Preparation of vulcanizable compositions using polymer-filler composites

Abstract

A method for preparing a vulcanizable composition of matter, the method comprising (i) providing a polymer-filler composite, where the polymer-filler composite includes particulate filler dispersed in a first elastomeric composition; (ii) providing a second elastomeric composition; (iii) mixing the polymer-filler composite and the second elastomeric composition to form an initial blend, where said mixing takes place at a mix energy sufficient to provide a drop temperature of from about 100 to about 150 ℃; and (iv) introducing a cure system to the initial blend to form a curative-containing composition; (v) mixing the curative-containing composition to form the vulcanizable composition of matter, where said final mixing takes place at a mix energy sufficient to provide a drop temperature of from about 60 to about 120 ℃.

Description

PREPARATION OF VULCANIZABLE COMPOSITIONS USING POLYMER-FILLER COMPOSITES FIELD OF THE INVENTION

[0001] Embodiments of the present invention are directed toward methods for preparing vulcanizable rubber compositions using polymer-filler composites. According to embodiments of the invention, the polymer-filler composites include guayule rubber, and the polymer-filler composites are combined and mixed under limited energy levels with synthetic or other natural rubber. The resulting vulcanizable compositions are useful in manufacturing tire components. BACKGROUND OF THE INVENTION

[0002] Vulcanizable rubber compositions, such as those that are useful in the manufacture of tires, are typically prepared by mixing vulcanizable polymers with fillers, such as carbon black and silica, as well as other additives such as processing aids and curatives. These compositions are typically solid-state or dry mixed using internal mixing devices that are adapted to impart high shear to compositions.

[0003] It has been proposed to pre-mix one or more of the ingredients with the vulcanizable rubber in the presence of water. This technique, which is referred to as a wet masterbatch technique, typically combines a polymer latex with an aqueous slurry in which the particulate filler is dispersed or suspended. For example, U.S. Publication No. 2019 / 0048150 teaches a wet masterbatch technique wherein an elastomer latex fluid and a particulate slurry fluid are combined. The mixture is then coagulated to form a masterbatch crumb that is dewatered and further processed by dry mixing techniques.

[0004] Solution masterbatch techniques have also been proposed. According to these techniques, the vulcanizable polymers are dissolved in a solvent and combined with additives such as particulate filler and then desolventized, have also been proposed. For example, U.S. Publication No.2013 / 0172446 teaches a method where a polymer cement and a filler are mixed to form a solution masterbatch. The solution masterbatch is then desolventized to form a crumb polymer composition. The crumb is then combined with a low viscosity polymeric or oligomeric liquid and mixed by intermeshing mixing in order toreduce the particle size of the particulate filler since solution mixing is unable to impart adequate shear to reduce filler agglomerates. The filler may include carbon black with a surface area of at least 20 m2 / g, and the use of unpelletized carbon black led to greater dispersions. The polymer solution that is combined with the carbon black has a polymer concentration of about 5 to about 80 wt %. Desolventization can be accomplished by drum drying, extruder drying, vacuum drying, spray drying, and steam desolventization.

[0005] Natural rubber, which is in the form of cis-1,4-polyisoprene, is found in latex form within various trees, shrubs and plants, e.g., Hevea brasiliensis, (i.e., the Amazonian rubber tree), Castilla elastica (i.e., the Panama rubber tree), various Landophia vines (L. kirkii, L. heudelotis, and L. owariensis), various dandelions (i.e., Taraxacum species of plants), and Parthenium argentatum (guayule shrubs). The latex of the guayule shrub is trapped intracellularly in the plant cells, which is in contrast to other sources, such as that of the Heavea tree, which is trapped intercellularly. As a result, guayule shrub plant cells must be ruptured to obtain the natural latex. The product obtained from guayule shrub is therefore believed to be unique from at least the standpoint that it contains several constituents, such as resin and low molecular weight polymers. Several purification techniques have been developed to isolate the high molecular weight fractions cis-1,4-polyisoprene, which enables use of the rubber in industrially significant uses. SUMMARY OF THE INVENTION

[0006] One or more embodiments of the present invention provide a method for preparing a vulcanizable composition of matter, the method comprising (a) providing a polymer-filler composite and an elastomer; (b) mixing the polymer-filler composite and the elastomer to form a masterbatch, where said mixing takes place at a mix energy sufficient to provide a drop temperature of from about 100 to about 150 ℃; and (c) introducing a cure system to the masterbatch and conducting a final mixing to form the vulcanizable composition of matter, where said final mixing takes place at a mix energy sufficient to provide a drop temperature of from about 60 to about 120 ℃.

[0007] Other embodiments of the present invention provide a method for preparing a vulcanizable composition of matter, the method comprising a vulcanizable composition ofmatter prepared a method including (i) providing a polymer-filler composite, where the polymer-filler composite includes particulate filler dispersed in a first elastomeric composition; (ii) providing a second elastomeric composition; (iii) mixing the polymer-filler composite and the second elastomeric composition to form an initial blend, where said mixing takes place at a mix energy sufficient to provide a drop temperature of from about 100 to about 150 ℃; and (iv) introducing a cure system to the initial blend to form a curative- containing composition; (v) mixing the curative-containing composition to form the vulcanizable composition of matter, where said final mixing takes place at a mix energy sufficient to provide a drop temperature of from about 60 to about 120 ℃.

[0008] Still other embodiments provide a method for preparing a vulcanizable composition of matter, the method comprising (i) providing a polymer-filler composite, where the polymer-filler composite includes particulate filler dispersed within a rubber; (ii) introducing the polymer-filler composite to a vulcanizable rubber to form a masterbatch; and (iii) introducing a curative to the masterbatch to form a vulcanizable composition of matter.

[0009] Yet other embodiments of the present invention provide the vulcanizable compositions and vulcanizates prepared from the foregoing methods.

[0010] Still other embodiments provide for the use of a polymer-filler composites in the preparation of a rubber vulcanizates that are useful in the preparation of tire components. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0011] Embodiments of the present invention are based, at least in part, on the discovery of a method for preparing vulcanizable compositions using polymer-filler composites. In one or more embodiments, the polymer-filler composites include particulate filler dispersed within guayule rubber. The polymer-filler composites are mixed, in the solid state, with additional rubber and a curative to form the vulcanizable compositions. In one or more embodiments, improved vulcanizate properties are realized when mixing takes place at lower mix energy. While conventional practice suggests that high-energy mixing of rubber and filler, which typically occurs in the absence of a curative, is necessary to achieve proper filler dispersion, desirable vulcanizate properties are achieved when the polymer- filler composites are employed and mixed at lower mix energies.POLYMER-FILLER COMPOSITES

[0012] As indicated above, the methods of the present invention employ polymer-filler composites, which may simply be referred to as composites. In one or more embodiments, these composites include particulate filler dispersed within a rubber, which may also be referred to as an elastomer. In one or more embodiments, the rubber is a guayule polymer. Additionally, the polymer-filler composites may include other constituents including those constituents obtained from the guayule plant. Also, the polymer-filler composites may include constituents introduced during the processes of preparing the composites. GUAYULE POLYMER

[0013] Guayule polymer is polymer obtained from guayule plant (Parthenium argentatu). This polymer is generally characterized as a cis-1,4-polyisoprene, which may be referred to as guayule polymer, guayule polyisoprene, guayule elastomer, or guayule rubber.

[0014] In one or more embodiments, the guayule polymer (i.e. cis-1,4-polyisoprene)may be characterized by a number average molecular weight (Mn) of greater than 150, inother embodiments greater than 200, and in other embodiments greater than 225 kg / mol. In one or more embodiments, guayule polymer may have a number average molecularweight (Mn) of from about 150 to about 500 kg / mol, in other embodiments from about 200to about 450 kg / mol, and in other embodiments from about 225 to about 400 kg / mol. In these or other embodiments, the guayule polymer may have a weight average molecularweight (Mw) of greater than 800, in other embodiments greater than 900, and in otherembodiments greater than 950 kg / mol. In one or more embodiments, guayule polymer mayhave a weight average molecular weight (Mw) of from about 800 to about 3000 kg / mol, inother embodiments from about 900 to about 2000 kg / mol, and in other embodiments from about 950 to about 1500 kg / mol. In one or more embodiments, the guayule polymer has amolecular weight distribution (Mw / Mn) of less than 7, in other embodiments less than 6, inyet other embodiments less than 5.5, and in still other embodiments less than 5. In one or more embodiments, guayule polymer may have a molecular weight distribution of from about 3 to about 7, in other embodiments from about 4 to about 6, and in otherembodiments from about 4.5 to about 5. The polymer molecular weight (Mwand Mn) canbe determined by gel permeation chromatography (GPC) using THF as a solvent and polystyrene standards.

