Porous film and preparation process thereof

摘要

A porous film is obtainable by uniaxially or biaxially stretching a film formed from a resin composition containing 25 to 70 parts by weight of a polyolefin resin and 75 to 30 parts by weight of an inorganic filler, the composition further containing 0.5 to 10 parts by weight of dehydrated castor oil (a) and 0.01 to 5 parts by weight of hardened castor oil (b) based on the total 100 parts by weight of the polyolefin resin and the inorganic filler; and the amount of the component (a) being 20 to 95% by weight based on the total amount of the components (a) and (b). The resulting porous film has the softness and feel like cloth, good moisture vapor transmission and good uniformity of film thickness. Furthermore, adhesive strength e.g. of the bond between a pressure-sensitive adhesive tape to the film does not deteriorate, because the oil components (a) and (b) do not migrate to the surface of the porous film, so it can be used as materials of articles such as disposable diapers fixable and attachable by adhesive securing tapes.