What is 80 Gauge Stretch Wrap?
What is 80 gauge stretch wrap? Everyone who is familiar with stretch wrap knows the term 80 gauge stretch wrap. Many people do not know what 80 gauge stretch wrap means though. This post is to detail exactly what 80 gauge stretch wrap is and to explore how other options can be advantageous to traditional 80 gauge stretch film.
Why Does It Matter?
If a location uses stretch wrap on a regular basis, knowing the type of film being used is important for several reasons. If a company is using a true 80 gauge stretch wrap and orders from another company that claims their film is an 80 gauge stretch wrap, products can be damaged in transportation from using an inferior film.
If companies believe they are using an 80 gauge stretch wrap, ordering a true 80 gauge stretch wrap would be over gauging and cost the company more money. It is also important to know the film being used to obtain accurate quotes.
80 Gauge Stretch Wrap
The term 80 gauge stretch wrap refers to the thickness of the wrap. A gauge is a form of measurement used to measure thin plastics. This is often confused, but not the same as a wire gauge for measuring how large wire is. To view a gauge conversion chart click on the link. For this post we have converted 80 gauge film thickness to other commonly used units of measurement for plastics.
80 Gauge = 20 Micron
80 Gauge = .80 Mil
80 Gauge = .0203 Millimeter
80 Gauge = .0008 Inch
The most common measurement used when referring to stretch wrap is gauge, micron, and occasionally mil. Micron is a very common form of measurement when referring to stretch wrap. An 20 micron stretch wrap is the same thickness as an 80 gauge stretch wrap. Just because two stretch films are the same thickness does not mean they are the same film quality. See below for common differences between 80 gauge stretch films.
Differences Between 80 Stretch Wrap
Two films that MIC out to the same thickness are not necessarily the same film quality. The standard for years was a true 80 gauge stretch wrap with up to a 200% stretch. That means when the film is applied properly it can be stretched up to 200% of its original length.
Even this standard can vary depending on the type of extrusion process. Stretch film manufacturers use two different kinds of extrusion processes, blown and cast. Each type of extrusion process produces different film characteristics. We will discuss in further detail below.
Features such as the overall stretchability of a stretch film can be adapted through the extruders resin mixture. Extruders often include additives to resin mixtures for a variety of reasons. One of the most common resin additives is UV inhibitors.
Over time extruders of stretch wrap adapted resin mixtures to accommodate changing trends. A key factor in the development of new resin mixtures was the increases in petroleum prices. Since stretch wrap is a petroleum based product, a resin mixture using less petroleum can save on film cost. Another factor in resin mixture changes is users not reaching the maximum stretch potential. With a 150% to 200% stretch, applying a hand stretch film requires strenuous pulling to apply the film. Below we are going to look at everything in further detail.
Blown vs. Cast 80 Gauge Stretch Film
As mentioned above, a standard 80 gauge stretch film can have varying characteristics depending on the manufacturing process. The most common film extrusion processes are cast extrusion and blown extrusion. Cast extrusion uses chilled rollers to cool film resin and blown extrusion uses air to cool film resin. For an indepth read about the two processes read our previous blog post titled Plastic Extrusion For Stretch Film.
Common differences found between 80 gauge cast stretch film and 80 gauge blown stretch film are:
80 Gauge Cast Stretch Film - Clearer, quieter unwind, less puncture resistance
80 Gauge Blown Stretch Film - Loud unwind, hazy, higher puncture resistance, higher cost
If someone is used to using a blown 80 gauge stretch wrap and tries a cast 80 gauge stretch wrap they will notice a substantial difference between the two films. This is one of several reasons 80 gauge stretch wrap film can vary.
Different Resin Mixtures
Because of the factors mentioned above, stretch film extruders have adapted resin mixtures. New resin mixtures enable film to be thinner and stiffer, yet offer the same load retention as true 80 gauge stretch wrap. Many stretch wrap extruders and distributors call these new resin mixtures 80 gauge stretch wrap when the film does not actually MIC out to 80 gauge or 20 micron. The film has a load retention equivalent to 80 gauge, but it is not the same thickness.
There are only a couple ways to determine if a stretch film is a true 80 gauge stretch wrap. The best way to determine film thickness is the use of a micrometer. A micrometer is a measuring tool used to measure the thickness of objects. Another option for determining the thickness of stretch wrap is a film thickness equation.
If you know the weight of an unused roll of stretch wrap you can determine the thickness of the stretch wrap roll. Use the formula below to determine the thickness of stretch wrap.
Roll Weight ÷ Roll Width ÷ Roll Length ÷ 12 x 30,000 = Film Thickness
Example for an 18"x1500' stretch wrap roll weight 8.64 lbs
8.64 ÷ 18 ÷ 1500 ÷ 12 x 30,000 = .80 or 80 gauge
It is not necessarily a bad thing if the film being used is not a true 80 gauge stretch wrap. Equivalent stretch wrap is designed to save companies money by using less petroleum and increase efficiency. If you have any questions about the stretch wrap you are currently using or other possible options, feel free to call us at 1-800-441-5090.