Flexible packaging looks for competitive edge

So, do you want the good news first, or the bad news? Good news: Flexible plastics packaging continues to grow substantially at the expense of metal and paperboard. Bad news: In the U.K., 40% of packaging processors report that despite improved volumes, profit margins are declining. So says the Packaging Federation (London).

This hard-fought market is actively seeking new packaging developments to reduce costs, allow better presentation on retailers'' shelves, and improve shelf life.

Nicholas Kokel, technical film manager at polyolefins producer Basell (Berre l''Etang, France), sees stand-up pouches, predicted to increase by 13.1%/yr in the next five years, taking major share from PVdC coated cardboard boxes, plastic detergent bottles, glass, and cans. The biggest change will be 16.1%/yr growth in large-sized pouches for moist pet food, he says. For such applications he proposes laminated barrier film in thicknesses of 100 to 150 µm, with layers of OPET, aluminum, nylon, and polypropylene (PP).

"This is a rather complex film construction with multiple lamination steps. PP fulfills sterilization requirements, [and] low gel PP resins are required to avoid puncturing the foil during lamination," Kokel explains.

Barrier is playing an increasingly important role in packaging, especially in light of growing demand for retortable containers, says Hiroyuki Oba, manager for packaging applications at processor Kureha Chemical (Tamari-mura, Japan).

The company''s new Besela laminating film is PET coated with a 1-µm layer of modified polyacrylic acid (PAA). Oba says Besela has gas barrier four times higher than comparable ethylene vinyl alcohol (EVOH)-containing multilayer films. Besela''s water vapor transmission rate is equal to both EVOH and nylon. Its high transparency makes it appealing to Japanese consumers who want to see the products inside pouches, he says. Next will be PAA-coated nylon and oriented PP films for lamination, and Kureha is working on a development (for introduction later this year) to provide high barrier in shrink film around bottles and containers.

Anton Wolfsberger, skills center manager for film at polyolefins producer Borealis (Kongens Lyngby, Denmark) also sees a boom for non-oriented PP films in sterilizable stand-up pouches. "The key criteria is as little embrittlement as possible after sterilization, especially at the sealing seam," Wolfsberger says. His company has come out with three Steripeel sterilizable, peelable seal grades. "Up to now sterilizable peel materials were limited in transparent applications," but with the introduction of grade WD160CF, the company has a clear solution, he says.

In the retortable coatings area to compete against low density polyethylene (LDPE), the company has developed a high-molecular-weight PP that has long chain branching to provide melt strength sufficient to allow take-off speeds of up to 500 m/min, about 100 m/min faster than PE-modified high-flow PP grades currently used.

Honeywell Specialty Films (Haventown, PA) has come up with high-barrier lamination film based on polychlorotrifluoroethylene (PCTFE), Aclar Ultrx 4000, to replace aluminum foil in pharmaceutical blister packaging. The film can be sterilized via autoclave or gamma ray, and offers moisture vapor protection said to be 10 times better than competitive polymer barrier solutions, according to David J. Gibboni, Honeywell''s marketing manager for pharmaceutical flexibles. The one drawback could be the film''s price, which reportedly is double the cost of aluminum foil and triple that of silicone oxide-coated films.

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