid may be used. In preferred embodiments of the first-fourth embodiments when at least one processing aid is present (e.g., in an amount as discussed above), a homogenizing agent and a dispersing agent are used as (e.g., comprise) the at least one processing aid. Preferred dispersing agents includeP24073W001 carboxylic acid compounds or metal carboxylate compounds, more preferred within this group of dispersing agents are fatty acid compounds or metal fatty acid compounds (all discussed in more detail below). Preferred homogenizing agents include certain hydrocarbon resins and blends of hydrocarbon resins and other propriety ingredients (discussed in more detail below).

[0077] Dispersing agents are a type of processing aid that aids in the dispersion of fillers (such as carbon black). They may react or interact with the filler and facilitate the filler's dispersion, or they may facilitate filler incorporation and speed the attainment of filler dispersion. In certain embodiments of the first-fourth embodiments where a dispersing agent is used in the rubber composition, it is used in an amount of about 1 to about 6 phr or 1 to 6 phr (e.g., 1, 2, 3, 4, 5, or 6 phr), or an amount of about 2 to about 4 phr (e.g., 2, 3, or 4 phr). As mentioned above, preferred dispersing agents include carboxylic acid compounds, metal carboxylate compounds, and combinations thereof, and more preferred within the foregoing group are fatty acid compounds, metal fatty acid compounds, or a combination thereof. Carboxylic acid compounds suitable for use in the tire tread rubber compositions of the first-fourth embodiments may include a saturated or unsaturated carboxylic acid having 2 to 40 carbon atoms, preferably 5 to 24 carbon atoms, more preferably 8 to 18 carbon atoms. Metal carboxylate compounds suitable for use in the tire tread rubber compositions of the first-fourth embodiments include a metal and the salt of a carboxylic acid (i.e., a carboxylate) with preferred metals being alkali metals (e.g., sodium or potassium), alkaline-earth metals (e.g., magnesium or calcium), transition metals (e.g., iron, nickel, or zinc), or a combination of these metals. Fatty acids are a type of carboxylic acid that were originally considered to be obtained from a natural source but now can be synthetically manufactured. Fatty acids generally have an even number of carbon atoms, preferably 4 to 40 carbon atoms, more preferably 6 to 30 carbon atoms, even more preferably 8 to 24 carbon atoms. Metal fatty acid compounds include a metal and the salt of a fatty acid with the preferred metals being the same as discussed above for metal carboxylate compounds. Exemplary metal fatty acid compounds suitable for use in the tire tread rubber compositions of the first-fourth embodiments include sodium stearate, sodium myristate, sodium laurate, sodium palmitate, sodium oleate, sodium linoleate, calcium stearate, calcium myristate, calcium laurate, calcium palmitate, calcium oleate, zinc stearate, zinc myristate, zinc laurate, zinc palmitate, zinc oleate, zinc linoleate, andP24073W001 combinations thereof. Various process aids suitable for use in the tire tread rubber compositions of the first-fourth embodiments include metal carboxylate compounds, fatty acid compounds, and metal fatty acid compounds are commercially available including, but not limited to, Akrochem Proaid® 9810 (Akrochem, Akron, Ohio); Norac® Calcium Stearate (Sovereign Chemical Co., Akron, Ohio); COAD 10, 20, 23, and LM (Sovereign Chemical Co.); Maxiflow® RS and SP (Rubber Service, Argentina); Struktol® WA48, WB16, W34, WB42, WB212, WB222, EF44A, and JV46F (Struktol Company of America, LLC, Stow, Ohio); and Aktiplast® 8, F2635, M, MS, PP, PP- veg, ST, and T (RheinChemie Additives, Mannheim, Germany).

[0078] As mentioned above, preferred homogenizing agents may vary but suitable ingredients are generally based upon or at least contain a majority by weight of hydrocarbon resins. Generally, a homogenizing resin can be considered to be a resin which improves the processability of a rubber composition by improving the blending of elastomers which may have different properties such as polarity and viscosity, thereby producing a more homogeneous mixture. In certain embodiments of the first-fourth embodiments where a homogenizing resin is used in the rubber composition, it is used in an amount of about 1 to about 5 phr or 1 to 5 phr (e.g., 1, 2, 3, 4, or 5 phr), or an amount of about 2 to about 4 phr (e.g., 2, 3, or 4 phr).

