Badanova A.K., Badanov K.I.

Taraz state university named after M.Kh. Dulaty, Taraz, The Republic of Kazakhstan

INTENSIFICATION OF PROCESSES OF DYEING AND PRINTING OF TEXTILE MATERIALS FOR DECREASE OF DUMPS IN WASTEWATER OF THE DYEING-FINISHING ENTERPRISES

 

The wastewater of dyeing-finishing manufactures of a textile industry is subdivided into three basic kinds:

- Industrial, i.e. wastewater after realization of the basic technological processes and waters acting from processes of auxiliary manufactures (a chemistry station, a dye-boiler, a boiler-house etc.);

- Household, i.e. wastewater of shower and sanitary rooms, restaurants etc.;

- Atmospheric, i.e. rain water and water of thawing snow.

The industrial wastewater makes up the bulk part of the enterprise drains. The quantity and the structure of wastewater change depending on the kind of manufacture, assortment and output, dyeing-finishing equipment. For the concrete enterprise the volume and the structure of wastewater may vary considerably during the day. These changes are estimated using the coefficient of hour non-uniformity. The coefficients of hour non-uniformity of a total drain of the cotton enterprises usually change from 1.5 up to 1.75. For the woolen enterprises the coefficients of hour non-uniformity reach up to 3.9.

Dueing-finishing manufactures of the cotton industry are water-intensive manufactures. The norm of wastewater in the cotton-printing factory is 200 m3 per 1 ton of output. In drains there are 120 kg/t of fabric the mineral and 60 kg/t of fabric the organic impurities, 7 kg/t of fabric the synthetic SAS, 8 kg/t of fabric the finishing preparations, 2-3 kg/t of fabric the dyes [1].

The wastewater of dyeing-finishing manufacture differs with significant non-uniformity of inflow and concentration of pollution. It contains all of the substances used in the modern technological processes: bleaches, dyes of different classes, thickening agents, reducing agents, dressing substances, catalysts, softeners, textile-auxiliary substances, equalizers, washing-up liquids, etc.

At dyeing and printing of cotton fabrics the basic part of pollution of wastewater is made by the unfixed dyes. Depending on the nature of dye and used technology their allotment varies from 10 up to 40 %. In the periodic methods the significant portion of dyes remains in a dyeing bath. After the appropriate reinforcement the solution in the dyeing bath can be used for 4-5 times and only after that it would be dumped either on factory clearing structures or in the municipal sewerage system. At continuous ways of dyeing the wastewater is formed from washing a textile material. In addition to the dyes in wastewater the different textile-auxiliary substances (SAS, oxidizers, reducing agents, electrolytes etc.) and fixators of colouring get also. So, for example, at use for fastening preparations DCA, DCC, steady - 2 on the equipment of periodic action in wastewater 50 % of the specified substances depart, and on the equipment of continuous action - 25 %. In case of useing active dyes in wastewater 20-40 % (from the initial amount) of dye, electrolyte, SAS and urea gets. Urea, being dumped with drains in reservoirs, promotes increase the nitrate content. Application of sulphury dyes results in presence of sulphides in wastewater of dyeing shop. The volume of wastewater from sulphury dyeing in modern dyeing-finishing manufactures of the cotton enterprises is 3-4 % of the total amount of wastewater. After printing the drains are formed at the stage of washing of the textile material after fixation of dyes. Besides dyes and textile-auxiliary substances wastewater of printing shops contains thickeners. The thickeners are natural or synthetic polymers requiring additional oxygen consumption for oxidation during clearing. Dyeing station in printing shop causes additional loading on the environment. In the dyeing station wastewater is formed from washing various capacities. In wastewater from printing shop the rests of dyes and textile-auxiliary substances get also from washing tarpaulin in tarpaulin washing installations of printing machines, "the black lining" in washing machines WM - 200 after drawing figure and processing in ripe station.

For knitted fabrics the questions about dyeing and printing are especially urgent. The structure of stockinet is very sensitive to different mechanical influences, including on the part of working bodies of finishing machines. The search of new methods of drawing dyes on knitted cloths with the minimal mechanical action and decrease of dumps in wastewater is the important scientific and technical task.

