Process and apparatus for cutting and sealing multiple plies of thermoplastic material having thickened sections

Abstract From the Canadian patent

A process and apparatus is provided for cutting multiple plies of thermoplastic material having thickened sections, such as defined by cross-sections of matable parts of a zipper closure formed in the material and for, concurrently sealing the severed margins of the material which includes sealing the severed zipper closure portions thereof. The process and apparatus perform the operative steps of: first, preblocking the thickened material adjacent to the zipper closure portions of the material in areas thereof to be severed and sealed; then applying heat and pressure to the thickened material and remaining sections of the material in those areas to render the material tacky and temporarily …