Compiled by James “Jim” Tatum, VP, Drytac liquid coating division
What are the pros and cons of film lamination versus liquid lamination/coating?
There are many types of laminating films with adhesives that range from pressure-sensitive (cold) to heat-activated (thermal and heatset) 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 any of several reasons.
To 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 washes
To 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)
To improve 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
We laminate because it is required for the warranty.
We laminate to build customer loyalty with a special finish.
Because traditional film lamination is more established, I 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 who 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 sq/ft) 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 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"/1.55m) to $95K (80"/2m)
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
Benefits: inexpensive coating equipment, available roll to roll, coatings can be loaded up with UV absorbers and light stabilizers (to provide protection), friendlier to the environment (than solvent coatings), inexpensive, durability warranty systems available, good availability of coatings. Wide range of surface sheens from dead matte to hi gloss.
Negative: Slow (1-5 fpm), not compatible with as many surfaces as UV coatings. Immediate clean up required.
Solvent coatings (not very popular)
Benefits: solvent coaters are priced between waterbase and UV coaters, coating can be loaded up with UV protection, warranty systems available, compatible with many surfaces.
Negative: Solvent coaters or coatings are more expensive, the bi-product is not environment-friendly, flammable, slow (1-5 fpm), separate rooms to contain the coating operation or at minimum an external exhaust system is required. Immediate clean up required.
UV Curable coatings
Benefits: Fast (30-100+ fpm), compatible with many surfaces, available both roll to roll and sheets, liquids are inexpensive and extremely efficient (100% solids), self trimming, cured immediately, good availability of liquid types/sheens, easy to use, easy to clean, warranty systems are under development. Does not require immediate clean up.
Negative: UV coaters are more expensive than other coater/film laminators, and UV curable liquids do not add UV protection to the underlaying media. (Explanation: if you add UV absorbers to UV curable liquids, they would not cure under UV lamps. Fortunately most inks are now very stable and have few issues with fading during typical graphic life span.)
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).
Recommendation: UV Liquid Coating, provided that adding thickness/rigidity is not a major consideration
Laminating photos for photo books
Photo books have become very poplar in recent years. While many photos are finished using film laminates—available in a variety of smooth finishes such as gloss, luster and satin, as well as textured finishes such as linen, canvas and leather—liquid laminates are becoming increasingly popular, especially among the mid- to high-volume producers. Liquid laminates are much faster, less labor intensive, less expensive and in some cases, such as Drytac’s Versa Coater PhotoMate UV, can now also add texture to the images.
Cost of a small format UV liquid coater with texturing capabilities ranges from $29K (17"/43cm), $39K (24"/61cm) to $57K (36"/91.4cm).
Recommendation: UV liquid coater for mid- to high-volume producers
Laminating canvas (Giclee/fine art) inkjet prints
Laminating Giclee and other high end inkjet output on canvas and other media can be done by either a liquid or Heatset, a thin 2-mil conformable PVC vinyl. While very good results can be achieved by the aforementioned film laminates (HP recommends Drytac Heatset Satinex and Mattex on its inkjet canvas), many artists still tend to favor a liquid (aqueous- or solvent-based) as they are more comfortable applying a liquid spray or rolled on coating than a “plastic.” Both film overlaminates and liquids can provide UV protection required when fortified with the proper UV absorbers and light stabilizers.
Typical water-based (aqueous) coatings, depending on the application, range in cost from 2 to 26 cents per square foot. Aqueous liquid sheet-fed coaters cost between $5,000 (17"/43cm) and $8,000 (24"/61cm), and a (48"/122cm) is under development. A 60"/152cm roll-to-roll aqueous liquid coater costs approx. $16,000.
Recommendation: Aqueous Liquid Coating or Heatset overlaminating film
Laminating soft truck sides
While soft truck sides are not as popular in North America as they are in Europe, the application is growing in popularity. Protecting heavy-duty PVC Vinyl graphics up to 10 feet (3 meters) wide is normally done with aqueous UV liquids, primarily due to their long-term outdoor durability characteristics, generally as part of a warranty system. Film overlaminates are unavailable wider than 96 inches (2 meters), are often too costly and not flexible enough for the rigors of constant rolling and unrolling.
Aqueous liquid coaters cost approx. $20,000 for 75"/190cm and $35,000 for 128"/3.25m.
Recommendation: Aqueous liquid coating
Laminating vehicle wrap graphics
Most vehicle graphics printed on vinyl are protected with either a cast/calendared PVC vinyl film or liquid laminate. Film laminates are preferred by some because the additional thickness a film provides may make installation easier. Others prefer liquid because of the lower cost and its conformability. The option of a liquid coating on some of the thinner calendared vinyl (3.5mil) is now gaining popularity due to its lower cost and ease of application. Many companies (Arlon/Avery/Drytac/3M) now offer long-term outdoor warranties using a combination of cast/calendared materials and liquid laminates
Aqueous liquid coaters are $16,000 for 60"/152cm and $20,000 for 75"/190cm.
Recommendation: Film overlaminate or aqueous liquid coating
UV coating may be an option soon as the first wide-format roll-to-roll UV coaters are hitting the market, and warranties are expected to follow soon.
Lamination wall graphics
Most digitally printed wall graphics are protected using liquid laminates because it is difficult to achieve both conformability to heavy textured wallpapers and flame retardancy as is often required for most films.
Recommendation: Aqueous or UV liquid coating.
This list is by no means comprehensive; there are many factors that need to be taken into consideration when deciding on the most appropriate finishing system for your application. Check with your vendor for specific recommendations.
James “Jim” Tatum has over 20 years experience with liquid lamination and is Vice President of Drytac’s liquid coating division. Drytac is a worldwide manufacturer of both film and liquid based finishing solutions.