Process for dyeing and printing

#The invention relates to a process for the dyeing and printing of organic materials with developing dyestuffs, whereby these are azo dyestuffs containing, as radical of the coupling component, a 6-membered heterocyclic radical having one ring nitrogen atom, as well as to the organic materials dyed and printed with these developing dyestuffs.

#Processes for dyeing and printing with substantive developing dyestuffs have been known for a long time. The first tests [DRP 14950 (1880), GB-PS 2757 (1880), 1638 (1881), 2946 (1882), 2580 (1885)] led to the so-called "ice colour technique", which temporarily played a part in calico printing. 2-Naphthol was used as the coupling component in this method. It was possible to influence the shade of colour by variation of the diazo component. It was not difficult in calico printing to dry the material impregnated with 2-naphthol sodium solution, to then print it with thickened diazo solution, and to wash out the 2-naphthol sodium remaining on the unprinted part. In dyeing, however, it was scarcely possible to dry yarns impregnated with 2-naphthol sodium solution so uniformly that the unfixed 2-naphthol did not migrate from the moister to the drier areas, and that by development with a diazo component an even dyeing could be obtained. The fastness properties of the obtained dyeings and printings were frequently inadequate, particularly with regard to fastness to rubbing, washing, chlorine and light. A disadvantage in application lay in the instability of the alkaline 2-naphthol solution and in the rapid atmospheric oxidation of the impregnated material. An appreciable advancement was brought about by the use of 2,3-oxynaphthoic acid arylamides [DRP 256.999, 261.594] as coupling components. These are appreciably more substantive than 2-naphthol; they are thus absorbed substantively from the alkaline solution onto the cotton fibres. Their solutions and the material impregnated therewith are more stable and the dyeings much faster. The products are insoluble and closely related with the metal-free azo pigments. They are very deeply coloured, extremely pure in shade of colour and have good fastness to light.

#By the choice of different amines, numerous arylamides of 2-hydroxy-3-naphthoic acid and a correspondingly high number of different shades of colour can be produced. The diazo components used are diazotised anilines, benzidines, aminodiphenyl ethers, aminodiphenylamines and aminoazobenzenes. The diazonium compounds can be stabilised as salts, e.g. as metal salts.

#A dye bath solution is prepared from 20 parts of the coupling component of the formula ##STR11## 20 parts of Turkey red oil, 6 parts of sodium hydroxide solution 36.degree. Be and 954 parts of hot water. Mercerised calico is impregnated with this solution on a three-roller foulard, squeezed out to 80 to 100% of the weight of the material and subsequently dried in a hot-air drying machine. The prepared and dried material is then printed on a screen printing machine, a roller printing machine or a rotary screen printing machine.

#For the preparation of the printing inks, a stock thickening of 600 parts of a thickening agent, 50 parts of urea, 10 parts of acetic acid (80%) and 340 parts of water is produced. The printing ink is obtained by the sprinkling of 15 to 70 parts (depending on the depth of colour desired) of a diazo compound into 985 to 930 parts of the stock thickening as this is being agitated with a high speed stirrer. The material after printing is dried and subsequently washed.

#After this operation there are obtained, with the diazo compounds of the aromatic amines (dye bases) given in column I of the following table, the shades listed in column II.