Tough Duty Labels

By Michelle Sartor | March 27, 2007

Labels that need to withstand difficult environments require the right substrates and adhesives to perform properly.

Some labeling applications require more strength and resistance than traditional labels. These constructions, which we'll call tough duty labels, are used in a variety of environments including those with extreme temperatures, moisture and chemical exposure. Oftentimes tough duty labels carry warnings on products such as heavy duty machinery and therefore need to withstand the conditions the equipment is exposed to. Without the proper labeling material, human safety can be put at risk.

According to Art Bowers, general manager of GSI Technologies' Industrial Graphics Division, Burr Ridge, IL, USA, tough duty labels can be found on electrical, industrial, commercial, mechanical, and automotive products or components. He says, "The labels have to be tough duty because the products they're mounted on are tough duty. These are products that are exposed to the outdoors, to extremes in temperatures (high or low), harsh chemicals, cleaners or solvents, UV rays, and moisture."

A warning label found on a lawn mower, courtesy of Avery Dennison.
Gary Gallas, president of Andrews Decal Company in Chicago, IL, USA, says, "Products that we have printed have been used on power tools, sporting goods, some toys, and some outdoor power equipment like lawn mowers and snow throwers." He also cites heating and ventilation systems, consumer type electronics and some vehicle applications, such as parking registration stickers for outdoor use, as applications for tough duty labels.

According to Jo Ann Logan, purchasing for Consolidated Label in Longwood, FL, USA, "Products that require tough duty applications would be under the hood of a car, nautical equipment and boat applications, test tube marking, hazardous chemicals, battery applications, central air conditioner units that are outdoors, outdoor power equipment like mowers, chainsaws and leaf blowers, and shovel handles."

Serhat Kotak, marketing director, Industrial Labeling Systems in Chelmsford, MA, USA, says tough duty labels are used on many products that are in harsh environments. "Products may be exposed to chemical solvents, heat, cryogenic environments, solvent based washes, lab environments with chemicals, electronics manufacturing processes, aerospace applications (space shuttle, military jets, etc.), automotive applications (labeling brake discs, engine parts, etc.), and outdoor applications such as instruments deployed at oil rigs in the North Sea or Alaska or Arabian Peninsula."

Tough duty labels are typically more functional than aesthetically pleasing, as are many consumer product labels. Bowers says, "Tough duty labels are normally used to convey warnings, give instructions for operation and to label the function of a switch, dial or knob."

An assortment of tough duty labels found on tools, courtesy of Andrews Decal Company.
Since tough duty labels often convey warnings and other critical information, they must stay intact and readable for the life of the product. The labels must therefore be able to withstand the conditions the actual product is subjected to. Logan says, "Tough duty labels are subjected to a variety of conditions: water, grease, acid, dirt, textured substrates, recycled containers, waxed corrugated, painted metals, freezing temperatures, chemicals, and ultraviolet rays."

Dan Ray, general manager at WS Packaging in Algoma, WI, USA, cites harsh chemicals, detergents, salt water, and weather as specific conditions that tough duty labels are exposed to.

The ability to stay readable is extremely important. Gallas explains, "Probably one of the most important things is sunlight or UV radiation. Typically people are very concerned that the label does not fade out. If the label is on tools or outdoor equipment, it could also be exposed to oil or gasoline and different types of cleaning solvents."

Materials used

The construction of tough duty labels allows them to withstand the difficult environments they are exposed to. The most common substrate materials are vinyl, polyester and polycarbonate films. Kotak adds polyimide to that list. Logan says polypropylene might suffice for certain applications. "Any outdoor application subjected to the elements requires a film product rather than a paper product," she says.

According to Bowers, "Tough duty labels are normally constructed of the following components: a base material upon which the label is printed; an adhesive to affix the label to the machine or component; the ink with which the label is printed; and perhaps a film that is laminated over the printed surface to protect the ink. There is a wide selection of materials available so that every tough duty label can be custom designed around the application. These materials range from papers to vinyls and polyesters. There are various coatings that can be applied to these materials by their producers to enhance performance."

Adhesive type is a critical part of tough duty label construction. Logan explains, "In some instances, a general purpose acrylic or rubber based adhesive will work while some applications may need a more aggressive adhesive. Generally speaking, an acrylic adhesive is more aggressive ultimately whereas a rubber based adhesive will stick better at first. Sometimes there could be a need for an adhesive that provides a higher or lower service range temperature requirement than normal as well as lower than usual application temperature."

