How do shrink wrappers work

In addition, each one can be co-extruded into multilayer films with different additives in order to create distinct barrier properties that promote shelf life or a particular appearance. Shrink films can be formed into flattened roll stock, bags, overwrap, banding, and tubing. They can add a form of tamper-resistant protection to packaged goods. Here's a breakdown of the three main shrink film types and their common uses:. Given its lightweight nature, inexpensiveness, and multi-purpose capabilities, PVC was once the most commonly used shrink packaging material in the world.

It has since given way to polyethylene PE and polyolefin POF for a number of reasons, including the health dangers posed during creation and incineration, as well as its level of sustainability. In its rigid form, PVC is durable and used in such applications as construction projects and houseware products. In terms of packaging, PVC is applied to both rigid constructs like blister and clamshell packaging and flexible ones like shrink film and bagging.

PVC comprises a combination of three elements: carbon, hydrogen, and chlorine. Due to the strong, harmful odors that are released when heated, it is recommended for use in well-ventilated facilities. In fact, it is banned altogether in some countries because of its chemical composition and the harmful byproducts released during creation and decomposition.

Even in countries where it is legal, brands that are committed to corporate and social responsibility have banned PVC in their own packaging process. For example, the Walmart Sustainability Playbook specifically targets PVC reduction in packaging materials used by the manufacturers of products sold in their stores.

A notable downside to PVC is its reaction to hot and cold temperature changes. It can become brittle under certain low temperatures and subject to wrinkling under certain high temperatures. Its resistance to tearing after being punctured is on the higher side, but its resistance to being punctured is on the lower side.

This type of film is not ideal for bundling multiple items together, given its more brittle nature after shrinking. PVC is also known to leave carbon deposits on the sealer, which means proper and regular maintenance is required for consistent operation. It offers preferential orientation shrinks in only one direction and exerts low shrink force on a product. It is a 3 recyclable material, which means it is unable to be recycled in most cases.

PVC is leveraged in a number of applications in the building and construction industries, as well as the healthcare, electronics, and automobile sectors, among others. Polyolefin shrink film is extremely durable and versatile, making it a premium option. POF materials are available with different characteristics. One option is cross-linked film, which provides high-tensile strength and incredible clarity for high-speed packaging applications. Cross-linked film also prevents buildup on the sealing components of your machinery.

This decreases roll change-over and increases both efficiency and productivity. POF shrink film has excellent puncture resistance and seal strength, which helps protect irregularly shaped items throughout its supply chain lifecycle. POF is available in thicknesses as low as gauge. The versatility and reasonable cost that POF lends to multiple machines and packaging forms make it a go-to option for protective packaging manufacturers of any size.

In some instances, POF film requires the addition of perforations, or tiny holes, before application. These holes allow air to escape during the shrinking process in order to produce a smooth package with an even shrink surface and no air pockets. Pre-perforated shrink film is available by many suppliers for this reason. With its superb clarity and glossy shelf appearance, this shrink film is optimal for consumer products for which presentation is critical.

POF is durable and less affected by temperature changes. It features excellent tensile strength and propagation to tear, and it has the ability to shrink quickly and completely, resulting in a finished good as soon as it comes out of the shrink tunnel.

Common uses for POF shrink film include toys, games, candies, books, foods, most retail items, and any consumer product where appearance is important. When we say it's versatile, we aren't kidding! Depending on your need for barrier layers or MVTR, additives can be combined to give you exactly what you need with this packaging film. Polyethylene is a type of polyolefin, meaning it is a single monomer film that is formed with the addition of ethylene during polymerization. PE is used in several forms of flexible protective packaging, including shrink film and stretch film, performing very differently for each.

With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber. HDPE is commonly recycled in both its rigid form e. Due to its exceptional versatility, it is the most widely utilized of plastics and is applied to a wide spectrum of products, from hard hats to milk jugs.

Common uses include beverage bottles, personal care products e. The bread bags and thin plastic produce bags provided in grocery stores are made from HDPE, as are cereal box liners. It's also used in more heavy-duty stretch-wrapping situations, such as bundling produce on farms.

It usually comes on a roll similar to other films but is more of a net that offers breathability to the products it wraps. While similar to high-density polyethylene, LDPE has a lower density as the name suggests.

This means that it has less mass compared to its volume. LDPE is highly resistant to impact, moisture, and chemicals. LDPE is commonly used in applications for which heat-sealing is necessary, as well as in the manufacture of some flexible lids and bottles, and in wire and cable applications. This is one of the most commonly used films in the packaging industry.

