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Azo Dyes in Leather

‘Hide’ (or Animal Skin) needs to be tanned and treated with certain chemicals before it achieves the characteristic ‘leather look’. Chemicals are also needed to preserve the hide before tanning, or while the hide is in transportation.

Azo compounds are compounds containing the nitrogen or azo group (a bivalent group –N=N- united by two aromatic groups). Due to the brilliant colours of aryl azo compounds, they often find use in dying and pigmentation, and are thus commonly known as Azo Dyes. Around 70% of dyes used for colouring leather are azo dyes. You can read more about the chemistry of azo dyes here.

Colored Leather SheetsWhile most azo dyes are suitable for use, there are some that contain aromatic amines which release carcinogens (cancer causing substances). Exposure to them is harmful to human health. In many developed countries of the world, particularly European countries, use of certain azo dyes has thus been restricted. This has been done to protect consumers from substances hazardous to human health.

If you are an exporter of textile or leather products to EU countries, you have to ensure that your product does not carry any of the banned azo dyes. Also, every individual part of your product must comply with the limits. For example, shoe laces in footwear need to comply with the limit of 30ppm, as well as leather parts of the footwear.

Responsible manufacturers across the world can protect their workers and consumers by avoiding use of the 22 harmful aromatic amines as recognised by the EU. Azo dyes which do not release these aromatic amines should be used.

Click here to read the EU legislation and learn which azo dyes are harmful.

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Posted by on May 23, 2012 in Leather, Tanning & Chemicals

 

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