Flexible packaging boxes of non-shrinkable plastics - which are sealed strengthed by shrinking plastic sleeve over body cover base parts

摘要

Flexible packaging boxes consisting of non-shrinkable plastic material are strengthened and sealed by (a) fixing the base part onto the cylindrical or oral body of plastic sheet, (b) filling the body with the material to be packaged; (c) fixing the cover on the body; (d) pulling over the box a sleeve of shrinkable thermoplastic material, this sleeve having a slightly greater diameter than the cover and base part, and a greater length than the total distance separating the external walls of these parts; and (d) thermally shrinking the sleeve in an oven, so that it adapts exactly to the contours of the box, and closes over the cover and base part. Provides an excellent seal, and considerably increases the strength/rigidity of the packaging box. The body of the box is resistant to impacts and bursting, even when made of thin plastic sheet.