Lately, Anqing Hualan Technology Co., Ltd. developed a preparation method for powered nitrile butadiene rubber (NBR). By this method, nitrile rubber latex is first obtained through the polymerization of acrylonitrile, butadiene, emulgator, electrolyte, mercaptan, initiator, activator and deionized water; then the powered NBR slurry is produced by the coagulation of nitrile rubber latex, deionized water, antiager, polymeric flocculant, flocculant and separant; after that, the powered NBR slurry is put into the centrifugal machine for centrifugal dewatering until the water content is lower than 40%. The resulting wet material shall be put into the whirlwind drying bed by the screw feeder and the entrance of the drying tower shall be 90℃~120℃. After the material separation with 16-goal and 40-goal standard screen, the powered NBR is produced with less than 1.0% of water content.
Compared with coagulating by inorganic salt, the polymeric flocculant is characterized by strong coagulative power and lower dosage. The outlet water after coagulation is low in content of inorganic salts and is easy to dispose with low cost. In addition, this method can reduce the workers labour intensity for compounding salt.