Sealing a heat-shrinkable plastics material

摘要

A first sheet of heat-shrinkable plastics material is sealed to a second sheet, which may be of the same material, while the sheets are under tension. The sheets, which may be the sides of a bag, are moved in the general direction in which the seal is to be formed by a first pair of belts 2 while a region above the area to be sealed is moved by another pair of belts 12 which diverge from the direction of the first belts. The region in between is thereby placed under tension and is sealed using a hot air sealer as shown and/or a contact sealer (see Figures 4 and 5). The top portion may be separated and passed to a trim remover 34 through which an air flow passes to apply a suctional force to remove the waste material.