[0015] In one or more embodiments, the solids portion of the guayule cement includes greater than 85 wt %, in other embodiments greater than 90 wt %, and in other embodiments greater than 95 wt % cis-1,4-polyisoprene, based upon the total weight of the solids portion of the cement. In one or more embodiments, the solids portion of the cement includes from about 85 to about 99 wt %, in other embodiments from about 90 to about 98 wt %, and in other embodiments from about 95 to about 97 wt % cis-1,4-polyisoprene, based on the total weight of the solids portion of the cement. OBTAINING GUAYULE POLYMER

[0016] As noted above, the guayule polymer is obtained from a guayule plant. In one or more embodiments, the process for obtaining the polymer from the plant may include providing guayule plant material, mechanically fracturing the plant material, extracting organic material from the fractured plant material to form a miscella, and fractionating the miscella to provide a cement or swollen polymer mass. The swollen polymer mass or cement may then be diluted to provide the cement with the desired solids content.

[0017] In one or more embodiments, the step of fracturing the guayule plant may include mechanically rupturing the stems by, for example, chopping, grinding, and / or macerating dried guayule stems. In one or more embodiments, these stems may include less than about 15 wt %, or in other embodiments less than 10 wt % leaves. In these or other embodiments, dried guayule stems include those that contain less than 25 wt %, or in other embodiments from about 5 to about 20 wt % moisture.

[0018] In one or more embodiments, the step of extracting the organic material from the fractured plant material includes combining the fractured plant material with a solvent that is adapted to dissolve the organic matter of the fractured plants. In one or more embodiments, the solvent includes a mixture of a hydrocarbon solvent (non-polar) and a polar organic solvent (e.g.30 wt % acetone and 70 wt % hexanes). Those skilled in the art will be able to readily select an appropriate amount of solvent mixture to combine with the fractured plant material. For example, it may be common to add sufficient solvent to provide a weight ratio of solvent to bagasse of about 2:1 to about 4:1. The organic material that is dissolved in the solvent mixture is referred to as the miscella, and the miscella is thenseparated from the bagasse, which is the residual woody tissue. The separation of the miscella and the bagasse can be accomplished by using one or more known techniques including a multi-stage extraction technique and / or a countercurrent extraction technique.

[0019] Once the miscella is substantially separated from the bagasse, the miscella undergoes the step of fractionating to, among other things, separate those materials that are soluble in polar solvent (e.g. resin) from those constituents that are soluble in non-polar solvent (e.g. cis-1,4-polyisoprene). In one or more embodiments, the fractionating step includes the use of multistage countercurrent fractionation with concomitant addition of polar solvent (e.g. acetone) countercurrent to the flow of the miscella. Countercurrent fractionation and production of a swollen rubber mass is described, for example, in W. W. Schloman Jr., et al., “Processing Guayule for Latex and Bulk Rubber,” Industrial Crops and Products, 22, 41-47 (2005).

[0020] In one or more embodiments, the miscella can be diluted with additional acetone to precipitate the cis-1,4-polyisoprene in the form of a swollen rubber mass. The swollen rubber mass can then be diluted with additional hydrocarbon solvent or a mixture of at least one hydrocarbon solvent and at least one polar organic solvent to produce a cement with a desired solids content. OTHER CONSTITUENTS FROM GUAYULE PLANT

[0021] As described above, the polymer-filler composites may include additional constituents that are obtained from the guayule plant. In one or more embodiments, these additional constituents include guayule resin. As those skilled in the art appreciate, guayule resin generally refers to non-polyisoprene low molecular weight compounds that generally have a molecular weight of less than about 3000 g / mole. Examples of compounds within the resin include, but are not limited to, monoterpenes, triterpenes (Argentatin A, B and C), sesquiterpene compounds (Guayulin A and B) and fatty acids (as free fatty acid, monoglycerides, diglycerides, triglycerides, or a combination thereof). Additionally, solids portion of the cement may include low molecular weight polyisoprene polymers and oligomers.

[0022] In one or more embodiments, the non-filler portion of the polymer-filler composites may be characterized by a relatively low content of guayule resin. For example, the non-filler portion of the polymer-filler composites may include less than 7 wt %, in otherembodiments less than 6 wt%, and in other embodiments less than 5 wt % guayule resin or low molecular weight polyisoprene, based upon the total weight of the non-filler portion of the polymer-filler composites. In one or more embodiments, the non-filler portion of the polymer-filler composites includes from about 0.5 to about 7 wt %, in other embodiments from about 1 to about 6 wt %, and in other embodiments from about 2 to about 4 wt % guayule resin or low molecular weight polyisoprene, based on the total weight of the non- filler portion of the polymer-filler composites. OTHER ADDED CONSTITUENTS

[0023] As described above, the polymer-filler composites may include additional constituents that are added during formation of the composites. In one or more embodiments, the polymer-filler composites may include an antidegradant such antioxidants and antiozonants. Examples of useful antidegradants include N,N'disubstituted-p-phenylenediamines, such as N-1,3-dimethylbutyl-N'phenyl-p- phenylenediamine (6PPD), N,N'-Bis(1,4-dimethylpently)-p-phenylenediamine (77PD), N- phenyl-N-isopropyl-p-phenylenediamine (IPPD), and N-phenyl-N'-(1,3-dimethylbutyl)-p- phenylenediamine (HPPD). Other examples of antidegradants include, acetone diphenylamine condensation product (Alchem BL), 2,4-trimethyl-1,2-dihydroquinoline (Alchem TMQ), octylated Diphenylamine (Alchem ODPA), and 2,6-di-t-butyl-4-methyl phenol (BHT).

[0024] When present, the polymer-filler composites may include less than 1 wt %, in other embodiments less than 0.5 wt %, and in other embodiments less than 0.3 wt % antidegradant, based on the total weight of the non-filler portion of the composites. In one or more embodiments, the composites include from about 0.05 to about 1 wt %, in other embodiments from about 0.07 to about 0.5 wt %, and in other embodiments from about 0.1 to about 0.3 wt % antidegradant, based on the total weight of the non-filler portion of the composites. FILLER PARTICLES

[0025] As described above, the polymer-filler composites include particulate filler, which may also be described as filler particles. In one or more embodiments, the filler particles include polymer-reinforcing filler, which may also be referred to as rubber- reinforcing filler or simply reinforcing filler. As those skilled in the art appreciate,reinforcing filler includes carbon black filler particles. According to embodiments of the invention, carbon black is added in sufficient amounts to provide a desired weight ratio of carbon black to guayule rubber. CARBON BLACK

[0026] In one or more embodiments, useful carbon blacks include furnace blacks, channel blacks, and lamp blacks. More specific examples of carbon blacks include super abrasion furnace blacks, intermediate super abrasion furnace blacks, high abrasion furnace blacks, fast extrusion furnace blacks, fine furnace blacks, semi-reinforcing furnace blacks, medium processing channel blacks, hard processing channel blacks, conducting channel blacks, and acetylene blacks.

[0027] In one or more embodiments, the carbon blacks employed in preparing the solution masterbatch may have a surface area of greater than 100 m2 / g, in other embodiments greater than 115 m2 / g, and in other embodiments greater than 130 m2 / g. In these or other embodiments, the carbon blacks have a surface area of from about 100 to about 200 m2 / g, in other embodiments from about 115 to about 175 m2 / g, and in other embodiments from about 130 to about 150 m2 / g. For purposes of this specification, and unless otherwise specified, carbon black surface area values are reported as N2 surface area determined by ASTM D-6556-19a.

[0028] In one or more embodiments, the carbon black that is combined with the guayule cement is unpelletized. In other embodiments, the carbon black is pelletized using conventional carbon black pelletization techniques, and then the carbon black pellets are ground or otherwise mechanically manipulated to achieve a desired particle size (e.g. milled). In yet other embodiments, the carbon black is pelletized to a desired particle size.

