A BAG OR POUCH FOR CONTAINING A FLUID

摘要

A bag or pouch is made from a pair of plastic film sheets which are sealingly interconnected so as to define a storage chamber (14, 15) for containing a fluid. The storage chamber communicates with a fluid discharge passage (17). The material of at least one of opposite parts of the film sheets defining the discharge passage (17) or other parts of the bag closely adjacent to the discharge passage has been modified so as to cause the opposite sheet parts to tend to move into mutual sealing contact when the discharge passage upstream thereof is distended by fluid contained in the bag or pouch. The sheet material may, for example, be modified by exposing the material to a treatment so as to modify at least one characteristic thereof. Thus, the sheet material may be locally modified by heating, cooling, radiation, exposure to one or more chemical substances, shrinking, and/or by mechanical treatment.