What Is the Best Temperature to Run Hot Melt Adhesive?

Our Technical Applications guys get this question a lot out in the field — so we thought it might be helpful to throw a bit of light onto the subject and give a steer to the engineering and production personnel.

In this article, we’re focusing on hot melts applied via jet nozzles for packaging applications, through systems such as Nordson or Valco, but it’s worth remembering that there are many types of hot melt applications — each with their own ideal operating temperature.

There’s No Single “Right” Temperature

The first thing to say is that there isn’t a hard and fast answer. It’s one of those classic “How long is a piece of string?” questions.

A better question might be:

“What viscosity should I run my adhesive at?”

Of course, hot melt tanks don’t have a viscosity setting — so temperature becomes the key control variable.

Hot melt adhesives are Newtonian fluids, meaning their viscosity changes predictably with temperature:

• As temperature increases, viscosity decreases

• As temperature decreases, viscosity increases

This relationship is critical because the viscosity directly affects how well the adhesive flows, wets the substrate, and forms a strong bond. That’s why correct temperature management is essential to maintaining consistent glue patterns, strong bonds, and trouble-free production.

What the Whitepaper Covers

Our new Whitepaper: Understanding Temperature and Viscosity in Hot Melt Adhesives takes a deeper dive into this topic. It’s designed for production engineers, maintenance teams, and technical buyers who want a clear, data-led understanding of what’s really going on inside the tank.

Inside the whitepaper, we cover:

• What viscosity actually is — and how it governs adhesive behaviour

• Key factors that influence viscosity beyond temperature, such as formulation, application method, and machine setup

• Where to find viscosity and temperature data in technical datasheets and how to interpret it

• How temperature fluctuations affect bond strength, appearance, and adhesive ageing

• Practical recommendations for establishing the ideal operating window for your specific hot melt

Whether you’re troubleshooting nozzle blockages, chasing cleaner glue lines, or simply looking to improve uptime — understanding how temperature affects viscosity will help you optimise both performance and efficiency.

Get the Full Whitepaper

If you’d like to dig deeper into the science — and learn how to fine-tune your line for consistent results — download our whitepaper today.

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Understanding Temperature and Viscosity in Hot Melt Adhesives