Patent ID: 7683141

Claim:
A polymer film comprising a propylene random copolymer which was produced according to a process comprising polymerisation of propylene with a comonomer, said comonomer being ethylene or an α-olefin comprising at least four carbon atoms, in the presence of a catalyst in a multistage process comprising polymerisation of propylene with a comonomer in a first reaction zone including at least one slurry reactor to give a first polymerisation product, transferring said first product to a second reaction zone including at least one gas phase reactor and polymerisation of propylene with a comonomer in said gas phase reactor in the presence of said first polymerisation product, wherein the temperature in the gas phase reactor is at least 10° higher than that in the slurry reactor, wherein the polymer has a multimodal comonomer distribution, wherein the content of xylene solubles in the polymer film is from 4 to 15 wt %, and wherein the film has a relative reduction of the static friction value (inside-inside) from one to four days of 35% or more, 40% or more.