Resin identification code

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Sorted household plastic waiting to be hauled away for reprocessing.
Sorted household plastic waiting to be hauled away for reprocessing.
Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap
Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap

The symbols in the table below belong to the SPI resin identification coding system, developed by the NA Society of the Plastics Industry in 1988.

Most plastics can be recycled, but they have to be separated into their different polymer types. Because of the difficulty and expense of sorting, collecting, cleaning and reprocessing, at the moment it is only economically viable to recycle PETE and HDPE. (PVC is claimed to be recyclable, but it is in fact not a single material due to the wide variety of toxic additives for various applications; PVC is fundamentally toxic waste[citation needed]). Thermoplastics can be remelted, but thermosetting plastics can only be crushed and used as insulation.

The symbols used in the code consist of arrows that cycle clockwise to form a rounded triangle and enclosing a number, often with an acronym representing the plastic below the triangle. When the number is omitted, the symbol is known as the universal Recycling Symbol, indicating generic recyclable materials. In this case, other text and labels are used to indicate the material(s) used.

Contrary to misconceptions, the number does not indicate how hard the item is to recycle, nor how often the plastic was recycled. It's an arbitrary number and has no other meaning aside from identifying the specific plastic. The Unicode character encoding standard includes the resin identification codes, between code points U+2673 and U+2679 inclusive. The generic material recycling symbol is encoded as code point U+267A. Already recycled resins are coded with R- letter prefixed to them. Such as a PETE bottle which is made of already recycled resin could be marked as RPETE using same numbering.

[edit] Availability of recycling facilities

Use of the recycling symbol in the coding of plastics has led to ongoing consumer confusion about which plastics are readily recyclable. In most communities throughout the United States, PETE and HDPE are the only plastics collected in municipal recycling programs. Some regions, though, are expanding the range of plastics collected as markets become available.

Recycling No. Abbreviation Polymer Name Uses once recycled
♳ PETE or PET Polyethylene terephthalate Polyester fibres, thermoformed sheet, strapping, soft drink bottles.

(See also: Recycling of PET Bottles)
♴ HDPE High density polyethylene Bottles, grocery bags, recycling bins, agricultural pipe, base cups, car stops, playground equipment, and plastic lumber.
♵ PVC or V Polyvinyl chloride Pipe, fencing, and non-food bottles.
♶ LDPE Low density polyethylene Plastic bags, various containers, dispensing bottles, wash bottles, tubing, and various molded laboratory equipment.
♷ PP Polypropylene Auto parts, industrial fibers, food containers.
♸ PS Polystyrene Desk accessories, cafeteria trays, toys, video cassettes and cases, insulation board and expanded polystyrene products (e.g. Styrofoam).
♹ OTHER Other plastics, including acrylonitrile butadiene styrene acrylic, polycarbonate, polylactic acid, nylon and fiberglass.  

Legislation is currently being considered would add a "0" code for compostable polylactic acid.[1]

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