Tubular container with heat seal having an inner and outer bead and method of manufacturing said container

摘要

A method of manufacturing multi-ply tubular containers for food products is provided including the steps of applying an aqueous adhesive to a surface of a paperboard body ply and then heating the aqueous adhesive to evaporate part of the water content and render the adhesive substantially tacky. The body ply and a polymeric liner ply having a moisture barrier layer are then either fed to a shaping mandrel from opposite sides and bonded together as the container is formed on the mandrel or are first passed through a nip to adhere the liner ply to the body ply and then wrapped around the mandrel as a laminate to create the tubular container. Accordingly, an advantageous tubular container can be manufactured having a body ply formed of paperboard which is wrapped into a tubular shape to define an inner surface. The body ply defines a predetermined circumferential length before being wrapped which corresponds to one revolution of the body ply when wrapped in a tubular shape. A polymeric liner ply is adhered to the inner surface of the body ply and defines a circumferential length equal to that of the body ply prior to being wrapped. Accordingly, the liner ply is circumferentially compressed when the body ply is wrapped into the tubular shape and advantageously has a wrinkled surface finish after being wrapped which is caused by the circumferential compression of the liner ply. Another feature of the invention is a sealed composite container having an end seal formed by a pair of inner and outer beads of a heat flowable polymer forming a part of the liner and membrane-type lid.