First, dyeing properties of reactive dyes
When dyeing reactive dyes, the dye can be directly dyed to the cloth, and because it has good diffusion ability, it is easy to make the dye diffuse into the fiber, but because it has not yet reacted chemically with the fiber at this time, it is easy to wash off most of the dye with water, so it must be used to promote the chemical reaction between the dye and the fiber, and the dye is fixed on the fiber. The former is called dyeing, and the latter is called fixing.
Second, the operation process of reactive dyes
According to different dyeing requirements, reactive dyes can be dyed by two methods, respectively, rolling and pad dyeing.
1. Dyeing
The dyeing process is suitable for small batch and multi-variety production. It is easy to dye, flexible turnover, can be dyed light, medium and dark. Because of the different types of dyes, the direct size of the fiber is not the same, so the dyeing conditions, fixing temperature, alkali dosage and electrolyte dosage are also different.
The reactive dye dyeing operation is to wash the boiled fabric back and forth with 80 ~ 90℃ hot water for 3 times, and then walk several times with cold water to close to the dyeing temperature, add the dissolved dye for 2 to 3 times, add the electrolyte and then dye 3 to 4 times, and add the fixing agent to dye 5 to 6 times.
Operation process:
Color fixing → cold water → hot water → soaping → hot water → cold water → drying
Xiaobian reminds you that in the dyeing operation, the pH value of the dye should be controlled at about neutral, too high, the dyeing is uneven, and easy to cause the hydrolysis of the dye. After hydrolysis, reactive dyes lose the ability to dye fibers. Therefore, it is necessary to wash twice before dyeing, and some K-type reactive dyes need to be boiled at high temperature. In order to maintain the dyeing and fixing temperature, the dye VAT should be covered to prevent the quality from being affected by steam escape and uneven temperature of the cloth roll.
Solid color with alkali agent, also can be used trisodium phosphate.
2. Pad dyeing
One bath and two bath methods for pad dyeing of reactive dyes.
One bath method: the dye and alkali agent are put together, the alkali agent is baking soda, after rolling by steaming or baking, baking soda is decomposed into sodium formate, so that the pH value is increased, which is conducive to dye fixation, X type reactive dye multi-use one bath method.
Two-bath method: After dipping the dye solution, dipping the color fixing solution containing alkali, and then steaming the color fixing, the alkali agent used can be soda ash or trisodium phosphate, or baking soda can be added in the first bath, and soda ash can be added in the second bath.