Patent Description:
The tire industry has been developing tires particularly suitable for different weather conditions. While ultra-high performance (UHP) tires or ultra-ultra-high performance (UUHP) tires are often designed to have superior dry performance, an improved wet performance is also desirable for many customers to improve handling and safety under wet weather conditions. At the same time, such tires shall ideally have no or at least only limited tradeoffs in dry handling as well as in rolling resistance and/or tread wear so as to provide limited fuel or energy consumption and a sustainable product.

<CIT> and <CIT> describe a rubber composition in accordance with the preamble of claim <NUM>.

The invention relates to a rubber composition in accordance with claim <NUM> and to a tire in accordance with claim <NUM>.

One object of the present invention is to provide a rubber composition for a tire providing good dry handling performance and improved wet handling performance.

Another object of the present invention is to provide a rubber composition for a tire providing an advanced balance between dry handling performance, wet handling performance and rolling resistance, and preferably also tread wear.

Yet another object of the present invention may be to provide a UHP, UUHP and/or race tire having an advanced wet handling performance, preferably with at least one of limited treadwear, good dry handling performance and/or low rolling resistance.

Thus, in a first preferred aspect, the present invention is directed to a rubber composition comprising <NUM> phr to <NUM> phr of a styrene butadiene rubber (which is preferably solution polymerized); <NUM> phr to <NUM> phr of at least one (further) diene based rubber; <NUM> phr to <NUM> phr of filler comprising: i) <NUM> phr to <NUM> phr of silica, ii) <NUM> phr to <NUM> phr of carbon black and iii) <NUM> phr to <NUM> phr of a, preferably inorganic, metal hydroxide. Moreover, the rubber composition comprises <NUM> phr to <NUM> phr of plasticizer comprising a hydrocarbon resin having a softening point within a range of <NUM> to <NUM>.

In particular, such a rubber composition including a blend of substantial amounts of carbon black and silica in combination with the inorganic metal hydroxide has turned out to provide an advanced balance between dry handling performance, wet handling performance and abrasion.

In a preferred embodiment, the filler comprises one or more of: from <NUM> to <NUM> phr, of the silica, and from <NUM> phr to <NUM> phr, preferably from <NUM> to <NUM> phr, or even more preferably from <NUM> to <NUM> phr, of the carbon black.

In another preferred embodiment, the filler comprises at least <NUM> phr more silica than carbon black and/or at most <NUM> phr more silica than carbon black, preferably at most <NUM> phr more silica than carbon black. Thus, while the composition comprises substantial amounts of carbon black, a higher amount of silica than carbon black is preferred herein.

In still another preferred embodiment, the inorganic metal hydroxide is aluminum hydroxide. Such a material has turned out to be the most preferred inorganic metal hydroxide.

In yet another preferred embodiment the aluminum hydroxide has one or more of: i) a BET surface area within a range of <NUM><NUM>/g to <NUM><NUM>/g, preferably from <NUM><NUM>/g to <NUM><NUM>/g, or even more preferably <NUM><NUM>/g; and ii) a d50 value within a range of <NUM> to <NUM>, preferably <NUM>, or even more preferably <NUM>.

Aluminum hydroxide particle diameters are determined with a Zetasizer™ Nano S from Malvern using dynamic light scattering, based on ISO <NUM> or equivalent. The BET surface area of aluminum hydroxide particles is determined in accordance with ISO <NUM> or equivalent.

In still another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr, preferably from <NUM> phr to <NUM> phr, or even more preferably from <NUM> phr to <NUM> phr of the filler. Higher filler amounts would impact rolling resistance, whereas lower filler values would impact stiffness and handling properties.

In still another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of oil, preferably from <NUM> phr to <NUM> phr of oil.

In yet another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of the resin, or preferably from <NUM> phr to <NUM> phr of the resin. Preferably the resin is a traction resin.

In still another preferred embodiment, the resin to oil ratio is between <NUM>:<NUM> to <NUM>:<NUM>, preferably <NUM>:<NUM> to <NUM>:<NUM>.

In still another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of the resin and/or from <NUM> phr to <NUM> phr of oil.

