Cellulose is one of the very oldest feedstocks for plastics, dating back to the Nineteenth Century. Cellulose was the most important synthetic packaging material until the invention of oriented polypropylene (OPP) in the 1960s, which took away much of its business.
A custom compounder of cellulosics since 1932, Eastman Chemical of Kingsport, TN, produces Tenite acetate, butyrate, and propionate in a variety of formulations and plasticizer content ranging from 3 percent to 35 percent for molding and extrusion. Applications for Tenite butyrate include automotive and furniture trim, displays, and toys. Tenite propionate materials are used in appliance parts, cosmetic and personal care containers, and packaging.
Until very recently, neither consumers nor engineers seemed to really care that cellulosic plastics came from renewable resources-wood and cotton. It had good performance properties and it was inexpensive.
Now cellulose is hot again as a plastics feedstock. Innovia Films introduced NatureFlex, which meets biodegradability and compostability standards, but also provides a moisture barrier approaching that of co-extruded OPP. Innovia, a British company which operates a plant in Tecumseh, KS, says the new film has the best moisture barrier of any biopolymer available as a result of a unique coating technology. It’s intended as packaging for dried foods, such as biscuits, cereals, and snack bars. The new product can also be used as lamination to other biofilms.
A startup company in California has its eyes on cellulosic plastics based on cotton as a back sheet material for photovoltaic cells.
Eastman, the American giant, is also rethinking its strategy on the material. “Cellulosics present Eastman with a great sustainability story. It is one of the few bio-based polymers that exhibit good physical properties,” says Dan Bolton, market development manager. “Cellulosics allow us to be ahead of the game as the market moves to more sustainable materials. Bio-based materials are what consumers want and brands can get excited about telling this story.”
A team is in the early phases of determining the different ways cellulosics can be used in the current market. “We’re trying to determine if there are different chemistries we could use in a compounding process to improve the physical properties of cellulosics,” Bolton says. “We need to think outside our normal product portfolio,” he says.