Abstract: A guayule rubber processing system and method involves mixing a guayule rubber and at least one solvent blend in an extruder, in order to remove resin found in the guayule miscella and to precipitate the guayule miscella to form a precipitate. The at least one solvent blend has a first solvent configured to precipitate the guayule rubber, and a second solvent configured to swell the resulting precipitate. In particular, a series of the solvent blends may be used at different locations along a length of the extruder and may further include distinct blends of the first solvent and the second solvent, introduced at the different locations, and having different ratios of the first solvent and the second solvent.

Abstract: A tire tread composition includes a quantity of an elastomer including guayule natural rubber, and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer of the tire tread composition may consist entirely of guayule natural rubber. The hydrocarbon resin may be selected to have a predetermined miscibility in the guayule natural rubber. The predetermined miscibility is measured by a deviation of actual Tg from predicted Tg for either the tire tread composition or an elastomer-resin mixture consistent with the elastomer and resin used in the tire tread composition. In particular, the predetermined miscibility in the guayule natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.

Abstract: A latex processing system and method involves mixing a latex and at least one solvent blend in an extruder, in order to remove resin found in the latex and to coagulate the latex to form a coagulum. The at least one solvent blend has a first solvent configured to coagulate the latex, and a second solvent configured to swell the resulting coagulum. In particular, a series of the solvent blends may be used at different locations along a length of the extruder, and may further include distinct blends of the first solvent and the second solvent, introduced at the different locations, and having different ratios of the first solvent and the second solvent.

Abstract: A method for stabilizing a natural rubber such as guayule. The method includes the step of introducing at least one of an Extraction Curves for Guayule Rubber Samples amine and a phenolic anti-oxidant, such as MADA, to a latex form of the rubber under conditions such that the anti-oxidant becomes chemically bound to the rubber. The method includes the further step of subsequently treating the rubber to remove at least a substantial portion of entrained resins. The method can yield a rubber composition of, for example, guayule rubber and including an anti-oxidant chemically bound thereto. The resultant rubber can be suitable for use in tire construction.

Abstract: A guayule rubber processing system and method involves mixing a guayule rubber and at least one solvent blend in an extruder, in order to remove resin found in the guayule miscella and to precipitate the guayule miscella to form a precipitate. The at least one solvent blend has a first solvent configured to precipitate the guayule rubber, and a second solvent configured to swell the resulting precipitate. In particular, a series of the solvent blends may be used at different locations along a length of the extruder and may further include distinct blends of the first solvent and the second solvent, introduced at the different locations, and having different ratios of the first solvent and the second solvent.

Abstract: A tire tread composition includes a quantity of an elastomer including guayule natural rubber, and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer of the tire tread composition may consist entirely of guayule natural rubber. The hydrocarbon resin may be selected to have a predetermined miscibility in the guayule natural rubber. The predetermined miscibility is measured by a deviation of actual Tg from predicted Tg for either the tire tread composition or an elastomer-resin mixture consistent with the elastomer and resin used in the tire tread composition. In particular, the predetermined miscibility in the guayule natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.

Abstract: A tire tread composition includes a quantity of an elastomer including guayule natural rubber, and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer of the tire tread composition may consist entirely of guayule natural rubber. The hydrocarbon resin may be selected to have a predetermined miscibility in the guayule natural rubber. The predetermined miscibility is measured by a deviation of actual Tg from predicted Tg for either the tire tread composition or an elastomer-resin mixture consistent with the elastomer and resin used in the tire tread composition. In particular, the predetermined miscibility in the guayule natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.

Abstract: A process for forming an epoxidized rubber including dissolving a rubber in a solvent and epoxidizing the rubber in the presence of an epoxidation reagent. The solvent is selected such that the rubber is soluble therein but the epoxidized rubber precipitates.

Abstract: A rubber composition including guayule rubber and 15 to 90 phr silica. The rubber can be cis-1,4 polyisoprene and include 15 to 90 phr silica and contain less than 20% of the proteins associated with Hevea rubber and further include at least a trace of resins present in other natural rubbers. The rubber can be cis-1,4 polyisoprene and further include between at least a trace and 3% by weight of resins present in guayule rubber. The rubber composition can further be comprised of a synthetic rubber and include between about 40-100 phr of guayule rubber, and silica. The silica can be hydrophobated.

Abstract: A process for forming an epoxidized rubber including dissolving a rubber in a solvent and epoxidizing the rubber in the presence of an epoxidation reagent. The solvent is selected such that the rubber is soluble therein but the epoxidized rubber precipitates.

Abstract: A rubber composition including guayule rubber and 15 to 90 phr silica. The rubber can be cis-1,4 polyisoprene and include 15 to 90 phr silica and contain less than 20% of the proteins associated with Hevea rubber and further include at least a trace of resins present in other natural rubbers. The rubber can be cis-1,4 polyisoprene and further include between at least a trace and 3% by weight of resins present in guayule rubber. The rubber composition can further be comprised of a synthetic rubber and include between about 40-100 phr of guayule rubber, and silica. The silica can be hydrophobated.

