Dye processing technology

The research content of dye processing technology mainly includes the determination and treatment of original dyes, the research of processing aid performance, the design and selection of processing equipment and the research of processing technology.

If the post-processing technology is complicated, it is mainly because its regularity is not strong, there are many personalities, and there are few commonalities, so it is difficult to summarize the quantitative rules. So people say that dye processing technology is a combination of science, technology and experience.

1. Dye processing has the following characteristics

① There are many varieties to be processed. Because dyes are fine chemical products, generally the production tonnage is small, there are many varieties, and there are certain differences in processing methods, so the process and equipment are quite complicated;

②Dyestuff factories need to adjust dosage forms or change varieties according to market conditions, and require processing equipment to have a certain adaptability, multi-functional production equipment, and strong mobility;

③High technical content, post-processing treatment includes many aspects, and also involves many professional knowledge. There are both physical and chemical changes in the processing process, and many factors are interrelated and restrict each other;

④Product quality requirements are high, and commodity dyes have a number of economic and technical indicators. Some have established national standards, with harsh production conditions and stable operation. Operators should have high quality and a strong sense of responsibility.

2. Dye processing involves several aspects

2.1 Analysis of the original dye

The original dye analysis mentioned here refers to the testing and analysis of the physical and chemical properties of the original dye for the needs of dye processing. After years of research, it has been found that post-processing is by no means a simple physical process. Before processing the dye, it is necessary to analyze many indicators such as the intensity, shade, hydrophilicity, crystal form, energy level, and impurity content of the original dye to determine Provide basic data with reasonable processing technology.

After the dye is synthesized, the original dye filter cake is provided for the post-processing workshop through liquid-solid separation. The post-processing workshop first tests the original dye after receiving the filter cake.

Different dye varieties, different synthetic processes, even different manufacturers of the same variety, different production batches of the same manufacturer, product quality may have some differences, each batch of dyes must be fully tested, only in this way can a set Correct processing method.

2.2Processing aids

The so-called dye processing auxiliaries are added during the post-processing of dyes to help improve the performance of specific dye commercial formulations (such as dispersibility, thermal stability, dust resistance, anti-agglomeration, solubilization, etc.) or help increase the yield Substances with fixed properties (such as level dyeing, dyeing promotion, deepening, etc.) and dyeing properties (such as fixation, softness, etc.) on the fiber, enhance heat resistance, maintain or improve dispersion stability, prevent dye aggregation, and help Substances that improve the levelness of dyeing.

Commercial processing is inseparable from additives, and the processing formula cannot be optimized without understanding the properties of processing additives. The correct use of additives can improve the quality of dyes, reduce production costs, and increase the added value of dyes.

In recent years, there have been hundreds of auxiliaries used in dye processing, with the largest amount, and the variety of dispersants that play an important role in the processing results is increasing year by year, and the physical and chemical indicators and economic indicators are also different. For example, lignin dispersants have been able to produce multiple series of varieties with different molecular weights and different sulfonation degrees, and the most suitable varieties can be selected according to needs.

For the processing of non-water-soluble (disperse, vat) dyes, a large number of additives need to be added to adjust the strength and other properties. There are many types of additives, and the properties shown in different dyes are not the same. And physical and chemical indicators determine his scope of use. Only by understanding the performance can it be used correctly, and studying the compatibility of additives to make the additives play the best role in the formulation is one of the content of post-processing technology research.

2. 3Processing equipment

Processing equipment (post-processing equipment) is an important means to complete post-processing operations. Reasonable design and selection of processing equipment are the first conditions for successful completion of post-processing operations. It can be said that the development of post-processing technology is inseparable from the advancement of equipment.

In other words, the development of equipment is also driving the continuous development of post-processing technology. In dye processing, the use of ultrafiltration and reverse osmosis membranes plays an important role in the desalination of water-soluble dyes and the improvement of purity. The development and application of ultra-fine grinding equipment can reduce the particle size of the dye to about 1μm. The application of drying technology and equipment is also very extensive. At present, there are many drying equipment professional manufacturers engaged in the development and research of dye drying equipment, and an independent industrial department has been formed. Domestic drying equipment can basically meet the needs of dye drying.

Some documents often divide processing equipment into the category of chemical equipment and regard it as general equipment for chemical equipment. From the perspective of dye specialty, it should be regarded as special equipment. In the post-processing of dyes, due to the characteristics of dye production and commercialization, the relationship between these factors is very close. General equipment has no special effects when used. The quality of goods depends on the equipment to some extent. Targeted design can give full play to the maximum potential of the equipment.

2.4Processing technology

The processing technology is a comprehensive application of the above three parts. Practice has proved that the same original dyes, auxiliaries and equipment, using different processing techniques to obtain completely different results, we can see the importance of process conditions. It is not difficult to see from the above introduction that these four aspects mark the technical level of post-processing.

Many large foreign companies have their own professionals engaged in research in this area, and some even have more personnel engaged in post-processing technology development than synthesis personnel. If the post-processing technology is reasonable, the purpose of reducing production costs, protecting the production environment, and improving product quality can be achieved.

These four factors are interrelated and restrict each other, and none of them are indispensable. It can be considered that the comprehensive application effect of the above four factors is a concrete manifestation of the level of post-processing technology.