How to avoid uneven phenomena during the printing and dyeing process is one of the important indicators of the quality of the printing and dyeing process. Leveling agents are additives used to achieve uniform dyeing on the dyed object. One of the functions of the leveling agent is to make the dye be slowly absorbed by the fiber. The second function is to make the dye from the dark part move to the light part when the dyeing is uneven, and finally achieve leveling. Therefore, slow dyeing and dyeing transfer are the two most important functions of leveling agents. In recent years, various new fibers have been widely used in the printing and dyeing industry. At the same time, with the gradual improvement of people’s environmental awareness, various leveling agents have made new developments. The article discusses reactive dyes used in fiber dyes, The development of leveling agents for disperse dyes is reviewed to better promote the research work on leveling agents in my country.
Reactive dyes use leveling agents to dye cellulose fibers. Currently, the proportion of reactive dyes is the largest. Reactive dyes are water-soluble dyes containing reactive groups, which can be used with cotton. Macromolecules such as wool, silk, etc. are chemically combined, so the soaping and rubbing fastness of dyed fabrics is very high. Commonly used leveling agents generally include nonionic surfactants. In addition to nonionic surfactants, anionic leveling agents and mixtures of nonionic and anionic surfactants are also often used in recent years.
1.1 Nonionic surfactants The hydrophobic group of commonly used 1F ionic surfactants can be higher alcohols, higher fatty acids, higher alkyl amines, etc., and the hydrophobic group is above C12. Moreover, long-chain alkyl groups of C16 and C18 are ideal, so that they can form ether bonding, ester bonding, amine bonding and other connection forms with the polyoxyethylene hydrophilic group. Commonly used leveling agents such as Pingpingjia 0, Leveling Agent 102 and Leveling Agent OP have certain leveling effects on reactive dye dyeing areas. Because the long molecular chain of this type of leveling agent contains polyoxyalkyl ether, it can form loose oxygen bonds with hydroxyl (-OH), amino (-NH) and other groups in the dye molecules. On the one hand, it will combine with the dye to form a relaxed complex in the dyeing solution, which will hinder the adsorption and dyeing of the dye, thereby retarding the dyeing; on the other hand, it can enhance the interfacial dye migration and full dye migration of the dye. Further promote uniform adsorption of dyes. For example, WE, a leveling agent for wool, is a fatty amine polyoxyethylene ether, which is non-ionic/weakly cationic. It is mainly used as a leveling agent for reactive dyes for wool. It can increase the amount of color and is beneficial to slow dyeing without affecting the dyeing process. It affects the dyeing percentage and has excellent leveling effect when used in medium, neutral, weakly acidic and metal complex dyes.
1.2 Anionic surfactant Anionic dispersion leveling agent is a dye-affinity leveling agent. Anionic surfactants have the same ion type as reactive dyes. They use pre-occupied dyeing. The mechanism of matting is used to slow down the dye absorption speed. Leveling agent EDER is an anionic leveling agent. Its chemical composition is a compound of aromatic polysulfonates. It is a relatively new anionic leveling agent. Its advantages include: (1) The leveling agent EDER has a certain chelating, dispersing and regulating function for heavy metal ions such as calcium and magnesium, improving the quality of the dye; (2) During the dye adsorption stage, it has excellent Retarding dyeing performance, controlling dye adsorption evenly; (3) During the fixation stage, buffering the pH of the dye bath to ensure smooth and even fixation of dyes and avoiding uneven fixation; (4) No adverse effects on the dye fastness of fabrics. The cotton dispersion leveling agent 40Dx produced by Shanghai Daxang Chemical Industry Co., Ltd. (Daxlang) is a new type of dispersion leveling agent for cellulose fibers dyed with reactive dyes. In addition to having superior dispersion and leveling effects In addition, it also has the effect of preventing secondary agglomeration of calcium, magnesium and other metal ions with dyes to cause dye spots; it does not affect the final color and has low foaming properties. In addition, there are reactive dye leveling agents 640 and Daimian ER, both of which have good leveling properties for reactive dye dyeing.