[0029] In one or more embodiments, the carbon black that is added to the guayule cement is characterized by a median particle size (i.e. D50) of less than 65 nm, in other embodiments less than 60 nm, and in other embodiments less than 55 nm. In these or other embodiments, the carbon black is characterized by a median particle size of greater than 35 nm, in other embodiments greater than 40, and in other embodiments greater than 45 nm. In one or more embodiments, the median particle size of the carbon black is from about 35to about 65 nm, in other embodiments from about 40 to about 60 nm, and in other embodiments from about 45 to about 55 nm. PREPARATION OF POLYMER-FILLER COMPOSITES

[0030] The polymer-filler composites employed in the present invention may be prepared by a method that includes (i) providing a guayule cement, (ii) introducing filler particles to the cement to form a solution masterbatch, and (iii) desolventizing the solution masterbatch to form polymer-filler composites. PROVIDING A GUAYULE CEMENT

[0031] In one or more embodiments, a guayule cement may be provided as follows. This cement includes polymer obtained from guayule and dissolved in an organic solvent. The polymer is included in the solids portion of the cement, and other constituents, which are disclosed below, may also be included in the solids portion of the cement. The solids portion may include dissolved solids and suspended or dispersed solids.

[0032] In one or more embodiments, the guayule cement has a solids concentration of less than 12 wt %, in other embodiments less than 10 wt %, in other embodiments less than 9 wt %, and in other embodiments less than 8 wt %, based on the total weight of the cement. In these or other embodiments, the guayule cement has a solids concentration of greater than 4 wt %, in other embodiments greater than 5 wt %, and in other embodiments greater than 6 wt %, based on the total weight of the cement. In one or more embodiments, the guayule cement has a solids concentration of from about 4 to about 12 wt %, in other embodiments from about 4 to about 10 wt %, in other embodiments from about 5 to about 9 wt %, and in other embodiments from about 6 to about 8 wt %, based on the total weight of the cement.

[0033] In one or more embodiments, the guayule cement includes a generally non-polarhydrocarbon solvent, which may be selected from C5to C10straight chain hydrocarbons, C5toC10branched chain hydrocarbons, C5to C10cyclic hydrocarbons, C6to C10aromatichydrocarbons, and mixtures thereof. In various embodiments, combinations of solvents, including those that provide an azeotropic mixture, may be employed.

[0034] Specific examples of non-polar hydrocarbon solvents include pentane isomers such as n-pentane, iso-pentane, neo-pentane, and mixtures thereof, and hexane isomers suchas n-hexane, iso-hexane, 3-methylpentant, 2,3-dimethylbutane, neo-hexane, cyclohexane,and mixtures thereof. Other useful examples include C6to C10aromatic hydrocarbons suchas benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, mesitylene, 2-ethyltoluene, 3-ethyltoluene, 4-ethyltoluene, and mixtures thereof.

[0035] In one or more embodiments, the guayule cement includes a mixture of a non- polar hydrocarbon solvent and a polar organic solvent. Useful polar organic solvents includeacetone, C1-C4alcohols, C2-C4diols, and mixtures thereof. In particular embodiments, thesolvent is a mixture of acetone and hexanes. In other particular embodiments, the solvent is a mixture of acetone and iso-hexane. In yet other particular embodiments, the solvent is a mixture of iso-hexane, cyclohexane and acetone.

[0036] In one or more embodiments, where the solvent is a mixture of polar and non- polar solvents, the mixture may include less than 50 wt %, in other embodiments less than 40 wt %, in other embodiments less than 30 wt %, and in other embodiments less than 20 wt % polar solvent, with the balance including non-polar solvent. In one or more embodiments, the mixture may include from about 1 to about 50 wt %, in other embodiments from about 10 to about 45 wt %, and in other embodiments from about 20 to about 40 wt % polar solvent with the balance including non-polar solvent. FORMING SOLUTION MASTERBATCH

[0037] Once the desired guayule cement is provided to the process, filler particles are introduced to the cement to form a solution masterbatch. In certain embodiments, additional materials are introduced to the cement in forming the solution masterbatch. The solution masterbatch may be mixed by using conventional techniques for mixing solutions. CHARACTERISTICS OF SOLUTION MASTERBATCH

[0038] In one more embodiments, the solution masterbatch is characterized by a solids content (i.e. the relative weight of the polymer and filler to the overall composition) that is less than 15 wt %, in other embodiments less than 13 wt %, and in other embodiments less than 12 wt %, based on the total weight of the masterbatch. In these or other embodiments, the solids content of the masterbatch is greater than 5 wt %, in other embodiments greater than 7 wt %, and in other embodiments greater than 8 wt %, based on the total weight ofthe masterbatch. In one or more embodiments, the solids content of the masterbatch is from about 5 to about 15 wt %, in other embodiments from about 7 to about 13 wt %, and in other embodiments from about 8 to about 12 wt %, based on the total weight of the masterbatch.

[0039] In one more embodiments, the solution masterbatch may be characterized by the weight of carbon black relative to the weight of the polymer. In one or more embodiments, the solution masterbatch includes less than 90, in other embodiments less than 80, and in other embodiments less than 70 parts by weight carbon black per 100 parts by weight polymer. In these or other embodiments, the solution masterbatch includes greater than 30, in other embodiments greater than 40, and in other embodiments greater than 50 parts by weight carbon black per 100 parts by weight polymer. In one or more embodiments, the solution masterbatch includes from about 30 to about 90, in other embodiments from about 40 to about 80, and in other embodiments from about 50 to about 70 parts by weight carbon black per 100 parts by weight polymer. FILLER INTRODUCTION

[0040] Several techniques can be employed to introduce the filler to the guayule cement. In one or more embodiments, the filler is introduced directly to the cement in the form of a dry solid particulate. For example, the cement may be contained within a conventional stirred-tank reactor, and the filler can be added directly to the cement from the head space of the reactor in the form of a dry solid particulate.

[0041] In other embodiments, the filler particles are pre-mixed with a carrier prior to being introduced to the cement. In one or more embodiments, the filler particles are dissolved or dispersed in a solvent to form solution or dispersion, which may be referred to as a filler-solvent mixture, and the filler-solvent mixture is introduced to the cement. For example, where the cement is contained in a conventional stirred-tank reactor, the filler- solvent mixture can be introduced to the cement via the headspace of the reactor, or in the other embodiments, the mixture can be injected into the cement by an inlet located below the liquid level of the reactor or via a conduit extending into the liquid level of the reactor.

[0042] In those embodiments where a filler-solvent mixture is formed, the filler- solvent mixture may be characterized by a solids content (i.e. the weight of the filler relative to the total weight of the mixture with the balance including the weight of thesolvent) of less than 15 wt %, in other embodiments less than 12 wt %, and in other embodiments less than 10 wt % filler, based on the total weight of the mixture. In these or other embodiments, the mixture may include from about 3 to about 15 wt %, in other embodiments from about 4 to about 12 wt %, and in other embodiments from about 5 to about 10 wt % filler, based on the total weight of the mixture.

[0043] Where a filler-solvent mixture is formed, the solvent employed to make the mixture may include a hydrocarbon solvent as described above with respect to the guayule cement. In other embodiments, the solvent may include a blend of hydrocarbon solvent and polar organic solvent (e.g.30 wt % acetone and 70 wt % hexanes). OPTIONAL CONCENTRATING OF SOLUTION MASTERBATCH

[0044] In one or more embodiments, the solution masterbatch is optionally concentrated before direct desolventization. This can be accomplished by employing conventional techniques such as vaporizing some of the solvent by heat and / or pressure manipulation. As the skilled person will recognize, the amount of solvent can be reduced by heating the solution masterbatch to the boiling point (at a given pressure) of at least one of the solvents to thereby vaporize the solvent. In one or more embodiments, the solution masterbatch is heated within CSTR at atmospheric conditions to boil off a portion of the solvent within the masterbatch.

[0045] In one or more embodiments, the optional step of concentrating the solution masterbatch reduces the amount of solvent present in the masterbatch by greater than 5 wt %, in other embodiments by greater than 10 wt %, and in other embodiments by greater than 15 wt % based on the total weight of the solvent within the masterbatch. In these or other embodiments, the optional step of concentrating the solution masterbatch reduces the amount of solvent by no more than 60 wt %, in other embodiment by no more than 50 wt %, and in other embodiments by no more than 40 wt % based on the total weight of the solvent within the masterbatch.

