Guide to understanding plastic recycling symbols and getting the most out of this material

Almost every piece of plastic packaging carries a small triangular symbol with a number inside it, somewhere between 1 and 7. Most consumers know it has something to do with recycling, but few know exactly what it means – and the confusion matters, because these resin identification codes were never designed as a simple "recyclable / not recyclable" instruction. They identify the type of polymer a product is made from, which is precisely the information that sorting plants need to route each item to the right recycling stream and turn it into new material.

Symbol for Plastic Recycling

The seven codes correspond to the main families of plastic resin used in packaging and consumer goods. 1 (PET) covers most drinks bottles and food trays; 2 (HDPE) is used for milk bottles, detergent containers and many rigid packaging items; 3 (PVC) appears in some pipes, films and packaging, though it is increasingly phased out; 4 (LDPE) is the resin behind most flexible films and bags; 5 (PP) is common in tubs, caps and many rigid containers; 6 (PS) covers polystyrene, including expanded foam packaging; and 7 (Other) is a catch-all for everything else, including multilayer materials, bioplastics and blends that do not fit neatly into the first six categories.

Crucially, these codes describe composition, not recyclability. A code 1 PET bottle and a code 1 PET clamshell tray can behave very differently in a sorting line depending on colour, additives, labels and contamination. And a code 7 item is not necessarily unrecyclable – it simply means the material does not fall into one of the six standard resin categories, so it needs to be evaluated on a case-by-case basis.

In practice, very few recycling facilities sort plastic by reading these printed codes one item at a time – doing so manually at industrial speed would be impossible. Instead, modern optical sorting systems use near-infrared and other spectroscopic sensors to identify the actual polymer composition of each item directly, often achieving far more precise and consistent results than a printed code ever could. This is especially important for items where the code is missing, illegible, or technically misleading due to multilayer construction.

That said, recycling symbols still play an important role upstream: they help packaging designers choose materials that are easier to sort and recycle, and they give consumers a starting point for understanding what their local recycling programme can accept. The real transformation, however, happens on the sorting line, where PICVISA's ECOPACK and ECOFLAKE optical sorters identify plastics by their actual material properties – resin type, colour and form – at speeds and accuracy levels that make large-scale plastics recycling economically viable.

Discover ECOPACK optical sorting