Propylene copolymerization process and product

Claim 1

In a process for the production of a copolymer of propylene and ethylene wherein the polymerization of propylene and ethylene is conducted in the presence of a liquid diluent consisting essentially of propylene at pressures sufficient to maintain propylene in liquid phase and at temperatures between about 115° F. and about 165° F. in the presence of a catalyst composition containing the components (a) an aluminum trialkyl at least partially complexed with an aromatic carboxylic acid ester electron donor and (b) a complex of a titanium tri- or tetrahalide with an aromatic carboxylic acid ester electron donor supported on magnesium halide the components (a) and (b) being provided in a molar ratio of Al/Ti between about 10 and about 400, the method of increasing the polymerized ethylene content of the polymer without significantly affecting the isotactic index, which comprises: providing from about 1 to about 9 weight percent ethylene feed based on the weight of propylene feed; adding from about 1 to about 8 percent by weight of butene-1 based on the weight of propylene feed to the polymerization zone, and recovering a polymer product having a propylene content of from about 80 to about 96.5 weight percent, and ethylene content of from about 3 to about 17 weight percent and a butene-1 content of from about 0.5 to about 5 weight percent.