FAQs On Stretch Films
What is Banding?
Banding is when the film is narrowed to a smaller width to retain heavy or awkward loads. This also ensures that heavy or awkward loads are firmly attached to the pallet. IBIS Packaging can provide pallet wrappers with automatic banders or manual banders
What is Blown Film?
Blown stretch film is produced by an extrusion process that blows a large elongated bubble of 3 or 4 meters vertically into the air. This orientates the film molecules in a crisscross arrangement. Stretch film extruded by the blown method typically produces greater puncture resistance but less aesthetic values in comparison to cast films which give a much higher yield, resulting in a lower wrapping cost.
Product example: blown hand stretch film
See also: stretch film standard specifications and stretch film calculator
What are Bottom Wraps?
The rotations a stretch wrap machine makes when applying stretch film to the lower portion of a unitized load. Bottom wraps of more than one rotation augment pallet stability.
See also: packaging equipment distributor
What is Cast Film?
Cast stretch film, extruded by the cast method, is produced on a flat wide extruder with a large chrome chill roller that cools the film down quickly. This gives cast film higher transparency and produces a film with molecules frozen in the machine direction. This typically produces a stretch film with greater tear resistance, greater aesthetic values and is quieter to unwind in comparison to blown stretch films.
Product examples: machine cast stretch film, hand-cast stretch films
See also: stretch film types
What is Cling Effect?
The cling effect in industrial stretch film ensures the film sticks to itself but not to the product being wrapped. Films will be designed with a single-sided cling or a two-sided cling. The cling effect on stretch film is produced on a molecular scale working a bit like Velcro. Some blown films put a PIB additive in which makes them sticky. The PIB transfers to the rubber rollers on industrial pallet wrappers and this stretch film should be avoided. Its main use is in agriculture.
See also: stretch film types
What are the Testing Methods for Film?
Dart drop: A technique used to measure the impact strength or sturdiness of a film; this is ascertained by dropping a crescent-shaped weight (aka dart) onto a film.
Elastic Recovery: The stretch film is stretched, strained and/or deformed, its ability to recover and return to its original form indicates its elastic recovery capacity.
Elmendorf Tear: A testing method for measuring a materials ability to resist tearing forces. This method initiates a tear in a sample material, then measure the amount of force needed to tear the sample apart. Test result value is referred to as the tear value.
What is an Extruder?
A piece of equipment that uses mechanical and thermal actions to change solid polymer granules into a molten polymer liquid which is forced out onto a chill roller or blown up into a vertical bubble. The polymer is then cooled and stretched producing a polythene stretch film
What is Film Force?
As the film is applied the rate of tension in the film is called the film force or film tension. This can also be called a secondary stretch. Elongating stretch film invokes the film memory. The stretch film molecules want to return to its original position. This elastic band effect is what is required to make sure you have good load integrity.
What is Film Tail?
The film tail refers to the start and end pieces of stretch film that are initially applied and then later cut off from a pallet in the stretch wrapping process.
What is Gauge?
An imperial measurement used to measure stretch film thickness or calliper. An example value would read as: 70 gauge, 80 gauge or 100 gauge.
Also note: Often used as a synonym for film thickness.
See also: stretch film conversion calculator
What is Stretch Gloss?
Stretch gloss refers to a surfaces shine or sparkle, in LDPE stretch films it refers to the amount of light that is reflected from the stretch films surface. High gloss attributes are typically found in cast stretch films.
Product example: machine cast stretch film and hand-cast stretch film
What is Hand Film?
Hand stretch film is used for manual stretch wrap packaging application. Designed for hand wrapping application, hand film rolls are lighter and smaller than machine film rolls to make application easier. Also known as hand wrap, hand stretch wrap and hand stretch film.
Product example: hand stretch film
What is Film Haze?
Refers to a lack of clarity and inability to see through a film, it is measured by the percentage of light not transmitted through a film sample. Characteristic is typical of blown stretch films.
Product examples: blown stretch film and hand-blown stretch film
What is Impact Strength?
