Stretch film is widely used in various industries. Almost everyone knows what it looks like, but probably nobody wondered what it was made of. What is the reason for their tensile properties, so useful in various logistics activities?
What is stretch film made of and what does it mean in terms of properties?
Stretch wrap is made almost entirely of the raw material known as LDPE, which is short for linear low density polyethylene. It is thanks to this raw material that the final product will be characterized above all by great flexibility, but also by thermo-plasticity and a kind of adhesion. However, depending on the specific needs, the composition of the stretch film may differ. Manufacturers sometimes fortify them with various types of mixtures of other ingredients. They can highlight certain properties that will be extremely useful in a given industry. These characteristics can be, for example, greater extensibility or resistance or even puncture resistance of the material.
The differentiation can also depend on the color plane. In a situation where it is necessary to wrap a pallet of products in a supermarket, a transparent sheet with high flexibility will be good, which will allow safe packaging of products, but you will always know what is on the pallet. . In turn, the black sheet will work anywhere the packaged item should not be visible. One of the most common uses is to wrap parcels at the post office for protection.
The individual films may also differ in terms of thickness, flexibility or resistance to mechanical aspects. Depending on the specific model, different thermal insulation properties or even resistance to ultraviolet rays may also appear.
Two Main Methods of Stretch Film Production
Depending on the film manufacturer, the production method may differ. However, there are two main methods of producing stretch film. These techniques are: “blown” and CAST.
Thanks to this technique, the final product has very good quality, including high resistance to various types of puncture, as well as other mechanical damage. In addition, the sticking effects of the material during use are very good, which allows for even more effective packaging. This technology is based on melting the resin and blowing it in both directions, transverse and machine. The last step is to cool the assembly with air. Thanks to all these activities, the final effect results in a high extensibility of the film, which is also extremely durable.
The CAST method is much faster than the kick technique. This results in high profits at the production stage, which is why it is sold at a much lower price. In addition, manufacturers often add various types of additives or colorants to it, which will allow various types of properties. Its production is based on casting molten resin into a specialized shape. It is then stretched by machine to obtain the desired material properties. Extruders are responsible for the cooling process. This method makes the sheet very durable and flexible, as well as having great resistance to puncturing or tearing.
The most common use of stretch film
The composition of stretch film is already clear, but what exactly is it used for and why is it so popular? Stretch film, thanks to its many properties, is used in various industries. However, it is most popular in transport, logistics and the food industry. Farmers and traders are also happy to use it. It is an extremely economical solution that makes it possible to secure, protect or simply pack different types of goods.
The films that can be found on the market are: machine, jumbo and manual stretch. The former is used for automated wrapping and palletizing, while the latter will be extremely useful for packaging. The last will be used for manual wrapping, which will also be used at home.