Resin identification code, or Resin identification code, plastic material code, plastic material code and plastic code, is a classification code developed by the Society of the Plastics Industry in the United States in 1988. Most plastics are recyclable but need to be sorted according to their polymer type. Thermoplastics can be remelted, but thermosetting plastics can only be crushed as insulation.
The symbols of the plastic classification mark contain clockwise arrows, forming a complete triangle and enclosing the code. The abbreviation for plastic material is usually marked below the triangle. Plastic Numbers do not indicate how difficult or how often the material is recycled. It's just a random number that doesn't mean anything to a particular plastic material. In general, the bottom of plastic products will have the following labels, which define the scope of use. The containers marked with these Numbers are all qualified products, but can become toxic if not used properly.