Biofilm, compostable film, film made from renewable materials

The above heading is used to find and market what are known as biofilms.

"Biofilm" has become the umbrella term for films which have environmentally friendly properties and/or are manufactured from renewable materials.

We do however need to consider the definition of film properties in more depth and make distinctions between them. A compostable film does not necessarily have to be made from renewable materials. And likewise a biofilm does not necessarily have to be compostable. There are two main features to consider for biofilms:

• Compostability - a film can be described as compostable if it satisfies DIN 13432. Then it can be labelled with the "seedling" symbol.
• Renewable materials forming the main component of the film (source of raw material and/or polymer designation).

There are basically 3 bio-based types of plastic on the market:

• Those based on starch
• Polylactic acid (PLA, polyester)
• Cellulose

Polyhydroxy fatty acid may represent a further type in the future.

Some biofilms may display two or three of the properties and some just one. Just as when manufacturing plastic from an oil base, the renewable materials are processed in blends with the addition of synthetic additives. This has to be done to ensure production, processing and certain properties.

It should come as no surprise that compostable films are advertised as "bio" even if they are made from oil-based materials...