As a packaging material, stretch film is often commonly confused with shrink wrap; These two are different, however.
Stretch film is wrapped tightly around pallet loads, packages, or objects to secure them together or keep them protected. Shrink wrap, on the other hand, is applied by first covering the item loosely; heat is then used on the shrink wrap, causing it to shrink tightly around the package.
If what you need is to hold loads together for transportation or storage, stretch film packaging will be the best solution for you. On the other hand, if your priority is to protect or bundle small loads together, shrink wrap will work better. Shrink wrap is also widely used for covering food items such as cheese or meats.
Stretch film comes in different widths, lengths, gauges, hand grades, and machine grades. Enhanced versions of stretch film use higher alpha-olefins that make them more resistant to punctures and breakage. They also come in specialty variants such as colored stretch film, UV stretch wrap, and anti-static stretch film.
The size and type of stretch film packaging you select will depend directly on its intended application. There are four different classes of stretch film: Cast film, blown film, pre-stretch film, and high-performance film. All of these films are available in hand and machine grades.
Cast stretch wrap, is manufactured using a cast extrusion process. The Cast extrusion process is a continuous process by which a thermoplastic material is melted and extruded through a flat die onto a cooled roller which solidifies the film.
This process allows the Cast stretch film to have excellent clarity, require less force to stretch, increased tear resistance, unwind quietly from machines, and offer a superior cling.
Advantages of Cast Stretch Wrap:
Disadvantages of Cast Stretch Wrap:
Is manufactured using the blown extrusion process. This plastic melt is extruded through an annular slit die, usually vertically, to form a thin-walled tube. Then, air is introduced from an opening in the center of the die to blow up the film tube like a balloon. On top of the film tube, an air ring blows onto the film to cool it.
This process allows blown film to be more robust and more resilient than cast film. The higher mechanical properties of blown film typically allow a more significant load holding power, however, nano-technology blended cast films utilizing LLDPE, HDPE, and PP have recorded higher load holding force and containment force.
Advantages of Blown Stretch Wrap
Disadvantages of Blown Stretch Wrap
It is made as a co-extruded Blown Film, where It is stretched close to its ultimate break point prior to being wound onto rolls for its final use. What this means is that the film does not require as much stretching energy as a standard stretch film to achieve the same wrapping force. It also has excellent puncture resistance and is easier to apply than conventional blown and cast Films.
The resulting rolls are generally light and easy to handle, reducing operator fatigue. Since there’s very little torque involved, users also benefit by being able to use a walk-forward wrapping technique, which can help prevent slip and fall incidents.
Advantages of Pre-stretch film
Due to rising petroleum costs, stretch film manufacturers have made stronger, thinner stretch wrap. This thinner stretch film uses less petroleum resin during manufacturing, therefore costs less. These films are commonly referred to as “equivalent stretch film” because they will be made as a 63 gauge or less, but perform like a cast or blown 80 gauge, for example.
Performance stretch film uses a multi-layered technology to increase the strength of the film. The performance stretch film is a multi-layered stretch film that provides more stretch than traditional machine stretch film. It offers a high amount of cling and downsizing opportunity.
Advantages of Performance Stretch Wrap
Disadvantages of Performance Stretch Wrap
PVC is one of the most common plastics produced in the world. It was previously the most used shrink film until the introduction of other shrink films. Common PVC shrink wrap uses are CD and DVD packaging, software, and other non-edible items.
Advantages of PVC Shrink Film
Disadvantages of PVC Shrink Film
Polyolefin materials are available with different characteristics, including cross-linked wrap that provides high-tensile strength and great clarity. POF shrink wrap has taken the place of PVC shrink wrap in many applications.
Polyethylene is a single monomer wrap that is formed with the addition of ethylene during polymerization. PE shrink wrap is a heavy duty shrink film that is commonly used for larger commercial items.
Whether you are looking for stretch film or shrink film, Korpack is ready to help you choose the product that is best suited for your operations. If you want to know how we can help with your packaging needs, contact us today.
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