Abstract: A tire tread composition includes a quantity of an elastomer including guayule natural rubber, and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer of the tire tread composition may consist entirely of guayule natural rubber. The hydrocarbon resin may be selected to have a predetermined miscibility in the guayule natural rubber. The predetermined miscibility is measured by a deviation of actual Tg from predicted Tg for either the tire tread composition or an elastomer-resin mixture consistent with the elastomer and resin used in the tire tread composition. In particular, the predetermined miscibility in the guayule natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.

Abstract: A latex processing system and method involves mixing a latex and at least one solvent blend in an extruder, in order to remove resin found in the latex and to coagulate the latex to form a coagulum. The at least one solvent blend has a first solvent configured to coagulate the latex, and a second solvent configured to swell the resulting coagulum. In particular, a series of the solvent blends may be used at different locations along a length of the extruder, and may further include distinct blends of the first solvent and the second solvent, introduced at the different locations, and having different ratios of the first solvent and the second solvent.

Abstract: A tire tread composition includes a quantity of an elastomer and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer includes natural rubber. The hydrocarbon resin has a predetermined miscibility in the natural rubber. The predetermined miscibility is measured by a deviation of actual Tg for an elastomer-resin mixture consistent with the elastomer and hydrocarbon resin used in the tire tread composition from predicted Tg as calculated. In particular, the predetermined miscibility in the natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.

Abstract: A method for manufacturing a modified silica product includes admixing a mercapto silane and a silica to form a hydrophobated silica, and treating the hydrophobated silica with an oxidizing agent. Likewise, a method for manufacturing a silica masterbatch with the modified silica product includes the admixing a mercapto silane solution and a silica slurry to form a hydrophobated silica slurry, and then treating the hydrophobated silica slurry with an oxidizing agent to form a modified silica slurry. The modified silica slurry is blended with a rubber latex, which is then coagulated to form the silica masterbatch. Rubber formulations and articles manufactured with one of the modified silica product and the silica masterbatch are also disclosed.

Abstract: A method for stabilizing a natural rubber such as guayule. The method includes the step of introducing at least one of an Extraction Curves for Guayule Rubber Samples amine and a phenolic anti-oxidant, such as MADA, to a latex form of the rubber under conditions such that the anti-oxidant becomes chemically bound to the rubber. The method includes the further step of subsequently treating the rubber to remove at least a substantial portion of entrained resins. The method can yield a rubber composition of, for example, guayule rubber and including an anti-oxidant chemically bound thereto. The resultant rubber can be suitable for use in tire construction.

Abstract: A functionalized silica product includes particles of a hydrophobated silica having a coating of a polymer. A ratio of the hydrophobated silica to the polymer is from about 0.3/1 to about 100/1. The functionalized silica product may be in the form of a friable crumb or a powder, or in the form of a bale, that may be mixed into an elastomer formulation for a rubber article, such as a tire component.

Abstract: A method for manufacturing a modified silica product includes admixing a mercapto silane and a silica to form a hydrophobated silica, and treating the hydrophobated silica with an oxidizing agent. Likewise, a method for manufacturing a silica masterbatch with the modified silica product includes the admixing a mercapto silane solution and a silica slurry to form a hydrophobated silica slurry, and then treating the hydrophobated silica slurry with an oxidizing agent to form a modified silica slurry. The modified silica slurry is blended with a rubber latex, which is then coagulated to form the silica masterbatch. Rubber formulations and articles manufactured with one of the modified silica product and the silica masterbatch are also disclosed.

Abstract: A functionalized silica product includes particles of a hydrophobated silica having a coating of a polymer. A ratio of the hydrophobated silica to the polymer is from about 0.3/1 to about 100/1. The functionalized silica product may be in the form of a friable crumb or a powder, or in the form of a bale, that may be mixed into an elastomer formulation for a rubber article, such as a tire component.

Abstract: The present invention provides a process for making silica-filled rubber masterbatch using silica hydrophobated with a trimethoxy silane coupling agent that is soluble in an alcohol-water solution containing at least about 70 wt % water. One embodiment uses a mixture of trimethoxy silanes, one or more of which react with rubber to bond the silica to the rubber, and one or more of which do not react with rubber, but do hydrophobate the silica. Hydrophobated silica is mixed with latex polymer and incorporated into rubber during coagulation of the latex, which is preferably coagulated with calcium chloride. The present invention further provides a process for making the trimethoxy silane coupling agents. Preferred trimethoxy silane coupling agents include bis-(3-trimethoxysilylpropyl)-disulfide and bis-(3-trimethoxysilylpropyl)-tetrasulfide.