Innovative Barrier Options Extend Product Shelf Life And Build Brand Loyalty

What turns a first-time buyer into a repeat purchaser? Visually appealing packages that offer convenience are important, but product freshness also plays a critical role in brand success. Brand owners seeking the latest film and rigid container technologies developed specifically to extend shelf life and enhance product freshness will find a multitude of options at Pack Expo International 2006, being held October 29 to November 2 at Chicago's McCormick Place.

Improving barriers and convenience has enabled flexible packaging, like stand-up pouches, to grow in areas traditionally dominated by rigid formats.

Sponsored and produced by the Packaging Machinery Manufacturers Institute, Pack Expo International 2006 will highlight an array of packaging materials and containers as well as the latest developments in packaging machinery. This article covers recent trends in foils, foil alternatives, barrier films, and related packaging elements that represent a sampling of products that will be on view at the Pack Expo show this fall.

Alternatives to foil

Aluminum foil has long been a reliable constituent of moisture barrier films. The aluminum foil itself has excellent barrier properties, blocking both moisture and gas transmission, and considered by many to be unmatched by plastic films to date. However, as pointed out by Eric Bartholomay, product development manager for Toray Plastics (America) Inc., foil tends to crease when flexed, as happens in the course of case packing and shelf stocking of pouches.

"Foil suffers from deadfold," Bartholomay says. "It creases with handling, and that leads to a less-than-attractive shelf presence. Creasing also can lead to pinholes in the thinner foil gauges that are common in food packaging. Once the foil has pinholes, its barrier is breached, and its effectiveness falls beneath that of film."

Toray recently introduced a line of PC metallized propylene films that are specifically designed as replacements for foil laminates. Earlier this year, for instance, Unilever chose the new Torayfan® PC1 film to replace the traditional PPFP (paper-polyethylene-foil-polyethylene) packaging used for its popular Knorr and Lipton products. The choice followed a six-month trial that demonstrated that the new film delivered superior barrier protection that would enhance brand image while also reducing packaging costs.

ExxonMobil Chemical Company has also developed film designed to replace foil laminates. The company's Very High Barrier Metallyte™ film is a new generation of Exxon's Metallyte OPP film that features enhanced barrier protection, making it an attractive replacement for aluminum foil. Metallyte 18XM383 provides among the best barrier materials available in uncoated metallized films and it protects sensitive products against moisture and aroma loss or uptake, oxidation, ultraviolet light degradation, and flavor loss.

Unilever has replaced its traditional PPFP (paper-polyethylene-foil-polyethylene) packaging with new Torayfan® PC1 film for its popular Knorr and Lipton products.

Foil and metallizing options

Ed Verkuilen, marketing manager of Rollprint® Packaging Products Inc. explains that some products need a protective barrier like that provided by aluminum foil or metallized polyester film composites but can't use either because the metal can potentially interfere with anti-theft devices currently used in retail packages and may cause similar problems with future technologies such as radio frequency identification (RFID) transmissions. As RFID inspection and inventory use increases, this can become a significant problem. Rollprint's alternative is ClearFoil®, a trademarked line of clear, high barrier films that do not contain any metal, as oxides of the aluminum actually provide the barrier properties.

The original ClearFoil film offered a barrier approaching that of 1 mil foil, but in an absolutely clear film, allowing package users to view the contents. The ClearFoil line of flexible, ultra-high barrier, transparent laminations now includes dozens of products that meet a wide range of barrier requirements and use numerous methods, including silicone oxide (SiOx) and aluminum oxide (Al2O3), to achieve the unique barrier requirements of individual customers in a variety of industries.

"People sometimes hear 'aluminum' and confuse the aluminum oxide coating process with metallization that utilizes vaporized aluminum, but it is not the same process," Verkuilen says. "Aluminum oxide deposition incorporates a very thin layer (only a few angstroms thick) of aluminum oxide, which provides a clear film with excellent barrier properties without the use of metal."

At PACK EXPO International 2006, Rollprint will also exhibit its new ClearForm™ formable film, a proprietary copolymer blend that offers outstanding toughness and exceptional clarity, along with an unusually wide thermoforming processing window. As an alternative to traditional bottom webs such as EVA/Surlyn/EVA, nylon coextruded films, and other polyethylene-based polymeric blends, it provides equal critical performance benefits at reduced cost.

Opening and reclosing

While barrier films are designed to protect a product while its packaging is intact, eventually packages have to be opened. As consumers demand more and more convenient packaging, that act of opening—and increasingly, reclosing—has grown to be something of a challenge for barrier package developers. How do you create a package that protects against moisture and oxygen ingress, yet is also convenient to open and reclose?

"The film provides the barrier," explains Robert E. Hogan, director of international sales and marketing for Zip-Pak, a division of Illinois Tool Works. "In most cases, to gain the advantage of easy-opening convenience on this type of packaging, the zipper is either below the barrier, which has to be opened to access it, or the barrier ends below the zipper and a hermetic seal has to be broken to use it."

However, Zip-Pak has developed a new zipper that incorporates a seal in the zipper flange. If a packager wants to provide an easy-open feature on a barrier package, and accessing the zipper necessitates the film being laser scored or perforated, the seal maintains the barrier that would be compromised by the score or perforation. The process of forming the package is also new, as the seal has to go around the ends of the zipper profile as well as below it.

"We deliberately engineered the peel-seal opening force to be relatively light," adds Hogan. "No more than two to three pounds, which is enough to maintain the barrier but is easy enough to open, offering consumers convenience. Incidentally, it also offers a tamper-evidence feature." Zip-Pak also produces its popular ZIP-PAK® Slider™ with barrier protection. The slider incorporates a scored, folded connected flange below the slider profile that provides the seal.

For more information about Pack Expo International 2006, visit www.packexpo.com; phone 703-243-8555; fax 703-243-8556; or email expo@pmmi.org.