| abstract |
A process for the production of a product comprising ethylene/propylene copolymer incorporated into a matrix of propylene homopolymer or copolymer comprising the following steps: n (a) contacting propylene or propylene and at least one alpha-olefin having 2 to 8 carbon atoms, and hydrogen, wherein the alpha-olefin is present in a ratio of about 0.01 to about 0.06 mole of alpha-olefin per mole of propylene and the hydrogen is present in a ratio of about 0.001 to about 0.45 mole of hydrogen per mole of combined propylene and alpha-olefin, with a catalyst comprising (i) a catalyst precursor, which includes titanium, magnesium, chlorine, and an electron donor; (ii) a hydrocarbylaluminum cocatalyst; and (iii) a selectivity control agent, which is different from the electron donor, in a first reactor in such a manner that a mixture of a homopolymer of propylene or a copolymer of propylene and alpha-olefin together with active catalyst is produced; n (b) passing the mixture from step (a) into a second reactor; and n (c) adding to the second reactor: n (i) a sufficient amount of ethylene and propylene to provide ethylene/propylene copolymer in an amount of about 20 percent to about 45 percent by weight, based on the weight of the product, said ethylene and propylene being introduced in a ratio of about 10 to about 100 moles of ethylene per mole of propylene; and n (ii) hydrogen in a mole ratio of about 0.1 to about 1.0 mole of hydrogen per mole of combined ethylene and propylene; and n (d) effecting the copolymerization of ethylene and propylene in the second reactor in such a manner that the product is produced. |