What Is a Label Release Liner?

What is best option for your product labels?

Label liner materials

There are a variety of different release liners available for labels and stickers. Depending on your label application and specific product features, there might be an option that works better for you. The most common release liner materials are paper or PET film.

If your labels are going to be used in an automatic labeling applicator they must have the right liners to hold up in the machine. Otherwise, it can result in more waste, company downtime, and material shortages.

PET release liners

PET liners are primarily important for high-speed automatic labeling machines. They are made from polyester film, which is thinner than paper liners so you can roll more labels on each roll. This reduces roll changes during high-speed or large-volume label applications, and it also reduces waste. Since the rolls can be smaller, this can also save storage space and shipping costs.

PET release liners are also ideal for things like labeling beer cans that require a wet application. They generally have fewer breaks on automatic machines than paper liners, which saves time and money.

Paper release liners

Paper liners are one of the most common release liners and the most economical. aper release liners have a silicon coating to prevent the label adhesive from sticking to the paper underneath below. That way you can separate your label and liner easily when ready for application.

They offer good tensile strength and won’t break when converting into labels or being wound on a label applicator. While they are strong under tension and can perform on high-speed packaging lines we don’t recommend them for things like wet applications.

Avery WePrint offers a clear film PET liner that is ideal for things like beer can labels or you can order our standard paper liners available on most labels and stickers.

If you are thinking about switching your release liners or need any help, contact us at (800) 942-8379. As always, we can also provide samples to help you compare your options.

What is a Release Liner? Meaning & More

There’s more to your labels than what your customers see. Every label is made up of multiple components that play a specific role. While most consumers will see your label material or decorative elements, there’s one key component that makes sure your labels get to where they need to go: the release liner.

What is a Label Release Liner?

To get to the bottom of a release liner’s meaning and role, it’s important to understand how a label is constructed. These are the four main layers of a label from top to bottom.

As you can see, the release liner serves as the base layer for any roll of pressure sensitive labels. This release liner is a thin sheet with a silicone layer that allows adhesive to release the roll so that it can be applied to another surface. If it weren’t for the release liner, also known as a carrier, your labels would simply stick to each other or something else before you could transport it to the next application.

The Different Types of Release Liners

Like label materials, there are different types of release liners available for use. Each of these carriers have different advantages depending on your applicator and other product factors. While there are a variety of options, there are three types of release liners that are common for product labels.

PET (polyester)

Calendered Kraft paper

Polykraft paper

PET release liners

A PET release liner is made with polyester film to create a carrier that’s extremely smooth. A major advantage of PET release liners is that they don’t break as easily as a paper liner. That strength makes PET release liners a great choice for high-speed applicators.

Another benefit of PET release liners is that they’re great for wet applications. For example, beer cans are typically soaking wet by the time they reach the labeling line, so that added durability is a major positive for any adverse applicating environments. PET is also thinner than the usual release liner papers. As such, a standard 1.2 mm PET release liner will allow you to get more labels on a roll and take up less space during shipping and storage.

Calendered kraft paper release liners

While film release liners have their advantages, paper carries are still extremely common for labels in multiple industries. Super calendered kraft (SCK) papers are typically bleached white and are commonplace in the U.S. as many applicators are made to accommodate papers.

The reason why businesses commonly turn to SCK release liners extends beyond paper being an old standby for label carriers. A paper being “calendered” means that it’s polished, so an SCK is smoother than regular paper liners. That smoothness and the ability to work with the majority of applicators makes SCK a go-to option for product labels.

Polykraft release liners

A polykraft release liner is essentially a mid-point between PET and paper label carriers. Polykraft is a brown, unbleached paper that’s a little thicker and heavier than standard kraft papers. This extra heft and thickness is because polykraft has a very thin layer of polypropylene married to the paper.

The advantage of Polykraft is that the layer of polypropylene makes the material more stable and sturdy. These qualities help with moisture barriers while still allowing companies to invest in paper liners. As such, Polykraft is typically used in wine labeling and other industries that are used to paper release liners, but still need that added stability to deal with moisture.

How to Identify the Right Label Release Liner

While there are multiple label release liners available, there are a few different factors that can impact which one is best for your needs. To identify the right carrier for your labels, you’ll want to weigh the following considerations.