[0046] In one or more embodiments, the solution masterbatch, after the optional step of concentrating, may be characterized by a solids content (i.e. the relative weight of the polymer and filler to the overall composition, which includes the solvent) of less than 20 wt %, in other embodiments less than 18 wt %, and in other embodiments less than 15 wt % solids based on the total weight of the masterbatch. In these or other embodiments, thesolution masterbatch, after the optional step of concentrating, may be characterized by a solids content of greater than 8 wt %, in other embodiments greater than 10 wt %, and in other embodiments greater than 12 wt % solids, based on the total weight of the masterbatch. In one or more embodiments, the solution masterbatch, after the optional step of concentrating, may be characterized by a solids content of from about 8 to about 20 wt %, in other embodiments from about 10 to about 18 wt %, and in other embodiments from about 12 to about 15 wt % solids, based on the total weight of the masterbatch. DIRECT DESOLVENTIZATION

[0047] As indicated above, the solution masterbatch is desolventized to form a polymer-filler composite, which may also be referred to as rubber-filler composite, or simply as a composite. According to embodiments of the invention, the solution masterbatch is directly desolventized, which refers to a process whereby the solvent is separated from the solids portion of the masterbatch (i.e. separated from the polymer and filler) to form a composition that is substantially a solid composite of the polymer and filler. This can be distinguished from indirect desolventization methods such as steam desolventization whereby water is added to drive off the solvent and thereby produce a composition that would include water, polymer, and filler.

[0048] Direct desolventization techniques, as well as the equipment for performing these methods, are generally known in the art. For example, the temperature of the solution masterbatch can be increased or maintained at a temperature sufficient to volatize the solvent. Also, the pressure within the vessel in which the desolventization is conducted can be decreased, which will assist in the volatilization of solvent. Still further, the solution masterbatch can be agitated, which may further assist in the removal of solvent from the masterbatch. In one embodiment, a combination of heat, decreased pressure, and agitation can be employed.

[0049] In one embodiment, the temperature of the solution masterbatch, together with the pressure of the environment in which the solution masterbatch is devolatilized (i.e. within the desolventization vessel) is adjusted to promote devolatilization. For example, the desolventization step may take place at a temperature of greater than 35 °C, in other embodiments greater than 37 °C, in other embodiments greater than 40 °C, in other embodiments greater than 50 °C, in other embodiments greater than 75 °C, in otherembodiments greater than 100 °C, in other embodiments greater than 110 °C, and in other embodiments greater than 120 °C under pressures of from about -5 to about -30 inches Hg. In one or more embodiments, the step of desolventization takes place at a temperature of from about 35 to about 160 °C, in other embodiments from about 37 to about 140 °C, and in other embodiments from about 40 to about 130 °C under pressures of from about -5 to about -30 inches Hg.

[0050] In one or more embodiments, a threshold amount of work is delivered to the solution masterbatch during the step of desolventization. As the skilled person will appreciate, work can be imparted to the composition by mixing and masticating the composition while subjecting the composition to conditions (such as elevated temperature and / or reduced pressure) that will cause volatilization of the solvent.

[0051] Various techniques can be employed to agitate and / or impart shear on the solution masterbatch during desolventization. As the skilled person will appreciate, agitation can expose greater surface area and thereby facilitate the evolution of solvent. It has also been unexpectedly discovered that shear energy imparted on the solution masterbatch during desolventization has a direct impact on bound rubber.

[0052] In one embodiment, a devolatizer can be employed as the vessel in which the step of desolventization is conducted. Devolatizers can include a devolatizing extruder, which typically includes a screw apparatus that can be heated by an external heating jacket. These extruders are known in the art and may include single and twin-screw extruders.

[0053] Alternatively, devolatizers can include an extruder-like apparatus that includes a shaft having paddles attached thereto. An extruder-like apparatus can include a single shaft or multiple shafts. The shaft can be axial to the length of the apparatus and the flow of the solution masterbatch through the device / vessel. The composition (i.e. solution masterbatch) may be forced through the apparatus by using a pump, and the shaft rotates to thereby allow the paddles to agitate the composition and assist in the evolution of solvent. The paddles can be angled so as to assist movement of the composition through the devolatilizer, although movement of the composition through the devolatilizer can be facilitated by the pump that can direct the composition into the devolatilizer and may optionally be further assisted by an extruder that may optionally be attached in series or atthe end of the devolatilizer (i.e., the extruder helps pull the composition through the devolatilizer).

[0054] Devolatilizers can further include backmixing vessels. In general, these backmixing vessels include a single shaft that includes a blade that can be employed to vigorously mix and masticate the composition (i.e. the solution masterbatch).

[0055] In certain embodiments, combinations of the various devolatilizing equipment can be employed to achieve desired results. These combinations can also include the use of extruders. In one example, a single shaft “extruder-like” devolatilizer (e.g., one including paddles) can be employed in conjunction with a twin-screw extruder. In this example, the solution masterbatch first enters the “extruder-like” devolatilizer followed by the twin- screw extruder. The twin-screw extruder advantageously assists in pulling the composition through the devolatilizer. The paddles of the devolatilizer can be adjusted to meet conveyance needs.

[0056] In another example, a twin shaft “extruder-like” devolatilizer can be employed. In certain embodiments, the paddles on each shaft may be aligned so as to mesh with one another as they rotate. The rotation of the shafts can occur in the same direction or in opposite directions.

[0057] In yet another example, a backmixing volatilizing vessel can be followed by a twin-screw extruder, which can then be followed by a twin shaft extruder-like devolatilizing vessel, which can then be following by a twin screw extruder.

[0058] Devolatilizing equipment is known in the art and commercially available. For example, devolatilizing equipment can be obtained from LIST (Switzerland); Coperion Werner & Phleiderer; or NFM Welding Engineers, Inc. (Ohio). Exemplary equipment available from LIST include DISCOTHERMTM, which is a single shaft “extruder-like” devolatilizer including various mixing / kneading bars or paddles; CRPTM, which is a dual shaft “extruder-like” devolatilizer wherein each shaft correlates with the other; ORPTM, which is a dual shaft devolatilizer wherein each shaft rotates in an opposite direction to the other. CHARACTERISTICS OF RUBBER-FILLER COMPOSITES BOUND RUBBER

[0059] The rubber-filler composites of the present invention are characterized by an advantageous bound rubber content. In one or more embodiments, the polymer-filler composites have a bound filler content that is greater than 40%, in other embodiments greater than 45%, and in other embodiments greater than 50%. In these or other embodiments, the polymer-filler composites are characterized by a bound filler content of from about 40 to about 70%, in other embodiments from about 45 to about 65%, and in other embodiments from about 50 to about 60%.

[0060] For purposes of this specification, and unless otherwise indicated, the following test is used to determine the percent of polymer bound to filler particles in each rubber composition. Bound rubber was measured by immersing small pieces of uncured stocks in a large excess of toluene for three days. The soluble rubber was extracted from the sample by the solvent. After three days, any excess toluene was drained off and the sample was air dried and then dried in an oven at approximately 100 °C to a constant weight. The remaining pieces form a weak coherent gel containing the filler and some of the original rubber. The amount of rubber remaining with the filler is the bound rubber. The bound rubber content is then calculated according to the following: % Bound Rubber = 100 (Wd-F) / R where Wd is the weight of dried gel, F is the weight of filler in gel or solvent insoluble matter (same as weight of filler in original sample), and R is the weight of polymer in the original sample. The bound rubber percentage provides a means of measuring the interaction between the rubber (polymer) within a rubber composition and the filler, with relatively higher percentages of bound rubber indicating increased and beneficial interaction between the rubber (polymer) and filler.

[0061] Data corresponding to “Bound Rubber” can be determined using the procedure described by J. J. Brennan et al., Rubber Chem. and Tech., 40, 817 (1967). FILLER LOADING

[0062] In one or more embodiments, the composites include from about 40 to about 70, in other embodiments from about 45 to about 65, and in other embodiments from about 50 to about 60 parts by weight filler per 100 parts by weight rubber,METHOD OF PREPARING VULCANIZABLE COMPOSITION

[0063] According to the present invention, vulcanizable compositions are prepared by using the polymer-filler composites described herein. In one or more embodiments, the vulcanizable compositions are prepared by (i) combining a polymer-filler composite with an elastomer (i.e. a rubber other than the rubber used in the polymer-filler composites); (ii) mixing the polymer-filler composite and elastomer under sufficient shear to reach a peak temperature indicative of a threshold level of mix energy; (iv) introducing a curative to the masterbatch; and (v) mixing the cure system and masterbatch under sufficient shear to reach a peak temperature indicative of a threshold level of mix energy to thereby form a vulcanizable composition of matter. In one or more embodiments, other ingredients that may be conventionally employed in the art of making vulcanizable rubber compositions may also be added at one or more of the mixing steps outlined above in other mixing steps that may be added to the process.

