The Development Of Reduction Clearing Agent WS And The Research Of Its Application

After dyed with disperse dyes, especially medium or dark color, the terylene should be washed with reduction clearing agent. Otherwise, the requirement for fastness such as fastness to abrasion and fastness to washing will be unacceptable. Reduction clearing can not only remove the stain of fabric surface, but also remove the oligomers of fabric surface to some extent. In dyeing process, because of some factors such as nonuniform temperature or nonuniform agitation of dye bath, the dye defects or streaks may be caused. To solve this problem, the usual way is to remove the dyes of fabrics first and dye it again. In this process, the traditional reductive agent, sodium hydrosulfite, is often used in the reduction washing of dyed terylene and stripping dyes. However, due to some disadvantage such as instability and environment pollution, other reductive agents are replacing sodium hydrosulfite now. To develop a new kind of reductive agent, mix it with surfactants and make sure the using conditions in washing and stripping is the significance and main content of our task.A new type of reductive agent H has been synthesized successfully based on other's experience and several testing. This kind of agent belongs to ramification of sulfmate and will cause little pollution compared with sodium hydrosulfite. Under the condition of low temperature and no caustic soda, the electromotive force of reducing electrode is very high. So no reducing power exists and agent H can be stored stably. With the increasing of temperature and alkalescency, the electromotive force of reducing electrode reduces gradually and reducing power increases.In the development of reduction clearing agent, first we selected several surfactants according to the capacity of removing the oligomers and good emulsification, then mixed these activators and obtained washing agent W. Mixing the agent H and washing agent W, the reductive clearing agent WS was acquired. Agent WS has nearly no reducing power under the condition of no caustic soda exists. But mixed with caustic soda, its reducing power increases.In the washing experiments, the best procedure parameters such as temperature, time, bath ratio and the dose of WS have been obtained. Meanwhile, the influence of procedural parameters on reduction washing has been analyzed and washing effects of both sodium hydrosulfite and agent WS have also been compared. For agent WS, no further soap boiling is required compared with sodium hydrosulfite. In this case, lots of energy is saved.In the stripping experiments, the best procedural parameters such as temperature, time, bath ratio and the dose of WS have been established. The influence of procedural parameters on stripping dyes has been analyzed and the stripping levels of sodium hydrosulfites and agent WS have also been compared.The photos of the section of fiber after reduction washing and before washing and the section of fiber after stripping and before have been taken with microscope.The changes of the fabric's colour cast washed and before washing and the changes of the fabric stripped and before have been analyzed.