It doesn't shrink as well as other films, but is great for stretch-wrapping pallets and protecting heavy loads in transit. This film is most often confused for shrink films like a plain polyolefin because it is visually similar on the roll. Nonetheless, it performs very differently for packaging protection. The benefits of using Low-Density Polyethylene over other forms of shrink film packaging include added strength and durability for heavier, larger items e.

These films are also printable. Clear graphics can be added while maintaining the image and the strength required. These thicknesses are used in Marine industrial applications, like shrink wrapping a boat for storage. Shrink film and stretch film are often confused, as they look very similar and as mentioned above, can both be made of polyethylene.

However, they each perform very differently:. When PE is used in a shrink film application, it is loosely placed over a single item or multiple items around which it will shrink when heat is applied, creating a tight, tamper-resistant seal of protection. When PE is used in stretch applications, it is formulated differently to be able to stretch around items. As to who invented shrink wrap, its provenance is murky.

Lowry, John Dreyfuss and John W. Harrison of Winchester Massachusetts in the US. Shrink wrap is made of plastic. What type of plastic is shrink wrap made from depends on how it is to be used, but typically it is made from plastic polymer — usually low density polythene or, sometimes, PVC.

It can also be made from biaxially orientated polypropylene, a more complex version of polythene. What they all have in common is that they are made of long chain molecules that, in their natural state, tangle round each other like spaghetti.

Shrink wrap can be used to cover all sorts of things. To use shrink wrap, you need the right plastic shrink wrap film and the right equipment: usually at the very least a heat gun. You may also need a frame to hold the film. When shrink wrapping pallets of goods, individual shrink wrap pallet covers are available if you want to cover standard sized pallets of goods — available as sheets and on rolls. For more awkward shapes, this protective packaging comes in rolls and sheets, which can then be wrapped or put over the goods and then heated, often with a hand-held heat gun.

So, how does heat shrink wrap work? As we have seen, heating pre-stretched polymer sheets allows the ordered molecules to move about and re-order themselves as a tangle of molecules, occupying a much smaller volume and causing the sheet to shrink. In practice, this means that putting, say, a shrink wrap pallet cover over a pallet, and heating it the cover will start to contract and pull tight over the goods.

How to use a heat gun for shrink wrap is perhaps the hardest part of the process. See the video below for different ways to utilize shrink wrap bags.

A gift basket shrink bag can be inserted with the open end facing down at the bottom of the basket. A heat gun or hairdryer applies heat to the bag to conform to interior contents. Because the opening is at the bottom, a heat sealer is often not used. See the video below to view how to use gift basket shrink bags. Pallet Length in. Pallet Width in.

Pallet Diagonal Value in. Height in. Width in. Film width needed in. How To With Images. Choose The Right Machines and Materials. Proper Measurement. Sealing Open Film Ends. Applying Heat. How to Shrink Wrap Videos. How to Use Shrink Wrap Bags.

How To Shrink Wrap: with Pictures 1. Insert products into the heat shrink wrap material of choice. However, the size that a polymer shrinks is completely dependent on its kind. For instance, the PVC film for shrink wrap is able to shrink for up to fifty percent, whereas the polyolefin film for shrink wrap shrinks a little less, despite being a firmer sealing option than PVC.

It is preferred over other methods of wrapping as it ensures the safety of the products and protects them from any dampness, bright light, and it also keeps the object secure during transportation. Shrink wrapping is perfect for wrapping CDs which can be seen from its covering; it is also perfect for food items and pharmaceuticals.

It is also popular for its economical packaging. At first glance, the polyolefin film for shrink wrap might look quite thin, and while it is the thinnest film available in the market, its strength is no match. These are only a few of the many multiple factors why the shrink wrap film is the best alternative to any other packaging method. The way a shrink wrapping machine works is dictated by its kind.

The chamber-sealer, L-sealer, and side sealer are the three most common types of shrink wrapping machines. The chamber sealer, as the name suggests, puts the items through a chamber or compartment, where the film of shrink wrap is prepared to be packaged around the object.

This chamber is warm enough so that the shrink-wrap is compressed and forms a secure coating over the object. The duration of this process varies depending on the width of the plastic. This particular type is manufactured to cater to bigger sizes of shrink-wrapping material. If you have an automatic L-sealer at hand, set it up, simply plug it in and put your desired object into the machine.

Shrink film bends down the two bars to make a pouch-like opening through the crinkle of the folds to allow your objects to pass in. The shrink film has three other sides that should be firmly sealed once your object is safely placed inside the crease. The L-sealer can identify when an item is placed completely inside the machine and when to coat the objects with the shrink film.