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Anyone who shops for food these days is bound to encounter a growing number of eye-popping blow molded packages intended to provide striking graphic appeal and stir the impulse to buy. The packages consist of redesigned versions of traditional plastic bottles that are nearly 100% sheathed in tight-fitting, brightly decorated shrink or stretch labels. These full-body labels can be applied to monolayer and barrier containers and are as effective for extrusion blow molded PP and HDPE bottles as for stretch-blow molded PET.

A new generation of high-performance labels that provide 360° head-to-toe coverage is what makes this packaging concept possible. Graphics are top-quality, typically with 10-color rotogravure printing, and they envelop the bottle in a blaze of color, logos, and printed information. The labels shrink into or stretch around contours, penetrate variable geometries (such as hourglass shapes), and conform to irregular features (grips or slender necks).

A dazzling example is the extrusion blow molded, 19-oz, six-layer, PP barrier bottle for Kick'rs ketchup launched early this year by Heinz North America (see cover). The intent was to launch a new line of flavored (e.g., barbeque) ketchups. For visual impact, Heinz chose a 2-mil-thick styrenic label supplied by American Fuji Seal. The label's glove-like grip accentuates the flowing lines of the bottle, complementing a design that also includes ergonomic contours to give an easy grip.

Full-Body Labels Brighten Face of Blow Molding

"This is about shelf presence, with the bottle as billboard," says Martin Matuseck, director of marketing & strategy at Pechiney Plastics Packaging in Chicago, molder of the Heinz bottle. Heinz reports strong sales and plans to use full-body labels in other categories of ketchup, a staple for which demand had long been considered mature.

"Full-body label technology promises to increase volume in blow molding," says Joseph Spohr, senior v.p. for global sales at Graham Machinery Group. At present, full-body wraps are mostly used for new-product introductions in beverages, dairy products, powdered foods, and dry snacks. Big name users include Dannon, Tropicana, Nestle, Kraft, Procter & Gamble, and the Frito-Lay Div. of Pepsico. Some analysts project demand for shrink labels growing by around 20% annually for the next five years.

Bonanza for blow molders
The current upsurge in full-body shrink-label programs is creating a tangible sense of excitement among U.S. blow molders. They report that a flood of container programs are in advanced development, though many are shrouded in secrecy. Molders hope they are seeing the first wave of a surge in demand for blown plastic containers, especially for custom bottle programs requiring intense collaborative work.

Sources expect the full-body-labeled bottle concept to catch fire in markets beyond convenience foods and beverages. Two examples—contact-lens cleaning solution and liquors—are pictured in this article. Other candidates include cosmetics, bathroom chemicals, lawn-and-garden items, and specialty motor oils and lubricants. There's also potential for replacing flexible pouches and paperboard products. In a few years, this could stimulate demand for tens of billions of blow molded bottles.

This optimism is supported by a recent study by consultant Packaging Strategies, which predicts that demand for shrink labels of all types will grow at an average rate of 20.3%/yr through 2005. Jim Insel, sales v.p. at label maker American Fuji Seal, sees dairy and beverage bottles at the leading edge of shrink-label use in blow molding.

Blow molders sense that their competitive position is improved by the new label technology. Paperboard and flexible packaging have long been able to splash high-visibility, brightly colored graphics on products like cereal boxes, candy and nut jars, multi-pack drink cartons, and flexible pouches. "Full-body label technologies promise to allow blow molders to go head-to-head where billboard graphics once favored others," comments Rich Smith, packaging product manager for extrusion blow molding equipment at Uniloy Milacron.

Shrink labels energize new integrated packages for Nestea powder (cap doubles as measuring cup), Complete contact lens solution (bundled lens cup), and Frito-Lay Doritos (chip server). Labels can offer tamper evidence or a clear window to show off the contents.

Most of the current blow molding programs that use shrink labels are high-volume applications requiring multi-layer barrier bottles in volumes of 30 to 150 million units a year. "That's good news for suppliers of continuous wheel-type machinery," claims Russ LaBelle, president of Wilmington Machinery. That view is seconded by Graham Machinery, whose wheel and linear-shuttle systems are used in programs for Dannon and Jasper Foods, respectively.

