It may be expensive and challenging to recycle, but multilayer packaging is established as the leading barrier technology for polyethylene terephthalate beverage bottles. However, based on comments from purchasing managers at two of the world’s largest soft-drink makers at a Maack Business Services PET conference in Zürich, bottlers would switch to other types of barrier packaging if lower-cost solutions were available.

Obviously, the purchasing managers — Barnaby Wallace of Coca-Cola Co., and Said Farha at rival Pepsi-Cola Co. — have an interest in driving down costs. Regardless, their comments reflect concerns the bottle blow molding industry should consider. “Affordability (of PET barrier packaging) is still a huge issue,” Wallace remarks. “It’s still very expensive.”

He notes that two markets of great interest to Coca-Cola — India and China — require low-cost packaging. Beverage prices in these markets are lower than elsewhere, so high package costs greatly cut into margins. According to Wallace, “In China, 70% of our sales are through wholesalers, so it could be up to three months before a consumer actually buys the beverage. This means our carbonated beverages require barrier packaging, so lower-cost barrier packaging is an area where we’d love to see greater development.”

Farha, meanwhile, notes the rising use of single-serve bottles, which, because of their higher ratio of volume to surface area than larger bottles, require higher barrier to limit oxygen ingress and carbon dioxide egress. “The key issue with small bottles is barrier (performance),” notes Farha.

Both Farha and Wallace cite recycling of multilayer bottles as another concern. Anne Roulin, director of PET package developer Plastics Technologies Inc. (Europe), Yverdon-les-Bains, Switzerland, explains that even though tielayers are not used in the multilayer barrier packaging now on the market, most recyclers still cannot economically separate the materials.

Roulin’s background includes development of plasma- and other coating technologies at Tetra Pak. She says that until these coatings prove cost-effective at high outputs, they will remain niche options. She reckons one firm that may turn the tide is blow molding machine maker Sidel, once it integrates the coating development team from Tetra Pak into its packaging development team. (Sidel was recently acquired by Tetra Pak’s parent firm, Tetra Laval.) “If they work together, they’ll come out with quite some developments,” she predicts. Other stretch blow molding machine manufacturers are working on coating systems (Dec 02 MP, 32; MPI, 35).

Another increasingly tapped alternative to multilayer packaging are oxygen scavengers, particularly Amosorb DFC from London-based BP. “There have been lots of [O2-scavenger specification] going on,” Roulin says, “especially for inline bottle blowing and filling,” since some of the oxygen scavenger’s performance is lost when filling takes place long after the bottles have been blown.

Amosorb, a transparent copolyester that bonds permanently with oxygen, is an active barrier, capturing oxygen as it permeates the bottle’s sidewalls and closure. Amosorb was first used as a layer in costly multilayer bottles, says Robert Rupprecht, BP’s market development manager, but its use in lower-cost single-layer packaging later emerged. Amosorb was commercialized in 1998 by Amoco Chemicals, which was acquired by BP the following year.