Printing of knitted fabrics using ultraviolet rays (UV-rays) can be attributed to nonconventional ways of printing. At using ultraviolet rays there is no traditional way of preparation a printing paint and traditional drawing it on a stockinet. When using UV-radiation the solution of dye prepares instead of printing paint. The solution consists of 2-3 components, and the printing ink consists of 7-9 components, and in the printing ink there is a thickener necessarily [2].

In TarSU named after M.Kh. Dulaty at the Department of The technology of textile production the experiments were carried out for printing figures on knitted cloths with coubozol gold-yellow and coubozol dark blue. For each dye it is necessary individually to pick up time of the irradiation, height of an arrangement of the irradiation source, optimum concentration of dye, etc. In the experiments we use the device [3] and determine the optimum parameters of UV-processing for knitted cotton cloths. In the fig. 1 there is shown the influence of irradiation time on the colour saturation of the cotton knitted cloth impregnated with solutions of coubozol dark blue and coubozol gold-yellow YCh.

 

 

Fig. 1. Influence of irradiation time on colour saturation of the cotton fabric impregnated with solutions of coubozol dark blue (1) and coubozol gold-yellow YCh (2)

 

Optimum time of irradiation for dark blue coubozol and golden-yellow coubozol  is 30 seconds. It was established that at use of UV-irradiation the initial background changes unsignificantly: 1.85 % against 2.7 % in the classical method. At use of UV-irradiation the stability of figures’ colouring was 5 points, and on the classical way it was 4-5 points. Color saturation of printed images is above at using UV-irradiation. The use of UV-radiation excludes blur of figures contours. When printing by the classical way the quality of preparation of thickener and printing paint influences on quality of printing. Use of UV-irradiation allows completely to exclude a printing paint. The printing paint is replaced by  solution of two or three components. The UV-radiation allows to show and to fix colouring only in the impregnated places with the established patterns on the surface of a cloth. Therefore, the charge of chemical materials is reduced. The processing in the solution of the oxidizer is excluded. The technological time for drawing the figure is decreased. The comparative characteristics of ways of printing a cotton knitted cloth with coubozol dark blue is shown in the Table 1.

 

Table 1. The comparative characteristics of ways of printing with coubozol dark blue

Method of printing of cotton knitted fabrics

Classical:

         Printing paint, g/kg

Offered:

 Solution with using UV-irradiation, g/l

1. Tragent thickener             628

2. Coubozol                            30

3. Glycerin                              15

4. NaNO3                               15

5. Na2CO3                                2

6. H2O hot                           300

7. Develop solution:

H2SO4 (r=1,84 g/sm3) – 20ml/l +  +urea   5 g/l

8. SAS (for soaping)              5 g/l

1. Coubozol                                 6

2. Sopal                                        0.3

3. NaCI                                      12

4. SAS (for soaping)                   5

Print mode

Printing ® Drying at 70îÑ, t=20 min ® Development t=20 sec ® Processing with cold and hot water ® Soaping 5g/l ® Washing with hot and cold water.

Impregnation at 40îÑ, t=5 min ® UV-processing t=30 sec ® Soaping 5g/l ® Washing with hot and cold water.

 

The carried out researches allow to assume that the UV-radiation can be used for printing figures, ornamental patterns on knitted cloths. Use of UV-irradiation will allow to apply colouring and figures on textile materials on international standards ICE. It considerably will cut down expenses of dyes and textile-auxiliary substances and also will allow to reduce emission of chemicals in wastewater.

 

References

1. Sadova S.F., Krivtsova G.E., Konovalova M.V. Ecological problems of finishing manufacture. /Textbook for high schools edited by Sadova S.F./ - M.: EPD of MSTU, 2002. – 284 p.

2. Badanov K.I. Prospects for the use of UV-radiation for finishing of fulling-felt products. STIC "Ëåãïðîì". "Òàóàð", 1996, ¹2, p. 23-24.

3. Badanov K.I., Dzhumadilova R.M., Sikhinbayev J.T. The Patent of National Patent Office under the Cabinet of Ministers of the Republic of Kazakhstan for "Apparatus for photochemical treatment of textile materials". Author's certificate number 14625, Republic of Kazakhstan, 1997.