Uniloy Milacron's Smith argues that the familiar criteria used today to select equipment (e.g., annual production requirements) are likely to be unaffected by the new trend. He says linear-shuttle and reciprocating-screw equipment are strong contenders. Smith sees features currently viewed as options (parison programming and offset-neck capability) becoming necessities for those hoping to exploit full-body labels.

Gary Carr, general sales manager at Bekum America, views productivity-enhancing concepts such as "tandem-blow" versions of horizontal shuttle equipment as well suited to sleeved bottles. Tandem blowing involves double-bottle (head-to-toe) production from each parison. Carr says a six-parison, 24-cavity machine would be competitive at 70 million units/yr.

Label/bottle synergies
Bottle design is evolving to include new shapes, contours, and sizes. But those adopted so far tend to fall well within existing blow molding capability: Structures of multi-layer bottles are largely unchanged; calibrated neck finishes are rare; existing blow molding equipment is still being used.

Nevertheless, serving the new sector requires expertise and attention to detail. Designs are being tweaked to make sure bottles will withstand shrink-tunnel conditions and don't have ridges or other projections that could damage sleeve labels during application.

Johanna Foods got fresh marketing momentum for some new yogurt flavors at little extra cost by sheathing its existing injection-blow molded cups in a seven-color printed vinyl shrink label.

Uniloy Milacron's Smith sees a synergy between the improved labels and the bottles designed to show them off. Full-body labels provide daring graphics, while subtle changes in bottle shape, contour, and function increase consumer convenience.

Doug Struble, new-product manager at Owens-Illinois in Toledo, Ohio, says emphasis is being put on the ability of shrink labels to add rigidity to a package, bundle related parts (e.g., cap and bottle) into an integrated system, or provide tamper evidence.

The interplay of label and bottle design is reflected in a program by Stonyfield Farms. In early 2002, the yogurt manufacturer launched what it says is the first drinkable yogurt in the U.S. Stonyfield's reformulated, low-fat yogurt transforms a tart, thick, spoonable item into a free-flowing, smooth-textured beverage.

Kasi Reddy, Stonyfield's R&D director, says the company needed a way to convey the new product image to customers. It turned to a full-body shrink label from Sleever Canada, a unit of French-based Sleever International, and the blow molding expertise of Shelburne Plastics in South Burlington, Vt. The 2-mil, 10-color styrenic shrink label is also applied by Sleever Canada on a contract basis.

"The label is part of a system including bottle and closure," says Gene Torvend, Shelburne's president. The white 10-oz, monolayer HDPE bottle has walls designed by Shelburne to withstand the shrink force of the label. Shelburne also built the tool, including inserts that allow container volume to be changed from 8 to 16 oz (neck diameter does not vary). The tamper-evident, color-coordinated, HDPE closure was developed by Portola Packaging in San Jose, Calif.

Shrink labels are also used to securely bundle different plastic package components into an integrated system. An example is a 12-oz HDPE container for contact lens cleaning solution sold by Allergan Corp. It uses a full-body label made of Eastman Chemical's PETG to consolidate and seal the bottle together with a tamper-evident closure and an injection molded lens-holding cup that is attached to the bottle base.

Single-serve PET water containers typify the initial food/beverage applications for shrink labels. The trend could extend to billions of other food, cosmetic, household-chemical, and industrial bottles. (Photo: SleeveCo)

Easy-removal and tamper-evident features are often incorporated into the new full-body labels. A 45-oz Nestle powdered tea package uses a V-shaped perforation to permit the consumer to unzip the label from the rim of the mixing cap (part of the integrated package) down to the bottle's foot. In a lemonade powder package for Kraft, the label includes a patented perforation that follows the diameter of the bottle precisely at the joining line between closure and rim. The perforation, working with the film's orientation (low tear strength), permits consumers to break the seal and remove the label with a simple twist.

Full-body sleeve labels also act as a shield when the packager prefers that murky contents (e.g., condiments) remain unseen. In a Jasper Foods three-layer HDPE Soy Milk bottle, the black middle layer acts as a uv screen against fluorescent light that can impair the content's nutritional value. The black color is masked by a white full-body sleeve.