[0079] Suitable homogenizing agents include ingredients with blends of one or more resins such as light or dark hydrocarbon resins, aromatic hydrocarbon resins, or aliphatic-type hydrocarbon resin. Various homogenizing agents suable for use in the tire tread rubber compositions of the first-fourth embodiments are commercially available including, but not limited to, Struktol® 40MS, 60NS, and HP 55 ((Struktol Company of America, LLC, Stow, Ohio); Deotack 1100 and Homogenisator 501 (D.O.G. Deutsche Oelfabrik of Hamburg, Germany); Promix® 400 (HB Chemical); Rhenosin® 260, 145 A or P, and TT 100 (Lanxess Corporation of Pittsburgh, Pennsylvania); and Atsin® R-60 (Atman Co., Ltd of Shanghai City, China).Preparing The Tire Tread Rubber Composition

[0080] The particular steps involved in preparing the tire tread rubber compositions of the first-fourth embodiments 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 certain embodiments of the first-fourth embodiments, theP24073W001 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 non-productive master-batch stage is known to those of skill in the art and generally understood to be a mixing stage (or stages) where no vulcanizing agents or vulcanization accelerators are added. The term final productive mixing stage is also known to those of skill in the art and generally understood to be the mixing stage where the vulcanizing agents and vulcanization accelerators are added into the rubber composition. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition is prepared by a process comprising more than one non-productive master-batch mixing stage.

[0081] In certain embodiments of the first-fourth 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 of the first-fourth embodiments, the primary mixer utilizes intermeshing rotors and in other embodiments the primary mixer utilizes tangential rotors. Preferably, the lower mixer utilizes 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.

[0082] 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-batchP24073W001 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.

[0083] In certain embodiments of the first-fourth embodiments, the tire tread rubber composition is prepared using a process wherein at least one non-productive master batch mixing stage is conducted at a temperature of about 130 °C to about 200 °C. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition is prepared using a final productive mixing stage conducted at a temperature below the vulcanization temperature in order to avoid unwanted pre-cure of the rubber composition. Therefore, the temperature of the productive or final mixing stage generally should not exceed about 120 °C and is typically about 40 °C to about 120 °C, or about 60 °C to about 110 °C and, especially, about 75 °C to about 100 °C. In certain embodiments of the first-fourth 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.Tire Tread Rubber Composition Properties

[0084] The use of the tire tread rubber composition of the first-fourth embodiments disclosed herein, preferably result in a tire having improved or desirable tread properties including, but not limited to wear and / or snow performance, as discussed in detail below.

[0085] The values referred to herein for rolling resistance, snow or ice traction, wet traction, and dry handling refer to tan 5 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 ofP24073W001 rubber (cured for 15 minutes at 170°C) taken out of a tire. A rubber composition's tan 5 at -30 °C is indicative of its snow or ice traction (which may also be referred to as winter performance) when incorporated into a tire tread, tan 5 at 0 °C is indicative of its wet traction (which may also be referred to as wet performance) when incorporated into a tire tread, tan 5 at 30 °C is indicative of its dry handling (which may also be referred to as dry performance) when incorporated into a tire tread and its tan 5 at 60 °C is indicative of its rolling resistance (which may also be referred to as fuel economy) when incorporated into a tire tread (with lower values considered to be more desirable, i.e., having better rolling resistance than a higher value). As those of skill in the art will understand, higher values of tan 6 at 30°C and 0°C indicate better dry and wet performance, respectively, whereas lower values of tan 6 at 60°C and -30°C indicate better rolling resistance and snow performance.

