Method for thickening at least one edge of plastic sheeting

摘要

A method for creating a thickened bead (8) along at least one edge of a plastic film (2) involves passing the film through a cooling and guiding tool (3) with an exposed edge passing over a heater (4). Claimed process equipment includes the cooling and guiding tool (3) and a heater (4, 5) underneath whose upper face (5) rises towards the lower face of the cooling and guiding apparatus (3) where the bead (8) is produced. A film (2A) produced by the process has an thickened bead (8) along one edge or comprises a loop with the two edges welded together and a thickened bead formed at the end. In both cases the film and bead are of the same material. A use of the film in dentistry is claimed, the film consisting of thin strips or being cut into thin strips.