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Stretch Films are elastic films that are frequently made from linear low density polyethylene, also referred to as LLDPE films. This LLDPE film is produced when ethylene and alpha-olefins undergone process called copolymerization. Some common alpha-olefins are octene, butene, and hexene – the higher use of these increase the elasticity features of the stretch film.
With its puncture resistant quality, high tearing capacity, and tensile strength, the LLDPE films are then used for packaging goods to preserve integrity and prevents damages that is brought about by transportation and distribution. Noting that LLDPE films are flexible enough to be stretched out up to 500%, although it is known that stretch wrapping equipment available in the market only does until 300% of the elongation. As the film elongates, it increases its tensile strength making pre-stretch films more durable than that of the standard version.
The manufacturing of stretch films comes in two kinds, either produced from blown or cast processes.
Blown Stretch Film is the procedure in which resin is placed in an extruder, heated for melting, and blown vertically into a bubble. It is then cooled down by surrounding air and rolled on a paper core then after. As for Cast Stretch Film, this includes a course in which resin is still heated with an extruder, but it is next cooled down by chilled rolls that solidifies the film and made into rolls.
|
|
Blown Stretch Film |
Cast Stretch Film |
|
Finish/Clarity |
Foggy and dull |
Glossy and clear |
|
Noise |
Loud when being unwound |
Quieter when being unwound |
|
Tensile Strength |
High puncture resistance |
Standard puncture resistance |
|
Load Retention |
Will not stretch after application and has great hold of palletized goods giving reliable stability |
Will stretch even application is done, thus, giving a less stable finish |
|
Film Memory |
Can return to original condition even after being stretched |
Has lower capability to return to its initial form |
|
Cling |
1 Side This makes film stick to the palletized goods without sticking with other pallets |
2 Sides This makes film stick to both the palletized goods and other pallets in transit |
|
Film Coverage |
Stretches better and uses less film for same amount of pallets |
Not much stretch than blown film |
Hand wrapping method is usually being applied by industries with lower volume production needs. Palletized goods are manually being wrapped, hence, the film roll is way lighter and shorter than that of the stretch films used in machines. Then a hand dispenser aids this type of operation when it comes to the releasing of film on roll, user is the one who stretch the film to their full potential making it quite expensive and inconsistent. Although trained operators have the ability to wrap palletized goods, specially irregularly shaped ones or unstable stacks and it is better manually done than machine operated.
These types of pallet wrapping machines are typically used for medium volume production needs to high volume. Industries that wraps 100 pallets or more a day is suggested to invest in a semi-automated machine for efficiency compared to hand wrapping method. Equipment are traditionally made with a turntable for palletized goods to move in circles for film wrapping and some may also have a rotary arm with an eliminated table for ergonomic resolve. Either way, this semi-automatic equipment performs a programmed pattern in which it wraps the load.
Industries of high volume pallet wrapping application requirements are recommended to invest in fully automated machines. Businesses with this type of wrapper comes from the large sectors since the cost of investment is high compared to manual and semi-automatic method. The whole process of packaging using stretch wrap is initially programmed and is integrated in a line of machines that the goods needed processing on – keeping in mind that the pallet wrapper equipment is the last course the goods will go through.
Looking for the best film for you depends on a couple of factors. From your machine to the products needed to be stretched wrapped.
Questions needed to be weighed are:
1. Is manual hand wrapping used?
2. If not, what is the machine being used? What type?
3. What are the materials/products being wrapped?
4. How much load does your warehouse process in a day? Or, how many completed pallets are your desired output?
5. Where does the palletized goods go for distribution?
6. How many variations of load is being wrapped in your warehouse?
For more needed support in finding the best wrapper and film, do not hesitate to contact us at support@sal-tech.com. We’re glad to be of assistance.