As in the case of Soy Milk bottle, use of a full-body label can make the aesthetics of the bottle itself less critical. One benefit may be to allow greater use of recycled resins in high-quality consumer packaging. Another potential cost saving shows up in Heinz Kick'rs bottle: The shrink label envelops the bottle, minimizing the importance of clarity. That made it more acceptable to use PP in the structural layers, while saving 30% in average bottle cost as compared to a six-layer PET bottle.

Taking the opposite tack, Nestle has adopted a PETG label on a 16-oz PET bottle for Nesquik flavored milk that has clear decorative windows to allow the drink to show.

"We've hardly scratched the surface of what sleeve technology can do," says Brett Stegmaier, general manager at Sleever Canada. He says work is under way to modify labels to impart uv barrier to dairy containers. Other projects will incorporate gas or moisture barrier in the sleeve instead of the bottle and build in anti-theft (security hologram) or traceability functions.

Shrink versus stretch
The new curve-hugging labels all use either shrink or stretch technology. LDPE stretch labels cost less than shrink labels but are still used mostly on F-style chemical bottles. However, at least one of the new dry-food containers has adopted a full-body stretch label.

More commonly used shrink labels come in two classes—roll-fed BOPP and high-shrink sleeved types of various materials. Shrink tunnels impose an additional heat history on bottles, which has the potential to distort or degrade them. Blow molders say those challenges are manageable.

Eastman's PETG copolyester shrink properties provide an edge over OPS and PVC labels, but PETG's cost is somewhat higher.

BOPP labels are printed on film roll-stock, wrapped around the bottle, and sealed to themselves with a hot-melt adhesive. Thus, bottles must have flat "pressure points" to ensure a good seal. These labels offer a shrink range of 5% to 22%, only in the machine direction. In general, their use is limited to bottles that are less demanding in contour and shape. BOPP label suppliers include AET Films and ExxonMobil Films.

Already-sleeved labels come in vinyl, styrenic, and copolyester (PETG) versions. They slip over the bottle before it enters the heat tunnel. Producing the label requires an extra fabrication step, which adds cost. They provide 50% to 80% shrinkage, only in the transverse direction. Their high shrinkage provides a glove-like fit to highly contoured and odd-shaped bottles.

Cast PVC shrink labels have long been dominant in the U.S., and still hold a 70% share. They offer around 60% TD shrink with a gentle shrink force, but packagers in Japan and Europe have switched largely to styrenics to aid recycling. Separation of PVC labels from PET bottles is problematic because the resins' similar specific gravities makes widely used flotation separation methods ineffective.

Eastman's Embrace grade of PETG is making inroads in shrink labels. The accompanying graph shows that copolyester films offer up to 80% in ultimate shrink vs. 70% for styrenics and 60% for vinyl. PETG also displays a flatter shrink curve and lower-temperature shrink initiation than the alternatives, meaning shrink performance is more predictable and faster application is possible.

Recent applications for Embrace PETG include both extrusion and injection blow molded containers as well as glass bottles. PETG shrink-label films are made by Klockner Pentaplast, with Mitsubishi Polyester Films to enter in late 2002.

Styrenic labels provide an outstanding balance of shrink properties at around 40% lower overall cost than copolyester. Styrenic labels are softer and less crinkle-prone than other types, but they can be harder to print. Some sources say they are prone to lose stiffness under humidity.

Kevin Alexander, K-Resin packaging market manager at Chevron Phillips, says the major ingredient of OPS sleeve labels is in fact a styrene-butadiene copolymer (SBC) like K-Resin. The SBC is blended with PS and special additives. A new K-Resin grade offering more controllable shrinkage will be introduced shortly.

Ticona LLC reports that its Topas cyclic olefin copolymer is a candidate for shrink labels due to its 80% ultimate shrinkage, high clarity and gloss, and high moisture barrier. The supplier plans to commercialize a shrink-label grade late this year.

Thirst for shrink labeling is taking hold in both plastic and glass liquor bottles in a range of sizes. (Photo: SleeveCo)

American Fuji Seal, SleeveCo, and Sleever Canada are integrated suppliers of a range of full-body shrink films and sleeves, as well as the high-speed equipment needed to make and apply the labels. According to Eric Fresnel, president of Sleever International in France, "The choice of label material and equipment is best done on a case-by-case basis, depending on whether the bottle is filled hot or cold, sleeved before or after filling, and other variables." According to consultant Packaging Strategies, copolyester labels will grow by 35%/yr through 2005, while vinyl will grow at 12%/yr, OPS at 10%/yr, and BOPP at 8%/yr.

