Process for the production of a porous film having high bursting strength

摘要

Process for the production of a film having improved bursting strength by applying a recessed line pattern to a porous film produced from a solution of polyethene and from which the solvent has been removed, at a temperature below the melting point of the polyethene, and subsequently stretching the film biaxially with a degree of stretching of at least 2 x in each of the two directions, the surface area of the film increasing by at least a factor 8, and a porous film having high bursting strength.