[0086] In certain embodiments of the first-fourth embodiments, the rubber composition has a value for tan 5 at -30 °C of 0.4 to 0.47 (e.g., 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, or 0.47), preferably 0.42 to 0.45 (e.g., 0.42, 0.43, 0.44, or 0.45). A tan 6 at -30 °C within one of the foregoing ranges can be understood as being indicative of a tire (or more specifically, a tire tread) with good snow or ice traction (performance). In certain embodiments of the first-fourth embodiments, the value for tan 6 at -30 °C is combined with at least one of the following: (a) a value for tan 6 at 60 °C of no more than 0.48 times (e.g., 0.48, 0.47, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.4 times or less) the tan 5 at -30 °C value, preferably between 0.42 times and 0.48 times (e.g., 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48 times) the tan 6 at -30 °C value; (b) a value for tan 6 at 30 °C of at least 0.54 times (e.g., 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61 times or higher) the tan 5 at -30 °C value, preferably between 0.54 times and 0.6 times (e.g., 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, or 0.6 times) the tan 5 at -30 °C value; or (c) a value for tan 6 at 0 °C of at least 0.75 times (e.g., 0.75 0.76, 0.77, 0.78, 0.79, 0.8, 0.81 times or higher) the tan 6 at -30 °C value, preferably between 0.75 times and 0.8 times (e.g., 0.75, 0.76, 0.77, 0.78, 0.79, or 0.8 the tan 5 at -30 °C value; in certain such embodiments, the value for tan 6 at -30 °C is combined with each of (a), (b), and (c). In certain embodiments of the first-fourth embodiments, one of the foregoing values for tan 6 at -30 °C (e.g., 0.4 to 0.47 or 0.42 to 0.45, etc.) is combined with (a) a value for tan 5 at 60 °C of between 0.42 times and 0.48 times the tan 5 at -30 °C value, as discussed above.P24073W001In certain embodiments of the first-fourth embodiments, one of the foregoing values for tan 6 at -30 °C (e.g., 0.4 to 0.47 or 0.42 to 0.45, etc.) is combined with (b) a value for tan 5 at 30 °C of between 0.54 times and 0.6 times the tan 6 at -30 °C value, as discussed above. In certain embodiments of the first-fourth embodiments, one of the foregoing values for tan 5 at -30 °C (e.g., 0.4 to 0.47 or 0.42 to 0.45, etc.) is combined with (c) a value for tan 5 at 0 °C of between 0.75 times and 0.8 times the tan 6 at -30 °C value, as discussed above. The foregoing tan 6 values refer to measurements made on a sample taken from a tire where the road -contacting tread of the tire is made from a tire tread rubber composition according to the first or second embodiment disclosed herein. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the abovediscussed ranges in combination with a DIN abrasion according to one of the below-discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the abovediscussed ranges in combination with a Tb x Eb value according to one of the below-discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the abovediscussed ranges in combination with a DIN abrasion according to one of the below-discussed ranges, and a Tb x Eb value according to one of the below-discussed ranges.

[0087] The wear performance of a tire tread rubber composition can be evaluated by various methods. However, the absolute wearvalues provided herein referto DIN abrasion values that can be measured using standard methods including DIN ISO 4649, 2017 edition, or more preferably 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 preferred embodiments of the first-fourth embodiments, the tire tread rubber composition has a DIN abrasion (according to DIN ISO 4649, 2017 edition, more preferably DIN ISO 53516) of no more than 100 mm3(e.g., 100, 99, 98, 97, 96, 95, 94, 93,P24073W00192, 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, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41,40 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, 60,59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 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, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44,43, 42, 41, 40 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, 59, 58, 57, 56, 55, 54, 53,52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 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, 59, 58, 57, 56, 55, 54, 53,52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 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, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48,47, 46, 45, 44, 43, 42, 41, 40 mm3or less), no more than 70 mm3(e.g., 70, 69, 68, 67, 66, 65, 64,63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 mm3or less), no more than 65 mm3(e.g., 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49,48, 47, 46, 45, 44, 43, 42, 41, 40 mm3or less), no more than 60 mm3(e.g., 60, 59, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 mm3or less), no more than 55 mm3(e.g., 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40mm3or less), no more than 50 mm3(e.g., 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40 mm3or less) or 100 to 40 mm3(including ranges within the foregoing), 95 to 40 mm3(including ranges within the foregoing), 90 to 40 mm3(including ranges within the foregoing), 85 to 40 mm3(including ranges within the foregoing), 80 to 40 mm3(including ranges within the foregoing), 75 to 40 mm3(including ranges within the foregoing), 70 to 40 mm3(including ranges within the foregoing), 100 to 50 mm3(including ranges within the foregoing), 95 to 50 mm3(including ranges within the foregoing), 90 to 50 mm3(including ranges within the foregoing), 85 to 50 mm3(including ranges within the foregoing), 80 to 50 mm3(including ranges within the foregoing), 75 to 50 mm3(including ranges within the foregoing), 70 to 50 mm3(including ranges within the foregoing), 100 to 60 mm3(including ranges within the foregoing), 95 to 60 mm3(including ranges within the foregoing), 90 to 60 mm3P24073W001(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). The foregoing DIN abrasion values refer to measurements made on a sample taken from a tire where the road-contacting tread of the tire is made from a tire tread rubber composition according to the first or second embodiment disclosed herein. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a DIN abrasion according to one of the foregoing ranges in combination with tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the above-discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a DIN abrasion according to one of the foregoing ranges in combination with a Tb x Eb value according to one of the below- discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a DIN abrasion according to one of the foregoing ranges in combination with tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the above-discussed ranges, and a Tb x Eb value according to one of the below-discussed ranges.

