At room temperature
1. Dye The role of dye liquor composition additives
1) Composition: glacial acetic acid, levelling agent SE (or dispersant N), disperse dye
2) The role of additives: ① Glacial acid: glacial acetic acid, levelling agent SE (or dispersant N), disperse dye ② Dispersant N (levelling agent SE) Disperse the disperse dyes evenly in the dye liquor, maintain the stability of the dye in the dye liquor, and prevent the dye from agglomerating. 2. Why should disperse dyes be dyed under slightly acidic conditions (PH=5-6)?
① If the PH value is too low (PH—<4= →dye color=light will change, and the dye uptake rate will decrease. ② If the pH is too high (such as alkaline), the dye will be decomposed and destroyed under high temperature and alkaline conditions, the color will be dark, and the polyester will be damaged under alkaline high temperature conditions.
3. How to add materials for disperse dye dyeing? 1) Chemical method: Cold water beating: warm water (<50℃=stir evenly, dilute and filter before adding it to the dyeing vat for use. ① First add glacial acid (add after dilution) to adjust the PH value (measured with PH test paper). ② Add the dissolved levelling agent and dispersant. ③Finally, add the well-distributed dye. Namely: glacial acid → dispersant (leveling agent) → dye Pay attention to the problem: Check whether the filter screen of the feeding barrel is intact before feeding.
4. Why is the highest dyeing temperature 130℃? Because the dyeing percentage of disperse dyes is the highest at 130°C, the color is bright, level dyeing, and less floating. 1) If the temperature is too high, the dye is easy to decompose and the fiber is easy to be damaged. 2) If the temperature is too low, the dye uptake will be low and the dye penetration will be poor, so the highest suitable temperature for disperse dyes is 130°C.
5. Rising during dyeing: What are the requirements for cooling and why? 1) Heating requirements: Control the temperature rise, otherwise the temperature rises too fast, it will cause the dye to be dyed too fast, and the phenomenon of color difference will appear. ① Colored flowers: refers to uneven dyeing. ② Midway heat preservation (90℃*5') Purpose: to heat up the dye after being evenly absorbed by the fiber to prevent stains. ③ Heating speed: should be slow, generally controlled at 1~2℃/min 2) Cooling requirements: ① Requirement: After dyeing, the temperature will drop below 80℃ (generally controlled at 1~2℃/min) ② If the temperature drops suddenly after dyeing, chicken foot prints (wrinkles) are likely to appear or the fabric feels rough. ③ General operation: After cooling down to 80°C at 2°C/min, perform post-washing treatment. It is strictly forbidden to open the lid and wash with water above 80°C, otherwise safety problems may easily occur.
6. What is the purpose of the 130℃ heat preservation (30~45min)? 1) Purpose: To dye the fiber thoroughly and evenly. Light color: short heat preservation time. Dark color: Long heat preservation time. 2) If the holding time is shorter → it is not conducive to the uniform diffusion of the dye, and it is easy to cause color blur and light color. Dyeing operation points 1. Pay attention to the cleanliness of the high-temperature tank conveying pipeline during dyeing and washing tank. 2. Prepare materials and dyes in advance, generally 20-30 minutes in advance, stir and disperse them evenly for later use. 3. The temperature of the chemical material should not exceed 50°C, otherwise the dye will agglomerate. 4. Check whether the filter screen of the chemical tank is intact before opening the material. 5. It is forbidden to add dyes while heating up. After adding dyes, the fabric should be heated for a certain period of time (such as 5min). 6. The heating and cooling speeds must be strictly in accordance with the process curve to prevent excessive heating and cooling from causing quality problems. 7. After dyeing, the temperature should be naturally cooled to below 80℃ before opening the working door of the dyeing vat to avoid burns.