How to Shrink Wrap

Shrink wrapping products for retail sales can be an excellent choice for business owners seeking a professional packaging option at an affordable price. It can be used to package anything from boats and electrical wires to thousands of different retail and wholesale products. However, many businesses may hesitate to take advantage of this opportunity because they aren't sure what the term "shrink wrap" refers to, nor what the process entails.

Here's everything you need to know to become a shrink wrap pro.

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How to shrink wrap

How to Shrink Wrap: Basics

To navigate the shrink wrap process confidently, it's often best, to begin with the basics. So, here's our simple guide to shrink wrapping, complete with pictures and video guides:

What is shrink Wrap?

Shrink wrap – referred to as ‘heat shrink wrap’ – is a plastic film that shrinks when exposed to direct heat, conforming around the product it covers to provide secure and hygienic packaging.

It is commonly used in packaging projects where the wrap needs to fit tightly around products and is popular due to its strength, durability, and lack of open seals.

Shrink wrap can be used to package and protect just about any item. Commonly shrink-wrapped products include food like frozen pizzas, retail items like books and gadgets, and even larger storage projects like household items, palletized loads, and boats can be protected with thicker shrink wrap and a propane heat gun.

How does shrink wrap work?

Shrink wrap plastic is typically bought in either a roll of film, in bags, or as tubing. The plastic film is wrapped around its contents before heat is applied when it shrinks in size and conforms perfectly to the shape of its contents.

This process occurs due to the plastic polymers that form the shrink wrap material. When we see pre-heated shrink wrap, the polymers that form the product are rigid and structured. However, when heat is applied to the film via a heat gun or heat tunnel, it causes the polymers to break their structure and move freely.

The breaking down of these polymers causes the film to condense and shrink around its contents. As the film cools, the polymers once again set but in their new shape.

As these polymers rearrange and reduce from their original straight, lengthened state, their tensile strength increases. This makes shrink wrap tough and durable to protect against tearing and piercing, keeping its contents safe and secure.

Shrink wrap maintains its transparency despite shrinking, making it perfect for retail packaging projects where consumers need to view the product.

Characteristics of shrink wrap

Shrink wrap boasts many characteristics that make it a popular packaging option. Some of the attractive characteristics of shrink wrap include:

Tensile strength - shrink wrap’s durability makes it resistant to puncturing or tearing. This is an attractive quality, protecting contents in transit, store shelves, and warehouses – especially food items that need to maintain packaging integrity for consumer confidence.

Versatility - shrink wrap is available in various formats – including rolls, bags, and tubing – and various thicknesses. This makes it ideal for use with all your products – from pizzas to boats.

Fully sealable - once sealed, shrink wrap has no open or exposed sides, providing hygienic protection for its contents. This is useful in extending the shelf life of products like food.

Resistant to odors - similarly, the thick and airtight finish of heat-treated shrink wrap prevents odors from penetrating the packaging or contaminating its contents.

Types of shrink wrap

There are many types of shrink wrap, differing in the materials and style of the packaging.

The most common types of shrink wrap include:

Shrink wrap roll

Designed to fit around any unique shape or size of the product. Rolls of shrink wrap must be used alongside a heat sealer to close open ends around the product.

Shrink wrap bags

Bags come in unique sizes and are designed to suit specific products, for example, CDs and DVDs, books and magazines, tablets, and more. Heat sealers are needed to close the single open end of the bag.

Shrink wrap tubing

Often used to pack long or cylindrical products like jars of food or candles. A sleeve of shrink wrap film is cut to size and placed around a product before a heat sealer is used to close both ends and heat is applied to conform the wrapping around the product.

The most common types of shrink wrap plastic include:

Polyolefin – Soft to the touch with many options available. Commonly used to wrap food products. Can be found in centerfold rolls, bags, and even electrical tubing.

