Science Fair Project Encyclopedia
Resin identification code
The code below is called the SPI resin identification coding system, developed by the American Society of the Plastics Industry in 1988.
Most plastics can be recycled, but because of the difficulty and expense of sorting, collecting, cleaning and reprocessing, at the moment it is only economically viable to recycle PETE, PVC and HDPE.
Thermoplastics can be remelted, but thermosetting plastics can only be crushed and used as insulation.
As you can not mix plastics together, they have to be separated into their different polymer types.
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. This symbol is otherwise known as the universal recycling symbol.
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 (1) and HDPE (2) are the only plastics collected in municipal recycling programs. Some regions, though, may be expanding the range of plastics collected as markets become available.
| Recycling No. | Abbreviation | Polymer Name | Uses |
|---|---|---|---|
| PETE or PET | Polyethylene Terephthalate | Recycled to produce soft drink bottles, deli and bakery trays, carpets, and fiberfill. (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 vinyl becomes pipe, fencing and non-food bottles. | |
| LDPE | Low-Density Polyethylene | Recycled to manufacture new grocery bags and films. | |
| PP | Polypropylene | Recycled into auto parts, cafeteria trays, carpets, geo-textiles and industrial fibers. | |
| PS | Polystyrene | Recycled into a wide range of products including office accessories, cafeteria trays, toys, video cassettes and cases, and insulation board. | |
|
| OTHER | Other plastics, including acrylic and nylon. |
External links
- http://www.plasticsindustry.org/outreach/recycling/2124.htm Society of the Plastics Industry site
- Recycle Symbol for Plastic Bottles | Plastic Recycling Symbols has symbols in many formats
- http://www.chemheritage.org/EducationalServices/FACES/poly/readings/rec.htm The Chemical Heritage Foundation
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