High shrink polyethylene films

A blown film comprising at least one layer formed of a polyethylene composition comprising a homogenous blend of a low density polyethylene with a metallocene-catalyzed polyethylene having a density of at least 0.906 g/cm3 and a Dow Rheology Index of at least 5/MI2, wherein MI2 is the melt index measured according to ASTMD-1238 condition 190° C./2.16 kg and the Dow Rheology Index being determined by a dynamic rheological analysis performed at 190°, said metallocene-catalyzed polyethylene being catalyzed with a catalyst system comprising a metallocene component and an activating agent selected from the group consisting of an alumoxane or an aluminum alkyl providing a mole ratio of aluminum to the transition metal of said metallocene component within the range of 50:1-300:1.

A process for the preparation of a blown film, forming said film in a blown film line from a polyethylene composition comprising a homogenous blend of a low density polyethylene with a metallocene-catalyzed polyethylene having a density of at least 0.906 g/cm3 and a Dow Rheology Index of at least 5/MI2, wherein MI2 is the melt index measured according to ASTMD-1238 condition 190° C./2.16 kg and the Dow Rheology Index being determined by a dynamic rheological analysis performed at 190°, said metallocene-catalyzed polyethylene being catalyzed with a catalyst system comprising a metallocene component and an activating agent selected from the group consisting of an alumoxane or an aluminum alkyl providing a mole ratio of aluminum to the transition metal of said metallocene component within the range of 50:1-300:1, said film being characterized by:

• a cohesion force in the transverse direction at room temperature of at least 5% greater than the cohesion force in the transverse direction of a corresponding biaxially-oriented film formed of said low density polyethylene in a pure form;
• and
• a gloss at an angle of 45° of at least 60 and a haze of less than 10% while keeping a good rigidity.

A biaxially-oriented film which has been oriented in the machine direction and the transverse direction, formed from a homogenous blend of a polyethylene composition comprising a homogenous blend of a low density polyethylene with a metallocene-catalyzed polyethylene having a density of at least 0.906 g/cm3 and a Dow Rheology Index of at least 5/MI2, wherein MI2 is the melt index measured according to ASTMD-1238 condition 190° C./2.16 kg and the Dow Rheology Index being determined by a dynamic rheological analysis performed at 190°, said metallocene-catalyzed polyethylene being catalyzed with a catalyst system comprising a metallocene component and an activating agent selected from the group consisting of an alumoxane or an aluminum alkyl providing a mole ratio of aluminum to the transition metal of said metallocene component within the range of 50:1-300:1, said film having a cohesion force in the transverse direction which is greater than the cohesion force in the transverse direction of a corresponding biaxially-oriented film formed of said low density polyethylene in a pure form.

THe biaxially-oriented film of calim 19, wherein said film has a cohesion force in the machine direction which is greater than the cohesion force in the machine direction of the corresponding film formed of said low density polyethylene in a pure form.