Customers can count on our extensive knowledge of adhesive release liner technology to select the proper pairing with adhesive and film or facestock, to supply the performance required for any labelling situation. The release liner is just one part of the total solution for high-quality custom adhesive and pressure sensitive products.
Ameri-Cal has decades of experience providing the right release liner/adhesive matchups for use in a variety of different industries, such as automotive, electronics, medical and more. Just as there is no one-size-fits-all adhesive, release liners offer different features and benefits that can supply a clean and well-timed release for optimal performance and less waste.
Some of the factors that determine proper selection include:
- Processing parameters (flat lay or roll)
- Application method (high or low speed)
- Potential moisture exposure
The method of processing or printing on labels could require a particular weight or type of release liner paper.
Lay Flat Liners
Adhesive release liner paper in sheets is the style best suited for flatbed or clamshell printers. These require a flat lay release liner of 88-96 lb. base weight of the paper. This type of thicker paper is often selected for more durable labels, intended to last the lifetime of a product.
Lighter weight papers benefit converters who print by the roll. The lighter weight paper and silicone layers are thinner, offering more productivity per roll for a greater profit margin, when selecting a 3 mil thickness for example, compared to 7 mil.
Adhesive release liner rolls offer greater versatility for printing variable information such as serial numbers in a sequence, where the numbers change with each label printed.
Depending on the application, customers can choose between paper or polyester adhesive release liners. Polyester liners are moisture resistant, unlike paper liners that can curl or rip when exposed to moisture.
Polyester adhesive release liners are available in 1.5 mil to 4 mil, with 3 mil as the most popular.
Polyester liners are preferred when doming is requested. Doming or lensing is a process of adding a urethane layer on top of the label. This urethane layer adds a shiny, protective and raised surface on the front of the label. In addition, polyester eliminates the possibility of paper fibers or lint breaking the surface tension of the urethane and ruining the dome.
Doming is one technology used for applications that require a more aesthetic look. Labels related to branding or corporate identity often use doming to support the value proposition of the brand. Doming is a popular technique on labels or branding on trucks and automobiles, appliances and other home goods and even apparel, like a sports jersey. These would require polyester for the adhesive release liner stock base.
Specialty Liner Considerations
Traction backed liners
Polyester liners with traction are the prime choice for machines with a rotary die feed that relies on sheets, sort of like a copying machine. Both rotary printers and flat-bed printers require a flat lay release liner sheet, but a rotary printer needs a liner with some traction to avoid slipping and remain in register for clean and clear printing.
In addition, traction backed liners help prevent stacked polyester sheets from blocking. The traction allows a bit of air or distance between sheets. It also helps prevent scratching the front of the sheets when they are stacked.
Anti-block or non-blocking coating
A low surface energy (LSE) coating, which is actually more economical than silicone, can help prevent adhesive ooze in stacked, printed labels. When labels are diecut and stacked, an aggressively applied adhesive can overflow and cause the stacked sheets to stick to each other, causing the decals or labels to separate from the liner.
Double Sided Liners
Applications that require a double liner have a few requirements to ensure a proper outcome.
First, double liners work best in lay flat processing, in sheets. Ameri-Cal carries this style in both paper and polyester stock.
In addition, this style must have a differential or strength ratio of at least 3:1. If it doesn’t, the adhesive will not work properly. With adhesive on two different sides, unless one side’s adhesive is stronger than another, it creates what is called “adhesive confusion.” This differential allows for smooth unwinding without the adhesive picking up.
The density of the paper pulp in the paper stock for the adhesive release liner is a hidden factor that determines the quality of the end product. The denser the paper pulp, the less the label compresses under further processing like printing or cutting.
The less dense the paper pulp, the more compression is produced during processing, causing label springback. This springback can cause liner separation and ruin a project. Dense paper pulp provides a cleaner cut and can impact the longevity and lifespan of the knife or cutting blades.
At Ameri-Cal we evaluate the density of the paper pulp to produce a quality adhesive release liner.
There are myriad ways to cure silicone for adhesive release liner applications. Ameri-Cal understands the relationship between cured silicone and cured release agents in the silicone that allows us to pinpoint the properties that meet your CTQs (critical to quality standards).
Ameri-Cal proactively adjusts with the latest technologies in adhesive release liner materials. We work hand-in-hand with the technical development teams of release liner manufacturers to ensure the quality and technology of our products are state of the art. Contact us for your next project requiring a custom approach to your labelling needs for pressure sensitive products.