| 摘要 |
<p>A method of making a gas-permeable liquid-impermeable membrane includes the steps of perforating a film (10) of linear low density polyethylene (or other suitable polyolefin) in such a way as to yield an array of holes (12) each having an average diameter of approximately 350 mu (microns), and then solution coating the needled film with a porous polyurethane material (14) having pores of a pore size of 1 to 10 mu . Such a film is advantageously embodied in an ileostomy bag, and is fixed to a bag wall thereof in a location to prevent faecal material contacting the bag filter, by a heat or RF welding operation by which the polyolefin is welded to the bag wall which carries the filter. In use, the polyurethane is exposed to the bag contents, and permits gases to pass but prevents any liquid reaching the filter. <IMAGE></p> |
