Apparatus and process for producing cold seal in plastic bags

Abstract

A process of cold sealing two layers of plastic film material together is used as part of the structural element of a plastic bag made from plastic film. The bag has a closed bottom, a continuous closed periphery, and an open top. The improvement provides the bag with a cold seal, which cold seal does not form a part of the closed bottom and continuous closed periphery of the bag. In the improved process, it is required that the first and second plastic films of the bag be confronted to one another in a disposition for sealing. Compression dies are provided on at least one side of the juxtaposed first and second plastic films, the compression dies are provided with the size and shape of the cold seal desired. Impressing of the compression dies across the juxtaposed first and second plastic films occurs. This impressing is at a temperature and pressure sufficient to fuse the first and second plastic films together. However, the impressing has insufficient temperature and pressure to permanently fuse the first and second plastic films together so that the films when separated at the cold seal each retain structural integrity. Embodiments are set forth where the cold seal is used as a structural element to square out square bottom bags. Specifically, the cold seal is provided with at least a linear disposition which imparts to the cold seal the predisposition to fold or hinge at the boundary to cause opening to the square bottom shape.