The 7 Types of Plastic: How to Identify Them and What They’re Used For
We all use plastic every single day—whether it’s a water bottle, food packaging, or the phone in your hand. But do you know that not all plastics are created equal? There are actually seven different types of plastic, each with its own unique properties, uses, and recycling processes. In this post, we’ll walk you through the different types, how to identify them, and what they’re most commonly used for.
1. PET or PETE (Polyethylene Terephthalate)
How to Identify It:
This one is easy to spot! PET is usually marked with a number 1 inside the recycling symbol. It’s often clear and shiny, like a water/soda bottle or a food container.
What It’s Used For:
PET is the most commonly recycled plastic, and it’s used for all kinds of things—especially single-use products. Think water bottles, soft drink bottles, and even clothing (yes, they can make fleece jackets and shoes out of recycled PET!). It’s lightweight, strong, and cheap to produce.
How to Recycle:
PET is commonly recycled into new bottles, containers, or even polyester fabric, but it’s best to rinse it out before tossing it in the recycling bin. If you have a PET bottle with a HDPE cap, LEAVE THE CAP ON. The cap is too small to be recycled by itself. PET is the easiest plastic to recycle using the Pullstruder.
2. HDPE (High-Density Polyethylene)
How to Identify It:
HDPE is usually marked with a 2 inside the recycling symbol. It’s typically thicker and stiffer than PET, and you’ll find it in things like milk jugs or detergent bottles.
What It’s Used For:
HDPE is strong and resistant to impact, which makes it perfect for products that need durability. It’s used for a wide range of products, including milk and juice containers, laundry detergent bottles, and even toys.
How to Recycle:
HDPE is another plastic that is easy to recycle, and it often gets turned into new bottles, plastic lumber, or piping. Be sure to rinse it out so it’s free of food residue before recycling. HDPE is my choice of plastic for injection mold machining, it is also good for extrusion with the Filastruder or even larger extruders.
3. PVC (Polyvinyl Chloride)
How to Identify It:
PVC is marked with a 3 inside the recycling symbol. It’s usually a rigid plastic but can also be flexible, like the material in plumbing pipes or floor tiles.
What It’s Used For:
PVC is super versatile. It’s used in everything from plumbing pipes, flooring, and window frames to clothing and upholstery. It’s also found in toys, credit cards, and even some medical devices.
How to Recycle:
PVC is a tricky one to recycle, and it’s not always accepted by curbside programs. When it is recycled, it can be turned into new products like tiles, flooring, or even new piping, but it can release harmful chemicals during the recycling process, so it’s not always the best choice environmentally. PVC does not get recycled very frequently compared to PET and HDPE.
4. LDPE (Low-Density Polyethylene)
How to Identify It:
LDPE is usually marked with a 4 inside the recycling symbol. This plastic is more flexible and less rigid than HDPE, so it’s commonly found in things like plastic bags and shrink wrap.
What It’s Used For:
It’s commonly used for things that need to be flexible, such as grocery bags, bread bags, and some kinds of wrap or film. It’s also used in some clothing, like activewear.
How to Recycle:
LDPE can sometimes be recycled, but it’s not always accepted in curbside programs. It’s typically turned back into new bags. If you’re looking to recycle LDPE, check if your local recycling center has a drop-off for plastic bags, otherwise it is not very likely to be recycled.
5. PP (Polypropylene)
How to Identify It:
Look for the number 5 inside the recycling symbol. Polypropylene is usually a bit more rigid than LDPE, and it’s often clear or opaque.
What It’s Used For:
PP is used in a variety of products, from yogurt containers and straws to plastic cutlery, bottle caps, and even automotive parts. It’s also resistant to heat, so it’s often used in microwave-safe containers.
How to Recycle:
Polypropylene is recyclable, but like many plastics, it’s not always accepted by curbside programs. Recycled PP can be turned into things like new containers, brooms, and even landscaping products. This plastic is another good option for extrusion machines.
6. PS (Polystyrene)
How to Identify It:
Polystyrene is marked with a 6 inside the recycling symbol. It’s most commonly seen in products like foam cups or packaging peanuts, though it can also come in rigid form, like in disposable cutlery.
What It’s Used For:
Polystyrene is often used in disposable products because it’s cheap to produce. It’s commonly found in things like disposable plates, cups, and takeout containers. The foam version is used for packing material because it’s lightweight and provides cushioning.
How to Recycle:
Polystyrene is notoriously difficult to recycle and is rarely accepted by curbside recycling programs. If it can be recycled, it’s usually turned into insulation or new plastic products. It’s better to avoid it when possible due to its environmental impact. There may be hope as researchers have found a “super worm” the darkling beetle which can survive on a 100% polystyrene diet.
7. Other (Various Plastics)
How to Identify It:
The “Other” category is a bit of a catch-all for plastics that don’t fall into the categories above. It’s marked with a 7 inside the recycling symbol, and you’ll often see it on multi-layer products like plastic containers that combine different types of plastics.
What It’s Used For:
This category includes a variety of plastics, including polycarbonate, acrylic, and bioplastics. It’s used for items like sunglasses, certain food containers, and even legos (although they are trying to make a switch to more sustainable materials). The properties of these plastics vary, so it’s harder to generalize their uses.
How to Recycle:
Recycling options for “Other” plastics depend on the specific type. Some are recyclable, while others are not. Polycarbonate, for example, can leach BPA, which is concerning for health and the environment, so it’s best to limit its use.
The Bottom Line
Knowing what type of plastic you’re dealing with is crucial—not only for recycling but also for understanding how best to dispose of it or reuse it. While some plastics are easier to recycle than others, reducing your plastic consumption and opting for more sustainable alternatives (like glass or metal) is always a good choice.
Next time you’re holding that plastic container, take a look at the number inside the recycling symbol. You’ll be one step closer to understanding what it’s made of and how you can help reduce its environmental impact!