Recycling by product massive number of types of plastic, they each carry a resin identification code, and must be sorted before they can be recycled. This can be costly; while metals can be sorted using electromagnets, no such 'easy sorting' capability exists for plastics. In addition to this, while labels do not need to be removed from bottles for recycling, lids are often made from a different kind of non-recyclable plastic. To help in identifying the materials in various plastic items, resin identification code numbers 1-6 have been assigned to six common kinds of recyclable plastic resins, with the number 7 indicating any
Styrene-acrylonitrile resin Uses include food containers, water bottles, kitchenware, computer products, packaging material, battery cases and plastic optical fibers. The acrylonitrile from SAN containers has been found to migrate to content in variable amounts. Acrylonitrile is classified as a Class 2B carcinogen (possibly carcinogenic) by the International Agency for Research on Cancer (IARC). Acrylonitrile has been shown to increase rates of cancer appearance in high dosage tests in male and female rats and mice. Styrene-acrylonitrile resin Styrene acrylonitrile resin is a copolymer plastic consisting of styrene and acrylonitrile. It is also known as SAN. It is widely used in place of polystyrene