Processes for recovering natural rubber from an aqueous natural rubber latex that contains extractables and one or more additives and that is essentially free of lignocellulosic plant material are described. Natural rubber in the latex is separated from the water. Preferably, the amount of non-rubber extractables in the natural rubber is reduced by one or more extraction steps yielding a dried natural rubber.

Processes for recovering natural rubber from an aqueous natural rubber latex that contains extractables and one or more additives and that is essentially free of lignocellulosic plant material are described. Natural rubber in the latex is separated from the water. Preferably, the amount of non-rubber extractables in the natural rubber is reduced by one or more extraction steps yielding a dried natural rubber.

A purified guayule natural rubber is provided which has a particular Mw, Mn, Mw/Mn, resin content and ash content. Also provided are related processes for obtaining the purified guayule natural rubber from an initial co-solvent based miscella which contains solubilized guayule rubber, at least one polar solvent and at least one non-polar solvent using a fractionation system.

A purified guayule natural rubber is provided which has a particular Mw, Mn, Mw/Mn, resin content and ash content. Also provided are related processes for obtaining the purified guayule natural rubber from an initial co-solvent based miscella which contains solubilized guayule rubber, at least one polar solvent and at least one non-polar solvent using a fractionation system.

Provided are a rubber composition for tires that shows a balanced improvement in properties such as fuel economy, processability, heat aging resistance, abrasion resistance, wet-grip performance, performance on snow and ice, and handling stability, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing: a highly purified, modified natural rubber having a pH adjusted to 2-7; carbon black and/or a white filler; and a styrene-butadiene rubber having a styrene content of 30% by mass or more, and also relates to a pneumatic tire formed from the rubber composition.

Provided are a rubber composition for tires that shows a balanced improvement in properties such as fuel economy, processability, heat aging resistance, abrasion resistance, wet-grip performance, performance on snow and ice, and handling stability, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing: a highly purified, modified natural rubber having a pH adjusted to 2-7; carbon black and/or a white filler; and a styrene-butadiene rubber having a styrene content of 30% by mass or more, and also relates to a pneumatic tire formed from the rubber composition.

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.

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.

Provided herein are organic solvent-based processes for the removal of rubber from non-Hevea plants such as guayule shrubs. By the use of the processes, solid purified rubber can be obtained that contains 0.05-0.5 weight % dirt, 0.2-1.5 weight % ash, and 0.1-4 weight % resin (when it has been dried so as to contain 0.8 weight % volatile matter).

Provided herein are organic solvent-based processes for the removal of rubber from non-Hevea plants such as guayule shrubs. By the use of the processes, solid purified rubber can be obtained that contains 0.05-0.5 weight % dirt, 0.2-1.5 weight % ash, and 0.1-4 weight % resin (when it has been dried so as to contain 0.8 weight % volatile matter).