Stretch Film Glossary of Terms

By |2018-01-25T08:46:01+00:00January 25th, 2018|Packaging Strategy, Packaging Supplies|0 Comments

In the industrial markets, stretch film is one of the most commonly used products you find. 

It is commonly made from a product called linear low-density polyethylene (LLDPE) and used in bundling applications.  Stretch film, also sometimes referred to as pallet wrap, or stretch wrap, has a stretchable characteristic allowing it to be used to wrap pallet loads, bundle small products, and/or simple unitization.

Its film memory and puncture resistance keep the product safe throughout transit.  The type of stretch wrap you use for your application may vary based on the product, weight, and size.  You can find this packaging film as small bundling films, hand stretch film, and machine stretch films.

To that end, here are some common stretch film terms that you should be familiar with.

Stretch Film Terms

Asymmetrical Load: An unevenly aligned pallet load. Asymmetrical loads are more prone to toppling than symmetrical pallet loads.

Adhesive: A substance, such as glue, used to laminate two structures together.

Banding/Bundling: When several items are secured together with plastic stretch wrap.

Base Lock: The thick layer of film produced by holding a hand wrapper at approximately a 45-degree angle to the floor, helping to lock the boxes to the pallet, preventing the load from shifting.

Blown Film: Film manufactured using the blown film extrusion process.  Typical characteristics include: poor optics, hazy, dull, excellent puncture resistance, very noisy unwind and high force on load.

Bottom Wraps:  The wraps a stretch wrap machine uses to apply the film to the bottom section of the load. Forming a strong bottom wrap will help to ensure load stability.

Cast Film: Film manufactured using the cast extrusion process. Typical characteristics of cast stretch films include excellent optics, clear, glossy, superior tear resistance, quiet unwind, consistent cling and consistent film thickness.

Cling: The feature of a stretch film which makes it stick to itself and not the product.

Coefficient of Friction (C.O.F.):  The amount of slip shown when one surface is dragged against an adjacent surface.

Co-extrusion:  Extruding two or more materials through a single die to enable the two materials to merge together.

Converting:  The process of converting sheets or rolls of a product such as paper, film, or foil to a finished product.

Core: Tube on which product is wound.  Cores are commonly made of paper or plastic.

Cross Top Wrapping:  A technique to wrap a load across the top.   Cross Top Wrapping helps to keep the load together as it settles during shipment.

Dart Drop:  A test used to measure the puncture strength of a stretch film.  Conducted by dropping a semi-circular shaped object onto the film.

Die: A device used in extrusion processes to shape the extrudate.

Elastic Recovery: The ability of stretch film to return to its original form after it is stretched.  This characteristic is what keeps the stretch film tightly formed to the load, thus helping it to stay intact during shipment.

Elmendorf Tear: A test used for measuring tear resistance.

Elongation:  The linear stretch of material during tensile loading.

EVA (Ethylene Vinyl Acetate):  A copolymer that, when added to stretch wrap, increases its strength.

Extruder:  A machine that makes the stretch film by turning solid polymers into molten polymers.

Feed:   When using a stretch wrap machine, film feed 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.

Stretch Film Memory: The ability of stretch film to recover and form fit a load after being stretched.

Film Tail:  The start and end pieces of stretch film applied to the load. Generally, these pieces are cut off later.

Flange:  The extended lip of the handbrake that keeps the operator’s hand from sliding down and rubbing against the roll.

Gauge: The thickness or caliper. One gauge is equal to .254 microns

Gauge Band:  Thickness irregularity in films.

Gloss: The amount of light reflected from a film’s surface. Cast stretch films tend to have a higher gloss than blown stretch films.

Hand Stretch Film:  Stretch film designed for manual use.

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 preferred in a variety of film due to its toughness, stretchability, and relative transparency.

Machine Stretch Film:  Stretch films (cast machine stretch film, blown machine film, and converted films) designed for application with a stretch wrap machine.  Some of the advantages include faster and more efficient packaging, reduced packaging material costs, safer application, more secure loads and more.

Metallocene- A compound used for increased puncture resistance and many other useful benefits in stretch film.

Microns- A unit of measurement commonly used to measure the thickness of a film. A micron equals to one-millionth of a meter. One gauge is equal to .254 microns.

MSDS Sheet- Stands for Material Safety Data Sheet. A detailed list of information about a specific product and potential safety hazards the product may have.

Laundry Wraps:  All-purpose PVC films used in commercial laundries.

LDPE or PE (Low-Density Polyethylene):  A resin base for making the stretch film.

Master Roll:  A finished roll that comes off the press

Maximum Stretch:  The ability of the film to stretch to its limit without tearing.

Neck Down:  The narrowing tendency of the stretch film when being stretched or pulled.

Overwrap- The amount of stretch film applied over the top of the load.  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.

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.  Used to start many loads and offers an increased strength for additionally securing a load.

Symmetrical Load- An evenly aligned pallet load with flush sides.

PVC (Poly Vinyl Chloride): In film form, this film is used as a meat or produce wrap as stretch film, and a high clarity shrink wrap for retail packaging.

Slip: Term used to describe the amount of COF (coefficient of friction) on the surface of a substrate such as paper, film, or foil.

Slitting: Cutting a large master roll into small rolls used.

Tacifier:  A general term used to refer to cling additives in stretch film.

Tear Resistance- Refers to the resistance of the film to tearing forces.

Tear Strength:  A measure of how likely a material will continue to tear once started.

Tensile Strength: The greatest longitudinal stress that stretch film can take before it tears.

Tolerance: Allowable deviation from a nominal or specified dimension.

Top Sheeting:  A protective covering put on the top of a load to protect the top from dust, dirt, and other objects that might damage the load.

Unitization:  Wrapping techniques that protect a pallet load from top to bottom, making all packages in the load one single unit.

UOM: Unit of measure.

UVI Stretch Film –  Film with Ultra-violet inhibiting additives that protect the film from breaking down when stored outdoors.

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 gets without interfering with the performance of other properties like tear and puncture resistance.

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As you can see from the glossary list above, stretch film can be widely variable in scope and product use. But have no fear, at Axis Packaging we have the knowledgable staff to point you in the right direction.

Do you have more questions?  We can help.  Contact us now at 1-877-410-5564 or email us at info@axispack.com.

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