Home compostable plastics If you see the home compostable sign it will most likely be the original bio-plastic, cellophane, which is made from cellulose derived from wood pulp. It is used for wrapping birthday cards, sweets and, more recently, as a base for bio-glitters. Cellophane will degrade within 28 to 60 days in a home composter at 20-30 degrees. Check for the home composting symbol to avoid contaminating your compost heap. To be clear – home composting isn’t the same as your council food caddy, which usually undergoes a different kind of composting process, but more on that later.
Oxy-degradable plastics These are sold as bags and straws and are actually petroleum-based plastics that break down into lots of little pieces. Yes, that’s right, they’re actually designed to turn into microplastics. The EU Environment Committee is demanding these are banned by 2020.
Compostable Plastics (commonly labelled as PLA) A polylactic acid derived from the sugar and starches of plants, most commonly corn starch and sugar cane. PLA is the clear bioplastic often used in salad and deli food boxes and as a liner in coffee cups and sandwich boxes. PLA will break down within 90 days in an industrial invessel composter running at 60 degrees. In order to be compostable it has to be tested and meets the criteria of EN13432
CPLA Like PLA but with added chalk. CPLA is used to hold food products that need to tolerate high heats: things like cutlery, coffee cup lids and for serving hot food. As with PLA, it needs to be broken down in an industrial invessel composter.
Biodegradable Plastics – This is a word used commonly used with bioplastics, but it can be misleading as most of us understand biodegradable to mean what happens to an apple core. In order for a bioplastic to be described as biodegradable it means it has passed the EN13432 test for industrial composting- so not like an apple core.
Water Soluable Bioplastics – Seaweed is being used to make drinking balls, and developed in Indonesia for washing liquids and food sachets which break down in water.
There are new materials being introduced all the time such as cassava root and thistle starch bags, but with all these materials its important to understand how long they take to degrade and what conditions they require. As most packaging in a food waste caddy will get pulled out for incineration before they have had a chance to break down, unless it is instant like the packaging puffs that you get. .