Sulfur black is a high molecular compound with more sulfur. Its structure contains disulfide bonds and polysulfide bonds, and it is very unstable. In particular, polysulfide bonds can be oxidized into sulfur oxides by oxygen in the air under certain temperature and humidity conditions, and further interact with water molecules in the air to produce sulfuric acid, so that the yarn strength is reduced, the fiber is brittle, and in serious cases, the fiber is completely brittle into powder. Therefore, in order to reduce or prevent fiber embrittlement of yarn dyed with black sulfide dye, the following points must be paid attention to:
1. The amount of sulfur black dye should be limited, and the amount of mercerized special color dye should not exceed 700g/ bag. Because of the high dosage of dyes, there is a great chance of brittleness, and the color fastness is reduced, so it is difficult to wash.
2. After dyeing, it should be fully washed to prevent unclean washing. The floating color on the yarn is easy to decompose into sulfuric acid during storage and cause fiber embrittlement.
3. After dyeing, urea, soda ash, sodium acetate, etc. must be used for anti embrittlement treatment.
4. The yarn is boiled with clean water before dyeing, and the brittleness of the yarn boiled with clean water after dyeing is better than that boiled with lye.
5. After dyeing, the yarn should be dried in time. Because the wet yarn is easy to heat during the stacking process, the content of yarn anti embrittlement agent is reduced, and the pH value is reduced, which is unfavorable to anti embrittlement. After the yarn is dried, it should be naturally cooled to reduce the temperature of the yarn to room temperature before packaging. Because it is not cooled after drying and packed immediately, the heat is not easy to be dissipated, which increases the energy of dye decomposition and acid generation, and increases the possibility of fiber embrittlement.
6. Anti brittle black sulfide dye is selected. Formaldehyde and chloroacetic acid have been added to this kind of dye when it is manufactured. The methyl chloride sulfur anti brittle black made from this kind of dye can make the easily oxidized sulfur atoms into a stable structural state, so as to prevent the oxidation of sulfur atoms into acid and make the fiber brittle.
The absorption rate of liquid sulfur black is higher than that of powder, and the sewage has no sediment impurities, which greatly reduces the cost of sewage treatment and is relatively more environmentally friendly. A large number of data show that the dry and wet rubbing fastness of liquid sulfur black is 0.5 grade higher than that of powder. Liquid sulfur black has been fully oxidized during the production process, and will not be oxidized during transportation / storage. Ordinary sulfur black should be treated with alkali sulfide. Alkali sulfide is the metabolite of mirabilite, and the quality residual is uneven, which introduces a large number of impurities, while the impurity of liquid sulfur black is almost 0, which is more stable than powder sulfur black, and the probability of fabric dyeing error is low.
Environmental friendly liquid sulfur black is mainly used in denim yarn dyeing, embryo cloth dyeing, knitting dyeing, package dyeing, etc. compared with other cotton dyes such as reactive dyes and Shilin, it has the characteristics of low cost and short process flow, and has been increasingly accepted by printing and dyeing manufacturers.
Compared with powdered sulfur black, liquid sulfur black has the following advantages:
1. It is easy to use (according to the operation process of direct dyes) and can be fully colored after washing;
2. It is simple to adjust the color light, which can be adjusted by liquid vulcanization or direct dye;
3. Do not use alkali sulfide for cutting;
4. Environmental protection, small odor and waste water;
5. Direct pad dyeing, dip dyeing and jigging;
6. Take as much as you need according to the actual consumption. The remaining materials can be sealed and put into use after a period of time. It avoids the waste of the leftover part of powdered sulfur dyes due to excessive opening;
7. The color light of powdered sulfur dyes is quite stable, and the cylinder difference is serious, while liquid sulfur dyes do not have this phenomenon.
Post time: Jul-15-2022