PURPOSE: To obtain a powdery rubber having good dispersibility in asphalt and improved flocculation preventing property and fluidity in storage, by adding a synthetic resin emulsion to a powdery rubber containing a foaming agent dispersed therein.
CONSTITUTION: An anionic or nonionic rubber latex is mixed with 0.1W10pts.wt., based on the dry weight of the above-mentioned rubber latex, anionic water-soluble high polymer, e.g. sodium alginate or sodium carboxymethyl cellulose, and 0.1W100pts.wt., based on the dry weight of the above-mentioned rubber latex, foaming agent, e.g. N,N'-dinitro-pentamethylenetetramine. The resultant mixture solution is then dropped and mixed in an aqueous solution containing 0.1W10pts. wt. cationic water-soluble high polymer or cationic surfactant, e.g. polyvinylpyridine, causing coacervation with the above-mentioned anionic water-soluble high polymer under acidic conditions under acidic conditions, and 1W30pts.wt. synthetic resin emulsion, e.g polystyrene, is added thereto. The resultant mixture is then dehydrated and dried.
ARIYOSHI TAKASHI
HAYASHI TAKAO
EMURA TOKUAKI
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