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Your regular update for technical and industry information

ISO 17234-1:2020 Testing Standard of Azo Dyes in Leather is Now Published


In August 2020, the International Organisation for Standardisation (ISO) published the standard of ISO 17234-1:20201. It is a testing method for the determination of certain azo dyes which can release aromatic amines in dyed leathers. 

Azo dyes are a large class of very effective synthetic dyes used for colouring a variety of materials such as textiles, leather. A small proportion of azo dyes contains or can break down into aromatic amines. Some of the amines are carcinogens. These azo dyes are therefore restricted in textile and leather articles in certain countries, e.g. EU and China.

The updated standard is related to entry 43 of Annex XVII in REACH Regulation (EC) No. 1907/2006 which prohibits the use of azo colorants in textile and leather articles that may come into direct and prolonged contact with the human skin or oral cavity. Following the publication of ISO 17234-1:2020, the European Committee for Standardisation (CEN) will adopt this standard as new version of EN ISO 17234-12.

Please refer to below for the highlights of changes in the new version.

  • Newly add a clause for “Terms and definitions”;
  • Technical changes on apparatus and reagents;
  • Changes to sampling and preparation of samples, testing procedures to improve the test method;
  • Changes to interpretation of analytical in Annex C:

    • Provided the examples of false-positive results;
    • Suggested procedures;
    • Suggested comments in the test report;
  • Newly added an informative Annex D.

[1]  ISO 17234-1:2020

[2]  FprEN ISO 17234-1

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