Certain consumer products need to be tested for chemicals to ensure safety as they could be harmful to human health and the environment.
Azo dyes are a popular coloration choice mainly because of their price, and good color fastness properties. Azo dye almost exists in all colors as one of the most widely-used synthetic dyestuffs in printing technique.
They are a large group of synthetic organic dyes that contain nitrogen. It is used for dyeing and printing of natural and synthetic fibers, and other products such as:
Disadvantages of Azo Dye
Azo dyes can be considered a risk to humans as they can contain nitrogen-nitrogen double bonds. The state of California (CA Prop 65) and the European Union have banned several aromatic amines which have been classified as carcinogenic. They reason is they can be liberated as their parent azo dyes undergo cleavage caused by a raised pH. Some acid dyes used to tone leather are synthesized using one or more of the banned amines and can be converted back to free amines by perspiration.
These types of dyes can not only be dangerous to human health but also the environment. The waste water from the factory after the product has been manufactured will bio-accumulate.
Because azo dyes are used in many consumer goods as colorants, they can cause harm by coming into contact with human skin. Some of these are considered as carcinogens which is why many markets across the world have banned them. This is why you need to be aware as an importer in order to comply with local regulations.
Azo Dye Preparation
Azo dyes tend to be produced in developing countries such as China India and Korea. They are used to dye many types of fibers – natural, artificial and synthetic – to color them. They are used because they make it easier to dye things such as cloth at lower temperatures and offer a wide range of colors. They are also longer lasting and won’t easily run in the wash meaning a better investment for both the manufacturer and consumer.
Azo dyes are the largest category of dyes, representing 60-70% of all dyes used for industrial purposes. Currently, there are more than 2,000 azo dyes in the market used to dye fibers, paints, varnishes, plastic, and rubber.
Their widespread use is due to the fact that they are economical and easy to use. Further, azo dyes also provide stronger and vibrant textile colors.
Azo Dye Test process
Azo Dye test is performed in order to confirm the presence of aromatic amines. Aromatic amines forms a disazonium salts when treated with HNO2. These diazo compounds couple with phenols like β-naphthols forms an orange azo dye which is insoluble in water.
Certain azo dyes can under reactive conditions cleave to produce primary aromatic amines which are known carcinogens and classified as skin sensitizers.
The AZO Dye test aims to protect workers, consumers and the environment from exposure to the carcinogenic aromatic amines, some of which are known to cause cancer and pose other serious health risks if exposed to the skin, ingested or released into the environment.
When textiles, garments and leather articles come into direct contact with the skin, some azo dyes will decompose into arylamines having carcinogenic properties (i.e. carcinogenic azodyes) when they blend with metabolite (perspiration) of human body. However, it presents great hazard if carcinogenic azo dyes are absorbed by human bodies. For the purpose of clarity, there are as many as 3,000 azo dyes in use and most of them are safe. Only about 200 azodyes are forbidden as they can be reduced to release arylamines having carcinogenic properties.
If you are an importer or manufacturer of leather or textile products, you need to ensure your products do not contain any one of 22 harmful AZO dyes. Other restricted hazardous substances in leather and textile products might include SVHC, DMF, PFOS, PoHS. As an importer, you might ask your suppliers to provide testing report regarding whether hazardous substances are present in your products or not.