In still another preferred embodiment, the hydrocarbon resin is selected from one or more of coumarone-indene resin, petroleum hydrocarbon resin, terpene resin, styrene/alphamethylstyrene resin, terpene phenol resin, and optionally copolymers and/or mixtures thereof. In yet another embodiment, the resin may be hydrogenated and/or modified, or in other words functionalized.

In still another preferred embodiment, the resin has a weight average molecular weight Mw within a range of <NUM>/mol to <NUM>/mol, preferably <NUM>/mol to <NUM>/mol.

Mw is determined herein using gel permeation chromatography (GPC) according to ASTM <NUM>-<NUM> using polystyrene calibration standards.

In still another preferred embodiment, the resin is a DCPD resin, which is optionally hydrogenated and/or modified with an aromatic monomer, and wherein the resin has optionally a weight average molecular weight within a range of <NUM>/ mol to <NUM>/mol. In particular, such a resin has turned out to be advantageous for wet traction and rolling resistance trade off.

In still another preferred embodiment, the resin has a glass transition temperature within a range of <NUM> to <NUM>. Thus, a resin with a relatively high Tg, or softening point respectively, is preferred.

In still another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of the plasticizer. Plasticizers can for example include liquid plasticizers such as oils or liquid polymers, e. , liquid diene based polymers. Liquid plasticizer shall mean herein a plasticizer that is in a liquid state at a temperature of <NUM>.

In still another preferred embodiment, the composition comprises <NUM>,<NUM>-bis(N,N-dibenzylthiocarbamoyldithio)hexane / BDBzTH, or a derivative thereof, preferably within a range of <NUM> phr to <NUM> phr.

In yet another preferred embodiment, the composition comprises one or more reversion inhibitors such as <NUM>,<NUM> Bis(citraconimidamethyl)benzene, preferably within a range of <NUM> phr to <NUM> phr.

In still another preferred embodiment, the rubber composition further comprises from <NUM> phr to <NUM> phr of one or more gum rosins (optionally, including at least partially dimerized gum rosins). Alternatively, the term gum rosin may also be replaced by rosin herein. One effect of those materials is an improved dry traction.

In still another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of at least one silane, comprising or consisting of <NUM>-(octanoylthio)-<NUM>-propyltriethoxysilane. One effect of this material is a reduced rolling resistance. Preferably, the rubber composition comprises from <NUM> phr to <NUM> phr or from <NUM> phr to <NUM> phr of this silane.

In still another preferred embodiment, the silica has a BET surface area of at least <NUM><NUM>/g, preferably of at least <NUM><NUM>/g, or even more preferably of at least <NUM><NUM>/g.

In yet another preferred embodiment, the carbon black has an iodine absorption number of at least <NUM>/kg, preferably at least <NUM>/kg or even at least <NUM>/kg and optionally at most <NUM>/kg, preferably at most <NUM>/kg.

In still another preferred embodiment, the rubber composition comprises the diene based rubber, which is chosen from natural rubber, synthetic polyisoprene, polybutadiene rubber and (another) styrene butadiene rubber.

In still another preferred embodiment, the styrene butadiene rubber has a glass transition temperature within a range of -<NUM> (preferably -<NUM>) to -<NUM> (preferably -<NUM>), wherein the further diene based rubber comprised in the rubber composition has a glass transition temperature within a range of -<NUM> (preferably -<NUM>) to -<NUM>.

In still another preferred embodiment, the styrene butadiene rubber is a solution polymerized styrene butadiene rubber and/or has a glass transition temperature within a range of -<NUM> (preferably -<NUM>) to -<NUM> and the rubber composition comprises from <NUM> phr to <NUM> phr of the solution polymerized styrene butadiene rubber, and wherein the rubber composition optionally comprises from <NUM> phr to <NUM> phr of the at least one (further) diene based rubber, preferably selected from one or more of natural rubber, synthetic polyisoprene, polybutadiene rubber and another styrene butadiene rubber.