John Alonso, AET Films' market development manager, notes that BOPP labels use a lower-density material and require one less fabrication step than sleeved labels, yet still offer full-body, 360° graphic capability. He suggests cost pressures could favor BOPP shrink labels over the next few years.

But others note the high cost of shrink labeling relative to paper, heat-transfer decorating, in-mold labeling, and other established techniques. Material cost per label is said to be two to five times higher than for heat-transfer and paper labels. In addition, cost of application equipment is high, and labeling speeds would have to match the established approaches.

Sleever's Stegmaier argues that sleeved shrink labels are justified only when they add value through graphics or new functionality. He sees them taking hold in premium segments of blow molding and projects a 300% increase in sleeve-label sales in the U.S. in the next four years to a total of $500 million.

"Shrink-sleeve decoration of blown bottles has great market appeal but also can make the blow molder's life more difficult," comments Marty Dennis, sales and marketing director at Smurfit-Stone's Di-Na-Cal Div., a supplier of competing heat-transfer labels. He says sleeve application poses challenges in blow molding plants where molding, filling, labeling, and leak testing are done in-line.

Challenges & benefits
"In some respects, full-body labels pave the way for a more utilitarian approach to extrusion blow molding," says Bekum's Carr. The labels tend to hide the bottle, making appearance (e.g., streaking), color, and clarity less critical. To reduce costs, bottles can often be left natural, white, or black.

Johanna Foods in Flemington, N.J., used a full-body sleeve label to give an old container a new look. The firm was able to use a proven container and existing tooling. Johanna owns the La Yogurt brand and captively injection blow molds the A-frame, 6-oz cups used for that yogurt. The company recently reformulated five top-selling flavors and adopted sleeve labels to add marketing momentum at no extra cost. It retrofitted a PVC sleeve label from American Fuji Seal to the existing bottle. The labels splashed fruit illustrations across the bottle and color-coordinated the labels to a specific flavor, like blue for blueberry.

Dry snacks have huge new potential for blow molding. Novel bottle shapes and contours can add another dimension to the look and function provided by full-body labels. (Photo: Procter & Gamble)

Shrink labels are often curled beneath the bottle base to anchor them, but that threatened to impair the prized multiple-stacking capability of Johanna's A-frame design. American Fuji Seal customized the sleeve to make sure it remained above the rim at a 1-mm tolerance.

One of the more remarkable new opportunities for blow molders is dry snacks, which until now have appeared mainly in bags or cardboard tubes. A success for shrink-labeled bottles is the Go-Snack chip line launched by Frito-Lay. The hourglass-shaped, 8-in.-tall, 2.9-oz canister uses sleeves from American Fuji Seal to provide a striking graphic appeal and to color-code five varieties. The black canisters are crush resistant and sized to fit cup holders inside cars, while a 1.25-in.-deep, injection molded "ghost" cap doubles as a chip holder.

Greg Fehn, general manager for technology at Consolidated Container Co. in Irving, Texas, which molds the Frito-Lay containers, says there was a concern about shipping product to higher-altitude localities, where atmospheric pressure is lower. A special base ensures that the odd-shaped bottles have the necessary strength to prevent them from "ballooning" due to differential pressure.

Frito-Lay's package is a four-layer structure, with EVOH on the inside next to the dry contents. That contrasts with the six-layer structure typically used for liquid contents. That structure places EVOH in the core between tie layers to minimize barrier loss from moisture absorption. The dry-snack package does not have this problem, and the four-layer structure reduces cost because expensive EVOH can be distributed more evenly in the inside layer. Additional savings came from the need for fewer extruders, a simpler die, and less tie-layer resin. As an added plus, the EVOH provides a naturally slippery surface that lets product slide out easily.

Procter & Gamble is putting its triangular, concave Torengos chips into a matching three-panel, 5.6-oz, container said to allow efficient nesting and removal of the chips. An LDPE stretch film label is used, while a ridge molded into the bottle base holds it in place. Consolidated Container, the blow molder, modified its trimming equipment to handle this container.