It’s that time again. Winter. And with it I get reports of an all too familiar problem in the field: “My labels won’t stick!” These are the same labels you’ve always used and haven’t had problems with before. Is the adhesive different? Is it a bad batch? What changed? The problem isn’t that the adhesive is different or defective. You need a material with a low temperature adhesive that is designed to be applied in cold temperatures.
1) Application temperature is different than service temperature
When we are talking low application temp adhesives, we mean the ambient and substrate temperatures at which adequate initial adhesion can be achieved when a label is applied or ‘installed’. This is not to be confused with service temperature; the temperatures the label will endure over its useful service life without affecting adhesion. When you require a material that will be applied in cold weather, make sure it has a low application temperature adhesive.
2) How label adhesives work
To understand what makes low temperature adhesives different, you need to understand how label adhesives work. Peel-and-stick labels use what we call pressure sensitive adhesives, or PSA’s. Adhesion is accomplished by nothing more than rubbing in place with firm pressure. But ‘standard’ PSA formulations are designed for adhesion in varying specified temperature ranges generally above 50-65 degrees F. This is because PSA’s are viscoelastic; meaning they exhibit the ability to change and return to shape when force is applied to them, but also exhibit a viscosity factor that allows them to flow to a certain degree over time. And it is this viscoelastic property that allows the thin adhesive layer on the back of the label to make ‘intimate’ contact with and take the form of the micro surface irregularities of the substrate to which they are adhered; thus maximizing contact area and therefore, adhesion.
3) The difference between low temperature and standard temperature PSA’s
PSA’s are thick enough so as to be able to hold a shape but still remain sticky at typically comfortable ambient temperatures. ‘Gummy‘ might be a term that describes their form. But at temperatures lower than a standard PSA is engineered for it becomes very stiff and resists this ability to flow and take the shape of the surface texture to which it is applied. We are familiar with and see this property exhibited of thick fluids like honey or heavy petroleum oils; which behave as thinner fluids and flow easily in warm temperatures, but as thicker fluids and flow very poorly in cold temperatures. “Slower than molasses in January” comes to mind. What makes low temperature adhesives special is that they are engineered to flow readily at nearly freezing or even freezing temperatures down to a specified minimum… some as low as zero degrees F or below.
4) Limited material options
Getting your specified or preferred ‘standard’ application temp label material with a low temp adhesive isn’t as simple as just asking your decal manufacturer to change the adhesive. That’s because the manufacturer who prints your labels doesn’t coat the adhesive to the material. This is the role of specialty label and plastic film ‘converters’, from whom decal manufacturers source the materials which they use to manufacture their products. These materials often come in large log roll or sheet form and are often pre-configured product offerings, and custom configurations using specialty low temp adhesives would require large quantity and long term purchase commitments. And the market for label materials to be used in applications where they are expected to be applied in cold temperatures is not large. This is especially true of retroreflective traffic sheeting materials, which are almost entirely engineered for use in the traffic sign industry where these materials are applied by sign manufacturers in controlled temperature ‘shop’ conditions.
5) Low application temperature decal materials can be more costly
The more limited specialty market demand usage of label materials with low temperature adhesives simply makes their manufacturing and stocking/supply less efficient for the material converters that configure them, and therefore their sourcing and stocking/supply by label manufacturers more costly. This leaves the specifiers and buyers of labels with 3 basic alternatives: 1) Simplify specification, buying, and inventory by utilizing a low temp material in all applications, regardless of temperature relative to season of application. This however can result in limited options, other possible performance compromises, and higher expenditure where decals don’t require the low temp adhesive. 2) Specify and stock different materials for normal and low temp use. This however can add complexity to inventory and directed use. 3) Specify and use ‘standard’ temp materials and refrain from applying in cold weather. This minimizes cost and widens available material choices.
Electromark low application temperature materials
Electromark currently has one standard offering non-reflective vinyl label material with a freezer grade adhesive that can be applied in temperatures down to -20 degrees F, and one standard offering retroreflective high intensity material that can be applied in temperatures down to 14 degrees F. We do source materials outside of our standard offering, and can research and offer custom alternatives.