Stretch Wrap 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 (LLDPE) 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, discourage load tampering, and reduce worker injury. Read: What is stretch film used for. 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 available.
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.
Read our blog post about the stretch film extrusion process.
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.
|Thickness Width>||2"-5" Banding||12"-20" Hand Grade||20" Machine Grade|
|60 Gauge||Ideal for lighter smaller objects, small boxes, and banding light items together. Many moving companies use light gauge banding stretch film in place of tape.||Ideal for loads up to approx. 1300 lbs. 12", 15", and 18" widths are ideal for shorter loads or loads where bottom and top only need to be wrapped.||Same strength as 12”-20” hand Stretch wrap. Machines promote more efficient wrapping and reduce waste.|
|70 Gauge||Same uses as the 60 gauge, but enables slightly stronger holding strength.||Ideal for loads up to approx. 1600 lbs.12", 15", and 18" widths are ideal for shorter loads or loads where bottom and top only need to be wrapped.||Same strength as 12”-20” hand Stretch wrap. Machines promote more efficient wrapping and reduce waste.|
|80 Gauge||The most common gauge in all stretch wrap. Known to be very versatile and handle a variety of applications||Ideal for loads up to approx. 2200 lbs. 80 gauge is the most common stretch film thickness and ideal for a variety of applications||Same strength as 12”-20” hand Stretch wrap. Machines promote more efficient wrapping and reduce waste.|
|90 Gauge||Uses are comparable to 80 gauge stretch film, but has increased strength.||Ideal for loads up to approx. 2400 lbs. 90 gauge is a starting thickness for heavier film. The 18" and 20" 90 gauge and above is ideal for taller or heavier loads.|
|100 Gauge||Commonly used for heavier boxes and products to bundle together. Medium heavy boxes and medium heavy items such as light lumber are ideal.||Ideal for loads up to approx 2800 lbs. The 18" and 20" 100 gauge and above is ideal for taller or heavier loads.|
|115 Gauge||Used for smaller heavy objects, commonly used for banding lumber together.||Ideal for loads up to approx. 3000 lbs. The 18" and 20" 115 gauge and above is ideal for taller or heavier loads|
|150 Gauge||Greater strength and puncture resistance, great for regular and irregular shaped boxes. Ideal for securing heavier loads..||Ideal for loads up to approx 3500 lbs. The 18" and 20" 90 gauge and above is ideal for taller or heavier loads|
Suggested stretch film load limits are only to give a general idea of load capacity. They should not be construed as specification limits. Click here to view our gauge conversion chart. For technical stretch wrap data click here.
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. Both hybrid and micron stretch film are considered an eco friendly option for reducing film waste.
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.
Is shrink wrap and stretch film recyclable?
Both shrink wrap/film and stretch film/wrap are recyclable. Check with your local recycling center and be sure they accept soft plastics.
Do I need a special stretch wrap machine?
Stretch wrap machines are recommended for any business wrapping more than 15 loads per day. Stretch wrap machines help to reduce waste, increase efficiency, and promote a more secure and consistent load.
There are a variety of manual stretch film dispensers and products for businesses that stretch wrap less than 15 loads per day. Extended core stretch film is ready and easy to use out of the box. It is great for businesses that need stretch film, but do not ship many loads. Two-handed manual stretch film dispensers are recommended because of ease of use, a built-in braking system, and the ability to tightly secure loads.
How do I stretch wrap a pallet?
Extract approximately a yard of plastic off the stretch film roll, squeeze 8 to 10 inches of the end together to form a rope shape. Thread the rope part through one corner of the pallet. A knot is not necessary. Begin wrapping around the base of the pallet. Wrap the base of the pallet at least five times while keeping the film tight as pulled off the roll. Slowly work your way up the box, focusing on keeping the wrap tight. The goal is to have all of the products stay together as one. Once at the top of the pallet, push the top boxes to see if they move or if they are one with the bottom boxes. If they move, wrap your way back down to the bottom of the pallet.
Common Stretch Film Terms
Blown Stretch Film- A stretch film derived from the blown extrusion process that has a greater puncture resistance. Click on the stretch film info page to view detailed information about blown stretch film.
Bottom Wraps- The wraps a stretch wrap machine uses to apply film to the bottom section of the load. Forming a strong bottom wrap will help to ensure load stability.
Cast Stretch Film- A stretch film derived from the cast extrusion process. Less manufacturing costs allow cast stretch film to be the more widely used stretch film. Visit the stretch film info page to view detailed info about cast stretch film.
Cling- Allows the film to stick to itself and not the product. Some films have one sided cling and others have two sided cling.
Co-extrusion- Extruding two or more materials through a single die to enable the two materials to merge together.
Dart Drop- A commonly used test to measure puncture strength of a stretch film. It is conducted by dropping a semi-circular shaped object onto the film.
Elastic Recovery-The ability of a stretch film to recover to its original shape after being stretched.
Elmendorf Tear- Another common test used for stretch film and other products to measure tear resistance.
Extruder- Equipment used to change solid polymers into molten polymers.
