There are many types of laminating films with adhesives that range from pressure-sensitive (cold) to heat-activated (thermal) and base films made up of PVC vinyl, polyester (PET), polypropylene (OPP), polycarbonate, and others.
Liquid laminating systems also come in many varieties. Some liquids, such as aqueous and solvent coatings, are cured using ambient, forced air and/or sometimes infrared heaters, while UV curable coatings need UV lamps to cure (harden) the liquid.
When we consider the many reasons for lamination, it becomes clear that the answer to "film or liquid" is not so simple. We over-laminate an image, print, photo, poster, banner, brochure, book cover, for several reasons:
Protect and preserve:
- Prolong the life of image to be laminated.
- Protect the image from fingerprints, smudges, pollution, graffiti.
- Protect the "message" on printed post cards from the mail system's sorters
- Protect bus wraps from weekly "car" washes.
Enhance and beautify:
- To enhance the image by making the surface more uniform.
- To increase the gloss or matte level, or add a special texture (linen, leather, canvas).
Handling and functionality:
- Add rigidity for ease of handling: for example, graphics for pop-up booth or roll-ups.
- Add a slip resistant over-laminate to a floor graphic.
- Add a laminate with a dry erase surface for menu boards.
- Add a coating to make a non printable surface printable
- Required for the warranty.
- Build customer loyalty with a special finish.
Because traditional film lamination is more established, this article will focus on a number of applications where liquid lamination is the method of choice or at least deserves serious consideration.
Laminating Output from UV Flatbed Printers
Most people that have purchased a flatbed UV printer do not plan to laminate their materials. Cutting out the media cost is usually the primary reason for purchasing the printer in the first place.
However, UV Liquid lamination is a very cost effective ($0.01-$0.04 sqft) way to not only protect an image from abrasion, but also to make the finish of the printed board more uniform. This eliminates the banding caused by the direction of the printer heads and adds a high gloss or other finish. There are also specialty coatings the UV liquid coater can apply. There are Anti-Graffiti clear coats, primer coatings for better ink adherence, and a white primer coating that can be applied to avoid having the UV printer print large areas of white.
New to the industry are UV coaters that can do both sheets as well as roll-to-roll coating.
Cost of a UV Coater, depending on the width required and options, ranges from $75K (60 inches/1.55m) to $95K (80 inches/2 m)
Film laminates are a less desirable choice for UV flatbed output because they are significantly more expensive than liquid laminates when compared on a square foot basis. Also, not all film laminates bond well to UV output and the rigidity that the films add is often not needed. Plus there's the waste and trimming factors that are no longer issues to contend with.
Recommendation: UV Liquid Coating
Laminating Brochures, Menus, Fliers, Postcards, Invitations, etc.
These types of prints were traditionally laminated using thermal laminating films (Polyester or OPP film with copolymer adhesive). Small but fast UV coaters are giving thermal laminators a real run for their money. The ease of operation of a UV coater (no need to trim) and the low cost of the UV liquid have made this a real contender for many people operating an HP Indigo, Xerox DocuColor, Canon Image Press, Konica Minolta, Ryobi 4, Heidelberg, and similar digital presses.
If adding rigidity to the image is a major consideration, then thermal film would be a better option as it is available from 1.2 mil (30 micron) all the way to 15mil (375 micron).