A variety of adhesive options are available to converters for different purposes. Bowers says, "Sometimes an adhesive has to withstand temperature extremes. An adhesive that does very well at room temperature indoors is probably not made for outdoor use in bright sunlight or ultra high or low temperature and humidity environments. Adhesives also have to be sensitive to the characteristics of the surfaces upon which the labels are to be mounted; for example, a pebbled or powder coated surface."

Gallas says that most tough duty labels are coated with high performance adhesives. "We usually use adhesives that are aggressive, have a lot of initial tack and that work well on a variety of surfaces. Occasionally you get a situation where someone is putting a label on a rougher textured surface. Then you use an adhesive with a thicker coat weight," he says.

Ink is another component that needs to be taken into consideration. Bowers says, "Inks have to be, in some cases, specially made to resist fading in UV light outdoors or to resist chemicals or cleaners. We sometimes use UV cured ink or auto-grade UV cured inks with resistance to fading or abrasion."

A plastic film overlaminate may be placed on tough duty labels for added protection. Nancy LaRusch, senior sales service for Tapecon Inc. in Buffalo, NY, USA, says, "We very often have to put an overlaminate over all of the labels so weather and chemicals don't attack them."

Gallas says, "Laminates are typically clear and put down as gloss film, matte film or even textured type film. The idea is to protect the inks and keep everything underneath the surface."

Even though many options already exist, research into materials continues. Ray says, "There are special adhesives and substrates being developed all the time to meet the special requirements of the label."

Materials suppliers often research and create new substrates for the marketplace. How do they do it? Rick Neiman, market segment leader for durables at Avery Dennison in Painesville, OH, USA, says, "We talk to end users and converters to respond to existing needs and to anticipate and align with future market trends. We also align ourselves with members of the durable goods supply chain and industry experts to better understand changes and key drivers."

Carolyn Burns, global marketing manager at DuPont Graphics in Wilmington, DE, USA, says, "Sometimes we can anticipate emerging needs in the marketplace and develop products to meet those needs. Other times we answer requests from our customers."

Standards and testing

Since many tough duty labels contain warnings and other essential operation and safety product information, standards organizations are in place to oversee them. Bowers says, "Underwriters Laboratories (UL) and the CSA [Canadian Standards Association] International are the two testing and certification organizations we see involved most frequently. Both of these organizations test and certify electrical, mechanical, industrial, and automotive products and components for safety. They test all sorts of equipment. They also test and certify the label constructions  that are applied to these products."

UL and CSA International offer certifications to companies. GSI Technologies holds about 100 certifications. Bowers says, "Each of them is for very specific constructions. These constructions can be for several applications, and sometimes they're only good for one. The reason we've gotten so many is because we see such a broad spectrum of applications. To get a construction certified can cost between a few hundred and a few thousand dollars. You don't want to have to do that time after time. Most of the time when a customer or prospect comes to us, we have a construction for that application.

"When we don't, we find out specifically what the label will be used for and under what conditions, and sit down with our own technical experts and material vendors and devise what we think is a construction that will meet those requirements. Then we submit it to UL for testing. The way they test the constructions is to subject them to all of the conditions to which they will be exposed in use. UL and CSA employ highly specialized equipment and rigorous techniques to duplicate extreme conditions," says Bowers.

These labels, applied to indoor and outdoor electrical extension cords, must meet the requirements set by Underwriters Laboratories Standard for Safety for Cord Sets and Power-Supply Cords, UL 817. Photo courtesy of WS Packaging.
In addition to the standards organizations, individual companies have their own methods of testing tough duty labels. WS Packaging's Ray says, "Each customer will have their own set of standards and test procedures to be completed prior to shipping labels. Tests could include salt water soak tests, Sutherland Rub tests, chemical resistance tests, Fadeometer tests, Weatherometer tests, and burst strength tests."

Logan from Consolidated Label says, "We leave the testing to our customer. It's their responsibility to approve the material used for their application. We can suggest a product that we believe will work or has worked in the past for similar situations, but what has once worked in the past for one customer won't necessarily work for a current application."

LaRusch says Tapecon has a similar policy. "We don't do testing here. Our customers normally have a very good idea of what's going to happen to these labels and they tell us. We pick the best combination of inks and substrates to make the label."

Andrews Decal Company defers to material suppliers for testing. Gallas says, "We're a relatively small company so we don't really do any internal testing other than inspecting material when it arrives. We typically rely on manufacturers that we purchase material from. They have laboratories to test materials fully. They can do testing on the final product. They have a broader range of specific tests, and they can make recommendations."