[0064] The mixing of the polymer-filler composite and elastomer, which step may be referred to as masterbatch mixing, masterbatch mixing step, or masterbatch mixing stage, can be mixed with standard high-shear mixing equipment such as Banbury or Brabender mixers, extruders, kneaders, and two-rolled mills. As the skilled person appreciates, mechanical energy imparted on the composition as part of the shear mixing results in an increase in temperature of the composition. The degree of mixing energy (e.g. shear energy) can be characterized based upon the peak temperature that the composition achieves during mixing. In one or more embodiments, during formation of the masterbatch (i.e. mixing the polymer-filler composites with the added elastomer), the mix energy is characterized by achieving a peak composition temperature (which may also be referred to as drop temperature) of greater than 100 °C, in other embodiments greater than 110 °C, and in other embodiments greater than 120 °C. In these or other embodiments, the masterbatch mix energy achieves a peak composition temperature of less than 150 °C, in other embodiments less than 140 °C, and in other embodiments less than 130 °C. In one or more embodiments, masterbatch mixing achieves a peak temperature of from about 100 to about 150 °C, in other embodiments from about 110 to about 140 °C, and in other embodiments from about 120 to about 130 °C.

[0065] In one or more embodiments, the process of the present invention includes one or more additional mixing steps prior to mixing the masterbatch with the cure system. These additional mixing steps, which may be referred to as remill mixing steps, may include the introduction of additional ingredients such as, for example, a silica coupling agent. In accordance with the present invention, the remill mixing steps take place by using the same or less mixing energy, as indicated by drop temperature, as the masterbatch mixing stage.

[0066] The mixing of the masterbatch and cure system, which step may be referred to as curative mixing, final mixing, or curative mixing stage, for final mixing stage, can be mixed with standard high-shear mixing equipment such as Banbury or Brabender mixers, extruders, kneaders, and two-rolled mills. As with masterbatch mixing, the final mixing step can be characterized by mix energy as indicated by drop temperature. In one or more embodiments, the mix energy of the final mixing stage is characterized by achieving a peak composition temperature of greater than 60 °C, in other embodiments greater than 70 °C, and in other embodiments greater than 80 °C. In these or other embodiments, the final stage mix energy achieves a peak composition temperature of less than 120 °C, in other embodiments less than 110 °C, and in other embodiments less than 100 °C. In one or more embodiments, masterbatch mixing achieves a peak temperature of from about 60 to about 120 °C, in other embodiments from about 70 to about 110 °C, and in other embodiments from about 80 to about 105 °C. ELASTOMER

[0067] As indicated above, the methods of the invention include combining the polymer-filler composites with an elastomer, which may also be referred to as a rubber, an added elastomer, an added rubber, other elastomer, or other rubber. These added elastomers include, without limitation, synthetic elastomeric polymers. Exemplary synthetic elastomeric polymers that are useful in the practice of the present invention (i.e. included within the vulcanizable compositions), which may also be referred to as rubber polymers or vulcanizable polymers, include polydienes and polydiene copolymers. Specific examples of these polymer include, but are not limited to, polybutadiene, poly(styrene-co-butadiene), polyisoprene, poly(styrene-co-isoprene), and functionalized derivatives thereof. Other polymers that may be included in the polymer sample include neoprene, poly(ethylene-co- propylene), poly(styrene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfiderubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, syndiotactic polybutadiene, and mixtures thereof or with polydienes and polydiene copolymers. These elastomers can have a myriad of macromolecular structures including linear, branched, and star-shaped structures. These elastomers may also include one or more functional units, which typically include heteroatoms tethered to the backbone of the polymer.

[0068] In one or more embodiments, the added elastomer includes natural rubber. In one or more embodiments, the natural rubber includes conventional natural rubber, which is that natural rubber obtained from Havea tree. In other embodiments, the natural rubber includes guayule rubber.

[0069] In one or more embodiments, the weight ratio of added elastomer to rubber within the polymer-filler composite is from about 0.2 to about 1:1, in other embodiments from about 0.2:1 to about 0.6:1, in other embodiments from about 0.25:1 to about 0.5:1, and in other embodiments from about 0.3:1 to about 0.4:1. CURATIVE

[0070] As indicated above, the methods of the invention include combining the masterbatch with cure system, which includes a curative, which may also be referred to as a crosslinking agent, rubber curing agent or vulcanizing agents. Curing agents are described in Kirk-Othmer, ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, Vol.20, pgs.365-468, (3rdEd.1982), particularly Vulcanization Agents and Auxiliary Materials, pgs. 390-402, and A.Y. Coran, Vulcanization, ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, (2ndEd.1989), which are incorporated herein by reference. In one or more embodiments, useful cure systems include sulfur or sulfur-based cross-linking agents, organic peroxide-based crosslinking agents, inorganic crosslinking agents, polyamines crosslinking agents, resin crosslinking agents, oxime-based and nitrosamine-based cross-linking agents, and the like. Examples of suitable sulfur crosslinking agents include “rubbermaker's” soluble sulfur; sulfur donating vulcanizing agents, such as an amine disulfide, polymeric polysulfide or sulfur olefin adducts; and insoluble polymeric sulfur. In other embodiments, the crosslinking agents include sulfur and / or sulfur-containing compounds. In other embodiments, the crosslinking agent excludes sulfur and / or sulfur-containing compounds. Vulcanizing agents may be usedalone or in combination. In one or more embodiments, a sulfur-based cure system is employed. The sulfur-based cure system is capable of forming monosulfide, disulfide or polysulfide covalently-bonded bridges between two chains, by reaction with unsaturations initially present in said chains. In one or more embodiments, the crosslinking agent includes sulfur, a sulfur-donating compound, a metal oxide, a bismaleimide, or a benzoquinone derivative. Examples of crosslinking agents include sulfur, dimorpholine disulfide, alkyl phenol disulfide, zinc and magnesium oxides, benzoquinone dioxime and m-phenylene bismaleimide. The curing package may further include one or more vulcanization aids, such as accelerators, retardants, synergists, fillers, heat stabilizers, radiation stabilizers, short-stoppers and moderating agents. OTHER INGREDIENTS

[0071] In addition to the polymer-filler composite and the added rubber, other ingredients may be introduced in forming the masterbatch and / or vulcanizable composition. These other ingredients include, without limitation, reinforcing fillers, plasticizers, carbon black, silica, oils, resins, waxes, metal carboxylates, and cure coagents, anti-degradants, and metal oxides.

[0072] In one or more embodiments, useful carbon blacks include furnace blacks, channel blacks, and lamp blacks. More specific examples of carbon blacks include super abrasion furnace blacks, intermediate super abrasion furnace blacks, high abrasion furnace blacks, fast extrusion furnace blacks, fine furnace blacks, semi-reinforcing furnace blacks, medium processing channel blacks, hard processing channel blacks, conducting channel blacks, and acetylene blacks.

[0073] In one or more embodiments, suitable silica fillers include precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate, aluminum silicate, calcium aluminum silicate, magnesium silicate, and the like.

[0074] In one or more embodiments, the surface area of the silica, as measured by theBET method, may be from about 32 to about 400 m2 / g (including 32 m2 / g to 400 m2 / g),with the range of about 100 m2 / g to about 300 m2 / g (including 100 m2 / g to 300 m2 / g) being preferred, and the range of about 150 m2 / g to about 220 m2 / g (including 150 m2 / gto 220 m2 / g) being included. In one or more embodiments, the silica may be characterized by a pH of about 5.5 to about 7 or slightly over 7, or in other embodiments from about 5.5 to about 6.8. Some of the commercially available silica fillers that can be used include, but are not limited to, those sold under the tradename Hi-Sil, such as 190, 210, 215, 233, and 243, by PPG Industries, as well as those available from Degussa Corporation (e.g., VN2, VN3), Rhone Poulenc (e.g., ZeosilTM1165 MP), and J. M. Huber Corporation.

[0075] In one or more embodiments, silica coupling agents are included in the vulcanizable composition. As the skilled person appreciates, these compounds include a hydrolyzable silicon moiety (often referred to as a silane) and a moiety that can react with a vulcanizable polymer.

