When was pallet wrap invented?

There are many different plastics in use today, and the polymer used in shrink wrap is one of the most popular. It's easy to understand why shrink-wrapping is so commonplace these days. After all, it keeps products stacked together, foods fresher for more extended periods, and reduces transportation and storage loss. If you've ever been curious and wondered, "When was shrink wrap invented?" it all started in 1933 when an employee at Dow Chemical in Midland, Michigan, was asked to develop a new product from two existing ones - hydrocarbon and chlorine.

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In the Beginning…

Ralph Wiley, a 1930s Dow Chemical employee, is credited with creating polyvinylidene chloride (PVDC) while working with two byproducts of a manufacturing dry-cleaning agent known as perchloroethylene. At first, called his invention eonite because it reminded him of an indestructible agent he read about in the Little Orphan Annie series. He discovered that the molecules in his invention would bind tightly and therefore weren't penetrable by water or oxygen molecules. In addition to helping with the war effort, this invention also led to the creation of Saran Wrap in the 1950s, although today's Saran Wrap is made differently.

While PVDC was an accidental discovery, it instantly became desirable as a food wrap, mainly because it could hold in odors, cling to itself, and survive in the microwave. But perhaps the main advantage of this discovery was that it led to the development of shrink wrap. Even though shrink wrap has some environmentalists concerned, its use doesn't seem like it will be diminishing anytime soon. To learn how we got from PVDC to shrink wrap, let's look at the process.

First of all, knowing that plastic and heat have a close relationship helps you understand how shrink wrap got started. When plastic is exposed to high temperatures, the molecules get configured into a new shape. This results in a tighter and firmer plastic than it was in the beginning. The plastic even reshapes itself around an item because it creates a close fit.

Raychem and Its Contribution to Shrink Wrap

In 1957, Raychem was founded and specialized in creating a type of heat-shrink tubing used for electrical wiring. A kind of radiation treatment was applied to the plastic to do this. The tubing used a little heat so that handmade wiring work was a little more secure, and it also prevented the wires from being exposed. Simply put, the small amount of heat they used meant it was easier to repair wires because the changes were kept in place because of the heat. Paul Cook, was the inventor of this process at Raychem.

Now let's back up a few years. In the late 1930s/early 1940s, companies such as Butterball used a process called cry-o-vac to vacuum-seal chickens and turkeys inside of bags. They wrapped a plastic film around the entire bird and it was dipped in a hot water bath for the packaging to shrink and conform to the bird. Afterward, the bird was frozen and put through several heat and cooling cycles. This, in turn, firmed up the packaging and allowed the birds to be preserved longer.

In 1946, Cryovac, Inc. was formed, and it became the leading company to offer this technique to poultry manufacturers. The method is essentially a precursor to the shrink-wrap process.

This heating-chilling process for plastic was a super-advanced innovation, but companies still wanted to improve upon it. When Bill Baird at Cryovac and Paul Cook, the inventor of heat shrink, met, they compared notes and worked to improve the process. This was when they decided that if you applied the concepts that involved irradiated polyethylene to turkey bags, the process came much closer to what we call shrink wrap today. Nevertheless, the freeze-heat-chill technique needed some improvements, which eventually resolved themselves and became what we now call the shrink-wrapping process.

The Biggest Advantages of the Shrink-Wrapping Process

If you're not convinced that shrink-wrapping is a widespread technique, consider what we use it for today:

● In the packaging of perishable foods: Shrink-wrapping can be used to preserve raw meat, fruits and vegetables, and so much more. The process may have started with whole turkeys, but it didn't end there.

● To help ship larger and bulkier items: Sometimes, larger objects need to be shrink-wrapped together to remain intact during shipping. One of the most common products to involve shrink-wrapping is furniture that comes in the pre-assembled form.

● To protect products from exterior elements: valuable items in storage or on shelves should be protected to preserve the new look of a product.

● Tamper Evident Packaging: Everyone wants to be sure consumable products have not been tampered with. Shrink wrapping is a way to ensure products arrive the same as when leaving the production facility.

● Branding and Readily Available Packaging: Most heat shrink wrap is available in clear. The clear packaging allows many options for branding. Printed boxes and labels are the easiest way to quickly brand products being shrink wrapped. Some companies have enough volume to justify a printed shrink wrap for branding. Shrink sleeves are really popular printed shrink wrap materials. They can change the color of the bottle and feature vibrant and eye-catching graphics.

More Recent Developments

Many products for Amazon fulfillment and other companies are required to be double sealed. The seal for a bottle would be something around the bottle cap and then the bottle placed in a sealed package. Poly bags are common but can lead to excess packaging unless companies keep multiple bag sizes on hand. Centerfold polyolefin shrink wrap has become a favorite for many online sellers to provide the extra seal in case of product breakage. We recommend a 100 ga crosslinked polyolefin shrink film for double seals to ensure extra protection.

Several companies are working on ways to make shrink wrapping more environmentally friendly. One popular option was biolefin shrink film. It was supposed to decompose within months of disposal. It also overcame the obstacle of storage without degrading. Over time, problems arose with the dependability of the film by some producers. Since then, many shrink film producers have tried to find biodegradable shrink wrap options that do not have storage obstacles to overcome but can decompose within an adequate time.

