abstract |
The invention relates to a biaxially orientated, single or multi-layered porous film made of propylene homopolymer and/or propylene blockcopolymer and .beta.- nucleation agent. Said film has a Gurley value of between 50 to <400s and shrinkage in the longitudinal direction of <5% at 100 C/1 hour, and a transverse shrinkage of <10% at 100°C/1 hour. |