Strapping – What is it Used For?
The most commonly used packaging strategy is known as strapping or also called bundling. This process is normally done by applying a strap to an item like a box or a palette to combine, hold, fasten and to reinforce stability and also helps to protect shipping and avoids shifting of the items during transportation. The strap itself is a flat but flexible material most commonly made from different plastics. Depending on what kind of items and products strapping is applied, there are different advantages for different materials being used as strap. Paper strap is used for securing paper products between industrial processes for example as the need to cut the strap is not necessary and can be removed fast and easily during the flow of the production process. The strongest material to be used for strapping is steel – it is also the oldest method known. Steel is normally ideal for extreme duty holding like in the construction industry where heavy items need to be moved efficiently. The strap out of steel is often coated and has a surface finish of wax or paint to even out the tension around the objects that need strapping.
Mostly used and known is plastic strap – mostly polypropylene and polymer variations. It is mostly used for strapping palettes, has often embossed or printed messages like company logos on it and is ideal for the light to medium duty. It offers very good elongation at break, however this material tends to have “dead stretch” under extended stress which is then beyond repair. Polyester is more used when you need a near-steel strength as it has the strongest plastic characteristics. In cold climates a strap bonded in hot melt glue is the ideal support for transportation as it is extremely weather-proof then. Polyester shows better strength and does not tend to material fatigue in comparison to strapping with polypropylene based strap. The best and most specific strength has Nylon but it is very expensive and has been replaced over time by polyester. It is mostly used when material is constantly stored in cold rooms as it deals also best with ongoing low temperature.
The last version used is woven and corded strapping and normally consist of polyester and rayon (which is a manufactured regenerated cellulose fibre, a semi-synthetic fibre, also known as viscose). When you are using this kind of material you will however require a buckle for doing the joints. The advantage is that it has a larger system strength than steel and makes it ideal for rail shipments and sea transportation as the strapping has an “memory” effect and stays the same over a very long period of time.
Strapping materials are joined in different ways – after the strap is tensioned the strap is often sealed to itself with the help of melting the plastics together with hot knife systems. Thicker plastics use systems where the plastic material is pressed together in addition to pure heating and literally forces the material to be joined by building friction with teeth shaped tools. Steel strap is sealed with a nothc joint and a seal, a seal and crimp or via welding.
Copyright (c) 2010 Daren Paul Burbridge