Product Reviews

Release Liner

July 12, 2011

Demand for thin, film-based products is changing the face of the release liner market.

Growth in film-based liner is being fueled by increased demand for the no-label look. (Photo courtesy of Avery Dennison)
Release Liner

Demand for thin, film-based products is changing the face of the release liner market.

Release liner doesn’t get the press and accolades garnered by a pressure sensitive label’s other components, like the vibrant colors, textured facestocks or intricate diecuts. As part of the overall construction and end use, the liner takes a behind-the-scenes role. This, however, cannot diminish its importance. A product’s supply chain relies on the liner: During the point of application, if the label doesn’t seamlessly detach from the liner while keeping its intended properties intact, product and capital can both be lost.

More than any other industry, labeling is dependent on release liner – nowhere is it used more. According to AWA Alexander Watson Associates, 51.5 percent of the global release liner market is in labelstock, with tapes a distant second at 12 percent.

And as the label industry grows and evolves, so too does the release liner market. Suppliers are adapting to the latest trends, and manufacturing products accordingly.

Avery Dennison
Tina Hannan, film product line director, Label and Packaging Materials - North America, Avery Dennison, Pasadena, CA, USA, says that film-based release liners – PET (polyester), PP (polypropylene), PE (polyethylene) – are growing at a faster pace than other standard release liner categories such as glassine, calendered kraft, and polyolefin-coated. She says, “Reasons behind the growth include an increased demand for clear-on-clear labels for no-label look applications in segments such as beer, beverage, health and personal care, and food.”

A push for improved sustainability is another market driver, Hannan adds, noting that reducing waste through thinner caliper material, lowering transportation and inventory costs, and better overall recyclability, have become chief concerns for the industry. “Also, improved productivity through increased line speeds, elimination of web breaks during printing and dispensing, and increased packaging output via more labels per standard-size roll are also influencing the market. Our customers’ drive for productivity and cost reduction/containment has increased the demand for film-based liners for these reasons. In the past, the barrier has been the basic economics of a paper versus film liner, but the steady decline of film liner caliper from 1.5 mil PET to .92 mil PET, coupled with the productivity benefits a polyester liner provides, has helped close the gap and make film-based liners a more cost-effective alternative in a growing variety of applications,” Hannan says.

“To put it a different way, a typical 2.0 mil clear BOPP film construction on a 40#BG (bleached glassine) liner versus the same construction on a .92-gauge liner is 60 percent thinner than the paper liner option. What this means is that there is 36 percent more feet per the same 12” outside diameter finished roll and 60 percent less waste going to landfills. More labels per roll helps to reduce transportation and storage space requirements, and liner waste and PET liner material is recyclable in most regions around the world. Additionally, the higher packaging output that results from fewer changeovers and increased line speeds reduces the environmental impact of each end-use package,” Hannann says.

Paper liners still represent the bulk of Avery Dennison’s release liner usage today. “Paper liner material is still the most common liner used in the variable information and prime-paper pressure sensitive label products category,” she says. “However, film-based liner material is becoming an increasingly more common liner choice for pressure sensitive paper and film products used in the beer, beverage, HPC and food end-use segments. This is the area where growth is most prevalent.”

UPM Raflatac
“The overall trend in release liner has been to downgauge in caliper,” states Patrick Goss, prime business director, Americas, UPM Raflatac, Mills River, NC, USA. “This reduces cost through material and freight savings, while improving productivity through increasing the number of labels on a reel,” he adds, noting that what’s being used varies with geography – and the facestock being converted. “In North America, 2.5 mil kraft liner remains the industry standard for use in paper on paper laminate constructions as they meet the application requirement. For film labeling, high speed bottling applications, or in demanding application environments, PET provides high reliability and has traditionally been the liner of choice. UPM Raflatac customers also have the option of polypropylene liners for paper labelstock applications. In South America, glassine liner remains popular for both film and paper constructions,” he says.

Biofore is a new industry category UPM has created to describe the future of the company. Here, “Bio” stands for future orientation, sustainable solutions and good environmental performance. “Fore” stands for forest, and the company’s position at the forefront of development. With this in mind, UPM Raflatac recently launched its new ProLiner PP30, designed to deliver increased productivity and profitability. Billed as an ultrathin, easily recyclable polypropylene liner for paper-faced labels, Goss says it sets new standards for paper labelstock productivity and profitability and offers advantages for the entire labeling value chain.

The advantages, Goss says, include a thinner construction that results in 30 percent more labels per roll compared to products constructed with a 2.5 mil. kraft liner, which enables the use of longer rolls and reduces the number of roll changes. “This robust polypropylene liner offers high-speed converting and faster dispensing with fewer web breaks. Reduced transportation and packaging costs, thanks to the thin, lightweight construction of the liner, are also benefits,” Goss says.

UPM Raflatac also features its RafCycle program. As part of the ProLiner PP30 launch, the company provides a sustainable solution to the challenge of siliconized liner waste disposal. The RafCycle program collects and reuses ProLiner PP30 waste and ensures that it is reused and recycled into PP-based materials or new products, like UPM ProFi, a wood-plastic composite used in outdoor decking materials. Participation in the RafCycle program provides brand owners the opportunity to further demonstrate a commitment to pro-environmental packaging, while capturing savings on waste removal and disposal-related costs.

“UPM Raflatac’s ProLiner PP30 products and the RafCycle program are innovations that will have a meaningful impact on the entire industry, providing both labelstock converters and brand owners with cost savings and a compelling alternative to liner waste disposal,” Goss says, “We are pleased to introduce our customers to a liner waste recycling program that demonstrates how economic sustainability can provide productivity and profitability for all participants in the labeling value chain.”

