Shrink wrap, also shrinkwrap or shrink film, is a material made up of polymer plastic film. When heat is applied it shrinks tightly over whatever it is covering. Heat can be applied with a hand held heat gun (electric or gas) or the product and film can pass through a heat tunnel on a conveyor. Shrink wrap is commonly used as an overwrap on many types of packaging, including cartons, boxes, beverage cans and pallet loads. A variety of products may be enclosed in shrink wrap to stabilize the products, unitize them, keep them clean or add tamper resistance. It can be the primary covering for some foods such as cheese and meats. It is also used to cover boats after manufacture and for winter storage. Heat-shrink tubing is used to seal electric wiring.
Shrink bands are applied over parts of packages for tamper resistance or labels. It can also combine two packages or parts. A shrink film can be made to shrink in one direction (unidirectional or mono-directional) or in both directions (bidirectional). Films are stretched when they are warm to orient the molecules from their initial random pattern. Cooling the film sets the film's characteristics until it is reheated: this causes it to shrink back toward its initial dimensions.
Prior to orientation, the molecules of a sheet or tube are randomly intertwined like a bowl of spaghetti. The molecules are coiled and twisted and have no particular alignment. However when a draw force is imposed, the amorphous regions of the chains are straightened and aligned to the direction of orientation. By applying proper cooling, the molecules will be frozen in this state until sufficient heat energy is applied to allow the chains to shrink back. One can visualize this phenomenon by stretching a rubber band and dipping it into liquid nitrogen so as to freeze in the stretched state. The band will remain in this state as long as it is kept at sufficiently cold temperatures. However, when enough heat energy is applied, the rubber band will shrink back to its original relaxed state.
8 Advantages of Shrink Wrapping You Should Know:
When heat is applied to shrink wrap, it creates a very tight seal which fully protects the items’ contents. Once sealed, the items are protected from damages which can be caused by dust, dirt or moisture. Some types of shrink wrap even come with a UV protection feature, to keep products safe from the sun’s harmful rays.
Shrink wrap is made from a very sturdy, durable plastic. It is difficult to tear or puncture. Unlike other materials, shrink wrap does not become brittle or weaken when it is under extreme weather conditions and it does not loosen nor sag, ensuring more security.
Tampering will be avoided:
Any tampering will be noticeable immediately and for this reason, many pharmaceutical companies and food manufacturers now shrink wrap their products to ensure that items are or were delivered with the level of diligence required. Other banks and government agencies use a special type of shrink wrap which changes color when the material has been stretched or meddled – this is to show if there has been any unauthorized activity which transpired with the storage or transfer of said items.
Shrink wrapping is an affordable option for it only requires two things, as mentioned – heat and plastic. The price may vary on the type of plastic used, but even considering such the process is cheaper than the value it delivers.
It is designed to maximize space as it keeps bundled items close together without the use of additional bulky materials such as boxes. And when space is maximized, value for money is saved especially for storage and transport.
Helps in Branding:
An added feature of shrink wrap is that it can be designed with colors, words, pictures and logos that will help promote products. From the production floor until it reaches the end user, the product carries with it the company’s logo. This is a marketing tool that can increase brand awareness, and make a brand more visible to potential customers.
Assist in the Longevity of Perishable Goods:
Food is easily perishable and because of this, manufacturers are posed with a challenge to extend their products’ shelf life. Food-grade shrink wrap is a regular choice for food production companies as exposure to external factors may cause the spoilage faster which will entail waste for food companies and this exposure is being avoided by the careful sealing of each food item.
Shrink wrapping is not limited by the size of the item to be wrapped. Small electrical wires are often shrink wrapped to prevent exposure to moisture, as well as game pieces, candies, and other hardware. On the other hand, shrink wrap kits are sold to weatherize boats and greenhouses even freight on trailers and trains can be shrink wrapped for easier transport. To extend the capabilities of shrink wrap, advanced systems can even shrink wrap entire buildings to prevent chemical leaks or exposure from hazardous materials.