Polyethylene terephthalate (PET, or sometimes PETE)
PET is a widely used plastic material that's lightweight, strong and often transparent. It's common in food packaging, including plastic water bottles, and also in fabrics, such as polyester. Sometimes a product will be labeled with rPET, which means the material used in the product is recycled PET.
High-density polyethylene (HDPE)
Polyethylene is the world's most common plastic, and it most often appears in three forms: high-density, low-density and linear low-density (we'll discuss those more below). The high-density version (HDPE) is the strongest of the three and is most often used in food packaging (most famously in gallon milk jugs). Many beverage cartons, including Boxed Water, are made with an HDPE liner to increase their effectiveness. HDPE is often selected for its strength and, particularly, its resistance to moisture, which makes it ideal both for storing milk and for more rigorous applications, such as pipes and plastic lumber, which can withstand years of weathering from rain and changing temperatures.
Low-density polyethylene (LDPE)
LDPE is a softer, clearer, more flexible version of HDPE—and it has its own strengths as well. It's often used as a liner inside juice and milk cartons, and it's used in corrosion-resistant work surfaces and other products, such as six-pack rings and plastic wrap. Lightweight plastic film, like a lot of LDPE applications, is lighter and more efficient than many alternatives, which helps us shrink our environmental footprint by reducing waste, energy use and carbon emissions.
Linear low-density polyethylene (LLDPE)
A tweak of the chemistry when processing LDPE yields linear LDPE, which is used in plastic bags—both the kinds you can get at the grocery checkout and the kinds that extend the shelf life of foods, such as lettuce and cauliflower, by weeks. LLDPE is tear and puncture resistant, and it also holds up well against chemical solvents, making it ideal for the purposes listed above as well as in pouches, toys, cable coverings and other higher-intensity applications.
Polyvinyl chloride (PVC/vinyl)
PVC is an incredibly durable material that's resistant to weathering, which is why it's so often used in building and construction applications. Common uses include flooring; siding; and indoor and outdoor plumbing, which uses PVC pipe. It's also resistant to chemicals and doesn't conduct electricity, making it crucial for use in high-tech applications, such as wire and cable. It's widely used in medical applications today because it's impermeable to germs, is easily cleaned and provides single-use applications that reduce infections in healthcare.
Polypropylene (PP)
PP is more heat resistant than some other plastics, making it ideal for use in food packaging and food storage that's made to hold hot items or be heated itself. It's another plastic that's chemically inert and durable, particularly when a product needs to be opened, closed or bent—like a hinge repeatedly (think of a DVD box). PP stretches to allow a consumer access to a product inside but retains its shape and strength for a long time.
Polystyrene (PS)
Polystyrene is among the most diverse plastic materials, able to be processed in a way that produces packing peanuts, home insulation and even red party cups. It's also one of the only materials that can be recycled or chemically processed to return back to its original state. All of these materials are recyclable, but often the process of recycling can cause some of them to lose important characteristics. In certain processes, used PS can be returned to its original state, losing none of the properties that made it so useful and diverse in the first place.
Polylactic acid (PLA)
More and more items, such as takeaway storage containers, cups and utensils, are being made with polylactic acid, a biodegradable bioplastic. Its biodegradability makes it ideal for sensitive medical applications, including implants, rods and screws. It's also one of the most popular plastics used in at-home 3D-printing applications. These types of plastic make a positive impact on our lives, day in and day out. While they're all unique, they can all be traced back to a single origin. Find out more about the history of plastics and how they came to be.