Textile color screen printing ink Author: Lu Yunlu
In principle, all inks can be used in textiles for spot color screen printing. Even water-based adhesives can be printed if they are large enough.
 1. Water slurry spot printing. The use of water-serigraphed spot color dot patterns, generally only printed white fabrics, its effect is better than four-color printing, but the cost is higher, due to the printing plate and more. If a dot pattern is printed on both white and colored fabrics, the same screen can be printed with thermoset ink and colored fabrics.
2. Solvent ink spot color dot printing. Solvent inks are characterized by the fact that they do not need to be dried and therefore can not withstand the temperature of the chemical fiber coated fabric. The disadvantage is that the hiding power is slightly lower and pollutes the environment.
3. Thermosetting ink spot color dot printing. Thermosetting textile plastisol ink is the best ink for textile screen printing. Its characteristics are: a. do not dry at room temperature, do not harden, so it will not block the network, you can print a very fine network of dots and lines (regardless of how high the number of screen lines, as long as doing the screen version, thermosetting ink are Can be printed); b. Strong hiding power; c. 100% solid content, can be easily printed thicker ink layer (embossing), compared with the foam printing, high fastness, good elasticity, colorful, angular Neat; d. can be wet and wet fast printing, greatly improving the production efficiency; e. with a variety of textile decorative materials such as: glass beads, plastic beads, plastic sheets, metal flashes, light reflective materials, etc. The combination of special effects of printing; f. low cost, the price of domestic ink is close to the price of mortar, but its coating area is three times the mortar; g. completely environmentally friendly.
Thermosetting textile printing inks are readily available in China. Not only do the major international manufacturers of thermoset inks have entered the Chinese market, but many domestic companies have also introduced thermoset inks, and they basically use imported raw materials. Formulated and produced, and the price is low.
Textile equipment screen printing equipment requirements
 Here mainly talk about the requirements of the equipment for textile and garment printing with thermosetting ink. The equipment is mainly two categories: printing equipment and drying equipment.
Is the printing platen production line currently widely used in domestic printing plants used for thermosetting ink printing? First, it is necessary to look at whether or not the board's surface withstands high-temperature baking. If it is an ordinary glass table, it will definitely not be able to withstand it. Second, is there a drying plate for the platen production line, and is the drying car a far infrared heat source? If it is, thermosetting ink printing can be produced, but the production efficiency is affected by the distance from the printed sheet to the drying oven.
Thermosetting ink printing production is best used rotary double disc clothing printing machine. Rotary double-disc garment printing machine has manual type, 1/3 semi-automatic type (board plate is automatically rotated or automatically scraped), 2/3 semi-automatic type (plate rotation automatically, screen plate automatically landing), more Automatic type. In recent years, many domestic companies have produced and sold products, and foreign products have also entered the domestic market.
 Some people think that thermosetting ink printing must be cured with far-infrared drying equipment. Therefore, thermosetting inks can be cured by any method as long as they can reach a certain temperature. Some manufacturers in the use of thermosetting ink printing technology, the use of conventional methods of heating or low-infrared heating equipment also achieved a hot melt curing effect. However, if high-quality special-effect printing products are printed, there will be poor fastness and discoloration of the fabric.
Far-infrared rays are rays with a spectrum between 0.75-1000 μm and are invisible light. The far-infrared effective area for industrial heating is 2.5-15um. Its characteristics are: fast heat, strong radiation (penetrating power), so far infrared is the best source of baking heat. In the far-infrared effective distance (different in power size), not only the thermal efficiency is high, but also the surface layer of the object is penetrated and heated at the same time within the effective depth. The better the quality of the far-infrared material, the higher its efficiency. Thermoset ink printing, especially special material effect printing, is developed using this advantage of far infrared rays.
 The key to the drying equipment for thermosetting ink printing is the quality of the heat-generating components. The first must be a far-infrared heating element, and the second must be an efficient far-infrared heating element. Far-infrared heating (electricity) mainly includes direct heating and side heating. The traditional far-infrared heating components are of the by-pass type, that is, the heating element (electric heating wire) generates a heat source, and then causes the peripheral (round material) or the side (plate material) far-infrared material to generate a heat source; and the latest technology It is direct thermal type: that is, electric energy directly heats far-infrared materials. Obviously, the direct thermal type is far more efficient than the side thermal type and it can save energy.
There are special instruments for checking far-infrared rays, but it is also possible to carry out a simple test: wear a thick cotton glove and put your hand in front of the heating material. If the surface of the glove is hot and the hand has not felt heat, then the material It is not an efficient far-infrared heating element; if the surface of the glove is heated, the hand feels radiant heating at the same time, and the material is an efficient far-infrared heating element.
温度 Temperature control of tunnel-type high-efficiency far-infrared drying ovens for thermosetting ink printing is also very important. Its main indicator is the positive and negative temperature difference. If the positive and negative temperature difference is 5 degrees, the absolute temperature difference is 10 degrees. If the target temperature is set to 155 degrees, positive 5 degrees is 160 degrees and negative 5 degrees is 150 degrees, ie, the temperature fluctuates between 150-160 degrees. Of course, the smaller the positive and negative temperature difference, the better the stability of the temperature and the better the working condition. Some foreign companies use liquefied gas far-infrared drying furnace, but also because the temperature is easy to control, there is basically no positive and negative temperature difference, but the far-infrared radiation generated by the liquefied gas heat source is not as strong as the far infrared ray generated by electricity. The difference between the positive and negative temperature of the far-infrared drying oven produced by electric energy is 3-1 degrees.
The uniformity of the temperature in the infrared heat chamber of the tunnel-type high-efficiency far-infrared drying furnace, the discharge of the exhaust gas (related to the degree of discoloration of the fabric), and the quality of the conveyor belt are also important. Therefore, we must be careful when choosing a tunnel-style high-efficiency far-infrared drying oven.
三Three heights of textile color screen printing
 1. high quality. The fineness of spot color screen printing and the effect of restoring the image are unmatched by color printing. The advantages of its bright colors and ability to print on any color fabric are also difficult to achieve with four-color printing.
2. high efficiency. Because spot color screening printing is basically based on thermoset ink production, automated printing machines can be used for high-efficiency production. Even with a 16-color pattern, two workers can print 600-800 pieces in 1h. The output of a 2/3 semiautomatic printing machine is close to that of a fully automatic printing machine. Using a hand-rotating double-disc garment printing machine, if there is one worker per swatch and two workers are making garments, the output can reach around 300 pieces per hour. Even if a worker operates a two-disc garment printing machine printing six-color patterns, it can produce 200-300 pieces a day. Its production efficiency is also much higher than the paste printing.
3. High profit. In the market, the retail price of a T-shirt (non-brand name) with glue printing is only 10-20 yuan, while the T-shirt with a spot color printing (non-brand name), the lowest retail price I can see is 45 yuan. The average retail price is around 55-90 yuan. The profits of the two are much different.
As far as printing processing is concerned, the processing fee for glue printing is generally 0.10-0.25, while the spot color screen printing is 2.00-5.00 yuan per piece. Therefore, the profit of the latter is also considerable.
 Textile color screen printing technology has been popular in Europe and the United States, Japan and Southeast Asia have also been widely used. In China's Guangdong Province and Fujian Province, affected by domestic sales of European and American orders and fashion T-shirts, more and more companies are learning and adopting this technology. The clothing printing enterprises in the East China region are currently looking forward to learning and mastering this technology. It is also urgent to upgrade the technology equipment.
Textile color screen printing technology (below)