Suppliers have various ways of testing their substrates. DuPont's Burns says, "We use ANSI [American National Standards Institute] and TAPPI [Technical Association of the Pulp and Paper Industry] test methods for properties testing. We also send samples out for testing. For example, we have some styles that we accelerate age to see how long they will last exposed to UV outside. Some of our styles have UL, CSA and FDA approval."

According to Neiman, of Avery Dennison, "The majority of our products are first tested internally, then at the converter and end user levels. Our internal testing includes testing of exposure conditions including temperature, water immersion and chemicals. We also conduct performance tests that include visual inspection, print testing and adhesion. UL and CSA recognitions are held for the majority of our durable products. Testing to automotive and other end user requirements is also a common part of our protocol."

The costs

Tough duty labels cost more than traditional labels, for a few reasons. Ray says, "Tough duty labels will cost more than standard labels because the components cost more to manufacture. The costs for testing also need to be added to the cost of the labels. Another factor could be the cost of liability."

Logan explains, "The cost of a label using any of the films will probably be in the range of twice as much as a paper product. This could vary greatly depending on whether a less expensive product such as polypropylene is used or if a more expensive material such as polyester is used for the application. Vinyl is probably priced somewhere in between the polypropylene and the polyester."

Gallas estimates that tough duty labels cost 30 to 50 percent more than traditional labels. He adds that the price could be more if customers want extended life for the labels. Custom adhesives and laminates can also drive up the cost.

This label is meant to withstand chemicals in a laboratory. Photo courtesy of Industrial Labeling Systems.
Kotak finds it difficult to pinpoint an exact cost difference. He says, "It varies from application to application as a large range exists even within the family of products that can be considered tough duty labels. For example, a metalized polyester with extra-aggressive 2-mil adhesive that is 4" x 4" might equal the price per roll of a polyimide label used for electronic circuit board identification but the size of the polyimide label might be 0.375" x 0.25". However, pretty much all materials that can be considered tough duty would cost significantly more (10 times more at times) than the typical paper or styrene type materials."

Avery Dennison's Neiman says, "We have products that sell for 25 percent to 20 times more than a general purpose label."

Although tough duty labels are more expensive, converters' customers need to keep in mind the applications. Bowers explains, "While a prime label might be applied to a $1.39 can of hair spray, a tough duty label might be applied to a piece of equipment that costs several thousand dollars. The prime label is normally constructed of relatively low cost materials, while the tough duty label is a costly construction."

He also points out that volumes for tough duty labels are small compared to those of traditional labels. "It's not untypical to see someone who uses prime labels use tens of thousands of them a week because a consumer product is more often than not a disposable. Volumes for most tough duty labels are relatively small, sometimes as low as 100 pieces," says Bowers.


Certain changes have taken place in the manufacturing of tough duty labels over the years. Gallas says, "In the past, we used to exclusively screen print the tough duty labels because those types of inks have traditionally held up better unprotected and also held up better in the UV area. Presently, we're continuing to print more in the rotary processing (and that could be flexographic) and we can screen print rotary as well. This becomes more efficient because we can print multiple colors, overlaminates with special overlaminate films, and we can diecut in a continuous process or inline, which reduces cost dramatically."

According to Bowers, "We are seeing more sophisticated ways of converting these labels and more sophisticated materials are brought to us by our vendors. Demands placed on labels keep getting tougher, and we and our material partners strive to continue developing solutions to meet those demands."

Converters are always looking for better ways to make tough duty labels. Ray says, "As new materials come on the market we will look to improve efficiencies and reduce costs by testing them to see if they will work in specific applications."

Avery Dennison offers some new tough duty products. Neiman says, "We've recently launched our high performance S8015 adhesive on our Exact trimless program. In addition we have recently launched a full range of validation decal products and a range of polyimide products for lead-free processing. In the next few months we will be introducing a new range of void and checkerboard security products for durable applications."

DuPont offers its Tyvek and Tyvek Brillion to the marketplace for tags and labels, including tough duty labels. Burns says, "The inherent high performance attributes of DuPont Tyvek make it ideal for tough duty labels. Tyvek is not only tough and durable, it is lightweight and highly resistant to moisture, chemicals, punctures, and tears. Tyvek Brillion offers a brighter, whiter, smoother surface to assure excellent printability of bar codes and variable information."

A different purpose

Expectations for tough duty labels differ from their more traditional consumer label counterparts. Bowers explains, "Consumer label users want the label to be conspicuous — it's a marketing tool. Our customers want their labels to go on easily, stay where they belong, and convey critical information for a long time, and our customers want to conduct business with us with as little hassle as possible. If we're doing our job, our labels go into and through our customers' systems without anyone noticing them. When they're noticed, there's a problem. We enjoy anonymity."