Digital print technology has had a huge impact on the print market.Compared to days of old, customers can now enjoy better quality prints, smaller runs and faster output. The flexibility of digital printing offers many benefits but it has also led to an incorrect perception among some clients that digital printing is more instant than other more traditional print methods.
Customers expect a fast turnaround, give less lead time and can place significant pressure on printers to deliver jobs yesterday to meet campaign deadlines.
In such a highly competitive market, print companies know that if they don’t strive to provide customers with a fast efficient service and be responsive to customer demands, there will be someone down the road who will. Even though digital printing is fast there are still aspects that take time. One of the most critical steps in print production is print drying time.
Timing is everything
Drying prints for the correct amount of time and in the right way forms a crucial part of the production process.
If you don’t respect this step and you laminate too soon after printing, or if you apply the vinyl to a substrate when the print has not fully cured then you will have a disaster on your hands.
Digital printing with true solvent or eco-solvent ink is solvent printing.
The solvents are used as carriers to get the ink pigments and resins onto the substrate. Once printed, these solvents need to completely evaporate out of the film and adhesive in order to consider the ink fully cured.
Solvents that do not evaporate will remain in the film. Laminating the film too soon will further trap these solvents and this can lead to a variety of unwanted outcomes – shrinkage of the graphic, edge lifting and curling, reduced adhesion, film popping out of recesses and film discoloration.
The solvents can start to attack the PVC, causing shrinkage, waviness of the top sheet, and yellowing. Initially they can make the top sheet very soft and stretchy and applying the film becomes more difficult and later once the solvents do evaporate the film could in turn become more brittle. If the inks are still drying after the film is applied and the print has been cut to the edge of the ink then edge lifting and curl can occur as the inks contract and pull on the film.
Solvents that do not evaporate can also migrate into the adhesive altering the adhesive characteristics and film performance. The adhesive can become more tacky and aggressive. Repositioning the graphic during application becomes harder and films with special adhesive properties for fast and easy application may lose these features, negating any application advantages.
Also, once you have applied the graphic, trapped solvents will compromise the adhesive bond between the substrate and top sheet. Typical effects of this include shrinking, peeling, and adhesive transfer, where the graphic peels off, leaving the adhesive on the substrate.
Any excessive adhesive residue on removal requires more time during clean-up, which impacts on the overall cost of the job.
Solvent retention can also lower the adhesion levels to such a degree that the film will not adhere well to the substrate. If you laminate graphics too soon, that will further trap solvents which will continue to attack the media and adhesive and can cause delamination of the laminate. Whichever way you look at it, solvent retention causes costly, and time consuming, problems that can simply be avoided at the start.
Critically, you must follow the vinyl manufacturer’s recommendations. Not following these guidelines introduces unnecessary risks, risks that will cost you more and damage your business than.
By taking the extra time to dry prints before application you can be assured of trouble free handling and performance and eliminate the possibility of graphic failure.
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