Release liners are in the spotlight.

By Megan Wolf

It’s an important and sometimes complicated material category in label printing—release liners—one which can have a big impact in the operations of both label printers/converters and their customers, the consumer products companies.

For label converters, the substrate/release liner combination needs to provide a reliable surface so the diecut strike-through cuts the label completely, yet does not cut or weaken the liner below. This has to be done consistently over the course of a label run of thousands and thousands of times.

Once the labels get on the customer’s packaging line, the precision and consistency of this operation will quickly be seen. If a label is not diecut completely, it will not separate properly from the liner, and if the liner is weakened, the release liner may breakout, causing downtime. In either case, the customer is not happy.

Throw into this the potential for adhesive migration within the label rolls as they are transported and stored in a wide range of environments, along with any number of other potential problems, and you can quickly see that label/release liner systems need to be well engineered, many times, for the specific application in which they are used.

The importance of finishing operations in label production can never be underestimated. In discussing the use of high-tech digital tools with finishing equipment, Rotoflex’s Ron Gourlay noted that with the consistent, high-quality graphic capabilities of modern printing presses, more attention is being focused on issues impacted by finishing. This is well understood by label printers, and is summed up by Richard Adler, Jr., CEO and president of Fort Dearborn: “You never want the label to be a bottleneck in the customer’s filling lines.”

The important role provided by release liners in label runnability is one of the reasons why they need to be so well engineered. But the time spent in the spotlight by a release liner is short lived, and once its thankless job is done, it gets thrown away, back into another—yet unwelcome—spotlight. With today’s growing environmental concerns, package printers recognize their responsibility to reduce the amount of material being sent to overflowing landfills.

Don’t refuse to re-use!

In all categories of waste, there are ongoing efforts to reduce the total amount of material entering the waste stream. For release liners, it is typical to reduce the weight of the liner to the lowest possible level without causing runnability problems in converting operations. Many times, efforts to reduce release liner weight are initiated by cost reduction programs, with the effect of reducing waste levels being viewed as a secondary benefit. Obviously, efforts to reduce liner weight can only go so far.

Joe Heinemann, president of Rayven, recognizes that release liner waste is “a hot point in the industry, and there are a few ways to combat it.” One method is to recycle and reuse certain release liners in less technically demanding applications. While he says that this is not a common practice, it is being done by some converters. As an example, he notes that certain wide-web release liners that are lightly used could be recycled for narrow-web applications with the application of a new pressure-sensitive adhesive, providing a low-cost release liner.

Whether reduced in weight or recycled, the job done by release liners won’t change very much. They will remain an underappreciated, but important contributor to a large number of converting and packaging operations. n

Resources

acpo ltd. www.acpo.com
Acucote www.acucote.com
CPFilms Inc. www.cpfilms.com

Dow Corning Corp. www.dowcorning.com

Douglas-Hanson Co. www.douglas-hanson.com

FLEXcon www.flexcon.com

Innovia Films www.films.ucb-group.com
Loparex Inc. w3.loparex.upm-kymmene.com

Mitsubishi Polyester Film www.Zm-petfilm.com

Northwest Coatings Corp. www.northwestcoatings.com

Raflatac www.raflatac.com

Rayven www.rayven.com

Sil Tech www.siltechliners.com

Stora Enso www.storaenso.com