MEDIUM DENSITY ETHYLENE POLYMERS, A PROCESS TO PREPARE THESE POLYMERS AND USE OF CARBONYL GROUP CONTAINING CHAIN TRANSFER AGENTS IN THIS PROCESS

摘要

The present invention relates to an ethylene homo or copolymer having adensity of between 0.923 and 0.935 g/cm3, having amolecular weight distribution M w/M n of between 3 and 10, and comprising from0.10 to 0.50 wt. percent of units derived from a carbonylgroup containing compound, based on the total weight of the homo or copolymer.In addition, the invention relates to a free radicalinitiation polymerization process for the preparation of medium densityethylene polymers or copolymers, comprising reacting ethylene andoptionally one or more comonomers at a high pressure, conveniently between1600 and 4000 kg/cm2, and at temperatures of about 150-330°C in a reactor system consisting of at least one autoclave reactor orof a combination of autoclave and tubular reactors, in the presence offree radical initiators and a carbonyl group containing compound. Finally, theinvention relates to carbonyl group containing chain transferagents to obtain improved polymer processing and performance properties inflat die extrusion processes and applications.