| 摘要 |
Polymers of ethylene are obtained by polymerizing ethylene or a mixture of ethylene and an ethylenically unsaturated monomer copolymerizable therewith in a first polymerization zone at an elevated pressure and elevated temperature and in the presence of a free radical initiator to produce an effluent containing ethylene and at least one polymer of ethylene, reducing the pressure in said effluent and further polymerizing ethylene present therein in a second polymerization zone at a lower pressure than that maintained in said first zone and at an elevated temperature in the presence of a free radical initiator. Preferably the pressure in the second reaction zone is at least 3000 p.s.i. lower than that in the first reaction zone. The initiator used in the first reaction zone is oxygen and that in the second reaction zone is a peroxygen compound. |
