From sealing a box of pasta to securing a label on an energy drink, hot melt adhesive is one of the most versatile products in packaging operations. It enables manufacturers to package the products consumers use daily efficiently and safely. Hot melt packaging adhesives are designed to set quickly under short compression times to form a strong bond. To meet consumer demand, packaging lines need to run smoothly and avoid downtime. One of the culprits reducing the efficiency of a packaging operation is char – it can impact the hot melt equipment and increase downtime. Once char is in the system, removing it can be difficult.
Char results from heat, contaminants and oxidation of hot melt adhesive. As the polymer chains begin to breakdown, the over-exposed adhesive begins to burn – or blacken – and clog the filters, hoses or nozzles on the hot melt equipment. Char can wreak havoc on the dispensing and sealing of consumer goods packaging. The cause of char is difficult to diagnose, and the sources can be a combination of equipment settings, operating processes and adhesives. The conditions which make the hot melt system more susceptible to the formation of char are:
• Operating equipment above recommended temperatures for hot-melt adhesive
• Overexposing hot melt adhesive to high heat for long periods of time
• Extending exposure of hot melt adhesives to oxygen and contaminants
These conditions can be easily remedied by implementing some best practices on the hot melt packaging line.