Method of forming an integral closure for a thermoplastic container

摘要

An improved high speed cast process for fusing fasteners, with strips of film at their base, to separately extruded film or sheet stock for making containers with integral closure means. The process makes available multiple sets of male and female fastener elements, with variable spacing, in a single extrusion operation. The apparatus is configured so that adhesion between the fastener elements and the film or sheet occurs very close to the die lips before significant cooling of the extrudate occurs. Containers with improved profiles are obtained because the base permits the profiles to remain relatively rigid during closing and opening.