Printing over aqueous coatings


Printers have known for a long time that some aqueous coatings make an excellent primer for offline UV jobs, but more and more “specialty” jobs require foil stamping, gluing [pocket folders], ink jet [address labels], or the ability to go through a laser printer.

Ultraviolet [UV] Coating

aqueous

aqueous

Almost every high-end commercial printer sends a few jobs out to an offline UV printer. While some inks are receptive to UV coating, many are not; and it is impractical to inventory and switch inks for the occasional UV job. A select number of aqueous coatings can be used as UV primer. Printers who use these aqueous coatings can use their normal inks to print a job. Not all aqueous coatings work for this application. Talk to your coating representative to make sure the coating you are using can be used as a UV primer. In most cases, it is a good idea to qualify your aqueous coating, ink, and UV coating as a package.

Useful advice : If the aqueous coating was designed as a UV primer, simply allow the job to sit for 24 to 48 hours. This will allow the ink solvents to volatilize from the sheet, thus improving adhesion.

aqueous

aqueous

Foil Stamping

Many aqueous coatings are foil-stampable. Check with your aqueous coating representative for coatings that are receptive to foil stamping. Again, it is wise to qualify the ink, coating and foil stamp as a package.

Ink Jet

Some printers choose not to “spare out” an area for ink jetting address labels. Usually, water-based ink jets will not penetrate the aqueous coating surface and will smudge. Alcohol-based ink jet usually works well for this application.

Laser Printing

Most aqueous coatings will not re-melt when subjected to a laser printer. In addition, most laser printer inks will not absorb through the aqueous coating and will eventually flake off.

Ink Over Coating

aqueous

aqueous

Occasionally, a printer may choose to print the same side of a sheet twice, inking atop aqueous coating. While not impossible, it is difficult. InkĀ  applied over coating cannot absorb into the sheet and will remain wet for a much longer time. Extra precautions to avoid offsetting should be taken including running small loads and using spray powder.