PVC – Crinkly after heat is applied and requires lower shrink temperatures. Secure, sleeve, and cap items without direct food contact. Found in centerfold rolls, bags, tubing, pre-cut sleeves, and shrink net banding for safety seals.

Polyethylene – Noticeably thicker material requiring higher temperatures for a total shrink rate. Cases of water bottles and other drinks are wrapped with polyethylene shrink. Pallet shrink bags can wrap and protect full loads of products, and thick rolls over a six mil thickness can wrap boats and other industrial items.

Shrink Wrap vs Stretch Wrap

Shrink wrap is often confused with stretch wrap. And while the two have similarities – in the fact they’re both made from transparent plastic and provide durable packaging qualities – they are used in very different situations.

Shrink wrap is a primary packaging product designed to directly wrap its contents, providing a barrier between the product and the consumer. Consider a frozen pizza or a new bottle of contact solution – both typically come with a layer of plastic film around them to prevent the product from being touched or handled directly by consumers.

Stretch wrap is a secondary packaging solution designed to secure multiple products together. Its stretchy properties allow it to adapt to the unique shapes of larger containers or pallets and more. Stretch wrap is commonly found in many different colors and thicknesses, depending on the application.

Both types of plastic wrap protect their contents against damage, moisture, and more; however, they have different applications in packaging projects. The main thing to remember is heat shrink wrap uses heat, and stretch wrap does not.

In some instances, shrink and stretch wrap may be used together. For example, a stack of books – each individually wrapped in shrink wrap – may be organized into piles atop a wooden pallet. The stack may then be wrapped in stretch wrap to keep the items securely packed together in transit.

Benefits of shrink wrap

Shrink wrap is a popular packaging solution because of its range of benefits, including:

Protective – shrink wrap is not only tough and durable to protect against punctures or tears but is also fully sealable, providing additional protection against germs and odors.

Cost-effective – shrink wrap is typically inexpensive compared with other primary packaging materials. This is especially beneficial for those with high-volume packaging demands. Packages can be wrapped for pennies.

Branding potential – the clear and smooth finish of heat-treated shrink wrap makes it possible to view products through the film and print directly on the film for additional advertising and marketing potential. Branded labels are another affordable branding option that can easily be applied to shrink film.

Ideal for storage – shrink wrap is compact and space-saving compared with alternative primary packaging solutions, as it shrinks to conform perfectly around its contents, whatever their size or shape. Also, protecting from dust and moisture during storage.

As you brush up on the core elements of shrink wrapping, it's also helpful to have a visual reference. Here's our guide on shrink wrapping basics, complete with pictures and video guides:

Insert products into the heat shrink wrap material of choice. Bags, tubing, and centerfold film are the most popular options.

Seal open ends with a heat sealer. This step is most often completed with impulse sealers, I bar sealers or L bar sealers.

Use a heat gun or tunnel to shrink and conform the plastic material to the product.

Shrink Wrap Equipment Overview

Now that you understand how to shrink wrap, let's look closely at the equipment necessary to do the job. Here's what you'll need:

Shrink Film

Shrink film is a plastic that comes in four types:

Polyolefin
PVC
Polyethylene
Polypropylene

Polypropylene shrink wrap is the least common choice for packaging, while the other three are used extensively in multiple industries worldwide. Each material offers different characteristics, advantages, and disadvantages, which you can learn more about on our blog.

Once you've chosen the best plastic for your wrapping and packaging project, you'll also need to consider the form of shrink wrap material you'll use. You have four options: tubing, bags, centerfold rolls, and single wound (flat) rolls. Our complete range of shrink wrap products includes a closer look at each option.

Heat Sealer

The cost of a heat sealer is directly related to the seal width and desired production levels. For example, a small four-inch hand sealer is much less expensive than a large 24x32” L-Bar sealer — but efficiency is much less. Our guide to shrink wrap machine costs helps you navigate your options and determine which is best for your wrapping and packaging needs.

