POROUS FILM

摘要

A method of producing a porous film comprises subjecting a fibrous material comprised of fibres of a film-forming material to conditions of heat and pressure to convert the fibrous material to a porous film. The method allows the production of film material having substantially uniform pore sizes. For example, the pore size distribution of the film may be such as to have a ratio of maximum pore size: mean flow pore of less than 1.2, e.g. less than 1.1.