Abstract: A process of expanding plastics film is disclosed, together with an apparatus for performing that process, in which expansion of the plastics film is performed under the control of a liquid providing a stable hydraulic mass, by the downward extrusion and drawing of the plastics film, and the final expansion thereof, exclusively under the influence of the static and dynamic pressure of a hydraulic mass, at a position spaced downwardly of the extrusion head, the hydraulic mass being one that remains in a liquid phase at all temperatures encountered during the step of lateral stretching of the plastics film, to the exclusion of vaporization of the hydraulic mass.

Abstract: Flat open ended plastic bags having at transverse piercing adjacent their open ends to provide a tear strip. The bags are stacked with their open ends in alignment and then the stack folded end for end so that the closed ends of the bags are slightly short of the transverse tear strips. The folded bag assembly is then folded transversely and the twice folded assembly introduced, tear strips first, in the open end of a package which may be another plastic bag. The enclosing plastic bag and the tear strips therein are then secured together by a transverse welding. The open end of the enclosing bag may then closed. Preferably the enclosing bag also has transverse piercing adjacent its open end to provide another tear strip. Thus when the closed end of the bag is torn off by its tear strip, the bags in the package may be removed, one by one, by tearing them from their strips without disturbing the remaining bags in the package.