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What are colorants?
Colorants are used by man since the prehistoric times and are characterized by their ability to absorb or emit light in the visible range (400-700nm). Colorants may be either inorganic or organic compounds. Both groups can be divided into natural and synthetic representatives. However, today, many natural colorants are produced synthetically. Colorants are either dyes or pigments. What is the difference between pigments and dyes?
How can we classify synthetic dye?Synthetic dyes can be named according to the chemical structure of the chromophoric group (azo dyes, anthraquinonic dyes, xanthene dyes, triphenylmethane dyes…) (Zollinger 2003). Colouristic approach characterizes dyes according to the dyeing method (in function of their mode of binding to the fibre) as reactive dyes, direct dyes, cationic dyes… The “Colour Index” (C.I.), published jointly by the Society of Dyers and Colourists (UK) and by the American Association of Textile Chemists and Colourists (USA), is the most extensive compendium of dyes and pigments for large scale coloration purposes, including 12000 products under 2000 C.I. generic names. It is useful to know that since an few decades the freely publication of new dyes and their classification have gradually diminished essentially due to reasons of intellectual property right and easy comparison of products. 
In the C.I. each compound is presented with two numbers referring to the colouristic and chemical classification. The “generic name” refers to the field of application and/or method of coloration, while the other number is the “constitution number”. You will find definitions of the different dye-types below ( http://www.fact-index.com ):
What is the situation of the colour industry?The traditional colour industry was an important activity in Europe until the end of 20 th century. It suffers now displacement to the developing world due to increasing production related environmental costs as well as high labour costs in Europe . New European White Paper on Strategy of Chemistry in EU will introduce a new system called REACH, for R egistration, E valuation, and A uthorization of Ch emicals that will enhance the constraints for the colour industry. The chemical synthesis pathways, as well as the dyeing of fibres are not fully worker friendly processes. Moreover, during dyeing processes approximately 10 % to 40 % of the dyes are not consumed on the substrate to which they are applied, and find their ways into wastewaters. They are flushed into the environment and constitute a certain risk to living organisms. At the moment, all dyes from recognized European manufacturers such as Dystar, Ciba, and so on are all friendliness to work. It is important to underline that no cases of cancer due to handle dyes in a dye-factory are known. Only some cases of bladder-cancer have been found with some dyes – now redrawn from their product lists since more than 30 years – at the manufacturing-stage of the dyes. For improved environmental performance through phasing out of toxic and hazardous substances and conversion in water, energy and raw material usage. This leads to a reduction in the quantities and pollution potential of various emissions. Several factors have resulted in the shift of dye usage from Europe to the Asian -Pacific area over the past decade. Dye manufacturing in Europe has been declining for several years due to competition from small and medium-size producers in these lower cost regions. The effect of the White Paper will be a further reduction of dyes available on the EU market as for many colorants the testing costs cannot be supported. 
A survey amongst dye companies has projected a situation in which about 2000 – 2500 existing colorants and about the same number of intermediates (mainly used for colorants) will be affected. This would result in testing costs of at least 1 billion Euros for the colorants industry. The future manufacture will not be economic in the EU, which will put the European textile finishing industry under additional constraints. It will be necessary to reformulate speciality products from a more limited choice of dyes; some effects may no longer be achievable. All changes of the last ten years affected the commercial performance of the major colorant companies. In the mid-1990 business was sluggish but it picked up in 1996 and 1997. Come the Asian crisis and we were back into a trough with lower returns in 1998 and 1999.An upswing in trade was first experienced in the fourth quarter of 1999 and 2000 saw profitability improving in most major companies. In the market share, work towards profitable growth, but not any price; avoid going for volume alone, it must be quality business with a good return and Joint ventures or strategic alliances in specific are very important in the market. Manufacturing eco friendly dyes enhanced export market opportunities. Manufacturers and retailers of textile goods will probably come under increasing pressure to comply with the international eco-labels. Given scenario of open world wide competition beyond 2005, securing of an eco-label will greatly assist manufacturers. Environmental biotechnology solutions account for less than 5% of the market. There is therefore scope for biotechnology to assist in this key environmental area. Biotechnology, as we have seen may be defined as the industrial exploitation of biological system or process. Biotechnology will develop new product and new market. How is the European dye market?Dyestuff enterprises in West Europe have transferred chemical manufacturing to Asia which subsequently promotes the development of dyestuff industry in Asia and impairs the proportion of West European dyestuff enterprises in the international dyestuff market. 
Structure adjustment of West European dyestuff manufacturers has all transferred dyestuff chemosynthesis to the developing countries in succession. Developing countries in Asia will inevitably become the dyestuff production and supplying bases in the world. In the recent years, dyestuff production in the West Europe is kept around 120000 tons, among which azo dyestuffs account 67%, anthraquinone dyestuffs account for 14%, deoxidizing dyestuffs account for 8% and others account for 11% (Sunfaith 2004). The total revenues for the European textile dyes and colours market were €739 million in 1997 and are forecast to rise at a rate of only 0,5% per annum through to 2004 raising the market size to € 0.8 billion. Sales volume is expected to rise from 80300 ton to 85900 tons. The main differences according to this survey is that reactive dyes, with total sales of 23.3 % in 1997 rising to 24.9% in 2004 will stay ahead of disperse dyes where the increase is from 19.7% to 20.3%. In United Kingdom the demand for dyes, including disperse, acid & mordant, basic and direct dyes has increased by a substantial 47% between 1998 and 2001, taking the market value to € 174,5 million in the latter year. However this is believe to have been partially offset by a 8% decline in 2002. The vegetable & animal colouring market has fluctuated somewhat over the review period, oscillating around € 31.8 million. The proportional importance has remained relatively static at approximately 2% (Market & Business 2003). |
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