Polyester is a type of polymer made from naturally occurring chemicals and plastics. It is extensively used in clothing and underwear. Blended with cotton, it can be strong, wrinkle resistant and reduce shrinking. Therefore, good for underwear. Whereas synthetic fiber blends have a high water resistance. Therefore, good for swimwear.
Polyester has many benefits:
It resists stains well
Strong but lightweight
Quick drying – so it is great for swimwear
It’s easy to look after – so you can wash it time and time again
It can easily be dyed, therefore underwear with digital prints is usually made with polyester
However, it is not as breathable as fabrics such as cotton. This can be a disadvantage in underwear. Ideally, you want the underwear to breathe and wick away moisture. Some people with sensitive skin can have allergies to polyester clothing.