In still another preferred embodiment, the further diene based rubber comprised in the rubber composition comprises a polybutadiene rubber, preferably having a glass transition temperature within a range of -<NUM> to -<NUM>.

In still another preferred embodiment, the styrene butadiene rubber, which is the predominant polymer in the rubber composition, has a bound styrene content of at least <NUM>%, preferably at least <NUM>% and at most <NUM>%; and/or a vinyl content of less than <NUM>%, preferably less than <NUM>% but more than <NUM>%.

In yet another preferred embodiment, the rubber composition comprises from <NUM> phr to <NUM> phr of a vegetable oil having a glass transition temperature of less than -<NUM> (and preferably more than -<NUM>); and/or from <NUM> phr to <NUM> phr of a mineral oil, such as TDAE oil. Amongst others, the low glass transition temperature of the vegetable oil helps to adjust the compound glass transition temperature and provides the compound also with more sustainable material.

In an embodiment, the rubber composition may include at least one and/or one additional diene-based rubber. Representative synthetic polymers may be the homopolymerization products of butadiene and its homologues and derivatives, for example, methyl butadiene, dimethylbutadiene and pentadiene as well as copolymers such as those formed from butadiene or its homologues or derivatives with other unsaturated monomers.

Among the latter may be acetylenes, for example, vinyl acetylene; olefins, for example, isobutylene, which copolymerizes with isoprene to form butyl rubber; vinyl compounds, for example, acrylic acid, acrylonitrile (which polymerize with butadiene to form NBR), methacrylic acid and styrene, the latter compound polymerizing with butadiene to form SBR, as well as vinyl esters and various unsaturated aldehydes, ketones and ethers, e. acrolein, methyl isopropenyl ketone and vinylethyl ether. Specific examples of synthetic rubbers include neoprene (polychloroprene), polybutadiene (including cis <NUM>,<NUM>-polybutadiene), polyisoprene (including cis <NUM>,<NUM>-polyisoprene), butyl rubber, halobutyl rubber such as chlorobutyl rubber or bromobutyl rubber, styrene/isoprene/butadiene rubber, copolymers of <NUM>,<NUM>-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylate, as well as ethylene/propylene terpolymers, also known as ethylene/propylene/diene monomer (EPDM), and in particular, ethylene/propylene/dicyclopentadiene terpolymers. Additional examples of rubbers which may be used include alkoxy-silyl end functionalized solution polymerized polymers (SBR, PBR, IBR and SIBR), silicon-coupled and tin-coupled star-branched polymers. Preferred rubber or elastomers may be in general natural rubber, synthetic polyisoprene, polybutadiene and SBR including SSBR.

In another embodiment, the composition may comprise at least two diene-based rubbers. For example, a combination of two or more rubbers is preferred such as cis <NUM>,<NUM>-polyisoprene rubber (natural or synthetic, although natural is preferred), <NUM>,<NUM>-polyisoprene rubber, styrene/isoprene/butadiene rubber, emulsion and solution polymerization derived styrene/butadiene rubbers, cis <NUM>,<NUM>-polybutadiene rubbers, and emulsion polymerization prepared butadiene/acrylonitrile copolymers.

In another embodiment, an emulsion polymerization derived styrene/butadiene (ESBR) might be used having a styrene content of <NUM> to <NUM> percent bound styrene or, for some applications, an ESBR having a medium to relatively high bound styrene content, namely, a bound styrene content of <NUM> to <NUM> percent. In many cases the ESBR will have a bound styrene content which is within the range of <NUM> percent to <NUM> percent. By emulsion polymerization prepared ESBR, it may be meant that styrene and <NUM>,<NUM>-butadiene are copolymerized as an aqueous emulsion. Such are well known to those skilled in such art. The bound styrene content can vary, for example, from <NUM> to <NUM> percent. In one aspect, the ESBR may also contain acrylonitrile to form a terpolymer rubber, as ESBAR, in amounts, for example, of <NUM> to <NUM> weight percent bound acrylonitrile in the terpolymer. Emulsion polymerization prepared styrene/butadiene/acrylonitrile copolymer rubbers containing <NUM> to <NUM> weight percent bound acrylonitrile in the copolymer may also be contemplated as diene-based rubbers.

