Injection Molding: In-Mold PUR Coating Now Comes in Colors

Engel Austria (U.S. office in York, Pa.) and PUR machinery supplier Hennecke (U.S. office in Lawrence, Pa.) have upgraded the capabilities of Engel’s Clearmelt system for integrating injection molding and in-mold coating with a clear, scratch-resistant PUR or polyurea coating. Thanks to Hennecke’s new Colourline Multi-Connect system, Clearmelt can now coat thermoplastic substrates with colored coatings. The modular, plug-and-play Multi-Connect system reportedly allows fast and clean changes of colors. Color changes do not require cleaning and can be accomplished in less than 15 min, according to Hennecke.

Colourline is installed as a stationary isocyanate unit on the injection machine. The Multi-Connect color module with its own heater is a separate unit on a compact, mobile carriage. The Multi-Connect parking station holds up to seven color modules, including a clear,
uncolored coating, if desired. Additional parking stations can be added, if necessary. The user can undock the desired color module from the parking station, move it to the isocyanate unit, and re-dock it there. The isocyanate unit then takes over control of the color module. Each color module has its own mixhead on which the isocyanate unit is attached. This ensures that each color circulates in its own system and prevents color mingling when changing colors. Because color pigments are highly abrasive, Hennecke developed the HT30evo piston pump for this purpose. Each color module has its own pump.