Process for dyeing animal textile fibers comprising the use of purified synthetic food dyes

A textile dyeing process for dyeing a textile material, product or article of fibers and fabrics consisting of animal hair, comprising the following steps, wherein steps 1) to 5) take place under stirring:

• 1) dipping the textile material, product or article for a period between 5 and 15 minutes into a water-based dyeing bath having a temperature between 20 and 30° C., said bath comprising at least:
• 2,2-dimethyl-1,3-propanediol (CAS no. 126-30-7) as a detergent substance;
• a wetting substance selected from polyethylene glycol-10 propyl ether ((C2H4O)nC10H22O, CAS no. 160875-66-1), petroleum distillate (CAS No. 64742-47-8), undecyl alcohol ethoxylates (CAS No. 127036-24-2) and a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (CAS no. 55965-84-9);
• a leveling substance selected from 5-sulfosalicylic acid (CAS no. 97-05-2), polyethoxylated tallow amines (CAS no. 61791-26-2), quaternary salts of polyethoxylated tallow amines with diethylsulphate (CAS no. 68071-95-4) and a mixture of C16-C18 ethoxylated unsaturated alcohols (CAS no. 68920-66-1);
• an acidity regulator consisting of a mixture of citric acid (CAS no. 77-92-2) and 5-sulfosalicylic acid (CAS no. 97-05-2), in a weight ratio between citric acid and 5-sulfosalicylic acid between 4:1 and 9:1;
• 2) adding to the dyeing bath of step 1 one or more synthetic coloring substances, bringing the bath to a temperature between 80 and 120° C. in a time between 50 and 80 minutes, leaving it at this temperature for a time between 30 and 90 minutes, and finally cooling the bath to a temperature between 60 and 80° C. in a time between 10 and 30 minutes;
• 3) draining the bath and subjecting the textile material, product or article dyed in the previous passages to a first wash in the same machine at a temperature between 35 and 55° C. for a time between 5 and 15 minutes;
• 4) draining the bath of the first wash and subjecting the textile material, product or article to a second wash in the same machine at a temperature between 20 and 35° C. for a time between 2 and 10 minutes in water, or at 50° C. for a time between 2 and 10 minutes in a solution of sodium acetate in water;
• 5) draining the bath of the second wash and subjecting the textile material, product or article to a color fixing treatment in a bath containing a fixing substance with a percentage between 1% and 6% with respect to the initial weight of the textile material, product or article at a temperature between 20 and 60° C., for a time between 5 and 30 minutes, and at a pH between 4.5 and 6.5 obtained with a pH regulator consisting of a mixture of citric acid and 5-sulfosalicylic acid in a weight ratio between 4:1 and 9:1, and said fixing substance is selected among diethylene glycol, a 5% suspension of silica in water, or a mixture thereof;
• 6) draining the bath and subjecting the textile material, product or article to drying.