Environmental dyeing and finishing technology inventory: non-aqueous medium dyeing technology

The problem of dyeing water consumption and wastewater discharge in the textile printing and dyeing industry is outstanding. The use of non-aqueous medium dyeing to stop pollution from the source and reduce reaction by-products is in line with the green development concept. Important non-aqueous media dyeing techniques include organic solvent dyeing and supercritical CO2 dyeing. .

Organic solvent dyeing technology

Solvent dyeing uses organic solvent as the dyeing medium. In organic solvent, the dye is easier to combine with the fiber. The dyeing temperature is lower than the traditional process, which can reduce heat consumption and save energy. The dyeing medium uses organic solvent, no water is needed for dyeing, saving the dyeing process. Water consumption; solvent is incompatible with water, and the waste liquid is easy to recover after dyeing. Most of the solvents used for dyeing in the early days are chlorinated olefins. Because they can not swell fibers and dissolve dyes, they are more suitable for disperse dye-dyed synthetic fibers, but they are prone to redox reactions, which are also serious harm to the environment and health.

Solvent reverse micelle staining is a new solvent dyeing method. The dyeing method is to dissolve the reactive dye in a small amount of water to prepare a high concentration aqueous dye solution, and then disperse it in the continuous phase of the organic solvent to form a reverse micelle. The cellulose fibers are dyed. Professor Liu Jinqiang from Zhejiang University of Science and Technology and others used D5 (decamethylcyclopentasiloxane) as a non-aqueous medium to develop a dyeing method for reactive dye/D5 suspension system.

In addition, Professor Wang Jiping of Zhejiang University of Science and Technology is mainly responsible for the “Non-aqueous Media Dyeing Key Technology Research and Industrialization Demonstration” national key R&D plan project, which is mainly aimed at the huge consumption of water resources and sewage discharge in the traditional dyeing and dyeing industry. The problem of treatment, using two different original key technology systems (silicon-based non-aqueous medium dyeing key technology and polar / non-polar binary non-aqueous medium dyeing key technology) to achieve 95% water saving, sewage The purpose of zero emissions.

Supercritical CO2 fluid dyeing technology

Supercritical CO2 fluid dyeing technology is mainly applied to non-ionic dissolving disperse dyes. The dyeable fibers include polyester , nylon and acetate fibers. They have also been studied for polypropylene and aramid dyeing. Recently, they have been studied for wool and Dyeing of natural fibers such as cotton, among which the most promising primaries are polyester dyeing.

The technology uses CO2 as a dyeing medium to dissolve the dye into the pores of the fiber, so that the dye is quickly and evenly dyed onto the fabric. After the dyeing is finished, the CO2 can be separated from the dye completely, and no operation such as washing and drying is required. The dye can be recycled. Supercritical CO2 dyeing technology does not require additives in the dyeing process, does not use water as a medium, does not require post-dye treatment and post-dyeing, can save energy by about 80%, and the dyeing speed is several times faster than the traditional process, and the efficiency is high. CO2 can also be recycled repeatedly, and the residual dye can be recycled in a powder state, realizing energy saving and environmental protection .

However, there are some problems that need to be solved with supercritical CO2 fluid dyeing. First, the production equipment is expensive, and it is a high-pressure system. The one-time investment is large. Second, the variety of dyes suitable for supercritical CO2 fluid dyeing is not complete enough, and the dyeing process needs further research and improvement.

Magnetron sputtering "dyeing" technology

Magnetron sputtering technology does not require the use of water, steam and chemicals, and there is no environmental pollution. The prepared composite fabric coating is dense and uniform, and the structure is stable, which not only maintains the original softness and take-up of the fabric, but also imparts various kinds of textiles. Features. Magnetron sputtering technology is also useful in dyeing processes to convert metallic materials and their oxides, semiconductor materials or non-metallic materials into composite nanoparticles that are directly sputtered onto the surface of the fabric to produce colors and patterns.