[0076] Suitable silica coupling agents include, for example, those containing groups such as alkyl alkoxy, mercapto, blocked mercapto, sulfide-containing (e.g., monosulfide- based alkoxy-containing, disulfide-based alkoxy-containing, tetrasulfide-based alkoxy- containing), amino, vinyl, epoxy, and combinations thereof. In certain embodiments, the silica coupling agent can be added to the rubber composition in the form of a pre-treated silica; a pre-treated silica has been pre-surface treated with a silane prior to being added to the rubber composition.

[0077] Non-limiting examples of alkyl alkoxysilanes suitable for use in certain embodiments of the fourth embodiment disclosed herein 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.

[0078] Non-limiting examples of bis(trialkoxysilylorgano)polysulfides suitable for use in certain embodiments of the fourth embodiment disclosed herein includebis(trialkoxysilylorgano) disulfides and bis(trialkoxysilylorgano)tetrasulfides. Specific non- limiting examples of bis(trialkoxysilylorgano)disulfides suitable for use in certain exemplary embodiments of the fourth embodiment disclosed herein include, but are not limited to, 3,3'- bis(triethoxysilylpropyl) disulfide, 3,3'-bis(trimethoxysilylpropyl)disulfide, 3,3'- bis(tributoxysilylpropyl)disulfide, 3,3'-bis(tri-t-butoxysilylpropyl)disulfide, 3,3'- bis(trihexoxysilylpropyl)disulfide, 2,2'-bis(dimethylmethoxysilylethyl)disulfide, 3,3'- bis(diphenylcyclohexoxysilylpropyl)disulfide, 3,3'-bis(ethyl-di-sec- butoxysilylpropyl)disulfide, 3,3'-bis(propyldiethoxysilylpropyl)disulfide, 12,12'- bis(triisopropoxysilylpropyl)disulfide, 3,3'-bis(dimethoxyphenylsilyl-2- methylpropyl)disulfide, and mixtures thereof. Non-limiting examples of bis(trialkoxysilylorgano)tetrasulfide silica coupling agents suitable for use in certain embodiments of the fourth embodiment disclosed herein 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 under the tradename Si 69 by Evonik Degussa Corporation.

[0079] Non-limiting examples of mercapto silanes suitable for use in certain embodiments of the fourth embodiment disclosed herein include, but are not limited to, 1- mercaptomethyltriethoxysilane, 2-mercaptoethyltriethoxysilane, 3- mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 2- mercaptoethyltripropoxysilane, 18-mercaptooctadecyldiethoxychlorosilane, and mixtures thereof.

[0080] Non-limiting examples of blocked mercapto silanes suitable for use in certain embodiment of the fourth embodiment disclosed herein include, but are not limited to, those described in U.S. Patent 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 for use herein in certain exemplary embodiments disclosed herein include, but are not limited to, 2-triethoxysilyl-1-ethylthioacetate; 2-trimethoxysilyl-1-ethylthioacetate; 2-(methyldimethoxysilyl)-1-ethylthioacetate; 3- trimethoxysilyl-1-propylthioacetate; triethoxysilylmethyl-thioacetate; trimethoxysilylmethylthioacetate; triisopropoxysilylmethylthioacetate; methyldiethoxysilylmethylthioacetate; methyldimethoxysilylmethylthioacetate; methyldiisopropoxysilylmethylthioacetate; dimethylethoxysilylmethylthioacetate; dimethylmethoxysilylmethylthioacetate; dimethylisopropoxysilylmethylthioacetate; 2- triisopropoxysilyl-1-ethylthioacetate; 2-(methyldiethoxysilyl)-1-ethylthioacetate, 2- (methyldiisopropoxysilyl)-1-ethylthioacetate; 2-(dimethylethoxysilyl-1-ethylthioacetate; 2- (dimethylmethoxysilyl)-1-ethylthioacetate; 2-(dimethylisopropoxysilyl)-1- ethylthioacetate; 3-triethoxysilyl-1-propylthioacetate; 3-triisopropoxysilyl-1- propylthioacetate; 3-methyldiethoxysilyl-1-propyl-thioacetate; 3-methyldimethoxysilyl-1- propylthioacetate; 3-methyldiisopropoxysilyl-1-propylthioacetate; 1-(2-triethoxysilyl-1- ethyl)-4-thioacetylcyclohexane; 1-(2-triethoxysilyl-1-ethyl)-3-thioacetylcyclohexane; 2- triethoxysilyl-5-thioacetylnorbornene; 2-triethoxysilyl-4-thioacetylnorbornene; 2-(2- triethoxysilyl-1-ethyl)-5-thioacetylnorbornene; 2-(2-triethoxy-silyl-1-ethyl)-4- thioacetylnorbornene; 1-(1-oxo-2-thia-5-triethoxysilylphenyl)benzoic acid; 6- triethoxysilyl-1-hexylthioacetate; 1-triethoxysilyl-5-hexylthioacetate; 8-triethoxysilyl-1- octylthioacetate; 1-triethoxysilyl-7-octylthioacetate; 6-triethoxysilyl-1-hexylthioacetate; 1- triethoxysilyl-5-octylthioacetate; 8-trimethoxysilyl-1-octylthioacetate; 1-trimethoxysilyl-7- octylthioacetate; 10-triethoxysilyl-1-decylthioacetate; 1-triethoxysilyl-9-decylthioacetate; 1-triethoxysilyl-2-butylthioacetate; 1-triethoxysilyl-3-butylthioacetate; 1-triethoxysilyl-3- methyl-2-butylthioacetate; 1-triethoxysilyl-3-methyl-3-butylthioacetate; 3-trimethoxysilyl- 1-propylthiooctanoate; 3-triethoxysilyl-1-propyl-1-propylthiopalmitate; 3-triethoxysilyl-1- propylthiooctanoate; 3-triethoxysilyl-1-propylthiobenzoate; 3-triethoxysilyl-1-propylthio- 2-ethylhexanoate; 3-methyldiacetoxysilyl-1-propylthioacetate; 3-triacetoxysilyl-1- propylthioacetate; 2-methyldiacetoxysilyl-1-ethylthioacetate; 2-triacetoxysilyl-1- ethylthioacetate; 1-methyldiacetoxysilyl-1-ethylthioacetate; 1-triacetoxysilyl-1-ethyl- thioacetate; tris-(3-triethoxysilyl-1-propyl)trithiophosphate; bis-(3-triethoxysilyl-1- propyl)methyldithiophosphonate; bis-(3-triethoxysilyl-1-propyl)ethyldithiophosphonate; 3-triethoxysilyl-1-propyldimethylthiophosphinate; 3-triethoxysilyl-1- propyldiethylthiophosphinate; tris-(3-triethoxysilyl-1-propyl)tetrathiophosphate; bis-(3-triethoxysilyl-1-propyl)methyltrithiophosphonate; bis-(3-triethoxysilyl-1- propyl)ethyltrithiophosphonate; 3-triethoxysilyl-1-propyldimethyldithiophosphinate; 3- triethoxysilyl-1-propyldiethyldithiophosphinate; tris-(3-methyldimethoxysilyl-1- propyl)trithiophosphate; bis-(3-methyldimethoxysilyl-1-propyl)methyldithiophosphonate; bis-(3-methyldimethoxysilyl-1-propyl)-ethyldithiophosphonate; 3-methyldimethoxysilyl-1- propyldimethylthiophosphinate; 3-methyldimethoxysilyl-1-propyldiethylthiophosphinate; 3- triethoxysilyl-1-propylmethylthiosulfate; 3-triethoxysilyl-1-propylmethanethiosulfonate; 3- triethoxysilyl-1-propylethanethiosulfonate; 3-triethoxysilyl-1-propylbenzenethiosulfonate; 3-triethoxysilyl-1-propyltoluenethiosulfonate; 3-triethoxysilyl-1- propylnaphthalenethiosulfonate; 3-triethoxysilyl-1-propylxylenethiosulfonate; triethoxysilyl methyl methylthiosulfate; triethoxysilylmethylmethanethiosulfonate; triethoxysilylmethylethanethiosulfonate; triethoxysilylmethylbenzenethiosulfonate; triethoxysilylmethyltoluenethiosulfonate; 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 that sold under the tradename NXT silane (3- octanoylthio-1-propyltriethoxysilane) by Momentive Performance Materials Inc.

