Development and research status of high temperature leveling agent

High temperature leveling agent classification

High-temperature leveling agents are divided into non-ionic high-temperature leveling agents, anionic high-temperature leveling agents and anionic/nonionic compound high-temperature leveling agents.

Non-ionic high-temperature leveling agents are mostly polyoxyethylene ether structures, and the polyoxyethylene ether segment has an asymmetric amphiphilic structure. Its ethoxy component has a certain affinity for disperse dyes and is combined with dyes during the dyeing process. , to reduce the initial dyeing rate of dyeing and achieve the purpose of leveling. For low cloud point nonionic surfactants, it is easy to associate dyes and coagulate at high temperature. Therefore, nonionic high temperature leveling agents are rarely used alone.

Anionic high-temperature leveling agent can adsorb on the surface of dye particles to form a strong negative charge layer. Due to the strong electrostatic repulsion between charged dye particles, a stable dispersion state is formed, and it has good dispersion and solubilization for disperse dyes. It can reduce the cohesion of the dye and cause the problem of dye spots, which occupies a high proportion in the use of high temperature leveling agents. Anionic and nonionic compound systems have synergistic and synergistic effects, which can increase cloud point, improve high-temperature dispersibility, solubilization and leveling, and are also commonly used in the preparation of high-temperature leveling agents.

Biomass-derived surfactants have the advantages of being renewable and non-polluting, and have become an ideal choice to replace petrochemical-based surfactants. Cardanol is derived from natural cashew nut shell liquid, and its benzene ring structure is connected with an active hydroxyl group, and the para-position of the hydroxyl group is an unsaturated hydrocarbon-substituted alkyl chain. The active phenolic hydroxyl groups in cardanol are easy to be modified, and different kinds of surfactants can be prepared. Among them, cardanol polyoxyethylene ether is widely used, because the biodegradation product of cardanol polyoxyethylene ether does not contain nonyl groups. Phenol, which will not cause ecological harm and environmental pollution, has become an ideal substitute for APEO in the field of textile printing and dyeing.

Development and research status of high temperature leveling agent

Polyester fiber is the world's largest and most widely used synthetic fiber. Due to the tight molecular structure, many crystalline regions, strong hydrophobicity, and lack of reactive groups that combine with dyes, polyester fiber cannot be as atmospheric as other fibers. Dyeing, at present, basically adopts high temperature and high pressure method for dyeing. In order to save resources and improve labor productivity, high-temperature and high-pressure dyeing methods with small bath ratio and fast are often used, but fast dyeing can easily cause uneven dyeing, so high-temperature leveling agents need to be added. With the upgrading of high temperature and high pressure dyeing equipment, the requirements for dyeing bath ratio are getting smaller and smaller, and the selection requirements for high temperature leveling agents are also getting higher and higher.

The early high-temperature leveling agents are mostly alkylphenol polyoxyethylene ether surfactants. These high-temperature leveling agents all contain APEO-like structures. However, APEO is very harmful to organisms and the environment; APEO is very biodegradable. Poor, the degree of biodegradation is 0% to 9%, which is toxic to the environment, and the by-products of degradation are easily carcinogenic and toxic.

In recent years, people's awareness of environmental protection has been gradually strengthened, and textile environmental protection has become a focus of attention of producers and consumers. The content of APEO is an important indicator of whether a product is environmentally friendly in international textile trade. The types of environmental hormones produced by textile dyeing and finishing auxiliaries account for 37% of the internationally recognized hormones. Among them, the content of alkylphenol polyoxyethylene ether (APEO) is the highest in textile testing, ranging from 30 to 100 mg/kg. At present, the raw materials used to prepare high-temperature leveling agents mostly contain APEO. Therefore, domestic and foreign researchers have carried out research and development on commercialized high-temperature leveling agents.