[0088] In certain embodiments of the first-fourth embodiments, the rubber composition has a hot Tb x Eb (both values determined at 100 °C) of at least 4700 (e.g., 4700, 4750, 4800, 4900, 5000, 5100, 5200, 5300, 5400, or more), or 4700 to 5400 or a sub-range within that range, preferably 4800 to 5400 (e.g., 4800, 4850, 4900, 4950, 5000, 5050, 5100, 5150, 5200, 5250, 5300, 5350, or 5400) or a sub-range within that range, more preferably 4900 to 5200 (e.g., 4900, 4950, 5000, 5050, 5100, 5150, 5200) or a sub-range within that range. Although the units of Tb are MPa (mega Pascals) and the units of Eb at % (elongation), the value of Tb x Eb is reported herein as unitless. The hot Tb x Eb is calculated by multiplying the hot Tb with the hot Eb value and refers to measurements made at 100 ° C. The foregoing hot Tb x Eb values refer to measurements of Tb and Eb each made at 100 °C. Eb can be measured following the guidelines, but not restrictedP24073W001 to, the standard procedure described in ASTM D-412, with dumbbell-shaped samples having a cross-section dimension of 4 mm in width and 1.9 mm in thickness at the center. During measurement, specimens may be strained at a constant rate (20% per second) and the resulting force recorded as a function of extension (strain). Generally, a hot Eb value for a given tread rubber composition will be lower ( / .e., less than) the room temperature Eb for that tread rubber composition. Tb can be measured following the guidelines, but not restricted to, the standard procedure described in ASTM D-412, with dumbbell-shaped samples having a cross-section dimension of 4 mm in width and 1.9 mm in thickness at the center. During measurement, specimens may be strained at a constant rate (20% per second) and the resulting force recorded as a function of extension (strain). The foregoing Tb x Eb values (and Tb and Eb) values refer to measurements made on a sample taken from a tire where the road-contacting tread of the tire is made from a tire tread rubber composition according to the first or second embodiment disclosed herein. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a Tb x Eb value according to one of the foregoing ranges in combination with a DIN abrasion value according to one of the above-discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a Tb x Eb value according to one of the foregoing ranges in combination with tan 5 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the above-discussed ranges. In certain embodiments of the first-fourth embodiments, the tire tread rubber composition has a Tb x Eb value according to one of the foregoing ranges in combination with a DIN abrasion value according to one of the abovediscussed ranges, and tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C according to one of the abovediscussed ranges.Tires and Tire Tread Types

