Standard symbols for plastics

This procedure for establishing abbreviations, or symbols, is used to designate materials commonly known as "plastics" or "plastic materials", i.e. "any material containing, as an essential ingredient, a high polymer", as defined in ISO 472 (November 1999) and NF EN ISO 472 (January 2002) Plastics. Vocabulary.

The term "high polymer", or more generally "polymer", refers to "a product consisting of molecules characterized by a large number of repetitions of one or more species of atoms or groups of atoms (constitutional units), linked in sufficient quantity to give a set of properties which do not vary appreciably with the addition or elimination of a single or small number of constitutional units" (ISO 472). It is also a "product consisting of high molecular weight polymer molecules" (ISO 472).

In what follows, we'll concentrate on the way symbols are created and used for polymers, excluding those for elastomers.

Symbols characterizing polymers are widely used to designate them in an abbreviated way, both in language and in writing. They are often used in scientific and commercial documents, and even on the finished objects that make them up, in marking projects with a view to their recovery or recycling.