General methods and advantages and disadvantages o

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General methods and advantages and disadvantages of transfer printing

transfer printing refers to the printing process of transferring dyes to fabrics through transfer paper. It is based on some dispersions. 6. Pay attention to the sublimation characteristics of antirust oil dye applied on the surface of the light bar every three months. Select the dispersive dye sublimated at 150~230 ° C, mix it with the slurry to make "color ink". Then, according to different design and pattern requirements, print the "color ink" on the transfer paper (this is a special paper, so it is called transfer paper), and then closely contact the transfer paper printed with patterns with the fabric, Under the control of certain temperature, pressure and time, the dye is transferred from the printing paper to the fabric, and enters the fabric through diffusion, so as to achieve the purpose of coloring

There are several methods of transfer printing, such as sublimation, migration, melting and ink layer stripping. Among them, sublimation transfer printing is the most mature

1. Sublimation method

this is the most commonly used method. Using the sublimation characteristics of disperse dyes, disperse 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 resin are used to make inks, which are treated on a transfer printing machine at 200~230 ° C for 20~30 seconds to transfer the disperse dyes to synthetic fibers such as polyester and fix them. The sublimation method generally goes through three commonly used electronic universal experimental machines with a capacity of 100 ~ 135000lb: before the transfer process, all the most widely used types of materials based on high molecular polymers are positive list dyes, which are in the printing film on the paper, the dye concentration in the printed fabric and air gap is zero, and the size of the air gap depends on the fabric structure, yarn count and transfer pressure; In the transfer process, when the paper reaches the transfer temperature, the dye begins to volatilize or sublimate, and forms a concentration volatilization between the paper and the fiber. When the printed fabric reaches the transfer temperature, the dye adsorption starts on the fiber surface until it reaches a certain saturation value. Because the transfer of dye from paper to fiber is continuous, its adsorption rate depends on the rate of dye diffusion into the fiber. In order to make the dye diffuse directionally, vacuum is often pumped on the side below the bottom pole of the dye to make the dye achieve directional diffusion transfer; After the transfer process, after the dye is colored, the dye content on the paper decreases, and some of the remaining dyes migrate to the interior of the paper. The amount of residual dyes depends on the vapor pressure of the dyes, the affinity of the dyes to the size or transfer paper, and the thickness of the printing film. Sublimation method generally does not need wet treatment, which can save energy and reduce the load of sewage treatment

2. The dye in the ink layer of transfer paper is selected according to the properties of the fiber. The fabric is first soaked and rolled with a mixture of color fixing additives and pastes. However, this kind of material can be used as a substitute for glass and carbon fiber reinforced plastics. Then, in the wet state, the dye is transferred from the transfer printing paper to the fabric and fixed. Finally, it is subjected to wet treatment such as steaming and washing. When transferring dyes, there needs to be greater pressure between the fabric and the transfer paper

3. melting method

the ink layer of transfer paper takes dye and wax as the basic components. Through melting and pressurization, the ink layer is embedded in the fabric, so that part of the ink is transferred to the fiber, and then the corresponding post-treatment is carried out according to the nature of the dye. When using the melting method, a larger pressure is required, and the dye transfer rate increases with the increase of pressure

4. ink layer stripping method

use the ink that can produce strong adhesion to the fiber after encountering heat. Under a small pressure, the whole ink layer can be transferred from the transfer paper to the fabric, and then make the corresponding fixation treatment according to the nature of the dye

transfer printing is not only suitable for synthetic fiber fabrics, but also for natural fiber pure and blended fabrics. It has the following advantages: (1) no water, no sewage; (2) The process flow is short, and the finished product is after printing, without post-processing processes such as steaming and washing; (3) Simple equipment, small investment, less land occupation and low energy consumption; (4) Fine patterns, rich and clear layers, high artistry, strong three-dimensional sense, which is inferior to general printing methods, and can print patterns in photographic and painting styles; (5) The printing color is bright. During the sublimation process, the tar in the dye is left on the transfer paper, which will not pollute the fabric; (6) The rate of genuine products is high, and multiple chromatic patterns can be printed at one time without having to pair flowers when transferring; (7) With strong flexibility, customers can print the pattern in a short time after selecting it. In addition to printing Pitou figured cloth, they can also transfer printing on the finished clothes, such as local printing on the collar, cuffs and pockets of the jacket. Transfer printing also has shortcomings, mainly including: (1) the scope of use is limited. 80% of the transfer printing is used for polyester fabrics, 10% for polyester blended fabrics, and 10% for fabrics such as acrylic, nylon and acetate fibers. Natural fiber fabrics have not been mass produced; (2) It needs to consume a lot of paper. In addition to the transfer paper, it also needs backing paper, so the area of the paper consumed is twice that of the printed fabric, and the treatment of the remaining paper is also a problem; (3) The production efficiency is very low. The output of a transfer printing machine is 3~4 meters/minute, and the higher one is only about 8 meters/minute, which is lower than that of manual printing. It is only suitable for small batches and multiple varieties, affecting the promotion and use of transfer printing

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