Screen printing mesh material selection
Today I will continue to introduce you to the relevant knowledge of screen printing mesh, and hope to help everyone.
Before printing and dyeing, it must be processed, such as desizing, singeing, mercerizing, enzymatic bleaching, tattooing, shaping, calendering, protection (such as mildew, fireproof) and soft finishing, depending on the grade, type and characteristics of the finished product. get on.
In Guangdong, everyone regards the printing and dyeing factory as a washing factory. It can be seen that water plays an important role in the operation of the printing and dyeing factory and the amount is extremely large. A factory with a daily output of 300,000 meters of color cloth, the daily water consumption is about 9000m3, except for a small part of it is discharged through steam. Almost all of it contains various dyes and various dyeing materials. If it is discharged into the sewers, it will be serious. polluted environment. However, after adopting the above process, the water consumption can be reduced to 70%, except for pre-dyeing treatment (such as some knitted white cloth, no pre-treatment is required) and post-dyeing finishing water, except for the toner paste, washing the net water, basically No more water is needed.
In addition, compared with the dyes used in conventional printing and dyeing, the utilization of commercial dyes is improved because there is no leakage (washed off by water) during dyeing and fixing. For example, the dyeing rate of reactive dyes can only reach 70%, and the dyeing rate can be increased to 95% after printing and dyeing. In addition, auxiliary dyeing chemicals such as urea, soda ash, caustic soda, yuan Ming powder, starch paste, etc. Can be used at all. The printing machine and the dyeing machine are multi-purpose, which makes the original twist-and-turn process route simple and direct. Of course, energy consumption is reduced, labor is saved, and so on.
The choice of materials for screen printing mesh is the same as for other printing processes. Screen printing also has many parameters to control. Although its process is relatively simple, it also needs to check various parameters to ensure accurate printing results. From the mesh, mesh, net frame to screen tension and other parameters, these must be determined according to the needs of the printed matter.
There are currently two types of mesh used in screen printing: nylon and polyester. Although polyester materials have been widely used around the world, screen printing companies are generally willing to use mesh made of nylon.
Polyester mesh has many unique advantages, such as resistance to solutions, high temperatures, water and chemicals. In addition, when severe external pressure is applied, its physical properties remain stable and the flexibility is low. However, polyester has a lower abrasion resistance than nylon.
Due to its dimensional stability, polyester mesh is ideal for printing jobs that require high registration accuracy, such as printed circuit boards. The disadvantage of the nylon mesh is that the stretchability is large and the tension retention ability is poor. After a period of use, the tension of the screen will be weakened, the screen will be slack, and the printing accuracy will be lowered. Therefore, the nylon mesh is not suitable for a fine product such as a printed circuit board.
Screen printing is a wet printing process that must take into account moisture absorption problems. Nylon absorbs up to 5% of moisture and loses 10 to 20% of its strength. Before breaking, it will be stretched by 26~40%, and the polyester mesh will stretch 19~23% before breaking. Nowadays, high-quality monofilament polyester has become the new favorite of screen printing factory. Smooth, with strong tensile strength and strength. In the wet state, its strength will not decrease. Nylon mesh is now only used when printing irregular surface or solid products.
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