When choosing between film and paper release liners, it’s essential to understand their performance in various environments and their unique characteristics.
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Application Environments:
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Understanding these distinctions can help you choose the right option for your project, ensuring optimal performance and presentation.
One of the critical choices in purchasing product labels is the type of label liner, also called a release liner. Choosing paper when it should be poly, or vice versa, increases costs, delays packaging production, and hurts the bottom line.
There are two primary types of liners—paper liners and film liners. The most common film liners are also known as poly liners or PET liners.
So, which release liner is better, paper or film? There are several factors to consider.
A liner is the part of a pressure sensitive label that acts as a carrier for the label. It protects the adhesive until the label is ready to be applied. It’s also treated or coated so that the label releases easily during the application process, whether its manual or automatic.
Labels that are destined for automatic machine application must have liners that stand up to the rigors of machine application.
When label liners tear during automatic application, several things happen.
❌ There is more waste. Every machine re-start requires using labels to re-set the machine.
❌ There is more downtime at the factory. Too much downtime because of defective liners can result in charge backs from the manufacturer.
❌ There may be a shortage of labels to finish the production run. This requires costly reprints and results in additional manufacturing costs. Depending on the situation, penalties might also apply.
Machine processed labels are done on a roll. Die knives cut through the label and adhesive layers but not through the liner.
When the labels are die cut, the waste is stripped cleanly away from the label and liner as shown in the image below.
The printed, die cut labels are rolled and ready for automatic machine application.
If the setup on the die cutting is incorrect, it causes serious problems with automatic label applicators.
All knives should be set to cut through the label paper and adhesive without going into the liner. If the knife cuts too deep, it penetrates the liner, creating a weak spot.
The illustration above shows a weak spot created by the knife cutting too deep.
Each rotation of the die means there will be a re-occurrence of that weak spot throughout the label roll, any of which can cause a tear as the machine applicator runs.
There are two ways to avoid liner problems with your labels.
One – work only with label printing companies who use rigorous manufacturing standards and quality control to ensure that labels never ship with defects in the liner and label.
Two – replace paper liners with polyethylene terephthalate (PET) liners. PET, also called poly liner, is a film liner that is much stronger than paper.
Currently, glassine liner papers have about 36% of the market, poly coated kraft has about 24%, with film liners at 22% according to Label and Narrow Web. Here are the pros and cons of each.
Paper is hygroscopic, meaning that it absorbs moisture from the air or releases it, depending on the temperature, the relative humidity, and the moisture content of the paper. It is always seeking a balance. As the relative humidity and temperature changes, so do the dimensions of the paper.
This means that paper products must be properly conditioned to the print shop atmosphere prior to printing. Changes to the paper due to improper conditioning causes problems in printing, die cutting, coating, or lamination. In turn, these problems can cause stoppages in the automatic label application machinery.
✔️ PET is also hygroscopic but to a lesser degree than paper. In fact, moisture stable paper release liners are made by coating both sides of the paper with a polyethylene to inhibit moisture absorption.
Contact us to discuss your requirements of china release liners. Our experienced sales team can help you identify the options that best suit your needs.
✔️ PET is thinner than liner paper. This means the average roll can get up to 20 to 30% more labels on a roll. In turn, this reduces transportation costs.
✔️ More labels per roll means less changeover time, which increases packaging productivity.
✔️ PET is stronger and breaks less frequently than paper. This added strength means machines can run considerably faster with less downtime.
✔️ PET is better than for wet application conditions.
✔️ PET liners reduce waste volume, with liners as thin as 23 microns, or about 0.”. Glassine paper liners are typically about 50-70 microns thick.
✔️ PET is less susceptible to curl than paper. Flatness is a key element to high label applicator productivity.
✔️ PET produces less dust than paper liners, which is important in pharmaceutical, electronics, food, health, and cosmetics packaging.
✔️ Because of current paper supply problems, lead times for PET are shorter than paper liners.
✔️ PET is better for labels that are used in harsh environments or that will be exposed to the elements.
There are times when paper liners might be the better choice.
✔️ Paper is more rigid than film and is better in applications in which rigidity is required.
✔️ Paper is more sustainable and has chain-of-custody certification available to track fiber from the forest through its end use. However, film liners are catching up with improved liner recycling processes coming into place.
✔️ Paper liners are generally lower cost.
There is no single “right” choice when it comes to paper versus PET release liners. Much depends on the end use of the label along with the label application process.
We can work with you to eliminate common mistakes caused by faulty liners, and help you select the product label that’s best for your bottom line.
Call us at 818.709. or Contact Clear Print here to talk about selecting the right release liner for your next job.
Drytac explains why high-quality release liners are crucial to easy printing and installation.
Authored by D’Arcy Lewis, Technical Sales Manager, at Drytac.
When installing self-adhesive graphics, the last thing you probably think about is the remnants you throw away. However, the quality of these remnants – better known as release liners – can make a significant difference to the printing and installation process of a graphic, and the end result.
Release liners are a critical feature of self-adhesive print media. They are a key component for the delivery of the product and the application performance, but as they are ultimately disposed of they are often perceived as being of low value. That couldn’t be further from the truth. By spending just a few more pence or cents on a graphics solution with a high-quality release liner you can save yourself a lot of hassle, time and – ultimately – money.
Typically paper-based (although they can be made of Polyester/Polypropylene), release liners are usually applied during the manufacturing process of print media, including films made from PVC, polyester, polypropylene and synthetic paper. Coated on one or both sides with a release agent, they are used to prevent the sticky surface of a substrate from adhering prematurely or to the wrong surface.
There are a number of key aspects of release liners that can affect their compatibility for a job. For example, some printers use extreme heat which can shock cheaper liners, potentially causing cockling or head strikes. Using a higher-quality PE-coated liner will help the material lie flat during the printing cycle.
A thicker release liner is also required to stabilise thin materials during printing. For instance, a 50-micron/2 mil polyester would normally be too delicate, but the correct release liner enables their use.
In addition, optically clear materials require an opaque or white liner so machines can see the materials and print on them.
A good liner will also add stability during cutting, especially on integrated printer/cutters where the material is gripped by pinch rollers. These machines truly whizz the material around, so the liner has to grip to give accurate cut lines.
The weight will also influence installation; a heavier release liner will help the graphics lay flat to ensure a much easier installation process. Air release liners have added technology to make materials easy to use: tiny channels which enable air to flow and not get trapped between the material and surface, which would otherwise create bubbles. Standard PVC is not porous so this release paper technology makes graphics materials, particularly those used in vehicle wrapping, more forgiving.
Paper absorbs and disperses moisture from the air, always trying to achieve a balance. This constant change, due to the environment, can cause lay-flat challenges. Moisture stable release papers overcome this challenge. They are coated on both sides with polyethylene which inhibits the absorption of moisture and eliminates changes in the paper’s profile. The paper is then siliconized on the adhesive receptive side.
All Drytac’s products with release liners are designed to tick every box for higher quality. Only dimensionally stable base papers are used, with two-sided PE coating for moisture stability. Silicone, adhesive and paper chemistries are specially formulated to eliminate tunnelling of the media and to work with Drytac’s adhesive solutions.
For something that is usually considered waste and is thrown away, a lot of technology goes into good-quality release liners. Spending a little more on a better product will prevent printer damage, reduce downtime and speed up the installation process, making the job easier and cheaper in the long run.
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