Hot Melt Adhesive Application and Service Specialists

What Is Adhesive Degradation And Why Is It Such A Big Problem?



Degraded adhesives are a routine headache in hot melt adhesive applications, and letting the situation get out of hand can result in a range of negative impacts. These include damage to machinery, operational inefficiencies, and unplanned downtime. As a problem that is endemic to hot melt material, understanding adhesive degradation, its effects, and what to do about it can make all the difference to the bottom line. 

Adhesive Degradation Explained

The glue used in hot melt systems (HMSs) is effective due to its thermoplastic properties. HMSs are made of polymers such as ethylene-vinyl acetate and tackifying resins such as hydrogenated hydrocarbons or terpene phenolics, and these allow the mixture to be heated and cooled without altering its chemical structure. However, if the integrity of the polymers is broken, the chemical make-up changes entirely. Instead of moving seamlessly from a solid to a liquid and back again, thermoplasticity is lost, and stubborn lumps of char are formed. 

Why Is Char Such A Problem In Industrial Adhesives?

Any liquid with solid lumps inside it will lose viscosity, interrupting the flow of the material through pipes and nozzles. A loss of viscosity reduces efficiency, increases waste, and has a negative effect on productivity. Over time, char clogs hot melt hoses and nozzles, eventually entering pumps where it results in a permanent failure of fluid seals. As HMSs require high temperatures that take both time and money to achieve, machinery is often kept running even when the line isn’t in use, increasing the production of degraded adhesives. As such, charring is found in most hot melt systems unless they are properly designed and maintained.   

What Can I Do To Reduce The Impact Of Degraded Adhesives?

The accumulation of char happens exponentially, meaning that once a lump of degraded adhesive forms it accelerates the process. As such, regular cleaning is the most effective strategy for managing the problem. Equally, proactive maintenance to ensure that the main char areas such as pipes and nozzles are replaced or rebuilt before the damaging material has a chance to reach critical components such as pumps can save unnecessary costs and downtime. Ideally, any HMS installation should incorporate professional char clearance as part of its fundamental maintenance routine. 

How Can Adhesive Laundry Help?

Managing degraded adhesives is a necessary element of maintaining the chemical balance of hot melts, and is therefore central to operational efficiency and productivity. Our experienced teams can ensure that your equipment is properly maintained, and that char is minimised. For more information, please get in touch for a free quote.