Textiles — Quantitative chemical analysis — Part 22: Mixtures of viscose or certain types of cupro or modal or lyocell and flax fibres (method using formic acid and zinc chloride)

ISO 1833-22:2013 is applicable, after removal of non-fibrous matter, to binary mixtures of viscose or certain types of the current cupro or modal or lyocell fibres with flax fibres.

If a cupro or modal fibre is found to be present, a preliminary test should be carried out to see whether it is soluble in the reagent.

ISO 1833-22:2013 is not applicable to mixtures in which the flax fibre has suffered extensive chemical degradation, nor when the viscose, cupro, modal or lyocell fibre is rendered incompletely soluble by the presence of certain permanent finishes or reactive dyes that cannot be removed completely.