Abstract: An unstretched first plastic foil is laminated with a longitudinally stretched second plastic foil by the application of heat and pressure. The second foil is preheated, thereupon stretched and thereafter tempered prior to being laminated with the first foil which is heated prior to lamination. The laminating step can coincide with the tempering step and immediately follows the stretching step so that the laminating step can be carried out by utilizing heat which is required for stretching of the second foil. The material of the first foil is or can be identical with the material of the second foil; in any event, the two materials are sufficiently compatible to permit bonding of the unstretched foil to the stretched foil by the application of heat and pressure alone, i.e., without resorting to an adhesive.

Abstract: A container for storage of flowable media has a deformable fluidtight inner envelope, a deformable fluidtight outer envelope and a collapsible frame between the two envelopes. The frame has two mirror symmetrical sections which are pivotally connected to each other along two parallel first fold lines, and each section has two second fold lines which are parallel to the first fold lines and divide the respective section into a median panel and two outer panels. The median panels carry pivotable flaps at both ends, and each outer panel carries at its ends pivotable triangular reinforcing elements. The frame is made of cardboard and can be erected by exerting pressure against the outer sides of the first fold lines. This causes the panels of each section to pivot relative to each other along the second fold lines while the outer envelope folds the flaps. The flaps form the top and bottom end walls of the erected frame, and the reinforcing elements enhance the stability of the frame at its ends.