Plastic Numbers

andrewcheng | Plastic | 03/03/2011

What do the plastic numbers stand for?

I’m sure you’ve seen plastic products imprinted with a recycle symbol (the three circulating arrows) that has a number inside. While most people refer to these as “plastic numbers” or “plastic codes,” the official term is actually “Plastic Identification Codes” or PIC for short. There are a total of 7 plastic numbers which were introduced by the Society of the Plastics Industry, Inc (SPI) back in 1988. The numbers were intended for use in identifying plastic types during the recycling purposes. Yes, even back in the 80s, people had recycling in mind.

The following is a list of plastic codes and its associated plastic type:

• Type 1 is polyethylene terephthalate (PET or PETE)
• Type 2 is high-density polyethylene (HDPE)
• Type 3 is polyvinyl chloride (PVC)
• Type 4 is low-density polyethylene (LDPE)
• Type 5 is polypropylene (PP)
• Type 6 is polystyrene (PS)
• Type 7 is other (usually PC or ABS)

Why do plastics need to be identified for recycling?

In order to reuse recycled plastic for product manufacturing, it must first be separated by type. This is because some plastics simply cannot be melted together with each other due to differing melting points and properties. If different plastic types are melted together, the resulting mixture will solidify in layers (like oil and water) and very weak in structure.

The plastic numbers were intended to help consumers and plastic sorters differentiate plastic types. Ideally, to increase the value of sorted goods, recycled plastics should be separated by type and color.

Can you recycle all products marked with a plastic number?

Yes and no. While all plastics marked with a number can be recycled, not every facility can process them. In fact, most recycling centers will only take type 1 (PET such as water bottles) and type 2 (HDPE such as detergent bottles) plastics.

Note that while most grocery bags are made from type 2 HDPE plastic, most recycling facilities are not capable of processing them. The reason is that grocery bags tend to tangle up conveyor belts that clog up and slow the recycling streamlines. Before putting any plastic grocery bags in the recycling bin, make sure the facility can handle them. If you send a recycling center something they cannot process, it may end up in landfills (depending on the facilities’ regulations).

A sure shot place to send grocery bags for recycling is large-scale supermarkets such as Vons.

Below is a list of plastic numbers, its plastic type, properties, and common usages:

Plastic Number Type 1 – PET / PETE

Properties: clear, impact-resistant, flexible, colorless plastic with excellent barrier to alcohol, gas and moisture.

Common Uses: soft drink, juice, and other toiletry bottles.

Plastic Number Type 2 – HDPE

Properties: tough, excellent barrier to gas, moisture, oils, solvents, and chemicals.

Common Uses: grocery bags, juice & milk jugs, shampoo bottles, detergent & bleach bottles, water pipes, children’s toys, playgrounds, large barrels used to store chemicals & oil.

Plastic Number Type 3 – PVC

Properties: tough, biologically and chemically resistant

Common Uses: rigid piping, vinyl records, electrical insulation. Most PVC vinyl products contain phthalates, which mimic human hormones and also affect various life forms including fish and invertebrates adversely. For this reason, we do not recommend products made from PVC for food storage.

Plastic Number Type 4 – LDPE

Properties: flexibility, ease of sealing, barrier to moisture

Common Uses: grocery & garbage bags, cling wrap, frozen food bags, squeezable bottles, flexible container lids

Plastic Number Type 5 – PP

Properties: tough, resistant to heat, chemicals, grease and oil, versatile, and barrier to moisture

Common Uses: boxes, tupperware, microwaveable ware, disposable take-out containers, yogurt containers

Plastic Number Type 6 – PS

Properties: clear, easily formed

Common Uses: clear disposable cups, CD cases (the black and clear ones), packaging (Styrofoam)

Plastic Number Type 7 – Other (ABS, PC, etc…)