Stretch wrap

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Stretch wrap or stretch film is a very elastic plastic film that wraps around an item. Elastic restoration keeps goods tightly bound. Instead, the shrink wrap is loosely applied around the item and shrinks tightly with heat.

This is often used to unify the pallet load but can also be used to bundle smaller items. The stretch film types include bundling stretch film, hand stretch film, stretch core stretch film, film stretching machine and static dissipative film.

Video Stretch wrap

Materials

The most common stretch wrapping materials are linear low-density polyethylene or LLDPE, produced by ethylene copolymers with alpha-olefins, most commonly being butene, hexene and octene. Higher use of alpha-olefins (hexene or octene) provides enhanced stretch film characteristics, particularly in terms of resting on break and puncture resistance. Other types of polyethylene and PVC can also be used. Many films have about 500% stretch at rest but only stretches about 100 - 300% in use. Once stretched, elastic recovery is used to keep the load tight.

There are two methods of producing stretch wrapping. 1) Blown: the resin is melted and extruded through an annular die, cooled with air. This is a slower process but provides higher quality in all areas listed below. The cost of production is also higher because of the quantity that can be produced per hour. 2) Cast: the film is extruded through the die slot, then through the cooling roller. This makes the cooling process fast. The quality is not as good as blown but more can be produced within an hour at a lower cost.

Other properties such as break strength, cling, clarity, tear resistance, static discharge, etc. are also important.

Maps Stretch wrap

Function

In pallet unitization, stretch wrapping can have several functions:

• increase the stability of the product or package, form a unit of charge
• more efficient unit load handling
• some level of dust and moisture protection
• some levels of tamper resilience and resistance to theft packets
• some level of sun protection (UV stretch wraps)
• extend the shelf life of certain foods

Making sure the box stays on the palette and properly aligned is an important consideration in warehouse distribution, especially as demand for increased throughput continues to increase.

src: images.homedepot-static.com

Apps

Categories and subcategories of stretch wrapping:

Manual (or Hands ) Packaging:

• Additional core: The core extension of the film serves as a handle for wrapping; This type of wrapper offers little stretching and is hard on the hand.
• Mechanical brakes: Simple structures supporting film rolls and mechanical brake systems provide resilience creating a film's expanse.
• Pile wrapping: Similar to mechanical brake systems, but rolls and brakes are at the end of a long pole, creating an ergonomic design that eliminates the need to bend to wrap the underside of the load and strain to reach the top of the load. Used for space missions as well.

Semi-Automatic wrapping:

• Turntable wrap: The wrapped load is placed on a rotary table that rotates the load relative to the roll of film, which is placed on a carriage that can move up and down a "ship mast". Stretching is achieved by turning the load at a faster rate than the film is fed.
• orbital wrapping: This film is placed in the carriage on the vertical ring, the load is fed horizontally through the rotating ring, applying the film to the load. The variation of the orbital stretch wrap is the horizontal ring system, in which the load remains stationary while the horizontal ring is rotated around the load and moves up and down vertically relative to the load, similar to the wrap-arm stretch wrap.
• Swivel arm wrap: In this system, the load remains stationary while the rotating arm rotates the load. This system is used for light loads or for speeds that would otherwise cause the load to collapse due to the high rotation speed.

Automatic wrapping:

Automatic wrapping is generally a semi-automatic system variant. Automatic wrappers include a conveyor system for automatically loading wrap machines and automated systems for applying, sealing, and cropping films.

• Turntable wrap: The wrapped load is placed on a rotary table that rotates the load relative to the roll of film, which is placed on a carriage that can move up and down a "ship mast". Stretching is achieved by turning the load at a faster rate than the film is fed.
• Swivel arm wrap: In this system, the load remains stationary while the rotating arm rotates the load. This system is used for light loads or for speeds that would otherwise cause the load to collapse due to the high rotation speed.
• Rotary ring wrapping: The film is placed in the carriage on the horizontal ring where the load remains static while the horizontal ring rotates around the load and moves up and down vertically relative to the load, similar to the swivel stretch wrapper. Rotary ring technology is a more balanced system with less wear and tear than any other available packaging technology. The packaging is capable of reaching the highest production capacity (up to 160 pallets/hour).

src: www.interplas.com

See also

• Packaging and labeling
• Palletizer
• Plastic recycling
• Plastic wrap
• Sheet Slip
• Semiembossed film

src: www.airofilm.com

References

src: www.interplas.com

Further reading

• ASTM International D4649 Guide to Selection and Use of Stretch Wrap Movies
• Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & amp; Children, 2009, ISBN 978-0-470-08704-6

Source of the article : Wikipedia