Your label applicator

The biggest factor in which release liner you should use depends on how you’re going to apply those labels. An applicator reads the gap between labels to know when the applicator should dispense a label. Once the sensor reads a gap, it will dispense a label so that it catches a can, bottle, or any other container. However, the wrong release liner can lead to label application issues.

Simply put, some applicators aren’t made to read clear liners. New applicators are built to accept clear release liners, which means PET carriers shouldn’t pose problems. However, you would need to opt for SCK, Polykraft, or some other opaque release liner if your application process isn’t made to handle clear carriers.

Environmental factors

The applicator isn’t the only potential challenge during the application process. You also need to make sure your release liner works with your applicating conditions.

Different application environments pose certain problems for your release liners. Wet conditions are the biggest issue, especially for paper carriers. If a beer can or some other container is soaking wet, that can cause carriers without enough moisture resistance to tear. As such, you’ll need to invest in a PET release liner or another solution that can hold up to your applicating environment.

Clear labels

Some liner issues are less obvious than others. While the carrier is removed before your labels are applied, it can still have a visual impact on clear labels if you’re not careful.

If you want to use clear labels, its best to use some form of film release liner. The reason for this is that running a clear label on a paper liner can make the label look cloudy. This cloudiness occurs because the label adhesive takes the shape of the carrier. Even a super calendered paper has small fibers that can impact the adhesive. Because of this, it’s best to use a PET release liner that has no imperfections and will enable true clarity.

Invest in the Perfect Labels from Top to Bottom

While they don’t end up on your products, different types of release liners play a pivotal part for your labels. That’s why Blue Label strives to provide the perfect labeling solution for your products. Our experts work with you to uncover any opportunities and potential issues to make sure every layer of your label is perfect for your needs.

Ready to invest in the right labels for your products? Contact us today to talk about your next label project.

Release liner

Roll of die-cut pressure-sensitive labels on a release liner

A release liner or release paper is a paper or plastic-based film sheet (usually applied during the manufacturing process) used to prevent a sticky surface from prematurely adhering. It is coated on one or both sides with a release agent, which provides a release effect against any type of a sticky material such as an adhesive or a mastic. Release liners are available in different colors, with or without printing under the low surface energy coating or on the backside of the liner. Release is separation of the liner from a sticky material; liner is the carrier for the release agent.

Industry segmentation

Globally there are between 400 and 500 companies involved in making or dealing with release liner products on an industrial scale. In general there are two types of companies which are manufacturing release liner.

Liner producer

An adhesive bandage with a release liner partially removed

Commercial coating companies deal with a lot of different end uses of this industry. They provide unique solutions to their customers, based on a wide variety of substrates and an endless combination of release agents with specialized properties. Commercial coaters usually do not make finished products, just the release liner itself and then their customers will coat a sticky material on this liner and then apply the end product to it.

In-house producer

An in-house producer makes the release liner and uses it internally to manufacture the final product. In-house producers are typically focused on a very narrow range of products e.g. labels or tapes. They use a limited amount of substrates and release materials, which are specialized for their end applications.

Liner materials

As liner material, the industry is using a wide variety of so-called substrates, which are the carrier materials of the release agent and which is needed to transport a sticky material from the manufacturer to an industrial or private end user. Typical liner materials are:

Paper

SCK - Super calendered Kraft paper, typically used for labels in the USA

Glassine - Is also a SCK paper but typically with a polyvinyl alcohol (PVOH) top coat, typically used for labels in Europe

CCK - Clay coated Kraft paper or also just called coated paper

MFK - Machine finished Kraft paper, which is the paper as it comes from a standard paper machine

MG - Machine glazed paper which is a paper which has been glazed, e.g. on a Yankee cylinder of a paper machine

Plastic film

Plastic films in general are made out of plastic resins by a plastics extrusion process and can be made out of one single type of plastic material, a blend of different plastic materials or multilayered coextrusions. Providing them with unique and adjusted features for the application that they are targeted for.

Others

Poly coated Kraft papers, which are typically MFK papers which have a polyolefin coating on one or both sides, to make them very smooth, moisture resistant and dimensionally stable.

Poly coated BO-PET film, which is a BO-PET film that has been coated on both sides with a polyolefin material. This way the tough and dimensionally stable PET film is combined with cheap polyolefin resin which makes the film a better carrier web for specialty applications.

Commonly used release agents for release liner can be crosslinkable silicone, other coatings, and materials that have a low surface energy.

Applications

There are probably hundreds of different applications, where release liner materials are being used. Such as