Method to reactor-fill polyolefins by formation of a dual catalyst

Abstract

The present invention relates to a method to reactor-fill polyolefins and to reactor-filled composites obtained from the instant method. More specifically, the present invention relates to a method to reactor-fill polyolefins comprising the steps of (a) adding a catalytic amount of a low activity catalyst to a filler material either during or before polymerization to initiate the formation of atactic polyolefin on the surface and in the pores of the filler; (b) contacting the product of step (a) in no specific order with a high activity catalyst, a cocatalyst, and, if necessary a cocatalyst modifier; and (c) adding an alpha-olefin under olefin polymerization reaction conditions to the reaction product of step (b) to form a reactor-filled composite. The addition of the low activity catalyst to the filler material causes compatibilization of the filler with the matrix polymer, reduced fines, rounded aggregate particles and increased catalyst activity over an un-filled polymerization catalyst system or by that afforded by the elimination of the low activity catalyst obtained from the method of the present invention. The reactor-filled polyolefin composites produced by the instant invention are characterized as having a relatively uniform distribution of filler particles dispensed therein and having improved physical and rheological properties compared to prior art reactor-filled composites.