Most of the gauze used in the color woven cotton dab, such as labor cloth and Yuan Gong, mostly use sulfur dye dyeing. The price of vulcanized dyes is cheap, the color of the dyeing is full, and the water washed is better. It is one of the commonly used dyes of yarn dye.
Sulfur dye contains more sulfur elements in its molecular structure, which is insoluble in water. When dyeing, sodium sulfide must be restored. Solk. In recent years, water -soluble vulcanized dyes and anti -brittle sulfurization have appeared, which has made the application of sulfur dyes new prospects.
1. The main points of dyeing process
(1) Control the quality before processing
Pre -dyeing treatment of yarn is the key to ensuring yarn dyeing quality. The dye dye dye is distinguished and light, and individual dyed yarn needs to be bleached. If the training is poor, the yarn hair effect is poor, or the concentration of the filamentine liquid is different, and the bleaching yarn contains more chlorine and so on will directly affect the dyeing quality. Therefore, before dyeing, the white yarn must be carefully checked, and the whiteness must be uniform. There must be no macular, dark spots, alkali spots, rust spots, stains, and chlorine -containing. After dehydration, the white gauze must be covered with wet cloth to prevent the surface from drying. For the white gauze that is stacked for too long, it must be washed again before dyeing, otherwise it will cause local white or light bars after dyeing.
For the non -cooked gauze that is only cooked with water without alkali, because cotton fat and waxy have not been done, the stacking time should not be too long, especially in the high temperature season. Dalm treatment, severe pickling, otherwise, the dye yarn is prone to shallow and white.
(2) Control the dye temperature
Due to the slow dye dye, high -temperature dyeing is suitable, which is not only conducive to the continuous dissolution of dye particles, and quickly penetrate and spread to the inner layer of the fiber. Generally, the dye -dye dyeing temperature is 75 ~ 80 ° C, the high temperature of hand -dyeing yarn is inconvenient, and the temperature is controlled at 60 ~ 70 ° C. If the temperature is too low, it will affect the upper dye of the dye, the color becomes lighter, and gradually increase the concentration of the dye in the residue, producing the color difference between the cylinder and the cylinder. However, some dyes are suitable for low -temperature dyeing, and the temperature is too high, but it is lighter. This is mainly due to the reduction of the direct properties of the dye to the fiber after the temperature rises. Generally, low -temperature staining is mostly light -colored yarn, such as the latitude of the latitude, sulfur deeper ash, etc. can be dyed at room temperature. In addition, the dyeing temperature is closely related to the light, light -free, and dyeing machinery of the cotton yarn. Generally, the dyeing temperature of the gauze is high, and the silk gauze is lower. High -temperature and high -pressure dyeing gauze has a closed device, and the dyeing temperature can be increased to above 100 ° C. If the temperature of the duplex dyeing machine is too high, it is easy to make the yarn float and cause random gauze and broken gauze. Therefore, most of the dyeing temperature is 70 ~ 80.
(3) Control the concentration of the dye bath
When dye dye dyes dark color, due to the high concentration of dyeing in the dye bath and fast oxidation rate, the unsteady dyes and air contacts on the yarn are adsorbed on the surface of the yarn after dyeing and the yarn. Copper -colored defective diseases have reduced dyeing fastness. In order to obtain a better dyeing effect and dyeing fastness, the general dyeing method is to immediately immerse the yarn taken from the dye bath and restart it again. The concentration of dyeing solution delays the oxidation rate, reaches uniform color, stable quality, or removes the floating color of a part of the color yarn surface by reducing liquid. This process is often called a stuffy tank.
When dye dye dyeing cotton yarn, it is commonly used in dyeing method. Among them, the most black and Tibetan cyan color is the most, and the upper dyeing rate is generally 25%to 30%. Therefore, there are more dyes left in the dye bath. Later residual liquids are usually used continuously. The proportion of the amount between the amount of person and the replenishment of the dyeing of the head cylinder is often referred to as the bonus of the head cylinder dye. If the bonus number is wrong, it will affect the shades of the color of the head and the sequel cylinder. When dyeing light yarn, the number of head tanks can be appropriately reduced. The dyeing dark yarn should be increased. When the upper dyeing rate is 25.4%, the bonus of the head cylinder dye is about 2.5 ~ 4 times that of the continuous cylinder dye.
There are many factors that affect vulcanized dye dyes. In addition to the amount of dyes and sulfide, the yarn is cotton, cooking amount, water hardness, and sulfide content.
2. Example of dyeing process
Table 2-9 is a sulfurized black sulfur to dyeing the silk gauze on the duplex dyeing machine. The yarn weighs 25kg and the bath ratio is 1:40.
The process process is as follows:
Clean water cooking (100 ° C, 3H) → silk glory (21.55%roasted alkali) → neutralization (98%sulfuric acid 2.5 ~ 3g/L) → warm water (40 ~ 50 ℃) → dehydration → stretch (stretch, straight) → Sancker → dyeing (70 ~ 75 ℃, 20min) → temperature cylinder (35 ~ 40 ℃, 5min) → water washing (cold washing, flowing) → draining → anti -crispy treatment (25 ~ 30 ℃, 10min) → out of the cylinder → Bag cloth → dehydration → stretching