Static electricity problems encountered during the printing process of self-adhesive materials is a very annoying thing. The resulting problems, such as hair, dirty spots, adhesion, uneven rolls, etc., will always bother the machine operator. What's more, static electricity in the printing process can make you take a step back, causing you to have a psychological shadow and doubt life, and more seriously static electricity can lead to fire problems in the solvent ink printing process.
Static problems are very common in the printing process, especially in film printing or crystal standard material printing process. Generally, static electricity begins to be generated when the material is unwound. The level of static electricity increases as the material is corona'd. When the paper passes through the rollers, static electricity can be generated at any time due to close contact and gravitational squeezing, which creates strong friction. In severe cases, the sound of static sparks can be heard while the film is being rolled. Especially in winter, when the weather is dry, the static problem is worse. So, how can you prevent static problems during printing?
1 . Sprinkle and mop the floor.
Mopping is the cheapest treatment. It is usually used in winter in shops without humidifiers. Although printing standards require environmental humidity control between 40% and 60%, in winter, especially in the northern winter, many printing companies have a hard time reaching 40% humidity in the workshop. After sprinkling and mopping, the floor dries out quickly. We often see that some enterprises will sprinkle a lot of water on the floor of the workshop in order to prevent the occurrence of static electricity.
2. Directly humidify the material.
In the production process, there is a strange method of humidification, that is, thin iron square bars or thick wooden bars wrapped in cotton cloth (the cotton cloth is wet, equivalent to a wrung-out towel) and placed where the bearing material passes through. In general, this measure is not recommended. After all, it is not easy to control the humidity of the cotton cloth, which will affect the quality of printing.
3. Anti-static layer printing.
Before printing, printing an anti-static coating can also prevent static electricity from being generated at a later stage. Of course, this method will add a color, which is limited. Currently, there are few UV rays, which is not applicable to the labeling industry. In addition, to prevent static electricity, you can add additives to the varnish after printing. The use of a static tester is effective although the test results are not good enough, probably because a good enough additive was not found. If the material supplier is asked to perform a coating treatment, it is usually water-based. Although the results are OK, the material is more expensive. Therefore, it is recommended that additives can be added to the varnish after printing to prevent static electricity.
4. Aerosol humidification.
Early equipment used for industrial aerosol humidification is expensive, but now the price has dropped a lot. Therefore, the conditions of the printing company can configure the equipment in a fixed location, the entire workshop humidification. But be careful: electronic components should not be humid, otherwise the loss is not worth the gain.
The above measures are just some of methods I have seen to prevent static in label material printing process , just for reference only, if there are other good ways to reduce static , welcome to share your opinions with Sinopack.