The principle and characteristics of textile sublimation transfer printing technology

Sublimation transfer printing technology has developed rapidly in our country and has a wide range of applications. In addition, due to its few investment equipments, outstanding printing effects, no pollution, and resource conservation, there is a huge potential for development in the application prospects.

First, the principle and characteristics of the process

The sublimation transfer printing first uses the printing method to print a special printing dye onto the transfer paper, and then heats and presses the dye onto the fabric. Specifically, it is based on the sublimation characteristics of disperse dyes, select the sublimation temperature range of 180 ~ 240 °C disperse dyes, mixed with the slurry to make color ink, according to the different patterns, pattern requirements, with Ep ~ J, The ink is printed on the transfer paper, and the transfer paper printed with patterns and patterns is brought into close contact with the fabric, processed on a transfer printing machine at 200-230° C. for 10-30 s, and the dye is transferred from the printing paper to the fabric. After diffusion into the fabric to achieve the purpose of coloring. In the process of heating and sublimation, in order to allow the dye to be directed and diffused, a vacuum is often applied to the bottom side of the dyed object, so that the dye can reach the direction of diffusion and transfer, and the transfer quality can be improved.

At present, the technology that is really used for large-scale commercial and industrial digital printing is mainly sublimation transfer printing technology.

With the introduction of domestic sublimation inks with price advantages (Sublimation transfer inks are mainly imported from South Korea and Italy are expensive), and the digitization of printing technology, the application fields of sublimation transfer printing technology have become more extensive. In summary, the dye-sublimation transfer printing technology has the following four characteristics:

1, the printing effect is good.

The fabrics printed using the dye-sublimation transfer printing technology have fine patterns, vivid colors, rich and clear layers, high artistic quality, and strong three-dimensional impression, and are difficult to print with general method printing, and can print photography and painting style patterns.

2. The printed product has soft hand and long service life.

The most prominent feature of dye-sublimation transfer is that the dye can be diffused into the polyester or fiber. The printed product is very soft and comfortable, and the ink layer is basically not felt. In addition, since the ink is already dried during the transfer process, the life of the image is as long as the life of the garment itself, and the printed image does not appear to be worn, which affects the aesthetic appearance of the fabric.

3, the process is simple, the equipment investment is less, the flexibility is strong, the authenticity rate is high.

Sublimation transfer can be a time Ep ~, J multi-color pattern without the need for flowers, according to the individual needs of customers, in a short period of time printed jobs to meet the individual needs of customers.

4, save resources and protect the environment.

Unlike traditional fabric printing, thermal sublimation transfer printing eliminates the need for post-treatment processes such as steaming, washing, and the like. It saves a lot of water resources and has no sewage discharge, saving resources and protecting the environment.

Second, the factors that affect the quality of sublimation transfer printing

1. ink

Sublimation transfer ink is the key material of sublimation transfer technology. It is mainly composed of disperse dyes, binders, solvents and minor additives. Dyes are required to have good sublimation transferability and permeability, to achieve a certain degree of fastness index, molecular weight of 230 ~ 380, sublimation temperature of 180-240 °C, commonly used transfer printing dyes are vat dyes, azo dyes and cationic dyes, etc. . The binder requires low affinity with the dye, easy to release dye gas, and has suitable printing adaptability, preservation and thermal transfer adaptability. The commonly used binder is low-viscosity ethyl cellulose, ethyl hydroxyethyl cellulose ( EHEC), long oil modified alkyd resin, etc. Commonly used solvents are turpentine oil, terpineol, high boiling point alkanols, aramids, cellosolve and the like. The most important feature of dye-sublimation transfer printing is that the dye can be diffused into the fabric fibers and has a good fixation with the fabric fibers. Therefore, the dye-extracting inks with good quality are vivid in color, have strong stability, and have good transfer effect. Currently, sublimation inks are classified into two types, waterborne and solvent based. Most of the sublimation inks are waterborne. Aqueous sublimation inks can be used in various small-format desktop printers and large-format photo machines, while solvent-based thermal sublimation inks are mainly used. On wide-format inkjet printers, the speed and width of inkjet printing are solved. The quality of sublimation inks directly affects the quality of the product. Therefore, it is important to choose high quality sublimation inks.

2. Temperature time

The sublimation transfer printing process requires the temperature to be controlled within the range of 180-230°C, the transfer time is about 1O-30s, and attention should be paid to the reasonable deployment of temperature and time.

3. pressure

Pressure is also one of the important parameters of the dye-sublimation transfer process. For instance, if the pressure is too small, the gap between the fabric and the transfer paper is large, the yarn is circular, and the ink gas molecules collide with the air. The fugitive emission results in poor Ep~, J, and the ink is also easily oozing, the lines are thicker and the patterns and patterns are blurred, and the visual effect is deteriorated; if the pressure is appropriate, the yarn is flat and the fabric and the transfer paper are between The voids are suitable and the transfer coloring effect is good, the pattern is clear, and the lines are smooth and fine; if the pressure is too large, deformations, fuzzing, and changes in the shape of the heavy fabrics are likely to occur, resulting in defects such as rough touch and surface coloration. Therefore, controlling the transfer pressure is critical to the aesthetic appearance of the clear visual effect of the printed pattern. At present, most manufacturers of heat transfer machine pressure adjustment are very convenient, in the actual production of the production process, the operator should conduct a detailed record of the process parameters, find the best transfer pressure of various products, effective for subsequent production and processing guide.

4. other

In addition to ink, temperature, time, and pressure that will affect the quality of the dye-sublimation transfer, there are still some considerations that warrant our attention in the actual production process. The first is the selection of transfer paper, the supplier with stable quality and high reputation should be the first choice for printing companies; secondly, it is necessary to recognize the dye ink before transfer (the pattern on the transfer paper before heating and pressing) and transfer. After printing (pattern on the transfer fabric), the color varies greatly. The dye ink generally looks dark and dull before being transferred. Relying on the high temperature of about 200 DEG C. to restore color, it is necessary to conduct proofing before printing. Finally, during thermal transfer, make sure that the hot press surface, transfer paper, and substrate surface are tightly affixed with no gaps, otherwise the transfer image may be blurry.

Third, look forward to further technological breakthroughs

1. Unversioned

2. Paperless

3. reuse

China is a big producer of textiles. The requirements for the quality and safety of textile printing and dyeing are getting higher and higher. The demand for technical innovation in printing and dyeing is very urgent.