Abstract: A process, particularly a gas phase fluidised bed process, for the production of polymers avoids formation of sheets or chunks within the reactor, without the need to use antistatic agents, which can reduce the activity of the catalyst or alter the characteristics of the yielded product. According to the invention, a device generates a corona discharge in the polymerisation reactor during the polymerisation process; an AC voltage difference is applied between the elements which constitute the discharging pair of the device.

Abstract: Disclosed is a process for preparing copolymers which comprises, in the order stated: (1) adding monomers containing unsaturated carbon-to-carbon bonds, a first polymerization initiator, a second polymerization initiator, and a solvent to a reaction vessel; (2) purging the resulting solution with an inert gas; (3) sealing the reaction vessel and pressurizing it by addition of an inert gas to a pressure of from about 20 to about 600 kilopascals over ambient atmospheric pressure; (4) maintaining the temperature within the pressurized reaction vessel at a temperature of from about 50 to about 100.degree. C. for a period of from about 60 to about 300 minutes; (5) thereafter maintaining the temperature within the pressurized reaction vessel at a temperature of from about 80 to about 115.degree. C.

Abstract: A process for the continuous high pressure polymerization of ethylene in a polymerization system which comprises a polymerization zone (A), a high pressure product isolation zone (B), a throttling and control system (C), a low pressure product isolation zone (D), a second throttling and control system (E) and a discharge extruder (F), and wherein, according to the invention, the level of the ethylene polymer in the high pressure product isolation zone (B) and in the low pressure product isolation zone (D) is varied periodically. The process gives an ethylene polymer of improved homogeneity, which when used to manufacture films does not tend to form specks or fisheyes.

Abstract: A process for the high pressure polymerization of ethylene at elevated temperatures in a polymerization zone followed by transfer of the reaction mixture, through a cooling zone, into the separation zone. In this process, the pressure at the cooling zone outlet is periodically reduced briefly, at recurring intervals, these brief pressure reductions being independent of the pressure reductions in the polymerization zone. Using this process, the conversion in the polymerization unit can be increased and a more homogeneous ethylene polymer can be obtained.