Azo group is a kind of organic compounds whose ends are connected with hydrocarbon groups (aliphatic hydrocarbon groups or aromatic hydrocarbon groups such as phenyl). Azo dyes have the most varieties among synthetic dyes. They are widely used in the dyeing and printing of a variety of natural and synthetic fibers, as well as in the coloring of paints, plastics, rubber and so on.
Azo (azo) in 1859, J.P. Grice discovered the first diazo compound and prepared the first azo dye aniline yellow. Azo dyes include acid, alkaline, direct, mordant, ice, disperse, reactive dyes, and organic pigments. According to the azo base contained in the molecule, it can be divided into monoazo, bisazo, triazo and polyazo dyes:
Monoazo dye Ar-N = n-ar '- Oh (NH2)
Bisazo dye ar1-n = n-ar2-n = n-ar3
Triazo dye ar1-n = n-ar2-n = n-ar3-n = n-ar4
Where AR is aryl. With the increase of azo number, the color of the dye deepens.
Azo test products
Clothing, bedding, towels, wigs, false eyebrows, hats, diapers and other cleaning and sanitary products, sleeping bags, shoes, gloves, watch belts, handbags, all kinds of wallets, briefcases and chair covers.
Textile or leather toys, toys with textile or leather clothing, synthetic dyes, organic compound dyes.
Fabrics and yarns used by consumers.
Azo is one of the necessary inspection items required by international environmental protection. There are two inspection methods: gas chromatography and mass spectrometry (GC-MSD) and high performance liquid chromatography (HPLC). The standard stipulates that the tested products shall not contain 24 kinds of azo dye intermediates. If one of them is detected, it is a unqualified product, and the limit requirements are as follows:
Decomposable carcinogenic aromatic amine dyes in GB 18401-2010: prohibited (limit value ≤ 20mg / kg);
GB 20400-2006 stipulates that decomposable harmful aromatic amine dyes: ≤ 30mg / kg (23 prohibited aromatic amines)
Reach (registration, evaluation, authorization and restriction of chemicals) Annex 17 entry 43 stipulates: prohibited (limit value ≤ 30mg / kg);
OEKO-TEX ® Standard 100 Appendix 4 stipulates: not used (limit value ≤ 20mg / kg)
Japan's Ministry of labor, health and welfare (MHLW) listed 24 azo dyes as hazardous pollutants and controlled them by amending the "act on the control of hazardous substances in household products". The law will come into force on April 1, 2016 (limit value ≤ 30mg / kg).
