Tubular polymerization reactors and polymers made therein
AssigneeExxonMobil Chemical Patents Inc.
InventorJan Cyriel Donck
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Abstract
Tubular reactor apparatus and processes are provided for improved polymerization including using chain transfer agents and multiple monomer feeds spaced lengthwise along the tubular reactor providing high conversions of monomer into polymer. The invention also relates to polymers made from such a tubular reactor apparatus and processes including those polymers having a low haze value, a density over 0.92 g/cm3 and/or having terminal carbonyl groups. The apparatus and methods uncouple or reduce the dependency between the monomer concentration and transfer agent concentration. The uncoupling in other embodiments may also be varied leading to multiple desirable effects.
Claims10
A process for the polymerization of ethylene comprising:
- (a) combining fresh monomer and recycled monomer and compressing the combined monomer and supplying the monomer using multiple feeds to multiple reaction zones in a tubular reactor for polymerization by a free radical initiator to form a monomer-polymer mixture;
- (b) separating the mixture into a volatile monomer-rich phase and molten polymer-rich phase;
- (c) recycling for compression said monomer-rich phase and supplying said monomer-rich phase to the reactor;
- and
- (d) introducing transfer agent into the reactor to modify the molecular weight of the polymer;
- wherein the transfer agent comprises a chain terminating transfer agent having a transfer coefficient of greater than 0.01, said transfer agent being in a transfer agent rich stream separately from a transfer agent-poor monomer stream of the transfer agent, to a polymerization reaction zone upstream of at least one downstream reaction zone receiving the transfer agent-poor stream so as to achieve a depletion in the concentration of the transfer agent in said at least one downstream reaction zone.
Dependencies are inferred from the claim text.