100 years of Indanthren dyes

s coined for the first synthetic vat dyes, which were discovered by BASF in 1901. Today, it stands for a full range of dyes with maximum fastness to light, washing and chlorine. Indanthren dyes are still the dyes of choice for the production of modern workwear and other special articles with high fastness. BASF Ludwigshafen, Germany, which discovered Indanthren, has recently transferred its textile dyes operations to DyStar.

The first official mention of Indanthren is a reference made on January 17, 1901 to a new blue dye discovered by René Bohn, a chemist working for BASF. The company submitted a patent application for this product on February 6, 1901. Manufacture of this dye opened up completely new dimensions for the dyeing and printing of cellulosics. Thanks to their outstanding properties, vat dyes rapidly became established on the market and Indanthren gained an almost unique reputation even with consumers. In the 1920s, people looking for quality and value for money were well aware of the advantages of clothing, curtains and towels that did not fade after repeated washing or exposure to sunlight. For decades, the Indanthren trademark was a sign of quality.

The triumphal progress of vat dyes was checked by two new trends: the rise of synthetic fibres and the development of reactive dyes for cotton. Even so, vat dyes have remained the products of choice for particularly high-quality dyed and printed cotton fabrics. In the wake of keen price competition in the textile sector, many textile finishers have been able to ward off cheaper competition by concentrating on high-quality specialities for which consumers are prepared to pay more. Vat dyes now have a stable market share of about 15 percent of the total market for textile dyes.
The integration of BASF?s textile dyes operations has made DyStar the market leader in vat dyes with a technological edge over its competitors. DyStar?s Ludwigshafen site is still the world?s largest integrated production facility for this class of dyes. The current Indanthren range comprises over 40 products for textile dyeing and an equally extensive assortment for textile printing. The modern dyes are simpler to apply than the early Indanthren products, processing costs are lower and they have a better environmental profile. All Indanthren vat dyes are metal-free. As pigment-type compounds they have virtually no bioavailability and thus very little impact on production effluent.

These days, DyStar?s development work on vat dyes focuses primarily on eliminating the need for reducing agents. A new electrochemical application process in which chemical reducing agents are replaced by electrons in an electric current opens up promising new prospects for the future. Following a year of laboratory tests, the first trials in customers' facilities are scheduled to take place in Indanthren?s centenary year. Project Manager Dr. Wolfgang Schrott expects this particularly environment-friendly dyeing process to give Indanthren new impetus and lead to a revival of interest in these dyes for sportswear and fashion garments.

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Contact:
Mister Karl-Heinz Michel