Resin identification code

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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

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, HDPE and PVC. 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.

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.

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.

Abbreviation	Polymer Name	Uses
PETE or PET	Polyethylene Terephthalate	Recycled to produce polyester fibres, thermoformed sheet, strapping, soft drink bottles. (See also: Recycling of PET Bottles)
HDPE	High-Density Polyethylene	Recycled to become various bottles, grocery bags, recycling bins, agricultural pipe, base cups, car stops, playground equipment, and plastic lumber.
PVC or V	Polyvinyl Chloride	Recycled to become pipe, fencing, and non-food bottles.
LDPE	Low-Density Polyethylene	Recycled to become plastic bags, various containers, dispensing bottles, wash bottles, tubing, and various molded laboratory equipment.
PP	Polypropylene	Recycled into auto parts and industrial fibers.
PS	Polystyrene	Recycled into a wide range of products including office accessories, cafeteria trays, toys, video cassettes and cases, insulation board and expanded polystyrene products (e.g. Styrofoam).
OTHER	Other plastics, including acrylic, polycarbonate, polylactic acid , nylon and fiberglass.