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Liquid Courage: Coating Technology for Print Protection

(February 2008) posted on Wed Feb 13, 2008

Liquid lamination offers graphics producers the ability to protect prints at a competitive cost and minimize waste and labor in finishing. Read on to find out more about the technology and the applications for which it is suited.

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By Ben P. Rosenfield

Other unique applications that benefit from liquid lamination include doors, furnishings, wall coverings, decor, and even food packaging. Giving products like these, as well as graphics intended for more conventional uses, the protection they need means you’ll have to carefully pair them up with the appropriate coating formulation. Let’s take a look at effective ways to match up coatings and prints.


Selecting the right liquid

It’s no secret that exposure to ultraviolet light cures UV inks and coatings, but it’s that property that prevents UV-curable liquid laminates from offering graphics protection from sun damage. Any sort of UV inhibitor would prevent the coatings from curing. Therefore, the primary purpose of UV liquid laminates is to shield printed graphics from scratching and abrasion. Tatum notes that UV-curable coatings work very well on graphics produced on UV inkjet printers. He says in most cases water-based coatings don’t work as well on UV inkjet prints because cured UV inks tend to act as non-stick surfaces.

Harris advises those who print solvent or eco-solvent inks to use waterbased liquid laminates. He says the basic rule to follow is to reverse the coating— for example, to use a water-based coating on a solvent inkjet print, and vice versa. “And when you’re using water-based coating on outdoor media, like vinyl, it tends to get absorbed a lot easier because of the precoat on the media. Although it won’t run the inks, it won’t give as good protection as it would on uncoated media you’d use with a solvent inkjet printer,” he explains.

One thing to keep in mind is that water-based liquid laminates, like aqueous screen-printing inks, do contain some solvents. As mentioned earlier, the VOC content of these coatings has dropped over the past few years—even in products designed for stain and graffiti resistance; however, you should make sure to keep an MSDS on site for each water-based coating you use.

Solvent liquid laminates are most often applied to water-based prints. They may be formulated with components that absorb UV light, as well as stabilizers that inhibit polymer degradation caused by photo-oxidation or thermal exposure. Solvent coatings also may contain leveling agents, which promote smoothness in a coating’s surface.


Cost considerations


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