Preparation of ethylene polymers by the high-pressure method
AssigneeBasell Polyolefine GmbH
InventorsLars Wittkowski, Andreas Deckers, Wilhelm Weber, Thomas Dröge, Andrei Gonioukh, Frank-Olaf Mähling
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Abstract
A process for preparing ethylene polymers by the high-pressure method comprises dissolving one or more free-radical initiators in one or more ketones of the formula I where R1 and R2 are identical or different and are selected from among C1-C6-alkyl and C3-C12-cycloalkyl and R1 and R2 may also be covalently linked to one another to form a 4- to 13-membered ring, prior to the polymerization, compressing the solution, metering it into the polymerization reactor at one or more points and subsequently carrying out the polymerization at from 150 to 380° C. and from 500 to 4500 bar.
Claims14
A process for preparing polyethylene, comprising:
- dissolving one or more free-radical initiators in one or more ketones of the formula I,
- thereby obtaining a monomer free solution;
- and
- compressing the monomer free solution, to obtain a compressed solution;
- metering said compressed solution into a tube reactor at one or more points;
- and
- subsequently polymerizing ethylene, thereby obtaining a polyethylene having a molecular weight Mw of greater than 40,000 g/mol;
- wherein in formula I, R1 and R2 are identical or different and are C1-C6-alkyl, C3-C12-cycloalkyl or R1 and R2 are covalently linked to one another to form a 4- to 13-membered ring, prior to the polymerization;
- wherein said process proceeds at a temperature of from 140 to 350° C. and a pressure of from 400 to 4500 bar.
Dependencies are inferred from the claim text.