Briefly describe the characteristics of dispersion printing and the requirements for dyes
First, the characteristics of scattered printing
1. The disperse printing pattern has the characteristics of vivid flower pattern, meticulous pattern, clear layer and strong three-dimensional effect. Transfer printing can print natural landscapes and artistic patterns.
2. Dispersed printing equipment has the characteristics of simple structure, small footprint, low investment and high economic efficiency. Because the equipment is tension-free, it is suitable for all kinds of thick and thin printing. In addition, the transfer printing can be packaged without post-processing.
3. Disperse printing does not have environmental pollution problems. Since the dry processing does not require processes such as washing, steaming, and drying, no exhaust gas or waste water is discharged.
4. Disperse printing has the advantages of high production efficiency, labor saving and easy operation.
Second, the mechanism of dispersion printing
Disperse printing is mostly used for polyester fabrics. It is a printing method in which the dye is sublimed by heat at a high temperature (about 200 ° C) to agglomerate on the surface of the polyester, and then penetrates into the amorphous region of the fiber macromolecule, and is fixed inside the fiber after cooling.
Third, the requirements of dyes for dispersion printing
For disperse dyes used in dispersion printing, the sublimation temperature should be lower than the melting point of fiber macromolecules and the strength of the fabric should not be damaged. The suitable processing temperature for polyester is 180--210 °C. In this temperature range, the molecular weight of the varieties sublimated by dyes is between 230 and 270. There are generally three types of disperse dyes having a molecular weight in this range.
Fast-dye disperse dye: The temperature can be sublimated at 180 °C, the temperature is increased, the color changes, and the edge will be permeated.
Good disperse dyes: sublimation and color development in the temperature range of 180--210 °C. The hair color curve is flat. The effect of temperature on dyeing is not large, and it is a suitable disperse dye for transfer printing.
Late dyeing disperse dyes: dyes are not very good for sublimation and color development at 180--210 °C. If the temperature is raised, good hair color can be obtained. These dyes are highly temperature dependent when dyed.