If their presence at the Society of Plastics Engineers' Annual Blow Molding Conference is any indication, materials manufacturers have aggressively set their sights on finding better ways to serve the blow molded packaging market, especially when it comes to meeting sustainability criteria.
It's no surprise that includes bio-based materials. Blow molding is becoming an increasingly important sector for these material suppliers, and the trick is balancing sustainability, processing and performance needs.
Braskem SA of São Paulo started its “I'm Green Polyethylene” production in Brazil in late 2010. The sugar cane-based PE can be recycled in the same stream already established for petrochemical PE, said Mark Mendelson, marketing portfolio director for Braskem America Inc. in Philadelphia. Officials look at the materials's cradle-to-cradle life.
The green PE now is routinely available to the North American market on a contract purchase basis. Consumers in certain markets are beginning to see it in packaging for everyday products — Pantene hair-care products in Brazil, Coca-Cola's Odawalla brand of juice beverages and Danone's probiotic Actimel drink released in France earlier this year. There is a website to communicate the benefits.
“Consumer education ... will be a brand-owner priority,” Mendelson said at ABC 2011, held Oct. 12-13 in Chicago. “It's the consumer that's going to make this choice.”
But manufacturers also have to convince consumers that responsible practices are used to harvest the sugar cane. Braskem is working to get across the message that its use of sugar cane does not impact the Amazon or the global food equation. Brazil owns 22 percent of the world's arable land; sugar cane grown for ethanol uses 1 percent of that, Mendelson said. The firm also has a code of conduct for its supply chain that includes human rights principles and proper agricultural practices for watering, fertilizing and harvesting.
“We're not burning down the Amazon forest,” he said. “Sugar cane production is mostly in São Paulo. The Brazilian government is giving us tremendous support.”
At Telles LLC in Lowell, Mass., — a joint venture of Metabolix Inc. and Archer Daniels Midland Co. that manufactures Mirel bioplastic resins — officials have developed new biomaterials for extrusion blow molding.
“There is a need for products that will allow consumers to participate in the green disposal movement,” said Robert Whitehouse, Telles senior customer application development manager.
“Plastics take 30 percent of landfills,” he said in an Oct. 12 presentation. “In Europe, there is no more land available for landfill. Managing waste is a global problem. One of the largest waste components is post-consumer.”
Recycling has been successful for PET bottles, still there is insufficient available feedstock. Recycling also has problems with removing trace contaminants — adversely affecting any life-cycle analysis and sending a confused message to consumers and other stakeholders, Whitehouse said.
Incineration gives off toxic gases. Industrial composting isn't working due to poor infrastructure management of waste collection, he said. Nonetheless, Mirel has its own challenges. The firm is trying to make the resin more suitable for extrusion blow molding and broaden its processing window. In part because of its high crystallinity, it is not suitable for injection blow molding.
The material can be formulated to have characteristics like those of polypropylene, or high or low density PE. It has similar oxygen, carbon dioxide and water barrier properties to PET, but Telles won't recommend it for soft drink bottles so as not to contaminate that recycling stream. Mirel also won't be targeted at HDPE milk containers for the same reasons.
Instead Telles will target consumer products like personal-care, detergent and small-container packaging applications.
Traditional resins are also facing the need to balance sustainability, processing and performance. Eastman Chemical Co. sees that as its goal in developing clear packaging resins, said Mark Treece, senior chemical engineer at the Kingsport, Tenn., firm.
“Balancing can be tricky, but certainly that's our objective.”
Eastman is working on its melt-phase copolyesters, including a new generation of coPET and one made for hot-fill applications.
Dow Chemical Co. of Midland, Mich., touted its Continuum EP HDPE for packaging. Market manager Stacy Fields said Dow's line will allow up to 10 percent of weight to be taken out without compromising performance.