1.3 Compounds of non-ionic and anionic surfactants. Non-ionic surfactants obtain buffering by combining the oxygen atoms on the polyoxyethylene bond with the dye molecules through oxygen bonds. dyeing effect. At present, most of the nylon leveling agents provided by auxiliary manufacturers are anionic/nonionic composite leveling agents, mainly including nylon leveling agent M-2200 (Hangzhou Meigao Huayi Chemical), leveling agent SWP (Ningbo Xinghua Chemical), Nylon leveling agent N-1l (Shanghai Daxiang Chemical), nylon leveling agent GND (Nantong Sente Chemical), leveling agent FK460 (Beijing Zhongfang Chemical), leveling agent TBW-951 (Guangdong Demei Chemical) , Nylon leveling agent rrs (Wuxi Changsheng Fine Chemicals).
Leveling agent for disperse dyes
2.1 When polyester fabric is dyed with split dyes, the leveling properties are good and all dye fastnesses are very high. At present, polyester dyeing mostly uses disperse dye high-temperature and high-pressure dyeing methods, but it is difficult to dye dark dyes and causes environmental pollution. Therefore, polyester simulation technology and product development have been the most active research topics in the textile industry in the past two decades. Ultra-fine polyester fabric absorbs color quickly, and appropriate leveling agent should be added to the dye bath to promote leveling. The leveling agent must have the following conditions: (1) Good retarding effect; (2) Good dye transfer effect; (3) Good dispersion effect, especially at higher temperatures (such as 80 to 120 ℃) dispersion effect on dyes; (4) does not affect the dye uptake rate and color light; (5) has good stability against hard water and various heavy metal ions. For example, the leveling agent RDP=2000 is made by reacting a polyol with an aromatic acid and then compounding it with an emulsifier. It is a non-ionic and anionic compound leveling agent. RDP-2000It has strong permeability and dye migration properties, and can improve the high-temperature dispersion of disperse dyes to a certain extent. The advantages are: (1) easy application and good results; (2) wide process adaptability; (3) effective suppression of tar spots and color spots; (4) no adverse effects on the color light and fastness of dyes. The new high-temperature leveling agent for polyester WYR-1 is developed using sodium dodecyl benzene sulfonate, sodium dodecyl polyoxyethylene ether sulfate, polyoxyethylene (7) glyceryl cocoate and surfactant WYR. Performance tests and applications show that WYR-l has good dye dispersion, level dyeing, dye migration and dyeing rate, low bubble point and cloud point higher than 100℃.
2.2 Polyester superfine fiber. Compared with ordinary fiber, superfine fiber has the characteristics of small single filament fineness, large specific surface area and high amorphous zone content. It is easy to cause uneven dyeing. Therefore, it is necessary to choose the appropriate fiber. Leveling agents are very important. The leveling agent TF-215 developed by Zhejiang Chuanhua Co., Ltd. can significantly reduce the initial adsorption percentage of disperse dyes, improve the desorption and migration of dyes in the early stage and at high temperatures, and increase the high-temperature dispersion and compatibility of dyes. Traditional disperse dyes can be used for dyeing microfibers in the presence of leveling agent TF-215. In addition, β-cyclodextrin is also an effective leveling agent in research on dispersion dyeing of polyester microfibers. Cyclodextrin is a polycyclic glucose produced through biotechnology through the degradation of polysaccharide starch by cyclodextrin glycosyltransferase. Among them, the special ring structure of β-cyclodextrin can form inclusion complexes with most cationic dyes, allowing them to be released slowly during the dyeing process, slowing down the E-dyeing rate and thus playing a leveling effect. The use of β-cyclodextrin does not affect the final surface color depth and dye fastness of the dye, but it should not be used at the same time as surfactants. β-Cyclodextrin has a moderate ring size, high solubility in water, and biodegradability. It has broad application prospects in printing and dyeing processing. </p
