Polyester is a material produced from fibrous materials through polycondensation, and which can be modified in numerous ways. Thus, many tailor-made properties can be achieved. This material is thermoplastically melt-spinnable, can be processed in the middle temperature range and thermically weldable. The fibre cross section can be shaped from the cavity fibres through to the micro-fibres. Mechanical properties such as elasticity, rigidity, wet and dry durability as well as scrub resistance are classed between good and very good. Moisture absorption is very low and resistance to acids, solvents and the sun’s rays are also classed as between good and very good. Recycling is mostly done thermically.