GB673711A - Process for the improvement of fastness properties of dyeings and printings producedfrom water-soluble dyestuffs - Google Patents

Abstract

The fastness properties of dyeing or prints with direct dyestuffs which are water-soluble owing to the presence of sulphonic acid or carboxyl groups are improved by treatment with an aqueous solution containing a condensation product of an aldehyde with a nitrogen compound containing at least once the grouping <FORM:0673711/IV (c)/1> which condensation product has been produced in the presence of acid in an amount of 0.1-0.9 equivalent for 1 mol. of nitrogen compound. Particularly suitable condensation products, which are advantageously employed in solutions of 0.05-0.4 per cent strength, are those of 1 mol. of dicyandiamide with 2-4 mols. of formaldehyde in the presence of 1/10 -\ba1/2 mol. of a lower fatty acid, preferably with 2-3 mols. of formaldehyde in the presence of 1/6 -\ba1/2 mol. of acetic acid. Formic acid or inorganic acids (e.g. sulphuric or hydrochloric acid) dicyandiamidine, guanidine, acetoguanidine, biguanide, alkyl- and aryl-biguanides, and di- or other poly-biguanides, and acetaldehyde, may also be used. The treatment, which may be carried out at room temperature or at elevated temperature, e.g. 70-75 DEG C., is applicable to dyeings and prints on animal fibres (e.g. wool or silk) or especially cellulosic fibres (e.g. cotton, linen, or artificial silk or staple fibre of regenerated cellulose), including after-coppered dyeings and prints with azo dyestuffs from o-hydroxy- or o-carboxy-diazo compounds and coupling components coupled in a position vicinal to a hydroxy group. Examples describe the treatment of dyeings on cotton with Brilliant Purpurine 10B, Chlorantine Red 8BN (Registered Trade Mark), or Direct Sky Blue green shade with various condensation products of dicyandiamide with formaldehyde in the presence of acetic acid and with a condensation product prepared similarly from a mixture of biguanide nitrate and guanidine nitrate obtained by heating dicyandiamide with ammonium nitrate, and the similar treatment of cotton dyed with Melantherine BH (Registered Trade Mark), the after-treated dyeing being subsequently discharge printed.