Packaging industry relies upon wrapping as a means of securing goods on pallets for transport. However, wrapping may have different implications depending upon the products to be shipped. In general, there are two types of wrapping operations, namely stretch wrapping and shrink wrapping. Each operation differs in terms of application, purpose and equipment.
A stretch wrap is made of polyethylene, while a stretch wrap is made of polyolefin, which is a specific type of polythene. A stretch wrap is tightly wrapped around palleted goods, in a way that the film is stretched by 200-300% of its original length. Once it is wrapped, it tends to regain its original shape, due to which it holds the objects tightly. In contrast, a shrink film is wrapped loosely around the products following which heat is applied to the film. This results in shrinkage of the film, causing the product to be securely wrapped.
These processes also require different types of equipment. For stretch wrapping, there are hand tools and manual, semi-automatic and fully automatic machines that perform varying degrees of this operation. On the other hand, shrink wrapping machines require a film and a heat gun to accomplish wrapping. For more automation, heat tunnels can also be installed.
Apart from this, the purpose of wrapping is also different for stretch and shrink wrapping. Stretch wrapping is usually done for bundling small articles together for transit, while shrink wrapping is more suitable for packing individual food, pharmaceutical and cosmetic products. It is the better option when the objective is to put products on display. It is important to understand that each type of film used is specific to its purpose. A shrink film does not have the ability to stretch beyond its original length, while a stretch film cannot heat treated to achieve contraction.