In another embodiment, solution polymerization prepared SBR (SSBR) may be used. Such an SSBR may for instance have a bound styrene content in a range of <NUM> to <NUM> percent, preferably <NUM> to <NUM>, percent, and most preferably <NUM> to <NUM> percent. The SSBR can be conveniently prepared, for example, by anionic polymerization in an inert organic solvent. More specifically, the SSBR can be synthesized by copolymerizing styrene and <NUM>,<NUM>-butadiene monomer in a hydrocarbon solvent utilizing an organo lithium compound as the initiator. In still another embodiment, the solution styrene butadiene rubber is a tin-coupled polymer. In still another embodiment, the SSBR is functionalized for improved compatibility with silica. In addition, or alternatively, the SSBR is thio-functionalized. This helps to improve stiffness of the compound and/or its hysteresis behavior. Thus, for instance, the SSBR may be a thio-functionalized, tin-coupled solution polymerized copolymer of butadiene and styrene. Other functionalizations include siloxy, silanol, carboxy, amino, amino silane, amino siloxane and other functionalizations known in the state of the art.

In one embodiment, a synthetic or natural polyisoprene rubber may be used. Synthetic cis-<NUM>,<NUM>-polyisoprene and natural rubber are as such well known to those having skill in the rubber art. In particular, the cis <NUM>,<NUM>-microstructure content may be at least <NUM>% and is typically at least <NUM>% or even higher.

In one embodiment, cis-<NUM>,<NUM>-polybutadiene rubber (BR or PBD) is used. Suitable polybutadiene rubbers may be prepared, for example, by organic solution polymerization of <NUM>,<NUM>-butadiene. The BR is preferably characterized by having at least a <NUM> percent cis-<NUM>,<NUM>-microstructure content ("high cis" content) and a glass transition temperature (Tg) in a range of from -<NUM> to -<NUM>.

Suitable polybutadiene rubbers are available commercially, such as Budene® <NUM>, Budene® <NUM>, Budene® <NUM>, or Budene® <NUM> from The Goodyear Tire & Rubber Company. These high cis-<NUM>,<NUM>-polybutadiene rubbers can for instance be synthesized utilizing nickel catalyst systems which include a mixture of (<NUM>) an organonickel compound, (<NUM>) an organoaluminum compound, and (<NUM>) a fluorine containing compound as described in <CIT> and <CIT>.

A glass transition temperature, or Tg, of an elastomer represents the glass transition temperature of the respective elastomer in its uncured state. A glass transition temperature of an elastomer composition represents the glass transition temperature of the elastomer composition in its cured state. Tg is determined as a peak midpoint by a differential scanning calorimeter (DSC) at a temperature rate of increase of <NUM>° C per minute, according to ASTM D3418 or equivalent.

The term "phr" as used herein, and according to conventional practice, refers to "parts by weight of a respective material per <NUM> parts by weight of rubber, or elastomer". In general, using this convention, a rubber composition is comprised of <NUM> parts by weight of rubber/elastomer. The claimed composition may comprise other rubbers/elastomers than explicitly mentioned in the claims, provided that the phr value of the claimed rubbers/elastomers is in accordance with claimed phr ranges and the amount of all rubbers/elastomers in the composition results in total in <NUM> parts of rubber. In an example, the composition may further comprise from <NUM> phr to <NUM> phr, optionally from <NUM> phr to <NUM> phr, of one or more additional diene-based rubbers, such as SBR, SSBR, ESBR, PBD/BR, NR and/or synthetic polyisoprene. In another example, the composition may include less than <NUM> phr, preferably less than <NUM>, phr of an additional diene-based rubber or be also essentially free of such an additional diene-based rubber. The terms "compound" and "composition" and "formulation" may be used herein interchangeably, unless indicated otherwise. The terms "rubber" and "elastomer" may also be used herein interchangeably.

Molecular weights of elastomers/rubbers, such as Mn (number average molecular weight), Mw (weight average molecular weight) and Mz (z average molecular weight), are determined herein using gel permeation chromatography (GPC) according to ASTM <NUM>-<NUM> using polystyrene calibration standards, or equivalent.

