The first step in priming is making sure that the substrate will wet out properly by checking the dyne level of the substrate with dyne pens. If the dyne is 42 or higher, then no corona treatment is necessary. However, if it is lower than 42, we recommend that the substrate be corona treated immediately before it is primed. We recommend 2 watts x width of material in feet (12” = 1) x speed in feet. If you are running 120ft per min, and running 12” material, set the corona treater to 240 watts. You can corona treat the material and then check it with the dyne pens to verify that the corona treatment brought the dyne level to 42 or higher. Determining Dyne Level of a Substrate
The most important part of laying down primer is laying down the proper coat weight. This is determined by using an anilox roller with the proper cell depth. For synthetics, we recommend a cell depth of 3.9. The line screen isn’t as important, but 400 is recommended. It is important that the anilox roller is cleaned after use daily (water with 5% ammonia or LEVIA Green Clean), and sonic cleaned at least once every quarter. Cleaning Anilox Rollers If it isn’t clean, it will start to lay down less primer than 3.9, and you may run into ink adhesion issues. As for speed and heat settings, refer to this advice: “with drying temp of around 90c or slightly below, running at around 35 meters per minute or 120 feet per minute.”
Now that you have corona treated and primed the substrate, the next step before printing is to make sure that it was primed properly. You would use a Michem® Indicator solution for that. This video demonstrates how to use the Michem® Indicator solution
Attention California customers: Please view SDS for Prop 65 information.
DigiPrime Primers can be applied via flexo or gravure.
DigiPrime: To check for proper coating coverage with these primers, we recommend Michem® Indicator 001.
Sapphire: To check for proper coating coverage , we recommend the Sapphire Indicator Solution.