A sterilizable medical packaging with living pores according to this invention is made of a specific blend of polyolefin polymers and additives wherein during the production process, the mixture is extruded to form a fine heterophasic substrate film comprising a rigid tough phase of a very fine crystalline lattice network which contributes to the strengthening and toughening of the film substrate, and a soft elastic phase of dispersing amorphous domains which fulfills the crystalline network thoroughly. Under pressure in sterilization process, these amorphous regions will enlarge their interstitial volumes, enabling the sub-micrometer pores to allow for gas phase sterilant to permeate through the packaging to sterilize the medical products inside, and these living pores will close automatically when the packaging is removed from the sterile chambers into a common atmosphere. Without any open dead pore structure, but by having a balance set of heterophase structures and some hydrophilic additives, this novel packaging can undergo all common sterilization methods, especially by ethylene oxide or steam, so that the film is ideally used for sterile medical packaging with an excellent microbial barrier that distinctly ensure product's sterility and prolong its shelf life, even in a poor storage condition.
