The Durability of Latex Inks
As sales of solvent and ecosolvent printers decline, latex printers are growing in popularity. The print quality of these printers is outstanding. What's more, because latex inks are water-based, they provide printers with a much greener solution. Low VOC levels mean that no expensive ventilation systems are required. These inks are not only safer for the operator, but they have less impact on the environment.
Compared to other inks, latex inks are also very durable. Because latex inks are comprised of pigments rather than dyes, their fade resistance when exposed to the sun's UV rays is much greater. While pigments last longer than dyes in an outdoor application, they won't last forever.
Eventually, colors will succumb to the bleaching effect of sunlight. What's more, the lightfastness of latex inks varies depending on several factors, including the formulation of the ink, the media used and the intensity of the UV light. Other outdoor factors in the atmosphere, such as ozone, salt air, humidity and air pollutants also affect the longevity of any ink, including latex inks.
Because many factors affect UV resistance, any claims that a printer or ink manufacturer make about the lightfastness of their inks must be regarded as general estimates of performance. Typically the guidelines that the manufacturer provide are not statements of warranty.
Scratch and Abrasion Resistance
Since the introduction of the first latex printers about seven years ago, inks increasingly become more lightfast, scratch and abrasion resistant and more chemical resistant. Signage, window treatments and wall graphics are generally not subject to excessive abrasion.
Fleet graphics are another story. Printed emblems and vehicle wraps should always be protected with an overlaminate or a liquid clear coat regardless of how the graphics are printed. Vehicle graphics often come in contact with bush and tree branches, as we as stones, gravel and sand on the road. Without protection, these materials will eventually scratch and abrade right through the ink to the base material. Laminates with UV inhibitors will also protect graphics from sunlight. In many cases, it can extend the outdoor life of a latex ink from three years to five years.
Repeated exposure to water, grease and chemicals can also tax the ink system. Although latex inks are water based, they are typically water resistant. Cleaning chemicals, isoproply alcohol, gasoline and diesel fuel can damage printed graphics.
Although today's latex inks are generally robust and resistant to UV light, scratches, abrasions and chemicals, fabricators should carefully examine the application before engineering their project. In your examination, you should question the prospective customer thoroughly. If the graphics are used outdoors, make sure that you understand the degree to which it is exposed to sunlight. With respect to cleaning, determine which chemicals are used and their frequency of use. Finally, by understanding how the graphic will be used, the duration of the program and the customer's expectations, you can better satisfy the needs of the customers.
This article was written by Jim Hingst for RTape Corp. and posted on Hingst Sign Post.