1. Main points of chemical operation

 

1. Check whether the prepared dyes are accurate according to the prescription list. When disperse dyes are made into materials, they are generally first beaten with cold water and stirred (about 20-30 minutes by a mixer), and then diluted with warm water at 40 to 45°C when used.

 

2. Dispersing agent and leveling agent should be dissolved in warm water and stirred well, and they should be dissolved as needed.

 

3. When encountering difficult dyes such as disperse red 3B, disperse ruby ​​S-2GFL, etc., beat the paste with cold water and stir well, and dilute with warm water.

 

4. The feeding sequence is to add acetic acid at about 40 °C, run for a while, adjust the pH value to 5-6, then add dye, and after running for 10 minutes, dye according to the predetermined heating curve. If it is found that there is too much foam in the machine after feeding, in order to avoid damaging the circulating pump, reducing the lift or even making the fabric float, a defoamer should be added in time to defoam.

 

Second, the operation points of the dyeing process

 

1. When dyeing, close the machine cover before heating up, observe the operation of the grey fabric in the machine through the glass viewing hole at any time, and check whether there is any abnormal sound or phenomenon in each part of the machine.

 

2. At 50~60℃, disperse dyes dye very slowly or do not dye at all.

 

3. When the temperature is above 80 °C, the dyeing speed is accelerated, so the temperature should not be too fast between 80 and 130 °C.

 

4. Generally, graded heating and graded heat preservation are used to control the heating rate, especially for disperse red 3B, disperse ruby ​​S-2GFL, disperse scarlet S-BWFL, etc., which are easy to cause color stains.

5. When cooling, the cooling speed should not be too fast, so as to avoid the formation of defects such as wrinkle marks and chicken paw marks. Therefore, it is necessary to strictly control the cooling rate.

 

Generally, the heating rate is based on the principle that the temperature of the fabric does not change by more than 1 to 1.5 °C per cycle (referring to the main stage of heating and cooling).

 

3. The principle of controlling the nozzle injection pressure

 

1. When the fabric is on the machine, the nozzle pressure can be larger, and when the operation is normal, the nozzle pressure can be smaller;

2. The greater the thickness or weight of the fabric, the greater the nozzle pressure and the larger the nozzle diameter;

3. Generally, the ratio of rope fabric diameter to nozzle diameter is 9:10.

4. When cooling down, it is strictly forbidden to inject cold water into the machine to directly forcibly cool down when the temperature is high.

 

Fourth, the main points of washing the tank after dyeing

 

1. When changing to light color after dyeing dark color, generally use 98% caustic soda 4~6kg, insurance powder as the cleaning agent. Process conditions: liquid volume 2000L, temperature 130℃, time 60~90min.

2. When cleaning the tank, open all the valves of each pipeline to make the tank cleaning fluid unobstructed, and discharge the sewage at high temperature after the insulation is completed.

3. When producing medium and long fiber fabrics, the filter screen is brushed once per shift; when producing polyester filament fabrics, the filter screen is brushed once a day; when producing whitening varieties such as polyester, a light-colored cylinder is used and washed.

4. After dyeing the dye vats of red products, you should first change to blue products, and then wash the vat after dyeing before dyeing white varieties. Otherwise, the whitening fabric produced is not only poor in whiteness, but also has red light, even if it is brushed two or three times before the production of whitening varieties, it is ineffective.

5. For the heavily polluted dye vats, depending on the contamination situation, use a cleaning agent composed of highly permeable polymer detergent, hydrogen peroxide, ammonium bifluoride, oxalic acid and organic acid corrosion inhibitor for cleaning.