PET consists of polymerized units of the monomer ethylene terephthalate, with repeating C10H8O4 units. PET is commonly recycled, and has the number "1" as its recycling symbol. The majority of the world's PET production is for synthetic fibers (in excess of 60%) with bottle production accounting for around 30% of global demand. In discussing textile applications, PET is generally referred to as simply "polyester" while "PET" is used most often to refer to packaging applications (source : wikipedia).
Our Recycled PET (polyetylene terephtalate) bags are made of 80% and even 100% recycled PET-bottles. The advantage of the 100% recycled bags is that they are machine-washable at 30 % and the print or inkt is without dangerous chemicals. Moreover, these bags are again 100 % recycable at end of life and frespects the cradle to cradle theory.
(source : revolve-phil.com)