<p>PURPOSE: An elastic fibre is provided to have a high elongation in case of break and to have a high elastic resilient degree. CONSTITUTION: Elastic fibre of a mixture containing a copolyester ether or a copolyester ester and a chemically cross-linked rubber, which fibre has a permanent elongation after 100 % stretching of at most 9 % and an elongation at break of at least 450 % and a process for producing an elastic fibre comprising the melt spinning of a mixture of a copolyether ester or a copolyester ester and a rubber to form a fibre, in which the rubber is completely or almost completely cross-linked at the moment the fibre is formed.</p>