A Tg for resins is determined as a peak midpoint by a differential scanning calorimeter (DSC) at a temperature rate of increase of <NUM>° C per minute, according to ASTM D6604 or equivalent.

Preferably, the resin has a softening point above <NUM>° C as determined by ASTM E28 which might sometimes be referred to as a ring and ball softening point.

A coumarone-indene resin preferably contains coumarone and indene as monomer components making up the resin skeleton (main chain). Monomer ingredients other than coumarone and indene which may be incorporated into the skeleton are, for example, methyl coumarone, styrene, alphamethylstyrene, methylindene, vinyltoluene, dicyclopentadiene, cyclopentadiene, and diolefins such as isoprene and piperlyene. Coumarone-indene resins have preferably softening points ranging from <NUM>° C to <NUM>° C (as measured by the ball-and-ring method). Even more preferably, the softening point ranges from <NUM>° C to <NUM>° C.

Suitable petroleum resins include both aromatic and nonaromatic types. Several types of petroleum resins are available. Some resins have a low degree of unsaturation and high aromatic content, whereas some are highly unsaturated and yet some contain no aromatic structure at all. Differences in the resins are largely due to the olefins in the feedstock from which the resins are derived. Conventional derivatives in such resins include any C5 species (olefins and diolefines containing an average of five carbon atoms) such as cyclopentadiene, dicyclopentadiene, diolefins such as isoprene and piperylene, and any C9 species (olefins and diolefins containing an average of <NUM> carbon atoms) such as vinyltoluene, alphamethylstyrene and indene. Such resins are made by any mixture formed from C5 and C9 species mentioned above and are known as C5/C9 copolymer resins.

In a preferred embodiment, C5 resins are aliphatic resins made from one or more of the following monomers: <NUM>,<NUM>-pentadiene (e.g., cis or trans), <NUM>-methyl-<NUM>-butene, cyclopentene, cyclopentadiene, and dicyclopentadiene.

In another preferred embodiment, a C9 resin is a resin made from one or more aromatic monomers, preferably chosen from the group of indene, methylindene, vinyl toluene, styrene and methylstyrene (such as alpha-methylstyrene).

In still another preferred embodiment, a C9 modified resin is a resin (such as a C5 resin) which has been modified or functionalized with one or more aromatic monomers, preferably chosen from the group of indene, methylindene, vinyl toluene, styrene and methylstyrene (such as alpha methylstyrene).

Terpene resins are preferably comprised of polymers of at least one of limonene, alpha pinene, beta pinene and delta-<NUM>-carene. Such resins are available with softening points ranging from <NUM> to <NUM>° C.

Terpene-phenol resins may be derived by copolymerization of phenolic monomers with terpenes such as limonenes, pinenes and delta-<NUM>-carene.

A styrene/alphamethylstyrene resin is considered herein to be a (preferably relatively short chain) copolymer of styrene and alphamethylstyrene with a styrene/alphamethylstyrene molar ratio in a range of from <NUM> to <NUM>. In one aspect, such a resin can be suitably prepared, for example, by cationic copolymerization of styrene and alphamethylstyrene in a hydrocarbon solvent. Thus, the contemplated styrene/alphamethylstyrene resin can be characterized, for example, by its chemical structure, namely its styrene and alphamethylstyrene contents and by its glass transition temperature, molecular weight and molecular weight distribution.

In one embodiment, said resin is partially or fully hydrogenated.

In a preferred embodiment, the rubber composition comprises oil, such as processing oil. Oil may be included in the rubber composition as extending oil typically used to extend elastomers. Oil may also be included in the rubber composition by addition of the oil directly during rubber compounding. Oil used may include both extending oil present in the elastomers, and (process) oil added during compounding. Suitable oils may include various oils as are known in the art, including aromatic, paraffinic, naphthenic, vegetable oils, and low PCA oils, such as MES, TDAE, SRAE and heavy naphthenic oils. Suitable low PCA oils may include those having a polycyclic aromatic content of less than <NUM> percent by weight as determined by the IP346 method. Procedures for the IP346 method may be found in <NPL>. Some representative examples of vegetable oils that can be used include soybean oil, sunflower oil, canola (rapeseed) oil, corn oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, and safflower oil. Soybean oil and corn oil are typically preferred vegetable oils.