[0081] In one or more embodiments, plasticizers include oils and solids resins. Useful oils or extenders that may be employed include, but are not limited to, aromatic oils, paraffinic oils, naphthenic oils, vegetable oils other than castor oils, low PCA oils including MES, TDAE, and SRAE, and heavy naphthenic oils. Suitable 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, safflower oil, corn oil, linseed oil, cotton seed oil, rapeseed oil, cashew oil, sesame oil, camellia oil, jojoba oil, macadamia nut oil, coconut oil, and palm oil. As is generally understood in the art, oils refer to those compounds that have a viscosity that is relatively low compared to other constituents of the vulcanizable composition, such as the resins. In one or more embodiments, the resins may be solids with a Tg of greater than about 20 °C, and may include, but are not limited to, hydrocarbon resins such as cycloaliphatic resins, aliphatic resins, aromatic resins, terpene resins, and combinations thereof. Useful resins include, butare not limited to, styrene-alkylene block copolymers, thermoplastic resins such as C5-basedresins, C5-C9-based resins, C9-based resins, terpene-based resins, terpene-aromaticcompound-based resins, rosin-based resins, dicyclopentadiene resins, alkylphenol-based resins, and their partially hydrogenated resins.

[0082] Other ingredients that are typically employed in rubber compounding may also be added to the rubber compositions. These include accelerators, accelerator activators, additional plasticizers, waxes, scorch inhibiting agents, processing aids, zinc oxide, tackifying resins, reinforcing or hardening resins, fatty acids such as stearic acid, peptizers, and antidegradants such as antioxidants and antiozonants.

[0083] In one or more embodiments, the vulcanizable compositions include a catalyst that serves to promote the reaction between the hydrolyzable groups on the synthetic polymer and silica. These catalysts are generally known in the art and include, for example, strong bases such as, but not limited to, alkali metal alkoxides, such as sodium or potassium alkoxide; guanidines, such as triphenylguanidine, diphenylguanidine, di-o-tolylguanidine, N,N,N',N'-tetramethylguanidine, and the like; and hindered amine bases, such as 1,8- diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, and the like, tertiary amine catalysts, such as N,N-dimethylcyclohexylamine, triethylenediamine, triethylamine, and the like, quaternary ammonium bases, such as tetrabutylammonium hydroxide, and bisaminoethers, such as bis(dimethylaminoethyl)ethers. INGREDIENT AMOUNTS

[0084] The vulcanizable compositions can be characterized by the total polymeric content (i.e. polymer introduced via polymer-filler composites and polymer elastomer added to the vulcanizable composition). In one or more embodiments, the vulcanizable compositions include greater than 20 wt %, in other embodiments greater than 30 wt %, and in other embodiments greater than 40 wt % polymeric content (e.g. elastomer), based on the total weight of the vulcanizable composition. In these or other embodiments, the vulcanizable compositions include less than 80 wt %, in other embodiments less than 70 wt %, and in other embodiments less than 60 wt % polymeric content (e.g. elastomer), based on the total weight of the vulcanizable composition. In one or more embodiments, the vulcanizable compositions include from about 20 to about 80 wt %, in other embodimentsfrom about 30 to about 70 wt %, and in other embodiments from about 40 to about 60 wt % polymeric content (e.g. elastomer), based on the total weight of the vulcanizable composition.

[0085] In one or more embodiments, the polymeric content (e.g. elastomer content) of the polymeric content of the vulcanizable composition includes threshold levels of guayule rubber. In one or more embodiments, the polymeric content of the vulcanizable composition includes greater than 50 wt %, in other embodiments greater than 60 wt %, in other embodiments greater than 70 wt %, and in other embodiments greater than 80 wt % guayule rubber based on the total weight of the polymeric content. In one or more embodiments, the polymeric content of the vulcanizable composition includes less than 100 wt %, in other embodiments less than 95 wt %, in other embodiments less than 90 wt %, and in other embodiments less than 85 wt % guayule rubber based on the total weight of the polymeric content. In one or more embodiments, the polymeric content of the vulcanizable composition include from about 50 to about 100 wt %, in other embodiments from about 60 to about 95 wt %, in other embodiments from about 70 to about 90 wt %, and in other embodiments from about 80 to about 85 wt % guayule rubber, based on the total weight of the polymeric component.

[0086] In one or more embodiments, greater than 50 wt %, in other embodiments greater than 60 wt %, in other embodiments greater than 70 wt %, in other embodiments greater than 80 wt %, and in other embodiments greater than 90 wt % of the guayule rubber within the vulcanizable composition is provided from the polymer-filler composites.

[0087] In one or more embodiments, the vulcanizable compositions include a filler such as carbon black or silica. In one or more embodiments, the vulcanizable compositions include greater than 10 parts by weight (pbw), in other embodiments greater than 35 pbw, and in other embodiments greater than 55 pbw filler (e.g. carbon black and or silica) per one hundred parts by weight of the rubber (phr). In these or other embodiments, the vulcanizable compositions include less than 140 pbw, in other embodiments less than 95 pbw, and in other embodiments less than 75 pbw filler phr. In one or more embodiments, the vulcanizable composition include from about 10 to about 200 pbw, in other embodiments from about 10 to about 140 pbw, in other embodiments from about 35 to about 95 pbw, in other embodiments from about 40 to about 130 pbw, in other embodimentsfrom about 50 to about 120 pbw, and in other embodiments from about 55 to about 75 pbw filler (e.g. carbon black and or silica) phr. Carbon black and silica may be used in conjunction at a weight ratio of silica to carbon black of from about 0.1:1 to about 30:1, in other embodiments of from about 0.5 to about 20:1, and in other embodiments from about 1:1 to about 10:1.

[0088] In one or more embodiments, the vulcanizable compositions include greater than 40 pbw, in other embodiments greater than 45 pbw, in other embodiments greater than 55 pbw, and in other embodiments greater than 60 pbw carbon black phr. In one or more embodiments, the vulcanizable compositions include less than 195 pbw, in other embodiments less than 90 pbw, in other embodiments less than 85 pbw, and in other embodiments less than 80 pbw carbon black phr. In these or other embodiments, the vulcanizable composition includes from about 40 to 100 pbw, in other embodiments from about 45 to 90 pbw, and in other embodiments from about 50 to 80 pbw carbon black phr.

[0089] In one or more embodiments, greater than 50 wt %, in other embodiments greater than 60 wt %, in other embodiments greater than 70 wt %, in other embodiments greater than 80 wt %, and in other embodiments greater than 90 wt % of the carbon black within the vulcanizable composition is provided from the polymer-filler composites.

[0090] In one or more embodiments, where silica is used as a filler, the vulcanizable compositions may include silica coupling agent. In one or more embodiments, the vulcanizable compositions may generally include greater than 1, in other embodiments greater than 2, and in other embodiments greater than 3 pbw silica coupling agent phr. In these or other embodiments, the vulcanizable compositions may generally include less than 40, in other embodiments less than 20, and in other embodiments less than 10 pbw silica coupling agent phr. In one or more embodiments, the vulcanizable compositions include from about 1 to about 40 pbw, in other embodiments from about 2 to about 20 pbw, in other embodiments from about 2.5 to about 15 pbw, and in other embodiments from about 3 to about 10 pbw silica coupling agent phr.

[0091] In these or other embodiments, the amount of silica coupling agent may be defined relative to the weight of the silica. In one or more embodiments, the amount of silica coupling agent introduced to the silica (either in situ or pre-reacted) is from about 1 to about 25 pbw, in other embodiments from about 2 to about 20 pbw, and in other embodimentsfrom about 3 to about 15 pbw silica coupling agent per one hundred parts by weight of the silica.

[0092] The vulcanizable compositions may generally include greater than 5, in other embodiments greater than 10, and in other embodiments greater than 20 pbw plasticizer (e.g. oils and solid resins) phr. In these or other embodiments, the vulcanizable compositions may generally include less than 80, in other embodiments less than 70, and in other embodiments less than 60 pbw plasticizer phr. In one or more embodiments, vulcanizable compositions may generally include from about 5 to about 80, in other embodiments from about 10 to about 70, and in other embodiments from about 20 to about 60 pbw plasticizer phr. In further embodiments, the vulcanizable compositions may include less than 15 pbw, alternatively less than 10 pbw, or less than 5 pbw of liquid plasticizer. In certain embodiments, the vulcanizable compositions are devoid of liquid plasticizer. In alternative embodiments, the vulcanizable compositions may include at least 20 pbw of resin, at least 25 pbw resin or at least 30 pbw resin.

