Ethylene polymerisation giving high or low branched polymer - using free radical initiators which decompose in 1 hour at 30 to 200 degrees C

摘要

Ethylene or mixts. of 100 moles ethylene with =100 moles copolymerisable monomer contg. 3-20C, are polymsd. at pressures of 500-5,000 bars and temps. of 150-350 degrees C. Polymerisation is carried out in the presence of free radical initiators which decompose over a period of 1 hr. at a temp. of 30-200 degrees C, and opt. polymerisation regulators. Process allows the prodn. of ethylene polymers in high yield with either high or low degree of branching. The low branched polymers are esp. useful for prodn. of high quality packaging foils due to their high transparency and rigidity. In an example, ethylene is polymerised at 1500 bars and a temp. of 248 degrees C using di(2-ethylhexyl)peroxy dicarbonate as initiator to give a polymer with a density of 0.924 g./cm3.