Compostable Overwrap for Tea Bags

Listening to the stakeholders behind this determined effort is a vivid reminder of how many factors must be weighed before a compostable film can be commercialized.

It took nearly 10 years for Numi to develop its compostable overwrap for individual tea bags.
It took nearly 10 years for Numi to develop its compostable overwrap for individual tea bags.

It took about 10 years, and it wasn’t without a setback or two. But Oakland-based Numi Organic Tea now has an overwrap for individual tea bags that is ASTM D6868-substantiated as compostable in commercial composting facilities. Developed by sustainable packaging company Elk Packaging , the three-layer adhesive lamination consists of, from the outside in, paper/cellophane/polylactic acid. The cellophane layer is Futamura’s  Natureflex cellophane, a clear cast film made in Futamura’s plant in the UK of renewable wood pulp from managed plantations. According to Jake Hebert, Senior Manager of Sales and Marketing at Futamura, the gas barrier properties of this particular Natureflex are between 0.03 and 0.06 cc of O2/100 sq in./24 hr. “The crystalline nature of cellophane makes it a very effective oxygen barrier,” he adds. “In this particular application we include a very light metallization for moisture barrier. It’s such a minute amount it’s barely detectable when the material breaks down in the compost facility. Whatever does remain doesn’t hinder the degradation process because the aluminum is effectively inert, a naturally occurring element.”

The PLA, a blown extrusion that brings heat seal properties to the material, is PSI 's EarthFirst PLA. PSI sources PLA pellets from Total-Corbion, which in turn uses only GMO-free sugar cane to polymerize its Luminy brand PLA.

As for the paper, it’s FSI-certified virgin paper surface printed flexo and given a proprietary coating to protect the ink and deliver the right coefficient of friction (COF) required by the high-speed wrapping machinery.

When asked why it took 10 years to develop the desired structure, Numi Director Strategic Sourcing and Sustainability Jane Franch says it was mostly a matter of the industry not having the right materials, especially where flexible films are concerned.

“Ten years ago the market was just beginning to see some things in rigids, like compostable plates and cutlery for the to-go market that were starch- or potato-based materials,” says Franch. “But you weren’t seeing brands on store shelves in plant-based flexible films. And even PLA, which has been around for some time, was for a long time only made from genetically modified corn sources. As an organic tea company, that was never going to be acceptable to us. The PLA in our material is sourced from non-GMO sugar cane that is Bonsucro-certified, so it’s not only ethically sourced, it’s ethically grown.” Bonsucro Certification  is a program led by multiple stakeholders developed for the sugarcane industry to meet purchasing policies of large-scale buyers seeking suppliers who support fair labor and environmental protection in sugar producing communities.

“We knew from the beginning,” Franch continues, “that developing this packaging material was going to be challenging. But we figured we’d throw our hat in the ring and be committed at an early stage and to build a coalition of brands that were also committed so that we were able to demonstrate to those on the material supply side that there were in fact brands ready and willing to invest seriously in compostable flexible films. It required a commitment on our part to make the journey with the suppliers in terms of trialing early-stage materials. Keep in mind, too, that some of the compostable packaging materials that showed great promise over the years have now been phased out. But they did play a role, I suppose, in that they were precursors of the successful materials we have today.” In a nutshell, says Franch, that’s why it took 10 years to develop a compostable tea bag overwrap.

OSC2

The coalition of brands Franch mentions, which flies under the OSC2 banner, describes itself as a national community of CEOs and business leaders representing sustainably focused natural products companies. Its mission: “To address the toughest sustainability problems facing our industry and our planet by building new regenerative business models and agricultural systems.” Among the group’s core members are firms like organic nut butter maker Justin’s, baby food maker Plum Organics (part of Campbell’s Soup), organic baby food company Happy Family (part of Danone), grains producer Lundberg Family Farms, and California waste hauler Recology. Also enthusiastic participants, not surprisingly, are Elk Packaging and PSI.

“We’re like the chef behind the recipe,” says Elk Packaging’s Jeanne Cloutier, Director of Sustainability Projects. “We did the R&D and project management. It’s never a simple matter of is it compostable? It has to have the right coefficient of friction if it’s going to run efficiently on the specialized wrapping machine running at the copacker. Will it stand up in distribution? Can it be efficiently printed and laminated?”

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