Apparatus controlling shrinkage of a sleeve wrap on a container

摘要

An apparatus for forming a smooth, even, substantially encapsulating layer of a heat shrinkable polyolefin plastic on a glass container. The body of the container is substantially greater in diameter compared with the neck. A cylindrical sleeve of polyolefin is telescopically placed along the outer surface of the container and the two are conveyed together into a heating oven for shrinking the sleeve snugly over the container. During heating, the polyolefin initially softens and becomes limp such that the sleeve tends to fold over or upon shrinking creates wavy top margins on the shrunken covering. The apparatus provides controlled rotation of the bottle and sleeve in the oven to apply a centrifugal force to the limp plastic which remains erect and billowed outwardly to give the material time to react with the heat such that the sleeve material shrinks into overall even, snug contact about the contour of the container without folds and wrinkles. By way of example, using 14-15 mil foam polyethylene sleeve on the order of 4-5 inch diameter over a bottle having a body diameter 4-5 inch and neck diameter 1-2 inch, the foam being pre-oriented in machine direction (sleeve circumference) 60- 80% and cross dimension 0-15% is subjected to a bottle rotation in the range of 150-300 RPM while immersed in the oven heated by hot air at a ware production rate (speed) of 100-250 BPM.