Composite container with membrane and bead closure system

摘要

A composite container of paperboard has a polymeric film barrier layer on the inner surface thereof. A rolled bead is formed at a top end of the container and a membrane closure is bonded to the bead by a first heat seal material on the bead and a second heat seal material on the membrane. The heat seal materials preferably comprise ethylene acid copolymer such as methacrylic acid or acrylic acid, partially neutralized with zinc or sodium ions. A primer layer is disposed between the heat seal material on the bead and the polymer barrier layer of the container. The primer provides a high z-direction bond strength but is designed to fail in a shear tearing mode when peeling the membrane from the bead, such that the heat seal material on the bead is detached from the bead and remains attached to the membrane. The primer prevents tearing of the polymer barrier layer of the container.