Development and Application of New Dyeing Technology

At present, the textile dyeing mainly has the following problems: the color fastness, such as wash fastness, fastness to rubbing, fastness to sunlight, and fastness to acid and alkali perspiration, etc., cannot reach higher levels at the same time. The use of dyes due to friction, sweating, etc. during the course of taking poses a threat to people's health; more and more high-performance and high-performance new material fibers, new types of fibers or multi-component fibers have emerged and have been continuously innovated. Textile dyeing processes and dyes need continuous innovation and improvement; textile dyeing process, dyes, can be a serious waste, a large amount of sewage and low production efficiency, more and more traditional methods of dyeing have not met the ecological requirements. Recently, the "Twelfth Five-Year Plan" of the textile industry has pointed out the direction for the development of textile dyeing and finishing, that is, it is necessary to focus on the development of new technologies such as waterless and less watermarking, reuse of wastewater, and integrated application of resources, in order to achieve cleaner production in the industry. , energy conservation, emission reduction and sustainable development provide technical support. Under the guidance of the “Eleventh Five-Year Plan” and “Twelfth Five-Year Plan”, many new ecological dyeing methods and processes have emerged and been continuously improved. For example, cold pad batch dyeing, airflow dyeing, and one-bath dyeing for dyeing have achieved practical results. Some emerging dyeing methods such as supercritical CO2 dyeing and microcapsule dyeing have also gradually matured, and more and more new dyeing vocabularies are constantly appearing in industry terms.

1. Microsuspension staining technology (MSD)

Microsuspension dyeing technology (MSD) is a new type of dyeing and finishing technology owned by the technical research team headed by Prof. Xing Jianwei of the School of Textiles and Materials of Xi’an Polytechnic University. It is a new type of dyeing and finishing technology that has complete intellectual property rights in China and has not been reported abroad. The MSD technology uses microsuspension dyeing auxiliaries in the pad bath to form fine microsuspension particles in the dye molecules and uniformly disperse them in the dye bath, which is then inserted into the fiber and yarn voids by padding. As the temperature of the dye bath rises, the micro-suspension particles gradually disintegrate, releasing the dye into the interior of the fiber and fixing it. Research shows that MSD technology has the following advantages:

①The dye is protected due to the "embedding" of the microsuspension particles. The contact probability of the dye and the alkali agent is reduced, the hydrolysis of the dye is reduced, the amount of the dye used for dyeing the same color fabric is reduced, and when the fiber is dyed/nitrile blended, the dye is also protected and the coloring of different fibers is reduced. phenomenon.

②The dyes are first adsorbed onto the fibers in the form of micro-suspended particles, and then diffused and fixed to ensure that the dyes uniformly dye the fibers. Due to its good levelness, when dyeing protein fibers, it can quickly warm up and dye (3oC/min), which not only effectively reduces fiber damage at high temperatures, but also saves process time and energy consumption.

The micro-suspension dyeing auxiliaries used in the 3MSD technology do not produce chemical effects on the dye molecules, and the color and color fastness of the dyed fabrics are not substantially affected.

At present, Changzhou Moonlight Corduroy Co., Ltd. has successfully carried out micro-suspension pad dyeing of cotton corduroy fabric, and successfully established an annual output of 20 million m of pure cotton corduroy fabric and common pure cotton fabric micro-suspension padding. Dyeing demonstration base. The practical production certificate shows that the average dye saving per 10,000 meters of fabric can be 26.78 kg, and the average amount of waste dye per ton of cotton fabric can be reduced to about 3.6 kg. Microsuspension dyeing technology has the characteristics of environmental protection, energy saving and superior dyeing performance, but the technology is still in the development stage. The research on dyed fabrics is not comprehensive enough, but also limited to protein fibers and cotton such as wool, silk or fox velvet. Fiber, there are few studies on other natural and synthetic fibers. At present, there are not many manufacturers that apply this technology, and it is necessary to strengthen the propaganda of new technologies and expand the scale.

2. Microcapsule dyeing technology

The core technology of microcapsules for textile dyeing is to first make the microcapsules using the dye as a core material. When dyeing, the dye microcapsules are directly put into the dye bath, and the concentration of the dye in the fiber, the dyeing bath and the capsule is used to make the dye continuously release, adsorb, and dye the fibers, thereby achieving no additive dyeing. The use of microcapsule isolation and sustained release not only guarantees better dye homogeneity, but also achieves the “zero” emission of dyes and water-free washing of fibers to achieve clean production.

In China, the Institute of Chemistry and Chemical Engineering of Donghua University has made outstanding researches on the dyeing of disperse dye microcapsules. They conducted a comprehensive study on the dyeing methods, preparation of microcapsules, and corresponding processes and devices and applied for patents. The dyeing of disperse dye microcapsules was first applied to the dyeing of nylon 6, PTT and polyester fabrics. The corresponding parameters such as dyeing temperature, bath ratio, holding time and reuse of wastewater were discussed and studied. The dry and wet rubbing fastness, soaping fastness and stain fastness of the final dyeing product are equivalent to the traditional dyeing process, reaching grades 4 to 5, and the COD and BOD values ​​of the wastewater are much lower than conventional dyeing processes. Recently, Luo Yan et al. further studied non-conditional color matching of disperse dye microcapsules and improved the effect of oligomers in PTT staining. The results show that the microcapsule disperse dyes can improve the compatibility of disperse dyes that cannot be matched under conventional dyeing conditions, and can improve the adverse effects of oligomers on dye lifting performance and dyeing rate in PTT dyeing. This technology has already cooperated with a number of dyeing plants to achieve the success of some of the production scale experiments.