Method of preparing powdered elastomer compositions

In a process for preparing powdered elastomer compositions having the following steps:

• a. coprecipitating from 3 to 19 parts of a first encasement compound selected from the group consisting of starch xanthate and zinc starch xanthate having xanthate degrees of substitution of from 0.2 to 3.0, cationic starch, and their cereal flour analogs with 100 parts of latex solids contained in a latex selected from the group consisting of natural rubber latex, chloroprene latex, polybutadiene latex, styrenebutadiene rubber latex, butadiene-acrylonitrile rubber latex, oil-extended styrene-butadiene rubber latex, and phenol-formaldehyde-extended nitrile rubber latex to form a coprecipitate having a particle diameter of about 1 mm.;
• b. filtering and water washing the coprecipitate resulting from (a);
• c. washing the coprecipitate resulting from step (b) with a water-miscible solvent;
• d. filtering the washed coprecipitate resulting from step (c);
• and
• e. repeating steps (c) and (d) until the filtrate resulting from step (d) contains from 0 to 10 percent water;
• an improvement comprising, as an additional step prior to step (c), supra, resuspending the coprecipitate resulting from step (b), supra, in water and precipitating, in the presence of the resuspended coprecipitate, from 1 to 17 parts per 100 parts of latex solids (phr) of a second encasement compound selected from the group consisting of starch xanthate and zinc starch xanthate having xanthate degrees of substitution of from 0.2 to 3.0, cationic starch, their cereal flour analogs, and sodium stearate, the total amount of first and second encasement compounds being from 4 to 20 phr.