Key points of chemical material operation
1. Check the accuracy of the prepared dyes and chemicals according to the prescription list. When disperse dyes are used to make materials, generally use cold water to beat them and mix them evenly (stirring with a mixer for about 20-30 minutes), and then dilute them with warm water at 40～45°C before use.
2. Dispersing agent and leveling agent should be boiled and stirred evenly with warm water, and should be used as needed.
3. When encountering difficult dyes such as Disperse Red 3B, Disperse Red Jade S-2GFL, etc., beat and stir in cold water, 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, add dye, run for 10 minutes, dye according to the predetermined heating curve. If there is too much foam in the machine after feeding, in order to avoid damaging the circulation pump, reducing the head or even floating the fabric, a defoamer should be added in time.
Operation points of the dyeing process
1. When dyeing, close the machine cover before heating up, and observe the running condition of the grey cloth in the machine from the glass sight hole at any time, and check whether there are abnormal sounds and phenomena in various parts of the machine.
2. When the temperature is 50～60℃, the disperse dye dyeing is very slow or hardly dyeing.
3. When the temperature is above 80℃, the dyeing speed will increase. Therefore, the temperature should not be too fast when the temperature is between 80 and 130℃.
4. Generally, graded heating and graded heat preservation are used to control the heating rate. This is especially important for Disperse Red 3B, Disperse Red Jade S-2GFL, and Disperse Scarlet S-BWFL, which are easy to cause color stains.
5. When cooling down, the cooling speed should not be too fast to avoid defects such as wrinkle marks and chicken paw marks. Therefore, it is necessary to strictly control the cooling rate.
Generally, the temperature rise rate is based on the principle that the temperature change of the fabric does not exceed 1 to 1.5°C per revolution (referring to the main stage of temperature rise and fall).
The principle of nozzle jet pressure control
1. When the fabric is on the machine, the nozzle pressure can be higher, and when it runs normally, the nozzle pressure can be lower;
2. The greater the fabric thickness or weight, the greater the nozzle pressure and the larger the nozzle diameter;
3. Generally, the ratio of the diameter of the rope fabric to the nozzle diameter is 9:10.
4. When cooling down, it is strictly forbidden to inject cold water into the machine at high temperature to directly cool down.
The main points of washing tank after dyeing
1. When changing to a lighter color after dyeing a dark color, the tank washing agent generally uses 98% caustic soda 4~6kg and sodium hydroxide. Process conditions: liquid volume 2000L, temperature 130℃, time 60~90min.
2. When washing the tank, open all the valves of each pipeline to make the tank washing liquid unblocked. After the heat preservation is completed, the high-temperature sewage will be discharged.
3. When producing medium and long fiber fabrics, the filter screen is brushed once per shift; when producing polyester filament fabrics, the filter screen should be brushed once a day; when producing polyester and other whitening varieties, use light-colored cylinders and brush them.
4. Dyeing vats for red products should be dyed with blue products first, and then washing vats after dyeing to dye 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 whitening variety is produced, it will be invalid.
5. For heavily polluted dye tanks, depending on the contamination situation, use a cleaning agent consisting of a highly permeable polymer detergent, hydrogen peroxide, ammonium bifluoride, oxalic acid and organic acid corrosion inhibitors.