Polyethylene Composition Suitable for the Preparation of Films and Process for Preparing the Same

Abstract

A polyethylene composition, in particular suitable for the preparation of films, and a process for preparing the same are described. The polyethylene composition of the invention comprises from 50 to 89% by weight of a first polyethylene component comprising at least one multimodal polyethylene including a plurality of ethylene polymer fractions having distinct molecular weights and comonomer contents, at least one of said plurality of ethylene polymer fractions being prepared by the use of a single site catalyst, and from 50 to 11% by weight of a second polyethylene component comprising a low or medium density polyethylene.

1 - 10 . (canceled) 
   
   
       11 . A polyethylene composition comprising: (a) from 50 to 89% by weight of a first polyethylene component comprising a multimodal polyethylene including a plurality of ethylene polymer fractions having distinct molecular weights and co-monomer contents, at least one of said plurality of ethylene polymer fractions being prepared by the use of a single site catalyst; and (b) from 50 to 11% by weight of a second polyethylene component comprising a low density polyethylene or a medium density polyethylene. 
   
   
       12 . The polyethylene composition of  claim 11  having a density of 0.915 to 0.955 g/cm 3 . 
   
   
       13 . The polyethylene composition of  claim 11 , wherein said first polyethylene component has a density of from 0.920 to 0.960 g/cm 3 . 
   
   
       14 . The polyethylene composition of  claim 11 , wherein said second polyethylene component has a density of from 0.910 to 0.940 g/cm 3 . 
   
   
       15 . The polyethylene composition of  claim 11 , wherein the first polyethylene component comprises a bimodal polyethylene including a low molecular weight ethylene homopolymer and a high molecular weight ethylene copolymer. 
   
   
       16 . The polyethylene composition of  claim 15  having a density of 0.915 to 0.955 g/cm 3 . 
   
   
       17 . The polyethylene composition of  claim 15 , wherein said first polyethylene component has a density of from 0.920 to 0.960 g/cm 3 . 
   
   
       18 . The polyethylene composition of  claim 15 , wherein said second component has a density of from 0.910 to 0.940 g/cm 3 . 
   
   
       19 . The polyethylene composition of  claim 15 , wherein said high molecular weight ethylene copolymer comprises 1 to 10% by weight of a comonomer selected from the group consisting of propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and 1-decene, and mixtures thereof. 
   
   
       20 . A process for producing a polyethylene composition, said process comprising: (a) subjecting ethylene, optionally with comonomer(s), to a plurality of polymerization stages, wherein at least one of the plurality of polymerization stages is carried out in the presence of a single site catalyst to prepare a multimodal first polyethylene component; (b) preparing a second polyethylene component comprising a low density polyethylene or a medium density polyethylene; and (c) combining said second polyethylene component and said multimodal first polyethylene component to obtain a polyethylene composition comprising from 50 to 89% by weight of the first polyethylene component and from 50 to 11% by weight of the second polyethylene component. 
   
   
       21 . The process of  claim 20 , wherein the single site catalyst comprise a metallocene. 
   
   
       22 . The process of  claim 20 , wherein the polyethylene composition has a density of 0.915 to 0.955 g/cm 3 . 
   
   
       23 . The process of  claim 20 , wherein said first polyethylene component has a density of from 0.920 to 0.960 g/cm 3 . 
   
   
       24 . The process of  claim 20 , wherein said second component has a density of from 0.910 to 0.940 g/cm 3 . 
   
   
       25 . The process of  claim 20 , wherein the first polyethylene component comprises a bimodal polyethylene including a low molecular weight ethylene homopolymer and a high molecular weight ethylene copolymer. 
   
   
       26 . A film comprising a polyethylene composition of  claim 11 . 
   
   
       27 . The film of  claim 26 , wherein the polyethylene composition has a density of 0.915 to 0.955 g/cm 3 . 
   
   
       28 . The film of  claim 26 , wherein said first polyethylene component has a density of from 0.920 to 0.960 g/cm 3 . 
   
   
       29 . The film of  claim 26 , wherein said second component has a density of from 0.910 to 0.940 g/cm 3 . 
   
   
       30 . The film of  claim 26 , wherein the first polyethylene component comprises a bimodal polyethylene including a low molecular weight ethylene homopolymer and a high molecular weight ethylene copolymer.