Polypropylene based film

1 . An unoriented cast film, unoriented roll-stack film or unoriented blown film comprising a polypropylene composition comprising a random copolymer of propylene monomer units and ethylene comonomer units, wherein:

the random copolymer has a content of ethylene comonomer units of from 0.5 to 4.0 wt %, based on the total weight amount of monomer units in the random copolymer, and a sum of 2,1- and 3,1-regio defects of from 0.10 to 1.40 mol %, determined by 13 C-NMR spectroscopy,

the polypropylene composition has a melt flow rate MFR 2 of from 0.5 to 20.0 g/10 min, determined according to ISO 1133 at a temperature of 230° C. and a load of 2.16 kg, a melting temperature Tm of from 122 to 150° C., and a crystallization temperature Tc of from 90 to less than 115° C., and

the unoriented film has a tensile modulus in machine direction TM-MD in the range of from 450 to 850 MPa, when measured according to ISO 527-3 on a 50 μm monolayer cast film, a tensile modulus in transverse direction TM-TD of from 450 to 850 MPa, when measured according to ISO 527-3 on a 50 μm monolayer cast film, a haze of from 0 to 2.5%, when measured according to ASTM D 1003 on a 50 μm monolayer cast film, a sealing initiation temperature SIT of from 105 to 120° C., when measured on a 50 μm monolayer cast film, a coefficient of friction at 7 days CoF@7 days of 0.01 to 0.30, when measured according to DIN 53 375 on a 50 μm monolayer cast film, a hot tack force HTF of from 1.5 to 5.0 N, when measured according to ASTM F 1921-98 (2004), method B on a 50 μm monolayer cast film, and a protrusion impact of from 30.0 to 125.0 N, when measured according to ASTM D5748 on a 50 μm monolayer cast film.

2 . The film according to claim 1 , wherein the polypropylene composition comprises an alpha-nucleating agent.

3 . A process for producing a film according to claim 1 comprising:

a) Polymerizing the random copolymer of propylene monomer units and ethylene comonomer units in the presence of a single site catalyst system;

b) Preparing the polypropylene composition; and

c) Preparing the film.

4 . The process according to claim 3 , wherein the film is an unoriented film and prepared by cast film or blown film extrusion.

5 . The process according to claim 3 , wherein the random copolymer is polymerized to have a melt flow rate MFR 2 of from 0.5 to 3.5 g/10 min, determined according to ISO 1133 at a temperature of 230° C. and a load of 2.16 kg and then vis-broken to a melt flow rate MFR 2 of from 5.5 to 20.0 g/10 min, determined according to ISO 1133 at a temperature of 230° C. and a load of 2.16 kg.

6 . The process according to claim 4 , wherein the single site catalyst system comprises:

(i) a metallocene catalyst selected from rac-dimethylsilanediylbis [2-methyl-4-(3′,5′-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl [2-methyl-4-(4′-tert-butylphenyl)-inden-1-yl] [2-methyl-4-(4′-tertbutylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl [2-methyl-4-(4′-tert-butylphenyl)-inden-1-yl] [2-methyl-4-phenyl-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl 2-methyl-4-(3′,5′-tert-butylphenyl)-1,5,6,7-tetrahydro-sindacen-1-yl] [2-methyl-4-(3′,5′-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl [2-methyl-4,8-bis-(4′-tert-butylphenyl)-1,5,6,7-tetrahydro-sindacen-1-yl][2-methyl-4-(3′,5′-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl [2-methyl-4,8-bis-(3′,5′-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen-1-yl] [2-methyl-4-(3′,5′-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl [2-methyl-4,8-bis-(3′,5′-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen-1-yl] [2-methyl-4-(3′,5′-5 butyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride ditert-

and

(iii) a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst.

7 . The film according to claim 2 , wherein the polypropylene composition comprises a polymeric alpha-nucleating agent.