The Solvent Cure: Avoiding Digital Printing Problems

How can you avoid solvent related problems when digitally printing  on vinyl?

What customer doesn’t want his job yesterday?  And of course, the customer is always right. So why not give them what they want?

Your natural inclination is to print the job, laminate it, install the graphics and get paid. It makes good business sense, because if you don’t do it, your competitor will.

As the solvent migrates out of the vinyl film, it contracts and afterwards becomes brittle and cracks.

I’m going to tell you why this is not the right thing to do.   It’s probably not what you want to hear, but please hear me out.  I understand rush jobs. In a past life, I worked for a large fleet graphics printer and one of my responsibilities was production planning. There I learned about solvents, vinyl films and curing. I learned that if you don’t cure the solvents before you laminate the print and before you install the graphics, you could be asking for trouble. 

That list of digital printing problems include film shrinkage, edge curl, tenting of the vinyl around rivet heads, channeling of the film in the valleys of corrugations, yellowing of the print media and overlaminate, and transfer of the image to the painted substrate.

The Cure

In avoiding problems related with digital printing with a solvent ink on vinyl, what can you do?

• Create a digital printing profile to suit your environment.  If use a standard digital printing profile for a particular material, don’t be disappointed if you don’t get the results that you expect. A manufacturer’s profile is just a starting point. That digital printing profile will need to be modified because each printing environment is different. The profile that the printer creates should take into account those variables that are unique to him. These include the temperature and humidity of the shop, the barometric pressure, elevation, the thickness of the media and the type of ink.
• Heat settings. Solvent and ecosolvent printers have heaters that perform a variety of functions in the printing process.  Using the right heater setting is critical in reproducing the image.  It also affects the curing of the ink system.  Set too low and the dot grows.   With dot gain the printed image can darken. And   at the lower heat setting the solvent won’t sufficiently cure.  This residual solvent can affect the performance of the vinyl film and its adhesive system. On the other hand, if the heat setting is too high, the dot doesn’t sufficiently grow and the print is too light. More importantly, when the solvent flashes off too fast the ink also doesn’t sufficiently anchor to the film.
•  Ink limits. The volume of ink that you print on a substrate has a direct effect on the dimensional stability of the film that you are printing on. The more ink that you lay down, the more contraction of the vinyl you can expect as the ink dries.  Vinyl manufacturers, such as 3M, Arlon and Avery Dennison, advise their customers to limit ink densities to no greater than 250% to 275%.
• Give the ink time to cure. No matter what you do, you can’t rush manufacturing process.  It’s a lesson that digital printers need to learn and enthusiastically embrace. Regardless of all of the pressures to deliver a job, you cannot laminate before the print is dry.  That means not just dry to the touch, but dry through and through.  Laminating a digital print before the ink is completely cured can trap the solvents between the vinyl media and the overlaminate.  These trapped solvents have to go somewhere.  In some cases, when the solvents outgas from the inks, tiny air bubbles form under the overlaminate.  When this happens, it can look like silvering.  It’s not, because with silvering you can rub the affected area with your thumbnail and it will disappear. Trapped solvents can also result in problems, such as the delamination of the overlaminate from the print,   tunneling and yellowing of the print media or overlaminate.

Vinyl graphics can absorb solvents causing the film to soften and expand.  As the solvent migrates out of the vinyl film, it contracts and afterwards becomes brittle and cracks.  Uncured solvent can also migrate into the adhesive system of the vinyl graphics. This can weaken the bond of the adhesive. By weakening the bond, often the adhesive fails and the film lifts in the places where it has been stretched.

The cure for solvent related problems may be a bitter pill to swallow.  But sometimes taking your medicine is the only sensible option.

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Vinyl Application Videos

Squeegee Technique. Nothing is more basic in vinyl application than the squeegee. But some squeegees work better than others. And there are right ways and wrong ways to use this simple tool. This video clip reviews squeegee selection, squeegee care and squeegee technique. Click to Link

Wet Applications. Dry applications are typically recommended for most vinyl applications. For those exceptions to the rule, this instructional video explains the right way to perform a wet application. Click to Link

Application of Window Graphics. Installing vinyl graphics on glass can be challenging, because the adhesive aggressively grabs onto this high energy surface. Repositioning graphics on window is generally difficult, if not impossible. This instructional video explains how to dry apply window graphics right the first time. It also describes the necessary steps required for surface preparation. Click to Link

Transferring Frosted Window Graphics Films.  Because frosted window films are highly textured, transferring cut vinyl graphics can be problematic. This video provides direction in selection of the right application tape and how to apply these films quickly, easily and without problems. Click to Link

3-Step Surface Prep. This instructional video describes how to properly clean the surface of a vehicle before applying pressure sensitive vinyl graphics to a trailer or doing a full wrap of a car or van. This three step surface prep involves detergent washing, solvent cleaning and a final wipe down with IPA. Click to Link

Vinyl Application Over Rivets. Applying vinyl graphics on vehicle surfaces with rivets is challenging for most sign makers. Vinyl failures to these surfaces are all too common. This video demonstrates some tips and procedures, used by professional decal installers, which will make these demanding applications easier and more trouble-free.  Click to Link

Vinyl Application to Corrugations. Learn how to apply vinyl graphics to corrugations in a relaxed state. Forcing films into the valleys of corrugations puts too much mechanical stress on the film. Sooner or later, the vinyl will lift or tent in valleys. Click to Link

Applying Air Egress Vinyls. Vinyl films with air egress release liners have almost eliminated bubbles and wrinkles from applied graphics. Air egress release liners with their highly textured surface structure are problematic. Not much will stick to these liners other than the vinyl film. At RTape our best premask solution for air egress liners is a special Conform® tape called 4761RLA. Click to Link

About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer.  Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for  publications, such as  Signs Canada, SignCraft,  Signs of the Times, Screen Printing, Sign and Digital Graphics and  Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.  Vinyl Sign Techniques is available at sign supply distributors and at Amazon. 

© 2016 Jim Hingst