SPI resin identification coding system

Grab a plastic container around you, it could be a water bottle, a food container, peanut butter container etc. Look at the bottom of the container, can you find a triangular symbol with a number in it?

Well, it is called SPI resin identification coding system.

The SPI resin identification coding system is a set of symbols placed on plastics to identify the polymer type. The primary purpose of the codes is to allow efficient separation of different polymer types for recycling. Separation must be efficient because the plastics must be recycled separately. Even one item of the wrong type of resin can ruin a mix.

You should know the identity of the symbols to have a good insight about the qualities and uses of plastics that you'll probably use daily. It is important to use these plastics appropriately according to their capacities as misuse of them may cause them to release toxic that will often cause cancer. Not all type of plastics can be reused.

Table of resin codes

Source:

Recycling number				Symbol	Abbreviation	Polymer name	Uses	Recycling
1				♳	PETE or PET	Polyethylene terephthalate	Polyester fibers (Polar Fleece), thermoformed sheet, strapping, soft drink bottles, tote bags, furniture, carpet, paneling and (occasionally) new containers. (See also: Recycling of PET bottles)	Picked up through most curbside recycling programs.
2				♴	HDPE	High-density polyethylene	Bottles, grocery bags, milk jugs, recycling bins, agricultural pipe, base cups, car stops, playground equipment, and plastic lumber	Picked up through most curbside recycling programs, although some allow only those containers with necks.
3				♵	PVC or V	Polyvinyl chloride	Pipe, fencing, shower curtains, lawn chairs, non-food bottles and children's toys.	Rarely recycled; accepted by some plastic lumber makers.
4				♶	LDPE	Low-density polyethylene	Plastic bags, 6 pack rings, various containers, dispensing bottles, wash bottles, tubing, and various molded laboratory equipment	LDPE is not often recycled through curbside programs, but some communities will accept it. Plastic shopping bags can be returned to many stores for recycling.
5				♷	PP	Polypropylene	Auto parts, industrial fibers, food containers, and dishware	Number 5 plastics can be recycled through some curbside programs.
6				♸	PS	Polystyrene	Desk accessories, cafeteria trays, plastic utensils, toys, video cassettes and cases, clamshell containers, packaging peanuts, and insulation board and other expanded polystyrene products (e.g., Styrofoam)	Number 6 plastics can be recycled through some curbside programs.
7				♹	OTHER or O	Other plastics, such as acrylic, nylon, polycarbonate, and polylactic acid (a bioplastic), and multilayer combinations of different plastics	Bottles, plastic lumber applications, headlight lenses, and safety shields/glasses.	Number 7 plastics have traditionally not been recycled, though some curbside programs now take them.