UV coating is a process whereby a polymer resin changes from a liquid to a solid with the help of an ultraviolet light source. UV coating can be a direct replacement for lamination and provides a protective covering that adds value to any document, increasing the vibrancy and richness of its colours (as well as protection from scratching and fingerprints). UV coating may be applied as a gloss, semi-gloss, matte, high-gloss, or in some cases with a special roller as a textured finish to many common applications – such as books covers, brochures, menus, postcards and calendars.
The latest UV coaters are offline units that allow the paper to be inserted through a set of adjustable rollers that applies the UV fluid before it’s “flashed” by the UV lamp. This process is instantaneous. However, it’s not a drying source but rather, a curing process.
Purchasing a UV coater is not something you want to cut corners on, as all of these machines will require ventilation to exhaust the fumes and protection from the actual UV lamps. The UV coating process also requires higher energy use due to high voltage UV lamps and air conditioning requirements. The initial cost and investment for the machine may be high. However, the cost of consumables in the long term is remarkably lower.
This start-up cost may scare some business owners, but the numbers you need to consider for a 12 × 18 document are approximately $.005 versus 25¢ per laminated sheet. The purchase of a UV coating machine can make sense, providing you have high enough volumes and a building with the required power and ventilation capabilities.
Lamination has long been one of the most popular and cost-effective methods to protect printed material. Lamination can be either hot or cold. The application determines which method is used. As a basic guideline, thermal or hot-melt laminate (PET film) is a much lower cost that cold-melt and is most often used for encapsulation (both sides), while cold-melt is almost always used on a single side (with the exception of OPP film). Application also affects your choice in treatment. For instance, paper is perfect for hot-melt lamination as it can withstand heat. Cold laminate is used for the treatment of vinyl or other sign applications (many cold laminates also have additional UV protection for outdoor use).
As the digital print market continues to grow, OPP lamination films (which have long been the standard in high-volume large-format trade laminators) are now available in smaller format rolls (11.5″, 12.5″ width x 1970′ of 1.2 mm thicknesses) in both gloss and matte. OPP is a polypropylene film that gives a high-gloss effect and is typically more economical than standard PET films that have been used for many years. The overall properties gives this film the highest level of clarity and brightness over all other films, producing a finished product with similar quality and look to UV-coated material. This gives the average printer – who does not have it within his or her budget or space to purchase a UV coater – an easier starting point without compromising on quality. OPP Lamination films are ideal for write-on/write-off applications, book covers for presentation, perfect-bound applications and single-sided business cards, to name just a few.
The purchase of small-format laminators is also a cost-effective option. They take up little space, are easy to operate, and can be set up to run as little as a single piece with only minimal heating time.
UV Coating pros and cons
- Low per unit cost
- Coating may be applied to cut sheets, which means no additional trimming of laminate material from the edges.
- High Speed
- More expensive capital expenditure
- Requires ventilation and high power consumption
Lamination pros and cons
- Small-format machines with low-cost entry
- Many machines will do both hot and cold
- Even single pieces can be produced with minimal set-up
- Edges must be trimmed on each piece
- Slower output
- Higher cost per unit piece