| 摘要 |
There is disclosed a process for the production of tack-free, pourable, filler containing elastomer powder which comprises (a) dispersing a carbon black filler in water; (b) mixing the thus dispersed carbon black filler with an elastomer latex; (c) coagulating the thus produced mixture of elastomer latex and carbon black with a two-stage coagulation solution; (d) partitioning the thus coagulated suspension with a coating resin; and (e) filtering, washing and drying of the resultant powder, the improvement comprising using as a coating resin a mixture of a styrene/butadiene resin and a styrene/ alpha -methylstyrene or a polystyrene resin wherein the weight ratio of the styrene/butadiene resin to the styrene/ alpha -methylstyrene or polystyrene resin ranges between 4/1 and 1/4, said resins containing a mixture of added surfactants, the first being sodium lauryl sulfate and the second being a nonionic isooctyl phenoxy polyethoxy ethanol which contains 10 moles of ethylene oxide in the polyethoxy portion thereof, said mixture of surfactants being added in an amount at least 4 percent by weight and being in a weight ratio of sodium lauryl sulfate to the nonionic surfactant ranging from 2/1 to 1/2, and wherein the coagulation temperature ranges from 70 DEG to 90 DEG C., and a further improvement of using the coagulating step in (c) a two-step coagulating process, the first being acid/salt and then next using an acid/alum coagulating solution.
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