DYEING OF COTTON YARN WITH NAPTHOLS

JAGSON offers 17 napthols which in combination with bases can give a very large number of shades. The spectrum of shades available is particularly rich in yellow, orange, red, maroon, brown, blue and black. The dyeing possess very good fastness to light, soda boil and chlorine.

These napthols can also be produced on viscose and jute and by certain modifications in the dyeing recipe on silk, wool, nylon and polyester fibers.

Napthols are first applied to cotton in solution form. They form insoluble pigments on the fibre when coupled with diazo solution of amino compounds known as "fast bases" in dyestuff trade. napthols can be applied by several methods such as tub-dip, open beck, jigger, padding, circulating liquor ect. The dyeing of cotton, with napthols involves two separate operations :-

•  Impregnation of material with napthol solution.

•  Developing the impregnated material, with diazotised fast bases or Fast Salt solutions, Dyeing is followed by soaping aftertreatment, to develop true shade, to remove excess color pigment and to get normal fastness properties.

PROPERTIES

NAPTHOLS

•  napthols are available in micropulverised form.

•  These dyes are water insolubles which contain simple water soluble diluents.

•  The nature of solutions of napthols during application is highly alkaline having an approx. pH of 12-14.