초록 ▼

A method of forming a substantially encapsulating layer of a heat shrinkable polyolefin plastic on a glass container in which the neck, shoulder and body onto the bearing bottom surface of the container is covered. The body of the container is substantially greater in diameter compared with the neck

A method of forming a substantially encapsulating layer of a heat shrinkable polyolefin plastic on a glass container in which the neck, shoulder and body onto the bearing bottom surface of the container is covered. The body of the container is substantially greater in diameter compared with the neck. A cylindrical sleeve of the 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. Upon application of heat in the oven, 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 invention includes 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, heat shrinkable foam polyethylene sleeve material on the order of 4-5 inch diameter sleeve (bottle body diameter 4-5 inch and neck diameter 1-2 inch) and 14-15 mil thickness which is pre-oriented in machine direction (sleeve circumference) 60-80% and cross dimension 0-15% shrinks evenly and suitably onto the neck with good upper marginal control at a bottle rotation in the range of 150-300 RPM while immersed in the heat atmosphere of the oven at a production rate of approximately 100-250 BPM.

대표청구항 ▼

The method of shrinking a heat shrinkable plastic sleeve form onto a container, said container having a major diameter body portion and one or more substantially smaller portions of minor diameter including a finish portion defining a mouth opening to the container, comprising the steps of providing

The method of shrinking a heat shrinkable plastic sleeve form onto a container, said container having a major diameter body portion and one or more substantially smaller portions of minor diameter including a finish portion defining a mouth opening to the container, comprising the steps of providing containers in upright position at a loading sTation, grasping the containers by their upper finish portions at the loading station by a chuck device carried on a conveyor, moving the conveyor past a source of sleeves slightly larger in size than the major diameter of the container and made of a polyolefin plastic material that is pre-oriented circumferentially at least for 30% or greater shrinkage upon heating, assembling a sleeve of said material axially over the container, the sleeve being of a height dimension so as to extend from adjacent the finish portion of the container to adjacent the other end thereof, conveying the container and sleeve in an oven maintained at elevated temperature sufficient to shrink said material of the sleeve onto the container, rotating the container and sleeve about their central axis while in the oven at a rate of rotation that is sufficient to generate a centrifugal force component on the sleeve so as to maintain the plastic of the sleeve overlying said minor diameter portions of the container erect and billowed out for a time while the portion of said sleeve adjacent the major diameter portion of the container is shrunken thereon, and thereafter shrinking the balance of the sleeve onto the adjacent minor diameter portions of the rotating container so as to wrap the container below the finish portion thereof with a snug fitting conforming covering of the plastic on the exterior of the container.