Correlation between application temperature and thermal degradation in hot melt adhesives

When it comes to packaging performance and production efficiency, few factors are as overlooked, yet as critical as adhesive temperature. Every factory engineer knows that hot melt adhesives need to run hot to flow and bond effectively. But that same heat is also the catalyst for the adhesive’s downfall.

At higher temperatures, thermal degradation and charring can occur inside the tank, hoses, and applicators. The result? Blocked nozzles, inconsistent bead patterns, unplanned stoppages, and ultimately, costly downtime.

In our latest whitepaper, we investigate what impact different tank and application temperatures have on the rate of degradation in a typical packaging hot melt adhesive — and more importantly, what can be done to slow it down.

Why temperature matters

Hot melt adhesives are designed to be molten during use, flowing from the tank through heated hoses to the application head, whether that’s a slot coater, roller or nozzle. The precise temperature depends on the formulation: some modern cool-running grades can operate efficiently at just 98°C, while older formulations may require temperatures above 200°C.

The problem? Every degree matters. As temperature increases, the chemical stability of the adhesive decreases — oxidation, polymer breakdown, and carbonisation start to take hold. Over time, this manifests as colour darkening, viscosity changes, and ultimately blockages that affect flow and bond consistency.

The aim of the study

Our research set out to answer a simple but important question:
How does application temperature influence the speed and extent of thermal degradation in a hot melt adhesive?

By running controlled tests across a range of tank temperatures, we were able to measure how quickly the adhesive began to degrade, how colour and viscosity changed over time, and what this means for line performance and adhesive life.

What we discovered

The data revealed a clear correlation:

• Higher temperatures = faster degradation.

• Even small increases in tank temperature accelerate charring.

• Extended periods at high heat dramatically affect viscosity and flow.

These findings underline the importance of optimising tank temperature settings, selecting thermally stable adhesives, and using standby modes to reduce heat exposure when lines are idle, all simple steps that can dramatically reduce blocked nozzles and downtime.

Want the full picture?

Our full whitepaper, “Correlation Between Application Temperature and Thermal Degradation in Hot Melt Adhesives,” presents detailed test data, graphs and recommendations for production engineers seeking to maximise uptime and adhesive performance.

👉 Download your free copy by filling in the form below.