Polyester is a kind of polymer (molecule) that people use to make excellent, durable polyester labels. It can be natural or synthetic, biodegradable or not, and the most commonly used polyester is polyethylene terephthalate, better known as PET.
Some products are exposed to harsh conditions, severely cold or extremely hot temperatures, rough handling during distribution, cryogenic conditions or enclaving in laboratories, etc. These products need labels that will withstand all these conditions, and such labels usually cannot be made out of paper. Here steps in polyester with its fantastic characteristics: polyester labels are resistant to scuffing, tearing, abrasion, high heat, low temps, sunlight, chemical solvents, water, they have mechanical stability, controlled shrinkage, unmatched gloss or clarity (for a “no label look“) and can last a long time.
Many labels have a limited life-span, usually up to several months, after which they fade away, peel off, get torn, etc. Durable polyester labels can last many years, if the application demands it.
Of course, not ALL polyester labels have all these fantastic characteristics. Each polyester label is combined with other elements, such as an adhesive, printing style, lamination, etc, in order to make a suitable label for a specific application.
Polyester labels are most often used for:
Basically, polyester labels are an excellent choice for applications exposed to rough handling, outdoor conditions, water, repeated usage, etc.
Source: polyesterlabels.org
http://polyesterlabels.org/polyester-labels-university/polyester-labels-overview/