Process for the preparation of a nitrile rubber comprising: subjecting at least one ,-unsaturated nitrile, at least one conjugated diene and, optionally, one or more further copolymerizable monomers, to emulsion polymerization, in the presence of at least one alkyl thiol containing from 12 to 16 carbon atoms and at least three tertiary carbon atoms and having the sulfur bound to one of said tertiary carbon atoms, at a pH ranging from 7 to 10, preferably from 8 to 9, obtaining a latex; subjecting said latex to coagulation, in the presence of at least one metal sulfate selected from magnesium, sodium, potassium, preferably magnesium, at a temperature higher than or equal to 30 C., preferably ranging from 40 C. to 60 C., obtaining a coagulated nitrile rubber: subjecting said coagulated nitrile rubber to washing with water, in the presence of at least one inorganic base, selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium hydroxide, preferably potassium hydroxide, at a pH higher than or equal to 10, preferably ranging from 11 to 12. The nitrile rubber thus obtained is capable of giving vulcanizable elastomeric compositions having a high vulcanization rate and a good vulcanization yield. Furthermore, said elastomeric compositions cause a low fouling of the molds and can consequently be advantageously used in injection molding processes.

Process for the preparation of a nitrile rubber comprising: subjecting at least one ,-unsaturated nitrile, at least one conjugated diene and, optionally, one or more further copolymerizable monomers, to emulsion polymerization, in the presence of at least one alkyl thiol containing from 12 to 16 carbon atoms and at least three tertiary carbon atoms and having the sulfur bound to one of said tertiary carbon atoms, at a pH ranging from 7 to 10, preferably from 8 to 9, obtaining a latex; subjecting said latex to coagulation, in the presence of at least one metal sulfate selected from magnesium, sodium, potassium, preferably magnesium, at a temperature higher than or equal to 30 C., preferably ranging from 40 C. to 60 C., obtaining a coagulated nitrile rubber: subjecting said coagulated nitrile rubber to washing with water, in the presence of at least one inorganic base, selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium hydroxide, preferably potassium hydroxide, at a pH higher than or equal to 10, preferably ranging from 11 to 12. The nitrile rubber thus obtained is capable of giving vulcanizable elastomeric compositions having a high vulcanization rate and a good vulcanization yield. Furthermore, said elastomeric compositions cause a low fouling of the molds and can consequently be advantageously used in injection molding processes.

Provided herein are organic solvent-based processes for the removal of rubber from aged briquettes made from compressed plant matter (briquettes) of non-Hevea plants. Also provided are aged briquettes made from the compressed plant matter of non-Hevea plants where the briquettes have been aged for either various time period after formation and the rubber within the briquette has retained its a molecular weight to within a specified range.

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).

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.

Disclosed herein are process for removing color bodies from an organic solution comprising guayule resin. The processes include the use of activated carbon.

Disclosed herein are process for removing color bodies from an organic solution comprising guayule resin. The processes include the use of activated carbon.

Provided herein are organic solvent-based processes for the removal of rubber from non-Hevea plants such as TKS. 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 TKS. 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).