Patent GB-309166-A (GB)
Title: A process for dyeing and figuring woven, knitted and plaited fabrics, leather and other fibrous materials
IPC: D06P1/12
Filed: 1929-03-08
Abstract: 309,166. Haendel, W. April 7, 1928, [Convention date]. Diazotype processes.-The Specification as open to inspection under Sect. 91 (3) (a) comprises a process for figuring woven, knitted and plaited fabrics, leather, and other materials by treating the materials with light-sensitive bodies and sub. sequently exposing them to the action of light under negatives. The light-sensitive bodies used may be such as form dyestuffs under the action of light, such as mixtures of a. sulphonated diazocompound, e.g. sodium phenyldiazosulphonate, and an azo component, e.g. aniline hydrochloride or sodium phenolate, or light-sensitive bodies may be used which lose the capacity to form dyestuffs under the action of light. Suitable bodies of this kind are, diazo-compounds, other than diazosulphonates, and nitrophenyl lactic ketone. which forms indigo when developed with alkali, but loses this capacity when exposed to light. When employing bodies which form dyestuffs under the action of light, the process may be carried out by exposing the material under photographic negatives; and by using negatives representing different colours, the negatives having been taken behind light filters, coloured objects may be reproduced in their natural colours. This process may be simplified by printing a negative in the form of a light-protective coloured coating on to the fabric which has been previously treated with the dye components and dried. For this purpose most of the metallic oxides and similar substances used as water colours may be used. After exposing to light, the printed-on protective colour and any unchanged azo components are washed off and the process repeated, if desired, with different colours. Half tones may be obtained by a preliminary exposure to light, printing on a lightprotective colour at the places where the half tones are desired, and then completing the exposure to light. If ordinary diazo compounds are employed (other than diazo-sulphonates), which lose their capacity to couple when exposed to light, such as tetrazotized benzidine or tolidine, the materials may be first treated with the tetrazo compounds, then printed with a lightprotective colour pattern, exposed to a light, and finally developed with a phenol or aromatic amine. Two-colour patterns may be produced in a single operation by employing two classes of compounds, one of which form a dyestuff only after exposure to linht, while the others forms & dyestuff only without previous exposure. For this purpose, the material mav be treated with a mixture of a sulphonated diazo compound, coupling component, and nitrophenyl lactic ketone; at the exposed places an azo dye will be formed, while at the unexposed places indigo is formed under the action of phenol-alkali. In the three-colour process, mixtures of sodium phenyldiazosulphonate- and phenol may be used for yellow impressions,. sodium diphenyltetrazosulphonate and resorcin for the red, and sodium ditolyltetrazosulphonate, 1 : 8-aminonaphthol-2 : 6-disulphonic acid and #- naphthylamine for blue. The tone and fastness of the colours may be modified by alter-treating them with metallic salts, such as cupric chloride, ferric chloride and potassium bichromate. This subject-matter does not appear in the Specification as accepted.