Shrink wrap film supplies are used with shrink wrapping machines to bundle or package goods for distribution.
When shrink wrap film is stretched it becomes warm to the orientation of its molecules an initial random pattern. When shrink wrap film sets or cools the film stabilize until it is reheated: this causes it to shrink back toward its initial dimensions. A shrink film can be made to shrink in one direction or in two directions.
Orientation on a commercial scale can be achieved using either of two processes: a tenterframe or a bubble process.
Tenterframe technology is used to produce a variety of “heat-set” products, with BOPP being the most common (heat-setting is a process whereby a film is reheated in a constrained state such that the shrink properties are destroyed).
The second commercial process is the bubble process, sometimes referred to as the tubular process. In this process, a primary tube is produced by either blowing or casting the tube onto an external or internal mandrel, respectively. It is common to use water to help cool the primary tube at this point. After the primary tube has been cooled, it is then reheated and inflated into a second bubble using air much like a balloon is blown. Upon inflation, the tube is oriented in both directions simultaneously.
The family of shrink film supplies has broadened over the years with many multilayer constructions being sold today. Shrink film attributes include shrink, sealability, optics, toughness, and slip. With regard to shrink properties, there are onset temperature, free shrink, shrink force, shrink temperature range, memory, and overall package appearance.
Shrink wrap is also commonly used within more industrial applications using a heavier weight shrink film supplies. The principles remain the same with a heat shrinking process using a hand held heat gun. The following shrink wrap applications are becoming more widely used and accepted:
Industrial shrink wrap containment of large plant equipment/components
Scaffold wrap containment of buildings/bridges
Building temporary shrink wrap structures for storage or other business operational uses
Marine shrink wrapping of boats and other vehicles
Shrink wrapping of palletized freight
Disaster contingency and relief projects such as damaged buildings/roofs