Apparatus for stretching a web of material

摘要

A process for longitudinally stretching a polymeric film having thickened longitudinal edges while the film is constrained in the lateral dimension by a plurality of successive pairs of grippers, the improvement comprising first guiding the film with a first group of gripper pairs having a predetermined clearance therebetween; and then gripping the film with a second group of gripper pairs with a predetermined amount of force. An apparatus for use in the process is also disclosed.