[0089] It is specifically contemplated that the tire tread rubber compositions according to the first and second embodiments, as disclosed herein, will be utilized in a tire tread. Thus, also disclosed herein is a tire tread comprising (made from) the tire tread rubber composition according to the first or second embodiments, as discussed herein. As well, such a tire tread can be utilized in a tire (along with other components). Thus, also disclosed herein (i.e., as the third and fourth embodiments) is a tire having a tread comprising (made from) the tire tread rubberP24073W001 composition according to the first or second embodiments, as discussed herein. The particular type of tire may vary. In certain embodiments, the tire ( / .e., according to the third or fourth embodiments disclosed herein) which incorporates a tread made from the tire tread rubber composition according to the first or second embodiments is a passenger vehicle tire. In other certain embodiments, the tire ( / .e., according to the third or fourth embodiments disclosed herein) which incorporates a tread made from the tire tread rubber composition according to the first or second embodiments is a light truck tire. In certain embodiments of the third and fourth embodiments, the tire is a passenger vehicle tire which incorporates a tread made from the tire tread rubber composition according to the first or second embodiments; in certain such embodiments, the tire is marked with an P-metric designation. In certain other embodiments of the third and fourth embodiments, the tire is a light truck tire which incorporates a tread made from the tire tread rubber composition according to the first or second embodiments; in certain such embodiments, the tire is marked with an LT designation.EXAMPLES

[0090] The following examples illustrate specific and exemplary embodiments and / or features of the embodiments of the present disclosure. The examples are provided solely for the purposes of illustration and should not be construed as limitations of the present disclosure. Numerous variations over these specific examples are possible without departing from the spirit and scope of the presently disclosed embodiments. It should specifically be understood that tire tread rubber compositions according to the present disclosure can be made using polybutadiene(s) (ii) and natural rubber(s) and / or polyisoprene(s) (i) according to the description provided herein for the first-fourth embodiments, different reinforcing silica filler, different carbon black, different hydrocarbon plasticizer resin, and different liquid plasticizing agents, generally in connection with the teachings provided herein and as fully disclosed in the preceding paragraphs. It should also be understood that the foregoing ingredients can differ in relative amount, composition, or both from those used in the examples ( / .e., as fully as disclosed in the preceding paragraphs).

[0091] As provided in Table 1, tread rubber compositions can be / were prepared using ingredients in accordance with the amounts and types disclosed in the preceding paragraphs toP24073W001 formulate an inventive composition listed as Example 1. Comparative tread rubber compositions can / were also be prepared using varying types and / or amounts of certain ingredients and are listed in Table 1 as Control 1, Control 2, and Control 3. Notably, each of Control 1, 2 and 3 uses at least one ingredient outside of the amounts and / or types listed for the rubber composition of Example 1. More specifically, Control 1 contains natural rubber and non-functionalized polybutadiene. Control 2 contains no natural rubber but contains functionalized polybutadiene and non-functionalized styrene-butadiene rubber. Control 3 contains natural rubber, functionalized styrene-butadiene rubber, and no polybutadiene. As can be seen in Table 1, only the inventive example (Example 1) provides a tire tread rubber composition which has tan 6 values at -30 °C, 60 °C, 30 °C, and 0 °C within the ranges disclosed herein. Additionally, the inventive example (Example 1) provides a tire tread rubber composition which has a hot Tb x Eb value within the ranges disclosed herein whereas at least certain of the Control examples do not.1High cis-polybutadiene having a cis-l,4-bond content of at least 95% and a Tg in the range of -105 to -108 °C.2High cis-polybutadiene having a silica-reactive functional group, a cis-l,4-bond content of at least 95%, and a Tg in the range of -105 to -108 °C.3SBR-1 is a functionalized copolymer having a Tg of less than -40 °C. .4SBR-2 is a non-functionalized copolymer having a Tg of greater than -40 °C, a styrene content of more than 25%, and a vinyl bond content above the range of 30 to 40%. This SBR is also oil-extended in an amount of 37.5 parts per 100 parts of rubber. The amount listed in Table 1 is the amount of rubber contributed by the oil-extended SBR and does not include the oil contribution of SBR-1.P24073W001

