Not all plastics are created equal. Ever wondered why some plastics are classified a ‘3’, or what ‘PETE’ stands for? We’ve put together a handy guide to help you decipher the various plastic identification codes and become a better recycler.

A brief history of plastics codes

You could be mistaken for thinking that the little triangle made up of recurrent arrows with a number in the center on the bottom of your plastic bottle simple means ‘please recycle me’. The truth is, there’s much more to it than meets the eye. Gather a few different types of plastic products and you’ll start to notice slight differences in both the number and the abbreviation underneath the symbol itself.

All the way back in 1988, the US Society of the Plastics Industry introduced a code that would help manufacturers better identify the different types of plastics and what their recyclable status was. Though this was to be included on all consumer packaging, today most consumers remain unaware of just what these symbols actually mean, despite the adoption of similar plastic identification initiatives across the globe in the years that have followed.

Let’s break down the meaning behind these numbers and abbreviations.

Symbols of the Plastics Identification Code. Source: Chemistry Australia.

1: Polyethylene Terephthalate (PET)

PET is the most common type of plastic and can be found in a variety of products, including plastic bottles, clothing, textile fibres, pillow and sleeping bag filling. It is durable, transparent and known for its ability to hold different types of liquids without interacting with or compromising them. PET is rigid, though it begins to soften at around 55 degrees Celsius. If you’ve drunk from a plastic water bottle, you’ve come into contact with this type of plastic.

Can this be recycled? Yes, it is often recycled and reused for the purposes of making polyester fibres as well as other bottles. PET is commonly accepted by most recycling programs. Simply clean the item and sort it in the appropriate recycling bin for collection.

2: High-Density Polyethylene (HDPE)

The next most common type of plastic, HDPE is used to make both soft and hard products thanks to its ability to withstand higher temperatures. Unlike its transparent cousins, HDPE is normally white or coloured in appearance. Common applications include shopping bags, laundry liquid bottles, buckets and personal hygiene products like soaps and shampoos.

Can this be recycled? Yes, these products often return as piping, crates, outdoor furniture and pens. Studies have found that HDPE can be recycled up to 10 times.

3: Polyvinyl Chloride (PVC)

Third on the list is PVC, also known as “vinyl”. This category technically covers both plasticised and unplasticized PVC, known as PPVC and UPVC. This plastic is highly versatile, being used in both hard (UPVC) and soft (PPVC) products. It can be found in plumbing and construction applications, including conduit and piping, as well as electronics, toys, cling wrap and bubble wrap.

Can this be recycled? Yes, but it is difficult due to the presence of bisphenol A (BPA), of which the health effects have been the subject of ongoing scientific debate. When recycled, PVC can be reused to make detergent bottles, road cone bases and garden hoses.

The code helps manufactures and recyclers identify the different types of plastics. Source Nick Fewings/Unsplash.

4: Low-Density Polyethylene (LDPE)

A flexible plastic that is mainly used as a film for wrapping products. Common applications include garbage bags, squeeze bottles, food packaging, bottle rings and films that stretch and shrink. Due to its fragile nature, LDPE has a much lower heat distortion temperature, beginning to soften at 40°C.

Can this be recycled? Yes, however due to its fragile nature, it will likely need to be collected by a speciality recycling service. See the following for a list of compatible Australian and US recycling locations.

5: Polypropylene (PP)

Semi-crystalline, flexible and used in a wide range of applications, Polypropylene is a tough and rigid plastic that has good resistance to grease, moisture and chemicals. It is commonly used in home and garden products including compost bins, pots, medicine bottles, ketchup bottles, straws and kitchen containers.

Can this be recycled? Yes, although the status of this may vary depending on your region, due to a reduced demand for Polypropylene in recent years. If in doubt, check with your local service provider or council.

6: Polystyrene (PS)

Colloquially known as ‘Styrofoam’, Polystyrene is a lightweight, rigid yet brittle plastic that can be affected by solvents and fats. Category six also includes Expanded Polystyrene (EPS), identifiable by its energy absorbing and heat insulating properties. Both are commonly found in single-use applications, including packing peanuts, food trays, disposable cups and dinner wear. An inexpensive plastic that is favoured by manufacturers yet criticised by environmentalists due to its prevalence in landfills and how long it can take to decompose, with estimates ranging between 500 to 1 million years.

Can this be recycled? Polystyrene is difficult, but not impossible to recycle. Most consumer and council services will not accept Polystyrene if you put it in the recycling bin. You will need to locate a dedicated recycling center, or better yet, avoid using Polystyrene entirely.

7: Other

The catch-all category for other resin types, including acrylics, fiberglass, nylon and multi-laminate materials. Any other form of plastic that doesn’t fit nicely into the previous six categories will make an appearance here. Common applications include DVDs, baby bottles and sporting equipment to name just a few of the many varied products.

Can this be recycled? Category seven items are a mix of plastics, which can be the most difficult to recycle, and in some cases are not recyclable at all. These are commonly not accepted at consumer or council recycling centres, and you will need to check for a specialist recycling service or drop-off location in your local area.

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