IWG provides compatible flushing agents and cleaners designed to safely remove adhesive residues and interrupt the chemical reaction of PUR hot melt adhesives, helping to protect system components and maintain application quality.
Use of Flushing Agents
Flushing agents are used to displace adhesive residues from hoses, rollers, and internal application components while preventing unwanted chemical reactions. Before starting the cleaning process, compatibility between the adhesive and the flushing agent must be confirmed.
In closed application systems, both the PUR hot melt adhesive and the flushing agent must be evenly melted. Uneven melting can cause blockages in hoses or nozzles due to premature reactions.
Because liquid flow velocity is lower near hose walls than at the center, an adequate quantity of flushing agent is essential to ensure thorough cleaning throughout the system.
Influence of Viscosity
In addition to flow behavior, viscosity plays a key role in effective purging. If the flushing agent viscosity is too low, adhesive residues along the hose walls may remain. Technical Data Sheets should be consulted to verify that the viscosity of both adhesive and flushing agent is suitable for complete removal.
Drum Change and Contamination Prevention
During drum changes, contamination must be avoided at all times. The heating plate should be cleaned thoroughly, and any adhesive residues around the sealing rings must be removed. Lightly greasing the sealing rings with a water-free, acid-free lubricant helps simplify cleaning and significantly reduces downtime during drum replacement.
To minimize moisture exposure, adhesive drums should not remain open longer than necessary.
Roller Application System Cleaning Procedure
Drain the roller application system using the machine’s cleaning mode (reverse direction). Collect adhesive residues in a coated drip tray or suitable container.
Remove remaining adhesive from the application roller using a wooden spatula. Roller rotation should be switched off during this step.
Return the system to standard operation mode, fill with a suitable liquid cleaner, and heat until fully melted.
Allow the cleaner to soak for 10–15 minutes while the rollers rotate in standard operation mode.
If required, repeat the cleaning process using an additional cleaner to address heavier contamination.
Run the rollers in reverse mode to drain the cleaner, then repeat the procedure up to three times depending on the level of soiling.
After cooling—but while the system is still warm—remove remaining cleaner residues using protective gloves and a dry, lint-free cloth. Slightly moisten the cloth with a suitable solvent cleaner if necessary. Heavily crosslinked PUR adhesive residues can only be removed mechanically.
Cleaning of Metal Components
Metal parts exposed to adhesive residues should be cleaned using appropriate chemical cleaners approved for PUR systems. Mechanical removal may be required for fully cured adhesive deposits.