[0092] As set forth in Table 1, the rubber composition of Example 1 (which is inventive) has tan 5 values and Tb x Eb (at 100 °C) values within the ranges set forth herein showing that use of ingredients according to the first-fourth embodiments set forth herein produces a rubber composition or tire tread having tan 6 values and Tb x Eb values within the ranges set forth above. Conversely, in control Examples 1-3, ingredients which differ from the ingredients of Example 1 (and which do not all correspond to the ingredients according to the first-fourth embodiments set forth herein) are used. Control Examples 1-3 fail to have one or more tan 5 values and / or Tb5Reinforcing silica filler having a BET surface area in the range of 150 to 300 m2 / g.6Plant-sourced oil, petroleum-sourced oil, or a combination thereof.7Aromatic resin having a Tg in the range of 30 to 50 °C.P24073W001 x Eb (at 100 °C) values within the ranges set forth herein. As denoted by the use of * in Table 1, the Tb x Eb for control example 3 is based upon a comparison of slab Tb and Eb values for control 3 compared to slab Tb and Eb values for Example 1 (since tire samples were not available for control 3).

[0093] This application discloses several numerical range limitations that support any range within the disclosed numerical ranges, even though a precise range limitation is not stated verbatim in the specification, because the embodiments of the compositions and methods disclosed herein could be practiced throughout the disclosed numerical ranges. With respect to the use of substantially any plural or singular terms herein, those having skill in the art can translate from the plural to the singular or from the singular to the plural as is appropriate to the context or application. The various singular or plural permutations may be expressly set forth herein for sake of clarity.

[0094] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as "open" terms. For example, the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to." It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recitedP24073W001 number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., " a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

[0095] All references, including but not limited to patents, patent applications, and nonpatent literature are hereby incorporated by reference herein in their entirety.

[0096] While various aspects and embodiments of the compositions and methods have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the claims.

Claims

P24073W001What is claimed is:

1. A tire tread rubber composition comprising: a. 100 parts of an elastomer component comprising i. 40-60 parts, preferably 45 to 55 parts of natural rubber, polyisoprene, or a combination thereof, and ii. 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, and a silica-reactive functional group, and wherein the elastomer component includes no more than 10 parts of styrene-butadiene rubber, preferably no more than 5 parts of styrenebutadiene rubber, more preferably 0 parts of styrene-butadiene rubber; b. 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferably about 150 to about 300 m2 / g; c. 30-60 phr, preferably 40-55 phr of carbon black; d. 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C; e. 1-10 phr, preferably 3-7 phr, of at least one liquid plasticizer, which preferably consists of at least one oil; and f. a cure package, wherein the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.

2. The tire tread rubber composition of claim 1, wherein the total amount of the natural rubber, polyisoprene, or a combination thereof of (a )( i) and the polybutadiene rubber of (a )(ii) is at least 90 parts, preferably at least 95 parts, more preferably 100 parts.

3. The tire tread rubber composition of claim 1 or claim 2, wherein the polybutadiene rubber of (a)(ii) has a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole, as determined by GPC using a polystyrene standard.P24073W0014. The tire tread rubber composition of any one of claims 1-3, wherein the polybutadiene of (ii) has less than 3% by weight syndiotactic 1,2-polybutadiene, preferably 0%.

5. The tire tread rubber composition of any one of claims 1-4, wherein the polybutadiene of (ii) has a silica-reactive functional group resulting from a functional compound having the following formula (II):wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4-epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms , a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof.

6. The tire tread rubber composition of claim 5, wherein the monovalent epoxy group A1is selected from glycidoxy groups.

7. The tire tread rubber composition of claim 5, wherein the monovalent epoxy group A1is selected from 3,4-epoxycyclohexyl groups.P24073W0018. The tire tread rubber composition of claim 5, wherein the monovalent epoxy group is selected from a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc.

9. The tire tread rubber composition of any one of claims 1-8, wherein (b) and (c) are present in a total amount of 70 to 90 phr.

10. The tire tread rubber composition of any one of claims 1-9, wherein the at least one hydrocarbon resin of (d) is an aliphatic hydrocarbon resin.

11. The tire tread rubber composition of any one of claims 1-10, wherein the at least one hydrocarbon resin of (d) includes less than 5 phr of terpene resin, preferably 0 phr of terpene resin.

12. The tire tread rubber composition of any one of claims 1-11, wherein the at least one liquid plasticizer of (e) includes plant oil.

