GB433210A - Improved process of dyeing or printing cellulosic fibres - Google Patents

Abstract

Acid wool and basic dyes, dyeing with; printing; regenerated celluloses, dyeing.--In dyeing cellulosic fibres, e.g. cotton, artificial silk, linen, jute or ramie in the form of loose material, yarn, fabric or paper, with acid or basic dyes, the fibres are treated before or during the application of the dyestuffs with a carbamide-formaldehyde condensation product and with an organic base when acid dyes are used or with an organic p acid, other than tannin or tannic acid, when basic dyes are used, and the treated material is heated to harden the condensation product. Tartaric acid is specified as a suitable organic acid and specified organic bases are ethylenediamine, ethylamine, methylamine and hexamethylenetetraethylamine. The condensation products used are those of formaldehyde with urea or a derivative thereof, such as thiourea, dicyandiamide, biuret, guanidine, guanylurea or cyanuric acid and they may be used at any stage of condensation. The following examples are specified: (1) cotton fabric is impregnated by immersion for 5--10 minutes at room temperature in an aqueous solution containing dimethylolurea and sufficient acetic acid to give a pH value of 4,5 pressed until double its original weight, dried and printed with a paste containing British gum thickening and ethylenediamine, and the printed fabric is dried, heated by ironing with a hot iron for 2 minutes, dyed by treatment for \ba3/4\be hour in a solution containing formic acid and the dyestuff obtainable by methylating a technical mixture of the alkali salts of p-diaminoanthrarufin-2-sulphonic acid and p diamino - chrysazine sulphonic acid (cf. Specification 308,713, [Class 2 (iii)]), rinsed at about 50 DEG C. and dried, whereby the printed areas are coloured a deep blue, fast to light; (2) comparative prints on cotton fabric, illustrating the effect of the organic base on the quality of the colour, are obtained by printing with aqueous pastes containing (a) British gum and dimethylolurea; (b) British gum, dimethylolurea and ethylamine; (c) British gum, dimethylolurea and methylamine acetate; (d) British gum, dimethylolurea and hexamethylenetetramine, drying the prints, heating for 2 minutes at 165 DEG C., dyeing by treatment for \ba1/2\be hour in a solution at about 50 DEG C. containing formic acid and the dyestuff of (1), soaping for 10 minutes at 60 DEG C., rinsing and drying. The samples furnished under Sect. 2 (5) are of (A) cotton fabric treated with an aqueous solution containing dimethylolurea and (1) and (3) ethylenediamine, (2), (4) and (5) triethanolamine, (6) tartaric acid, (7) salicylic acid, heated for 1--4 minutes at 130--140 DEG C. and dyed with (1) Kiton blue A, (2) Orange II, (3) Kiton red G, (4) the acid dyestuff used in the above examples, (5) Benzyl green B, (6) Rhodamine B, (7) Solid green JJO, respectively; (B) cotton fabric treated with an aqueous solution containing a product obtained by heating heat-treated urea with 40 per cent formaldehyde and triethanolamine or tartaric acid, heated as in (A) and dyed with the acid dyestuff used in the above examples or Solid green JJO respectively and cotton fabric similarly treated with replacement of the heattreated urea by thiourea. The Specification as open to inspection under Sect. 91 comprises also reference to the use as organic acids of citric, oxalic and phthalic acids, and as organic bases of aromatic amines, e.g. aniline, and includes additional examples representing minor variations of the processes corresponding to the above samples. This subject-matter does not appear in the Specification as accepted.