A thermoformable film comprises a polyethylene composition. The polyethylene composition comprises a first polyethylene which is an ethylene copolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution M.sub.w/M.sub.n of <2.3, a second polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 15,000 to 100,000 and a molecular weight distribution M.sub.w/M.sub.n of <2.3, and a third polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution M.sub.w/M.sub.n of >2.3, where the first polyethylene has more short chain branching than the second polyethylene or the third polyethylene. The polyethylene composition has a melt flow ratio (I.sub.21/I.sub.2) of ≤50 and an area Dimensional Thermoformability Index (aDTI) at 105° C. of less than 15.

A thermoformable film comprises a polyethylene composition. The polyethylene composition comprises a first polyethylene which is an ethylene copolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution M.sub.w/M.sub.n of <2.3, a second polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 15,000 to 100,000 and a molecular weight distribution M.sub.w/M.sub.n of <2.3, and a third polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution M.sub.w/M.sub.n of >2.3, where the first polyethylene has more short chain branching than the second polyethylene or the third polyethylene. The polyethylene composition has a melt flow ratio (I.sub.21/I.sub.2) of ≤50 and an area Dimensional Thermoformability Index (aDTI) at 105° C. of less than 15.

Propylene is polymerised in the presence of a polymerisation catalyst comprising a solid catalyst component, an organoaluminium compound and an external electron donor, the process comprising the steps of (i) contacting propylene and hydrogen with the polymerisation catalyst in polymerisation conditions in a polymerisation reactor to produce a polymer of propylene; (ii) recovering the polymer of propylene from the polymerisation reactor; wherein the polymer of propylene has MFR of from more than 100 to 10000 g/10 min. The solid catalyst component comprises titanium, magnesium, halogen and an internal electron donor, characterised in that the internal electron donor is a compound according to formula (I) with R.sub.1 and R.sub.2 being the same or different and being a linear or branched C.sub.1-C.sub.12-alkyl group, and with R being H or a linear, branched or cyclic C.sub.1 to C.sub.12-alkyl, whereby it is preferred that R is not H. The external electron donor is a silane compound having the formula Si(OR.sup.11).sub.nR.sup.10.sub.4-n, wherein each R.sup.10 is independently a linear or branched C.sub.1-C.sub.4 alkyl, preferably methyl or ethyl; and each R.sup.10 is independently a linear or branched alkyl group having from 1 to 24 and optionally containing an atom of group 15 of periodic table of elements or comprises a cyclic group having from 6 to 12 carbon atoms.

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Propylene is polymerised in the presence of a polymerisation catalyst comprising a solid catalyst component, an organoaluminium compound and an external electron donor, the process comprising the steps of (i) contacting propylene and hydrogen with the polymerisation catalyst in polymerisation conditions in a polymerisation reactor to produce a polymer of propylene; (ii) recovering the polymer of propylene from the polymerisation reactor; wherein the polymer of propylene has MFR of from more than 100 to 10000 g/10 min. The solid catalyst component comprises titanium, magnesium, halogen and an internal electron donor, characterised in that the internal electron donor is a compound according to formula (I) with R.sub.1 and R.sub.2 being the same or different and being a linear or branched C.sub.1-C.sub.12-alkyl group, and with R being H or a linear, branched or cyclic C.sub.1 to C.sub.12-alkyl, whereby it is preferred that R is not H. The external electron donor is a silane compound having the formula Si(OR.sup.11).sub.nR.sup.10.sub.4-n, wherein each R.sup.10 is independently a linear or branched C.sub.1-C.sub.4 alkyl, preferably methyl or ethyl; and each R.sup.10 is independently a linear or branched alkyl group having from 1 to 24 and optionally containing an atom of group 15 of periodic table of elements or comprises a cyclic group having from 6 to 12 carbon atoms.

##STR00001##

The present invention relates to novel organo-magnesium compounds obtained by reaction of dialkyl-magnesium compounds and carbodiimides and their use as precursors for the preparation of further magnesium compounds and catalysts.

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 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 multimodal polyethylene copolymer suitable for use in cable insulation comprising: (III) 45 to 55 wt % of a lower molecular weight component which is an ethylene copolymer of ethylene and at least one C3-12 alpha olefin comonomer, said LMW component having a density of 940 to 962 kg/m.sup.3 and an MFR.sub.2 of 50 to 500 g/10 min; (IV) 55 to 45 wt % of a higher molecular weight ethylene copolymer component of ethylene and at least one C3-12 alpha olefin comonomer;

wherein said multimodal polyethylene copolymer has a density of 940 to 950 kg/m.sup.3, an MFR.sub.2 of 0.05 to 2.0 g/10 min and preferably at least one of crystallization half time>3.0 mins at 120.5° C., a crystallization half time>5.0 mins at 121° C. or a crystallization half time>10.0 mins at 122° C.

A multimodal polyethylene copolymer suitable for use in cable insulation comprising: (III) 45 to 55 wt % of a lower molecular weight component which is an ethylene copolymer of ethylene and at least one C3-12 alpha olefin comonomer, said LMW component having a density of 940 to 962 kg/m.sup.3 and an MFR.sub.2 of 50 to 500 g/10 min; (IV) 55 to 45 wt % of a higher molecular weight ethylene copolymer component of ethylene and at least one C3-12 alpha olefin comonomer;

wherein said multimodal polyethylene copolymer has a density of 940 to 950 kg/m.sup.3, an MFR.sub.2 of 0.05 to 2.0 g/10 min and preferably at least one of crystallization half time>3.0 mins at 120.5° C., a crystallization half time>5.0 mins at 121° C. or a crystallization half time>10.0 mins at 122° C.

The invention is directed to a polyethylene composition comprising 20-90 wt % of a LLDPE A and 80-10 wt % of a LLDPE B, wherein i) LLDPE A is obtainable by a process for producing a copolymer of ethylene and another α-olefin in the presence of an Advanced Ziegler-Natta catalyst, ii) LLDPE B is obtainable by a process for producing a copolymer of ethylene and another α-olefin in the presence of a metallocene catalyst.