Biodegradability: is printed PLA eco-friendly

What it means

In biodegradation, microorganisms break the material down. Temperature, moisture and the environment decide it, not just what the plastic is made from. That is why biodegradable, compostable and made from renewable sources are not the same thing. A bioplastic can be made from plants and still not break down in nature, and conversely, some oil-based plastics can be broken down.

PLA in practice

PLA is made from corn or sugar cane and is polylactic acid. It breaks down at around 58 °C and above in damp conditions, that is, in an industrial composter. In a garden, in a forest or in a landfill it breaks down very slowly, on a scale of years.

For a printed part that is actually good news. A holder or small box made of PLA will not start to rot in your flat or car, because that takes heat and moisture of a kind not normally found there. Note, though, that in a hot car PLA can deform before it would break down.

PETG and the others

PETG is derived from PET and does not biodegrade. In principle it can be recycled, but it has to be collected. If biodegradability matters to you, PLA is the only one of our two options that goes in that direction. Still, the choice should always suit the purpose, and brittle or dimensionally unstable PLA makes no sense where you need heat resistance or toughness.

What to do with a printed part after use

Put it in ordinary household waste, not in garden compost and not in the plastic bottle collection. If you collect biowaste industrially, check with the operator whether it takes PLA. The best ecology, though, is a durable part that does not need replacing.

The truth about labels on the spool

On PLA packaging you will often find words like bio, eco or compostable. A label without a standard means little. For industrial composting there is the European standard EN 13432, and the certificate has to apply to the specific product, not to the raw material. A filament with dyes and additives need not meet it, even if PLA is the base.

For you as a customer, one thing matters: biodegradability does not show itself in use. Your PLA box will last until you destroy it with heat, sun or a knock. You decide on its breakdown only when you dispose of it.