Glass transition temperatures Tg for oils are determined as a peak midpoint by a differential scanning calorimeter (DSC) at a temperature rate of increase of <NUM> per minute, according to ASTM E1356, or equivalent.

In a preferred embodiment, the rubber composition comprises silica. Silica may be for instance pyrogenic/fumed or precipitated silica. In preferred embodiments, precipitated silica is used. Silicas might be characterized, for example, by having a BET surface area, as measured using nitrogen gas. In one embodiment, the BET surface area may be in the range of <NUM> to <NUM> square meters per gram. In another embodiment, the BET surface area may be in a range of <NUM> to <NUM> square meters per gram. The BET surface area is determined according to ASTM D6556 or equivalent and is described in the <NPL>). Silica may also be characterized by having a dibutylphthalate (DBP) absorption value in a range of <NUM><NUM>/<NUM> to <NUM><NUM>/<NUM>, alternatively <NUM><NUM>/<NUM> to <NUM><NUM>/<NUM> which is determined according to ASTM D <NUM> or equivalent. Silica may have an average ultimate particle size, for example, in the range of <NUM> to <NUM> micron as determined by the electron microscope, although the silica particles may be even smaller, or possibly larger, in size. Various commercially available silicas may be used, such as silicas commercially available from PPG Industries under the Hi-Sil trademark with designations <NUM>, <NUM>, and EZ160G; silicas available from Solvay, with, for example, designations of Z1165MP and Premium200MP; and silicas available from Evonik AG with, for example, designations VN2 and Ultrasil 6000GR, 9100GR.

In still another preferred embodiment, the rubber composition may comprise pre-silanized and/or hydrophobated silica which may for instance have a CTAB adsorption surface area of between <NUM><NUM>/g and <NUM><NUM>/g, optionally between <NUM><NUM>/g and <NUM><NUM>/g and/or between <NUM><NUM>/g and <NUM><NUM>/g, or even between <NUM><NUM>/g and <NUM><NUM>/g.

The CTAB (cetyl trimethyl ammonium bromide) method for determination of the silica surface area (ASTM D6845) is known to the person skilled in the art.

Some examples of pre-treated silicas (i.e., silicas that have been pre-surface treated with a silane) which are suitable for use in the practice of this invention include Ciptane® <NUM> LD and Ciptane® LP (PPG Industries) silicas that have been pre-treated with a mercaptosilane, and Coupsil® <NUM> (Degussa) that is the product of the reaction between organosilane Bis(triethoxysilylpropyl) polysulfide (Si69) and Ultrasil® VN3 silica, and Coupsil® <NUM>, Agilon® <NUM> silica from PPG Industries, Agilon® <NUM> silica from PPG Industries, and Agilon® <NUM> silica from PPG Industries.

In a preferred embodiment, the rubber composition includes carbon black. Representative examples of such carbon blacks include N110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 and N991 grades. These carbon blacks have iodine absorptions (or iodine absorptions numbers) ranging from <NUM>/kg to <NUM>/kg and a DBP number ranging from <NUM><NUM>/<NUM> to <NUM><NUM>/<NUM>. Iodine absorption values are determined according to ASTM D1510 or equivalent.

In one embodiment, the rubber composition may contain sulfur containing organosilicon compounds or silanes. Examples of suitable sulfur containing organosilicon compounds are of the formula:.

in which Z is selected from the group consisting of
<CHM>
where R<NUM> is an alkyl group of <NUM> to <NUM> carbon atoms, cyclohexyl or phenyl; R<NUM> is an alkoxy of <NUM> to <NUM> carbon atoms, or cycloalkoxy of <NUM> to <NUM> carbon atoms; Alk is a divalent hydrocarbon of <NUM> to <NUM> carbon atoms and n is an integer of <NUM> to <NUM>.