13. A tire tread rubber composition comprising: a. 100 parts of an elastomer component comprising i. 40-60 parts, preferably 45-55 parts of natural rubber, polyisoprene, or a combination thereof, and ii. 60-40 parts, preferably 55-45 parts, of polybutadiene rubber having a cis bond content of at least 95%, a Tg of less than -101 °C, preferably -101 to -110 °C, a Mw of about 450,000 to about 700,000 grams / mole, preferably about 500,000 to about 650,000 grams / mole (as determined by GPC using a polystyrene standard), and a silica-reactive functional group resulting from a functional compound having the following formula (II):P24073W001 wherein A1represents a monovalent epoxy group, preferably selected from glycidoxy groups, 3,4-epoxycyclohexyl groups, or a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc; Rcrepresents a single bond or a divalent hydrocarbon group having from 1 to 20 carbon atoms; Rdrepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms , a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms or a reactive group; Rerepresents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; b is an integer of 0 to 2; when more than one Rdor OReare present, each Rdand / or ORemay be the same as or different from each other; and an active proton is not contained in a molecule) and / or a partial condensation product thereof, wherein the total amount of the natural rubber, polyisoprene, or a combination thereof of (a)(i) and the polybutadiene rubber of (a)(ii) is at least 90 parts, preferably at least 95 parts, more preferably 100 parts; b. 25-50 phr, preferably 30-40 phr of at least one reinforcing silica filler having a surface area of about 100 to about 300 m2 / g, preferably about 150 to about 300 m2 / g; c. 30-60 phr, preferably 40-55 phr of carbon black; d. 10-25 phr, preferably 15-20 phr, of at least one hydrocarbon plasticizer resin having a Tg of about 40 to about 60 °C, wherein the at least one hydrocarbon plasticizer resin is an aliphatic hydrocarbon resin; e. 1-10 phr, preferably 3-7 phr, of at least one oil plasticizer, wherein the at least one oil plasticizer preferably includes plant oil; and f. a cure package, and wherein the total amount of (b) and (c) is 70-90 phr, and the total amount of (d) and (e) is 15-30 phr, preferably 18-27 phr.P24073W00114. The tire tread rubber composition of claim 13, wherein the monovalent epoxy group A1is selected from glycidoxy groups.

15. The tire tread rubber composition of claim 13, wherein the monovalent epoxy group is selected from a glycidyl group having 3-8, preferably 3-6, carbons overall, with the 2 end carbons being within the epoxy ring and the other end of the carbon chain bonded to Rc.

16. The tire tread rubber composition of any one of claims 1-15, further comprising at least one silica coupling agent, preferably in an amount of 0.1 to 10 phr, more preferably 1 to 10 phr, even more preferably 2 to 7 phr.

17. The tire tread rubber composition of any one of claims 1-16, wherein the rubber composition has a value for tan 6 at -30 °C of 0.4 to 0.47, preferably 0.42 to 0.45 and meets at least one of the following, preferably each of the following: a. has a value for tan 5 at 60 °C of no more than 0.48 times the tan 5 at -30 °C value, preferably between 0.42 times and 0.48 times the tan 6 at -30 °C value; b. has a value for tan 6 at 30 °C of at least 0.54 times the tan 6 at -30 °C value, preferably between 0.54 times and 0.6 times the tan 5 at -30 °C value; or c. has a value for tan 6 at 0 °C of at least 0.75 times the tan 6 at -30 °C value, preferably between 0.75 times and 0.8 times the tan 5 at -30 °C value.

18. The tire tread rubber composition according to any one of claims 1-17, wherein the rubber composition has tear strength as evidenced by a Tb x Eb value (with Tb and Eb both measured at 100 °C), of at least 4700, preferably 4800 to 5400, more preferably 4900 to 5200.

19. The tire tread rubber composition of any one of claims 1-18, wherein the rubber composition has a DIN abrasion of no more than 90 mm3, preferably no more than 85 mm3, and more preferably no more than 80 mm3.

20. A tire having a tread comprising the tire tread rubber composition of any one of claims 1-19.P24073W00121. The tire of claim 20, wherein the tire is a passenger vehicle tire, preferably including a P- metric designation.

22. The tire of claim 20, wherein the tire is a light truck tire, preferably including a LT designation.

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