Weather- and water-resistant labels withstand harsh elements
By Stacey Wenzel
You wouldn't dare go to the beach without sunscreen, would you? Or brave winter's snow and cold temperatures without wearing a hat and gloves? We all know that we need to protect ourselves from such extreme elements.
The same holds true for labels. If a label can't survive harsh conditions, then it can't perform its job properly. However, with the right protection, labels can withstand some of the most demanding environments.
According to Carl Gerlach, director of marketing for Shawnee Mission, Kan.-based Gill Studios, the outdoor durability of a label or decal typically is affected by two main factors
1. Weathering. This refers to such outdoor conditions as rain and snow.
2. The sun. According to Gerlach, the sun is one of the most damaging elements a label or decal can face. "The sun will fade an ink faster than all the rain you can put on it," he said.
"One of the simplest ways [to make a label weather- or water-resistant] is to use what we call a self-wound, clear polypropylene material," said John Abbott, national marketing manager for Metro Label, Garland, Texas. "If you saw a roll of this, it would look like a large roll of Scotch tape. We laminate this material over the top of the label and the printed graphics. This protects the label from the elements."
Abbott also suggested applying a UV varnish, which is done using a print station on press. "The varnish starts out as a liquid," he said. "It is flood coated over the entire printed label and then rapidly cured using an ultraviolet exposure unit. This cures or hardens the varnish. The cured varnish becomes a very capable protective shield for the label."
A third method Metro Label uses to protect its products is a special catalyzed ink that is resistant to moisture and chemicals. "This ink is printed on a polyester or vinyl material that will withstand exposure to the elements," noted Abbott.
Additional factors, such as the printing process used, can help decide the best way to make a label weather- or water-resistant. Gerlach claimed the two most common methods are screen printing and flexography.
Flexo Vs. Screen Printing
Screen printing differs from flexography because it uses a thick pigmented ink. "Little pigments float in the ink which make it more durable," said Gerlach, adding that the pigmented inks are particularly good at combating damage caused by the sun.
In contrast, flexography uses a water-based ink, which carries more dyes than pigment. "You can only lay down a thin layer of [water-based] ink, so it's not as durable," he advised.
Flexography is used mostly indoors on primary and secondary labels. For example, a shampoo bottle label needs protection from water, but it doesn't demand the durability of a label subjected to outdoor elements, Gerlach said.
Ward/Kraft, Fredericktown, Ohio, produces weather- and water-resistant labels using flexography and has encountered some unique trends and applications, stated Mike West, regional sales manager for labels.
"We are seeing an increasing number of large drum labels change from being impact printed to thermal transfer printed," said West. "This provides more durability for the variable information, plus the [thermal transfer] printers are much less expensive." He added that thermal transfer printers are also more compatible with the synthetic materials and produce higher quality imaging, especially when bar codes are required.
Ward/Kraft has also provided a solution for an end-user who needed a moisture-indicating label on material being transported between the company's steel mill facilities. "We produced a label with a moisture-sensitive area," said West. "The area is a 11ò2à circle and if the area gets wet, ink smears on the label."
He stated that the smeared ink alerts the user that the product has gotten wet, and therefore needs to be handled appropriately.
The company also uses Permafiber for a number of different applications including jobs for a meatpacker, a seafood wholesaler and a parts manufacturer. The advantage of using Permafiber is that it is a moisture-resistant material with properties similar to the paper used to make money, said West. He explained that, like a dollar bill, the material can withstand a lot of abuse.
Through the Years
According to Gerlach, the life expectancy for protected labels can vary tremendously. A screen-printed label used outdoors can last anywhere from three years to 10 years, he noted. On the other hand, a flexo label typically lasts three months to six months when used outside.
"The life expectancy will vary greatly depending on the materials used for the labels and the kind of exposure the label will be subjected to," said Bill Webb, quality manager of product development for Metro Label. "Obviously, an indoor application will last longer than a label exposed to the full range of outdoor climates.
"It is very important that the distributor ask as many questions as possible regarding the use of the label," Webb advised. "It is also a good idea to find out what the end-user expects the life expectancy of the label to be. Sometimes the end-user's expectations and the physical limitations of the label are not compatible."
Webb stressed that if the label is going to run through a printer, it is important to know what kind of printer will be used. Whether it's a dot matrix, thermal transfer or laser printer, the label needs to fit the right application.
"We need to know as much as possible about how the label will be used," said Webb. "This is the only way we have to ensure that we give the distributor a product that will work."
The material used can also determine the durability and life expectancy of a label, according to Gerlach. "Flexo uses paper products, while screen printing never uses paper," he said. "Screen printing uses polyester or vinyl so it is durable outside. It's really the combination of the material and process used. The two together [determine] how long the decal can last outside."
- Companies:
- Gill Studios
- Metro Label
- Ward/Kraft
- Places:
- Mission, Kan.