Methods for producing polyisoprene latex dispersions

A method for producing a polyisoprene latex dispersion, the method comprising:

• (i) extracting guayule plant material in a solvent to produce a miscella;
• (ii) fractionating the miscella to obtain a preliminary cement;
• (iii) diluting the preliminary cement with a mixture of polar and non-polar hydrocarbon solvent to produce a rubber cement for dispersing, where the rubber cement includes from about 5 wt % to about 10 wt % natural cis-1,4-polyisoprene rubber;
• (iv) circulating water and a surfactant through a circulation system including a continuously stirred tank in fluid communication with a circulation loop including an inline high-shear mixing device, where the water and surfactant mix to form an aqueous surfactant mixture;
• (v) maintaining the continuously stirred tank at steady state conditions;
• (vi) dispersing the rubber cement into the aqueous surfactant mixture circulating through the circulation system to produce a biphasic latex emulsion, where said step of dispersing is controlled to introduce the rubber cement at a weight ratio of rubber cement to water and surfactant within the aqueous surfactant mixture of from about 1:200 to about 1:5 to thereby form the biphasic latex emulsion;
• (vii) homogenizing the biphasic latex emulsion within inline high-shear mixing device while the biphasic latex emulsion circulates through the circulation system;
• (viii) removing a portion of the biphasic latex emulsion from the circulation system;
• and
• (ix) removing organic solvent from the biphasic latex emulsion removed in said step of removing a portion of the biphasic latex emulsion to thereby form a latex wherein the natural cis-1-4, polyisoprene is dispersed within water, and where the method yields less than 10% rubber loss.