In one embodiment, the sulfur containing organosilicon compounds are the <NUM>,<NUM>'-bis(trimethoxy or triethoxy silylpropyl) polysulfides.

In one embodiment, the sulfur containing organosilicon compounds are <NUM>,<NUM>'-bis(triethoxysilylpropyl) disulfide and/or <NUM>,<NUM>'-bis(triethoxysilylpropyl) tetrasulfide. Therefore, as to formula I, Z may be
<CHM>
where R<NUM> is an alkoxy of <NUM> to <NUM> carbon atoms, alternatively <NUM> carbon atoms; Alk is a divalent hydrocarbon of <NUM> to <NUM> carbon atoms, alternatively with <NUM> carbon atoms; and n is an integer of from <NUM> to <NUM>, alternatively <NUM> or <NUM>. In another embodiment, suitable sulfur containing organosilicon compounds include compounds disclosed in <CIT>. In one embodiment, the sulfur containing organosilicon compounds includes <NUM>-(octanoylthio)-<NUM>-propyltriethoxysilane, CH<NUM>(CH<NUM>)<NUM>C(=O)-S-CH<NUM>CH<NUM>CH<NUM>Si(OCH<NUM>CH<NUM>)<NUM>, which is available commercially as NXT™ from Momentive Performance Materials. In another embodiment, suitable sulfur containing organosilicon compounds include those disclosed in <CIT>. In one embodiment, the sulfur containing organosilicon compound is Si-<NUM> from Degussa. The amount of the sulfur containing organosilicon compound in a rubber composition may vary depending on the level of other additives that are used.

It is readily understood by those having skill in the art that the rubber composition may be compounded by methods generally known in the rubber compounding art, such as mixing the various sulfur-vulcanizable constituent rubbers with various commonly used additive materials such as, for example, sulfur donors, curing aids, such as activators and retarders and processing additives, such as oils, resins including tackifying resins and plasticizers, fillers, pigments, fatty acid, zinc oxide, waxes, antioxidants and antiozonants and peptizing agents. As known to those skilled in the art, depending on the intended use of the sulfur vulcanizable and sulfur-vulcanized material (rubbers), the additives mentioned above are selected and commonly used in conventional amounts. Some representative examples of sulfur donors include elemental sulfur (free sulfur), an amine disulfide, polymeric polysulfide and sulfur olefin adducts. In one embodiment, the sulfur-vulcanizing agent is elemental sulfur. The sulfur-vulcanizing agent may for instance be used in an amount ranging from <NUM> phr to <NUM> phr, alternatively within a range of <NUM> phr to <NUM> phr. Typical amounts of tackifier resins, if used, comprise for example <NUM> phr to <NUM> phr, usually <NUM> phr to <NUM> phr. Typical amounts of processing aids, if used, comprise for example <NUM> phr to <NUM> phr (this may comprise in particular oil). Typical amounts of antioxidants, if used, may for example comprise <NUM> phr to <NUM> phr. Representative antioxidants may be, for example, diphenyl-p-phenylenediamine and others, such as, for example, those disclosed in <NPL>. Typical amounts of antiozonants, if used, may for instance comprise <NUM> phr to <NUM> phr. Typical amounts of fatty acids, if used, which can include stearic acid, may for instance comprise <NUM> phr to <NUM> phr. Typical amounts of waxes, if used, may for example comprise <NUM> phr to <NUM> phr. Often microcrystalline waxes are used. Typical amounts of peptizers, if used, may for instance comprise <NUM> phr to <NUM> phr. Typical peptizers may be, for example, pentachlorothiophenol and dibenzamidodiphenyl disulfide.

