Paperboard cartons target strength and beauty: improved paperboard materials and decorating techniques deliver functional and aesthetic value

Food & Drug Packaging, April, 2005 by Kate Bertrand

Paperboard materials and decorating technologies are creating a generation of cartons that provide enhanced physical properties, such as compression strength and freeze-thaw durability, as well as greater visual appeal at point of purchase.

Club store requirements are partly responsible for the emphasis on compression strength coupled with good looks. In that retail environment, cartons may be displayed on the same pallets used for shipping. Cartons must be strong enough to withstand the rigors of distribution, including stacking and scuffing, and also draw the eye of consumers.

To meet the dual need, Graphic Packaging International (GPI) combined its Z-Flute board--a non-fluted material-with its Composipac board. The former incorporates laminated interior strips of paperboard for extra strength, and the latter provides a shiny, scuff-resistant, reverse-printed film exterior for the cartons.

For visual appeal, the film-laminated exterior can be metallized, printed with metallic inks, embossed/debossed or windowed. The Z-Flute structure can be engineered with vertical reinforcing strips to strengthen corners, where two-thirds of compression strength is localized; with band strips around the carton's walls, for lateral support and corner strength; or in a custom configuration to meet the package's unique requirements.

The package eliminates the need for shipping cases. Club store personnel simply remove the shrink wrap from the pallet--which looks more like a display of products rather than a pallet load--and consumers help themselves to cartons.

The Z-Flute/Composipac cartons "are shiny and bright, with high-quality graphics. They look great in those warehouses, which can be dimly lit," says Mark Sinclair, director of research and development at GPI.

"The packaging gets the attention of the impulse buyer and also makes it more efficient for the club store to merchandise the product," he adds. Kraft Foods currently is launching multipacks of Nabisco Oreo cookies in club stores in cartons made of GPI's hybrid material.

Surviving freeze-thaw cycles

For products distributed to all types of retail stores, particularly in the grocery industry, protecting cartons from damage in distribution is a key concern. The profitability of food manufacturers and grocery stores is adversely affected when cartons are damaged, because torn, abraded and crushed cartons don't sell. At the same time, materials cost is always a concern for packagers.

Mrs. Smith's Bakeries was able to reduce both cost and damage to frozen-pie cartons when it switched from cartons made of solid bleached sulfate (SBS) board with a polyethylene (PE) coating to cartons made of MeadWestvaco Coated Board Group's Custom Kote Coated Natural Kraft (CNK) board. Cost reduction was the original goal, but the switch yielded another important benefit: improved compression strength.

Tests to gauge the performance of the 22-point CNK board cartons vs. 22-point PE-coated SBS cartons indicated that after five freeze-thaw cycles, the

CNK cartons were 20% stronger. The tests measured full box compression, stiffness and moisture content. CNK board is a high-gloss, two-ply, coated substrate made of a blend of pine and hardwood fibers. The natural brown backside of the board delivers the compression strength, and an engineered clay coating on the front side creates a smooth printing surface. Smurfit-Stone Container supplies the folding cartons to Mrs. Smith's.

Recycled board takes off

With an eye to reducing materials costs, a growing number of packagers are switching to recycled paperboard products. The current crop of coated, recycled boards offers lower cost (vs. virgin paperboard) without compromising the carton's structural integrity, high-speed machine-ability or printability.

"In the frozen food sector, we've seen a dramatic increase in recycled paperboard for these applications, and it has driven costs down," says Tony Petrelli, vice president-marketing and business development with Caraustar Industries Inc.

As an example, Pepperidge Farm Inc. switched from virgin paperboard to Caraustar's InverFreez recycled paperboard for its Pepperidge Farm Texas Toast, a frozen product.

Packagers of dry grocery products are making the switch, as well. Campbell Soup Co. chose Caraustar's Inverkote recycled paperboard to package its shelf-stable Campbell's Supper Bakes Meal Kits.

Blue Diamond Growers recently switched to recycled paperboard for its Nut*Thins Natural Nut & Rice Crackers carton. For Blue Diamond, the impetus was customer relations rather than cost.

Because Nut*Thins is sold in natural foods stores and aisles, its customers are more interested in environmental issues than the average consumer. In fact, customers had been suggesting recycled packaging for Nut*Thins; in response, Blue Diamond made the switch from virgin to recycled paperboard cartons.

"It's good for the environment, it's good for us and our customers were asking for it. We said, 'Let's give them what they want,'" says Jennifer Pfanner, marketing manager, Blue Diamond Growers Consumer Foods Div.