METHOD OF MAKING FRANGIBLE SEAL

摘要

A method is provided for forming a fracturable seal of the type wherein a plastic cup-shaped closure is hermetically sealed to a plastic planar surface, such as the neck of pharmaceutical solution containers. The seal is formed with the closure by forcing a die heated above the melting point of the plastic material into the planar surface, with the sealing die also being in heat exchange relationship with a portion of the closure. Both the planar surface and the closure adjacent thereto become molten and the surface material is displaced to form a fused seal transverse to the surface. The surface is depressed at least 0.005 inch from its original height by the sealing action of the die, and a frangible section is formed in the vertical side wall of the depression. The seal will be fractured due to tension stress when the closure is removed from the surface.