A PROCESS FOR IMPROVING IMPACT STRENGTH OF POLYPROPYLENE COPOLYMERS
Publication Date: 2004-Mar-01
The IP.com Prior Art Database
A method of preparing controlled rheology heterophasic polypropylene copolymers to increase impact strength of such copolymers is described. The process comprises introducing a heterophasic polypropylene copolymer with low initial temperature into an extruder along with a peroxide. The half life of the peroxide is increased compared to a half life of the peroxide when introducing the same copolymer with high initial temperature into an extruder and allowing the peroxide to degrade. The resulting polypropylene copolymer has a notched Izod impact strength that is increased compared to the same copolymer extruded with the peroxide at high initial temperature.