These are macromolecules which consist of two or more different types of blended monomer units. In these polymers, monomer groups are statistically distributed or take the form of segments or blocks – segment copolymers or block copolymers. Thus the degree of crystallisation and the structure of the fibre can be altered. This means mostly that the melting point is lowered and often the rigidity as well and an increase in solubility. In the area of nonwovens the classic copolyester and the copolyamid is found. Through this fusible webs and adhesive stabilisers as well as coatings can be manufactured in order to produce combined textiles or combined with other materials such as metal, wood or plastic. A difference in temperatures is seen in both variants as well as in the viscosity. Copolyamids are processed at low temperatures. During recycling a high degree of sorting purity is necessary and, as many textiles consist of polyesters, copolyesters are often to be found here. Copolymers are thermoplastics. Using a suitable bonding with other materials they can also be manufactured with a thermal elasticity which further extends their property range.