SU97828A2 - The method of obtaining white and color patterns on fabrics dyed with insoluble azo dyes - Google Patents

Description

In auth. St. No. 93493 describes a method for dyeing fabrics with insoluble azo dyes, concludes as follows.

The fabric to be painted is impregnated with an alkaline solution of diazaminol, and then treated with a hot, acidified organic acid, saturated with a solution of a salt. Diazaminol is inactive in an alkaline medium and at an ordinary temperature, while under the action of acid and high temperature the stabilizer is cleaved to form an active diazonium reacting with azotole, resulting in the formation of an insoluble azo dye on the fiber. The saturated solution of the neutral salt is a buffer that prevents the soluble diazonium from converging into the expansion bath.

A feature of the described method is that before treatment with an acidified solution of a neutral salt, the fabric impregnated with an alkaline solution of diazaminol is dried and printed with a thickened solution of rongalite.

With the help of some additional operations to the method according to the basic invention, linen or colored patterns can be obtained on the colored background. To do this, the fabric impregnated with an alkaline solution of diazaminol is dried, printed with a thickened solution of rongalite or a diazotized amine, and then developed with an acidified solution of a neutral salt, as described above. At the same time, in the first case, in places where a thickened rongalite solution is applied, no azo combination occurs, since the diazonium formed during the subsequent development in an acidic medium is destroyed by the rongalite — a white pattern is obtained at these places. In the second case, when printing with a thickened solution of a diazotized amine, the latter is combined with diazaminol azotol, as a result of which an azo dye is formed on the printed places before the fabric is developed with an acidified neutral salt solution. In the subsequent development, an azo dye corresponding to diazaminol is formed only at print free sites.

An example of obtaining white patterns (whites).

a) Obtaining a solution of diazaminol.

60 g of diazaminol;

30 g of alizarin oil;

 caustic soda solution 38 ° Be,

QQA

PP (T of water (cleared) 50 °;

b) Impregnation

The fabric is impregnated with the above solution of diazaminol on a three-shaft plus at 40 ° and pressed in 100%, and then dried in an air drier. Impregnation can be carried out on a roller machine with a spin; in this case, it can be dried on drums.

c) Printing and appearance. Printing thickened solution

rongalite and subsequent drying are usually performed; depending on the color intensity, i.e. on the concentration of diazaminol, rongalitis take 50-100 g per 1 kg of printing ink.

The dried tissue is developed on a wide-bed apparatus, in the first bar, which contains hot (90-95) 28–20% solution of salt, containing 2% acetic acid (80-100%), in the second bar, ike - hot water, in the third - hot soap, in

the fourth is hot, and the last is cold water. In a saline solution, the tissue should be at least 5-10 seconds.

Instead of salt, you can take any other neutral salt, and instead of acetic acid - formic, or its mixture with acetic acid. Upon leaving the wide-angle apparatus, the fabric is wrung out and dried on drums.

Subject invention

Claims (2)

1. A method of obtaining white patterns on fabrics dyed with insoluble azo dyes according to the author. St. Or 93493, using rongaslite, characterized in that before treatment with an acidified solution of a neutral salt, the fabric impregnated with an alkaline solution of diazaminola is dried and printed with a thickened solution of rongalite. 2. A variation of the method according to claim 1, characterized in that, in order to obtain color patterns, a fabric instead of a thickened solution of rongalite is printed with a thickened solution of diazotized amine. Priority p. 1-19 April 1950. p. 2-28 March 1951