ISO 1833-20:2018

This document specifies a method using dimethylacetamide to determine the mass percentage of elastane, after removal of non-fibrous matter, in textiles made of mixtures of:
-  certain elastane fibres
with
-  cotton, viscose, cupro, modal, lyocell, polyamide, polyester or wool fibres.
This method is not applicable when acrylic fibres are present.
It is also possible to analyse mixtures containing certain elastane fibres by using the test methods described in ISO 1833-12 or ISO 1833-21.