The
English chemist William Perkins accidentally discovered the synthetic dye,
mauve, in 1856, while he was trying to synthesize quinine in aniline. Before
that time, all coloring materials were extracted from barks, roots, seeds,
leaves and shellfish. Most synthetic dyestuffs are made from coal-tar
derivatives. Their manufacture is a highly complicated technical operation,
which is constantly changing. There is variation in the manner in which
different fibers respond to dyestuffs and even the same fibers do not produce a
full range of colors with a particular type of dye.
Basic or Cationic Dyes
This
group was the first of the synthetic dyes to be taken out of coal-tar
derivatives. As textile dyes, they have been largely replaced by later
developments. However, they are still used in discharge printing, and for
preparing leather, paper, wood, and straw. More recently they have been
successfully used with some readymade fibers, especially the acrylics. The name
means that these are dyes with an organic material, which is soluble in a
simple acid. Basic dyes were originally used to color wool, silk, linen, hemp,
etc., without the use of a mordant, or using agent. With a mordant like tannic
acid they were used on cotton and rayon. Basic dyes give brilliant colors with
exceptional fastness to acrylic fibers. They can be used on basic dyeable
variants of nylon and polyester.
