Compostable bioplastics made from plant starches
What is PLA?
PLA is a compostable bioplastic derived from plant sugars. PLA stands for polylactic acid. It can be made from any sugar, such as corn starch, cassava, sugar cane, or sugar beet. NatureWorks is the world’s largest producer of PLA, and a key partner to Vegware. Industrial corn is the primary source crop at the moment, but NatureWorks are working actively to diversify feedstocks, investigating other fibrous non-food crops, or even creating lactic acid from carbon dioxide or methane.
NatureWorks refer to their PLA under the Ingeo brand, and offer full information online on how it is made, and end of life options.
How PLA is made
Corn plants are milled to extract the starch, in the form of glucose. The glucose is then fermented to produce lactic acid. Next up, a chemical process transforms the lactic acid into a polymer, which can be made into pellets, known in the industry as resin.
Just like a conventional plastic resin, the PLA pellets can be used in a variety of ways – extruded into a sheet or film, injection moulded, cast into sheets, or spun into fibres. PLA has a huge range of applications, but at Vegware we use it for:
PLA-coated board for paper cups and soup containers
Clear cold cups, salad containers, deli and portion pots, and lids for a variety of products
Clear windows in sandwich wedges, salad boxes and bags
PLA – not a threat to plastics recycling
Compared to conventional plastics, bioplastics currently represent a tiny fraction of packaging, so it is not currently economical to sort PLA from other waste streams. If there is a major increase in bioplastics volumes, then waste sorting facilities can be calibrated to recognise and sort bioplastics using near-infrared identification. As well as composting, PLA is suitable for mechanical recycling into new PLA, as practised by Looplife Polymers in Belgium.
Studies have shown that low levels of bioplastics do not harm plastics recycling. German and Italian researchers have found there was no reduction to quality, up to these levels:
Up to 3% PLA in post-consumer PP plastic recyclate (1)
Up to 10% PLA in PS plastic re-granulates (1)
Up to 1-2% PLA in recycled PET plastic short-spinning plant (2)
Up to 10% MaterBi in the recycling of PE plastic shopping bags (2)
A compostable lunch: PLA cold cups and portion pots, PLA linings in our hot cups, and CPLA coffee lids and cutlery