Solid State Properties Of Polyethylene Prepared With Tetrahydroindenyl-Based Catalyst System
AssigneeTotal Petrochemicals Research Feluy
InventorEric Maziers
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Abstract
The present invention discloses articles having excellent dimensional stability, solid state mechanical properties and barrier properties that are produced with a polyethylene resin prepared with a catalyst system based on a bridged bisindenyl ligand.
Claims17
A method for preparing a homopolymer or a copolymer of ethylene that comprises the steps of:
- a) Injecting into the reactor a catalyst system comprising i) a metallocene catalyst component of general formula I
- R″(Ind)2MQ2 (I)
- wherein (Ind) is an indenyl or an hydrogenated indenyl, substituted or unsubstituted, R″ is a structural bridge between the two indenyls to impart stereorigidity that comprises a C1-C4 alkylene radical, a dialkyl germanium or silicon or siloxane, or a alkyl phosphine or amine radical, which bridge is substituted or unsubstituted;
- Q is a hydrocarbyl radical having from 1 to 20 carbon atoms or a halogen, and M is a transition metal Group 4 of the Periodic Table or Vanadium, ii) an activating agent and iii) optionally a support;
- b) injecting into the reactor ethylene monomer at a concentration of at least 6.5 wt %;
- c) injecting an amount of hydrogen such that the ratio H2/C2 in the feed is of less than 85 g/106 g;
- d) maintaining under polymerisation conditions at a temperature of less than 90° C.;
- e) retrieving polyethylene resin.
The method according to any one of the preceding claims wherein the amount of hydrogen in the polymerisation reactor is selected to give a C2/H2 ratio of less than 60 g/106 g.
The method according to any one of the preceding claims wherein the polymerisation temperature is of less than 88° C.
The method according to any one of the preceding claims to produce a polyethylene resin that auto-nucleates.
Use of the polyethylene resin prepared by the method according to any one of the preceding claims to produce finished articles having excellent solid state and barrier properties by rotomoulding, injection moulding, extrusion, thermoforming or slush moulding.
A method for preparing a homopolymer or a copolymer of ethylene that comprises the steps of:
- a) Injecting into the reactor a catalyst system comprising i) a metallocene catalyst component of general formula I
- R″(Ind)2MQ2 (I)
- wherein (Ind) is an indenyl or an hydrogenated indenyl, substituted or unsubstituted, R″ is a structural bridge between the two indenyls that comprises a C1-C4 alkylene radical, a dialkyl germanium or silicon or siloxane, or a alkyl phosphine or amine radical, which bridge is substituted or unsubstituted;
- Q is a hydrocarbyl radical having from 1 to 20 carbon atoms or a halogen, and M is a transition metal Group 4 of the Periodic Table or Vanadium and ii) an activating agent;
- b) injecting into the reactor ethylene monomer at a concentration of at least 6.5 wt %;
- c) injecting an amount of hydrogen such that the ratio H2/C2 in the feed is of less than 85 g/106 g;
- d) maintaining under polymerisation conditions at a temperature of less than 90° C.;
- and
- e) retrieving polyethylene.
Dependencies are inferred from the claim text.