A process for the preparation of an ultra-high molecular weight ethylene homopolymer having a MFR.sub.21 of 0.01 g/10 min or less, said process comprising: (I) prepolymerising at least ethylene at a temperature of 0 to 90? C. in the presence of a heterogeneous Ziegler Natta catalyst to prepare an ethylene prepolymer having an Mw of 40,000 to 600,000 g/mol; and thereafter in the presence of the prepolymer and said catalyst; (II) polymerising ethylene at a temperature of 55? C. or less, such as 20 to 55? C., to prepare said UHMW ethylene homopolymer; wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer.

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d.sup.1 of from 0.930 to 0.975 g/cm.sup.3, a melt index, I.sub.2.sup.1 of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 2.5; and a second ethylene homopolymer having a density, d.sup.2 of from 0.945 to 0.980 g/cm.sup.3, a melt index, I.sub.2.sup.2 of at least 1.0 g/10 min, and a molecular weight distribution, M.sub.w/M.sub.n of less than 2.5; wherein melt index, I.sub.2.sup.2 of the second ethylene homopolymer is greater than the melt index, I.sub.2.sup.1 of the first ethylene homopolymer. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M.sub.w of ?75,000, a molecular weight distribution, M.sub.w/M.sub.n of less than 4.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d.sup.1 of from 0.930 to 0.975 g/cm.sup.3, a melt index, I.sub.2.sup.1 of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 2.5; and a second ethylene homopolymer having a density, d.sup.2 of from 0.945 to 0.980 g/cm.sup.3, a melt index, I.sub.2.sup.2 of at least 1.0 g/10 min, and a molecular weight distribution, M.sub.w/M.sub.n of less than 2.5; wherein melt index, I.sub.2.sup.2 of the second ethylene homopolymer is greater than the melt index, I.sub.2.sup.1 of the first ethylene homopolymer. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M.sub.w of ?75,000, a molecular weight distribution, M.sub.w/M.sub.n of less than 4.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d.sup.1 of from 0.943 to 0.975 g/cm.sup.3, a melt index, I.sub.2.sup.1 of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 3.0; and a second ethylene homopolymer having a density, d.sup.2 of from 0.950 to 0.985 g/cm.sup.3, a melt index, I.sub.2.sup.2 of at least 500 g/10 min, and a molecular weight distribution, M.sub.w/M.sub.n of less than 3.0; wherein the ratio of the melt index, I.sub.2.sup.2 of the second ethylene homopolymer to the melt index, I.sub.2.sup.1 of the first ethylene homopolymer is at least 50. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M.sub.w of ?75,000, a high load melt index, I.sub.21 of at least 200 g/10 min, a molecular weight distribution, M.sub.w/M.sub.n of from 4.0 to 12.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d.sup.1 of from 0.943 to 0.975 g/cm.sup.3, a melt index, I.sub.2.sup.1 of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 3.0; and a second ethylene homopolymer having a density, d.sup.2 of from 0.950 to 0.985 g/cm.sup.3, a melt index, I.sub.2.sup.2 of at least 500 g/10 min, and a molecular weight distribution, M.sub.w/M.sub.n of less than 3.0; wherein the ratio of the melt index, I.sub.2.sup.2 of the second ethylene homopolymer to the melt index, I.sub.2.sup.1 of the first ethylene homopolymer is at least 50. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M.sub.w of ?75,000, a high load melt index, I.sub.21 of at least 200 g/10 min, a molecular weight distribution, M.sub.w/M.sub.n of from 4.0 to 12.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.

Metallic complexes having indenyl ligands can be used as an ingredient of a catalyst system. The catalyst system can be used in polymerizations of ethylenically unsaturated hydrocarbon monomers that include both olefins and polyenes. Embodiments of the catalyst system can provide interpolymers that include polyene mer and from 40 to 75 mole percent ethylene mer, with a plurality of the ethylene mer being randomly distributed. The catalyst system also can be used in solution polymerizations conducted in C.sub.5-C.sub.12 alkanes, yielding interpolymers that include at least 10 mole percent ethylene mer.

Metallic complexes having indenyl ligands can be used as an ingredient of a catalyst system. The catalyst system can be used in polymerizations of ethylenically unsaturated hydrocarbon monomers that include both olefins and polyenes. Embodiments of the catalyst system can provide interpolymers that include polyene mer and from 40 to 75 mole percent ethylene mer, with a plurality of the ethylene mer being randomly distributed. The catalyst system also can be used in solution polymerizations conducted in C.sub.5-C.sub.12 alkanes, yielding interpolymers that include at least 10 mole percent ethylene mer.

This invention relates bisindenyl metallocene catalyst compounds having long (at least 4 carbon atoms) linear alkyl groups substituted at the two position and substituted or unsubstituted aryl groups at the four position and process using such catalyst compounds, particularly in the solution process at higher temperatures.

This invention relates bisindenyl metallocene catalyst compounds having long (at least 4 carbon atoms) linear alkyl groups substituted at the two position and substituted or unsubstituted aryl groups at the four position and process using such catalyst compounds, particularly in the solution process at higher temperatures.

A method of forming a thermoformed article may include melt extruding polyethylene to form an extruded sheet. The rheological breadth parameter of the polyethylene may change by no more than about 5% after extrusion relative to the rheological breadth parameter of the polyethylene prior to extrusion. The extruded sheet may be thermoformed within a mold to form the thermoformed article. During thermoforming, the extruded sheet may be subjected to solid-state stretching in one or more directions. The thermoformed article may be retrieved from the mold. The polyethylene may have a rheological breadth parameter of from 0.20 to 0.40, a multimodal molecular weight distribution, a polydispersity (Mw/Mn) of from 5 to 18, a density ranging from 0.940 to 0.970 g/cc, may exhibit tensile strain-hardening, or combinations thereof.