[0093] The skilled person will be able to readily select the amount of vulcanizing agents to achieve the level of desired cure. In particular embodiments, sulfur is used as the cure agent. In one or more embodiments, the vulcanizable compositions may include greater than 0.5 pbw sulfur phr, in other embodiments greater than 1 pbw sulfur phr, and in other embodiments greater than 2 pbw sulfur phr. In these or other embodiments, the vulcanizable compositions may generally include less than 10 pbw sulfur phr, in other embodiments less than 7 pbw sulfur phr, and in other embodiments less than 5 pbw sulfur phr. In one or more embodiments, the vulcanizable compositions may generally include from about 0.5 to about 10 pbw sulfur phr, in other embodiments from about 1 to about 6 pbw sulfur phr, and in other embodiments from about 2 to about 4 pbw sulfur phr. PREPARATION OF VULCANIZATE

[0094] As indicated above, the vulcanizable compositions of the present invention can be cured to prepare various tire components. These tire components include, without limitation, tire treads, tire sidewalls, belt skims, innerliners, ply skims, and bead apex. These tire components can be included within a variety of vehicle tires including passenger tires.

[0095] In one or more embodiments, the vulcanizate is prepared by vulcanizing a vulcanizable composition. The vulcanizable compositions are otherwise prepared usingconventional mixing techniques. The vulcanizable composition is then formed into a green vulcanizate and then subjected to conditions to effect curing (i.e. crosslinking) of the polymeric network.

[0096] In particular embodiments, the vulcanizates of this invention include one or more components of a heavy vehicle tire, such as a tread or undertread of a heavy vehicle tire. As those skilled in the art appreciate, heavy vehicle tires include, for example, truck tires, bus tires, TBR (truck and bus tires), subway train tires, tractor tires, trailer tires, aircraft tires, agricultural tires, earthmover tires, and other off-the-road (OTR) tires. In one or more embodiments, the heavy vehicle tires may new tires as well as those tires that have been re-treaded. Heavy vehicle tires can sometimes be classified as to their use. For example, truck tires may be classified as drive tires (those that are powered by the truck engine) and steer tires (those that are used to steer the truck). The tires on the trailer of a tractor-trailer rig are also classified separately.

[0097] In particular embodiments, heavy vehicle tires are relatively large tires. In one or more embodiments, the heavy vehicle tires have an overall diameter (tread to tread) of greater than 17.5, in other embodiments greater than 20, in other embodiments greater than 25, in other embodiments greater than 30, in other embodiments greater than 40, and in other embodiments greater than 55 inches. In these or other embodiments, heavy vehicle tires have a section width of greater than 10, in other embodiments greater than 11, in other embodiments greater than 12, and in other embodiments greater than 14 inches. EXAMPLES

[0098] In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. The examples should not, however, be viewed as limiting the scope of the invention. The claims will serve to define the invention.

[0099] A vulcanizable composition prepared according to aspects of this invention was prepared and vulcanized. The vulcanizate properties were compared against similar formulations prepared without use of a polymer-filler composite and by using conventional high-shear mixing techniques.

[0100] The vulcanizable composition prepared according to aspects of the present invention was prepared using a polymer-filler composite that includes guayule rubber andcarbon black. This composite was prepared from a solution masterbatch with a rubber to carbon black ratio of 100:55. The polymer-filler composite was then combined with and mixed with poly(styrene-co-butadiene) rubber and polybutadiene in the amounts provided in Table 1. The control compound included the same level of carbon black, guayule rubber, poly(styrene-co-butadiene) rubber and polybutadiene. Both compounds also included the same level and type of curative and other ingredients found in conventional vulcanizable compositions of matter for forming tire treads for TBR tires.

[0101] As noted above, the inventive composition was mixed at relatively low mix energy as indicated by the drop temperature, which was lower than the drop temperature of the control compound. As also noted above, the control composition, which was formed by introducing each of the ingredients directly to the mixer (i.e. not in the form of a polymer-filler composite), was mixed at higher mix energy. Both compounds were mixed for the same amount of time to ensure adequate blending of the synthetic polymers with the composite as shown in Table 2. Table 1 Ctrl T1Table 2 Ctrl T1

[0102] Analytical testing of the compounds, the results of which are shown in Table 3, show an increase in bound rubber for equivalent carbon black loadings. Also, mechanical property testing showed increased tensile strength and improved rolling resistance as indicated by lower tan δ at 60 °C and 100 °C, which results are also provided in Table 3. Table 3 Ctrl T1CB (TGA) (phr) 41.3 41.5

[0010] ar ous mo ca ons an a era ons a do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

CLAIMS 1. A method for preparing a vulcanizable composition of matter, the method comprising: (i) providing a polymer-filler composite, where the polymer-filler composite includes particulate filler dispersed in a first elastomeric composition; (ii) providing a second elastomeric composition; (iii) mixing the polymer-filler composite and the second elastomeric composition to form an initial blend, where said mixing takes place at a mix energy sufficient to provide a drop temperature of from about 100 to about 150 ℃; and (iv) introducing a cure system to the initial blend to form a curative- containing composition; (v) mixing the curative-containing composition to form the vulcanizable composition of matter, where said final mixing takes place at a mix energy sufficient to provide a drop temperature of from about 60 to about 120 ℃.

2. The method of claim 1, where the polymer-filler composite includes carbon black dispersed within guayule rubber.

3. The method of any of the preceding claims, where said step of mixing the polymer- filler composite and the second elastomeric composition takes place at a mix energy sufficient to provide a drop temperature of less than 140 °C.

4. The method of any of the preceding claims, where said step of mixing the polymer- filler composite and the second elastomeric composition takes place at a mix energy sufficient to provide a drop temperature of less than 130 °C.

5. The method of any of the preceding claims, where the polymer-filler composite includes from about 40 to about 70 parts by weight carbon black per 100 parts by weight rubber.

6. The method of any of the preceding claims, where the carbon black has a median particle size (i.e. D50) of less than 65 nm.

7. The method of any of the preceding claims, where the carbon black has a surface area of greater than 100 m2 / g.

8. The method of any of the preceding claims, where the carbon black is non-pelletized.

9. The method of any of the preceding claims, where the guayule rubber is cis-1,4- polyisoprene obtained from guayule.

10. The method of any of the preceding claims, where the polymer-filler composite includes from about 0.5 to about 7 wt % guayule resin or low molecular weight polyisoprene.

11. The method of any of the preceding claims, where the polymer-filler composites have a bound rubber content of greater than 40%.

12. The method of any of the preceding claims, where the elastomer is a synthetic elastomer.

13. The method of any of the preceding claims, where the weight ratio of the second elastomeric composition to the first elastomeric composition is from about 0.2:1 to about 0.6:

1.

14. The method of any of the preceding claims, where the vulcanizable composition is characterized by a polymeric content, and where the total polymeric content of the vulcanizable composition includes greater than 50 wt % guayule rubber.

15. The method of any of the preceding claims, where the vulcanizable composition includes guayule rubber, and where greater than 50 wt % of the guayule rubber is provided by the polymer-filler composite.

16. The method of any of the preceding claims, where the vulcanizable composition includes greater than 45 parts by weight carbon black per 100 parts by weight rubber.

17. The method of any of the preceding claims, where the vulcanizable composition includes carbon black, and where greater than 50 wt % of the carbon black is provided by the polymer-filler composite.

18. A vulcanizable composition of matter prepared by the method of any of the preceding claims.

19. A vulcanizate prepared from the vulcanizable composition of any of the preceding claims.

20. The vulcanizate of any of the preceding claims, where the vulcanizate is a tire tread.

21. The vulcanizate of any of the preceding claims, where the tread is a truck bus tread.

22. A method for preparing a vulcanizable composition of matter, the method comprising: (i) providing a polymer-filler composite, where the polymer-filler composite includes particulate filler dispersed within a rubber; (ii) introducing the polymer-filler composite to a vulcanizable rubber to form a masterbatch; (iii) introducing a curative to the masterbatch to form a vulcanizable composition of matter.

23. The use of a polymer-filler composite in the preparation of a rubber vulcanizate that is useful in the preparation of a tire component.

24. The of any of the preceding claims where the polymer-filler composite includes carbon black dispersed within guayule rubber.

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