Conclusion

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Plastic polymers have come a long way in the past few decades, and the growth process has resulted in a fantastic technique known as shrink-wrapping. The polymers used in shrink-wrapping today are versatile and very strong, so when something is wrapped, you can count on that product being very tight until the customer decides to open it. Shrink-wrapping is a cost-effective method of protecting items and keeping them intact until they reach their final destination. When it comes to packaging various food items, it provides numerous other benefits, not the least of which is its ability to preserve and protect.

If you're interested in learning more about the shrink-wrapping process and the items that can accommodate the process, the right company can help you get started. We have everything for shrink wrapping from starter to fully automatic machines and everything in between. It is easy to learn more about the shrink-wrap process because it's straightforward. We can help you whether you've never had a shrink-wrap machine or if you want a newer and more updated one, and we'll make the entire process easy.

 

Packaging material

A pallet loaded with corrugated fiberboard boxes being stretch wrapped

Stretch wrap or stretch film, sometimes known as pallet wrap, is a highly stretchable plastic film that is wrapped around items. The elastic recovery keeps the items tightly bound. In contrast, shrink wrap is applied loosely around an item and shrinks tightly with heat. While it is similar to plastic food wrap, it is not usually made of material rated as safe for food contact.

It is frequently used to secure pallet loads to one another but also may be used for bundling smaller items. Types of stretch film include bundling stretch film, hand stretch film, extended core stretch film, machine stretch film and static dissipative film.

Materials

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The most common stretch wrap material is linear low-density polyethylene (LLDPE), which is produced by copolymerization of ethylene with alpha-olefins, the most common of which are butene, hexene and octene. The use of higher alpha-olefins (hexene or octene) gives rise to enhanced stretch film characteristics, particularly in respect of elongation at break and puncture resistance. Other types of polyethylene and PVC can also be used. Many films have about 500% stretch at break but are only stretched to about 100–300% in use. Once stretched, the elastic recovery is used to keep the load tight.

There are two methods of producing stretch wrap:

• Blown: the resin is melted and extruded through an annular die, it is air-cooled. This is a slower process but provides for higher cling quality. Blown film is not a consistent extrusion process, leading to inconsistencies across the film web. The cost of production is also higher due to the quantity that can be produced per hour.
• Cast: the film is extruded through a slot die, then passed over cooling rollers. This makes the cooling process quick. Cast films are more consistent and have better performance characteristics. The cling quality is not as good as blown but more can be produced in an hour with lower costs.

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

Functions

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In pallet unitizing, stretch wrap can have several functions:

• Improved stability of products or packages, forming a unit load
• More efficient handling and storage of unit loads
• Some degree of dust and moisture protection
• Some degree of tamper resistance and resistance to package pilferage
• Some degree of sun protection (UV stretch wraps)

Making sure boxes stay on the pallet and properly aligned is an important consideration in warehouse distribution, especially as the demands for increased throughput continues to rise.

Stretch wrappers

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An automatic rotary arm wrapper An automatic rotary ring wrapper

Stretch wrappers are devices used to apply stretch wrap. There are many types of stretch wrappers:

• Manual (or hand) wrappers:
  • Extended core: An extension of the film's core serves as a handle for wrapping; this type of wrapper offers little stretch control and is hard on hands.
  • Mechanical brake: A simple structure supports a film roll and a mechanical brake system provides resistance creating stretch of the film.[1]
  • Pole wrappers: Similar to the mechanical brake system, but the roll and brake are at the end of an extended pole, creating an ergonomic design which eliminates the need to bend to wrap the bottoms of loads and strain to reach the tops of loads.[2]
  • Prestretch hand wrappers. One-hand-operated wrapping tool with a mechanical pre stretch achieved by two guiding rollers for the stretch film with different speeds.
• Semi-automatic wrappers:
  • Turntable wrappers: The load to be wrapped sits on a turntable which spins the load relative to the film roll, which is housed in a carriage which can move up and down a fixed "mast". Stretch is achieved by rotating the load at a faster rate than the film is fed.
  • Orbital wrappers: The film is housed in a carriage on a vertical ring, the load is fed horizontally through the eye of the rotating ring, applying film to the load. A variation of an orbital stretch wrapper is a horizontal ring system, in which the load remains still while a horizontal ring is rotated around the load and moves up and down vertically relative to the load, similar to a rotary arm stretch wrapper.
  • Rotary arm wrappers: In this system, the load remains still while a rotating arm turns around it wrapping the load. This system is used for light loads or for speeds which would otherwise cause the load to topple due to high rotation speeds.
• Automatic wrappers: Automatic wrappers are generally a variant of a semi-automatic system. Automatic wrappers include a conveyor system to automatically load the wrapping machine and automatic systems to apply, seal, and cut the film.
  • Turntable wrappers: The load to be wrapped sits on a turntable which spins the load relative to the film roll, which is housed in a carriage which can move up and down a fixed "mast". Stretch is achieved by rotating the load at a faster rate than the film is fed.
  • Rotary arm wrappers: In this system, the load remains still while a rotating arm turns around it wrapping the load. This system is used for light loads or for speeds which would otherwise cause the load to topple due to high rotation speeds.
  • Rotary ring wrappers: The film is housed in a carriage on a horizontal ring in which the load remains static while the horizontal ring is rotating around the load and moves up and down vertically relative to the load, similar to a rotary arm stretch wrapper. The rotary ring technology is really a more balanced system with less wear and maintenance than the other available wrapping technologies. These wrappers are capable to reach the highest production capacities (up to 160 pallets per hour).

See also

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