Softened water to ensure the quality of dyeing water to avoid the role of reactive dyes and hard water c What is the meaning
Activated Dye Dyeing Alkali Use Cellulose fiber When dyed with reactive dyes, the base acts as a catalyst for the reaction between the dye and the fiber, and therefore it is necessary to use an alkali agent to promote the reaction. At this time the type and amount of alkali agent is not the focus, but must pay attention to the management of PH value of dye bath. The optimum PH value at the time of dyeing is based on the dyeing temperature. Generally, the pH value of the medium temperature (60C) dye is set at about 11,5, and the pH value of the high temperature dye is controlled at about 10-11, Control in 12,5 or so. Generally add 20G / L of sodium carbonate can reach 11.
Bath ratio and dyeing It is reported that foreign factories generally use atmospheric pressure low bath dyeing machine for cotton knitwear dyeing processing, low bath than we all know, because the reactive dyes are directly affected by the dye, to improve the dye Utilization and efficient use, the use of low bath ratio conditions for dyeing is extremely effective. In general, the relationship between the bath ratio and the dye uptake rate can be expressed by the formula E = K / (K + L) K = [D] f / [d] s, L = Ws / WfE: Bath D, dye weight, WF: fiber weight; [D] D dye concentration in D dye [D] F: dye concentration on fiber It can be seen from the formula that if the distribution order is fixed The greater the bath ratio, the smaller the dye uptake rate.
Absorbable prescription: What are the areas that must be noted when disposing of dyes with reactive dyes? As the reactive dyes in the reaction group is different, the best dyeing temperature, dyeing prescription also changes. For this reason, first determine which type of dye to use: Reactive dyes compared with direct dyes, direct lower, so it is added in the dyeing of inorganic salts to improve the directness. Usually use 50g / L or so of Glauber's salt (Na2SO4), dyeing different depth of its dosage may be appropriate increase or decrease. In order to achieve leveling effect. Add inorganic salts in batches. Here to introduce the role of alkali agent: alkali is mainly used as a dye and dye to deal with the catalytic role, it makes the dye molecules and cellulose molecules combined. Therefore, it is important that the base is not the base but the pH of the dye after adding the base. Under normal circumstances the pH value of the dye should be 11.5 for the best, usually add 20g / L soda ash PH value can reach 11.5 or so. However, some dyeing and finishing enterprises use caustic soda (NaOH), but because of its strong alkali, PH value adjusted to 11.5 there is a certain, that is not easy to control, so the use of less, but if the quantitative feeding system can be used The When the fabric is stained, it is very effective to add soft softener to the dye bath in order to prevent the rope from being folded. It is difficult to add the metal chelating agent when the water quality of the dyeing water is hard.
If you need a higher PH value available sodium phosphate or sodium hydroxide, the need for low PH value available sodium bicarbonate. Sodium hydroxide is a strong alkali PH value is difficult to control, it is not often used. 4: 19 # blue blue dye problem 19 # Blue is a dye uptake, dyeing fastness has the characteristics of the dye, widely used in the world. This dye belongs to the vinyl sulfone type dye, in the dyeing was sulfuric acid sulfide structure, through the alkali into the vinyl sulfone structure, and then react with the fiber, was sulfuric acid sulfide structure, has a high solubility, but very low affinity , For this reason, the initial rate is extremely low. Vinyl sulfone form when the solubility decreased significantly, but at this time the affinity was significantly improved. The exhaustion rate increased significantly, so in the ordinary dyeing conditions, there will be uneven dyeing phenomenon. Can be solved by the following method. A: Use of surfactants to improve the stability of the dissolution of vinyl sulfone B: batches of salt or alkali addition method 5: 21 # blue coloring and reproducibility of the problems and solutions 21 # blue hair color Mission is the use of copper and titanium Qing, it has the following characteristics A: molecular weight B is easy to gather water-soluble dyes, in the dye did not generally water-soluble state was colloidal. C: its chemical structure contains a lot of isomers, due to different manufacturers, different batches, its structure is also different.
