GB982913A - Process for dyeing and printing with reactive dyestuffs - Google Patents

Abstract

In the dyeing or printing of fibrous materials with reactive dyestuffs or reactive dyestuff intermediates the reaction between dye and the substrate is effected in the presence of a hydrazine containing at least one tertiary N atom, i.e. one of the two N atoms of the hydrazine must be bound to two C atoms, or a water-soluble salt thereof. The hydrazines may contain substituents that do not react with the reactive dyestuffs, e.g. halogen atoms, nitro, hydroxy or alkoxy groups but preferably contain only non-aromatic hydrocarbon substituents. The following hydrazines are specified: N : N-dimethylhydrazine, N : N : N1-triethylhydrazine and hydrazines and hydrazine salts of the formula <FORM:0982913/D1-D2/1> A combination of two or more hydrazines or their salts formed with sulphuric, hydrochloric, phosphoric, acetic, formic, propionic, chloracetic, oxalic or tartaric acid may be used. A large number of types of reactive dye are listed which may be from the oxazine, triphenyl-methane, xanthene, nitro, acridone, azo, anthraquinone and phthalocyamine series; they are preferably water-soluble. Vat dyestuffs of the water-soluble or insoluble type in their oxidised form as well as azo dyestuff intermediates containing reactine groups may also be used. The proportion of hydrazine compound used may vary from 1 mol of the hydrazine for each reactive group down to only catalytic proportions e.g. 0.2-2% by weight of the dyestuff. The hydrazine may be applied to the fibrous material before, after or together with the dyestuff or the dyestuff and the hydrazine may be reacted together and the resulting reaction product may then be applied. In other respects conditions conventionally employed in the application of reactive dyestuffs are used. To prevent unwanted reduction phenomena m-nitrobenzene-sulphonic acid may be used as an additive. Fixation may be achieved throughout a large range of temperatures and techniques including heating or steaming from 20-200 DEG C. dry heating at 250-300 DEG C. or exposing to the action of a high-frequency electric field. The following materials may be dyed or printed: paper, leather, silk, linen, cotton and regenerated cellulose. Many examples are given.