Temperature plays a vital role in hot melt adhesive applications, influencing adhesive performance and overall stability. In this blog post, we explore the effects of temperature on hot melt adhesive and present the findings of a recent test that highlights the significance of thermal stability.
Discover why using a hot melt adhesive that maintains its integrity at lower temperatures can lead to improved operational efficiency and reduced downtime. Watch the video below for a brief overview:
The Test: Comparing How the Same Glue Performs When Running at Different Temperatures
To understand the impact of temperature on hot melt adhesive, we conducted a comprehensive test using the same adhesive across three different temperatures: 120, 160, and 180 degrees Celsius. Our focus was to evaluate how quickly they degraded under varying temperatures.
The Results: Degradation and Charring Effects
First of all, it's important to understand how degradation can be measured. In this whitepaper we measure how quickly the glue changes (normally increases) in viscosity with time (or to you and me, that's how fast the glue thickens up and goes dark - causing blocked nozzles and other issues).
The thermal stability chart produced from this test revealed fascinating insights. At 120 degrees Celsius, the degradation of the adhesive was minimal, with only 0.4% increase in viscosity observed. However, as the tank temperature increased to 160 and 180 degrees Celsius, the degradation became significantly more pronounced. The 160-degree test exhibited 8.5% viscosity increase, while the 180-degree test displayed 9.8% viscosity increase. These findings demonstrate the critical importance of temperature control when it comes to hot melt adhesive performance.
The Consequences: Charring, Blocked Nozzles, and Downtime
The degradation and charring of hot melt adhesive can have adverse effects on equipment and overall production efficiency. As the adhesive degrades, it can lead to charring in the tank and result in blocked nozzles. This, in turn, causes unexpected downtime and disrupts the production process. Additionally, blocked nozzles necessitate frequent cleaning and replacement, leading to increased maintenance costs and reduced productivity.
The Benefits of Running Your Adhesive Cooler
Less Unplanned Maintenance: By using a hot melt adhesive that maintains its stability at lower temperatures, you can significantly reduce unplanned maintenance requirements.
Reduced Downtime: With less charring and fewer blocked nozzles, the risk of downtime due to adhesive-related issues is substantially decreased, ensuring a smoother production process.
Fewer Blocked Nozzles: A low-temperature hot melt adhesive minimises the occurrence of blocked nozzles, allowing for uninterrupted adhesive application and improved operational efficiency.
Fewer Replacement Filters Needed: Reduced degradation and charring result in cleaner adhesive flow, reducing the need for frequent replacement of filters and saving on maintenance costs.
Keep your glue tank operating at a lower temperature than your hose and gun.
This will mean your glue is kept cooler for longer.
Temperature control is a critical factor in hot melt adhesive applications. Our test results clearly demonstrate that the thermal stability of the adhesive directly affects degradation, charring, and potential issues such as blocked nozzles. By selecting a high-quality hot melt adhesive that exhibits minimal degradation and can operate at lower temperatures, you can experience reduced maintenance, improved productivity, and fewer downtime incidents.
Using the Stand-by Button on a Nordson Hot Melt Adhesive Tank
A little known secret in the world of hot melt gluing is the stand-by button on Nordson tanks as pictured below. This (in its default setting) will drop the set temperatures down to 75% of whatever they were set at - e.g. if your glue is set at 160°C, after pressing the button, the temperatures will drop to 120°C.
Why is this a good thing? Well if you've read our recent whitepaper titled "What is the best temperature to run hot melt adhesive" you'll know that the hotter the glue is, the more charring and blockages you'll get (fill out the form at the bottom to receive the whitepaper if you've not read it).
But did you know that generation 6 technology actually runs at a lower temperature than a Nordson stand-by button does when your standard operating temperature is 160°C! Gen 6 runs at just 98°C in the tank - all the time - so you never need to go into stand-by. Imagine never having to wait for your glue to heat back up to temperature when coming out of stand-by!
Interested in learning more about the technical details of the test? Fill out the form below to receive our Technical Whitepaper where we go into detail of how the test was conducted and discuss viscosity and the effect that it has.