PROCESS OF PRODUCING SELF-SUPPORTED CATALYSTS
The process features concurrent feeds into the liquid phase of a prepolymerization reaction mixture. These feeds are: a) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, and (ii) a solution in an organic liquid solvent of a metallocene and an aluminoxane and/or metallocene-aluminoxane reaction product; or b) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, (iii) a metallocene optionally in an organic liquid solvent or diluent, and (iv) an aluminoxane optionally in an organic liquid solvent or diluent; or c) separate continuous or substantially continuous feeds of (i) and (ii) and at least one of (iii) and (iv). Particles of catalytically-active, prepolymerized, self-supported olefin polymerization catalyst composition are formed in the reaction medium. The metallocene used as the feed or in making up the feed has at least one polymerizable olefinic substituent in the molecule.