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, than no Corona treatment is necessary. However, if it is lower than 42, we recommend that the substrate is 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, I would 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 works best for DigiPrime), and sonic cleaned at least once every quarter. Cleaning Anilox Rollers . If it isn’t then 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 Patrick’s advice here…“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 the DigiPrime Indicator Solution for that. Here is a video that we made on how to use the DigiPrime indicator solution .
DigiPrime Primers can be applied via flexo or gravure.
DigiPrime: To check for proper coating coverage with these primers, we recommend the DigiPrime (MI-001) Indicator Solution.
Sapphire: To check for proper coating coverage , we recommend the Sapphire Indicator Solution.
Topaz: To check for proper coating coverage , we recommend the Topaz 17 Indicator Solution.