Accelerators may be preferably but not necessarily used to control the time and/or temperature required for vulcanization and to improve the properties of the vulcanizate. In one embodiment, a single accelerator system may be used, i.e., primary accelerator. The primary accelerator(s) may be used in total amounts ranging from <NUM> phr to <NUM> phr, alternatively <NUM> phr to <NUM> phr. In another embodiment, combinations of a primary and a secondary accelerator might be used with the secondary accelerator being used in smaller amounts, such as from <NUM> phr to <NUM> phr, in order to activate and to improve the properties of the vulcanizate. In addition, delayed action accelerators may be used which are not affected by normal processing temperatures but produce a satisfactory cure at ordinary vulcanization temperatures. Vulcanization retarders might also be used. Suitable types of accelerators that may be used in the present invention are for instance amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates. In one embodiment, the primary accelerator is a sulfenamide. If a second accelerator is used, the secondary accelerator may be for instance a guanidine, dithiocarbamate or thiuram compound. Suitable guanidines include dipheynylguanidine and the like. Suitable thiurams include tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabenzylthiuram disulfide.

The mixing of the rubber composition can be accomplished by methods known to those having skill in the rubber mixing art. For example, the ingredients may be typically mixed in at least two stages, namely, at least one nonproductive stage followed by a productive mix stage. The final curatives including sulfur-vulcanizing agents may be typically mixed in the final stage which is conventionally called the "productive" mix stage in which the mixing typically occurs at a temperature, or ultimate temperature, lower than the mix temperature(s) of the preceding nonproductive mix stage(s). In an embodiment, the rubber composition may be subjected to a thermomechanical mixing step. The thermomechanical mixing step generally comprises a mechanical working in a mixer or extruder for a period of time, for example suitable to produce a rubber temperature between <NUM> and <NUM>. The appropriate duration of the thermomechanical working varies as a function of the operating conditions, and the volume and nature of the components. For example, the thermomechanical working may be from <NUM> to <NUM> minutes.

The rubber composition may be incorporated in a variety of rubber components of the tire (or in other words tire components). For example, the rubber component may be a tread (including tread cap and/or tread base), sidewall, apex, chafer, sidewall insert, wirecoat or innerliner.

In a second aspect of the present invention, the invention is directed to a tire comprising the rubber composition according to the first aspect and or one or more of its embodiments.

For instance, the tire can be a pneumatic tire or nonpneumatic tire, a race tire, a passenger car tire, an aircraft tire, an agricultural tire, an earthmover tire, an off-the-road (OTR) tire, a truck tire, or a motorcycle tire. The tire may also be a radial or bias tire.

Preferably, the tire has a tread comprising the rubber composition.

In a preferred embodiment, the tire is a passenger car tire showing a speed index selected from "W", "Y" or "(Y)" on a lateral side (e.g., sidewall) of the tire. Thus, the tires are UHP, UUHP or race tires allowing to drive at high speed.

Vulcanization of the pneumatic tire of the present invention may for instance be carried out at conventional temperatures ranging from <NUM> to <NUM>. In one embodiment, the vulcanization is conducted at temperatures which are within a range of <NUM> to <NUM>. Any of the usual vulcanization processes may be used such as heating in a press or mold, heating with superheated steam or hot air. Such tires can be built, shaped, molded and cured by various methods which are known and will be readily apparent to those having skill in such art.

The above aspects, their embodiments and/or features may be combined with one another.

Below Table <NUM> shows an Inventive Example in accordance with an embodiment of the present invention and a Comparative Example which is not in accordance with the present invention.

The compositions of Table <NUM> have been tested as tire tread compounds with the results shown below in Table <NUM>. All tests have been carried out on the same passenger car vehicle and under the same test conditions. The test results have been normalized to the results of the tires having treads with the rubber composition of the Comparative Example, wherein higher values are better than lower values.

Claim 1:
A rubber composition comprising from <NUM> phr to <NUM> phr of a styrene butadiene rubber; from <NUM> phr to <NUM> phr of at least one further diene based rubber; and from <NUM> phr to <NUM> phr of a filler; and from <NUM> phr to <NUM> phr of a plasticizer comprising a hydrocarbon resin having a softening point as determined by ASTM E28 within a range of from <NUM> to <NUM>; characterized in that the filler comprises from <NUM> phr to <NUM> phr of silica, from <NUM> phr to <NUM> phr of carbon black, and from <NUM> phr to <NUM> phr of an inorganic metal hydroxide.