Transfer printing principle of thermal sublimation
Transfer printing refers to the printing process in which dyes are transferred to the fabric via transfer paper.It is based on the characteristics of some disperse dye sublimation in 150 ~ 230 ° C disperse dye sublimation, mix it with slurry made from "color," according to different design requirements, "color printing" to transfer paper (this is a special paper, therefore calls transfer paper), and then transfer paper and fabric close contact with decorative pattern design, in a certain temperature, pressure and time control, dye transfer printing paper to fabric, through the internal diffusion into the fabric, so as to achieve the goal of coloring.
Sublimation method is to use the sublimation of disperse dye features, the use of molecular weight of 250 ~ 400, particle diameter from 0.2 to 2 microns of disperse dye and water-soluble carrier (such as sodium alginate) or alcohol soluble carrier (such as ethyl cellulose), oil soluble resin ink, in 200 ~ 230 ° C transfer printing machine processing 20 to 30 seconds, make the disperse dye transfer onto polyester and other synthetic fibers and fixation.The sublimation process generally goes through three processes: before the transfer process, 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 air gap depends on the fabric structure, yarn count and transfer pressure.In the process of transfer, when the paper reaches the transfer temperature, the dye begins to volatilize or sublimate, and forms the concentration volatilization between the paper and the fiber. When the printed fabric reaches the transfer temperature, the dye begins to adsorb on the fiber surface until it reaches a certain saturation value.Since the transfer of dye from paper to fiber is continuous, the adsorption rate depends on the rate at which the dye diffuses into the fiber.In order to make the dye can be directional diffusion, the side of the bottom pole of the dye is often vacuumed to make the dye achieve directional diffusion and transfer.After the transfer process, the dye content on the paper decreases after the dye is colored, and some of the remaining dye migrates to the inside of the paper. The amount of remaining dye depends on the vapor pressure of the dye, the affinity of the dye to the paste or transfer paper, and the thickness of the printing film.Sublimation process generally does not require wet treatment, which can save energy and reduce the load of sewage treatment.
Transfer printing is not only suitable for synthetic fabrics, but also for natural fiber pure and blended fabrics.
It has the following advantages:
(1) no water, no sewage;
(2) short technological process, post-printing is the finished product, no need for steaming, washing and other post-processing;
(3) fine patterns, rich and clear layers, high artistic quality and strong three-dimensional sense, which are inferior to general methods of printing, and can print photographic and painting patterns;
(4) the printing is colorful. In the sublimation process, tar in the dye is left on the transfer paper, which will not contaminate the fabric;
(5) high quality, transfer can be printed more than one color pattern without the need for flowers;
(6) flexibility, customers can select the pattern can be printed in a short time.
Advantages and applications of transfer printing:
Transfer printing has the characteristics of light fastness, water resistance, strong color fastness and rich color, etc. It can be used for printing of clothing, household textiles (curtain, sofa, tablecloth, umbrella, shower curtain, luggage) and other products.The enterprise has hundreds of patterns and fabrics to choose from.