Stretch film 101
Stretch film often is confused with heat shrink wrap. Though often confused, there is a big difference between the two. Below is a quick definition of stretch wrap.
Stretch Wrap- A highly stretchable plastic film commonly made from Linear low-density polyethylene that is wrapped around items. The elastic recovery keeps the items tightly bound.
Stretch film is commonly used to wrap products on pallets and secure them to each other and the pallet. This often helps to reduce products loss, discounrage load tampering, and reduce worker injury. There are a variety of widths, thicknesses, and types of stretch film. Below is a breakdown of the two most commonly used extrusion processes of stretch film.
Cast Stretch Wrap- Also called 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 chill roll, where it is quenched and re-solidified. 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. There are both machine grade and hand grade cast stretch film avilable.
Advantages of Cast Stretch Film- Generally less expensive than blown stretch film, due to reduced manufacturing costs. Increased clarity allows users to see wrapped products. Cast stretch wrap unwinds quietly compared to blown stretch wrap. Cast stretch film offers two sided cling that allows the wrap to stay securely wrapped.
Disadvantages of Cast Stretch Film- Does not offer the load/holding power blown stretch film offers. Cast stretch film has less memory and tear resistance than blown stretch film.
Blown Stretch Wrap- Also referred to as blown 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. Air is introduced via a hole in the center of the die to blow up the tube like a balloon. On top of the tube an air ring blows onto the film to cool it. This process allows blown film to be tougher and more resilient than cast film. The higher mechanical properties of blown film typically allow a greater load holding power.
Advantages of Blown Stretch Wrap- Offers higher load and stretch capacity. Blown stretch film is a higher quality of film. Blown stretch film has a higher degree of memory once stretched allowing loads to stay better secured. A higher tear resistance is an advantage when securing loads with sharp edges.
Disadvantages of Blown Stretch Wrap- Higher cost due to manufacturing process. Blown stretch wrap has poor clarity due to crystallization in the manufacturing process. Blown film is also noisy when unwound from rolls.
Frequently Ask Stretch Film Questions
When do I use Stretch Film?
Usually stretch film is used to hold boxes and products together on a pallet for transportation. It can also be used to hold other object together and protect objects during transportation and storage. Stretch film can come in a variety of specialty films. Some examples are: UV stretch film, vented pallet wrap, anti-static stretch film, colored stretch film, etc.
How do I know what size of film to use? Different sized thicknesses and widths of film are needed for different applications. Use the chart below to find which thickness and width would be ideal for your application.
What is equivalent stretch film?
Due to rising petroleum costs stretch film manufacturers have been persuaded to make stronger thinner stretch wrap. This thinner stretch film uses less petroleum resin during manufacturing, therefore costs less. The equivalent stretch film uses a multi-layered technology to increase the strength of the film. Different manufacturers have different names for their equivalent films. The two equivalent hand stretch films we offer are Hybrid stretch film and Micron stretch film. We also offer our Performance line of machine stretch film that is thinner stronger and offers users the ability to save on costs.
Hybrid stretch film is a thinner stretch film with a super strong resin formula. It is the thinnest strongest film we offer, but is not recommended for loads over 1800 lbs. Because the film is thin, it does not have the same amount of tear resistance as a thicker film.
Micron stretch film is a film in-between the "true gauged" stretch film and the Hybrid stretch film. It is a multi layered film that offers great cling, stretch, and tear resistance. It offers users the ability to reduce costs while staying confident about load security.
Performance machine stretch film is our answer to rising machine stretch film costs. The performance stretch film is a multi-layered machine stretch film that provides more stretch than traditional machine stretch film. It offers a high amount of cling and down sizing opportunity.
Are there any advantages to using opaque stretch film?
Opaque stretch film offers a variety of advantages over clear stretch film. A few advantages include:
1. Detours pilferage through valuable shipments by concealing products.
2. Helps to protect products from UV Rays.
3. Prevents damage caused by rain, dew, and dust.
4. Outlasts regular clear stretch film during extended outdoor storage.
5. Great for color coding products.
Do I need UV stretch Film?
UV protection can help extend the life of the stretch film when stored in the sun. The use of an opaque UV stretch wrap can increase the storage life of the film and the product when stored outside. Anyone should consider UV stretch for any shipments stored outside longer than 60 days.