PLA: Formulation, Attributes, and Applications

Poly lactic acid or PLA is a bio polymer created from annually renewable crops such as maize and sugar cane. The method of producing polylactic acid has been known for decades, but commercial interest in poly lactic acid has increased dramatically over the last few yrs due to the ability of the bio polymer to biodegrade in a commercial composting center.

Polylactic Acid Production
Maize is harvested from a farm and is separated into its various component parts. The corn sugar, dextrose, is then extracted. Dextrose is fermented, distilled, and transformed into lactic acid and lactic acid is then converted into poly lactic acid. The PLA is usually formed into pellets. The poly lactic acid pellets will then be purchased by manufacturers and employed in molds to form a variety of products and packaging, such as: food service ware (e.g., compostable cups), fabrics, furniture, medical devices, and more.

Polylactic Acid's Physical Attributes
Poly lactic acid plastic (often referred to as "corn plastic") has physical qualities that are quite similar to conventional petroleum based plastics like PETE or plastic #1.

Natureworks LLC and Manufacturers of PLA
Natureworks is a subsidiary of Cargill, and is the leading manufacturer of PLA in the USA. Natureworks makes PLA under the brand Ingeo, and has a manufacturing capacity of three-hundred million lbs / year. Polylactic acid is also fabricated by Purac Biomaterials and a range of other Chinese manufacturers.

Compostability
Poly lactic acid may be certified commercially compostable using the standards ASTM D-6400 and EN 13432 for compostable plastics. These standards validate that a product or product packaging made from poly lactic acid will 1) break down by sixty-to-ninety percent within 180 days of entering a municipal composting environment, 2) disintegrate by 90% into pieces no larger than two mm in size, and 3) will leave behind no heavy metals or other environmentally toxic substances in the compost beyond comparable levels in a control group of compost.

Food Ware Applications
PLA is used in a wide variety of biodegradable food packaging applications to help restaurants reduce food packaging waste. These include compostable: hot cups, forks, take-out containers, clear deli containers, and much more. Polylactic acid is one of the primary compostable materials in addition to sugar cane fiber, wheat straw, and paper. Polylactic acid is additionally applied as a biodegradable lining in compostable paper bowls and compostable paper hot cups. Using polylactic acid to line paper products allows the products to be certified as commercially compostable, but still keep liquid beverages, sauces, and other substances from leaking.