Overview of Dyes for Clothing Washing and Dyeing

1. Sulfide dye dyeing
Sulfide dye is a sulfur-containing fuel that is insoluble in water. When dyeing, sodium sulfide should be used to reduce the fuel to soluble chromosomes. The chromosomes of sulfide dye have an affinity for cotton fibers, which are then oxidized to form fuel that was originally insoluble in water on the fibers and fixed to them, achieving the purpose of dyeing.
Although the application of sulfurized dyes has been reduced due to the strengthening of wastewater treatment and environmental protection requirements, the low price of sulfurized dyes, good water washing and waste retention, and relatively simple dyeing methods are still used for cotton fabric dyeing, especially for dyeing dark colors.
(1) The dyeing process of sulfide dyes can be divided into dye reduction to chromosomes; Chromosomal natural fibers; There are four stages: oxidation treatment, cleaning, and color fixing treatment.
(2) Dyeing prescription and process: A、 Prescription Head Cylinder Renewal Cylinder
Anti brittle sulfide black (200%) 10% 2.5%
Sodium sulfide (50%) 10% 2.5%
Soda ash 2-3 grams per liter
Bath ratio 1:30
B、 Operation process
Add water to the dye vat according to the bath ratio, heat it with steam, and simultaneously add sodium sulfide until boiling. After the sodium sulfide is completely dissolved, add the soda ash and dye into the dyeing vat in sequence. To stir evenly, usually boil for about 5 minutes. After the dye solution is fully reduced and dissolved, the steam valve can be closed for dyeing.
Put the thoroughly washed and moisturized clothes into the dyeing vat for dyeing, and keep flipping them over. After about 5-10 minutes, start boiling and staining neatly. During the dyeing process, do not expose the liquid surface of the clothes to prevent premature oxidation and discoloration.
Frequently flip clothes and continue boiling dyeing for 20-30 minutes before stopping heating to gradually cool down the dye solution.
During the cooling period, it is also necessary to constantly flip the clothes. After 5 minutes, they can be taken out and washed with water.
Wash 3-4 times with water, preferably at two temperatures and two coolings, then dehydrate and air dry.
To prevent long-term brittleness, it is best to treat with hot water at 50 degrees Celsius (containing 2% urea and 1% sodium acetate) for 10 minutes, or boil with 1% laundry detergent water to improve color fastness and increase color brightness.
2. Reactive dye dyeing
The process of dyeing with reactive dyes includes three stages: dye uptake (adsorption and diffusion), fixation, and soap boiling. During dyeing, the dye first adsorbs onto the county fiber and diffuses into the interior of the fiber. Then, under the action of alkali, the dye reacts with the fiber and solidifies onto it. At this time, there are still dye residues on the fiber that have not been bound to the fiber. After treatment such as soap boiling and water washing, the float color should be washed to improve the color fastness.
There are generally three methods for dyeing with reactive dyes: one bath one-step method, one bath two-step method, and two bath method.
The one bath one-step method, also known as the full bath method, involves adding all dyes, dye promoters, alkalis, etc. to the dye solution for dyeing. This method is easy to operate, but due to the high amount of dye hydrolysis, the utilization rate is low and it is not suitable for vat dyeing.
The one bath two-step method involves dyeing in a neutral solution, allowing the dye to fully adsorb and diffuse after a certain period of time, and then adding an alkaline agent for fixation. This method has high dye utilization and good color fastness.
The two bath method involves dyeing in a neutral solution and then fixing in an alkaline solution. Due to the fact that dyeing and fixing are carried out separately in two tanks, this method has a high utilization rate of dyes and can be used for subsequent tank dyeing.
The one bath two-step method is a commonly used method, which involves the following steps: pre-treatment before dyeing - dyeing - fixing - washing with water - soap boiling - washing with water - drying with air.
The amount of dye used during dyeing is determined by the depth of dyeing. The amount of salt used is generally 20-50 grams per liter, with darker colors used more frequently than lighter colors. For even dyeing, salt can be added in two parts, half before dyeing and the other half after dyeing for a period of time.
The dye bath ratio should not be too large to improve the dye uptake rate, but it should not be too low, otherwise it is difficult to achieve even dyeing. Generally, a ratio of 1:20 to 1:30 is used. The dyeing temperature depends on the properties of the dye. X-type is 30-35 °, K-type is 40-70 °, KN type is 40-60 °, and M-type is 60-90 °.
The fixing time is generally 10-30 minutes. The commonly used alkaline agent for fixing is soda ash, with a general dosage of 10-20 grams per liter, and trisodium phosphate is 5-10 grams per liter.
The fixing temperature is determined based on the properties of the dye. The X-type is around 40 °; K-type is 85-95 °; KN type is 60-70 °; M-type is 60-90 °. The fixing time is generally 30-60 minutes
After fixation, it is necessary to thoroughly wash and soap boil to remove floating colors and ensure the color fastness of the dye. The process conditions for soap boiling are: 0.5-1 gram/liter of synthetic detergent; Temperature 90-95 ° C; Time 10-15 minutes; Bath ratio 1:30
3. Direct dye dyeing
The direct dye dyeing method is simple, mainly using roll dyeing. Due to the limitations of dye solubility and dyeing rate, pad dyeing is limited to light and medium colors. Dyeing is generally carried out in neutral or weakly alkaline media, and is not suitable for dyeing cotton in acidic solutions. Silk can be dyed in weakly acidic media. The direct dye roll dyeing process is as follows.
1. Process flow
Scroll → Roll dyeing → Water washing (fixing treatment) → Cold water rolling. Light, medium, dark
2. Dyeing prescription dye 0.2 or less, 0.2 to 11 or more
Soda ash (g/L) 0.5~1~1.5 1.5~2
Salt (g/L) -3-7 7-15
Fixing solution prescription: Fixing agent Y or M (weight% of fabric) 0.8~1.2
30% acetic acid (weight% of fabric) 0.6~1
Number of channels, liquid volume L, temperature ° C
Process conditions scroll -150 60~70
Stain 6-12 and boil 100-150
Wash with water at 200 room temperature
Fixed color 4 150 room temperature -60
Wash with water at 200 room temperature
Upper axis 2--
The weight of each axis depends on different fabric specifications.