Film Feed- In a stretch wrap machine, it is the speed at which stretch film is supplied to the load.
Film Force- Refers to the amount of tension applied to the film as the film is applied to the load.
Film Memory- The ability of the film to return to its pre-stretched form. This enables the film to maintain a tight load during transportation.
Film Tail- The start and end pieces of stretch film applied to the load. Generally these pieces are cut off later
Gauge- A measurement used to measure film thickness or caliper. One gauge is equal to .254 microns. Microns are another common form of film measurement.
Gloss- The amount of light reflected from a film’s surface. Cast stretch films tend to have a higher gloss than blown stretch films.
Haze- Refers to lack of clarity in a film. Blown stretch films commonly have more haze than cast stretch films due to crystallization during the manufacturing process.
LLDPE Stretch Film- Linear Low Density Polyethylene stretch film. A plastic that is preferred in a variety of film due to its toughness, stretchability, and relative transparency.
Metallocene- A compound used to make a new form of stretch film. Metallocene stretch films offer increased puncture resistance and many other useful benefits.
Microns- A unit of measurement commonly used to measure the thickness of a film. A micron is equal to one millionth of a meter. One gauge is equal to .254 microns.
Over wrap- The amount of stretch film applied over the top of the load. It is used to provide a downward force on the load.
Pallet Covers- A poly film cover used to protect pallets from dust, UV rays, and conceal the load. Feel free to check out the various pallet covers we offer.
Post-stretch- Stretching a film when wrapping the load to achieve tighter tension on the load
Pre-stretch- Stretching the film before applied to loads. Pre-stretch films can result in improved load integrity and lower packaging costs.
Roping- Bunching the stretch film into a rope shape. Roping used to start many loads and offers an increased strength for additionally securing a load.
Tackifiers- Additives used in the manufacturing process to add cling to the film.
Tear Resistance- Refers to the resistance of the film to tearing forces.
Tension Stretch- A pulling force that stretches the materials
Wide Web Stretch Film- A large sized film used for larger equipment. Generally it refers to machine stretch film wider than 30 inches
Yield Strength- The amount of stretch a film can have without permanently deforming.
Stretch Wrap Equipment
Choosing the right stretch wrap machine should be a careful consideration for any business. There are several factors to consider when making your choice. Below are a few questions to consider.
1. How many loads are you currently wrapping and how many loads do you foresee wrapping? This will help to give you a good idea of what equipment to invest in.
2. What types of loads will you wrap? Will the loads all be boxes, irregular shapes, fragile, etc. Are the loads heavy, light, stable, unstable, etc. Different machines are used for different applications
3. How much do you want to spend? Machines can vary dramatically in costs depending on the features and output capacity require
Types of Stretch Wrap Machines
Turntable Stretch Wrap Machine- One of themost common forms of stretch wrap machines. Depending on which type chosen, they can meet the needs for the majority of applications. There are a large variety of turntable machines to choose from. Semi-automatic machines are good for less than 30 loads and hour. Semi-automatics are designed for use with a forklift or a pallet jack. The fully automatic machines are used in conjunction with conveyor belts and are used for high capacity output.
Straddle Stretch Wrap Machine- Features a rotating arm to move around the load. These machines are commonly used for light, fragile, unstable, and loads to heavy for turntable machines.
Horizontal Stretch Wrap Machine- These machines use a rotating film carriage that moves around a load as it passes through a horizontal ring. Horizontal machines are typically used for fully automatic operations.
Stretch Machine Terms
Brake Roller- A mechanism on a stretch wrap machine that slows the rate in which film is fed to the load and increases tension between the load and film.
Dancer Bar- A roller found on stretch wrap machines that measures film feed. It will adjust the film feed on corners to allow a continuous tension.
Film Feed- The speed in which the film is applied to the load.
Film Force- The tension of a film put on the load, usually measured in pounds.
Film Force Release- A machine feature that releases tension when unwanted.
Load Diagonal- The measurement diagonally across opposite corners of the load. These measurements are required to determine machine size.
Pre-stretching- Stretching the film before applying it to the load.
Simple Automatic- A type of stretch wrapping machine that allows a forklift operator to not leave the forklift to initiate wrapping.
Wrap Parameters- Adjustable load retention settings. Allowing user to adjust a variety of wrapping settings.
Benefits of Stretch Film
Stretch film is one of the most popular methods of pallet wrapping. It is cost effective, it offers a superior protection, and is adaptable to fit many load applications
Stretch Wrap Protection- Stretch wrap offers a secure option for wrapping loads. The option of UV stretch films can help protect products from the sun. Stretch films can also help protect products from dust, debris, and moisture.
Cost Effective- Stretch wrap is less expensive than strapping and other types of pallet wrapping. Equipment is often cheaper to acquire than other methods as well. Mechanical stretch wrap equipment typically requires less energy to operate than other alternatives.
Recyclable- Stretch film is recyclable.
Adaptable- There is a wide variety of stretch films available for different applications. Stretch wrap can be applied to flat surfaces as well as pointed surfaces.
Stretch Film Videos