What makes a release liner work is silicone, and Evonik Goldschmidt Corporation, Hopewell, VA, USA, is a company that specializes in siliconizing substrates. Eduardo Gonzalez, market manager, Americas – Release Coatings, says that among Evonik’s radiation curable silicones, the easy release formulation is probably the most popular. “This formulation combines an anchorage component and an easy release silicone. The release obtained is very consistent and won’t age up,” he says.

Evonik offers two UV curable silicone release systems. These UV silicones are solventless and produce release coatings without the use of heat, i.e., cold curing. The current generation of TEGO RC silicone acrylate covers the complete range of release values: premium, easy, controlled, differential, and tight. “Some of the advantages of radiation curable silicones include an unlimited choice of substrates (low cost papers, all types of films including metalized), and the ability to siliconize printed surfaces with no post curing,” Gonzalez explains.

The cold and fast cure of Evonik TEGO RC silicones makes them suitable for inline converting processes, combining siliconizing, adhesive coating and printing in one pass. The ability of free radical UV silicones to cure on any substrate offers the possibility for siliconizing over print to produce linerless labels. The cold curing allows the use of heat sensitive substrates like BOPP, PS and other types of filmic materials.

“The label industry has seen recent and growing interest in several areas; among them are the use of thinner filmic materials, linerless labels, in-line narrow web production equipment and recyclability. This trend has been very evident in Europe, South America and most recently in the US with the use of thin gauge BOPP. Radiation curable silicones provide a perfect synergy for siliconizing 30µ BOPP and other heat sensitive film polymeric materials. Due to the cold curing and lack of post curing of TEGO RC silicones, it is also possible to produce the laminate/labelstock in-line using hot melts, UV and emulsion adhesives,” Gonzalez says.

Evonik’s pilot line in Essen, Germany, has a five-roll coater capable of siliconizing and adhesive coating.

Evonik acknowledges the sustainability and recyclability demands of the industry, as well as the drive to find lower cost products. Gonzelez says its radiation-curable silicones are, by nature, green: solventless and cure energy efficient (room temperature cure). “These UV silicones have been instrumental in cost saving initiatives. For example, providing the ability of companies to easily use thin film materials (downgauging), the use of low cost, alternative papers, and the savings obtained with in-line coating of silicones and adhesives.

During the upcoming Labelexpo in Brussels, Evonik will showcase TEGO RC 702, an all-new, 1-component UV curing silicone system, ready-to-use, with the photoinitiator already included. Because there is no silicone mixing required, Gonzalez stresses that it is of special interest for label printers and converters who want to capitalize on in-house siliconizing with Evonik’s TEGO RC Silicone technology. “TEGO RC 702 was tailored for labeling applications and features easy release and low zippiness,” he says.

Evonik’s global presence and availability of technical centers with pilot plants in China, Europe and the US provides customers and prospects with test facilities for conducting trials. “Evonik offers in these regions portable inerted UV chambers that can be easily installed at customer’s plant for demonstration purposes,” says Gonzalez. “All of these services are offered at no cost to our customers and prospects.”

Dow Corning
Silicone technology has changed through the years to meet customer demands for increased productivity and improved performance with an emphasis on increased line speeds, lower costs and improved quality. “Label customers have grown in silicone sophistication and are able to request specific systems to meet their needs,” says Christian Velasquez, pressure sensitive industry global market director with Dow Corning. “Silicone systems need to cure faster – often at lower temperatures, anchor to more challenging substrates and give a wider release range today than they would have needed to, even perhaps five to 10 years ago.”

Velasquez emphasizes how Dow Corning’s Syl-Off technology makes possible what was once a difficult endeavor. “In the past, coating filmic substrates was a major challenge with several trade-offs, but with Syl-Off, coating different types and grades of films – from temperature sensitive substrates to low-cost, unprimed polyester – is a proven option for increased productivity.”

The urge for faster line speeds is another trend that can help maximize productivity, Velasquez says. “As line speeds increase, so does the issue of misting at the coating head. Syl-Off release coatings with anti-mist additives are designed to cope with extreme line speeds to achieve optimum performance. This anti-misting technology allows for optimal use of fast-curing paper and filmic release coating systems,” he says.

Another trend within the label industry’s release liner market is the switch to low-platinum solutions, resulting in protection from the swings in platinum metal prices, Velazquez explains. “The Syl-Off Advantage Series low platinum, thermal-cure, solventless release coatings have the ability to enhance line speed and improve coating performance, as well as reduce platinum usage by 15 percent in many applications.

“The Advantage Series product line has the globally-proven ability to enhance line speed, improve coating performance and reduce platinum usage, resulting in protection from the unpredictable swings in platinum metal prices. In addition, these coatings offer excellent anchorage to different substrates and are compatible with a wide variety of adhesives. Plus, Advantage Series formulations are quick and easy to adjust and can help customers enhance the processing, release performance and cost-effectiveness of their current product line or pursue new market opportunities with greater confidence,” Velazquez says.

The Syl-Off 9100 series is another featured product line. Specifically designed for use on filmic substrates, it allows customers to coat many different types and grades of films – from temperature-sensitive substrates to low-cost unprimed polyester – using cost-efficient thermal-cure technology.

“The 9100 Series is not simply an alternative polymer, but an entire system of base coating, crosslinker, catalyst and additive choices that can be combined to create the best possible anchorage, line speed and release profile for a particular substrate and end-use application,” says Velazquez. “It’s appropriate for use in the manufacture of filmic pressure sensitive laminate and labelstock as well as single and double-sided industrial release films.”