Fiber reactive dyes - applications with low salt

A method for dyeing a substrate containing hydroxyl or carbamide groups comprising contacting said substrate with an aqueous solution of a dye of the formula:

• ##STR17## wherein:
• M represents a hydrogen atom, or an alkali or alkaline earth metal;
• n and m are 0 or 1;
• A is a benzene nucleus or a naphthalene nucleus;
• R is hydrogen or an alkyl group having 1 to 4 carbon atoms;
• R.sub.1 and R.sub.2 are hydrogen, hydroxyl, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, R.sub.1 and R.sub.2 are the same or different;
• R.sub.3 and R.sub.4 are hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, R.sub.3 and R.sub.4 are the same or different;
• X is a vinyl group, or a fiber reactive group of the general formula --CH.sub.2 CH.sub.2 --Z wherein Z is chloro, sulfato, thiosulfato or phosphato, sulfato;
• Y is selected from chlorine, bromine or fluorine, and the copper, cobalt, chrome and nickel metal complexes thereof.
• wherein:
• said dye is present in an amount from about 0.5 to about 6% by weight based on the weight of said substrate and wherein said aqueous solution contains an inert inorganic salt in about the following amounts relative to said dye concentration:
• ______________________________________ % Dye Salt g/l ______________________________________ 0-.5 10-15 .5-2 25-50 2-4 25-50 4-6 25-50. ______________________________________