International code points to recyclability and uses

Plastics have proliferated on the planet over the past century. They’ve now become an enormous environmental problem, because they can take forever to degrade and are a common pollutant. In addition, many of them are manufactured using fossil fuels (though they don’t have to be), which contributes to global warming.

Plastics can, however, be recycled. But different types of plastics are recycled in different ways. So, the Society of Plastics Industry set up a series of codes, 1-7, called the resin identification code that you see on the bottom or side of any commercially made plastic. Here are common characteristics of the most ubiquitous plastics:

Number 1: PET (poly)ethylene terephthalate. This plastic is transparent and high strength, and sinks in water. It provides an effective barrier to gas and moisture, and resists heat. You’ll find PET in plastic soft drink and water bottles, mouthwash bottles, peanut butter and salad dressing containers, and oven-tolerant pre-prepared food trays. It’s commonly recycled.

Number 2: HDPE (high density polyethylene). This material has a translucent to opaque matte finish, and floats in water. It’s probably made of the toughest polymer material out there; it’s chemical and moisture resistance. HDPE is found in milk, water and juice containers, trash and retail bags, liquid detergent bottles, yogurt and margarine tubs, and cereal box liners. It, too, is commonly recycled.

Number 3: PVC (polyvinyl chloride). This plastic is transparent, translucent or opaque. It sinks in water, and is very hardy. It’s resistant to chemicals, grease and oil. It’s found in clear food packaging, shampoo bottles, medical tubing, and wire and cable insulation. And here’s its problem: it’s not recycled.

Number 4: LDPE (low density polyethylene). LDPE can be nearly transparent or opaque and low to high gloss. It floats, is tough and lightweight, and provides a barrier to moisture. It’s found in bread bags, frozen food bags, squeezable bottles, fiber, tote bags, bottles, clothing, furniture, and carpet. It’s also not commonly recycled.

Number 5: PP (polypropylene). It’s transparent, translucent, or opaque. It floats. It’s resistant to chemicals, heat, moisture, grease and oil. It’s found in ketchup bottles, yogurt containers, margarine tubs, medicine bottles, drinking straws, packaging materials, and loudspeakers. It’s also not usually recycled (but that’s beginning to change).

Code number 6 means any combination of plastics, and code 7 includes any other plastics not mentioned here (the industry’s changing very quickly).

Sources: Wikipedia, Society of Plastics Industry, California Coastal Commission

type of waste that can be recycled, how to identify plastic type