The principle of heat sublimation transfer printing

The strap manufacturer tells you that transfer printing refers to the printing process of transferring dyes onto fabrics through transfer paper. It is based on the sublimation characteristics of some dispersed dyes, selecting dispersed dyes that sublimate at 150~230 ° C, mixing them with the slurry to form "color ink", and then printing the "color ink" on transfer paper (this is a special type of paper, so it is called transfer paper) according to different design pattern requirements. Then, the transfer paper with pattern patterns is closely contacted with the fabric. Under certain temperature, pressure, and time control, the dye is transferred from the printed paper to the fabric, and through diffusion, enters the interior of the fabric to achieve the purpose of coloring.

Sublimation method utilizes the sublimation characteristics of dispersed dyes, using dispersed dyes with molecular weight of 250-400 and particle diameter of 0.2-2 microns, water-soluble carriers (such as sodium alginate) or alcohol soluble carriers (such as ethyl cellulose), and oil soluble resins to make ink. It is processed on a transfer printing machine at 200-230 ° C for 20-30 seconds to transfer the dispersed dyes to synthetic fibers such as polyester and fix them.

The sublimation method generally goes through three processes: before the transfer process occurs, all dyes are in the printing film on the paper, and the dye concentration in the printed fabric and air gap is zero. The size of the air gap depends on the structure of the fabric, yarn count, and transfer pressure; During the transfer process, when the paper reaches the transfer temperature, the dye begins to evaporate or sublimate, forming concentration volatilization between the paper and the fibers. When the printed fabric reaches the transfer temperature, dye adsorption begins on the fiber surface, reaching a certain saturation value. Due to the continuous transfer of dyes from paper to fibers, their adsorption rate depends on the rate at which the dyes diffuse into the interior of the fibers. In order to enable directional diffusion of dyes, a vacuum is often drawn on one side below the substrate of the dye to achieve directional diffusion transfer; After the transfer process, the dye content on the paper decreases after the dye is dyed, and some of the remaining dye migrates to the inside of the paper. The amount of residual dye depends on the vapor pressure of the dye, the affinity of the dye to the pulp or transfer paper, and the thickness of the printing film. The sublimation method generally does not require wet treatment, which can save energy and reduce the load of sewage treatment.