How to improve the quality of sublimation transfer printing?
May 19, 2022
The factors that affect the thermal sublimation transfer printing can be divided into the following four categories. By optimizing the following aspects, it is beneficial for us to obtain higher-quality thermal sublimation transfer printing products.
1. Dye sublimation ink
The essential component of sublimation transfer technology is sublimation transfer ink, which is mostly made up of dispersion dyes, binders, solvents, and a little quantity of additives. In addition to reaching a certain fastness index, the dye should have acceptable sublimation transferability and permeability. The sublimation temperature is 180-240°C, and the molecular weight is 230-380. Anthraquinone, azo, and cationic dyes are common dyes used in transfer printing. The binder should be good for printing, preservation, and thermal transfer, and it should have a low affinity for the dye and be able to release the dye gas with ease.
2. Temperature and time
The temperature must be regulated between 180°C and 230°C for the thermal sublimation transfer procedure to occur. It takes around 10–30 seconds to transfer. The ink cannot be totally sublimated if the transfer temperature is too low and the period is too short, which would lower the product's quality. The substrate will be too ironed if the temperature is too high and the duration is too lengthy. The completed product's softness will diminish and the quality will be impacted when the temperature is dropped. It is important to consider the appropriate distribution of temperature and time throughout the sublimation transfer procedure.
3. Pressure
pressure is also one of the important parameters of the thermal sublimation transfer process. Taking fabric sublimation transfer printing as an example, if the pressure is too small, the gap between the fabric and the transfer paper is large, the yarn is round, and the ink gas molecules collide with the air and escape, resulting in poor printing effect, and the ink is also easy to seep. The lines become thicker, and the patterns and patterns are blurred, and the visual effect becomes poor. If the pressure is appropriate, the yarn is flat, and the space between the fabric and the transfer paper is appropriate, the transfer coloring effect will be good. The pattern is clear and the lines are smooth and fine. If the pressure is too large, it is easy to cause deformation, fluffing and morphological changes in heavy fabrics, resulting in defects such as rough hand feel and coloring surface. Therefore, controlling the transfer pressure is very important for printing patterns, clear patterns, and visual effects.
4. Other
Apart from the impact of temperature, time, and pressure on the quality of sublimation transfer printing, there exist several other aspects of the manufacturing process that warrant consideration. The choice of transfer paper comes first. For printing firms, reliable and reputable suppliers are top on their list. Second, it should be understood that there are significant differences between the color after the transfer and the pattern on the transfer paper prior to the dye ink being heated and pressed. Before transfer, dye inks often have a dull, black appearance. High temperatures—roughly 200°C—are needed to bring back color. Proofing must be done in this manner prior to printing production.
Finally, make sure that the hot pressing surface, the transfer paper and the surface of the substrate are in close contact with each other during thermal transfer, and there is no gap, otherwise the transfer image and text may be blurred.