Heat Source

As the name suggests, the heat source is your tool for warming the shrink film after the open ends are sealed. This causes the film to shrink and conform to the product.

The heat gun and the shrink tunnel are the two primary heating elements. A heat gun is much less expensive but will work through a lesser volume of products each day. Find more information about shrink tunnels and heat guns in our guide to shrink wrap machine costs.

How to Shrink Wrap: Step-by-Step

With a firm understanding of shrink wrap basics and the equipment required, it's time to look at the process from beginning to end. Here's a step-by-step guide on how to shrink wrap:

Step One: Determining and Gathering Necessary Equipment

Effectively and professionally shrink wrapping products for retail sales requires three key elements:

The proper type of shrink film.
A heat sealer to close open ends of the plastic material
A heating source to prepare the plastic to shrink and conform to the product.

Some projects, such as gift basket shrink bags and shrink tubing applications, don't require a heat sealer. However, the majority of shrink wrapping projects do require all three projects.

Step Two: Measuring

Proper measurements will help determine the size and form of shrink film to consider, the size of the sealer needed, and the size of the shrink tunnel or heat gun. For the most accurate measurements, we recommend finding the “length x width x height” of the largest product in the project. When you choose shrink film, a heat sealer, and a shrink tunnel or heat gun capable of accommodating the largest product, you’ll be sure it will suitably wrap and package every smaller item, too.

Depending on production levels, different sizes of plastic film can reduce waste and cost. For shrink bags, multiple bag sizes and proper product measurements are essential. The same is true for tubing when wrapping products of different sizes.

How to Measure Products for Shrink Wrapping

The best bag option is to measure each product's circumference and length. The circumference is the measurement around the product at its widest point. Here are a few formulas for reference:

The formula for Centerfold Shrink Film

Width + Depth + 2 inches = Width of centerfold roll needed

The formula for Shrink Tubing

Circumference + 10% ÷ 2 = Width of tubing needed

The formula for Shrink Bags

Circumference + 10% ÷ 2 = Width of bag needed

Length + depth + 2 inches = Length of bag needed

Step Three: Sealing Open Ends

Once measurements and proper film sizes are determined, the rest is simple.

Place the product in the film roll, bag, or tubing. Close the sealing bar on the open ends of the film, approximately half an inch from the product, and make seals. This secures loose edges to create reliable plastic packaging.

Step Four: Applying Heat

Once open ends are sealed, apply heat with a heat gun or shrink tunnel. If the film balloons and fills with air when heat is used, a small vent hole may be required to allow air to escape.

Step Five: Utilization

Now that your product has been shrink wrapped, it’s safe, secure and ready for transport or storage. This wrapping and packaging solution protects items from environmental damage, including dust and debris, moisture, oxygen exposure, and more. It’s also durable and reliable, even in temperature extremes.

Additional Shrink Wrap Resources

With various shrink-wrapping applications and equipment, each process deserves its own guide. That’s why we've compiled a list of resources to help you learn how to shrink wrap, no matter your needs, products, equipment, and project specifications.

Visual Guides

Need to see the shrink wrapping process in action? We have just what you need. Here are our favorite how-to videos to help you get started:

How to Use Shrink Wrap Bags

One unique option you may consider is the use of shrink wrap bags. Affordable and user-friendly, this low-quantity shrink wrap option is best used with a heat sealer and gun.

To use shrink wrap bags, insert products into the bag and seal the open end of the plastic. Once sealed, use the heat gun to warm the bag, causing it to shrink and conform to interior products.

For example, a gift basket shrink bag can be inserted with the open end facing down at the bottom of the basket. You then use a heat gun or hair dryer to apply heat to the bag, giving it the flexibility necessary to conform to interior shapes and angles. However, a heat sealer is often unnecessary since the opening is at the bottom.

Here are a few video guides explaining the process and its applications:

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How to Shrink Wrap | U.S. Packaging & Wrapping LLC