| 摘要 |
A method of making a gas-permeable liquid-impermeable membrane includes the steps of perforating a film of linear low density polyethylene (or other suitable polyolefin) in such a way as to yield an array of holes each having an average diameter of approximately 350 , and then solution coating the needle d film with a porous polyurethane material having pores of a pore size of 1 to . Such a film is advantageously embodied in an ileostomy bag, and is fixe d to a bag wall thereof in a location to prevent faecal material contacting th e ~ bag filter, by a heat or RF wedding operation by which the polyolefin is welded to the bag wall which carries the filter. In use, the polyurethane is expose d to the bag contents, and permits gases to pass but prevents any liquid reaching the filter. |