The capability of a stretch film or other material to defy rapidly applied destructive forces.
What is LDPE Stretch Film?
Low-Density Polyethylene Stretch Film
Product examples: stretch films
See also encyclopedia definitions: low-density polyethene
What is LLDPE Stretch Film?
Linear Low-Density Polyethylene Stretch Film
Product examples: stretch films
See also encyclopedia definitions: linear low-density polyethene
What is Machine Direction?
Machine direction refers to the direction perpendicular to the film width. Acronym: MD. Machine Films is a stretch film designed for stretch film equipment.
Product examples: machine stretch films
What is Metallocene?
New polyethene resins developed using Metallocene change the polyethene chain structures resulting in a new breed of stretch films. Metallocene stretch films can achieve increased puncture resistance and clarity while blends offer balanced film properties and universal stretch percentage applications (ex: machine film, hand film).
Product examples: machine stretch films and hand stretch films
What are Microns in Film Width?
Microns is a metric measurement used for measuring film thickness. One micron is equal to one-millionth of a metre or a thousandth of a millimetre.
See also: microns to gauge conversion calculator or standard stretch film sizes, weights and gauges
What is Neckdown?
Neckdown is when a stretch film losses its dispensing roll width/breadth and narrows down while being stretched. Neckdown reduces coverage each wrap provides thereby making it likely that more wrap rotations and more film will be needed to wrap a load or pallet.
What is Overwrap and How Does it Happen?
Refers to the amount of stretch film applied over the top of the load. Overwrap provides a downward force on a pallet load and is often used to secure a pallet top sheet or corrugated top cap in place. Pallet Covers Poly film covers commonly used to protect pallets from dirt, dust and/or conceal pallet contents.
Product examples: palletising products, pallet covers and sheeting film
What is Poststretch?
Post stretching is stretching a film by using the load to pull the film out at the same time as it applies film. Although this allows for the benefit of film tension, the tension levels are inconsistent and as such can damage many load types. Attempts to attain higher tension stretch can be done but can increase the risk of damaging some load types and increase chances of stretch film breakage.
What is Film Pre-Stretching/Power Stretching?
Pre stretching is the process of stretching the film prior to application. The process can increase film strength, improve load integrity, reduce the amount of stretch wrap film needed and save on stretch film packaging costs. Optimal pre-stretch values can be attained with leading-edge and high-performance stretch wrap machines as well as stretched films for manual application operations.
Product examples: machine stretch films and hand stretch films
See also: stretch film types and buy, lease or rent stretch wrap machinery
What is Stretch Film Roping?
Bunching the stretch films full width to create a rope is known as roping. Stretch film roping is extremely strong and is often used to further secure a pallet to its load. Bunching stretch film is a feature function of many stretch wrap machines (ex: turntable stretch wrappers).
See also: buy, lease or rent stretch wrap machinery
What is Stretch Film Tear Resistance?
This refers to the resistance of the film to tear. The attribute is quantified by measuring the force needed to propagate an initiated tear. Tensile strength is a measurement of the maximum amount of force a material can withstand without breaking. The greater the tensile stretch measurement, the stronger the material.
See also encyclopedia definitions: tensile strength
What is Film Tension Stretch?
Tension stretch is a pulling force that stretches materials. For example: stretching a rubber band will make it longer, as it gets longer its tension increases. This is also referred to as post stretch.
See also: post stretch
What is Transverse Direction?
Refers to the direction across the stretch film web. Also referred to as TD.
What is Film Wide Web?
A speciality sized large film roll designed for equipment that wraps using larger widths.
Product example: wide web pallet wrap
What is Yield Strength?
Yield strength is the amount of stress a material can withstand without permanently having plastic deformation. Prior to reaching, a material will elastically deform but will return to original shape once the stress is removed.
See also encyclopedia definitions: yield strength
What is Zippering and When Does it Happen?
Refers to the lack of resistance of an initiated TD tear or cut. Once initiated, the tear will rapidly spread.